APRS for tracking crews on stage - Page 2
Page 2 of 2 FirstFirst 12
Results 11 to 20 of 20

Thread: APRS for tracking crews on stage

  1. #11

    Default

    You are correct to the best of my knowledge. Doesn't fit with your goals. Carry on.

  2. Remove Advertisements
    SpecialStage.com
    Advertisements
     

  3. #12
    50 caution yump
    Join Date
    Jul 2008
    Location
    St. Louis, MO
    Posts
    660

    Default

    Not knowing much of anything about networking or radio things. Could an app on a smartphone take advantage of GPS and broadcast that? Granted we are sometimes in the middle of nowhere, but my GPS always seems to still work. Could just take a bunch of old cheap phones with GPS built in and do something?

    If I am talking out of my ass, carry on.
    #542 - 1991 Subaru Legacy Open Class

  4. #13

    Default

    That tech already exists via smartphones, but I think the cell technology is what will let you down in many of the remote locations that rally tends to be permitted. You'd also have to constantly power the phone, as the gps in most phones will exhaust the battery pretty quickly. I suppose you could get folks to join google latitude for those rallies in cellular coverage areas. That will triangulate from cell towers as well as use in phone gps. However, i suspect that isn't as elegant as the original poster is looking for.

  5. Remove Advertisements
    SpecialStage.com
    Advertisements
     

  6. #14
    pressing on tirelessly
    Join Date
    Nov 2002
    Location
    San Jose, CA.
    Posts
    2,225

    Default

    Actually I don't think it's the GPS that kills the battery, it's having the display on. My android seems to be able to go for a couple of days with the GPS on, but lighting up the screen will kill in a few hours. That and searching for service.

    But yeah, the problem with doing it with a smartphone is getting service.

    Bryan, what exactly are you trying to do? What's the 2m coverage like in your area? Do you have someone that can drop off digipeaters? What kind of budget are you facing? APRS *does* work for this sort of thing.

  7. #15
    pressing on tirelessly
    Join Date
    Nov 2002
    Location
    San Jose, CA.
    Posts
    2,225

    Default

    Oh, and I'd like to point out that if you build/acquire trackers, you can issue them to non-hams as long as they don't change the settings. The trackers are considered remote transmitters under your control.

    Well, here in the US anyway. Not sure about Canada, eh.

  8. #16

    Default

    Quote Originally Posted by hoche View Post
    Actually I don't think it's the GPS that kills the battery, it's having the display on. My android seems to be able to go for a couple of days with the GPS on, but lighting up the screen will kill in a few hours. That and searching for service.
    The active type gps kills the battery. It's not always working even if its active though. So if you have GPS enabled but you don't have Google Maps open, it's not actively tracking the satellites.

    Cell service is terrible. At STPR and NEFR this season, I could *barely* get texts out at service. Forget it on stage.
    Jim Perrin - #716, but no more Jeep.... - TeamHazardRally.com

  9. #17
    Put the steering wheel back on VentureCrew35's Avatar
    Join Date
    Aug 2010
    Location
    Springfield, MA
    Posts
    96

    Default



    In desert racing we use something called the IriTrack tracking system from International Racing Consultants. These trackers are mandatory in SCORE and Best In The Desert competition. The units operate via satellite and don't rely on the cellular networks, using GPS for location (collecting data every 5 seconds) and satellite phone communication to transfer the data (location and speed), which they relay to the event's IRC Control Center (and the internet) in two minute intervals. Additionally, the unit senses g forces and inclination. If it senses a high-g impact (over 5g) or a roll an alert goes off at the control center. The control center will then call the vehicle (unless it's still moving) via the IRC unit (it has a built in microphone and speaker) to ensure everyone in the vehicle is ok. They also sometimes call if the vehicle stops on course. In the open desert where the next competitor may not come along for another half hour or more and rescue is anywhere from 15 minutes to hours away this extra level of safety is definitely comforting. Unfortunately it isn't cheap, as the rental cost for one of these units is $275 per race. I don't think these would work for rally, but I think the concept is good. If there were a version with fewer bells and whistles and a rental cost below $100 (ideally $50 or less I'd say) I could see competitors going for it. Something like a Spot tracker would be great if it were possible to view all the trackers on a single map.

    EDIT: I realized I thought I remembered seeing one of these in Antoine's car at 100 Acre this year so I went back and checked my photos. Sure enough he had one mounted on the fuel cell behind Nat. No idea if they ever ran it at another event.
    Last edited by VentureCrew35; 12-09-2012 at 02:03 AM.

  10. #18
    pressing on tirelessly
    Join Date
    Nov 2002
    Location
    San Jose, CA.
    Posts
    2,225

    Default

    I looked into sat comms awhile back, and I suspect that the majority of that $275 price is just for that. Satellite bandwidth is spendy!

    The rest of it is pretty straightforward. Good GPS chips can be gotten for about $30, and a 3-axis accelerometer is only a couple of bucks. A microcontroller (PIC or ATMEGA, etc) to talk to those, check for extreme cases, and compose data messages is only about $4. The tricky part is the comms.

  11. #19
    into right 2 tightens
    Join Date
    Dec 2002
    Location
    San Diego, CA.
    Posts
    1,570

    Default

    Quote Originally Posted by hoche View Post
    I looked into sat comms awhile back, and I suspect that the majority of that $275 price is just for that. Satellite bandwidth is spendy!
    I suspect that satellite bandwidth may well be a significant part of the cost, but I am not sure it is as high a percentage of the cost as you might suspect. Stuff like vehicle ID, GPS position, heading & speed can likely be encoded into packet bursts of around 20 - 30 bytes. If you want the unit to transit very 2 mins, that's 30 packets per hour, so for a 24 hour race, just as an example, that's 24 hours * 30 packets * 30 bytes = ~ 20KB per competitor. I think the balance of the cost is the amortized cost of development of the system, amortized hardware cost of leasing the units for the race (& repairing broken or lost units), setting up & maintaining the back office servers to collect & process all the results, analyze results for each competitor to make sure they didn't deviate more than the allotted amount from the course, personnel to actively monitor system for triggered alarms e.g. high G impact detected by unit & call the competitor's vehicle to make sure they are okay, as well as trying to make a profit at the same time.

  12. #20

    Default

    I've been looking into using the CC1125 radio chip from Texas Instruments, paired with a cheap GPS module, RF amplifier and a microcontroller to create a tracking system running at a much higher update frequency than APRS. Like what has been said before, we can do so much better with modern tech in terms of receive sensitivity and bandwidth. I have started designing a prototype but haven't built it quite yet. At this point it looks like I could do a 5W 70cm transceiver with battery for maybe $160ish, and since the radio chip has a low-level interface I could built a custom protocol or try to integrate it into existing APRS systems. At this point I'm not sure if I can dump the money into it (college student) but I think it has potential to have a high enough sensitivity to still work in rally conditions. Certainly with a relay mesh system it could probably do even better than simplex.
    If anyone has any suggestions, info, or interest in this, please feel free to contact me.

Posting Permissions

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