beansbaxter
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posted September 16, 2004 03:35 PM
Speed detection with GPS...
Ok swft, freek, and all others...
I swear this is no bs. I heard about this from a police officer in Bellevue this past June. However, I may be explaining it misinterpreting it completely wrong so please bear with me.
I was informed of GPS technology to calculate speed of motor vehicles. Just as a mobile GPS unit can be attached to a moving vehicle to use a satellite to report actual speed, so can it be used to determine if your speeding.
The pro's is that is highly accurate, with little room for error. The con's are that is slow and not a quick determination of speed compared to radar and laser methods.
He explained to me, that it is undetectable because you cant block nor detect the GPS's speed analysis, therefore companies (i.e. Escort) are working on new detectors to detect GPS use for law enforcement purposes.
I did some searching on the good ole Internet, and the only documented use I can find is in the United Kingdom it seems like. It looks like cameras that record motorists are detecting speed using GPS, and they just have GPS detectors to alert you when your entering a zone that is GPS covered. It is merely a file that is accessed while your driving to see if you enter into one of these zones. It does not scan and detect the presence of these zones in any active fashion.
Another thing that police officer said was they were having limited use/success with it in Ellensburg, WA. Whether there is any validity to that statement, I do not know.
The only other thing that is new out there, is POP technology, which I know nothing about, except places in Vegas and Reno are using it. It is one of the new things on my X50 radar detector.
May the discussion begin...
   
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TurboBlew
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posted September 16, 2004 04:02 PM
Well the cars would have to have some kinda GPS equipment installed for this to be possible.
I drove around Vegas almost 1 month ago and didnt see anything out of the ordinary as far as speed controls go.
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deathpulse
Pro
Posts: 1688
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posted September 16, 2004 04:03 PM
GPS - I doubt it. The way GPS works is that there are sats in geosync orbit that transmitt a signal .that includes a small amount of information like time etc. There are enough sats in orbit that anywhere (I think -maybe with the exception of the poles) at anytime you can pick up at least 2. These two signals... and your current possition relative to the signals give you absolute possition relative to the sats known location - hence, you can know (with a fairly high degree of accuracy) where you are. THis informaiton CAN be used to determine speed, but the speed is determined by the device in motion (several readings for location are taken over a fixed time interval - this can be calculated to determine speed). Unless the PD have a magic device (and are breaking privacy laws) that is attached to your vehicle, they have no way of using this method to determine your speed.
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deathpulse
Pro
Posts: 1688
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posted September 16, 2004 04:06 PM
BTW Beans - in addition to fancy schmancy tools like radar and lidar (active speed tracking systems)... cops CAN clock speed "old school" style. The whole term "clocking" speed comes from old school methods of using a stop watch and two known distances (utlity poles for instance) and timing you as you pass the known distance. This is a TRUE passive method to determine speed that detectors have no chance of picking up. Its a rare method these days... but I have heard tale of officers still usign it.
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beansbaxter
Needs a life
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posted September 16, 2004 04:10 PM
quote:
BTW Beans - in addition to fancy schmancy tools like radar and lidar (active speed tracking systems)... cops CAN clock speed "old school" style. The whole term "clocking" speed comes from old school methods of using a stop watch and two known distances (utlity poles for instance) and timing you as you pass the known distance. This is a TRUE passive method to determine speed that detectors have no chance of picking up. Its a rare method these days... but I have heard tale of officers still usign it.
They still do it in WA. I dont know if you read about one traffic citation I received a few months back, but there was a helicopter up in the sky who was using a stopwatch to time my bike as I passed the painted marks on the shoulder of the road. Not pretty.
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beansbaxter
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posted September 16, 2004 04:17 PM
Here are just a few random pics taken that day in Bellevue...
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ridgeracer
Pro
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posted September 16, 2004 04:27 PM
I would have to agree with deathpulse (imagine that).
The GPS system that we all know and love with sats in the sky would require that the vehicle have a GPS rcvr that the cops could query to ask it how fast the car was going. Unlikely.
I found the UK site mentioned. It does talk of using GPS to warn you of fixed location speed cameras. It has a list of their locations in memory. But the cameras themselves DO NOT use GPS as a detection method.
