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RACELOGIC Support Centre

VB3iS - RS232 / NMEA Output

The RS232 output is present to provide a connection to a computer for configuring the settings of the VB3iS through VBOX Setup software. It also can output NMEA format messages.

RS232 Racelogic Data Format

Protocol:

115200 Baud, no parity, 8 data bits, 1 stop bit
 

Message format:

$VB3is$glbtttaaaaoooovvvhhAAAVVVspprrHHPPRRyyxxYYzzddTTTkkqQQT1T1wwwWWWiicc
 

Parameter Number of bytes Description

$VB3is$

7

Header

g

1

GPS sats

Number of GPS satellites used

l

1

GLONASS sats

Number of GLONASS satellites used

b

1

BeiDou sats

Number of BeiDou satellites used

ttt

(MSB first)

Time

Ticks since midnight UTC, incrementing every 10 ms

aaaa

4 (MSB first)

Latitude

Signed integers, 0.0000001° per bit

oooo

4 (MSB first)

Longitude

Signed integers, 0.0000001° per bit

vvv

3 (MSB first)

Velocity

0.001 km/h per bit

hh

2 (MSB first)

Heading

0.01° per bit

AAA

3 (MSB first)

Altitude

0.01 m per bit

VVV

3 (MSB first)

Vertical velocity

0.001 m/s per bit

s

1

Solution type

pp

2 (MSB first)

Pitch angle derived from KF

0.01° per bit

rr

2 (MSB first)

Roll angle derived from KF

0.01° per bit

HH

2 (MSB first)

Heading derived from KF

0.01° per bit

PP

 

2 (MSB first)

Pitch rate derived from internal/external IMU

0.01°/sec per bit

RR

 

2 (MSB first)

Roll rate derived from internal/external IMU

0.01°/sec per bit

yy

2 (MSB first)

Yaw rate derived from internal/external IMU

0.01°/sec per bit

xx

2 (MSB first)

X accel from internal/external IMU

0.01 m/s² per bit

YY

2 (MSB first)

Y accel from internal/external IMU

0.01 m/s² per bit

zz

2 (MSB first)

Z accel from internal/external IMU

0.01 m/s² per bit

dd

2 (MSB first)

Date

DOS format

TTT

3 (MSB first)

Trigger event time

0.000001 ms per bit

kk

2 (MSB first)

Kalman Filter Status

q

1

Position Quality

QQ

2 (MSB first)

Speed Quality

0.001 m/s per bit

T1T1

2 (MSB first)

T1

0.0000001 ms per bit

www

3 (MSB first)

Wheel speed 1

0.001 m/s per bit

WWW

3 (MSB first)

Wheel speed 2

0.001 m/s per bit

ii

2 (MSB first)

Heading_IMU2 derived from KF

0.01° per bit

cc

2 (MSB first)

Checksum

See CRC Calculation example below

 

CRC Calculation example:

s[n] is a string containing the message

Polynomial:= 4129

CRC:=0;

for Loop:=1 to Length(s) do

begin

Temp:=s[Loop];

CRC:= CRC xor (integer(Temp) *256);

CRC:= CRC mod 65536;

for i:=7 downto 0 do

begin

if ( (CRC and 32768)=32768) then

begin

CRC:= CRC *2 ;

CRC:= CRC xor Polynomial;

end

else

begin

CRC:= CRC *2 ;

end;

CRC:=CRC mod 65536;

end;

end;

result:=CRC;

NMEA Output (RLS)

The VBSS can output 6 types of NMEA messages, the contents of RLS are shown below.
 

$PTPSR,RLS,V,hhmmss.ss,IMUheading,IMUpitch,IMUroll,IMU3Dquality*cs
 

Name ASCII String Units Description
Format Example
$PTPSR string $PTPSR   Message ID  
RLS string RLS   Sentence formatter  
V character V   Whether the UTC time is valid V=valid or N=not valid
hhmmss.ss hhmmss.ss 114105.00   UTC Time Current time
IMUheading string 157.531 Degrees Heading angle of IMU  
IMUpitch string 002.473 Degrees Pitch angle of IMU  
IMUroll string -02.635 Degrees Roll angle of IMU  
IMU3Dquality string 000.192   3D quality of IMU  
cs hexadecimal *5F   Checksum  
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