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Antenna Guide for ISR and CGR with Verizon Wireless 4G LTE
Sample Application for Streaming GPS NMEA Information via IP to a Location Service
NMEA (National Marine Electronics Association) has developed a data format standard for PVT (position, velocity,
time) location-based reporting. The information is formatted as a single ascii text line, which is sent once every
reporting period. This standard has become popular for real-time location-based reporting and is also commonly used
for land-based systems.
This ISR app sends location information with timestamp in NMEA format once per second. The information is sent in a
UDP packet to an IP address and port number that are configured via two required variables. The app is triggered by
the ISR cellular interface coming up (active), and then it continuously sends the location information to the server. To
use the app, install the small tcl file, enable GPS NMEA, and enable the EEM application in the ISR configuration
(shown in a subsequent section below).
The following is an example of the data sent:
09:51:23.303475260 108.16.125.2 60646: 65 $GPRMC,134858.0,A,4006.152961,N,07507.354396,W,0.0,,180614,,,A*5A
Below is a diagram depicting a vehicle use case.
The full documentation and application are available at
https://supportforums.cisco.com/document/12239371/gps-nmea-streaming-over-udp
Considerations:
-
Existing systems integrators offer services or products to receive NMEA streams and provide mapping,
reporting and analytics. The app should allow an ISR with LTE eHWIC or 819 with LTE to work with these
products and services.
-
As the location information is acquired from GPS, a supported GPS antenna with direct line of sight to the sky
needs to be connected to the ISR.
-
If line of sight to the sky is lost, or the GPS antenna is disconnected, the ISR will continue to send location
data to the server. NMEA packets will still be received with latitude/longitude GPS coordinates of 0,0,0
(degrees, minutes, seconds
).