After the GPS module is powered on, it will return data in a certain format at regular intervals. The data format is: "$information type, x, x, x, x, x, x, x, x, x, x, x, x, x", the starting character of each frame is "$", followed by the information type, followed by the positioning parameters, separated by commas. The complete data format of one frame is as follows:

　　$GPRMC, 080655.00, A, 4546.40891, N, 12639.65641, E, 1.045, 328.42, 170809,,, A*60

　　The meaning of the above frame data: the information type GPRMC indicates the recommended minimum positioning; 080655.00 indicates that the current time is 08:06:55; A indicates effective positioning; 4546.4 0891 indicates latitude; N indicates north latitude; 12639.65641 E stands for longitude; E stands for east longitude; 1.045 stands for speed, and its unit is knots (nautical miles/h); 328.42 stands for heading, which refers to the angle deviating from true north; 170809 stands for date, etc. For specific parameters, see the literature. In addition to the GPRMC information type, there is also the GPGGA information type, which includes GPS positioning information, of which the altitude parameter is in this information type, and other information types can be referred to in the literature.

　　The data information extraction and analysis in the design is completed by TI's low-power microcontroller MSP430F149. The method first judges whether it is the beginning of a frame of data by searching for the ASCII code "$", and then judges the current data by the five characters received. The received information type, after correctly identifying the information type of the frame, determines which positioning parameter the GPS module currently receives by the number of "," searched, and extracts the required positioning information from it. In this design, only the longitude, latitude, altitude, and time information in the information of GPRMC and GPGGA are parsed.

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