Navigation system with embedded software defined radio

Patent metadata

Field	Value
Publication number	US-12235367-B2
Application number	US-202217953512-A
Country	US
Kind code	B2
Filing date	Sep 27, 2022
Priority date	Sep 27, 2022
Publication date	Feb 25, 2025
Grant date	Feb 25, 2025

Abstract

Techniques are provided for employing an embedded software defined radio (SDR) in a navigation system. A navigation system implementing the techniques according to an embodiment includes a global positioning system (GPS) receiver configured to acquire and track received GPS signals. The system also includes an SDR configured to process received communication signals. The communication signals include timing data. The SDR is further configured to calculate position and navigation data based on a combination of the processed communication signals and the tracked GPS signals provided by the GPS receiver. The system further includes a system timer configured to provide a common time base for use by the GPS receiver and the SDR. The navigation system is implemented in an application specific integrated circuit (ASIC).

First claim

What is claimed is:

1. A navigation system comprising:
a global positioning system (GPS) receiver configured to acquire and track received GPS signals;
a software defined radio (SDR) configured to process received communication signals that include timing data, the SDR further configured to calculate position and navigation data based on a combination of the processed communication signals and the tracked GPS signals provided by the GPS receiver; and
a system timer configured to provide a common time base for use by the GPS receiver and the SDR.

2. The navigation system of claim 1 , wherein the SDR comprises a data timestamping circuit configured to group in-phase (I) and quadrature (Q) samples of the received communications signals into IQ data blocks, generate a timestamp for each of the IQ data blocks, and store the IQ data blocks and associated timestamps into an IQ data circular buffer, wherein the timestamp is based on the common time base.

3. The navigation system of claim 2 , wherein the SDR further comprises a signal detection co-processor configured to:
perform a two-dimensional correlation based search of the received communication signals for software defined signal patterns, the two dimensions including doppler frequency and time offset; and
store candidate search results in a detection data buffer, wherein the candidate search results include an IQ data block identifier, a sample index, a doppler value, and a signal strength, wherein the IQ data block identifier and the sample index provide a location in the IQ data circular buffer of IQ samples of the received communications signals associated with the candidate search results.

4. The navigation system of claim 3 , wherein the SDR further comprises a fast Fourier transform (FFT) co-processor configured to transform IQ samples of the received communications signals into frequency domain samples and store the frequency domain samples into FFT data blocks in an FFT data buffer.

5. The navigation system of claim 4 , wherein the SDR comprises a dynamic random access memory configured to store the IQ data circular buffer, the detection data buffer, and the FFT data buffer.

6. The navigation system of claim 5 , wherein the SDR comprises:
a first processor core configured to process the tracked GPS signals to calculate ranges to the GPS satellites; and
a second processor core configured to:
provide the software defined signal patterns to the signal detection co-processor,
control the FFT co-processor,
calculate ranges to sources of the communication signals based on data stored in one or more of the IQ data circular buffer, the detection data buffer, and the FFT data buffer, and
calculate position and navigation data based on a combination of the calculated ranges to the GPS satellites and the calculated ranges to the sources of the communication signals, the position and navigation data for use by navigational applications.

7. The navigation system of claim 1 , wherein the SDR comprises processor cores configured to decode the received communication signals for use by applications other than navigational applications.

8. The navigation system of claim 1 , wherein the system timer comprises a frequency reference, a phase locked loop (PLL), and a high resolution timer.

9. A computer program product including one or more non-transitory machine-readable mediums encoded with instructions that when executed by one or more processors cause a process to be carried out for communication and navigation, the process comprising:
providing a common time base for use by a global positioning system (GPS) receiver and a software defined radio (SDR);
acquiring and tracking, by the GPS receiver, GPS signals received from GPS satellites;
processing, by the SDR, received communication signals that include timing data; and
calculating, by the SDR, position and navigation data based on a combination of the processed communication signals and the tracked GPS signals.

10. The computer program product of claim 9 , wherein the process further comprises grouping in-phase (I) and quadrature (Q) samples of the received communications signals into IQ data blocks, generating a timestamp for each of the IQ data blocks, and storing the IQ data blocks and associated timestamps into an IQ data circular buffer, wherein the timestamp is based on the common time base.

11. The computer program product of claim 10 , wherein the process further comprises:
performing a two-dimensional correlation based search of the received communication signals for software defined signal patterns, the two dimensions including doppler frequency and time offset; and
storing candidate search results in a detection data buffer, wherein the candidate search results include an IQ data block identifier, a sample index, a doppler value, and a signal strength, wherein the IQ data block identifier and the sample index provide a location in the IQ data circular buffer of IQ samples of the received communications signals associated with the candidate search results.

12. The computer program product of claim 11 , wherein the process further comprises transforming IQ samples of the received communications signals into frequency domain samples and storing the frequency domain samples into FFT data blocks in an FFT data buffer.

13. The computer program product of claim 12 , wherein the process further comprises:
processing the tracked GPS signals to calculate ranges to the GPS satellites;
calculating ranges to sources of the communication signals based on data stored in one or more of the IQ data circular buffer, the detection data buffer, and the FFT data buffer, and
calculating position and navigation data based on a combination of the calculated ranges to the GPS satellites and the calculated ranges to the sources of the communication signals, the position and navigation data for use by navigational applications.

14. The computer program product of claim 9 , wherein the process further comprises decoding the received communication signals for use by applications other than navigational applications.

15. A method for communication and navigation, the method comprising:
providing a common time base for use by a global positioning system (GPS) receiver and a software defined radio (SDR);
acquiring and tracking, by the GPS receiver, GPS signals received from GPS satellites;
processing, by the SDR, received communication signals that include timing data; and
calculating, by the SDR, position and navigation data based on a combination of the processed communication signals and the tracked GPS signals.

16. The method of claim 15 , further comprising grouping in-phase (I) and quadrature (Q) samples of the received communications signals into IQ data blocks, generating a timestamp for each of the IQ data blocks, and storing the IQ data blocks and associated timestamps into an IQ data circular buffer, wherein the timestamp is based on the common time base.

17. The method of claim 16 , further comprising:
performing a two-dimensional correlation based search of the received communication signals for software defined signal patterns, the two dimensions including doppler frequency and time offset; and
storing candidate search results in a detection data buffer, wherein the candidate search results include an IQ data block identifier, a sample index, a doppler value, and a signal strength, wherein the IQ data block identifier and the sample index provide a location in the IQ data circular buffer of IQ samples of the received communications signals associated with the candi

Assignees

• Bae Sys Inf & Elect Sys Integ

Inventors

• Acheson John E
• Kloos Michael N
• James Nathaniel L
• Dennis Mitchell

Classifications

• G01S19/14 Primary

  specially adapted for specific applications · CPC title

• G01S19/35

  Constructional details or hardware or software details of the signal processing chain · CPC title

• G01S19/46

  the supplementary measurement being of a radio-wave signal type · CPC title

• G01S19/37 Primary

  Hardware or software details of the signal processing chain · CPC title