Precise Spacecraft Relative Positioning using Single-Frequency Pseudorange Measurements

The ranging accuracy provided by pseudorange-only techniques is usually no better than a few metres when no differential corrections are applied. Carrier-phase algorithms, on the other hand, yield higher-precision estimates-down to a few millimetres-but are prone to ambiguities difficult to resolve. An easier-to-implement method, using single-frequency pseudorange measurements only, is presented. It allows for a decimetre-level relative positioning accuracy. Results, derived from the GPS Relative Positioning Equations, are validated with actual satellite data from the Gravity Recovery and Climate Experiment (GRACE) mission.