CA1315862C - Microwave landing system with fail-soft switching of dual transmitters, beam steering and sector analysis - Google Patents
Microwave landing system with fail-soft switching of dual transmitters, beam steering and sector analysisInfo
- Publication number
- CA1315862C CA1315862C CA000565878A CA565878A CA1315862C CA 1315862 C CA1315862 C CA 1315862C CA 000565878 A CA000565878 A CA 000565878A CA 565878 A CA565878 A CA 565878A CA 1315862 C CA1315862 C CA 1315862C
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- wave energy
- array
- coupled
- energy signals
- switch
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/74—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission for increasing reliability, e.g. using redundant or spare channels or apparatus
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S1/00—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith
- G01S1/02—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith using radio waves
- G01S1/022—Means for monitoring or calibrating
- G01S1/024—Means for monitoring or calibrating of beacon transmitters
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S1/00—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith
- G01S1/02—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith using radio waves
- G01S1/08—Systems for determining direction or position line
- G01S1/44—Rotating or oscillating beam beacons defining directions in the plane of rotation or oscillation
- G01S1/54—Narrow-beam systems producing at a receiver a pulse-type envelope signal of the carrier wave of the beam, the timing of which is dependent upon the angle between the direction of the receiver from the beacon and a reference direction from the beacon; Overlapping broad beam systems defining a narrow zone and producing at a receiver a pulse-type envelope signal of the carrier wave of the beam, the timing of which is dependent upon the angle between the direction of the receiver from the beacon and a reference direction from the beacon
- G01S1/56—Timing the pulse-type envelope signals derived by reception of the beam
Abstract
MICROWAVE LANDING SYSTEM WITH
FAIL-SOFT SWITCHING OF DUAL TRANSMITTERS, BEAM STEERING AND SECTOR ANTENNAS
ABSTRACT OF THE DISCLOSURE
An MLS system having redundant subsystems.
Dual signal sources feed dual power dividers. A first switch array selects the power divider to be used and provides the selected signals to an array of phase shifters. A second switch array provides the phase shifted signal, which may be amplified, to either a primary array having elements for radiating a scanning beam or a recombining network having outputs connected to auxiliary antennas. A third switch array provides control signals to the array of phase shifters from either a main beam steering unit or a standby beam steering unit. Alternatively, the dual signal sources feed a single power divider through a circulator.
Duplicate auxiliary antennas may be used with antenna switches located before the power dividers or circulator for selectively providing the signals to the auxiliary antennas instead of the primary array.
FAIL-SOFT SWITCHING OF DUAL TRANSMITTERS, BEAM STEERING AND SECTOR ANTENNAS
ABSTRACT OF THE DISCLOSURE
An MLS system having redundant subsystems.
Dual signal sources feed dual power dividers. A first switch array selects the power divider to be used and provides the selected signals to an array of phase shifters. A second switch array provides the phase shifted signal, which may be amplified, to either a primary array having elements for radiating a scanning beam or a recombining network having outputs connected to auxiliary antennas. A third switch array provides control signals to the array of phase shifters from either a main beam steering unit or a standby beam steering unit. Alternatively, the dual signal sources feed a single power divider through a circulator.
Duplicate auxiliary antennas may be used with antenna switches located before the power dividers or circulator for selectively providing the signals to the auxiliary antennas instead of the primary array.
Description
1 BACKGROUND OF THE-lNvrN-rIoN ' ~ ) 62
2 1 Field of the Invention .
3 The invention generally relates to
4 scanning antennas and, in particular, to microwave landing systems using a signal format which requires 6 multiple antenna functions to provide the signals over 7 wlde coverage sectors.
8 2. Description of the Prior Art 9 Antenna techniques are known which lû use the phased array scanning beam antenna of a 11 microwave landing system (MLS) to broaden its 12 radiation pattern to satisfy the data antenna 13 requirements. Such techniques generally employ phase 14 spoiling of the phased array aperture. The fundamental limitation of this technique is that it 16 cannot provide the out-of-coverage indications (OCI) 17 signals and the 360 data signals without employing 18 a single thread multiple port rf switch. This 19 technique is deficient because it is subject to slngle point failures within the phased array which can cause 21 substantial radiation pattern minima when used in the 22 data antenna mode (low gain - broad pattern). These 23 minima are very difficult, if not practically 24 impossible, to monitor and detect. In addition, single point system failures also exist and can create 1 3 ~ 2 1 significant sa-~ety risks in certain operational 2 scenarios.
3 The MLS signal format requires multiple 4 antenna functions to provide the signals over wide coverage sect.ors. The format also provides -for signal 6 transmission outside the normal coveraqe volume, e.g., 7 out-of-coverage indication signals (ûCI). Inherent 8 growth capabilities in the system such as 360 data 9 link coverage, also require additional antennas in many practical applications. Because of the multiple 11 antennas required for MLS, an antenna switch is used 12 to connect a transmitter sequentially in time to each 13 antenna port. Although redundant transmitters and 14 control electronics can be enacted on line to provide signal continuity in the event of a failure, the 16 switching components (rf and logic) are a limiting 17 factor in supporting the requirements for signal 18 continuity in high reliability applications.
It is an object of this invention to 21 provide an MLS employing redundant rf switching of 22 dual signal sources to minimize the effect of switch 23 failures.
24 It is another object of this invention to provide an MLS system with dual signal sources ~31~62 1 connected to a primary element array via a passive 2 circulator and switch cornbination which perrnits 3 continued operation even during failure (i.e.
4 fail-operational).
It is ano-ther object of this invention to 6 provide an MLS system with rf and beann steering logic 7 switch arrays for eliminating single point failures.
8 It is another object of this invention to 9 provide a microwave landing system with a recombining network and switch array for driving auxiliary wide 11 sector antennas with fail-soft performance.
12 The antenna system according to the 13 invention radiates wave energy signals into a selected 14 region of space and in a desired radiation pattern.
The system includes means for supplying wave energy 16 signals and a primary aperture comprising an array of 17 primary antenna elements. An auxiliary aperture 18 comprising an array of auxiliary antennas is also 19 provided. Recombining means may be used for recombining supplied wave energy signals and for 21 supplying the recombined signals to the auxiliary 22 aperture. First means phase shifts the supplied wave 23 energy signals. Second means selectively couples 24 phased signals provided by the first means to either the primary antenna elements or to the recombining 26 means. The first means provides a beam radiated by ~ 3 ~
1 the primary array in accordance with a predeterrnined 2 pattern when said second means couples phased signals 3 to the primary array. The second means also provides 4 a beam which is radiated by at least one of the auxiliary antennas when the first means couples 6 supplied wave energy signals to the recombining means.
7 The means for supplying may be comprised 8 of means for supplylng first wave energy signals and 9 means for supplying second wave energy signals. The means for supplying second wave energy signals is 11 independent of the means for supplying first wave 12 energy signals. Third means selectively couples one 13 of either the first wave energy signals or the second 14 wave energy signals to the first means. The first means may be comprised of an array of phase shifters, 16 a first beam steering unit for controlling the phase 17 shifters and a second beam steering unit, independent 18 of the first beam steering unit, for controlling the 19 phase shifters. Fourth means selectively couples one 2û of either the first beam steering unit or the second 21 beam steering unit to the array of phase shifters.
22 For a better understanding of the present 23 invention, together with other and further objects, 24 reference is made to the following description, taken in conjunction with the accompanying drawings, and its 26 scope will be pointed out in the appended claims.
~31~2 2 Figure 1 is a block diagram of a microwave 3 landing sys-tem (MLS) according tû the invention 4 including dual signal sources and a recombining network for driving auxiliary antennas.
6 Figure 2 is a detailed block diagram of 7 one preferred embodiment of the MLS illùstrated in 8 Figure 1.
9 Figure 3 is a schematic illustration of a Butler matrix for use as a recombining network 11 according to the invention.
12 Figure 4 is a functional block diagram of 13 a microwave landing system (MLS) according to the 14 invention including dual signal sources and antenna switches for supplying dual auxiliary antennas.
16 Figure 5 is a functional block diagram of 17 an MLS according to the invention including dual 18 signal sources fed through a circulator and antenna 19 switches for supplying dual auxiliary antennas.
Figure 6 is a functional block diagram of 21 an MLS according to the invention including dual 22 signal sources fed through a circulator and a 23 recombining network for driving auxiliary antennas.
, 1 DETAILED DESCRIPTION OF Tl-lE INVENTION ~ g ~2 .
2 The standards specified by the Federal 3 Aviation Administration and the International Civil 4 Aviation Organization (ICAO) define the operational reliability requirements for the various levels of 6 MLS. The mûst reliable level defined by the standards 7 is known as category IIIo In category III systems it 8 is necessary to have redundant operation of various 9 subsystems in order to meet the operational lû requirements and avoid a break in the signal 11 continuity because of critical failures. The MLS
12 signal format requires multiple antenna functions to 13 provide the signals over the nominal coverage limits.
