After the GPS module is powered on, it will return data in a certain format every certain time. The data format is: "$information type, x, x, x, x, x, x, x, x, x, x, x". The starting character of each frame is "$", followed by information type, followed by 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

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

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

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