CN104181501B - Alignment system and localization method based on received terrestrial digital broadcasting TV signal - Google Patents
Alignment system and localization method based on received terrestrial digital broadcasting TV signal Download PDFInfo
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- CN104181501B CN104181501B CN201410414944.3A CN201410414944A CN104181501B CN 104181501 B CN104181501 B CN 104181501B CN 201410414944 A CN201410414944 A CN 201410414944A CN 104181501 B CN104181501 B CN 104181501B
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- 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
- G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
- G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
- G01S5/10—Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements, e.g. omega or decca systems
Abstract
A kind of high-accuracy position system based on ground digital television broadcast signal, including down coversion and sampling apparatus, fraction times time delay TDOA detection means, receiver location computing device and signal-to-noise ratio (SNR) estimation device；And localization method, including step：1. sampling obtains discrete signal；2. relevant treatment；3. detect that the signal arrival time difference and Different Ground digital TV transmitter signal in integral multiple sampling period reach the fraction times reaching time-difference of location receiver；4. merge and obtain the total time delay difference of signal；5. it is scaled distance and the coordinate setting of receiver is obtained by the geometrical relationship of coordinate.The present invention is under the superperformance and the characteristic of the low complex degree of system that ensure that integral multiple sub-sample cycle delay, decimal sampling cycle delay can be accurately obtained and limited so as to break through the error in a sampling period so that the precision of system is lifted again, by the detection to environment come in advance to the result progress estimation error and accuracy compensation of alignment system.
Description
Technical field：
High-precision reaching time-difference is carried out the present invention relates to one kind using ground digital television broadcast signal to extract, and
The method that high accuracy positioning is carried out using reaching time-difference, belongs to wireless communication technology field.
Background technology：
Reaching time-difference location technology (TDOA, Time Difference of Arrival), is a kind of wireless location skill
Art.The technology positioned different from the use of absolute time, TDOA technologies be by detect that the signal of two transmitting base stations reaches when
Between it is poor, rather than the absolute time reached determines to move the position of receiving platform, reduces time synchronized requirement.
TDOA location technologies are as a research direction of wireless location technology, and its technical characteristics is：TDOA technologies
Be passage time difference detected, when calculating TDOA values when, calculation error be all to all base stations identical and itself and be
Zero, these errors include public multipath error and clock synchronous error.
TDOA location technologies based on ground digital television broadcast, are that Different Ground numeral is extracted by broad sense cross-correlation
The reaching time-difference of television transmitter signal, so that it is determined that the position of location receiver.Because the precision of TDOA location technologies is straight
Connect depending on the precision for measuring the time difference, therefore the precision overwhelming majority of the TDOA location technologies based on ground digital television broadcast
It is determined by the precision for the time difference that broad sense cross-correlation is extracted.But be due to the time difference that broad sense cross-correlation is extracted be table
On the sub-sample cycle delay of present integral multiple, therefore for discrete data signal, broad sense cross-correlation extraction time is poor
Technology is only capable of accurately obtaining the delay in integral multiple sampling period, and shows the small several times time delay on signal phase simultaneously
Can not be easy and accurately detect.The limits of error system of this extraction time difference causes based on ground digital television broadcast
TDOA location technologies are unable to reach very high precision.
The content of the invention：
The problem of existing for prior art, it is a kind of based on ground digital television broadcast letter it is an object of the invention to propose
Number localization method and alignment system, can accurately detect decimal sampling cycle delay but not improve system complexity excessively,
So that receiving, function is quick, simple, time delay is accurately obtained, so as to improve the precision of positioning.
The present invention essential idea be：Ground digital television broadcast signal actually exists small several times during propagation
The delay in sampling period, but be due to be difficult to detect based on the related method of traditional time domain, so limiting based on ground number
The precision of the TDOA location technologies of word television broadcasting.The small several times for being difficult detection are postponed to change by the present invention using FIR filter
For signal after the processing that easily detects so that system can be not being examined accurately in the case of increase system complexity excessively
Measure the delay of signal.Additionally due to the nonlinear characteristic that the correlation peak of signal has with time delay, using linear
FIR filter can not accurately detect small several times delay, in order to obtain more accurate in the case of low computation complexity
As a result, adding certain delay in location receiver can be by the delay drop point of signal in relatively linear region, it is possible to both
The accurate and simple time delay for obtaining signal propagation, so that fast and accurately position receiver location.
