WO2009132252A1

WO2009132252A1 - Receiving data using a gps receiver

Info

Publication number: WO2009132252A1
Application number: PCT/US2009/041633
Authority: WO
Inventors: David Homer Biggs; Eric James Blanchard; Walter Debus, Jr.; David Andrew Pettit; Mark Edward Sutton; Ronnie Daryl Tanner
Original assignee: Axonn, L.L.C.
Priority date: 2008-04-24
Filing date: 2009-04-24
Publication date: 2009-10-29

Abstract

A method for receiving data using a GPS receiver having the steps of: (a) receiving a data signal transmitted at a non-GPS frequency; (b) converting the data signal to a first intermediate frequency signal that is compatible with the GPS receiver; (c) supplying the first intermediate frequency signal to the GPS receiver; (d) converting the first intermediate frequency signal into a bit stream by the GPS receiver; and (e) processing the bit stream into a message.

Description

RECEIVING DATA USING A GPS RECEIVER

This application claims the benefit of provisional application for patent serial number 61/047,743 filed on April 24, 2008, which is incorporated by reference herein in its entirety. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 illustrates the method of one embodiment of the present invention for receiving data using a GPS receiver.

Fig.2 illustrates the device of one embodiment of the present invention.

Fig. 3 illustrates the device of another embodiment of the present invention.

Fig.4 illustrates the device of a further embodiment of the present invention. Fig. 5 illustrates the method of another embodiment of the present invention for receiving data using a GPS receiver.

Fig.6 illustrates the device of another embodiment of the present invention.

Fig.7 illustrates the method of a further embodiment of the present invention for receiving data using a GPS receiver. Fig.8 illustrates the method of another embodiment of the present invention for receiving data using a GPS receiver.

In the following description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration of specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized, and that structural, logical and programming changes may be made without departing from the spirit and scope of the present invention. DESCRIPTION OF THE INVENTION

The present invention provides methods, apparatuses, systems, and computer program products for receiving data using a GPS receiver. Before the present methods, apparatuses, systems, and computer program products are disclosed and described, it is to be understood that this invention is not limited to specific methods, specific components, or to particular compositions, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. It will be apparent to those skilled in the art that various components and devices may be used to carry out the methods, apparatuses, systems, and computer program products of the present invention, including GPS receivers, general purpose processors, application specific processors, field programmable processors, and other components designed or operated to carry out embodiments of the present invention. While embodiments of the present invention may be described and claimed in a particular statutory class, such as the apparatus statutory class, this is for convenience only and one of skill in the art will understand that each embodiment of the present invention can be claimed in any statutory class, including systems, apparatuses, methods, and computer program products. Unless otherwise expressly stated, it is in no way intended that any method or embodiment set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method, system, computer program product, or apparatus claim does not specifically state in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including matters of logic with respect to arrangement of steps or operational flow, plain meaning derived from grammatical organization or punctuation, or the number or type of embodiments described in the specification.

As used in the specification and the appended claims, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "an encoder" includes mixtures of encoders, reference to "an encoder" includes mixtures of two or more such encoders, and the like.

One embodiment of the present invention provides a method for receiving data using a GPS receiver, and is illustrated in Fig. 1. First, a data signal transmitted at a non-GPS frequency is received 101. Then, the data signal is converted 102 to a first intermediate frequency signal that is compatible with the GPS receiver. The first intermediate frequency signal is then supplied 103 to the GPS receiver. Fourth, the first intermediate frequency signal is converted 104 into a bit stream by the GPS receiver. Finally, the bit stream is processed 105 into a message.

There are numerous embodiments that extend the method of Fig. 1 and that are also independently useable with any other embodiment of the present invention. In one such embodiment, the GPS receiver receives a GPS signal from a GPS satellite. The frequency of the data signal can be different from the frequency of an intermediate or internal frequency signal in any embodiment. In various embodiments, the data signal transmitted at a non-GPS frequency is spread with a PN code, such as a GPS PN code, and is modulated at a GPS chip rate as understood by one of skill in the art. Further, the PN code for the data signal transmitted at a non-GPS frequency can be selected from a plurality of GPS PN codes in any embodiment. The plurality of PN codes can be stored in a modified GPS almanac that associates the PN code with a device that transmits data signals at one or more non-GPS frequencies in further embodiments. The GPS almanac can be stored in a memory coupled to the GPS receiver in any embodiment of the present invention. The data signal can comprise at least one or more of a preamble, a device address, and a data unit in any embodiment. The preamble, device address, and data unit can be transmitted or retransmitted one or more times and they can be transmitted in any order in any embodiment of the present invention. The GPS receiver of any embodiment of the present invention can comprise any suitable combination of hardware and software, including or incorporating conventional GPS receivers as well as one or more general purpose, application specific, or field programmable processors programmed to perform embodiments of the present invention.

The bit stream can be processed into a message by the GPS receiver, or it can be processed into a message by a processor that is coupled to the GPS receiver in any embodiment of the present invention. The processor of any embodiment can include the ARM7 series processor, but any suitable processor can be used in embodiments of the present invention. The software executed by a GPS receiver or a processor for processing the bit stream can be stored in a separate memory device such as in a dedicated ROM or flash memory device, or the software can be stored in an pre-existing memory device that is coupled to the GPS receiver.

In another embodiment that can extend the embodiment shown in Fig. 1 , converting the first intermediate frequency signal into a bit stream by the GPS receiver can comprise converting by the GPS receiver the first intermediate frequency signal into a second intermediate frequency signal, and converting the second intermediate frequency signal into a bit stream by the GPS receiver. Processing the bit stream into a message can comprise processing the bit stream into one or more frames in any embodiment of the present invention. A frame can comprise one or more preamble(s), device address(s), or data unit(s). As understood by one of skill in the art, a preamble in any embodiment can be a set of bits that enables a wireless receiver to detect a signal and to synchronize with a wireless transmitter. The device address of any embodiment can comprise a set of bits that indicate or are associated with one or more GPS receivers. The data unit of any embodiment can comprise any type of information, including binary and text data. The preamble, device address, and data units of a frame can be arranged in a frame in any order, and a specific preamble, device address, or data unit can be repeated within a frame or repeated in subsequent frames. Additional information can also be included within a preamble, device address, data unit, or frame, such as checksum or other data.

