In 2019, due to the parameter changes of GPS satellite, such as different roll circumference and date format, the lemi-417m long period magnetotelluric sounding instrument, which was normally used in the past, suddenly appeared the problem that GPS satellite could not be locked, which caused great trouble to the ongoing field work. Considering the constraints of project cycle, work area climate, road conditions and cost of funds, based on the analysis of data collection principle and binary data structure of the instrument, a set of software emergency solution for GPS lock loss is proposed and a set of software tool with high utility value is developed, which is worth to be popularized and used in the industry of deep geophysical survey.