14 The format also provides for signal transmission outside the normal coverage volume, for example, ûCI -16 out-of-clearance indication. Inherent growth 17 capabilities in the system, such as 36û data 18 transmission, also require additional antennas in 19 practical applications. The multiple antennas 2û required for MLS result in the use of antenna switches 21 for connecting the transmitter sequentially in time to 22 each antenna port. Redundant transmitters and control 23 electronics can be employed on line to provide signal 24 continuity in the event of a failure. However, a switching component (rf and logic) is a fundamental 26 aspect which cannot be practically duplicated. This 1 presen-ts a limiting factor in supportinq the 13 ~ 2 2 requirements for signal continuity in Category III
3 applications.
4 In accordance with the invention, this dependency on the need to use a switching component to 6 connect auxiliary antennas may be minimized by using a 7 recombining network. rhe network recombines the power 8 which would have been radiated by each element in the 9 phased array of the primary aperture. The power is lû recombined into a multiplicity of beam ports which are 11 connected to auxiliary antennas such as data antennas, 12 OCI antennas, clearance antennas and C-Band 13 synchronization antennas. The technique employs a 14 single-pole, double-throw (SPDT) switching component at the output of each phase shifter in the array in 16 order to create a switch mechanism which is inherently 17 redundant and which fails soft.
18 Furthermore, it is necessary to have 19 independent, redundant transmitters and beam steering units (BSUs) in order to meet operational 21 requirements. In the past, such transmitters and BSUs 22 were each connected through a single switch so that 23 when one ~ailed, the other would be selected. An 24 inherent flaw in this connection approach is that even though the transmitters and BSUs are redundant, the 26 switch is not and a switch failure results in a 1 critical system failure. The invention distributes 2 the switching of the redundant transmitters and of the 3 BSUs so that such switching is not dependent on any 4 one switch. Alternatively, a circulator and switch may be used to link the redundant transmitter to the 6 phased array in a fail-operational confiquration.
7 Referring to Figure 1, the redundant 8 transmitters are illustrated by the first signal 9 source lû and second signal source 2û which is lû independent of the first signal source 10. The first 11 signal source 10 provides its signal via line 30 to 12 first power divider 40 which distributes the signal to 13 various outputs 51, 52, 53, 54 of the first power 14 divider 40. Similarly, second signal source 20 provides its signal via line 6û to second power 16 divider 70 which distributes the provided signal to 17 its various outputs 81, 82, 83, 84. The outputs of 18 power dividers 40 and 70 are provided to a first 19 switch array 90.
Switch array 90 is a group of single-pole, 21 double-throw switches 100. Each SPDT switch 100 has 22 inputs 101 and 102 with a single output 103. The 23 position of each switch is controlled by either the 24 main beam steering unit (BSU) 150 or standby BSU 140.
Generally, each input 101 of each SPDT switch 100 26 would be connected to one of the outputs 51, 52, 53, ~31~ 2 1 54 of ~irst power divide:r 40. The correspondinq input 2 102 of SPDT switch 100 would be connected ko one of 3 the corresponding outputs 81, 82, 83, 84 of second 4 power divider 70. In normal operation, the firs-t signal source would be selected and would provide 6 power to the system via the first power divider 40 and 7 all SPDT switches 100 would be in the UP position so 8 that each input 101 would be connected to switch 9 output 103. Upon detection of a failure in the first signal source 10, BSU 150 would operate the SPDT
11 switches 100 via control 104 and move each switch 100 12 to the DOWN position so that input 102 would be 13 connected to switch output 103. This would result in 14 the second signal source 20 via power divider 70 providing the necessary rf power to the MLS. As a 16 result, failure of one of the SPDT switches 100 does 17 not totally disable the MLS and would only affect the 18 particular port through which the failed switch is 19 connected.
The outputs of first switch arra~/ 90 are 21 connected to phase shifter array 120 for controlling 22 the scanning of the radiated beam in response to 23 controls provided by either BSU 130 or standby BSU 140 24 via third switch array 131. Switch array 131 is a group of single polej double throw switches 132. Each 26 SPDT switch 132 has inputs 133, 134 with a single ~ 3 ~
1 output 135. The position of each switch is controlled 2 by either the main BSU 13û or standby BSU 14û.
3 Generally, each input 133 of each SPDT switch 132 4 would be connected to one of the outputs of main BSU
13û. The corresponding input 134 of SPDT switch 132 6 would be connected to one of the corresponding outputs 7 of standby BSU 14û. In normal operation, the main BSU
8 130 would be selected and would provide control 9 signals to phase shifter array 120. All SPDT switches 132 would be in the LEFT position so that each input 11 133 would be connected to switch output 135. Upon 12 detection of a failure of the main BSU 130, monitor 13 and switchover logic 150 would operate the SPDT
14 switches 132 and move each to the RIGHT position so that input 134 would be connected to switch output 16 135. This would result in the standby BSU 14û
17 providing control signals to phase shifter array 120.
18 As a result, failure of any one of the SPDT switches 19 132 does not create a single point system failure and cannot totally disable the MLS. A switch failure 21 woùld only affect the particular phase shifter with 22 which the failed switch is associated.
23 Generally, control of the system operation 24 would be un~er main BSU 13û in coordination with monitor and switchover logic 150. Logic 150 is 26 constantly analyzing various monitor outputs provided ~ 3 ~
1 by one or more rnonltors (not shown). As shown in 2Figure 1, each BSU 1~0, 140 controls ~he first switch 3 array 9û, the second switch array 170 (described 4 below) and the third switch array 131. The controls are illustrated in this manner because, as shown in 6 Figure 2, this facilitates a modular configuration.
7 There may also be a requirement for redundancy (not 8 illustrated) with regard to monitors 15û.
9The outputs from phase shifter array 12û
lû which include phase shifted signals are then provided 11 via distributed amplifier array 160 to second switch 12 array 17û. Amplifier array 160 is a plurality of 13 in-line amplifiers, one for each output port of the 14 phase shifter array 120. Switch array 17û is a group of single pole, double throw switches 180. Each 16 switch has an input 181 and two outputs 182, 183.
17 Each output 182 is connected to a corresponding 18 element of the primary element array 190 to power the 19 primary antenna elements for providing a scanning MLS
2û beam. Each output 183 is connected to the 21 corresponding input of recombining network 2ûO for 22 powering the auxiliary antenna elements. The position 23 of each SPDT switch 180 of second switch array 170 is 24 controlled by BSU 130 or BSU 140 via third switch array 131. In the DOWN position, each SPDT switch 180 26 powers the primary element array l9û via output 183.
-12~
~ 3 ~ 2 1 In the UP position, each SPDT switch 180 powers the 2 recombining network 200 via output 182.
3 As with the -firs-t switch array 9û, the 4 second switch array permits supplied energy signals to be either supplied to the primary element array l9û or 6 to the auxiliary element array 21û without the 7 supplying of such signals being dependent upon any one 8 single-pole, double-throw switch or being subject to 9 any single point failure.
lû An MLS generally has several modes o-f 11 operation. In one mode, a Tû-FR0 beam is scanned in 12 order to provide aircraft within the scanning beam 13 azimuth or elevation information. In other modes of 14 operation, auxiliary antennas radiate signals which provide supplemental landing information. Primary 16 element array 190 includes a plurality of antenna 17 elements which, when supplied by wave energy signals, 18 provide a beam of radiated energy. The beam is 19 electronically scanned Tû and FR0 by varying the phase 2û of the input signals to the antenna elements. The 21 phase is varied by phase shifters 120.
22 During auxiliary operationJ one or more 23 auxiliary antennas radiate information. Auxiliary 24 element array 210 is a grouping of various auxiliary antennas which are used to provide the supplemental 26 information to aircraft within the range of the MLS.
~ 3 ~
1 In the prior art, auxiLiary antennas are generally 2 powered directly by the siqnal source. As indicated 3 abûve, an antenna switch is used to select the 4 particular antenna or group of antennas which are connected to the signal source. As a result, the 6 reliability of the auxiliary antenna operation is 7 dependent upon the single antenna switch which selects 8 the antenna and connects it to the signal source.
9 In contrast, the invention employs a second switch array 17û which supplies power to a 11 recombining network 2ûû to feed the auxiliary element 12 array 210. During auxiliary operation of the MLS, 13 each SPDT switch 180 is in the DOWN position so that 14 supplied signals are provided to recombining network 2ûû. The number of inputs to recombining network 2ûO
16 equals the number of inputs to primary element array 17 110. The number of outputs for recombining network 200 18 depends upon the number of elements in the auxiliary 19 element array and may be, for example, four or eight.
2û Recombining network 20û is any standard network, such 21 as a Blass or Butler array, which recombines the 22 signals at the input according to a predetermined 23 coupling arrangement and provides the combined signals 24 at the outputs of the network 200.