In further embodiments, the data signal transmitted at a non-GPS frequency can be transmitted from a space-based transmitter, from a mobile terrestrial source, or from a stationary terrestrial source. The non-GPS frequency of any embodiment can be between 2484.39 MHz and 2499.15 MHz in any embodiment. An intermediate frequency signal can be centered substantially around 1575.42 MHz, also known as LI frequency, although any suitable frequency can be used. Embodiments of the present invention can further comprise switching a GPS signal into the GPS receiver to obtain GPS data.

The embodiments of the present invention can further comprise selecting one of the data signal transmitted at a non-GPS frequency or a GPS signal to supply to the GPS receiver according to a schedule. The schedule can be based on at least one of a random or a pseudo-random number. The schedule can be determined using a device identifier that is associated with the GPS receiver. The device identifier can be an electronic serial number, and the schedule can be determined using at least some of the bits, such as the last four bits, of the electronic serial number. The schedule can indicate a time slot from a plurality of time slots that are used to send data to one or more GPS receivers at non-

GPS frequencies.

The non-GPS frequency signal in any embodiment can comprises a signal that does not require a handshake, such as a simplex data signal. Simplex communication is a form of one-way communication that provides for only a transmit or receive path between two network components, and is described for example in U.S. Patent Nos.4,977,577 and 7,099,770, and U.S. Patent Publication

No.20080018496, which are owned by the assignee of the present application and which are each herein incorporated by reference in their entirety for all useful purposes. A simplex data signal can be received, for example, from a satellite such as a Globalstar low-earth-orbit satellite, or from a terrestrial source. The GPS receiver can be portable, and it can be battery or line powered in embodiments of the present invention. The data in a data signal of any embodiment can include any type of non-GPS data, including text data such as messages and binary data such as images.

The method of any embodiment of the present invention, such as the methods described in Figs. 1 , 5, 7, 8 and any related embodiment(s) can comprise a computer-readable medium encoded with computer-readable instructions for performing the disclosed method(s) or embodiments). For example, one embodiment of the present invention provides a computer-readable medium encoded with computer-readable instructions for receiving data using a GPS receiver. Computer readable media or medium includes any tangible media that can be accessed by a computer. By way of example, computer readable mediums include CD-ROM, digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other such tangible media.

Returning to the current embodiment, first, a data signal transmitted at a non-GPS frequency is received. Then, the data signal is converted to a first intermediate frequency signal that is compatible with the GPS receiver. The first intermediate frequency signal is then supplied to the GPS receiver. Fourth, the first intermediate frequency signal is converted into a bit stream by the GPS receiver. Finally, the bit stream is processed into a message.

The method of any embodiment of the present invention, such as the methods described in Figs. 1 , 5, 7, 8 and any related embodiment(s), can be carried out by or comprise a processor programmed to perform the disclosed method(s) or embodiments). For example, one embodiment of the present invention provides a processor programmed to receiving data using a GPS receiver. First, a data signal transmitted at a non-GPS frequency is received. Then, the data signal is converted to a first intermediate frequency signal that is compatible with the GPS receiver. The first intermediate frequency signal is then supplied to the GPS receiver. Fourth, the first intermediate frequency signal is converted into a bit stream by the GPS receiver. Finally, the bit stream is processed into a message. Another embodiment of the present invention provides a device for receiving data using a GPS receiver. Fig. 2 shows the embodiment of one such device. As shown in Fig.2, the device, in one embodiment, includes an antenna 201 that receives a data signal transmitted at a non-GPS frequency and a first converter 202 that converts the data signal into a first intermediate frequency signal compatible with the GPS receiver 203. The GPS receiver 203 converts the first intermediate frequency signal into a bit stream. The GPS receiver 203 can then convert the bit stream into a message. A processor (not shown) coupled to the GPS receiver 203 can also be used to convert the bit stream into a message in any embodiment. There are numerous embodiments that extend the device of Fig. 2 and that are also independently useable with any other embodiment of the present invention. For example, the device shown in Fig. 2 can further comprise a second converter that converts the first intermediate frequency signal into a second intermediate frequency signal and then supplies the second intermediate frequency signal to the GPS receiver for conversion to the bit stream. A converter in any embodiment can comprise a coupling of a bandpass filter, a mixer, and an image rejection filter as understood by one of ordinary skill in the art.

In any embodiment, the device can further comprise a switch that switches a GPS signal into the GPS receiver to obtain GPS data.

Fig. 3 shows another embodiment of a device for receiving data using a GPS receiver. As shown in Fig. 3, the device, in one embodiment, includes an antenna 301 that receives a data signal transmitted at a non-GPS frequency and a first converter 302 that converts the data signal into a first intermediate frequency signal compatible with the GPS receiver 303. The GPS receiver 303 converts the first intermediate frequency signal into a bit stream. A processor 304 coupled to the GPS receiver 303 can then convert the bit stream into a message in any embodiment.

The device of another embodiment for receiving data using a GPS receiver is shown in Fig.4. As shown in Fig.4, the device, in one embodiment, includes a first antenna 401 that receives a data signal transmitted at a non-GPS frequency and a first converter 402 that converts the data signal into a first intermediate frequency signal compatible with the GPS receiver 404. The GPS receiver 404 can convert the first intermediate frequency signal into a bit stream. The GPS receiver 404 can then convert the bit stream into a message containing data In the alternative, a processor (not shown) coupled to the GPS receiver 404 can process the bit stream into a message. A switch 403 couples either the first antenna 401 or the second antenna 405 to the GPS receiver 404. The second antenna 405 can, for example, receive a GPS signal. Accordingly, the GPS receiver 404 can receive and process both GPS and data signals.