The purpose of the present invention is realized by following technical scheme：
A kind of high-accuracy position system based on ground digital television broadcast signal, its feature is, including：Down coversion and
Sampling apparatus, the receiver location based on related fraction times time delay TDOA detection means, with data processing function calculate dress
Put and signal-to-noise ratio (SNR) estimation device；
The ground digital television broadcast signal received is switched to intermediate frequency simultaneously by described down coversion and sampling apparatus by radio frequency
Sampling is obtained after discrete signal, is transferred to the described fraction times time delay TDOA detection means based on correlation and is filled with signal-to-noise ratio (SNR) estimation
Put；
The described signal and known composition frame head that are received based on related fraction times time delay TDOA detection means
PN sequences carry out cross-correlation, and respectively detection integral multiple delay be delayed again with fraction, and fraction is delayed again calibrate after general
Two parts delay merges, and will obtain time delay difference and is transferred to receiver location computing device；
Described signal-to-noise ratio (SNR) estimation device, by estimating the signal to noise ratio received, is adaptively adjusted wave filter
Parameter, the offset that calculating is obtained is transferred to receiver location computing device；
Described receiver location computing device using each time difference of TDOA algorithm process and exports position coordinates, together
When the tv signal-noise ratio SNR that is detected according to signal-to-noise ratio (SNR) estimation device carried out come the deviation adaptively to time delay difference
Compensation correction, improves accuracy of detection.
Described is included based on related fraction times time delay TDOA detection means：Correlator, integral multiple time delay detection device, point
Detector, half integer multiple delay estimator and TDOA time delay combiners during several times；
Described correlator, the PN sequences of the ground digital television broadcast signal received and known composition frame head are entered
Row is related；
Described integral multiple time delay detection device, Detection and Extraction integral multiple time delay is carried out to correlated results；
Detector during described fraction times, carries out Detection and Extraction fraction times time delay, and will be based on PN sequences to correlated results
Related fraction is delayed conversion linear signal again；
Described half integer multiple delay estimator, for improving the estimated accuracy when fraction times time delay is less than 0.5 symbol；
Described TDOA time delay combiners, it is poor that integral multiple symbol delay time difference and fraction times symbol delay time are carried out
It is total to calculate the total time delay difference of signal.
It is a kind of to utilize the high-precision fixed of the high-accuracy position system progress based on ground digital television broadcast signal
Position method, it is characterised in that this method comprises the following steps：
1. ground digital television broadcast signal will be received intermediate frequency and sampling acquirement discrete signal is switched to by radio frequency；
2. the PN sequences of discrete signal and locally known composition frame head are subjected to relevant treatment, obtain their cross-correlation knot
Really；
3. using the auto-correlation and cross correlation of PN sequences, the time of arrival (toa) in integral multiple sampling period is detected
Difference, detects that Different Ground digital TV transmitter signal is reached fixed using the fractional time delay filter of fraction times time delay detection device
The fraction times reaching time-difference of position receiver；
4. the integral multiple symbol delay time difference is merged with the fraction times symbol delay time difference and obtains signal total time and prolong
Slow difference；
5. time delay difference is scaled distance and the coordinate setting of receiver is obtained by the geometrical relationship of coordinate.
Present system using up-sampling method improve signal sampling rate, pair with it is known constitute frame head PN sequences
Location receiver, the signal received has time delay during propagation, by the way that sampling rate is brought up into one
Fixed frequency, the arrival time difference precision that can be detected out can be necessarily improved on depth, but improve sampling rate simply
Method will greatly increase the complexity of hardware.
It will be not easy the fraction based on PN sequence phases that direct estimation goes out using fraction times filtering wave by prolonging time device to be delayed again conversion
For the linear signal easily obtained.The wave filter can be realized using the FIR filter of fixed coefficient, therefore its complexity is extremely simple
It is single.
