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Thread: This is a big project and i need a lot of minds to help

  1. #31
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    Heres a site that may help http://www.aeinet.com/kd6dx/index.html

  2. #32
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    [QUOTE=pimpJ]I still highly doubt that a <2ghz CPU could knock out all the proccessing we're discussing here. I think you'd have to have a server, of reasonable power, just to knock out all these calculations, then upload that to a site accessable from the car. QUOTE]


    Well, it will/would be difficult but a sub 2 ghz proc could do it all. You may need more than one machine or set up several stations as I mentioned before w/ cheap CB Radios and have them be constant beacons then you can always triangulate your position to then then figure out how to locate to coppers and then you can actively triangulate all positons real time. Expensive,yeah. Heavy on the programming, yeah. Worth it, yeah, it'd be cool.

    Another idea is that you could use known hotspots (open or encrypted) and their known gps locations as your beacons then triangulate the cops position from them.

    I think the hardest part is "seeing" where the coppers are.

  3. #33
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    [QUOTE=Crapathy]
    Quote Originally Posted by pimpJ
    I still highly doubt that a <2ghz CPU could knock out all the proccessing we're discussing here. I think you'd have to have a server, of reasonable power, just to knock out all these calculations, then upload that to a site accessable from the car. QUOTE]


    Well, it will/would be difficult but a sub 2 ghz proc could do it all. You may need more than one machine or set up several stations as I mentioned before w/ cheap CB Radios and have them be constant beacons then you can always triangulate your position to then then figure out how to locate to coppers and then you can actively triangulate all positons real time. Expensive,yeah. Heavy on the programming, yeah. Worth it, yeah, it'd be cool.

    Another idea is that you could use known hotspots (open or encrypted) and their known gps locations as your beacons then triangulate the cops position from them.

    I think the hardest part is "seeing" where the coppers are.

    CB? What the heck are you using CB for.

    And, how do you propose to use Hotspots and thier known location to triangulate the cops?

    Michael
    ...I love the French language...especially to curse with...Nom de Dieu de putain de bordel de merde de saloperies de connards d'enculés de ta mère. You see, it's like wiping your *** with silk, I love it.

  4. #34
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    I am unfamiliar with how radar detectors operate, but assuming you can wire something up to your computer than can report radar strengths then this is not as difficult as some think. Triangulation is not necessary. What you may want to do is mount your three sensors in the same area at perpendicular positions, so that way they represent x,y, and z axes ( you can actually probably do without z unless you also want to watch out for helicopters). The strengths reported by the three sensors can be used to form a vector indicating the direction of the source signal. The rest could be handled by software where you could either assume a) that the source is stationary, in which case you use the intersection of recorded vectors to pinpoint the source as you move down the road, or b) The source is moving at a relatively constant speed along a road, in which case you find the road/location that best meets this criteria.

  5. #35
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    Cool The problem lies in the repeater system

    I don't know a whole lot about police radios. But I do know that most departments use repeaters to broadcast their transmissions. The problem is that the GPS would show the location of the repeaters, and not the individual cars.

  6. #36
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    Quote Originally Posted by mainjc
    I don't know a whole lot about police radios. But I do know that most departments use repeaters to broadcast their transmissions. The problem is that the GPS would show the location of the repeaters, and not the individual cars.
    Not if you monitored the input frequency. The input frequency is the frequency that the officers transmit on, and is heard by the repeater receiver, and then restransmitted.

    Michael
    ...I love the French language...especially to curse with...Nom de Dieu de putain de bordel de merde de saloperies de connards d'enculés de ta mère. You see, it's like wiping your *** with silk, I love it.

  7. #37
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    quick thought and note

    Okay so basicly you want your car pc or carputer to triangulate the location of a cop by his radio. I have a quick question, than a responce if im correct:

    can you only triangulate a signal if it is being transmitted?

    the reason why i ask is because if your speeding and the cop is going to stop you than he will have to radio into dispatch that he is going to, or about to stop you so that he can give the dispatch his location so that if he doesnt respond than they can send back up - thus you have already been busted.

    and if you have three or four ant. on your car, and you can some how "triangulate" a cop car, than the ant. will be only as good a lowjack system, you will know in which direction the cop is in. (I think some one already said that though)

    and further note, most police agencies are not putting gps systems in there police cars just for that reason. they can already triangulate a police car either using the radio towers or by using the air cards that the cops laptop has to connect it to the mds (mobile dispatch system, tiburon company) but they can only do so in officer related emergency.

    I know alot about the interworkings because both of my parents work for orange county sherrifs office and my father is head of testing and developing new systems for police cars and dispatching.

  8. #38
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    Cost

    Everyone here has really good ideas for this, however, I just don't see this as being economical. Setting up antenae, etc is really expensive. And for what? To get out of a $100 ticket? It would be cool though. Just get a CB radio and learn the lingo to talk to truckers. 10-4 big fella' watch out for smokies!

  9. #39
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    Quote Originally Posted by Sillydipstixs18
    Okay so basicly you want your car pc or carputer to triangulate the location of a cop by his radio. I have a quick question, than a responce if im correct:

    can you only triangulate a signal if it is being transmitted?

    the reason why i ask is because if your speeding and the cop is going to stop you than he will have to radio into dispatch that he is going to, or about to stop you so that he can give the dispatch his location so that if he doesnt respond than they can send back up - thus you have already been busted.

    and if you have three or four ant. on your car, and you can some how "triangulate" a cop car, than the ant. will be only as good a lowjack system, you will know in which direction the cop is in. (I think some one already said that though)

    and further note, most police agencies are not putting gps systems in there police cars just for that reason. they can already triangulate a police car either using the radio towers or by using the air cards that the cops laptop has to connect it to the mds (mobile dispatch system, tiburon company) but they can only do so in officer related emergency.

    I know alot about the interworkings because both of my parents work for orange county sherrifs office and my father is head of testing and developing new systems for police cars and dispatching.
    True, you can only triangulate while a transmission is occuring. However, most MDT systems have a more continuous transmission rate. They automatically acknowledge receipt of messages. Generally messages are constantly being sent out to the field. Also, officers often times use thier MDT to communicate amongst themselves. The supervisor sends them messages. They run license plates regularly, and of course, they mark thier status through the MDT such as available, en route, on scene, taking lunch, etc.

    A setup on a car would only yield a direction. However, there was an idea to mount antennas on several, or at least three, locations with an eye towards triangulating them. The information (the time of the reception of the signal, and perhaps the strength) would then be sent to some sort of server, who would accept the information from all the antenna locations. This could technically be done with the car being a location. The transmission to the server would have to include the location at the time of reception of the signal (via gps) and if an array is used on the car, the direction it came from would be helpfull, but not necessary, and then the time of the reception would be sent to the receiver. All receive times would be based off a GPS receiver at the locations, or the atomic clock in ?Colorado? (each location would need a clock). The server would then calculate, based on timing and perhaps signal strength, where the transmission came from.

    Some of the problems I see if the SW involved to triangulate and then dispaly/send out the information to the field from the Server, interfacing the reciever and the timepiece to a computer at the various locations and cars, and then finding locations, and setting up receiver sites.

    And of course, the cost.

    Michael
    ...I love the French language...especially to curse with...Nom de Dieu de putain de bordel de merde de saloperies de connards d'enculés de ta mère. You see, it's like wiping your *** with silk, I love it.

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