On-orbit efficient calibration method for remote sensing camera based on trace invariance.

The on-orbit calibration for optical parameters of the space camera is the key to guaranteeing the imaging quality and navigation accuracy. The conventional on-orbit calibration methods are generally constructed based on the star angular distance invariance, which has high computational complexity, due to the complex matrix operation process. The computational and storage resources of spacecraft are severely limited, and the method is hard to realize. This paper proposes an efficient calibration method for the space camera. The core step is to solve the trace of the star matrix constructed by the observed star vectors. The computation process is essentially the addition of several scalars, and it is easier to compute than other calibration models. Besides, the traditional extended Kalman filtering algorithm needs to invert the high-order matrix, which is difficult to autonomously realize on spacecraft with severe resource constraints. The sequential extended Kalman filtering algorithm can avoid the problem, which can quickly and efficiently estimate the optical parameters. Simulation results demonstrate that the internal calibration eliminates most imaging distortion and provides an accurate mapping relationship between the imaging points and the observational direction of the target, with high computational efficiency and calibration accuracy.