When the fraction times time delay estimated is less than 0.5, the mapping of nonlinear fraction times time delay detection result is turned near
Linear result, so that nonlinear test problems to be converted into linear test problems, reduces time delay detection and estimation
Complexity, and improve the precision of location algorithm.
Estimation error and accuracy compensation are adaptively carried out to the result detected by the signal to noise ratio estimated.
The present invention a kind of high-precision locating method based on ground digital television broadcast signal with it is traditional based on ground
The TDOA localization methods of digital television broadcasting are compared, and ensure that the low of the superperformance of integral multiple sub-sample cycle delay and system
Under the characteristic of complexity, decimal sampling cycle delay can be accurately obtained so as to prominent by carrying out detection using FIR filter
The error in a broken sampling period, which is limited, causes the precision of system to be lifted again；Original detection is compensated using half time delay detecting method
Method, can cause the detection of small several times delay becomes linear, simpler accurate；Use the method energy for receiving signal up-sampling
Enough in the case where not changing the precondition of speed of transmission signal, the orientation distance error estimated is exponentially reduced；Use estimation
The method that the signal to noise ratio gone out carries out adaptively correcting to detection error, can be by the detection to environment come in advance to alignment system
Result carry out estimation error and accuracy compensation.
Brief description of the drawings：
Fig. 1 TDOA principle schematics of the present invention.
Fig. 2 present system block diagrams.
Fig. 3 is detected based on related fraction times time delay TDOA.
Fig. 4 fraction times time delay detection filter time domain shock response schematic diagrames of the present invention.
The frame structure schematic diagram for the digital television ground broadcast signal that Fig. 5 present invention is used.
Embodiment：
The present invention will be further described with specific embodiment below in conjunction with the accompanying drawings.The present embodiment is with the technology of the present invention
It is lower premised on scheme to be implemented, give detailed embodiment and specific operating process, but protection scope of the present invention
It is not limited to following contents.
Fig. 1 is TDOA principle schematics of the present invention, is positioned as shown in figure 1, TDOA positioning is one kind using the time difference
Method.Due to absolute time typically relatively difficult measurement, therefore launched by comparing Different Ground digital TV transmitter
TV signal reaches the time difference of location receiver, with regard to that can make using signal source as focus, and range difference is the hyperbola of major axis, double
The intersection point of curve is exactly the position of receiver.In TDOA algorithms, positioning precision is determined by time difference information, therefore
The present invention is provided high-precision time difference information using ground digital television broadcast signal and draws high-precision range information
Method reaches high-precision positioning result.
In method of the location receiver using up-sampling, the sampling rate for improving signal, to shorten the sampling period；Make
The reaching time-difference in fraction time sampling cycle is estimated from signal is received with fractional time delay filter, this method can be used to accurately
Calculate the distance between terrestrial DTV emitter and location receiver；Using half integer multiple sampling period Delay Estima-tion, carry
The high estimated accuracy when fraction times time delay is less than 0.5；Can also be adaptively inclined to detecting according to the signal to noise ratio of input signal
Difference compensates correction, to improve accuracy of detection.
The frame head of ground digital television broadcast signal is by PN Sequence compositions, and frame originating point information does not change and changed with the data of transmission
Become；The signal received is related to PN sequences progresss of known composition frame head, and auto-correlation using PN sequences with it is mutual
Close characteristic, the relative position of the peak value by detecting relevant peaks, it is possible to estimate different terrestrial DTV emitter institutes
The TV signal launched reaches the reaching time-difference of location receiver.Integer sampling can be detected using the related methods of PN
The signal arrival time difference in cycle, and can detect Different Ground digital TV transmitter signal using fractional time delay filter
The fraction times reaching time-difference of location receiver is reached, so as to obtain more accurate range information.
Because noise can bring negative impact to the estimated accuracy of reaching time-difference, by entering to the signal to noise ratio received
Row estimation, then filter parameter is adaptively adjusted, estimated result can be compensated, with the further precision for improving estimation.
The system architecture of the present invention according to a kind of example of the invention based on ground digital television broadcast as shown in Fig. 2 believed
Number location receiver, including down coversion and sampling apparatus, based on related fraction times time delay TDOA detection means, with data
The receiver location computing device and signal-to-noise ratio (SNR) estimation device of processing function.
