Method and apparatus for adjusting threshold weight of frequency domain to improve anti-jamming performance and eliminate jamming in GPS system

Patent metadata

Field	Value
Publication number	US-9651670-B2
Application number	US-201013576818-A
Country	US
Kind code	B2
Filing date	Nov 4, 2010
Priority date	Feb 18, 2010
Publication date	May 16, 2017
Grant date	May 16, 2017

Abstract

A method and apparatus for improving anti-jamming performance are provided. A threshold value level estimated in a GPS (global positioning system) receiver RF/IF stage, a threshold value weight, a median value of a median value of a 2˜8 MHz bandwidth is estimated as a threshold value with respect to a frequency component exceeding the estimated threshold value level, and an adjustable K-median threshold scheme is provided in a multi-jamming environment.

First claim

The invention claimed is:

1. An adjustable GPS jamming elimination method implemented by a jamming excisor, the method comprising:
converting a signal received from a reception antenna to a signal in a frequency domain;
determining a jamming signal in an in-band spectrum of the converted signal in the frequency domain;
setting initially an estimated threshold value for anti jamming filtering;
selecting a median value in a frequency domain of the jamming signal;
determining a conclusive threshold value by applying the estimated threshold value to an adjustable threshold value based on an amplitude of the median value; and
determining whether to eliminate an individual bin of the jamming signal as an interference frequency component based on the conclusive threshold value.

2. The method of claim 1 , wherein the adjustable threshold value is obtained by using a JNR (jamming to noise ratio) gain that corresponds to a ratio between the amplitude of the median value and nose of a receiver.

3. The method of claim 2 , wherein the adjustable threshold value is divided into four stages based on the amplitude of the median value.

4. The method of claim 2 , further comprising:
when the JNR gain is 10 dB or smaller, setting the adjustable threshold value as 4;
when the JNR gain exceeds 10 dB, determining whether or not the JNR gain exceeds 25 dB, and when the JNR gain is 25 dB or lower, setting the adjustable threshold value as 3, and when the JNR gain exceeds 25 dB, determining whether or not the JNR gain exceeds 40 dB; and
when the JNR gain is 40 dB or lower, setting the adjustable threshold value as 2, and when the JNR gain exceeds 40 dB, setting the adjustable value as 1.

5. The method of claim 1 , wherein the median value is a median value of an in-band spectrum of a received signal.

6. The method of claim 5 , wherein the received signal is a signal received from one or more of a GPS system, a GLONASS system, and a Galileo system.

Assignees

• Kim Jun O
• Bae Jun Seoung
• Song Ki Won
• Agency Defense Dev

Inventors

• Kim Jun O
• Bae Jun Seoung
• Song Ki Won

Classifications

• G01S19/21 Primary

  Interference related issues {; Issues related to cross-correlation, spoofing or other methods of denial of service} · CPC title

• H04B1/7102

  with transform to frequency domain · CPC title

• H04K3/228

  Elimination in the received signal of jamming or of data corrupted by jamming (interference suppression in receivers H04B1/10) · CPC title

• G01S19/015

  Arrangements for jamming, spoofing or other methods of denial of service of such systems · CPC title

• H04K3/90

  related to allowing or preventing navigation or positioning, e.g. GPS · CPC title