The $PRAVE Message Format

Overview

GPS tracking over-the-air position/status messages that the M7 GX transceiver and the Atlas Personal Locator may receive are sent out the serial port using Raveon’s proprietary message format called the $PRAVE message. The $PRAVE message is used to pass the tracked vehicle’s ID, location, speed, and status.  The $PRAVE message format is the default message format when the GPS transponder is configured for GPS mode 2.

Structured like a standard NMEA GPS message, the $PRAVE message contains a rich set of location and status information. The $PRAVE message is sent out the serial port of the radio, each time the radio receives a position message over-the-air.

There will be a total of 19 or 20 fields. The Odometer field is optional. If there are 19 total fields, the odometer value is not in the message. If there are 20 total fields, then the Odometer reading is present.  If you are parsing this message in software, continue parsing until you find the field with the *. If this is field 18, then there is no odometer reading. If it is field 19, then there is an odometer reading. 

Please note, the $PRAVE message is not transmitted over-the-air.  Raveon transmits over-the-air a highly compressed form of the data held in the $PRAVE message.  When an M7 GX receives this over-the-air position/status report, the received information is decompressed and the data is sent  out the serial port, in one of a number different formats. One of these formats is this $PRAVE message. Other options are the NMEA $GPWPL message and the $GPTLL message. These are covered in the user manual for the M7 GX radio transponder.

$PRAVE Message Format

The $PRAVE message is sent out the RV-M7 GX when it is configured for GPS 2 mode of operation.This mode is typically used with the RavTrack PC program, or other computer programs that can process position and status information.GPS mode 2 instructs that the output be sent at 38.4K bytes/second out the serial port.

Along with ID and position information, the $PRAVE contains a host of other status information.The length of this message may exceed he standard NMEA limit of 79 characters.Any product or software that uses this message must take this into account.

Following is a list of the fields sent in this message

Field

Usage

Comments

1

$PRAVE

Raveon Proprietary Header

2

From ID

The ID of the transponder that transmitted its position over the air. It is a hexadecimal (base 16) value.*

3

To ID

The ID that this position report was sent to. It is a hexadecimal (base 16) value.*

4

Latitude

dddmm.mmmm format. It is signed. + is north, – is south.No sign means north. Note: typically there are 4 decimal places, but as few as 0 decimal places are possible. Null field if no GPS lock.

5

Longitude

dddmm.mmmm format. It is signed. + is east, – is west.No sign means east. Note: typically there are 4 decimal places, but as few as 0 decimal places are possible. Null field if no GPS lock.

6

UTC time

The UTC time at the time the transmission was made.Hhmmss format. Null field if no GPS lock.

7

GPS Status

0=not valid position.> 0 is valid GPS.  1=GPS locked and valid position, 2=GPS locked with WAAS corrections applied

8

Num Satellites

The number of satellites in view

9

Altitude

The altitude in meters.Null field if no GPS lock.

10

Temperature

The internal temperature of the RV-M7 in degrees C. Typically this is 5-20 degrees above ambient.

11

Voltage

Input voltage to the device that sent this position.

12

IO status

A decimal number representing the binary inputs.

13

RSSI

The signal-strength of this message as measured by the receiver, in dBm. Note, if the message went through a repeater, it is the signal lever of the repeated message.

14

Speed

The speed of the device in km/hour, 0-255

15

Heading

The heading of the device 0-359 degrees.

16

Alerts

Alert codes for alerts currently indicated in the device.NULL means no alerts. Not all transponders support sending or receiving all of these alert codes.
“P” means a proximity alert.
“A”means alert.
“C” means critical alert,

“D” signifies the alert was acknowledged, set by ACK 1 command.
“N” means no motion alert,
“M” means man-down.
“T” Tamper alert or battery removed.
“I” Impact alert
“V” Vibration alert
“S” Service required

17

Spare

A spare field.May be used for UTC date in the future. Typically NULL.

18 (opt)

Odometer

The odometer reading if available. It is in kilometers and may or may not have decimal places. Most values will have are one decimal place. NULL/empty/missing if reading is not available or transponder did not send it.

18 or 19

*

The “*” NMEA end-of-message identifier.

19 of 20

Checksum

The NMEA 0183 checksum.