The first antenna 401 and the second antenna 405 can comprise the same physical antenna or separate physical antennas in any embodiment.

A further embodiment of the present invention provides a method for receiving data using a GPS receiver, and is shown in Fig.5. First, a plurality of data signals transmitted at one or more non-

GPS frequencies is received 501. Each of the plurality of data signals transmitted at one or more non- GPS frequencies are then converted 502 to a plurality of intermediate frequency signals that are compatible with the GPS receiver. The plurality of intermediate frequency signals are then 503 supplied to a switch. The switch then selects a selected intermediate frequency signal from the plurality of intermediate frequency signals to supply 504 to the GPS receiver. The selected intermediate frequency signal is then converted 505 into a bit stream by the GPS receiver. Finally, the bit stream is processed 506 into a message.

There are numerous embodiments that extend the method of Fig.5 and that are also independently useable with any other embodiment of the present invention. For example, in one embodiment, the method further comprises supplying a GPS signal to the switch, supplying by the switch the GPS signal to the GPS receiver, and processing the GPS signal by the GPS receiver.

In another embodiment, converting the first intermediate frequency signal into a bit stream by the GPS receiver comprises converting by the GPS receiver the first intermediate frequency signal into a second intermediate frequency signal, and converting the second intermediate frequency signal into a bit stream by the GPS receiver.

The methods described with regard to Fig. 5 and any related embodiments) can comprise a computer-readable medium encoded with computer-readable instructions for performing the disclosed method(s) or embodiments). For example, one embodiment provides a computer-readable medium encoded with computer-readable instructions for receiving data using a GPS receiver. First, a plurality of data signals transmitted at one or more non-GPS frequencies is received. Each of the plurality of data signals transmitted at one or more non-GPS frequencies are then converted to a plurality of intermediate frequency signals that are compatible with the GPS receiver. The plurality of intermediate frequency signals are then supplied to a switch. The switch then selects a selected intermediate frequency signal from the plurality of intermediate frequency signals to supply to the GPS receiver. The selected intermediate frequency signal is then converted into a bit stream by the GPS receiver. Finally, the bit stream is processed into a message.

Similarly, the methods described with regard to Fig. 5 and any related embodiment(s) can comprise a processor programmed to perform the disclosed method(s) or embodiment(s). For example, one embodiment of the present invention provides a processor programmed to receiving data using a GPS receiver. First, the processor is programmed to receive a plurality of data signals transmitted at one or more non-GPS frequencies. Each of the plurality of data signals transmitted at one or more non-GPS frequencies are then converted to a plurality of intermediate frequency signals that are compatible with the GPS receiver. The plurality of intermediate frequency signals are then supplied to a switch. The switch then selects a selected intermediate frequency signal from the plurality of intermediate frequency signals to supply to the GPS receiver. The selected intermediate frequency signal is then converted into a bit stream by the GPS receiver. Finally, the bit stream is processed into a message. The device of a further embodiment for receiving data using a GPS receiver is shown in Fig.

6. As shown in Fig. 6, a plurality of antennas 601 -602 can receive a plurality of data signals transmitted at one or more non-GPS frequencies. A third antenna 603 receives a GPS signal. A plurality of converters 604-605 convert the plurality of data signals into a plurality of intermediate frequency signals that are compatible with the GPS receiver 607. A switch 606 selects one of the plurality of intermediate frequency signals or the GPS signal and provides the selected signal to the

GPS receiver 607. The GPS receiver 607 converts the selected signal into a bit stream. Accordingly, the GPS receiver 607 can receive and process both GPS and data signals.

In one embodiment of the present invention, such as in an embodiment extending the device of Fig. 6, the GPS receiver 607 can convert the bit stream into a message. In the alternative, a processor coupled to the GPS receiver 607 can convert the bit stream into a message.

In other embodiments, a third converter receives the selected signal from the switch 606 and converts the selected signal into an internal frequency signal. The GPS receiver 607 or a processor can then convert the bit stream into a message. One or more of the first antenna 601 , the second antenna 602, and the third antenna 603 can comprise the same physical antenna or separate physical antennas in any embodiment.

A further embodiment of the present invention provides a method for receiving data using a GPS receiver, and is shown in Fig, 7. First, one of a data signal transmitted at a non-GPS frequency or a GPS signal is selected 701 to supply to the GPS receiver according to a schedule.

If the data signal transmitted at a non-GPS frequency is selected 702A according to the schedule, one or more steps can be performed. First, for example, the data signal transmitted at a non-GPS frequency is received 703 using a first antenna that is coupled to the GPS receiver, and is then converted 704 into a first intermediate frequency signal that is compatible with the GPS receiver. The GPS receiver then converts 705 the first intermediate frequency signal into a second intermediate frequency signal. The second intermediate frequency signal is then converted 706 into a bit stream. Finally, the bit stream is processed 707 into a message.

If the GPS signal is selected 702B according to the schedule, one or more steps can be performed. First, for example, the GPS signal is received 708 using a second antenna that is coupled to the GPS receiver, and then the GPS signal is supplied 709 to the GPS receiver.

There are numerous embodiments that extend the method of Fig. 7 and that are also independently useable with any other embodiment of the present invention. For example, in one embodiment, processing the bit stream into a message can comprise processing the bit stream into a message by the GPS receiver. In the alternative, processing the bit stream into a message can comprise comprises processing the bit stream into a message by a processor.

The methods described with regard to Fig.7 and any related embodiment(s) can comprise a computer-readable medium encoded with computer-readable instructions for performing the disclosed method(s) or embodiment(s). For example, one embodiment provides a computer-readable medium encoded with computer-readable instructions for receiving data using a GPS receiver. First, one of a data signal transmitted at a non-GPS frequency or a GPS signal is selected to supply to the GPS receiver according to a schedule. If the data signal transmitted at a non-GPS frequency is selected according to the schedule, one or more steps can be performed. First, for example, the data signal transmitted at a non-GPS frequency is received using a first antenna that is coupled to the GPS receiver, and is then converted into a first intermediate frequency signal that is compatible with the GPS receiver. The GPS receiver then converts the first intermediate frequency signal into a second intermediate frequency signal. The second intermediate frequency signal is then converted into a bit stream. Finally, the bit stream is processed into a message. If the GPS signal is selected according to the schedule, one or more steps can be performed. First, for example, the GPS signal is received using a second antenna that is coupled to the GPS receiver, and then the GPS signal is supplied to the GPS receiver.