During auxiliary operation, the beam 26 steering unit 130 controls the phase shifters 120 so $ ~ 2 1 -that the phase o~ the signals input into the 2 recombining network 2ûû result in illuminating the 3 partlcular output of network 200 which is connected to 4 the particular auxiliary antenna of array 210. For example, assume that the OCI auxiliary antenna mus-t be 6 illuminated. Also, assume that the ûCI antenna is 7 connected to the first output port of recombining 8 network 2ûO. Since the characteristics of the 9 recombining network are known and the coupling lû arrangement within the network preset, appropriate 11 illumination of the inputs of network 20û will result 12 in output 1 being primarily illuminated. In this way, 13 the operation of each auxiliary antenna is not 1~ dependent on any single antenna switch.
Figure 2 illustrates one preferred 16 embodiment of the invention of Figure 1. Dual signal 17 sources 300 and 301 separately feed dual power 18 dividers 302, 3û3. In particular, a first transmitter 19 (TXl) feeds the first power divider 302 and a second transmitter (TX2) feeds the second power divider 303.
21 The outputs of each of the power dividers is connected 22 to the input to one of the modules 305-308 which 23 includes a single pole, double throw switch 3û5a-308a, 24 a phase shifter 305b-308b, a second single pole, double throw switch 305c-308c and a third single pole, 26 double throw switch 3û5d-3û8d. Modules 3û5-308 ~15-~ 3~ '2 1 comprise the combination o~ ~irst switch array 90, 2 phase shifters 120, second switch array 170 and third 3 switch array 131 as illustrated in Figure 1. Main ~SU
4 bus 311 provides the control signals between main BSU
309 and each of the SPDT switches. Main BSU bus 311 6 also provides one of the input signals to SPDT
7 305d-3û8d. Standby BSU bus 312 provides switch 8 control signals and the other input signal to SPDT
9 305d-308d. For simplicity, connectors to the switches lû from the BSUs are illustrated as buses. However, each 11 SPDT may be directly connected to a separate port of 12 the BSU.
13 Single pole, double throw switches 14 305a-308a correspond to the first switch array 90 of Figure 1. Switches 305c-308c correspond to the second 16 switch array 170. Switches 3û5d-308d correspond to 17 the third switch array 131. Phase shifters 305b-308b 18 correspond to phase shifter array 120. Amplifiers 19 3û5e-308e correspond to the distributed amplifier array 160. Elements 33û-333 correspond to the primary 21 element array 19û.
22 ûperation of the preferred embodiment 23 illustrated in Figure 2 is as follows. During 24 scanning cycles, main BSU 309 instructs the switches via bus 311. Switches 305a-308a are placedjin the UP
26 position, switches 305c-308c are placed in the ûOWN
~ 3 ~ 2 1 position and switches 305d-308d are olaced ir~ the UP
2 position. This results in transmitter 300 providing 3 signals via the first power divider 302 to -the primary 4 antenna elements 33û-333. In addition, phase shifters 305b-308b receive control signals frorn the main BSU
6 309 via bus 311 which result in the scanning of the 7 beam ra~iated by elements 33û-333. During auxiliary 8 modes, main BSU 309 would place switches 305c 308c in 9 the UP position. This would result in supplied wave energy signals being provided to recombining network 11 350. In addition, main BSU 317 would control phase 12 shifters 305b-308b so that the phased signals being 13 provided to recombining network 350 would illuminate 14 the appropriate auxiliary antenna port. This aspect of the invention is described in more detail below.
16 In contrast, during scanning modes, main BSU is 17 adjusting the phase shifter 3û5b-308b to radiate a 18 scanning beam via the primary array of elements 1~ 330-333.
In the event of a failure, monitor and 21 switchover logic 320 would evaluate the failure and 22 correct the problem. Logic 320 may be advised of a 23 failure via field monitors, inherent monitors within 24 the system, information derived from built in test equipment or from information provided by external 26 sources. For example, if prlmary signal source 3ûO
1 were inoperative, main BSU 309 would instruct SPDT
2 switches 305a-308a -to switch to the DOWN position.
3 This instruction would be provided via main bus 311 so 4 that power divider 303 would be supplying the input signals via secondary source 301. If a failure in the 6 main beam steering unit 317 is detected, standby BSU
7 310 controls switches 305d-308d and places the 8 switches in the DOWN position so that standby BSU 310 9 is providing control signals via bus 312 to phase shifters 305b-308b.
11 Figure 3 illustrates one embodiment of 12 recombining network 350 in the form of a Butler 13 (factorial) array matrix having 100% circuit 14 efficiency. Recombining network 350 has input ports 1, 2, 3 and 4, linked by phase shifters 351 and 16 couplers Cll, C12, C13, C21 and C22 to 17 output ports A and B. This forms a four element, two 18 beam matrix. Providing signals of phase Ell, E12, 19 E13 and E14 to input ports 1-4, respectively, will result in illuminating output port A. On the other 21 hand, providing signals of phase E21, E22, E23 22 and E24 to input ports 1-4, respectively, will 23 result in illurnination of the output port B. For a 24 more detalled description of the operation of such arrays see Microwave Scanning Antennas edited by R. C.
26 Hansen, Chapter 3, Academic Press, 1966.
1 For example, a data antenna rnay be ~ 3~ ~g 6 2 connected to output port A and an OCI antenna to 3 output port B. During ûCI cycles, main BSU places 4 switches 305c-308c in the UP position and provides signals to the input ports l-ll having phases E21, 6 E22, E23 and E24, respectively. During data 7 cycles, main BSU 309 places switches 305c-308c in the 8 UP position and provides signals to the input ports 9 1-4 of recombining network 350 at the phases Ell, E12, E13, E14, respectively. This results in 11 illumination of only port A and transmission of such 12 information by the data antenna. The selection of the 13 data and OCI antennas, therefore, does not depend upon 14 any single rf switch.
Figures 4, 5 and 6 illustrate various 16 alternative embodiments of the invention. The same 17 reference characters have been used for the same 18 structure which appears in Figures 1, 4, 5 and 6.
19 In Figure 4, the recombining network becomes unnecessary if the data antenna is the only 21 auxiliary antenna which is considered critical to the 22 operation of the system. Antenna switch 400 is 23 located between power source 10 and first power 24 divider 40. A second antenna switch 401 is located between power source 20 and second power divider 70.
26 During auxiliary modes of operation, the controlling ~ 3 ~ 2 1 beam steering unit activates the apPrOpriate antenna 2 switch to provide a signal for radiation by the 3 selected data antenna. Durinq normal operation in the 4 scanning mode, antenna switch 4ûO would connect pûwer supply lû to first power divider 40. During normal 6 operation in the auxiliary mode, antenna switch 400 7 would connect power supply 10 to first data antenna 8 411. During the back-up scanning mode, antenna switch 9 401 would connect power supply 20 to second power lû divider 70. During back-up operation of the auxiliary 11 mode, power supply 20 would be connected to second 12 data antenna 411 via antenna switch 401. In Figure 4, 13 main BSU 130 is shown as having control bus 412 14 connected to phase shifter array 120, first switch array 90 and antenna switches 400 and 401 to control 16 the operation of these subsystems. Similarly, standby 17 BSU 140 is connected by standby bus 413 to the same 18 subsystems. Alternatively, the main BSU 130 and 19 standby BSU 140 may be connected to the subsystems via a third switch array as illustrated in Figure 1 or by 21 an array of OR gates or other logic circuits which 22 would function as switches.
23 Figure 5 illustrates another alternative 24 embodiment of the invention in which a passive ferrite circulator 402 is used to interconnect the alternative 26 power sources to power divider 403. Circulator 402 is 1 a standard passive ferrumagrlekic device such as a 2 passive waveguide junction. Each port A, B, C of 3 circulator 402 is -related to the other such that when 4 power is fed to any one port, it is transferred to the next port as indicated by the arrow. The invention as 6 illustrated in Figure 5 would be useful when it is 7 unnecessary to employ switching arrays such as 8 switching array 90, 131 or 170. Although circulator 9 402 and power divider 403 can be considered single point failures, both these devices are passive and 11 have a very high reliability rate.
12 In the normal scanning mode, antenna 13 switch 400 would connect power supply 10 to circulator 14 port A. Single pole, single throw switch 415 would be closed so that the circulator would transfer power 16 from port A to port C which is connected to power 17 divider 403. During normal operation of the auxiliary 18 mode, antenna switch 400 would connect power supply 10 19 to first data antenna 410. During back-up operation in the scanning mode, power supply 20 would be 21 connected to power divider 403 via antenna switch 401 22 and circulator 402. Switch 415 would be open so that 23 the circulator would view port A as an open circuit 24 and would transfer the power supplied to port B to port C by bypassing port B. In the back-up auxiliary 26 mode, antenna switch 401 would interconnect second 27 data antenna 411 to power supply 20.