 *For use certain AVL solutions including RavTrack PC this field requires a decimal value.

Example Sentence:

No Odometer Value Sent:

$PRAVE,0001,0001,3308.9051,-11713.1164,195348,1,10,168,31,13.3,3,-83,0,0,,*66

This example shows a unit at 33° 8.9051 north latitude and 117° 13.1164 east longitude.It is not moving (0 speed).Its signal strength was -83dBm.Its altitude is 168 meters.

For your curiosity or testing purposes, below is a capture of vehicle 0003 driving around the Raveon office in Vista, California.

$PRAVE,0003,0001,3308.9077,-11713.1259,154656,1,8,200,24,11.6,0,-69,0,0,,*76
$PRAVE,0003,0001,3308.9082,-11713.1262,154716,2,8,199,24,11.6,0,-64,0,0,,*7C
$PRAVE,0003,0001,3308.9084,-11713.1267,154736,2,8,198,24,11.6,0,-64,0,0,,*7C
$PRAVE,0003,0001,3308.9092,-11713.1288,154756,2,9,198,24,11.6,0,-61,4,298,,*52
$PRAVE,0003,0001,3308.9225,-11713.1239,154816,2,8,195,25,11.6,0,-62,8,18,,*65
$PRAVE,0003,0001,3308.9418,-11713.1146,154836,2,9,190,26,11.6,0,-85,3,14,,*6D
$PRAVE,0003,0001,3308.9532,-11713.1314,154842,2,9,186,26,11.6,0,-96,38,294,,*65
$PRAVE,0003,0001,3308.9654,-11713.1665,154846,2,9,182,26,11.6,0,-102,61,292,,*53
$PRAVE,0003,0001,3308.8880,-11713.1500,155010,2,9,179,29,11.6,0,-86,19,40,,*5B
$PRAVE,0003,0001,3308.9120,-11713.1327,155030,2,9,183,30,11.6,0,-72,1,206,,*57
$PRAVE,0003,0001,3308.9116,-11713.1304,155050,2,9,191,31,11.6,0,-71,0,0,,*7C

The latest Tech Notes for the $PRAVE Data Format can be found here.

$PRAVE Message With Odometer Value Sent:

$PRAVE,0845,0001,3815.0856,-8537.1406,090023,2,10,173,25,14.2,0,-88,92,4,,,1595.2*71

This example shows a unit at 38° 15.0856 north latitude and -85° 37.1406 east longitude.It is moving at 92km/h. The electronic odometer reading for in the transponder of the vehicle is 1595.2km.

$PRAVE,0739,0001,3808.4727,-8538.2088,090013,2,10,200,25,13.2,0,-107,0,0,,,1143.1*7C
$PRAVE,0281,0001,3808.4750,-8538.2567,090022,1,9,199,25,13.1,0,-110,0,0,,,1934.9*41
$PRAVE,0845,0001,3815.0856,-8537.1406,090023,2,10,173,25,14.2,0,-88,92,4,,,1595.2*71$PRAVE,0314,0001,3811.5857,-8547.6362,090024,2,10,145,25,13.2,0,-88,0,0,,,1381.5*45$PRAVE,0739,0001,3808.4726,-8538.2088,090058,2,10,200,25,13.2,0,-106,0,0,,,1143.1*73$PRAVE,0281,0001,3808.4750,-8538.2568,090107,1,9,199,25,13.1,0,-111,0,0,,,1934.9*49$PRAVE,0845,0001,3815.6565,-8537.3903,090108,2,10,178,25,14.3,0,-91,90,354,,,1596.3*7C
$PRAVE,0314,0001,3811.5856,-8547.6362,090109,2,9,145,25,13.2,0,-88,0,0,,,1381.5*72$PRAVE,0739,0001,3808.4727,-8538.2088,090143,2,10,200,25,13.2,0,-107,0,0,,,1143.1*78$PRAVE,0281,0001,3808.4753,-8538.2569,090152,1,10,199,25,13.1,0,-116,0,0,,,1934.9*74$PRAVE,0845,0001,3816.2283,-8537.6356,090153,2,10,180,25,14.3,0,-103,89,326,,,1597.4*43

The latest Tech Notes for the $PRAVE Data Format can be found here.