Draconitic periodic signals have been widely found in diverse GPS products. In this contribution, we quantified the draconitic errors in station coordinate and investigated how to reduce them. We evaluated and compared the draconitic errors in IGS operational coordinates, as well as the first and second reprocessed coordinates. Results show that the draconitic errors become more prominent in the two reprocessing campaigns, as the precision of the coordinates are improved. The odd draconitic errors in the second reprocessing campaign are reduced compared to the first one, which may be attributed to the adoption of the Earth radiation pressure. We also calculated the coordinate time series of 150 IGS stations from 2001 to 2015 in PPP mode by PANDA software, using IGS second reprocessed precise orbit and clock products. For the data processing, the improved strategy and session length are adopted to study their effect on the draconitic errors.