Method for evaluating signal accuracy and positioning service availability of satellite navigation system

The invention provides a method for evaluating the signal accuracy and positioning service availability of a satellite navigation system. The method comprises the following steps of: downloading data of a broadcast ephemeris file and a precise ephemeris from websites of an international global positioning system (GPS) service (IGS) organization; according to description of a global navigation satellite system (GNSS) interface file, computing satellite approximate coordinates and satellite approximate clock correction by using the broadcast ephemeris file; computing satellite precise coordinates and satellite precise clock correction by using the precise ephemeris file; computing a satellite coordinate error and a satellite clock correction error per minute; computing a user range error of a grid point at the t-th moment; computing the accuracy of the user range error of the grid point, and counting the accuracy of the user range errors of global satellite navigation systems; computing a horizontal positioning