The Automatic Vehicle Location (AVL) tab is used to quickly see the last few NMEA $GGA reported locations for all connected NTRIP Client devices.  The tab also controls the AVL server which is used to send these locations to other connected machines (see Note A).   The AVL server provides a way to use SNIP as the front end to feed data to general purpose tracking and dispatch applications available from other 3rd party software providers.

The AVL server allows other parties to connect to a designated TCP/IP port on the SNIP Caster.  All connected parties are sent a copy of each NMEA $GGA sentence when it arrives from each Rover device.  The $GGA sentence is preceded with details about each user, as shown below (identifying details obscured in this example to protect privacy).  A simple Latitude-Longitude-Height (LLH) format is also supported.  Various other formats are being developed at this time; we invite SNIP operators to tell us about your formatting needs in this regard.  A dated log file can also be kept of all $GGA sentences for post processing needs.

The setup and control of the server is covered in greater detail in this article.
(link to be provided on release).

## AVL data streaming will follow next.
## Format: UserName / Connection , RemoteIP:Port , NMEA $GGA Sentence <cr><lf>
## Lines starting with '##' are comments
## Formats are subject the change as new styles are added
C555015:C555015,118.8.x1x.204:51664,base-ABC,$GPGGA,184118.51,4302.5897056,N,14122.0341264,E,1,00,1.0,-32.058,M,32.058,M,0.0,*58
C555015:C555015,118.8.x1x.204:51664,base-ABC,$GPGGA,184119.51,4302.5897056,N,14122.0341264,E,1,00,1.0,-32.058,M,32.058,M,0.0,*59
C555015:C555015,118.8.x1x.204:51664,base-ABC,$GPGGA,184120.51,4302.5897056,N,14122.0341264,E,1,00,1.0,-32.058,M,32.058,M,0.0,*53
C555015:C555015,118.8.x1x.204:51664,base-ABC,$GPGGA,184121.52,4302.5897056,N,14122.0341264,E,1,00,1.0,-32.058,M,32.058,M,0.0,*51
DAN:C598537,152.16x.x5x.242:51645,MB123J4,$GPGGA,184127.00,1947.4123,N,07040.6030,W,5,15,0.8,-24.63,M,0.00,M,02,0000*5A
C555015:C555015,118.8.x1x.204:51664,base-ABC,$GPGGA,184122.52,4302.5897056,N,14122.0341264,E,1,00,1.0,-32.058,M,32.058,M,0.0,*52
Acadia_Unit2:C577301,21x.x3x.89.240:57464,Base-CMR,$GPGGA,184118.80,5001.929929,N,09919.533107,W,4,13,0.9,391.905,M,-22.170,M,,*5E
C555015:C555015,118.8.x1x.204:51664,base-ABC,$GPGGA,184123.54,4302.5897056,N,14122.0341264,E,1,00,1.0,-32.058,M,32.058,M,0.0,*55
C594897:C594897,204.11x.x13.60:44427,Base-CMR,$GPGGA,184124.40,5001.780938,N,09919.554756,W,4,13,0.9,392.107,M,-22.170,M,,*5A
test:C576869,204.11x.x13.160:49836,Base-CMR,$GPGGA,184122.80,4955.917881,N,09916.960313,W,4,13,0.9,387.487,M,-22.192,M,,*5E
C555015:C555015,118.8.x1x.204:51664,base-ABC,$GPGGA,184124.54,4302.5897056,N,14122.0341264,E,1,00,1.0,-32.058,M,32.058,M,0.0,*52
C555015:C555015,118.8.x1x.204:51664,base-ABC,$GPGGA,184125.54,4302.5897056,N,14122.0341264,E,1,00,1.0,-32.058,M,32.058,M,0.0,*53
CONTIVOLVO:C567815,75.20x.x7x.176:51132,iCG60_2677079,$GPGGA,184130.00,3307.28627238,N,08016.63236722,W,4,11,1.0,23.597,M,-32.204,M,1.0,0539*48
C600430:C600430,174.20x.x3x.198:3426,OSPA123,$GPGGA,184126,2800.00,N,09700.00,W,4,10,1,200,M,1,M,5,0*71
C555015:C555015,118.8.x1x.204:51664,base-ABC,$GPGGA,184126.56,4302.5897056,N,14122.0341264,E,1,00,1.0,-32.058,M,32.058,M,0.0,*52
DAN:C598537,152.16x.x5x.242:51645,MB123J4,$GPGGA,184132.00,1947.4123,N,07040.6030,W,5,15,0.8,-24.63,M,0.00,M,03,0000*5F
C555015:C555015,118.8.x1x.204:51664,base-ABC,$GPGGA,184127.56,4302.5897056,N,14122.0341264,E,1,00,1.0,-32.058,M,32.058,M,0.0,*53
C555015:C555015,118.8.x1x.204:51664,base-ABC,$GPGGA,184128.57,4302.5897056,N,14122.0341264,E,1,00,1.0,-32.058,M,32.058,M,0.0,*5D
C555015:C555015,118.8.x1x.204:51664,base-ABC,$GPGGA,184129.57,4302.5897056,N,14122.0341264,E,1,00,1.0,-32.058,M,32.058,M,0.0,*5C

Note A:
A complete set of all current connected users, those both with and without any NMEA $GGA sentence content can also be displayed using the Show Users button found in the Caster and Clients tab.

Helpful Hint:
If you set the checkbox Accept NMEA $GPGGA data (which is found in the Misc. Settings of the Preferences Dialog,  then the Caster Table entries will be adjusted to tell every NTRIP Client to send NMEA-183 $GGA sentences.  While not all NTRIP Clients will follow this direction, it will result in more devices sending NMEA $GGA sentences back to the Caster.

The Automatic Vehicle Location (AVL) tab is only enabled for Pro and Enterprise models of SNIP.