Method of Code Tracking Loop Bandwidth Stabilization Adjustment for Inter-satellite Ranging System

Abstract

In the inter-satellite ranging system based on pseudorandom code ranging, if delay lock loop (DLL) which is used for code tracking adopts fixed loop parameters, then a compromise must be made between tracking precision and dynamic performance. In order to overcome this shortcoming, this paper proposes a method of adjusting the loop bandwidth adaptively and steadily. The code tracking error, loop carrier-to-noise power ratio and dynamic stress are monitored in real time. Then the loop bandwidth is adjusted on the principle of minimizing the code tracking error. In the meanwhile, a series of limiting factors during bandwidth adjustment are taken into full consideration. As a result, the loop responds quickly to burst dynamic stress and ensures stable tracking throughout the bandwidth adjustment process. Finally, the validity of this method is verified by MATLAB simulations. The simulation results show that this method is stable in the case of burst dynamic stress and during bandwidth adjustment process. The need of tracking precision and dynamic performance are both taken into account.