~ 3 ~ 2 1 A short circuit failure of` switch 415 does 2 not cause a signal critical failure because it 3 continues -to connect primary power source 10 to power 4 divider 403 via circulator 402. An open circuit f`ailure of switch 415 would automatically cause 6 switchover to the back up supply 20 which in fact 7 requires an open circuit switch 415 to transfer the 8 amplified carrier to the array power divider 4û3.
9 Therefore, the combination of circulator 402 and switch 415 provide a fail-operational configuration.
11 Figure 6 illustrates another alternative 12 embodiment of the invention wherein circulator 402 is 13 used in the same manner as Figure 5 to alternatively 14 connect the signal sources to power divider 403. In addition, second switching array 170 and third switch 16 array 131 are used as described above.
17 While there have been described what are 18 at present considered to be the preferred embodiments 19 of this invention, it will be obvious to those skilled in the art that various changes and modifications may 21 be made therein without departing from the invention 22 and it is, therefore, aimed to cover all such changes 23 and modifications as fall within the true spirit and 24 scope of the invention.
8 2. Description of the Prior Art 9 Antenna techniques are known which lû use the phased array scanning beam antenna of a 11 microwave landing system (MLS) to broaden its 12 radiation pattern to satisfy the data antenna 13 requirements. Such techniques generally employ phase 14 spoiling of the phased array aperture. The fundamental limitation of this technique is that it 16 cannot provide the out-of-coverage indications (OCI) 17 signals and the 360 data signals without employing 18 a single thread multiple port rf switch. This 19 technique is deficient because it is subject to slngle point failures within the phased array which can cause 21 substantial radiation pattern minima when used in the 22 data antenna mode (low gain - broad pattern). These 23 minima are very difficult, if not practically 24 impossible, to monitor and detect. In addition, single point system failures also exist and can create 1 3 ~ 2 1 significant sa-~ety risks in certain operational 2 scenarios.
3 The MLS signal format requires multiple 4 antenna functions to provide the signals over wide coverage sect.ors. The format also provides -for signal 6 transmission outside the normal coveraqe volume, e.g., 7 out-of-coverage indication signals (ûCI). Inherent 8 growth capabilities in the system such as 360 data 9 link coverage, also require additional antennas in many practical applications. Because of the multiple 11 antennas required for MLS, an antenna switch is used 12 to connect a transmitter sequentially in time to each 13 antenna port. Although redundant transmitters and 14 control electronics can be enacted on line to provide signal continuity in the event of a failure, the 16 switching components (rf and logic) are a limiting 17 factor in supporting the requirements for signal 18 continuity in high reliability applications.
It is an object of this invention to 21 provide an MLS employing redundant rf switching of 22 dual signal sources to minimize the effect of switch 23 failures.
24 It is another object of this invention to provide an MLS system with dual signal sources ~31~62 1 connected to a primary element array via a passive 2 circulator and switch cornbination which perrnits 3 continued operation even during failure (i.e.
4 fail-operational).
It is ano-ther object of this invention to 6 provide an MLS system with rf and beann steering logic 7 switch arrays for eliminating single point failures.
8 It is another object of this invention to 9 provide a microwave landing system with a recombining network and switch array for driving auxiliary wide 11 sector antennas with fail-soft performance.
12 The antenna system according to the 13 invention radiates wave energy signals into a selected 14 region of space and in a desired radiation pattern.
The system includes means for supplying wave energy 16 signals and a primary aperture comprising an array of 17 primary antenna elements. An auxiliary aperture 18 comprising an array of auxiliary antennas is also 19 provided. Recombining means may be used for recombining supplied wave energy signals and for 21 supplying the recombined signals to the auxiliary 22 aperture. First means phase shifts the supplied wave 23 energy signals. Second means selectively couples 24 phased signals provided by the first means to either the primary antenna elements or to the recombining 26 means. The first means provides a beam radiated by ~ 3 ~
1 the primary array in accordance with a predeterrnined 2 pattern when said second means couples phased signals 3 to the primary array. The second means also provides 4 a beam which is radiated by at least one of the auxiliary antennas when the first means couples 6 supplied wave energy signals to the recombining means.
7 The means for supplying may be comprised 8 of means for supplylng first wave energy signals and 9 means for supplying second wave energy signals. The means for supplying second wave energy signals is 11 independent of the means for supplying first wave 12 energy signals. Third means selectively couples one 13 of either the first wave energy signals or the second 14 wave energy signals to the first means. The first means may be comprised of an array of phase shifters, 16 a first beam steering unit for controlling the phase 17 shifters and a second beam steering unit, independent 18 of the first beam steering unit, for controlling the 19 phase shifters. Fourth means selectively couples one 2û of either the first beam steering unit or the second 21 beam steering unit to the array of phase shifters.
22 For a better understanding of the present 23 invention, together with other and further objects, 24 reference is made to the following description, taken in conjunction with the accompanying drawings, and its 26 scope will be pointed out in the appended claims.
~31~2 2 Figure 1 is a block diagram of a microwave 3 landing sys-tem (MLS) according tû the invention 4 including dual signal sources and a recombining network for driving auxiliary antennas.
6 Figure 2 is a detailed block diagram of 7 one preferred embodiment of the MLS illùstrated in 8 Figure 1.
9 Figure 3 is a schematic illustration of a Butler matrix for use as a recombining network 11 according to the invention.
12 Figure 4 is a functional block diagram of 13 a microwave landing system (MLS) according to the 14 invention including dual signal sources and antenna switches for supplying dual auxiliary antennas.
16 Figure 5 is a functional block diagram of 17 an MLS according to the invention including dual 18 signal sources fed through a circulator and antenna 19 switches for supplying dual auxiliary antennas.
Figure 6 is a functional block diagram of 21 an MLS according to the invention including dual 22 signal sources fed through a circulator and a 23 recombining network for driving auxiliary antennas.
, 1 DETAILED DESCRIPTION OF Tl-lE INVENTION ~ g ~2 .
2 The standards specified by the Federal 3 Aviation Administration and the International Civil 4 Aviation Organization (ICAO) define the operational reliability requirements for the various levels of 6 MLS. The mûst reliable level defined by the standards 7 is known as category IIIo In category III systems it 8 is necessary to have redundant operation of various 9 subsystems in order to meet the operational lû requirements and avoid a break in the signal 11 continuity because of critical failures. The MLS
12 signal format requires multiple antenna functions to 13 provide the signals over the nominal coverage limits.
14 The format also provides for signal transmission outside the normal coverage volume, for example, ûCI -16 out-of-clearance indication. Inherent growth 17 capabilities in the system, such as 36û data 18 transmission, also require additional antennas in 19 practical applications. The multiple antennas 2û required for MLS result in the use of antenna switches 21 for connecting the transmitter sequentially in time to 22 each antenna port. Redundant transmitters and control 23 electronics can be employed on line to provide signal 24 continuity in the event of a failure. However, a switching component (rf and logic) is a fundamental 26 aspect which cannot be practically duplicated. This 1 presen-ts a limiting factor in supportinq the 13 ~ 2 2 requirements for signal continuity in Category III
3 applications.
4 In accordance with the invention, this dependency on the need to use a switching component to 6 connect auxiliary antennas may be minimized by using a 7 recombining network. rhe network recombines the power 8 which would have been radiated by each element in the 9 phased array of the primary aperture. The power is lû recombined into a multiplicity of beam ports which are 11 connected to auxiliary antennas such as data antennas, 12 OCI antennas, clearance antennas and C-Band 13 synchronization antennas. The technique employs a 14 single-pole, double-throw (SPDT) switching component at the output of each phase shifter in the array in 16 order to create a switch mechanism which is inherently 17 redundant and which fails soft.
18 Furthermore, it is necessary to have 19 independent, redundant transmitters and beam steering units (BSUs) in order to meet operational 21 requirements. In the past, such transmitters and BSUs 22 were each connected through a single switch so that 23 when one ~ailed, the other would be selected. An 24 inherent flaw in this connection approach is that even though the transmitters and BSUs are redundant, the 26 switch is not and a switch failure results in a 1 critical system failure. The invention distributes 2 the switching of the redundant transmitters and of the 3 BSUs so that such switching is not dependent on any 4 one switch. Alternatively, a circulator and switch may be used to link the redundant transmitter to the 6 phased array in a fail-operational confiquration.
7 Referring to Figure 1, the redundant 8 transmitters are illustrated by the first signal 9 source lû and second signal source 2û which is lû independent of the first signal source 10. The first 11 signal source 10 provides its signal via line 30 to 12 first power divider 40 which distributes the signal to 13 various outputs 51, 52, 53, 54 of the first power 14 divider 40. Similarly, second signal source 20 provides its signal via line 6û to second power 16 divider 70 which distributes the provided signal to 17 its various outputs 81, 82, 83, 84. The outputs of 18 power dividers 40 and 70 are provided to a first 19 switch array 90.
