GPS接收機抗窄頻干擾之頻域設計
Design of Narrowband Anti-jamming GPS Receivers in Frequency Domain
Date Issued
2004
Date
2004
Author(s)
Su, Tsang-Hung
DOI
en-US
Abstract
Abstract
GPS is an accurate navigating system and generally used in civilian or military applications. But GPS receiver performance is usually degraded by intentional or unintentional RF interference. The jamming signal may cause the navigation error and even saturate the receiver.
This thesis focuses on the cancellation of narrowband jamming. Excising method in frequency domain is our architecture in the anti-jamming studies. Fast Fourier transform (FFT) can translate time sequence after A/D converter to frequency domain Excision processing removes jamming power in the spectrum. Inverse fast Fourier transform (IFFT) reconstruct the time sequence after jamming excision.
We use System View, a powerful communication software package, to generate the GPS signals, PRN codes, thermal noise and jamming signals, etc. The jamming method, despread and demodulation operations are also constructed by the same software package. The simulation can shows that overlap fast Fourier transform (OFFT) is a powerful approach to reject the narrowband interference. After anti-jamming processing, the signal to noise ration (SNR) is improved. So, GPS receiver can get navigation data successfully.
In order to implement the hardware circuits, we choose Altera Stratix FPGA EP1S25 F780C5 to build three main blocks (FFT, excision and IFFT). Quarstus II can help us to simulate the anti-jamming processing in hardware circuit. Taking a single tone interference as an example to test this hardware implementation, the results are satisfactory.
Subjects
接收機
抗干擾
窄頻干擾
anti-jamming
receiver
Type
thesis
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