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worm~hole
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Posts: 10623
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posted September 16, 2004 05:45 PM
I am frreekin' surprised that the motorcop actually let you sit on his bike and play with his speed-recording unit...that kind of stuff is usually reserved for the little kiddies or the Swedish Blond SunTan Thong Team...hmmm....must be your youthful exuberance...certainly can't be your thong tan lines from your Brazilian trim 
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Bagster
Zone Head
Posts: 630
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posted September 16, 2004 08:10 PM
One day last spring a sheriff came out to the flying field where our club flies its model planes. The sheriff barracks is directly across the street from the park we fly at.
He was interested in my buddies plane, which is 50% scale.
They got talking and the deputy went back to the barracks to get some new thing that looks like binoculars only larger with some kind of box and gun handle built into it
He commenced to shoot the speed of my buddies plane in full dive (130mph)
Anyone know what that binocular thing was?
I was busy doing other things and didn't hear anything technical about it.
It did not look like your ordinary radar gun.
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deathpulse
Pro
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posted September 16, 2004 08:14 PM
Lidar. (laser).
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tuusinii
Pro
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posted September 16, 2004 09:52 PM
There has to be some misunderstunding because the GPS works like said (or almost). First it needs 3 satellites to determine Your position - two would give You 2 possible locations. But the reason why GPS gives You very accurate speed is that it dosen't use the location to calculate Your speed but it calculates Your speed from only one satellite. It is possible to calculate the frequency of the carrier and it depends of the speed Your going and it is very accurate ~1km/h and dosen't relate to GPS position error.
And about the police equipments... Here we have (but only 1 or 2) police cameras that take picture from side - like a field - and then computer calculates the time that individual cars spend between two known points and gives You speed. I'm not entirly sure if these cameras have laser detectors to calculate the distance so the system can measure the distance it needs but the laser is only needed when the system is initialized...
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lrg
Novice Class
Posts: 61
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posted September 16, 2004 11:11 PM
Damn cop bike gives me the creeps-cool cop though
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zxfingyz
Expert Class
Posts: 424
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posted September 17, 2004 07:52 AM
How about the onstar that cars come equiped with now? How does that know where you are? I don't use the onstar any more but it is still in the car. That is some scary shit when you get to thinking about it. They can tell where you are at any time but don't worry it only works when they request it to work and they wouldnt use it to profile you or violate your privacy in any way. Right?
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jonwright
Needs a job
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posted September 17, 2004 10:11 AM
OnStar is satellite based and uses cellular phone network as well.
There is also discussion on using the 'black box' (the ECU) in the cars themselves after an accident. They can then determine your speed, driver input etc. just like the airlines.
Stupid shit.
Naturally, like the Patriot Act, folks will just let the gov. do it because "*I'm* not guilty of anything."
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beansbaxter
Needs a life
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posted September 17, 2004 10:19 AM
quote:
There is also discussion on using the 'black box' (the ECU) in the cars themselves after an accident. They can then determine your speed, driver input etc. just like the airlines.
Have they done with motorcycles that you know of?
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jonwright
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posted September 17, 2004 10:21 AM
Nah - they'd do it in cars, but I'm sure cycles wouldn't be far behind if they started to do it.
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beansbaxter
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posted September 17, 2004 10:30 AM
I have heard of rental companies looking into the ECU's when you bring a car back to see if you "abused" the car albeit violated the rental contract.
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canadamaxxer
Pro
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posted September 17, 2004 12:19 PM
The module that is used in accidents to determine your speed, etc is the Airbag module (known as the SDM, DERM, etc). It collects all of the relevant data at all times and then records a "snapshot"of that data and burns it into a non erasable memory module. If you don't have airbags, there is no way (that I have ever heard of) to collect and store that data. I think the rental company comment is a bluff and I would require to see the raw data if I was ever in that position.....simply because I don't think the rental companies have the data. I have my own scan tool and I have never seen that data stored other than in the airbag module (and the only people that have access to the airbag info is the car manufacturer and the government). There is data stored when a trouble code sets (all part of the OBDII thing), but without the code setting, the data isn't stored.
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GreenGlenn
Expert Class
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posted September 17, 2004 10:04 PM
http://more.abcnews.go.com/sections/wnt/dailynews/rentalcar_010705.html
Doesn't say how they collected the data, but he damn sure got caught!
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canadamaxxer
Pro
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posted September 18, 2004 07:24 AM
Actually is does say....the rental car company installed a GPS unit. If The unit has data logging capabilities (which it obviously has) and the customer signed the contract about not speeding, and he sped....which he did, he is fucked when they download the data.
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