Similarly, the methods described with regard to Fig. 7 and any related embodiments) can comprise a processor programmed to perform the disclosed method(s) or embodiments). For example, one embodiment of the present invention provides a processor programmed to receiving data using a GPS receiver. First, one of a data signal transmitted at a non-GPS frequency or a GPS signal is selected to supply to the GPS receiver according to a schedule. If the data signal transmitted at a non-GPS frequency is selected according to the schedule, one or more steps can be performed. First, for example, the data signal transmitted at a non-GPS frequency is received using a first antenna that is coupled to the GPS receiver, and is then converted into a first intermediate frequency signal that is compatible with the GPS receiver. The GPS receiver then converts the first intermediate frequency signal into a second intermediate frequency signal. The second intermediate frequency signal is then converted into a bit stream. Finally, the bit stream is processed into a message. If the GPS signal is selected according to the schedule, one or more steps can be performed. First, for example, the GPS signal is received using a second antenna that is coupled to the GPS receiver, and then the GPS signal is supplied to the GPS receiver.

Another embodiment of the present invention provides a method for receiving data using a GPS receiver, and is shown in Fig. 8. First a data signal transmitted at a non-GPS frequency is received 801. Second, the data signal is converted 802 to a first intermediate frequency signal that is compatible with the GPS receiver, and the first intermediate frequency signal is supplied 803 to the

GPS receiver. Fourth, the GPS receiver converts 804 the first intermediate frequency signal into a first bit stream using a first PN code and into a second bit stream using a second PN code. Finally, the first bit stream is processed 805 into a first message while the second bit stream is processed into a second message. There are numerous embodiments that extend the method of Fig. 8 and that are also independently useable with any other embodiment of the present invention. For example, processing the first and second bit streams into a first and a second message can be performed by the GPS receiver or by a processor coupled to the GPS receiver.

The methods described with regard to Fig.8 and any related embodiment(s) can comprise a computer-readable medium encoded with computer-readable instructions for performing the disclosed method(s) or embodiments). For example, one embodiment provides a computer-readable medium encoded with computer-readable instructions for receiving data using a GPS receiver. First a data signal transmitted at a non-GPS frequency is received. Second, the data signal is converted to a first intermediate frequency signal that is compatible with the GPS receiver, and the first intermediate frequency signal is supplied to the GPS receiver. Fourth, the GPS receiver converts the first intermediate frequency signal into a first bit stream using a first PN code and into a second bit stream using a second PN code. Finally, the first bit stream is processed into a first message while the second bit stream is processed into a second message.

Similarly, the methods described with regard to Fig. 8 and any related embodiment(s) can comprise a processor programmed to perform the disclosed method(s) or embodiment(s). For example, one embodiment of the present invention provides a processor programmed to receiving data using a GPS receiver. First a data signal transmitted at a non-GPS frequency is received. Second, the data signal is converted to a first intermediate frequency signal that is compatible with the GPS receiver, and the first intermediate frequency signal is supplied to the GPS receiver. Fourth, the GPS receiver converts the first intermediate frequency signal into a first bit stream using a first PN code and into a second bit stream using a second PN code. Finally, the first bit stream is processed into a first message while the second bit stream is processed into a second message. While the present invention has been described in detail in connection with various embodiments, it should be understood that the present invention is not limited to the above-disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alternations, substitutions, or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention.

Claims

CLAIMSWe claim

1. A method for receiving data using a GPS receiver, comprising: a receiving a data signal transmitted at a non-GPS frequency; b. converting the data signal to a first intermediate frequency signal that is compatible with the GPS receiver; c. supplying the first intermediate frequency signal to the GPS receiver; d. converting the first intermediate frequency signal into a bit stream by the GPS receiver; and e. processing the bit stream into a message.

2. The method of claim 1 , wherein the data signal transmitted at a non-GPS frequency is spread with a PN code and is modulated at a GPS chip rate.

3. The method of claims 1 and 2, wherein the data signal comprises at least a preamble, a device address, and a data unit.

4. The method of claims 1 -3, wherein processing the bit stream into a message comprises processing the bit stream into a message by the GPS receiver

5. The method of claims 1 -3, wherein processing the bit stream into a message comprises processing the bit stream into a message by a processor.

6. The method of claims 1 -5, wherein converting the first intermediate frequency signal into a bit stream by the GPS receiver comprises: a. converting by the GPS receiver the first intermediate frequency signal into a second intermediate frequency signal; and b. converting the second intermediate frequency signal into a bit stream by the GPS receiver.

7. The method of claims 1 -3 and 5-6, wherein processing the bit stream into a message comprises processing the bit stream into a frame.

8. The method of claim 7, wherein the frame comprises a preamble.

9. The method of claims 6 and 7, wherein the frame comprises a device address.

10. The method of claims 7-9, wherein the frame comprises a data unit.

11. The method of claims 1 -10, further comprising transmitting the data signal transmitted at a non-

GPS frequency from a space-based transmitter.

12 The method of claims 1-10, further comprising transmitting the data signal transmitted at a non-GPS frequency from a mobile terrestrial source.

13. The method of claims 1-10, further comprising transmitting the data signal transmitted at a non-GPS frequency from a stationary terrestrial source.

14. The method of claims 1-13, wherein the non-GPS frequency is between 2484.39 MHz and 2499.15 MHz.

15. The method of claims 1-14, wherein the first intermediate frequency signal is centered substantially around 1575.42 MHz.