Switch array 90 is a group of single-pole, 21 double-throw switches 100. Each SPDT switch 100 has 22 inputs 101 and 102 with a single output 103. The 23 position of each switch is controlled by either the 24 main beam steering unit (BSU) 150 or standby BSU 140.
Generally, each input 101 of each SPDT switch 100 26 would be connected to one of the outputs 51, 52, 53, ~31~ 2 1 54 of ~irst power divide:r 40. The correspondinq input 2 102 of SPDT switch 100 would be connected ko one of 3 the corresponding outputs 81, 82, 83, 84 of second 4 power divider 70. In normal operation, the firs-t signal source would be selected and would provide 6 power to the system via the first power divider 40 and 7 all SPDT switches 100 would be in the UP position so 8 that each input 101 would be connected to switch 9 output 103. Upon detection of a failure in the first signal source 10, BSU 150 would operate the SPDT
11 switches 100 via control 104 and move each switch 100 12 to the DOWN position so that input 102 would be 13 connected to switch output 103. This would result in 14 the second signal source 20 via power divider 70 providing the necessary rf power to the MLS. As a 16 result, failure of one of the SPDT switches 100 does 17 not totally disable the MLS and would only affect the 18 particular port through which the failed switch is 19 connected.
The outputs of first switch arra~/ 90 are 21 connected to phase shifter array 120 for controlling 22 the scanning of the radiated beam in response to 23 controls provided by either BSU 130 or standby BSU 140 24 via third switch array 131. Switch array 131 is a group of single polej double throw switches 132. Each 26 SPDT switch 132 has inputs 133, 134 with a single ~ 3 ~
1 output 135. The position of each switch is controlled 2 by either the main BSU 13û or standby BSU 14û.
3 Generally, each input 133 of each SPDT switch 132 4 would be connected to one of the outputs of main BSU
13û. The corresponding input 134 of SPDT switch 132 6 would be connected to one of the corresponding outputs 7 of standby BSU 14û. In normal operation, the main BSU
8 130 would be selected and would provide control 9 signals to phase shifter array 120. All SPDT switches 132 would be in the LEFT position so that each input 11 133 would be connected to switch output 135. Upon 12 detection of a failure of the main BSU 130, monitor 13 and switchover logic 150 would operate the SPDT
14 switches 132 and move each to the RIGHT position so that input 134 would be connected to switch output 16 135. This would result in the standby BSU 14û
17 providing control signals to phase shifter array 120.
18 As a result, failure of any one of the SPDT switches 19 132 does not create a single point system failure and cannot totally disable the MLS. A switch failure 21 woùld only affect the particular phase shifter with 22 which the failed switch is associated.
23 Generally, control of the system operation 24 would be un~er main BSU 13û in coordination with monitor and switchover logic 150. Logic 150 is 26 constantly analyzing various monitor outputs provided ~ 3 ~
1 by one or more rnonltors (not shown). As shown in 2Figure 1, each BSU 1~0, 140 controls ~he first switch 3 array 9û, the second switch array 170 (described 4 below) and the third switch array 131. The controls are illustrated in this manner because, as shown in 6 Figure 2, this facilitates a modular configuration.
7 There may also be a requirement for redundancy (not 8 illustrated) with regard to monitors 15û.
9The outputs from phase shifter array 12û
lû which include phase shifted signals are then provided 11 via distributed amplifier array 160 to second switch 12 array 17û. Amplifier array 160 is a plurality of 13 in-line amplifiers, one for each output port of the 14 phase shifter array 120. Switch array 17û is a group of single pole, double throw switches 180. Each 16 switch has an input 181 and two outputs 182, 183.
17 Each output 182 is connected to a corresponding 18 element of the primary element array 190 to power the 19 primary antenna elements for providing a scanning MLS
2û beam. Each output 183 is connected to the 21 corresponding input of recombining network 2ûO for 22 powering the auxiliary antenna elements. The position 23 of each SPDT switch 180 of second switch array 170 is 24 controlled by BSU 130 or BSU 140 via third switch array 131. In the DOWN position, each SPDT switch 180 26 powers the primary element array l9û via output 183.
-12~
~ 3 ~ 2 1 In the UP position, each SPDT switch 180 powers the 2 recombining network 200 via output 182.
3 As with the -firs-t switch array 9û, the 4 second switch array permits supplied energy signals to be either supplied to the primary element array l9û or 6 to the auxiliary element array 21û without the 7 supplying of such signals being dependent upon any one 8 single-pole, double-throw switch or being subject to 9 any single point failure.
lû An MLS generally has several modes o-f 11 operation. In one mode, a Tû-FR0 beam is scanned in 12 order to provide aircraft within the scanning beam 13 azimuth or elevation information. In other modes of 14 operation, auxiliary antennas radiate signals which provide supplemental landing information. Primary 16 element array 190 includes a plurality of antenna 17 elements which, when supplied by wave energy signals, 18 provide a beam of radiated energy. The beam is 19 electronically scanned Tû and FR0 by varying the phase 2û of the input signals to the antenna elements. The 21 phase is varied by phase shifters 120.
22 During auxiliary operationJ one or more 23 auxiliary antennas radiate information. Auxiliary 24 element array 210 is a grouping of various auxiliary antennas which are used to provide the supplemental 26 information to aircraft within the range of the MLS.
~ 3 ~
1 In the prior art, auxiLiary antennas are generally 2 powered directly by the siqnal source. As indicated 3 abûve, an antenna switch is used to select the 4 particular antenna or group of antennas which are connected to the signal source. As a result, the 6 reliability of the auxiliary antenna operation is 7 dependent upon the single antenna switch which selects 8 the antenna and connects it to the signal source.
9 In contrast, the invention employs a second switch array 17û which supplies power to a 11 recombining network 2ûû to feed the auxiliary element 12 array 210. During auxiliary operation of the MLS, 13 each SPDT switch 180 is in the DOWN position so that 14 supplied signals are provided to recombining network 2ûû. The number of inputs to recombining network 2ûO
16 equals the number of inputs to primary element array 17 110. The number of outputs for recombining network 200 18 depends upon the number of elements in the auxiliary 19 element array and may be, for example, four or eight.
2û Recombining network 20û is any standard network, such 21 as a Blass or Butler array, which recombines the 22 signals at the input according to a predetermined 23 coupling arrangement and provides the combined signals 24 at the outputs of the network 200.
During auxiliary operation, the beam 26 steering unit 130 controls the phase shifters 120 so $ ~ 2 1 -that the phase o~ the signals input into the 2 recombining network 2ûû result in illuminating the 3 partlcular output of network 200 which is connected to 4 the particular auxiliary antenna of array 210. For example, assume that the OCI auxiliary antenna mus-t be 6 illuminated. Also, assume that the ûCI antenna is 7 connected to the first output port of recombining 8 network 2ûO. Since the characteristics of the 9 recombining network are known and the coupling lû arrangement within the network preset, appropriate 11 illumination of the inputs of network 20û will result 12 in output 1 being primarily illuminated. In this way, 13 the operation of each auxiliary antenna is not 1~ dependent on any single antenna switch.
Figure 2 illustrates one preferred 16 embodiment of the invention of Figure 1. Dual signal 17 sources 300 and 301 separately feed dual power 18 dividers 302, 3û3. In particular, a first transmitter 19 (TXl) feeds the first power divider 302 and a second transmitter (TX2) feeds the second power divider 303.
21 The outputs of each of the power dividers is connected 22 to the input to one of the modules 305-308 which 23 includes a single pole, double throw switch 3û5a-308a, 24 a phase shifter 305b-308b, a second single pole, double throw switch 305c-308c and a third single pole, 26 double throw switch 3û5d-3û8d. Modules 3û5-308 ~15-~ 3~ '2 1 comprise the combination o~ ~irst switch array 90, 2 phase shifters 120, second switch array 170 and third 3 switch array 131 as illustrated in Figure 1. Main ~SU
4 bus 311 provides the control signals between main BSU
309 and each of the SPDT switches. Main BSU bus 311 6 also provides one of the input signals to SPDT
7 305d-3û8d. Standby BSU bus 312 provides switch 8 control signals and the other input signal to SPDT
9 305d-308d. For simplicity, connectors to the switches lû from the BSUs are illustrated as buses. However, each 11 SPDT may be directly connected to a separate port of 12 the BSU.
13 Single pole, double throw switches 14 305a-308a correspond to the first switch array 90 of Figure 1. Switches 305c-308c correspond to the second 16 switch array 170. Switches 3û5d-308d correspond to 17 the third switch array 131. Phase shifters 305b-308b 18 correspond to phase shifter array 120. Amplifiers 19 3û5e-308e correspond to the distributed amplifier array 160. Elements 33û-333 correspond to the primary 21 element array 19û.
