Precise and Rapid Recovery of the Earth's Gravitational Field by the Next‐Generation Four‐Satellite Cartwheel Formation System

Abstract

AbstractFirstly, the orbital stability design of the next‐generation gravity satellite formation is very important for precisely developing the Earth gravity field model with high spatial resolution. Therefore, for the sake of guaranteeing the stability of the next‐generation Four‐Satellite Cartwheel Formation (FSCF), the optimal design of the orbital elements is proposed as follows: (1) the semimajor axis a, orbital eccentricity e, orbital inclination i and longitude of ascending node Ω keep invariant; (2) the argument of perigee ω and mean anomaly M need to have a discrepancy of 180°, respectively; (3) the initial argument of perigee ω should be set at the equator, and the initial mean anomaly must be designed at the poles; (4) the ratio between semimajor and semiminor axes from the elliptical orbit of the satellite formation system is 2:1. Secondly, the Earth's gravitational field from the next‐generation FSCF complete up to degree and order 120 is accurately and rapid recovered based on the intersatellite range‐rate interpolation method using the correlation coefficients (0.85 in intersatellite range‐rate of the interferometric laser ranging system, 0.95 in orbital position and velocity of the GPS receiver, and 0.90 in non‐conservative force of the accelerometer), an observation time of 30 days and a sampling interval of 10 s, and cumulative geoid height error is 1.162×10−4 m at degree 120, which is at least one order of magnitude higher than the accuracy of the Earth's gravitational field from GRACE. Finally, the advantages of the next‐generation FSCF are the lower orbital altitude, the higher observation accuracy, the full‐tensor observations, the weak aliasing effects, and the strong time‐varying signals.