16. The method of claims 1-15, further comprising switching a GPS signal into the GPS receiver to obtain GPS data.

17. The method of claims 1 -16, further comprising selecting one of the data signal transmitted at a non-GPS frequency or a GPS signal to supply to the GPS receiver according to a schedule.

18. The method of claim 17, wherein the schedule is based on at least one of a random or a pseudo-random number.

19. The method of claim 17, wherein the schedule is determined using a device identifier that is associated with the GPS receiver.

20. The method of claim 19, wherein the device identifier is an electronic serial number.

21. The method of claim 20, wherein the schedule is determined using at least some of the bits from the electronic serial number.

22. The method of claims 1-21 , wherein the non-GPS frequency signal comprises a simplex data signal.

23. The method of claim 22, wherein the simplex data signal is received from a Globalstar low- earth-orbit satellite.

24. The method of claims 1-23, wherein the GPS receiver is portable.

25. The method of claims 1 -24, wherein the GPS receiver is battery powered.

26. The method of claim 2, further comprising selecting the PN code for the data signal transmitted at a non-GPS frequency from a plurality of GPS PN codes.

27. The method of claim 26, wherein the plurality of PN codes is stored in a modified GPS almanac that associates the PN code with a device that transmits data signals at one or more non-GPS frequencies.

28. A system comprising a processor programmed to perform the method of claims 1 -27.

29. A computer-readable medium encoded with computer-readable instructions for performing the method of claims 1-27.

30. A device for receiving data using a GPS receiver, comprising: a an antenna that receives a data signal transmitted at a non-GPS frequency; b. a first converter that converts the data signal into a first intermediate frequency signal compatible with the GPS receiver; c. the GPS receiver for converting the first intermediate frequency signal into a bit stream; and d a processor that converts the bit stream into a message.

31. The device of claim 30 further comprising a second converter that converts the first intermediate frequency signal into a second intermediate frequency and then supplies the second intermediate frequency signal to the GPS receiver for conversion to the bit stream.

32. The device of claims 30-31 , wherein at least one of the first converter or the second converter comprises a coupling of a bandpass filter, a mixer, and an image rejection filter.

33. The device of claims 30-32, wherein the data signal transmitted at a non-GPS frequency is spread with a PN code and is modulated at a GPS chip rate.

34. The device of claims 30-33, wherein the data signal comprises at least a preamble, a device address, and a data unit.

35. The device of claims 30-33, wherein the bit stream is processed into a message by the GPS receiver.

36. The device of claims 30-33, wherein the bit stream is processed into a message by a processor.

37. The device of claims 30-36, wherein the GPS receiver converts the first intermediate frequency signal into a second intermediate frequency signal, and wherein the second intermediate frequency signal is converted into a bit stream by one of the GPS receiver or a processor coupled to the GPS receiver.

38. The device of claims 30-33 and 35-37, wherein the bit stream is processed into a frame.

39. The device of claim 38, wherein the frame comprises a preamble.

40. The device of claims 38 and 39, wherein the frame comprises a device address.

41. The device of claims 38-40, wherein the frame comprises a data unit.

42. The device of claims 3041 , wherein the data signal is transmitted at a non-GPS frequency from a space-based transmitter.

43. The device of claims 30-41, wherein the data signal is transmitted at a non-GPS frequency from a mobile terrestrial source.

44. The device of claims 3041 , wherein the data signal transmitted at a non-GPS frequency from a stationary terrestrial source.

45. The device of claims 3044, wherein the non-GPS frequency is between 2484.39 MHz and

2499.15 MHz.

46. The device of claims 30-45, wherein the first intermediate frequency signal is centered substantially around 1575.42 MHz.

47. The device of claims 30-46, further comprising a switch that switches a GPS signal into the GPS receiver to obtain GPS data.

48. The device of claims 30-47, wherein one of the data signal transmitted at a non-GPS frequency or a GPS signal is selected to supply to the GPS receiver according to a schedule.

49. The device of claim 48, wherein the schedule is based on at least one of a random or a pseudo-random number.

50. The device of claim 48, wherein the schedule is determined using a device identifier that is associated with the GPS receiver.

51. The device of claim 50, wherein the device identifier is an electronic serial number.

52. The device of claim 51 , wherein the schedule is determined using at least some of the bits from the electronic serial number.

53. The device of claims 30-52, wherein the non-GPS frequency signal comprises a simplex data signal.

54. The device of claim 53, wherein the simplex data signal is received from a Globalstar low- earth-orbit satellite.

55. The device of claim 33, wherein the PN code for the data signal transmitted at a non-GPS frequency is selected from a plurality of GPS PN codes.

56. The device of claim 55, wherein the plurality of PN codes is stored in a modified GPS almanac that associates the PN code with a device that transmits data signals at one or more non-GPS frequencies.

57. The device of claims 30-56, wherein the GPS receiver is portable.

58. The device of claims 30-56, wherein the GPS receiver is battery powered.

59. A method for receiving data using a GPS receiver, comprising: a receiving a plurality of data signals transmitted at one or more non-GPS frequencies; b. converting each of the plurality of data signals transmitted at one or more non-GPS frequencies to a plurality of intermediate frequency signals that are compatible with the GPS receiver; c. supplying the plurality of intermediate frequency signals to a switch; d supplying by the switch a selected intermediate frequency signal from the plurality of intermediate frequency signals to the GPS receiver; e. converting the selected intermediate frequency signal into a bit stream by the GPS receiver; and

5 f. processing the bit stream into a message.

60. The method of claim 59, further comprising: a supplying a GPS signal to the switch; b. supplying by the switch the GPS signal to the GPS receiver; and c. processing the GPS signal by the GPS receiver.

10 61. The method of claims 59-60, wherein the data signal transmitted at a non-GPS frequency is spread with a PN code and is modulated at a GPS chip rate.

62. The method of claims 59-61 , wherein the data signal comprises at least a preamble, a device address, and a data unit.

63. The method of claims 59-62, wherein processing the bit stream into a message comprises ] 5 processing the bit stream into a message by the GPS receiver

64. The method of claims 59-62, wherein processing the bit stream into a message comprises processing the bit stream into a message by a processor.