Location receiver receives the ground digital television broadcast signal for being directly over channel, in down coversion and sampling apparatus
The ground digital television broadcast signal received is switched into intermediate frequency by radio frequency and sampling obtains discrete signal and sent into and is based on correlation
Fraction times time delay TDOA detection means and signal-to-noise ratio (SNR) estimation device.As shown in figure 3, based on related fraction times time delay TDOA
There is independent module related respectively in detection means and separation TV signal, and detect the time delay with merging TV signal.
According to the testing result, receiver location computing device will use each time difference of TDOA algorithm process and obtain position output,
And the tv signal-noise ratio SNR that is detected according to signal-to-noise ratio (SNR) estimation device adaptively compensates school to detection error
Just, to improve accuracy of detection.
The high-precision locating method that a kind of high-accuracy position system based on ground digital television broadcast signal is carried out includes
Following steps：
1. ground digital television broadcast signal will be received intermediate frequency and sampling acquirement discrete signal is switched to by radio frequency；
2. the PN sequences of discrete signal and locally known composition frame head are subjected to relevant treatment, obtain their cross-correlation knot
Really；
3. using the auto-correlation and cross correlation of PN sequences, the time of arrival (toa) in integral multiple sampling period is detected
Difference, detects that Different Ground digital TV transmitter signal is reached fixed using the fractional time delay filter of fraction times time delay detection device
The fraction times reaching time-difference of position receiver；
4. the integral multiple symbol delay time difference is merged with the fraction times symbol delay time difference and obtains signal total time and prolong
Slow difference；
5. time delay difference is scaled distance and the coordinate setting of receiver is obtained by the geometrical relationship of coordinate.
As shown in figure 5, the frame structure of ground digital television broadcast signal inherently possesses by the frame head of PN Sequence compositions, this
The data that individual frame head is not sent change and changed, and only need to use the changeless frame head sequence in extracting time information
Row, therefore the emitter and signal format of ground digital television broadcast signal need not be changed.
Signal has time delay during propagating in the channel, such time delay can be embodied on signal simultaneously
And can be extracted by auto-correlation.Because the frame head of ground digital television broadcast signal is by default PN Sequence compositions
, thus can in receiver by the PN sequences of the signal received and local known composition frame head while sending into correlator
Carry out relevant treatment, it is possible to obtain their cross correlation results, and due to the autocorrelation performance of PN sequence itself, include PN sequences
The PN sequences for receiving signal and feeding correlator of row can produce correlation peak because of its common PN sequence, because the time prolongs
Delay can be produced to the PN sequences in signal late, then obtained correlation peak can also produce displacement and deformation, and which reflects letter
Number propagation delay.The relevant treatment that receiver passes through the signal sent to the emitter of the different coordinates in office can be obtained by letter
The propagation delay of different receivers number is reached, due to the detection that is difficult of absolute time delay, therefore makes all emitters keep clocks same
Step can be obtained by the propagation time delay difference that unlike signal reaches receiver, and time delay difference is scaled into distance and led to
The geometrical relationship for crossing coordinate can be obtained by the coordinate completion positioning of receiver.Time delay difference is whole by what can directly be read
The signal arrival time difference in several times sampling period and the signal arrival time difference structure in the fraction time sampling cycle that can not directly read
Into.
Because correlated results is not easy directly to be detected, therefore correlated results can be sent into fractional time delay filter,
As shown in figure 4, can be obtained by more accurate range information by the signal after detection after filtering device.
Due to the nonlinear characteristic that the correlation peak of ground digital television broadcast signal has with time delay, line is used
Property fractional time delay filter can not extract accurate small several times delay.Therefore as shown in figure 3, system detection obtain away from
From a half-integer delay estimation module is increased before information, by the time delay of artificial increase half integer multiple, only take
Relatively strong linear small several times delay between the area is as detection interval, by all small several times deferred constraints in linearly stronger part,
More accurate fraction times time delay is can be obtained by, finally the integral multiple detected delay and fraction are delayed are closed again again
And.
