地球センサーとしてのGPS連続観測網の高度化

―GPS観測量に含まれるシグナルとノイズの分離―

抄録

A journey of the improvement in analysis model of the GPS Earth Observation Network System (GEONET) is reviewed along a history of GPS observation technique in the 1990s as a background. Results of the studies were applied to the analysis strategy of GEONET and the routine solutions are obtained with dramatically improved quality; high precision of coordinates, uniform quality and consistency in biases of vertical coordinates . The accomplished quality is the essential contribution to many geodetic/geophysical applications of the GEONET solutions. Insufficiency of calibration and correlation among unknown parameters are major difficulties to understand error factors of GPS. To resolve the complicated situations of problems and to get insight into "error factors", I suggest to analyze two aspects of errors: "error sources" and "compliance/sensitivity of models". Decorrelation of parameters by introduction of independent observation or tuning of analysis model is as essential as elimination/correction of error sources by calibration of observable to reduce errors in solutions. With widening and deepening of geodetic/geophysical applications, requirements for precise GPS observation are still becoming higher for more precision, higher temporal resolution, more consistency with other techniques and long-term stability . Comprehension of error factors should be a base of efforts to meet with those requirements and further exploitation of ability of GPS observation.