transmitting gps location through repeater

[radio-man61]

does anyone know if it is possible to transmitt gps location through a generic repeater. for example the garmin rhino gmrs radio will show the user the location of each other is it possible to build a repeater that will extend the coverage of the location as well as the audio.

[Jim202]

You haven't provided much information to base an answer on. Like how are you sending the GPS
information? What mode is this GENERIC repeater using? Is CTCSS used to key the repeater?
Are you using CTCSS while trying to send the GPS information? Is the GPS information the only
information being sent over the radio, or is it also being used for voice? How do you plan to license
this repeater?

I am not familiar with the functionality Garmen Rhino radio and probably wouldn't spend much time
on it being that it is a GMRS radio.

Jim

does anyone know if it is possible to transmitt gps location through a generic repeater. for example the garmin rhino gmrs radio will show the user the location of each other is it possible to build a repeater that will extend the coverage of the location as well as the audio.

[radio-man61]

I guess i need to explain this a little more. Garmin makes a gmrs radio with a gps built into it ,so when you are talking to someone who has a similar radio, there is a screen on the radio that show a map and it will show your buddy that you are talking to. So you can see on the screen each user that you are talking with. The range is very limited cause it uses a gmrs frequency . you can use a ctss tone if you choose, but the radios have to be on the same channel with the same code to communicate with each other voice as well as location . my question is, is it possible to have a repeater that is capable of repeating the users location as well as their voice, because these radios are doing it on simplex, can it be done through a repeater. as for the license if it cannot be built then there is no use exploring how to license it, Thanks for the input

[Tom in D.C.]

Hams have been using these kinds of systems for many years. It's called APRS and it means Automated Packet Reporting System. It works and it works through repeaters. Do a Google search for APRS and you should hit a goldmine of information.

[dbusse]

Infinity also makes GPS mics that will interface to a bevy of radios. We use them for our Search and Rescue operations. The receive unit interfaces to Terrain Navigator via Team Tracker, and your location pops up on a topo map when you key down. It's the same principle as APRS that Tom mentioned above.

Dan

[Jim202]

For what it is worth, Pryme Radio Products ( www.pryme.com ) has a GPS mic. They use to have
one with a display screen, but they found it didn't survive the public safety users. They have since
gone to a non display mic.

EF Johnson also has the display mic as well as the non display mic for GPS.

So there are a number of companies that now have these available. Guess it all depends on
how you want to use it and what software your going to use.

Jim

[dbusse]

EF Johnson also has the display mic as well as the non display mic for GPS.

Jim

Infinity makes the one for Johnson... evidently a deal that they just struck together in the last several months.

See

http://www.infinitygearradios.com/product_GPSMic.htm

Dan

[MikeOxlong]

Has anybody done any experimenting with the GPS mic option for the ASTRO25 product line?

Specifically, decoding of the location packet on other ASTRO25 radios or computer based mapping system without purchasing Motorola's Fireground system.

I'm already running APRS at home and in my vehicle (Hamhud) but it would be nice to pull location based packets off a Quantar from an ASTRO25 radio and display them on the same APRS map.

I'm thinking something similar to the MIC-E system where a location packet is broadcast along with the voice transmission.

[Wowbagger]

Has anybody done any experimenting with the GPS mic option for the ASTRO25 product line?

Specifically, decoding of the location packet on other ASTRO25 radios or computer based mapping system without purchasing Motorola's Fireground system.

I'm already running APRS at home and in my vehicle (Hamhud) but it would be nice to pull location based packets off a Quantar from an ASTRO25 radio and display them on the same APRS map.

I'm thinking something similar to the MIC-E system where a location packet is broadcast along with the voice transmission.

That won't ever work. APCO-25 vocodes the voice signal. Trying to push a digital-to-analog system like the MIC-E through a vocoder gives you garbage - it's not narrowband FM where you can push an AFSK signal through it and get something the other side could decode.

The only ways you could do something like that would be
a) To have the radio software detect AFSK on the line, switch out the vocoder, decode the AFSK, infer a packet structure from it, impose that packet structure onto APCO-25 CAI PDU blocks, and send it - plus support on the APCO-25 base radio (a.k.a. repeater) to pass those packets. That would be MAJOR reworking of the radio firmware for no profit for the radio vendor.
b) Have a digital link from the mike, a standard for communications from the mike to the radio, a standard for imposing that data onto APCO-25 CAI PDU blocks, and again changes in the BR to pass it. You'd have profit in that the mikes would be proprietary to the manufacturer.
c) Build GPS into the radio, define the packets, and put the support in the BR. Same as #2.

[MikeOxlong]

I'm thinking something similar to the MIC-E system where a location packet is broadcast along with the voice transmission.

That won't ever work. APCO-25 vocodes the voice signal. Trying to push a digital-to-analog system like the MIC-E through a vocoder gives you garbage - it's not narrowband FM where you can push an AFSK signal through it and get something the other side could decode.

I actually said similar to and never implied trying to push an analog databurst through a digital repeater.

What I was actually inquiring about was a system similar to your Option B which is already available from Motorola using one of their GPS mic's and a compatible ASTRO25 radio.

Since this is an ASTRO25 radio, I wasn't sure whether location packets would be part of the APCO25 standard or something that's Motorola proprietary (which I assume they are).

Right now I'm assuming that the location packets are proprietary and can only be seen by Motorola's Fireground software package.

[xmo]

I have one of the Motorola GPS mics and I had the same questions.

How does it work? Could I use it with my P25 Quantar based repeater system?

The mic does work well. It acquires location quickly when it can see at least some of the sky. It will show your location coordinates on the radio display.

Unfortunately, it does not embed your coordinates into the P25 data and send them along with your voice transmissions as I had hoped.

The Motorola system that works with the GPS mics is large and complex.

For conventional operation your system would have to be set up for IV&D. That means a DIU connected to your Quantar, an RNC3000 connected to the DIU, a server and host running location application software.

The application must be configured to ask the radio for its location. It can also tell the radio how often to report its location.

Hopefully Motorola will consider offering a simpler solution in a future firmware release.

[radioinstl]

The Thales T-25 sends the GPS NEMA data as part of the P25 signal (using the MFID for Thales) and can be extracted for use with a mapping program such as ESRI.

There is a geolocation (GPS) standard going through TIA right now slated to be the new P25 GPS standard.

[john9912]

mototrbo also have gps capabilities and have an optional software interface mapping package. It sends data over the digital trbo signal. I did see a GPS/packet modem that plugged into a portable speaker mic jack or 16 pin moto mobile. It sent packet bursts of data to transmit position. It could be set to send at key up, unkey, at predetermined intervals like every 5 minutes, or could be polled from another station and automatically transmit a response. They were using this on the same analog frequency as the voice communications. Talk about annoying.... data bursts every few minutes. A local water utility sends data to and from water tanks and pump locations over the local gov't public works channel. The police dispatcher has to listen to this all day long, every day . Several times an hour squawk..turn pump on, squawk.... turn pump off. Separate frequency or digital communications is the way to go for something like this.