一种GPS接收机的完整自检测和故障分离技术

载波相位测量是目前GPS测量中精度最高的观测量,利用载波相位求解的DGPS(RTK)的精度很高,是目前高精度要求的主要产品,利用载波相位的主要问题就是容易出现周跳.更好地解决周跳问题就可以大幅度地提高GPS接收机的性能.运用最小二乘法解出敏感残差距阵,利用相关系数检测并确定发生周跳的卫星,然后进行排除.得出的这种快捷的自检测和故障分离技术,经过试验验证准确高效,可以大幅度的提高RTK接收机的性能.

Study on simple RAIM and fault isolation scheme

The DGPS, this very high accuracy is obtained by using carrier-phase measurements with an effective floating ambiguity technique together with real-time orbit and clock corrections generated at the ground network processing hubs. The net results of these techniques is to yield a very accurate navigation solution together with very small post-fit measurement residuals, which are typically only a few millimeters. The small residuals allow a very simply but effective RAIM (receiver autonomous integrity monitoring) and fault isolation technique to be employed. The detection of a measurement problem is relatively straightforward. Any significant measurement errors, which occur after the initial floating ambiguities have converged, can be detected simply by monitoring the post-fix root-mean-square (rms) residuals. Any time five or more measurements are available, these post-fix residuals can be computed and, because they are normally so small, a problem can be detected quickly by testing to see if they exceed a few centimeters. When six or more satellites are available, a single measurement fault can be isolated to the proper satellite by computing the correlation coefficient between the measurement residuals and the appropriate row (or column) of the sensitivity matrix,whose construction is described. The satellite with the measurement fault will exhibit a correlation approaching a value of one. A derivation of the sensitivity matrix (S matrix) and its use for this application are described.