Abstract: Pseudo-range and phase measurement data received by onboard global positioning system (GPS) satellite receiver are broadly used in satellite orbit measurement. However, while GPS signals are received, the measurement auxiliary data signal strength (E) of receiving data  are received at the same time by the receiver. Theoretical analysis indicates that there is a strong correlation between the signal strength (E) of receiving data  and signal antenna angle α. If a strong correlation prior model between E and α is established, α can be calculated by E. In spacecraft missions, the relative positions of spacecraft and GPS satellites are known. The attitude of receiving antenna of onboard GPS satellite receiver can be calculated by three or more α of GPS satellite signal antenna during a fixed time. The accuracy of attitude determination is determined by the stability of the prior model. The observed and calculated data of the CHAMP satellite show that the accuracy for initial attitude determination is about 2°~3°. 

Key words: Attitude determination, Global positioning system, Signal strength, Satellite