Research on Open-Loop Measurement Technique for Spacecraft

Abstract

In order to solve the problem that Phase-Locked loop tracking measurement technique losses lock when the SNR is low or dynamic range is high, we do the research of spacecraft open-loop measurement technique without Phase-Locked loop. Open-Loop measurement technique includes Open-Loop data reception and data processing technique. Spacecraft Open-Loop distance measurement technique mainly adopts preset frequency band, FFT analysis, high-intermediate frequency or RF collection technique. Spacecraft Open-Loop data processing mainly includes Open-Loop Doppler data processing and Open-Loop distance measurement data processing. With high accuracy estimation and compensation for Doppler and Doppler rate, the random error of Open-Loop Doppler and distance measurement is about an order of magnitudes better than Closed-Loop. Open-Loop measurement technique has the disadvantage of complicated algorithms and huge amount of calculation, so it can’t be implemented on the present FPGA. As a result, the paper presents a method to implement Open-Loop measurement technique.