Estimation of COMPASS on-board clock short-term stability

The short-term frequency stability estimation of GNSS on-board clocks is very important for clock modeling and prediction. Orbit Determination and Time Synchronization (ODTS) method is commonly used to estimate the clock offset, which needs continuous observation by large monitoring ground network and complicate algorithms. COMPASS is on its early stage of construction and has not globally distributed station network for satellites tracking. In this paper, we have analyzed an estimation method based on a single monitoring station observation. Based on this method, a simple method for COMPASS MEO/IGSO on-board clocks estimation using smoothed broadcast ephemeris is presented, and a method for COMPASS GEO on-board clocks estimation using satellite radio ranging (SRR) is also discussed. At the end of this paper, the preliminary estimation results for COMPASS IGSO and GEO on-board clocks by these two methods are presented.