22 ûperation of the preferred embodiment 23 illustrated in Figure 2 is as follows. During 24 scanning cycles, main BSU 309 instructs the switches via bus 311. Switches 305a-308a are placedjin the UP
26 position, switches 305c-308c are placed in the ûOWN
~ 3 ~ 2 1 position and switches 305d-308d are olaced ir~ the UP
2 position. This results in transmitter 300 providing 3 signals via the first power divider 302 to -the primary 4 antenna elements 33û-333. In addition, phase shifters 305b-308b receive control signals frorn the main BSU
6 309 via bus 311 which result in the scanning of the 7 beam ra~iated by elements 33û-333. During auxiliary 8 modes, main BSU 309 would place switches 305c 308c in 9 the UP position. This would result in supplied wave energy signals being provided to recombining network 11 350. In addition, main BSU 317 would control phase 12 shifters 305b-308b so that the phased signals being 13 provided to recombining network 350 would illuminate 14 the appropriate auxiliary antenna port. This aspect of the invention is described in more detail below.
16 In contrast, during scanning modes, main BSU is 17 adjusting the phase shifter 3û5b-308b to radiate a 18 scanning beam via the primary array of elements 1~ 330-333.
In the event of a failure, monitor and 21 switchover logic 320 would evaluate the failure and 22 correct the problem. Logic 320 may be advised of a 23 failure via field monitors, inherent monitors within 24 the system, information derived from built in test equipment or from information provided by external 26 sources. For example, if prlmary signal source 3ûO
1 were inoperative, main BSU 309 would instruct SPDT
2 switches 305a-308a -to switch to the DOWN position.
3 This instruction would be provided via main bus 311 so 4 that power divider 303 would be supplying the input signals via secondary source 301. If a failure in the 6 main beam steering unit 317 is detected, standby BSU
7 310 controls switches 305d-308d and places the 8 switches in the DOWN position so that standby BSU 310 9 is providing control signals via bus 312 to phase shifters 305b-308b.
11 Figure 3 illustrates one embodiment of 12 recombining network 350 in the form of a Butler 13 (factorial) array matrix having 100% circuit 14 efficiency. Recombining network 350 has input ports 1, 2, 3 and 4, linked by phase shifters 351 and 16 couplers Cll, C12, C13, C21 and C22 to 17 output ports A and B. This forms a four element, two 18 beam matrix. Providing signals of phase Ell, E12, 19 E13 and E14 to input ports 1-4, respectively, will result in illuminating output port A. On the other 21 hand, providing signals of phase E21, E22, E23 22 and E24 to input ports 1-4, respectively, will 23 result in illurnination of the output port B. For a 24 more detalled description of the operation of such arrays see Microwave Scanning Antennas edited by R. C.
26 Hansen, Chapter 3, Academic Press, 1966.
1 For example, a data antenna rnay be ~ 3~ ~g 6 2 connected to output port A and an OCI antenna to 3 output port B. During ûCI cycles, main BSU places 4 switches 305c-308c in the UP position and provides signals to the input ports l-ll having phases E21, 6 E22, E23 and E24, respectively. During data 7 cycles, main BSU 309 places switches 305c-308c in the 8 UP position and provides signals to the input ports 9 1-4 of recombining network 350 at the phases Ell, E12, E13, E14, respectively. This results in 11 illumination of only port A and transmission of such 12 information by the data antenna. The selection of the 13 data and OCI antennas, therefore, does not depend upon 14 any single rf switch.
Figures 4, 5 and 6 illustrate various 16 alternative embodiments of the invention. The same 17 reference characters have been used for the same 18 structure which appears in Figures 1, 4, 5 and 6.
19 In Figure 4, the recombining network becomes unnecessary if the data antenna is the only 21 auxiliary antenna which is considered critical to the 22 operation of the system. Antenna switch 400 is 23 located between power source 10 and first power 24 divider 40. A second antenna switch 401 is located between power source 20 and second power divider 70.
26 During auxiliary modes of operation, the controlling ~ 3 ~ 2 1 beam steering unit activates the apPrOpriate antenna 2 switch to provide a signal for radiation by the 3 selected data antenna. Durinq normal operation in the 4 scanning mode, antenna switch 4ûO would connect pûwer supply lû to first power divider 40. During normal 6 operation in the auxiliary mode, antenna switch 400 7 would connect power supply 10 to first data antenna 8 411. During the back-up scanning mode, antenna switch 9 401 would connect power supply 20 to second power lû divider 70. During back-up operation of the auxiliary 11 mode, power supply 20 would be connected to second 12 data antenna 411 via antenna switch 401. In Figure 4, 13 main BSU 130 is shown as having control bus 412 14 connected to phase shifter array 120, first switch array 90 and antenna switches 400 and 401 to control 16 the operation of these subsystems. Similarly, standby 17 BSU 140 is connected by standby bus 413 to the same 18 subsystems. Alternatively, the main BSU 130 and 19 standby BSU 140 may be connected to the subsystems via a third switch array as illustrated in Figure 1 or by 21 an array of OR gates or other logic circuits which 22 would function as switches.
23 Figure 5 illustrates another alternative 24 embodiment of the invention in which a passive ferrite circulator 402 is used to interconnect the alternative 26 power sources to power divider 403. Circulator 402 is 1 a standard passive ferrumagrlekic device such as a 2 passive waveguide junction. Each port A, B, C of 3 circulator 402 is -related to the other such that when 4 power is fed to any one port, it is transferred to the next port as indicated by the arrow. The invention as 6 illustrated in Figure 5 would be useful when it is 7 unnecessary to employ switching arrays such as 8 switching array 90, 131 or 170. Although circulator 9 402 and power divider 403 can be considered single point failures, both these devices are passive and 11 have a very high reliability rate.
12 In the normal scanning mode, antenna 13 switch 400 would connect power supply 10 to circulator 14 port A. Single pole, single throw switch 415 would be closed so that the circulator would transfer power 16 from port A to port C which is connected to power 17 divider 403. During normal operation of the auxiliary 18 mode, antenna switch 400 would connect power supply 10 19 to first data antenna 410. During back-up operation in the scanning mode, power supply 20 would be 21 connected to power divider 403 via antenna switch 401 22 and circulator 402. Switch 415 would be open so that 23 the circulator would view port A as an open circuit 24 and would transfer the power supplied to port B to port C by bypassing port B. In the back-up auxiliary 26 mode, antenna switch 401 would interconnect second 27 data antenna 411 to power supply 20.
~ 3 ~ 2 1 A short circuit failure of` switch 415 does 2 not cause a signal critical failure because it 3 continues -to connect primary power source 10 to power 4 divider 403 via circulator 402. An open circuit f`ailure of switch 415 would automatically cause 6 switchover to the back up supply 20 which in fact 7 requires an open circuit switch 415 to transfer the 8 amplified carrier to the array power divider 4û3.
9 Therefore, the combination of circulator 402 and switch 415 provide a fail-operational configuration.
11 Figure 6 illustrates another alternative 12 embodiment of the invention wherein circulator 402 is 13 used in the same manner as Figure 5 to alternatively 14 connect the signal sources to power divider 403. In addition, second switching array 170 and third switch 16 array 131 are used as described above.
17 While there have been described what are 18 at present considered to be the preferred embodiments 19 of this invention, it will be obvious to those skilled in the art that various changes and modifications may 21 be made therein without departing from the invention 22 and it is, therefore, aimed to cover all such changes 23 and modifications as fall within the true spirit and 24 scope of the invention.
Claims (39)
- Claim 1. An antenna system for radiating wave energy signals into a selected region of space and in a desired radiation pattern, said system comprising:
(a) an aperture comprising an array of antenna elements;
(b) first means for supplying a plurality of first wave energy signals;
(c) second means, independent of said first means, for supplying a like plurality of second wave energy signals substantially the same as said first wave energy signals;
(d) third means for selectively coupling either said plurality of first wave energy signals or said plurality of second wave energy signals to the antenna elements; and (e) fourth means for scanning a beam radiated by the array in accordance with a predetermined pattern, said beam resulting from the supplied wave energy signals coupled to the antenna elements. - Claim 2. The antenna system of claim 1 wherein the aperture comprises a primary aperture comprising a primary array of primary antenna elements and an auxiliary aperture comprising an auxiliary array of auxiliary antenna elements; further including recombining means for recombining a plurality of supplied wave energy signals and for supplying the recombined signals to the auxiliary aperture; said fourth means comprising means for phase shifting a plurality of supplied wave energy signals; and further including fifth means for selectively coupling said plurality of phased signals to either the primary antenna elements or the recombining means.
- Claim 3. The antenna system of claim 2 wherein said third means comprises a first array of switches, each said switch having outputs associated with the first means, each said switch having first and second inputs; the first input coupled to the means for supplying a plurality of first wave energy signals; the second input coupled to the means for supplying a plurality of second wave energy signals.
- Claim 4. The antenna system of claim 3 wherein said recombining means comprises a recombining network having a plurality of inputs equal to the number of primary antenna elements and having outputs, each one connected to only one of the auxiliary antenna.
