2023, 45(11): 4060-4071.
doi: 10.11999/JEIT230842
Abstract:
The Inter Satellite Links (ISL) is the key for China's Beidou-3 to overcome regional station deployment and achieve high-precision services. Its antenna Phase Center Offsets (PCO) is calibrated on the ground based on satellite mass and designed attitude when the equipment leaves the factory. However, fuel consumption, antenna deployment attitude, and other factors can cause changes in satellite mass and attitude during satellite launch, orbit entry, and in orbit stages, which will result in inconsistent values of antenna phase center deviation in orbit with ground calibration values. This change will be introduced as an error into the measurement value, thereby affecting the accuracy of satellite orbit determination. Therefore, this article studies the calibration method for the PCO of the inter-satellite links of in-orbit satellites. By combining with inter-satellite and satellite-ground observations, an in-orbit estimation method is established based on whole-network estimation. Two weeks of measured data are used to verify for all Medium Earth Orbit satellites (MEO) of Beidou-3, and a detailed analysis of in-orbit characteristics is conducted in conjunction with satellite manufacturers and orbital surfaces. Finally, its impact on the accuracy of orbit determination is verified. Results show that method proposed in this paper can effectively estimate the PCO of the inter-satellite links antenna in-orbit. It is found that the PCO of the inter-satellite links antenna in most in-orbit satellites is basically consistent with the values on the ground. However, C36, C37, C41, and C42 satellites have a deviation of about 15 cm from the ground calibration value in the Z-direction. Satellites C25, C26, C43 and C44 have opposite signs on the Y-direction, and there is a deviation of about 10 cm in the numerical value. Satellite C25, C26 have a deviation of nearly 30 cm in the Z-direction. After correctly calibrating the PCO of the inter-satellite links antenna in-orbit, the orbit accuracy can be improved by 15% compared to ground calibration products.