高动态场景下GNSS信号自适应载波跟踪算法

Compared with urban application scenarios, Global Navigation Satellite System (GNSS) navigation receivers that are mounted on high-speed aircraft must handle a higher carrier frequency dynamic and output the measured result at a higher frequency. Both these factors adversely affect the accuracy of the carrier frequency measurement. Herein, we propose an adaptive carrier-tracking algorithm to measure the radial velocity by introducing a fuzzy logic controller in the carrier-tracking loop. The proposed algorithm adaptively adjusts the loop bandwidth as the carrier frequency changes, improving the velocity measurement accuracy while ensuring dynamic adaptability. Herein, the measured result of the loop is used to calculate the input variables of the fuzzy controller, and the output of the fuzzy controller is used to adjust the loop bandwidth. The fuzzy controller adopts a single input and single output Takagi-Sugeno model, which is easy to implement. The analysis and simulation are performed under fixed-, linear-, and sine-shaped Doppler frequency scenarios. The radial velocity between the aircraft and the receiver is set in the range of ±10 km/s, and the radial acceleration is set in the range of ±30g. To ensure the validity of the measurement results, we output the measurement results at a frequency of 1000 points per second. Simulation results demonstrate that when the input carrier-to-noise ratio is 40 dB Hz, the velocity accuracy of the proposed algorithm is better than 0.3 m/s (1σ).