System, method, and storage medium for design and use reference emitters to enhance passive single satellite geolocation of EMI sources

Patent metadata

Field	Value
Publication number	US-12386016-B2
Application number	US-202318161014-A
Country	US
Kind code	B2
Filing date	Jan 27, 2023
Priority date	Jan 27, 2023
Publication date	Aug 12, 2025
Grant date	Aug 12, 2025

Abstract

The present disclosure provides a cross-correlation based method, a system and a storage medium for blind electromagnetic interference Doppler estimation from a single satellite geolocation system. The method includes at a first time, calculating a power spectral density (PSD) of a received signal; smoothing the PSD of the received signal using moving window average, and saving the smoothed PSD of the received signal as PSD0; at a next time, calculating a PSD of another received signal; smoothing the PSD of the another received signal using moving window average, and saving the smoothed PSD of the another received signal as PSD1; performing cross correlation between PSD0 and PSD1 to obtain a cross-correlation result; determining a peak position from the cross-correlation result; and obtaining a Doppler estimation based on a peak position shift between the peak position and a reference position.

First claim

What is claimed is:

1. A cross-correlation based method for blind electromagnetic interference (EMI) Doppler estimation from a single satellite geolocation (SSG) system, comprising:
at a first time, calculating a power spectral density (PSD) of a received signal; smoothing the PSD of the received signal using a moving window average approach, and saving the smoothed PSD of the received signal as PSD0;
at a next time, calculating a PSD of another received signal; smoothing the PSD of the another received signal using the moving window average approach, and saving the smoothed PSD of the another received signal as PSD1;
performing cross-correlation between PSD0 and PSD1 to obtain a cross-correlation result;
determining a peak position from the cross-correlation result; and
obtaining a Doppler estimation based on a peak position shift between the peak position and a reference position.

2. The method according to claim 1 , wherein:
Doppler rate estimation is calculated according to the obtained Doppler estimation.

3. The method according to claim 2 , wherein performing an online ionosphere estimation includes:
estimating an ionospheric delay for an enhanced reference emitter (ERE); estimating slant total electron content (STEC) using the ionospheric delay for the ERE; and estimating an ionospheric delay for an EMI source using the STEC.

4. The method according to claim 3 , wherein:
the ERE has dual operation modes which include an offline mode and an online mode, wherein the ERE is configured to mimic the EMI source at the offline mode and compensate the ionospheric delay at the online mode.

5. The method according to claim 1 , wherein:
before calculating the PSD of the received signal, the method further includes performing fast Fourier transform (FFT) on the received signal; and/or
before calculating the PSD of the another received signal, the method further includes performing fast Fourier transform (FFT) on the another received signal.

6. A system, comprising:
a memory, configured to store program instructions for performing a cross-correlation based method for blind electromagnetic interference (EMI) Doppler estimation from a single satellite geolocation (SSG) system; and
a processor, coupled with the memory and, when executing the program instructions, configured for:
at a first time, calculating a power spectral density (PSD) of a received signal;
smoothing the PSD of the received signal using moving window average, and saving the smoothed PSD of the received signal as PSD0;
at a next time, calculating a PSD of another received signal; smoothing the PSD of the another received signal using moving window average, and saving the smoothed PSD of the another received signal as PSD1;
performing cross-correlation between PSD0 and PSD1 to obtain a cross-correlation result;
determining a peak position from the cross-correlation result; and
obtaining a Doppler estimation based on a peak position shift between the peak position and a reference position.

7. The system according to claim 6 , wherein:
Doppler rate estimation is calculated according to the obtained Doppler estimation.

8. The system according to claim 7 , wherein for performing an online ionosphere estimation, the processor is configured to:
estimate an ionospheric delay for an enhanced reference emitter (ERE); estimate slant total electron content (STEC) using the ionospheric delay for the ERE; and estimate an ionospheric delay for an EMI source using the STEC.

9. The system according to claim 8 , wherein:
the ERE has dual operation modes which include an offline mode and an online mode, wherein the ERE is configured to mimic the EMI source at the offline mode and compensate the ionospheric delay at the online mode.

10. The system according to claim 6 , wherein:
before calculating the PSD of the received signal, the processor is configured to perform fast Fourier transform (FFT) on the received signal; and/or
before calculating the PSD of the another received signal, the processor is configured to perform fast Fourier transform (FFT) on the another received signal.

11. A non-transitory computer-readable storage medium, containing program instructions for, when being executed by a processor, performing a cross-correlation based method for blind electromagnetic interference (EMI) Doppler estimation from a single satellite geolocation (SSG) system, the method comprising:
at a first time, calculating a power spectral density (PSD) of a received signal; smoothing the PSD of the received signal using moving window average, and saving the smoothed PSD of the received signal as PSD0;
at a next time, calculating a PSD of another received signal; smoothing the PSD of the another received signal using moving window average, and saving the smoothed PSD of the another received signal as PSD1;
performing cross-correlation between PSD0 and PSD1 to obtain a cross-correlation result;
determining a peak position from the cross-correlation result; and
obtaining a Doppler estimation based on a peak position shift between the peak position and a reference position.

12. The storage medium according to claim 11 , wherein:
Doppler rate estimation is calculated according to the obtained Doppler estimation.

13. The storage medium according to claim 12 , wherein for performing an online ionosphere estimation, the processor is configured to:
estimate an ionospheric delay for an enhanced reference emitter (ERE); estimate slant total electron content (STEC) using the ionospheric delay for the ERE; and estimate an ionospheric delay for an EMI source using the STEC.

14. The storage medium according to claim 13 , wherein:
the ERE has dual operation modes which include an offline mode and an online mode, wherein the ERE is configured to mimic the EMI source at the offline mode and compensate the ionospheric delay at the online mode.

15. The storage medium according to claim 11 , wherein:
before calculating the PSD of the received signal, the processor is configured to perform fast Fourier transform (FFT) on the received signal; and/or
before calculating the PSD of the another received signal, the processor is configured to perform fast Fourier transform (FFT) on the another received signal.

Assignees

• Intelligent Fusion Tech Inc

Inventors

• Shen Dan
• Chen Genshe
• Pham Khanh

Classifications

• G01S5/0294

  Trajectory determination or predictive filtering, e.g. target tracking or Kalman filtering · CPC title

• G01S5/021

  Calibration, monitoring or correction (G01S5/0252 takes precedence) · CPC title

• G01S5/0249

  Determining position using measurements made by a non-stationary device other than the device whose position is being determined · CPC title

• G01S5/0246 Primary

  involving frequency difference of arrival or Doppler measurements (G01S5/02685 takes precedence) · CPC title