- Claim 5. The antenna system of claim 4 wherein said fourth means comprises:
an array of phase shifters;
a first beam steering unit for controlling said phase shifters;
a second beam steering unit for controlling said phase shifters; and sixth means for selectively coupling one of either said first beam steering unit or said second beam steering unit to said array of phase shifters. - Claim 6. The antenna system of claim 5 wherein said sixth means comprises a second array of switches, each said switch having outputs coupled to a control port of a phase shifter of the array of phase shifters, each said switch having first and second inputs; the first input being coupled to the first beam steering unit and the second input being coupled to the second beam steering unit.
- Claim 7. The antenna system of claim 6 further including means for amplifying each of the supplied wave energy signals provided by the fourth means.
- Claim 8. The antenna system of claim 7 wherein said means for amplifying comprises a distributed array of amplifiers, one associated with each of -the supplied wave energy signals provided by the fourth means, said amplifiers for amplifying the associated signal.
- Claim 9. The antenna system of claim 1 further including means for amplifying each of the supplied wave energy signals provided by the fourth means.
- Claim 10. The antenna system of claim 9 wherein said means for amplifying comprises a distributed array of amplifiers, one associated with each of the supplied wave energy signals provided by the fourth means, said amplifiers for amplifying the associated signal.
- Claim 11. The antenna system of claim 1 wherein said fifth means comprises a third array of switches, each said switch having inputs coupled to the first means; each said switch having first and second outputs, the first output being coupled to a corresponding primary antenna element and the second output being coupled to a corresponding input of the recombining means.
- Claim 12. The antenna system of claim 11 wherein said first means for supplying wave energy signals comprises a first signal source and a first power divider associated therewith and said second means for supplying wave energy signals comprises a second signal source, independent of said first signal source, and a second power divider associated therewith.
- Claim 13. The antenna system of claim 2 wherein said fifth means comprises a third array of switches, each said switch having inputs being coupled to the first means; each said switch having first and second outputs, the first output being coupled to a corresponding primary antenna element and the second output being coupled to a corresponding input of the recombining means.
- Claim 14. The antenna system of claim 1 wherein said third means comprises a first array of switches, each said switch having outputs associated with the first means, each said switch having first and second inputs; the first input being coupled to the means for supplying first wave energy signals; the second input being coupled to the means for supplying second wave energy signals.
- Claim 15. The antenna system of claim 14 wherein said recombining means comprises a recombining network having a plurality of inputs equal to the number of primary antenna elements and having outputs, each one coupled to only one of the auxiliary antenna.
- Claim 16. The antenna system of claim 1 wherein said fourth means comprises:
an array of phase shifters, each having a central port;
a first beam steering unit for controlling said phase shifters;
a second beam steering unit for controlling said shifters; and sixth means for selectively coupling either said first beam steering unit or said second beam steering unit to the control ports of said phase shifters. - Claim 17. The antenna system of claim 16 wherein said sixth means comprises a second array of switches, each said switch having an output coupled to a control port of a corresponding phase shifter of the array of phase shifters, each said switch having first and second inputs; the first input being coupled to the first beam steering unit and the second input being coupled to the second beam steering unit.
- Claim 18. The antenna system of claim 1 further comprising:
first and second auxiliary apertures;
seventh means for selectively coupling said first wave energy signals to said first auxiliary aperture; and eighth means for selectively coupling said second wave energy signals to said second auxiliary aperture. - Claim 19. The antenna system of claim 18 wherein said first auxiliary aperture comprises a first data antenna; said second auxiliary aperture comprises a second data antenna; said fourth means comprises a first antenna switch coupled between said first means and said third means for selectively coupling said first wave energy signals to said first data antenna; and said fifth means comprises a second antenna switch coupled between said second means and said third means for selectively coupling said second wave energy signals to said second data antenna.
- Claim 20. The antenna system of claim 19 wherein said third means comprises a circulator having a first input coupled to the first antenna switch for receiving said first wave energy signals and having a second input coupled to the second antenna switch for receiving said wave energy signals and having an output; and further comprising a power divider having an input coupled to the output of the circulator and having outputs associated with said aperture.
- Claim 21. The antenna system of claim 19 wherein said third means comprises a first array of switches, each said switch having an output associated with the first means, each said switch having first and second inputs; the first input being coupled to the means for supplying first wave energy signals; the second input being coupled to the means for supplying second wave energy signals.
- Claim 22. The antenna system of claim 21 wherein said fifth means comprises a third array of switches, each said switch having an input coupled to the first means; each said switch having first and second outputs, the first output being coupled to a corresponding primary antenna element and the second output being coupled to a corresponding input of the recombining means.
- Claim 23. The antenna system of claim 1 wherein said third means comprises a circulator having a first input coupled to the first means for receiving said first wave energy signals and having a second input coupled to the second means for receiving said wave energy signals and having an output; and further comprising a power divider having an input coupled to the output of the circulator and having outputs associated with said aperture.
- Claim 24. An antenna system for radiating wave energy signals into a selected region of space and in a desired radiation pattern, said system comprising:
(a) means for supplying a plurality of wave energy signals;
(b) a primary aperture comprising a primary array of primary antenna elements;
(c) an auxiliary aperture comprising an auxiliary array of auxiliary antennas;
(d) recombining means for recombining supplied wave energy signals and for supplying the recombined signals to the auxiliary aperture;
(e) first means for phase shifting supplied wave energy signals;
(f) second means for selectively coupling said phase shifted wave energy signals provided by the first means to only one of either the primary antenna elements or the recombining means;
(g) said first means providing a beam radiated by the primary array in accordance with a predetermined pattern when said second means couples said phase shifted signals to the primary array; and (h) said first means providing a beam radiated by at least one of said auxiliary antennas when said second means couples said phase shifted signals to said recombining means. - Claim 25. The antenna system of claim 24 wherein said recombining means comprises a recombining network having a plurality of inputs equal to the number of primary antenna elements and having outputs, each one connected to only one of the auxiliary antennas.
- Claim 26. The antenna system of claim 24 wherein said means for supplying comprises:
means for supplying a plurality of first wave energy signals;
means for supplying a like plurality of second wave energy signals substantially the same as said plurality of first wave evergy signals; and third means for selectively coupling either said plurality of first wave energy signals or said plurality of second wave energy signals to said first means. - Claim 27. The antenna system of claim 26 wherein said third means comprises a first array of switches, each said switch having an output coupled to the first means, each said switch having first and second inputs; the first input being coupled to the means for supplying first wave energy signals; the second input being coupled to the means for supplying second wave energy signals.
- Claim 28. The antenna system of claim 24 wherein said first means comprises:
an array of phase shifters, each having a control port;
a first beam steering unit for controlling said phase shifters;
a second beam steering unit for controlling said shifters; and fourth means for selectively coupling either said first beam steering unit or said second beam steering unit to the control ports of said phase shifters. - Claim 29. The antenna system of claim 28 wherein said fourth means comprises a second array of switches, each said switch having an output coupled to a control port of a phase shifter of the array of phase shifters, each said switch having first and second inputs; the first input being coupled to the first beam steering unit and the second input being coupled to the second beam steering unit.
- Claim 30. The antenna system of claim 24 wherein said second means comprises a third array of switches, each said switch having an input coupled to the first means; each said switch having first and second outputs, the first output being coupled to a corresponding one of said primary antenna elements and the second output being coupled to a corresponding input of said recombining means.
- Claim 31. The antenna system of claim 30 wherein said means for supplying comprises:
means for supplying a plurality of first wave energy signals;
means for supplying a like plurality of second wave energy signals; and third means for selectively coupling either said first wave energy signals or said second wave energy signals to said first means. - Claim 32. The antenna system of claim 31 wherein said first means comprises:
an array of phase shifters, each having a control port;
a first beam steering unit For controlling said phase shifters;
a second beam steering unit for controlling said shifters; and fourth means for selectively coupling either said first beam steering unit or said second beam steering unit to the control ports of said phase shifters. - Claim 33. The antenna system of claim 32 wherein said recombining means comprises a recombining network having a plurality of inputs equal to the number of primary antenna elements and having outputs, each one coupled to a corresponding one of the auxiliary antennas.
- Claim 34. The antenna system of claim 33 wherein said third means comprises a first array of switches, each said switch having an output coupled to the first means, each said switch having first and second inputs; the first input being coupled to the means for supplying first wave energy signals; the second input being coupled to the means for supplying second wave energy signals.
- Claim 35. The antenna system of claim 34 wherein said fourth means comprises a second array of switches, each said switch having an output coupled to a control port of a phase shifter of the array of phase shifters, each said switch having first and second inputs; the first input being coupled to the first beam steering unit and the second input being coupled to the second beam steering unit.
- Claim 36. The antenna system of claim 35 further including means for amplifying each of the phase shifted, supplied wave energy signals provided by the first means.
- Claim 37. The antenna system of claim 36 wherein said means for amplifying comprises a distributed array of amplifiers, one associated with each of the phase shifted, supplied wave energy signals provided by the first means, said amplifiers for amplifying the associated signals.