65. The method of claims 59-64, wherein converting the first intermediate frequency signal into a bit stream by the GPS receiver comprises: 0 d. converting by the GPS receiver the first intermediate frequency signal into a second intermediate frequency signal; and e. converting the second intermediate frequency signal into a bit stream by the GPS receiver.

66. The method of claims 59-61 and 63-65, wherein processing the bit stream into a message 25 comprises processing the bit stream into a frame.

67. The method of claim 66, wherein the frame comprises a preamble.

68. The method of claims 66 and 67, wherein the frame comprises a device address.

69. The method of claims 66-68, wherein the frame comprises a data unit.

70. The method of claims 59-69, further comprising transmitting the data signal transmitted at a 30 non-GPS frequency from a space-based transmitter.

71. The method of claims 59-70, further comprising transmitting the data signal transmitted at a non-GPS frequency from a mobile terrestrial source.

72 The method of claims 59-71 , further comprising transmitting the data signal transmitted at a non-GPS frequency from a stationary terrestrial source.

73. The method of claims 59-72, wherein the non-GPS frequency is between 2484.39 MHz and 2499.15 MHz.

74. The method of claims 59-73, wherein the first intermediate frequency signal is centered substantially around 1575.42 MHz.

75. The method of claims 59-74, further comprising switching a GPS signal into the GPS receiver to obtain GPS data.

76. The method of claims 59-75, further comprising selecting one of the data signal transmitted at a non-GPS frequency or a GPS signal to supply to the GPS receiver according to a schedule.

77. The method of claim 76, wherein the schedule is based on at least one of a random or a pseudo-random number.

78. The method of claim 76, wherein the schedule is determined using a device identifier that is associated with the GPS receiver.

79. The method of claim 78, wherein the device identifier is an electronic serial number.

80. The method of claim 79, wherein the schedule is determined using at least some of the bits from the electronic serial number.

81. The method of claims 59-80, wherein the non-GPS frequency signal comprises a simplex data signal.

82. The method of claim 81 , wherein the simplex data signal is received from a Globalstar low- earth-orbit satellite.

83. The method of claims 59-82, wherein the GPS receiver is portable.

84. The method of claims 59-83, wherein the GPS receiver is battery powered.

85. The method of claim 61 , further comprising selecting the PN code for the data signal transmitted at a non-GPS frequency from a plurality of GPS PN codes.

86. The method of claim 85, wherein the plurality of PN codes is stored in a modified GPS almanac that associates the PN code with a device that transmits data signals at one or more non-GPS frequencies.

87. A system comprising a processor programmed to perform the method of claims 59-86.

88. A computer-readable medium encoded with computer-readable instructions for performing the method of claims 59-86.

89. A device for receiving data using a GPS receiver, comprising: a a plurality of antennas that receive a plurality of data signals transmitted at one or more non-GPS frequencies; b. an antenna that receives a GPS signal; c. a plurality of converters that convert the plurality of data signals into a plurality of intermediate frequency signals that are compatible with the GPS receiver; d a switch that selects one of the plurality of intermediate frequency signals or the GPS signal and provides the selected signal to the GPS receiver, wherein the GPS receiver converts the selected signal into a bit stream; and e. a processor that converts the bit stream into a message.

90. The device of claims 89, further comprising a second converter that converts the selected signal into a second intermediate frequency and then supplies the second intermediate frequency signal to the GPS receiver for conversion to the bit stream.

91. The device of claims 89-90, wherein at least one of the first converter or the second converter comprises a coupling of a bandpass filter, a mixer, and an image rejection filter.

92. The device of claims 89-91, wherein the data signal transmitted at a non-GPS frequency is spread with a PN code and is modulated at a GPS chip rate.

93. The device of claims 89-92, wherein the data signal comprises at least a preamble, a device address, and a data unit.

94. The device of claims 89-92, wherein the bit stream is processed into a message by the GPS receiver

95. The device of claims 89-92, wherein the bit stream is processed into a message by a processor.

96. The device of claims 89-95, wherein the GPS receiver converts the first intermediate frequency signal into a second intermediate frequency signal, and wherein the second intermediate frequency signal is converted into a bit stream by one of the GPS receiver or a processor coupled to the GPS receiver.

97. The device of claims 89-92 and 94-96, wherein the bit stream is processed into a frame .

98. The device of claim 97, wherein the frame comprises a preamble.

99. The device of claims 97 and 98, wherein the frame comprises a device address.

100. The device of claims 97-99, wherein the frame comprises a data unit.

101. The device of claims 89-100, wherein the data signal is transmitted at a non-GPS frequency from a space-based transmitter.

102. The device of claims 89-100, wherein the data signal is transmitted at a non-GPS frequency from a mobile terrestrial source.

103. The device of claims 89- 100, wherein the data signal transmitted at a non-GPS frequency from a stationary terrestrial source.

104. The device of claims 89-103, wherein the non-GPS frequency is between 2484.39 MHz and 2499.15 MHz.

105. The device of claims 89- 104, wherein the first intermediate frequency signal is centered substantially around 1575.42 MHz.

106. The device of claims 89-105, further comprising a switch that switches a GPS signal into the GPS receiver to obtain GPS data.

107. The device of claims 89- 106, wherein one of the data signal transmitted at a non-GPS frequency or a GPS signal is selected to supply to the GPS receiver according to a schedule.

108. The device of claim 107, wherein the schedule is based on at least one of a random or a pseudo-random number.

109. The device of claim 107, wherein the schedule is determined using a device identifier that is associated with the GPS receiver.

110. The device of claim 109, wherein the device identifier is an electronic serial number.

111. The device of claim 110, wherein the schedule is determined using at least some of the bits from the electronic serial number.

