The local carrier optimization technology in anti-jamming satellite navigation receiver

Carrier numerically controlled oscillator (NCO) is a key part of the navigation receiver to strip the carrier of the received signal. In the digital signal processing module, the numerically controlled oscillator quantizes the amplitude and frequency of the local carrier signal through the quantization width and addressing word. The local carrier is designed by the bit width and depth of the memory data. Under the dynamic range of given input signal/interference, this paper optimizes the design of the quantization width and addressing length of the read-only memory (ROM) in the NCO according to the characteristics of the local carrier, adapting it to the actual engineering requirement, which avoids the redundancy of local carrier storage while ensuring the performance of signal-to-noise ratio (SNR) and frequency accuracy. The experimental results show that designing the optimal quantization width and addressing word of the navigation receiver local carrier based on the requirements can ensure the digital down-conversion SNR ratio loss less than 0.1 dB, the relative error of the actual output frequency of the local carrier less than 0.1%, and the optimal quantization width and addressing word less than the value before optimization. The storage resource occupancy rate was reduced, and the adaptability of the local carrier signal under dynamic signals and interference was effectively improved.