GPS specially the Quectel L70 commonly uses NMEA 0183 standard commands and MTK NMEA extended packet to control and configure the GPS module, the following is the structure of NMEA standard commands

$GPRMC,135926.000,A,0501.7061,N,07528.3049,W,0.05,0.00,060913_,A*7C

$GPVTG,0.00,T_{M,0.05,N,0.10,K,A*39}

$GPGGA,135926.000,0501.7061,N,07528.3049,W,1,5,1.71,2080.7,M,4.0,M_*4D

$GPGSA,A,3,01,23,32,19,13_{,,1.96,1.71,0.96*0F}

$GPGSV,4,1,15,11,67,143,21,23,60,220,34,13,56,284,31,51,52,261,33*77

$GPGSV,4,2,15,19,49,016,30,01,42,164,35,03,26,024,27,07,21,337,*7F

$GPGSV,4,3,15,20,18,193,16,27,18,028_{32,14,164,29,06,08,033,*79}

$GPGSV,4,4,15,16,07,052_28,05,28217,03,223,*4B

$GPGLL,0501.7061,N,07528.3049,W,135926.000,A,A*43

This shows that begins with $ and ends with "\n\r" has two device ID chars (e.g. GP) and three command ID chars (e.g RMC,VTG,GGA, etc.) followed by the data fields separated with comma, and finally a * indicates the end of data fields and the two bytes for the checksum.