Design and Implementation of an Intersatellite Coherent Laser Bidirectional Communication and Ranging Integration System

To address the urgent need for new satellite constellations for high-speed communication and high-precision orbit determination, this paper designs an intersatellite heterodyne coherent laser mixed-domain integrated communication and ranging system, achieving deep integration of communication and ranging functions. The system combines analog-domain linear equalization with a digital-domain feedback mechanism to establish an integrated processing strategy for clock and data recovery (CDR), along with high-precision ranging. A phase-augmented pseudo-noise ranging dual one-way ranging (PAPR-DOWR) scheme is implemented, which accurately accomplishes intersatellite distance resolution through the synergy between coarse measurements via frame-synchronization matched filtering and fine measurements via an optimized Gardner timing recovery algorithm.Thetest platform of the on-orbit experiment is a medium Earth orbit (MEO) satellite at an altitude of approximately 20,000 km, the two laser terminals under test are separated by approximately 50,000 km, and the Doppler frequency shift is within ±5 GHz. The experimental results show that at a symbol rate of 1.023 Gsps, the system achieves ranging standard deviations of 4.39 ps (approximately 1.3 mm, 1σ) in a ground-based 4000 s long-term test and 5.69 ps (approximately 1.7 mm, 1σ) in an on-orbit short-term dynamic test, fully demonstrating millimeter-level ranging performance under long-distance, low-SNR intersatellite conditions.