Velocity estimation of rock-fall in multi-channel SAR system with low PRF sampling

Rockfalls influence the safety of the surrounding infrastructure and the normal operation of transportation lines. The application of synthetic aperture radar (SAR) technology is a new method of rock-fall monitoring and disaster prediction. This paper introduces a novel method to velocity estimation of rock-fall target utilizing SAR with low pulse repetition frequency (PRF) sampling. As is known to us, when PRF is less than the Doppler spectrum bandwidth, rock-fall target suffer both Doppler centroid frequency ambiguity and Doppler spectrum ambiguity. Under this condition, the traditional velocity estimation method in the Doppler domain is out of action. To solve above problem, this paper designs an improved reconstruction filter bank to reconstruct the Doppler spectrum of rock-fall target, and then Doppler in-band energy and Doppler out-of-band energy ratio of rock-fall target is utilized to estimate the velocity of rock-fall target. Simulation experiment results show the effectiveness of proposed method.