| Abstract: | We analyze the post-fit residuals of one-way Doppler tracking data from the Mars Express(MEX) spacecraft to test possible violations of local Lorentz invariance(LLI) and local position invariance(LPI).These one-way Doppler observations were carried out on 2011 August 7 for about 20 minutes at Sheshan Station of Shanghai Astronomical Observatory in China.These downlink signals were sent by MEX for telemetry at X-band.Because we are not able to decode the data in the form of telemetry and separate them from the carrier frequency,this makes the post-fit residuals of the Doppler data degrade to the level of 0.1 m s~(-1).Even so,the residuals can still impose upper bounds on LLI and LPI at 10~(-1),which is consistent with the prediction based on our analysis of the detectability.Although the upper bounds given by three-way Doppler tracking of MEX are better than those obtained in the present work,one-way Doppler measurements still provide a unique chance to test possible violations of LLI and LPI far from the ground stations. |
