航天器应急姿态捕获中GPS信号的应用

星载全球定位系统（GPS）卫星接收机在测量接收各GPS卫星信号时，可同时得到接收信号的信号强度测量辅助数据E。理论分析表明，接收信号的强度E与信号入射天线的法向夹角α强相关。如建立E与α稳定的先验模型，E就可以作为测量值，计算入射天线的角度α。在同一时刻，通过三个以上GPS卫星信号入射天线的角度α，可计算星载GPS卫星接收机接收天线的空间姿态。确定姿态的精度取决于E与α相关先验模型的稳定性。利用CHAMP卫星星载接收机在轨实测数据检验，估算的初始姿态精度为2°~3°。该方法可作为航天器故障状态下应急姿态捕获的一种辅助手段，也可为携带星载GPS而无高精度定姿要求的简易航天器提供一种新的无附加成本的定姿途径。

GPS Signal Application to Spacecraft Emergent Attitude Acquisition

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°. 