Influence of sampling noise on spread-spectrum ranging based on software defined radio

Increasingly, software defined radio receivers adopting band sampling are widely applied in space mission. In such systems, particularly in spread-spectrum ranging systems, the influence of sampling noise can not be neglected. The paper analyzes the sampling noise, presents its influence on the carrier noise ratio, and derives the ranging error by calculating the synchronization error of the delay locked loop. Simulations aiming at each impact factors of sampling-noise-induced ranging error are performed. Simulation and experiment results show that if the target ranging accuracy is at the level of centimeter, the quantization length should be no less than 8 and the sampling clock jitter should not exceed 60ps.