Joint angle, frequency and delay estimation method in anti-interference GPS receiver

The Global Navigation Satellite System (GNSS) is widely used, but the satellites are far from the ground, so the signal is weak and susceptible to interference. The traditional method of power inversion algorithm uses space-time cascading, which can only form one beam for all navigation satellites, limiting the performance of interference suppression. Taking GPS as an example, this paper proposes an anti-interference receiver structure based multi-antenna which include two stage: the acquisition stage and tracking stage. In the acquisition stage, interference space is selected after subspace decomposition. Then the received signal is projected into a space orthogonal to the interference space. Next, the angle and fractional frequency offset can be estimated using the periodicity of the satellite signal. At last, beamforming each satellite separately, the delay and integer frequency offset can be estimated. In the tracking stage, comparing to the single-antenna tracking loop which only track frequency offset and delay, an angle loop is added to simultaneously track the angle. In addition, the computational complexity is quantitatively analyzed. Compared to other anti-jamming algorithm without tracking angle, the complexity of the proposed algorithm is less. Finally, the simulation results show that the angle estimation performance of the acquisition stage is improved, the acquisition probability is increased, and the incident angle of the satellite signal can be effectively tracked. The anti-interference ability is also improved greatly compared with the traditional power inversion method.