112. The device of claims 89-111 , wherein the non-GPS frequency signal comprises a simplex data signal.

113. The device of claim 112, wherein the simplex data signal is received from a Globalstar low- earth-orbit satellite.

114. The device of claims 89-113, wherein the GPS receiver is portable.

115. The device of claims 89-114, wherein the GPS receiver is battery powered.

116. The device of claims 89-115, wherein the processor comprises the GPS receiver.

117. The device of claim 92, wherein the PN code for at least one data signal transmitted at a non- GPS frequency is selected from a plurality of GPS PN codes.

118. The device of claim 117, wherein the plurality of PN codes is stored in a modified GPS almanac that associates the PN code with a device that transmits data signals at one or more non-GPS frequencies.

119. A method for receiving data using a GPS receiver, comprising: a selecting one of a data signal transmitted at a non-GPS frequency or a GPS signal to supply to the GPS receiver according to a schedule; b. if the data signal transmitted at a non-GPS frequency is selected according to the schedule, performing: i. receiving the data signal transmitted at a non-GPS frequency using a first antenna that is coupled to the GPS receiver;

5 ii. converting the data signal transmitted at a non-GPS frequency into a first intermediate frequency signal that is compatible with the GPS receiver; iii. converting by the GPS receiver the first intermediate frequency signal into a second intermediate frequency signal; l o iv. converting the second intermediate frequency signal into a bit stream; and v. processing the bit stream into a message; c. else if the GPS signal is selected according to the schedule, performing: i. receiving the GPS signal using a second antenna that is coupled to the GPS receiver; and 15 ii. supplying the GPS signal to the GPS receiver.

120. The method of claim 119, wherein the data signal transmitted at a non-GPS frequency is spread with a PN code and is modulated at a GPS chip rate.

121. The method of claim 119 or 120, wherein the data signal comprises at least a preamble, a device address, and a data unit. 0

122. The method of claim 119 or 120, wherein processing the bit stream into a message comprises processing the bit stream into a message by the GPS receiver.

123. The method of claim 119 or 120, wherein processing the bit stream into a message comprises processing the bit stream into a message by a processor.

124. The method of claim 123, wherein processing the bit stream into a message comprises 25 processing the bit stream into a frame.

125. The method of claim 124, wherein the frame comprises a preamble.

126. The method of claim 125, wherein the frame comprises a device address.

127. The method of claim 126, wherein the frame comprises a data unit.

128. The method of claim 119 or 120, further comprising transmitting the data signal transmitted at 0 a non-GPS frequency from a space-based transmitter.

129. The method of claim 119 or 120, further comprising transmitting the data signal transmitted at a non-GPS frequency from a mobile terrestrial source.

130. The method of claim 119 or 120, further comprising transmitting the data signal transmitted at a non-GPS frequency from a stationary terrestrial source.

131. The method of claim 119 or 120, wherein the non-GPS frequency is between 2484.39 MHz and 2499.15 MHz.

132. The method of claim 119 or 120, wherein the first intermediate frequency signal is centered substantially around 1575.42 MHz.

133. The method of claim 119 or 120, wherein the schedule is based on at least one of a random or a pseudo-random number.

134. The method of claim 119 or 120, wherein the schedule is determined using a device identifier that is associated with the GPS receiver.

135. The method of claim 134, wherein the device identifier is an electronic serial number.

136. The method of claim 135, wherein the schedule is determined using at least some of the bits from the electronic serial number.

137. The method of claim 119 or 120, wherein the non-GPS frequency signal compri ses a simplex data signal.

138. The method of claim 137, wherein the simplex data signal is received from a Globalstar low- earth-orbit satellite.

139. The method of claim 119 or 120, wherein the GPS receiver is portable.

140. The method of claims 119-139, wherein the GPS receiver is battery powered.

141. The method of claim 119 or 120, further comprising processing the GPS signal by the GPS receiver.

142. The method of claim 120, further comprising selecting the PN code for the data signal transmitted at a non-GPS frequency from a plurality of GPS PN codes.

143. The method of claim 142, wherein the plurality of PN codes is stored in a modified GPS almanac that associates the PN code with a device that transmits data signals at one or more non-GPS frequencies.

144. A system comprising a processor programmed to perform the method of claims 119-143.

145. A computer-readable medium encoded with computer-readable instructions for performing the method of claim 119 or 120.

146. A device for receiving data using a GPS receiver, comprising: a a first antenna that receives a first data signal transmitted at a first non-

GPS frequency; b. a second antenna that receives a second data signal transmitted at a second non-GPS frequency; c. a third antenna that receives a GPS signal; d a first converter that converts the first data signal transmitted at a first non-

GPS frequency into a first intermediate frequency signal that is compatible with the GPS receiver; e. a second converter that converts the second data signal transmitted at a second non-GPS frequency into a second intermediate frequency signal that is compatible with the GPS receiver; £ a switch that connects a selected signal comprising one of the GPS signal, the first intermediate frequency signal, or the second intermediate frequency signal to the GPS receiver; and g. a third converter that converts the selected signal into an internal frequency signal, wherein the GPS receiver converts the internal frequency signal into a bit stream that is processed into a message.

147. The device of claim 146, wherein at least one of the first converter or the second converter comprises a coupling of a bandpass filter, a mixer, and an i mage rej ection fi lter.

148. The device of claim 146 or 147, wherein at least one ofthe first data signal or the second data signal is transmitted at a non-GPS frequency is spread with a PN code and is modulated at a GPS chip rate.

149. The device of claim 146 or 147, wherein at least one ofthe data signal or the second data signal comprises at least a preamble, a device address, and a data unit.

150. The device of claim 146 or 147, wherein the bit stream is processed into a message by the GPS receiver.

151. The device of claim 146 or 147, wherein the bit stream is processed into a message by a processor.

152. The device of claim 146 or 147, wherein the bit stream is processed into a frame.

153. The device of claim 152, wherein the frame comprises a preamble.

154. The device of claim 153, wherein the frame comprises a device address.

155. The device of claim 152, wherein the frame comprises a data unit.

156. The device of claim 146 or 147, wherein at least one ofthe first data signal or the second data signal is transmitted at a non-GPS frequency from a space-based transmitter.

157. The device of claim 146 or 147, wherein at least one of the first data signal or the second data signal is transmitted at a non-GPS frequency from a mobile terrestrial source.

158. The device of claim 146 or 147, wherein at least one ofthe first data signal or the second data signal is transmitted at a non-GPS frequency from a stationary terrestrial source.

159. The device of claim 146 or 147, wherein the non-GPS frequency is between 2484.39 MHz and 2499.15 MHz.

160. The device of claim 146 or 147, wherein the first intermediate frequency signal is centered substantially around 1575.42 MHz.

161. The device of claim 146 or 147, wherein one of the data signal transmitted at a non-GPS frequency or a GPS signal is selected to supply to the GPS receiver according to a schedule.

162. The device of claim 161 , wherein the schedule is based on at least one of a random or a pseudo-random number.

163. The device of claim 161, wherein the schedule is determined using a device identifier that is associated with the GPS receiver.

164. The device of claim 163, wherein the device identifier is an electronic serial number.

165. The device of claim 164, wherein the schedule is determined using at least some of the bits from the electronic serial number.

166. The device of claim 146 or 147, wherein the non-GPS frequency signal comprises a simplex data signal.

167. The device of claim 166, wherein the simplex data signal is received from a Globalstar low- earth-orbit satellite.

168 The device of claim 148, wherein the PN code for at least one data signal transmitted at a non- GPS frequency is selected from a plurality of GPS PN codes .

169. The device of claim 168, wherein the plurality of PN codes is stored in a modified GPS almanac that associates the PN code with a device that transmits data signals at one or more non-GPS frequencies.

170. The device of claim 146 or 147, wherein the GPS receiver is portable.

171. The device of claim 146 or 147, wherein the GPS receiver is battery powered.

172 A method for receiving data using a GPS receiver, comprising: a receiving a data signal transmitted at a non-GPS frequency; b. converting the data signal to a first intermediate frequency signal that is compatible with the GPS receiver; c. supplying the first intermediate frequency signal to the GPS receiver; d. converting by the GPS receiver the first intermediate frequency signal into a first bit stream using a first PN code and into a second bit stream using a second PN code; and e. simultaneously processing the first bit stream into a first message and the second bit stream into a second message.

173. The method of claim 172, wherein simultaneously processing the first bit stream into a first message and the second bit stream into a second message comprises simultaneously processing the first bit stream into a first message and the second bit stream into a second message by the GPS receiver.

174. The method of claim 172, wherein simultaneously processing the first bit stream into a first message and the second bit stream into a second message comprises simultaneously processing the first bit stream into a first message and the second bit stream into a second message by a processor.

175. The method of claims 172-174, wherein converting by the GPS receiver the first intermediate frequency signal into a first bit stream using a first PN code and into a second bit stream using a second PN code comprises: a converting by the GPS receiver the first intermediate frequency signal into a second intermediate frequency signal; and b. converting by the GPS receiver the second intermediate frequency signal into a first bit stream using a first PN code and into a second bit stream using a second PN code.

176. The method of claims 172- 175 , wherein simultaneously processing the first bit stream into a first message and the second bit stream into a second message comprises simultaneously processing the first bit stream into a first message comprising a first frame and the second bit stream into a second message comprising a second frame.

177. The method of claim 176, wherein at least one of the first frame or the second frame comprises a preamble.

178. The method of claims 176-177, wherein at least one of the first frame or the second frame comprises a device address.

179. The method of claims 176- 177, wherein at least one of the first frame or the second frame comprises a data unit.

180. The method of claims 172- 179, further comprising transmitting the data signal transmitted at a non-GPS frequency from a space-based transmitter.

181. The method of claims 172-179, further comprising transmitting the data signal transmitted at a non-GPS frequency from a mobile terrestrial source.

182 The method of claims 172- 179, further comprising transmitting the data signal transmitted at a non-GPS frequency from a stationary terrestrial source.

183. The method of claims 172-182, wherein the non-GPS frequency is between 2484.39 MHz and 2499.15 MHz.

184. The method of claims 172-183, wherein the first intermediate frequency signal is centered substantially around 1575.42 MHz.

185. The method of claims 172- 184, further comprising switching a GPS signal into the GPS receiver to obtain GPS data.

186. The method of claims 172- 185, further comprising selecting one of the data signal transmitted at a non-GPS frequency or a GPS signal to supply to the GPS receiver according to a schedule.

187. The method of claim 186, wherein the schedule is based on at least one of a random or a pseudo-random number.

188. The method of claim 186, wherein the schedule is determined using a device identifier that is associated with the GPS receiver.

189. The method of claim 188, wherein the device identifier is an electronic serial number.

190. The method of claim 189, wherein the schedule is determined using at least some of the bits from the electronic serial number.

191. The method of claims 172- 190, wherein the non-GPS frequency signal comprises a simplex data signal.

192. The method of claim 191, wherein the simplex data signal is received from a Globalstar low- earth-orbit satellite.

193. The method of claims 172-192, wherein the GPS receiver is portable.

194. The method of claims 172-193, wherein the GPS receiver is battery powered.

195. The method of claims 172-194, further comprising selecting at least one of the first PN code or the second PN code from a plurality of PN codes.

196. The method of claim 195, wherein the plurality of PN codes are stored in a modified GPS almanac that associates the first PN code and the second PN code with at least a first device that transmits data signals at one or more non-GPS frequencies.

197. The method of claim 172, further comprising selecting at least one of the first PN code or the second PN code from a plurality of PN codes.

198. The method of claim 197, wherein the plurality of PN codes are stored in a modified GPS almanac that associates the first PN code and the second PN code with a device that transmits data signals at one or more non-GPS frequencies.

199. The method of claim 198, wherein the device comprises a low-earth-orbit satellite.

200. The method of claim 199, wherein the low-earth-orbit satellite comprises a Globalstar low- earth-orbit satellite.

201. A system comprising a processor programmed to perform the method of claims 172-200.

202. A computer-readable medium encoded with computer-readable instructions for performing the method of claims 172-200.