Because noise can bring negative impact to the estimated accuracy of reaching time-difference, therefore range information is obtained in system
Afterwards, it need to be estimated by the signal to noise ratio (SNR) of the signal to receiving, wave filter is adaptively adjusted further according to signal to noise ratio
Output gain, to be compensated to estimated result, and further improves the precision of estimation.
Claims (2)
1. a kind of high-accuracy position system based on ground digital television broadcast signal, it is characterised in that including：Down coversion and adopt
Sampling device (1), the fraction times time delay TDOA detection means (2) based on correlation, the receiver location meter with data processing function
Calculate device (3) and signal-to-noise ratio (SNR) estimation device (4)；
The ground digital television broadcast signal received is switched to intermediate frequency by radio frequency and adopted by described down coversion and sampling apparatus (1)
Sample is obtained after discrete signal, is transferred to the described fraction times time delay TDOA detection means (2) and signal-to-noise ratio (SNR) estimation based on correlation
Device (4)；
The PN of the described signal and known composition frame head that are received based on related fraction times time delay TDOA detection means (2)
Sequence carries out cross-correlation, and the delay of detection integral multiple is delayed again with fraction respectively, and fraction is delayed again calibrate after by two
Part delay merges, and will obtain time delay difference and is transferred to receiver location computing device (3)；
Described signal-to-noise ratio (SNR) estimation device (4), by estimating the signal to noise ratio received, is adaptively adjusted wave filter ginseng
Number, the offset that calculating is obtained is transferred to receiver location computing device (3)；
Described receiver location computing device (3) using each time difference of TDOA algorithm process and exports position coordinates, together
When the tv signal-noise ratio SNR that is detected according to signal-to-noise ratio (SNR) estimation device carried out come the deviation adaptively to time delay difference
Compensation correction, improves accuracy of detection；
Described is included based on related fraction times time delay TDOA detection means (2)：Correlator (21), integral multiple time delay detection device
(22), fraction times time delay detection device (23), half integer multiple delay estimator (24) and TDOA time delays combiner (25)；
Described correlator (21), the PN sequences of the ground digital television broadcast signal received and known composition frame head are entered
Row is related；
Described integral multiple time delay detection device (22), Detection and Extraction integral multiple time delay is carried out to correlated results；
Described fraction times time delay detection device (23), carries out Detection and Extraction fraction times time delay, and will be based on PN sequences to correlated results
The related fraction of row is delayed conversion linear signal again；
Described half integer multiple delay estimator (24), for improving the estimated accuracy when fraction times time delay is less than 0.5 symbol；
Described TDOA time delays combiner (25), integral multiple symbol delay time difference and fraction times symbol delay time difference are carried out
The total time delay difference of joint account signal.
2. the height that a kind of high-accuracy position system based on ground digital television broadcast signal using described in claim 1 is carried out
Precision positioning methods, it is characterised in that this method comprises the following steps：
1. ground digital television broadcast signal will be received intermediate frequency and sampling acquirement discrete signal is switched to by radio frequency；
2. the PN sequences of discrete signal and locally known composition frame head are subjected to relevant treatment, obtain their cross correlation results；
3. using the auto-correlation and cross correlation of PN sequences, the signal arrival time difference in integral multiple sampling period is detected, profit
Detect that Different Ground digital TV transmitter signal reaches positioning and connect with the fractional time delay filter of fraction times time delay detection device
The fraction times reaching time-difference of receipts machine；
4. the integral multiple symbol delay time difference merged to obtain the total time delay of signal poor with the fraction times symbol delay time difference
Value；
5. time delay difference is scaled distance and the coordinate setting of receiver is obtained by the geometrical relationship of coordinate.
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| CN105403858A (en) * | 2015-10-28 | 2016-03-16 | 上海电机学院 | Arrival time difference estimation method |
| CN109819516A (en) * | 2019-03-13 | 2019-05-28 | 北京航空航天大学 | A kind of television broadcasting signal forwarding localization method and device |
| CN110261819B (en) * | 2019-06-19 | 2022-11-04 | 南京航空航天大学 | Multi-unmanned aerial vehicle cooperative positioning method based on time delay compensation |
| CN113702901A (en) * | 2021-09-02 | 2021-11-26 | 南京航空航天大学 | Cross-correlation delay estimation method based on signal correlation enhancement |
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