Abstract:

Regarding to the difficulty of assessing the impact of attitude instability on the orbit, the simulation experiment has been designed to solve this problem, the attitude model of JASON-2 altimeter satellite is discussed, and the mathematical expression for effect of attitude variation on observational data is deduced. The simulation experiment results show that with the attitude instability increases gradually, orbit accuracy will accordingly drop rapidly. Another effect of attitude instability on the orbit accuracy embodies that attitude instability in different axis will have different impact on orbit accuracy. Therefore, to obtain high-accuracy orbit, the satellite attitude stability needs to meet certain requirement, especially for the coordinate axis with a bigger phase center bias. Taking JASON-2 for instance, the attitude variation should be smaller than 2° in this axis. JASON-2based actual measured calculation shows that attitude variation is around 1°, with an effect of 0.036 m on orbit accuracy. This simulation experiment has provided a feasible way for assessing the influence of attitude stability on accurate orbit for China HY-2 altime
ter satellite.

Key words: accuracy analysis, attitude, phase center, JASON-2, precise orbit determination