- Claim 38. The antenna system of claim 24 further including means for amplifying each of the phase shifted, supplied wave energy signals provided by the first means.
- Claim 39. The antenna system of claim 38 wherein said means for amplifying comprises a distributed array of amplifiers, one associated with each of the phase shifted, supplied wave energy signals provided by the first means, said amplifiers for amplifying the associated signals.
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/049,741 US4837580A (en) | 1987-05-14 | 1987-05-14 | Microwave landing system with fail-soft switching of dual transmitters, beam steering and sector antennas |
| US07/049,741 | 1987-05-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1315862C true CA1315862C (en) | 1993-04-06 |
Family
ID=21961452
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000565878A Expired - Fee Related CA1315862C (en) | 1987-05-14 | 1988-05-04 | Microwave landing system with fail-soft switching of dual transmitters, beam steering and sector analysis |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4837580A (en) |
| EP (1) | EP0293099B1 (en) |
| JP (1) | JPS6478178A (en) |
| CA (1) | CA1315862C (en) |
| DE (1) | DE3878986T2 (en) |
| NO (1) | NO171620C (en) |
Families Citing this family (30)
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|---|---|---|---|---|
| JP2655409B2 (en) * | 1988-01-12 | 1997-09-17 | 日本電気株式会社 | Microwave landing guidance system |
| DE3810628C1 (en) * | 1988-03-29 | 1989-04-06 | Standard Elektrik Lorenz Ag, 7000 Stuttgart, De | |
| US4968982A (en) * | 1989-07-10 | 1990-11-06 | Hazeltine Corporation | Aircraft landing system having simplified out-of-coverage indication (OCI) |
| US5017927A (en) * | 1990-02-20 | 1991-05-21 | General Electric Company | Monopulse phased array antenna with plural transmit-receive module phase shifters |
| US5544347A (en) | 1990-09-24 | 1996-08-06 | Emc Corporation | Data storage system controlled remote data mirroring with respectively maintained data indices |
| EP0516265A1 (en) * | 1991-05-09 | 1992-12-02 | Siemens Plessey Electronic Systems Limited | Improvements in or relating to aircraft landing systems |
| EP0524327B1 (en) * | 1991-07-20 | 1996-06-05 | Alcatel SEL Aktiengesellschaft | Method for Monitoring and Controlling a Transmitting Station for a Position Locating System, particularly for the Microwave Landing System, and Transmitting Station for carrying out such method |
| DE4214338A1 (en) * | 1992-05-04 | 1993-11-11 | Thomson Brandt Gmbh | Vertical deflection circuit for a television receiver |
| US5543807A (en) * | 1992-11-25 | 1996-08-06 | Loral Corporation | Electronic commutation switch for cylindrical array antennas |
| WO1995006339A1 (en) * | 1993-08-20 | 1995-03-02 | Scan Tek, Inc. | High reliability fail-soft microwave landing system having high continuity of service and integrity |
| GB2304496A (en) * | 1995-08-17 | 1997-03-19 | Motorola Ltd | Coupling radio transmitters to antenna elements |
| US6438359B1 (en) * | 1996-07-19 | 2002-08-20 | Cellularvision Technology & Telecommunications, L.P. | Dual transmitter arrangement with back-up switching |
| FR2762937B1 (en) * | 1997-05-05 | 1999-06-11 | Alsthom Cge Alcatel | ACTIVE ANTENNA WITH RADIANT ELEMENTS NETWORK WITH REDUNDANT ARCHITECTURE |
| US6011512A (en) * | 1998-02-25 | 2000-01-04 | Space Systems/Loral, Inc. | Thinned multiple beam phased array antenna |
| US6377558B1 (en) * | 1998-04-06 | 2002-04-23 | Ericsson Inc. | Multi-signal transmit array with low intermodulation |
| JP2000244224A (en) * | 1999-02-22 | 2000-09-08 | Denso Corp | Multi-beam antenna and antenna system |
| US9485010B1 (en) | 2001-09-10 | 2016-11-01 | The Directv Group, Inc. | Adaptive coding and modulation for spot beam satellite broadcast |
| US7047029B1 (en) * | 2001-09-10 | 2006-05-16 | The Directv Group, Inc. | Adaptive transmission system |
| US7653349B1 (en) | 2003-06-18 | 2010-01-26 | The Directv Group, Inc. | Adaptive return link for two-way satellite communication systems |
| US20050176372A1 (en) * | 2004-02-05 | 2005-08-11 | Wheat International Communications Corporation | Highly integrated reliable architectural radio system for maritime application |
| US7741997B1 (en) * | 2005-08-17 | 2010-06-22 | Lockheed Martin Corporation | Multiple-beam phased array with switchable element areas |
| US9069070B2 (en) | 2012-06-01 | 2015-06-30 | Honeywell International Inc. | Systems and methods for the selection of antennas in aircraft navigation systems |
| TWI518993B (en) * | 2012-11-20 | 2016-01-21 | 財團法人工業技術研究院 | Multi-path switching system with adjustable phase shift array |
| CN103698778B (en) * | 2013-12-06 | 2016-01-06 | 上海卫星工程研究所 | Width phase difference signal generator |
| US9466866B2 (en) | 2014-04-08 | 2016-10-11 | Honeywell International Inc. | Systems and methods for using power dividers for improved ferrite circulator RF power handling |
| US9466865B2 (en) | 2014-04-08 | 2016-10-11 | Honeywell International Inc. | Systems and methods for improved ferrite circulator RF power handling |
| WO2018067779A1 (en) * | 2016-10-07 | 2018-04-12 | Honeywell International Inc. | Systems and methods for increasing capacity in a redundancy network |
| US10833408B2 (en) * | 2017-07-07 | 2020-11-10 | Rockwell Collins, Inc. | Electronically scanned array |
| TW202002401A (en) * | 2018-06-06 | 2020-01-01 | 財團法人工業技術研究院 | MIMO antenna system and controlling method thereof |
| US11381266B1 (en) * | 2020-12-31 | 2022-07-05 | Iridium Satellite Llc | Wireless communication with interference mitigation |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3964066A (en) * | 1975-01-02 | 1976-06-15 | International Telephone And Telegraph Corporation | Electronic scanned cylindrical-array antenna using network approach for reduced system complexity |
| US4186398A (en) * | 1975-06-09 | 1980-01-29 | Commonwealth Scientific And Industrial Research Organization | Modulation of scanning radio beams |
| US4037173A (en) * | 1976-07-27 | 1977-07-19 | Tull Aviation Corporation | Multiple carrier modulation synthesis |
| US4123759A (en) * | 1977-03-21 | 1978-10-31 | Microwave Associates, Inc. | Phased array antenna |
| US4178581A (en) * | 1978-11-03 | 1979-12-11 | The Bendix Corporation | Integrated antenna aperture |
| US4301533A (en) * | 1979-11-27 | 1981-11-17 | Bell Telephone Laboratories, Incorporated | Technique for increasing the rain margin of a TDMA satellite communication system |
| DE3226728A1 (en) * | 1982-07-16 | 1984-01-19 | ANT Nachrichtentechnik GmbH, 7150 Backnang | MICROWAVE SWITCH ARRANGEMENT WITH TRANSMITTER OR RECEIVER REPLACEMENT |
| FR2582127B1 (en) * | 1985-03-29 | 1994-05-20 | Thomson Csf | METHOD AND DEVICE FOR MONITORING A STATION OF AN MLS TYPE LANDING AID SYSTEM |
| DE3618628A1 (en) * | 1986-06-03 | 1987-12-10 | Standard Elektrik Lorenz Ag | MICROWAVE LANDING SYSTEM WORKING AFTER THE JET SWIVELING PROCESS |
-
1987
- 1987-05-14 US US07/049,741 patent/US4837580A/en not_active Expired - Fee Related
-
1988
- 1988-05-04 CA CA000565878A patent/CA1315862C/en not_active Expired - Fee Related
- 1988-05-05 EP EP88304078A patent/EP0293099B1/en not_active Expired - Lifetime
- 1988-05-05 DE DE8888304078T patent/DE3878986T2/en not_active Expired - Fee Related
- 1988-05-11 NO NO882063A patent/NO171620C/en unknown
- 1988-05-13 JP JP63116774A patent/JPS6478178A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| NO882063D0 (en) | 1988-05-11 |
| EP0293099B1 (en) | 1993-03-10 |
| JPS6478178A (en) | 1989-03-23 |
| NO171620B (en) | 1992-12-28 |
| US4837580A (en) | 1989-06-06 |
| DE3878986T2 (en) | 1993-06-17 |
| EP0293099A1 (en) | 1988-11-30 |
| NO171620C (en) | 1993-04-07 |
| DE3878986D1 (en) | 1993-04-15 |
| NO882063L (en) | 1988-11-15 |
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| Date | Code | Title | Description |
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| MKLA | Lapsed |