Open loop doppler tracking in Chinese forthcoming Mars mission

Using the radio telescopes in Chinese VLBI Network and the K5/VSSP32 VLBI system of NICT in Japan, we have developed algorithms that can extract open loop Doppler information from the ChangʹE-1 and Mars Express radio tracking data. Our latest results indicate the Doppler accuracy of open loop three-way Doppler is about 1mm/s in 1 second integration time, relative to a 8.4GHz carrier. In the forthcoming joint Russian-Chinese Martian mission in 2009, the current software algorithms and hardware performance will be improved, and we will attempt to use the high precision Doppler shift and phase information to test gravitation theories.