利用零空间约束的GPS双差整周模糊度动态求解

On-the-Fly Ambiguity Resolution Based on Null Space Constraints of GPS Double-Differential Carrier Phase

针对非专用全球定位系统(GPS)导航型接收机,利用零空间约束动态求解GPS初始整周模糊度.对单个历元的双差载波相位观测方程进行零空间变换,避免了实时变化的三维位置参数求解;用精度衰减因子(XDOP)准则选取3个独立的双差整周模糊度,并根据GPS干涉仪测姿原理以基线长度来确定整周模糊度的搜索区间,通过基线长度约束进一步使搜索范围大大降低,模糊度最终采用多种检验方法联合确认.用Garmin25导航型单频接收机构成单基线,求解整周模糊度后在2-D平面上求解航向角,与航向参考对照后表明,采用该方法可在多个历元动态解算出整周模糊度,此时计算航姿精度可达到1°.

An efficient on-the-fly ambiguity resolution algorithm using non-dedicated GPS receivers was proposed. The double-differential carrier observation equation was transformed using null space transformation so that it need not to resolve real-time three-dimensional position parameters. The ambiguity search space was determined by short baseline length according to the principle of GPS interferometer. Three independent ambiguities are selected by XDOP to reduce the ambiguity candidates, along the baseline length constraint. The correct ambiguities was adopted by several statistical conditions aided by a low-precision heading reference. Trials were done by Garmin25 LP receivers to resolve the heading and pitch. It shows that the method can resolve the ambiguity reliably on-the-fly. The heading accuracy of the GPS attitude system can reach 1°.