An effective orbit estimation algorithm for a space debris radar using the quasi-periodicity of the evaluation function

Orbit estimation of space debris, which is unnecessary objects orbiting around the earth, is an important task in avoiding the collision with spacecrafts. Kamisaibara Space Guard Center radar system was built in 2004 as the first radar facility devoted to the observation of space debris in Japan. In order to detect smaller debris, it is effective to improve SNR (Signal-to-Noise Ratio) using coherent integration. However it is difficult to apply the coherent integration to the real data because the motion of the target is unknown at the first step. We propose fast algorithms for signal detection and orbit estimation for faint radar echoes from space debris by utilizing the characteristic of the evaluation function. The proposed algorithms improve SNR by 10.62 dB. The error of the range and the Doppler velocity with expected one are 89 m and 21 m/s, respectively.