关键词: 卫星, 扩频信号, 快速捕获, 动态, 快速傅氏变换法

Abstract: In the present satellite navigation applications, the global navigation satellite system (GNSS) receiver must be able to work well at large dynamic environment. In order to capture rapidly satellite navigation signals at the large frequency deviation, this paper presents an improved Bi-Frequency domain calculation method which could parallel search code phase and Doppler shift. First, long correlation integral operation is divided into short correlation integration operation with double block zeros padding (DBZP) algorithm, quickly searching code phase with circular correlation combined with Fast Fourier Transform(FFT), significantly reducing the amount of computation. Then the amount of computation is largely reduced with equivalence principle of the frequency domain circular shift and time domain carrier peeling. Compared with continuous acquisition algorithms and single frequency domain acquisition algorithm under the same acquisition sensitivity conditions, operation time reduces 90%. It is suitable for rapid acquisition of GPS signals under large deviation conditions. Experiments show that the method can capture GPS signal ±500kHz within 0.1s.

Key words: Satellite, Navigation signal, Rapid acquisition, Dynamic, FFT