APRS for tracking crews on stage
Page 1 of 2 12 LastLast
Results 1 to 10 of 20

Thread: APRS for tracking crews on stage

  1. #1

    Default APRS for tracking crews on stage

    So its a system that has been around for quite some time. But I am not up to speed with the real world limitations.

    Could a APRS tracking unit be put in each car for an event and then monitored by organizers?
    (from my understanding the signals from each car would bounce off the every other car (beacon) in range until it gets to a internet connected station.)

    How many radios transmitting before everything gets plugged up with traffic? (could you have 40 or 50 radios?)

    As long as it is not used for commercial purposes its legal? (as in the organizers of the event being non-profit. CARS is non-profit but RA is for profit)

    How often can the radios be setup to transmit their position?
    Bryan L.
    Maker of those intercom adapters and "stuff"
    www.zerodegreec.ca

  2. Remove Advertisements
    SpecialStage.com
    Advertisements
     

  3. #2

    Default

    Example of a unit I am thinking of testing.

    http://www.byonics.com/mt-rtg
    Bryan L.
    Maker of those intercom adapters and "stuff"
    www.zerodegreec.ca

  4. #3
    Dramamine is for DramaQueens Morison's Avatar
    Join Date
    Dec 2001
    Location
    Calgary, Alberta.
    Posts
    4,813

    Default

    "The Micro-Trak RTG is a transmitter only, and may ocassionally send very short packets coincidentally with other transmitters."

    Looks like it won't relay data.
    Keith Morison
    Morison Communications

  5. Remove Advertisements
    SpecialStage.com
    Advertisements
     

  6. #4
    Uh Oh, UH OH, UHH OHHH!!! johnhuebbe's Avatar
    Join Date
    Dec 2004
    Location
    St. Peters, MO, US.
    Posts
    1,818

    Default

    10w or 30w?
    Behold the POWER of cheese! www.huebberally.com
    Organizer: 100aw.org & perryville.100aw.org/ | Rally Cars: 1970 VW Beetle & 1991 Subaru Legacy

  7. #5

    Default

    Open to anything.
    Bryan L.
    Maker of those intercom adapters and "stuff"
    www.zerodegreec.ca

  8. #6
    100 K right 4 MN_Rallymaster's Avatar
    Join Date
    Dec 2001
    Location
    Brooklyn Park, MN
    Posts
    298

    Default

    Most mobile trackers are not typically configured as "digi-peters" due to the fact that you can create a huge traffic crush in relatively short order.

    An Example:
    Car 1 Transmits and is able to be heard by 4 cars (2 ahead and 2 behind it)
    If each of these cars is a digi-peter, then car 1's report is repeated by 4 other radios
    Each of these 4 radios may be heard by 2-4 other radios each of which then also repeat the report of Car 1
    etc....

    Now you can control how many "layers" the repeating is done with the path of the packet, but if your goal is to use the cars to guarantee it reaches an uplink point, then the path would need to be long (Think Wide3-3 or worse)

    The generally accepted method is to limit your packet paths to something like Wide1-1 or Wide2-1 to limit the number of repeats as it is the expectation that in most areas, you should be able to hit a high-power digi within 2 hops that will then get your traffic out to the larger area, or an i-gate which will port the traffic to the APRS-IS (Internet).

    We have used APRS in several tests at our events in MN for purposes of tracking lead cars and sweep vehicles to try and cut down on some of the "housekeeping" traffic on the voice net. Typically it involves adding a second radio at Net Control to act as a receiver/digi-peter with a laptop attached and mapping software running. This gives the Net operators visibility into location of these course assets and also provides a way to repeat the traffic from a high-power antenna so it can be received by one of the local i-gates in the area. Our experience thus far has been that it is useful, but still intermittent due to the fact that it is a simplex system between the object being tracked and the Net station. There are places where the APRS packet may not get out to be received.

    This could be remedied by installing a few more mobile digi setups, but as of right now, the quantity of APRS operating HAMs is still low, so hardware and operational skills are at a premium.

    Brad
    Freedom is the lack of rally related stress.

  9. #7

    Default

    Thanks for the reply Brad. Your answer is what I feared. You would almost have to have a APRS crew to ensure that the stage(s) are covered and that the tracking of the cars is covered. This= more volunteers and worst of all, very specific trained individuals. This then is not feasible for our application.

    The search continues to find an economical (relatively) way of keeping track of cars on stages...
    Bryan L.
    Maker of those intercom adapters and "stuff"
    www.zerodegreec.ca

  10. #8
    pressing on tirelessly
    Join Date
    Nov 2002
    Location
    San Jose, CA.
    Posts
    2,225

    Default

    Kris Marciniak and I fiddled with this a couple of years ago at various events in the southwest. He built a number of inexpensive trackers to put in cars - a pelican box with an OpenTracker and an HT. I worked at it from the other side - I built several inexpensive digipeaters from 2m radios and TNC-X's. I deployed the digis at North Nevada Rally for a couple of years. They were about $200 ea, most of which was the antenna and the battery. (And I inadvertently drove up the price of certain 2m radios on Ebay for a few months.)

    You get collisions, but it's not really that much of a problem. You need to make sure people have their settings right though, so they don't transmit too often, or with too high a WIDE setting so you get useless extra repeats. And don't let the cars digipeat, for the reasons mentioned above.

    </rant on>The main reason I gave up on APRS is because I got frustrated with it. It offended my networking sensibilities. It's a really really really stupid protocol that was fine back in the 80s when it was invented, but really has no place in a modern world of auto-routing, self-repairing networks. I did build a digipeater board that plugs into a TNC-X with that uses OLSR, but it only ever got to the prototype stage.</rant off>

  11. #9

    Default

    Couple of random thoughts.
    Is the goal to pinpoint where someone is on stage, or just that they are on a particular stage? Transponders as they exist would work in terms of who is on stage or not, but not pinpoint. Basic access control. automate timing to a certain extent.

    If the goal is to pinpoint lost crews, would an avalanche beacon be usable tech? Something along the line of putting timer on it. Set it for x minutes before it broadcasts, so if you safely exit stage, you hit the reset or off button. If you are incapacitated, it starts to broadcast when the timer expires. Or it can be actively turned on if the crew capable of hitting the switch.

  12. #10

    Default

    The goal is to know where every car is at as close to real time as possible. From my days of avalanche beacons (please correct me if I am wrong or some new tech is available) they are a hide and seek kind of device that broadcasts a signal that can be tracked back to its source.
    Bryan L.
    Maker of those intercom adapters and "stuff"
    www.zerodegreec.ca

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •