System and method for positioning using hybrid spectral compression and cross correlation signal processing

• US 9,455,762 B2
• Filed: 06/30/2015
• Issued: 09/27/2016
• Est. Priority Date: 04/28/2006
• Status: Active Grant

• Current Assignee: TeleCommunication Systems Inc (Comtech Telecommunications Corporation)
• Original Assignee: TeleCommunication Systems Inc (Comtech Telecommunications Corporation)
• Inventors: Mathews, Michael B., MacDoran, Peter F.
• Primary Examiner(s): Vo, Don N
• Application Number:
  US14/788,263
• Publication Number:
  US 20150303989A1
• Time in Patent Office: 455 Days
• Field of Search: 375/144, 375/145, 375/148, 375/149
• US Class Current: 1/1
• CPC Class Codes: G01S 19/11 wherein the cooperating elements are pseudolites or satellite radio beacon positioning system signal repeaters
• CPC Class Codes: G01S 19/23 Testing, monitoring, correcting or calibrating of receiver elements
• CPC Class Codes: G01S 19/256 relating to timing, e.g. time of week, code phase, timing offset
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence
• CPC Class Codes: H04B 1/709 Correlator structure

Abstract

The present invention relates to a system and method for positioning and navigation using hybrid spectral compression and cross correlation signal processing of signals of opportunity, which may include Global Navigation Satellite System (GNSS) as well as other wideband energy emissions in GNSS obstructed environments. Examples of these signals of opportunity include but are not limited to GPS, GLONASS, cellular Code Division Multiple Access (CDMA) communications signals, and 802.11 Wi-Fi. Combining spectral compression with spread spectrum cross correlation enables extraction of code and carrier observables without the need to implement the tracking loops (e.g. Costas tracking loop) commonly used in conventional GNSS receivers. For applications where dynamics and transmission medium may make it difficult to continuously track carrier phase, the hybrid approach of the present invention has significant utility.

Claims

1. A system for providing physical state information comprising:

a plurality of ranging signal transmitters (RSTs) that each emit a spread spectrum radio frequency (RF) emission at a corresponding predetermined spread spectrum chipping frequency within a transmission medium, wherein a given RST is designated as a reference spectral compressor and translator (SCT);

an interceptor that receives the spread spectrum RF emissions emission propagated through the transmission medium from each of the plurality of RSTs;

a spectral compressor configured to process the intercepted spread spectrum RF emissions using spectral compression utilizing a non-linear operation to produce at set of observables for the plurality of RSTs suitable for physical state estimation;

wherein the non-linear operation comprises;

splitting each spread spectrum RF emission into an in-phase component and delayed component;

mixing each of the in-phase and delayed components to recover a corresponding predetermined spread spectrum chipping rate;

wherein a set of reference observables that characterizes a physical state of the reference SCT is received from the reference SCT;

a physical state estimator configured to determine at least one member of the relative physical state between the interceptor and the plurality of RSTs based on the non-linear operations and on the set of reference observables.

2. The system for providing physical state information of claim 1, further comprising:

a reference network processor configured to provide almanac data corrections for the physical state estimator, wherein the at least one member of the relative physical state between the interceptor and the plurality of RSTs is further based on the almanac data corrections.

3. The system for providing physical state information of claim 2, wherein the almanac data corrections comprises an estimated state vector for each of the plurality of RSTs.

4. The system for providing physical state information of claim 2, wherein the reference network processor is further configured to compute a physical state of each of the plurality of RSTs.

5. The system for providing physical state information of claim 4, wherein the almanac data corrections further comprises coefficients for a propagation model that enables the almanac and corrections data to be employed at a future time.

6. The system for providing physical state information of claim 4, wherein the physical state estimator is further configured to estimate a position of each of the plurality of RSTs.

7. The system for providing physical state information of claim 6, wherein the physical state estimator is further configured to estimate a velocity of each of the plurality of RSTs.

8. The system for providing physical state information of claim 1, wherein the at least one member of the relative physical state between the interceptor and each of the plurality of RSTs includes a position of the interceptor.

9. The system for providing physical state information of claim 1, wherein the at least one member of the relative physical state between the interceptor and each of the plurality of RSTs includes a clock for a specific time.

10. The system for providing physical state information of claim 1, wherein the in-phase component of each split spread spectrum RF emission is in-phase with a respective spread spectrum RF emission component and the delayed component is a version of the respective spread spectrum RF emission that is delayed by an interval of about half the corresponding predetermined spread spectrum chipping frequency.

11. A method for providing physical state information comprising:

intercepting a plurality of spread spectrum radio frequency (RF) emissions from a plurality of ranging signal transmitters (RSTs) within a transmission medium, wherein a given RST is designated as a reference compressor and translator (SCT);

processing the plurality of emissions using spectral compression utilizing a non-linear operation to produce a set of observables associated the emitter, wherein the non-linear operation comprises at least two delay and multiply functions;

determining at least one member of a relative physical state between an interceptor and the plurality of RSTs based on the set of observables and on a reference set of observables received from the reference SCT.

12. The method for providing physical state information of claim 11, further comprising:

generating almanac data corrections, wherein the at least one member of the relative physical state between the interceptor and the plurality of RSTs is further based on the almanac data corrections.

13. The method for providing physical state information of claim 12, further comprising computing a physical state of each of the plurality RSTs relative to each other.

14. The method for providing physical state information of claim 13, wherein the physical state includes a position of each of the plurality of RSTs.

15. The method for providing physical state information of claim 14, wherein the physical state further includes a velocity of each of the plurality of RSTs.

16. The method for providing physical state information of claim 12, wherein the almanac data corrections comprises an estimated state vector for each of the plurality of RSTs.

17. The method for providing physical state information of claim 16, wherein the almanac data corrections further comprises coefficients for a propagation model that enables the almanac data corrections to be employed at a future time.

18. The method for providing physical state information of claim 11, wherein the at least one member of the relative physical state between the interceptor and the plurality of RSTs includes a position of the interceptor.

19. The method for providing physical state information of claim 11, wherein the at least one member of the relative physical state between the interceptor and the plurality of RSTs includes a clock for a specific time.

20. The method for providing physical state information of claim 11, wherein the at least two delay and multiply functions comprise:

splitting each of the plurality of spread spectrum RF emissions into an in-phase component and a delayed component; and

multiplying the in-phase and delayed components of a respective split spread spectrum RF emission to recover a spread spectrum chipping rate for a corresponding spread spectrum RF emission.