GPS Messages
from the Rocket
Technical Guide
June 2011
GPS Messaging Technical Guide
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Product Information
Utility Associates’ products utilize GPS sentences based on the National Marine Electronics Association’s, NMEA
0183 ASCII interface specification. This standard is fully defined in NMEA 0183, Version 2.30.
The Rocket distributes this GPS data in UDP messages that are sent to a specific IP address and port. Utility
Associates applies a device identifier to the beginning of the standard NMEA sentence. For the Rocket, the prefix
is the 11-character serial number.
The Rocket may also distribute GPS sentences to an IP address and port based on the Trimble ASCII Interface
Protocol (TAIP) Position/Velocity (PV) message. TAIP messages will be configured with a unique 4 character
alpha-numeric ID. Each alphabetic character should be upper-case. This standard is fully defined in the Sierra
Wireless TAIP Reference. GPS Messaging Technical Guide
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The NMEA RCM Message (Recommended Minimum)
The RCM sentence contains the essential gps pvt (position, velocity, time) data.
Here is an example message:
U10-353-123$GPRMC,123519,A,4807,038,N,01131,000,E,022,4,230394,003.1,W*64A
The table below lists the specific fields of the RMC message.
RMC Message Fields
U10-353-123
Rocket serial number
$GPRMC
Recommended Minimum sentence
123519UTC
Fix taken at 12:35:19 UTC
A
Status A=active or V=Void.
4807.038,N
Latitude 48 deg 07.038' N
01131.000,E
Longitude 11 deg 31.000' E
022.4
Speed over the ground in knots
084.4
Track angle in degrees True
230394
Date - 23rd of March 1994
003.1,W
Magnetic Variation
*6A
The checksum data, always begins with *
GPS Messaging Technical Guide
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The TAIP PV Message (Position/Velocity)
The PV sentence contains the essential gps pvt (position, velocity, time) data.
Here is an example message:
>RPV15714+3739438-1220384601512612;ID=1234;*7F,<
The table below lists the specific fields of the TAIP PV message.
Field
Format
Bytes
Units
Value
Sample
Sentence
Type
AA
2
N/A
PV
PV
GPS
Time-stamp
BBBBB
5
Sec
0-86399
15714
Latitude
±CCDDDDD
8
Degrees
North positive,
WGS-84
+37399438
Longitude
±EEEFFFFF
9
Degrees
East positive,
WGS-84
-12203846
Speed
GGG
3
MPH
N/A
015
Heading
HHH
3
Degrees
N/A
126
Fix Mode
I
1
N/A
0 = 2D GPS
1 = 3D GPS
2-8 = reserved
9 = no fix available
1
Age
F
1
N/A
0 = No Fix yet
1 = Old ≥ 10 sec
2 = Fresh < 10 sec
2
Vehicle ID
ID=GGGG
4
N/A
;ID =1234
Check Sum
*HH
2
N/A
;*7F
GPS Messaging Technical Guide
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