Frank V

Occupation：SMS Broadcaster LV.1

Introduction：GPS receiver and method for detecting a signal jammer using fast fourier transform. A global positioning system (GPS) receiver and method are provided for detecting a jammer signal using fast Fourier transform (FFT). A correlator correlates GPS signals received from GPS satellites with codes based on a plurality of carrier frequency signals having predetermined frequency offsets therebetween, and computes n correlated samples associated with each of the GPS satellites. A memory stores the n correlated samples associated with each of the GPS satellites and n FFT bins corresponding thereto. A FFT processor transforms the n correlated samples read from the memory using n-point FFT to obtain the n FFT bins, and transfers the n FFT bins to the memory.

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GPS receiver and method for detecting a signal jammer using fast fourier transform

2022-02-12 18:07:20 Author：Frank PV(81441)

A global positioning system (GPS) receiver and method are provided for detecting a jammer signal using fast Fourier transform (FFT). A correlator correlates GPS signals received from GPS satellites with codes based on a plurality of carrier frequency signals having predetermined frequency offsets therebetween, and computes n correlated samples associated with each of the GPS satellites. A memory stores the n correlated samples associated with each of the GPS satellites and n FFT bins corresponding thereto. A FFT processor transforms the n correlated samples read from the memory using n-point FFT to obtain the n FFT bins, and transfers the n FFT bins to the memory. A peak detector detects largest peaks exceeding a lowered detection threshold from the FFT bins associated with each of the GPS satellites. A jammer detection unit makes a determination as to whether a peak relatively far away from other peaks is present among the largest peaks, and detects a signal of a peak far away from other peaks.

A method for detecting a jammer signal using fast Fourier transform (FFT) in a global positioning system (GPS) receiver, comprising: correlating GPS signals received from GPS satellites with codes based on a plurality of carrier frequency signals having predetermined frequency offsets therebetween, and computing n correlated samples associated with each of the GPS satellites; transforming the n correlated samples associated with each of the GPS satellites using n-point FFT to output n FFT bins; detecting largest peaks exceeding a lowered detection threshold from the FFT bins associated with each of the GPS satellites; and making a determination as to whether a peak relatively far away from other peaks is present among the largest peaks, and detecting, as a jammer signal, a signal of a peak far away from other peaks.

A global positioning system (GPS) receiver for detecting a jammer signal using fast Fourier transform (FFT), comprising: a correlator for correlating GPS signals received from GPS satellites with codes based on a plurality of carrier frequency signals having predetermined frequency offsets therebetween, and computing n correlated samples associated with each of the GPS satellites; a memory for storing the n correlated samples associated with each of the GPS satellites and n FFT bins corresponding thereto; a FFT processor for transforming the n correlated samples read from the memory using n-point FFT to obtain the n FFT bins, and transferring the n FFT bins to the memory; a peak detector for detecting largest peaks exceeding a lowered detection threshold from the FFT bins associated with each of the GPS satellites; and a jammer detection unit for making a determination as to whether a peak relatively far away from other peaks is present among the largest peaks, and detecting, as a jammer signal, a signal of a peak far away from other peaks.

With the development of technology, personal portable communication is rapidly developing, and various supplementary services are being supported. Some countries have enacted laws stating that mobile terminals must be equipped with a global positioning system (GPS) device. It is a trend that various location-based services are providing to many mobile terminals. Many GPS satellites broadcast ephemeris and system time information while orbiting the earth, such that GPS receivers can determine their positions. The GPS receivers can accurately determine their positions by computing the arrival times of GPS signals simultaneously transmitted from at least four satellites.

This procedure requires several minutes. More specifically, a compact GPS receiver with a limited amount of battery power cannot perform the above-mentioned procedure for a long period of time. Accordingly, some GPS receivers receive, from an assisted GPS (AGPS) server, basic Doppler information, that is, coarse code phase values and coarse Doppler values, necessary for a search. Multiple satellites must be able to simultaneously observe a GPS receiver, and the GPS receiver must receive high-quality signals from the satellites. Because many portable or mobile devices may not be equipped with high-quality antennas, and/or may be located within forested areas and buildings, it is not easy for the portable devices to receive high-quality signals.

The above and other aspects of the present invention can be achieved by a method for detecting a jammer signal using fast Fourier transform (FFT) in a global positioning system (GPS) receiver, comprising correlating GPS signals received from GPS satellites with codes based on a plurality of carrier frequency signals having predetermined frequency offsets therebetween, and computing n correlated samples associated with each of the GPS satellites and transforming the n correlated samples associated with each of the GPS satellites using n-point FFT to output n FFT bins. The method further comprises detecting largest peaks exceeding a lowered detection threshold from the FFT bins associated with each of the GPS satellites and making a determination as to whether a peak relatively far away from other peaks is present among the largest peaks, and detecting, as a jammer signal, a signal of a peak far away from other peaks.

The above and other aspects of the present invention can be achieved by a global positioning system (GPS) receiver for detecting a jammer signal using fast Fourier transform (FFT), comprising a correlator for correlating GPS signals received from GPS satellites with codes based on a plurality of carrier frequency signals having predetermined frequency offsets therebetween, and computing n correlated samples associated with each of the GPS satellites and a memory for storing the n correlated samples associated with each of the GPS satellites and n FFT bins corresponding thereto. The apparatus further comprises a FFT processor for transforming the n correlated samples read from the memory using n-point FFT to obtain the n FFT bins, and transferring the n FFT bins to the memory, a peak detector for detecting largest peaks exceeding a lowered detection threshold from the FFT bins associated with each of the GPS satellites and a jammer detection unit for making a determination as to whether a peak relatively far away from other peaks is present among the largest peaks, and detecting, as a jammer signal, a signal of a peak far away from other peaks.

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