Effect of temperature on precision of TWSTFT clock comparison in Chinese Area Positioning System

In CAPS, the temperature changes greatly in one day, especially for master station with continental climate by 10 °C. Moreover, there is periodic tendency in temperature and clock offset residuals. The relation between temperature and clock offset residuals should be researched to improve TWSTFT precision. However, there is no explicit model for effect of temperature on clock offset. In order to test the effect of temperature on clock comparison, experiment has been conducted using C-B and observation on 17 June, 2005. There are two TWSTFT links: Shanghai-Linton, Changchun-Linton. The RMS for clock offset residuals between Shanghai and Linton has decreased from 0.6174ns to 0.2771ns, with that being from 0.6445ns to 0.4050ns. The TWSTFT precision has increased by 55% for Shanghai-Linton link and 37% for Changchun-Linton link. Therefore, TWSTFT precision has been improved after temperature compensation. The temperature of each station should be set constant, which is significant for TWSTFT in CAPS.