Binary Protocol

(Supported model: MT3318, MT3329 and MT3339 based GPS module)


GlobalTop GPS module can output customized NMEA sentence in binary format. Binary protocol is an efficient way of transferring coordinate messages in binary numbers and can be easily processed by a low powered micro controller without the need for conversion and huge C++ string libraries.


Binary protocol is an efficient way of transferring coordinate messages from GPS module to micro controllers. Coordinates that used to require more than 20 bytes in NMEA can now be sent with only 8 bytes in binary protocol format. In addition, because of the increase in efficiency, a lower transfer rate can easily parse 10Hz messages without losing any packages.

Binary protocol is a lot more efficient when using tiny 8-bit micro controllers. This is because microcontrollers contain limited flash space, and the process of converting ASCII string into normal variables will require huge libraries and a lot of CPU calculation cycles, which may be too much to handle for these tiny controllers. With binary protocol, these simple bytes can be put directly into the variables with a few clock cycles, without the need for parsing, conversion and the huge C++ string libraries.

GlobalTop Solution:

GlobalTop can customize GPS module output sentences in binary mode when used in combination with GlobalTop “One Sentence†PGTOP format. See the table below for an example on the type of data available for data format conversion.

Original PGTOP Sentence (Gtop One Sentence Format)

$PGTOP, 064951.000,2307.1256,N,12016.4438,E, A,0.03, 165.480.03,N,0.06,K * checksum


Converted to Gtop Binary protocol format

0x04,0x24,0x03,0xEA,0x94,0x28,0x01,0x60,0x74,0xF4,0x01, 0x07,

0x2B,0x64,0xD4,0x01,0x01,0x00,0x00,0x00,0x00,0x00, 0x00,0x00,

0x50,0x4E,0X00,0X00,0X00, 0x95,0x4B,0xE9,0x0D,0x0A


1. The checksum will be calculated by X or all bytes (except for the preamble bytes and end word)



Checksum = Checksum ^ Buffer[I]



GlobalTop Binary Protocol customizations must be used in combination with GlobalTop One Sentence service. Please see “One Sentence†under software technologies for more details.