Gtop Binary Protocol Customization Service

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.

 

 

1.      Service Description

Customization of output sentences in binary protocol format shown in the tables below.

 

2.      Requirement

Output Binary sentence has to be converted from “Gtop One Sentence Format”. See “One Sentence” software technology for more details.

 

3.      Supported Data Format Conversion

 

From: PGTOP “Gtop One Sentence Format”

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

 

Customize Data Format for NMEA protocol One Sentence               Table.1

Name

Example

Units

Desciption

UTC Time

064951.000

 

hhmmss.sss

Latitude

2307.1256

 

ddmm.mmmm

N/S Indicator

N

 

N=north or S=south

Longitude

12016.4438

 

ddmm.mmmm

E/W Indicator

E

 

E=east or W=west

Status

A

 

A=data valid or V=data not valid

Speed over Ground

0.03

Knots

 

Course over Ground

165.48

Degrees

True

Speed

0.03

Knots

Masured horizontal speed

Units

N

 

Knots

Speed

0.06

Km/hr

Measured horizontal speed

Units

K

 

Kiloneters per hour

 

 

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

 

Customize Data Format for Binary protocol                                Table.2

Name

Example

Units

Description

Preamble

0x04,0x24

 2bytes

Header, always the same

UTC Time

0x03

0xDF

0x12

0xD8

4 bytes

Hi byte

to

Low byte

UTC Time(hhmmss.sss)

The original value will be converted

Example:064951.000*(10^3)=64951000  

Latitude

0x01

0x60

0x74

0xCC

4 bytes

Hi byte

to

Low byte

Latitude (in decimal degrees)

The original value will be converted

Example:23.098572*(10^6)=23098572 

N/S Indicator

0x01

1byte

0x01=>North or 0x02 =>South

Longitude

0x07

0x2B

0x64

0xDF

4 bytes

Hi byte

to

Low byte

Longitude (in decimal degrees)

The original value will be converted

Example:120.284383*(10^6)=120284383 

E/W Indicator

0x01

1byte

0x01=>East or 0x02 =>West

Status

0x01

1byte

0x01 =>data valid or 0x02 =>data not valid

Course over ground

0x07

0x56

0xB7

0x00

4 bytes

Hi byte

to

Low byte

Course over ground(in degree)

The original value will be converted

Example:123.123456=>123.123456*1000000=123123456(degrees)

Speed over ground

0x00

0x00

0x00

0x24

4 bytes

Hi byte

to

Low byte

Ground Speed(knot/hr)

The original value will be converted

Example:0.036(knot/hr)=>0.036*1000=36

Units(Knots)

0x4E

1byte

Unit of Speed. Example:0x4E=’N’

Speed over ground

0x00

0x00

0x00

0x40

4 bytes

Hi byte

to

Low byte

Ground Speed(km/hr)

The original value will be converted

Example:0.067(km/hr)=>0.067*1000=67

Units(Kilometer)

0x4B

1byte

Unit of Speed. Example:0x4B=’K’

Checksum

0x47

1byte

Checksum. Refer to Note.1

End Word

0x0D

0x0A

2bytes

End word, always the same

Note.1

 

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


For(I=0;I<N;I++)
{
     Checksum = Checksum ^ Buffer[I]
}



Available Models

 

Gtop Binary Protocol” is supported on all GlobalTop GPS modules with MT3318 or MT3329 chipset. If you are interested in implementing this exciting technology into your device, contact us (sales@gtop-tech.com) right now for further information.