The effects of satellite´s spin on doppler measurements

This paper reports the regular variations of the satellite´s spin frequency harmonics during SELENE lunar mission. When the antenna is loaded on a spin satellite, the satellite´s spin frequency, fs, and its harmonics occur and become noise in Doppler measurements. In our project, because both of Rstar and Vstar have octagonal prismatic bodies, the 8th, the 16th and the 24th spin frequency harmonics are relatively stronger than the other ones. The three harmonics´ amplitudes over the entire mission longer than one year varied with a period of 27.32 days (one sidereal month) clearly. Also a low pass filter is used to remove these spin frequency harmonics. Using the 24th spin frequency harmonic, a novel method of estimating the satellite´s spin frequency with an accuracy of 10-4 Hz is developed.