采用方向余弦矩阵描述姿态,建立GPS/陀螺组合姿态确定系统模型,由矩阵Kalman滤波方法解算整周模糊度的浮点解,然后再利用MC-Lambda方法得到整周模糊度固定解。仿真实验结果表明,附加方向余弦矩阵约束的Kalman滤波方法可以有效地提高整周模糊度浮点解的精度,使得整周模糊度的固定成功率和效率均得到提高,尤其是在GPS观测条件较差的情况下。
One of key issues in the aspect of GPS-based attitude determination that must be solved is to estimate the unknown integer ambiguities. Single-epoch attitude ambiguity resolution can be achieved by using MC-Lambda method, which fully exploited the known geometry constraints of the multi-antennae configuration. This method does not need to consider cycle slip problem. However, the float solution precision of integer ambiguity is low based on GPS pseudo-range and carrier phase observations, which leads to large ambiguity search space and low search efficiency. For this reason, choosing the direction cosine matrix to describe the attitude and GPS/Gyro attitude determination model was established. The float solution of integer ambiguity was calculated by matrix kalman filter algorithm, and then the fixed solution of integer ambiguity was obtained by MC-Lambda method. Simulation experimental results showed that the accuracy of float solution by Kalman filter algorithm with constraints of direction cosine matrix are improved, so the computational efficiency and the fixing success rate of the fixed integer ambiguity are all improved, particularly when GPS observations is in the bad observation condition.