Beat speeding fines with GPS

[paegle boy]

video here http://www.youtube.com/watch?v=WSnH1fp2 ... re=related

[Damo.]

Quality reporting from ACA as usual!
I like how they initially present GPS as being completely accurate because it relies only on the satellites but Police radar is susceptible to outside influences like reflection off a fence post.
They then demonstrate the inaccuracy of GPS by driving through a CBD canyon of highrise buildings.

[paegle boy]

Quality reporting from ACA as usual! :

[CraigRat]

Cant view the vid here at work, so this might be right off on a different tangent:

Given a hand held GPS can neither be calibrated or validated AND is usually out by many meters with EVERY sample, yet the speed cameras are calibrated and certified to within .25kph or something, I would have though that a GPSr wouldn't hold up in court.

Another thing is that tracklogs can be altered and re-uploaded to most devices making it questionable from a evidence tampering point of view.

A good lawyer on the polices side would get this defence thrown out if they were competent, so be careful trying to use your GPS to get out of fines, you just might come up against someone with a clue.

[squalid]

Last time I got a fine, I thought "can't remember going down that road", so checked my GPS tracks, and Yes I did go down that road AND I was speeding!

[Coffee and Cache]

They then demonstrate the inaccuracy of GPS by driving through a CBD canyon of highrise buildings.

Something to bear in mind however, is that a GPS receiver does not rely solely on positions and time for calculation of speed (maybe not at all, but I'm not sure of that), but rather utilises the doppler effect from the sat carrier for greater accuracy. The speed figure tends to degrade differently from position fixes. Still not perfect, and subject to various errors of course, but probably better than you would expect looking at position error alone.

[Echo]

The weird thing we have found is when going through those fixed spots that tell you your speed, we have found our GPSr and car speedo to be in agreement and the camera to be out by 8km/h every time i.e if we are doing 100 according to GPSr & car, the fixed cameras tell us 92. Just another plot to get us to speed?

[Captain Terror]

Quality reporting from ACA as usual! :

What more need be said?

[Dvixen]

http://www.heraldsun.com.au/news/victor ... 1113864822

It was surprising that the ticket was withdrawn - I've been clocked going 1000+ km/h on my GPSr - on foot! Gotta love satellite errors! (I went form Melbourne to someplace in the gold coast in seconds, it was a whirlwind of a trip that I have no memory of!)

[Geodes]

http://www.heraldsun.com.au/news/victor ... 1113864822

It was surprising that the ticket was withdrawn - I've been clocked going 1000+ km/h on my GPSr - on foot! Gotta love satellite errors! (I went form Melbourne to someplace in the gold coast in seconds, it was a whirlwind of a trip that I have no memory of!)

Ah yes - it can give a (much) higher reading if it's getting bad signals, but I don't think it's very likely to read lower than your actual top speed, so - if you can satisfy them that you haven't fiddled with your track log, then there's no reason why they shouldn't accept the evidence of your GPSr

[J_&_J]

I've noticed while caching in both our vehicles (Holden Viva & Toyota Hilux) that the GPSr speed is always about 3-4 kph lower than the speedo reading on the car when travelling at roughly 110kph. I have to do a touch under 115kph in my Hilux for the GPS60 to register 110kph. I've wondered about the legal aspect of this, and which is the more accurate.

[gibbo003]

I think you would need to be very careful if you have been hand holding your GPS. We have downloaded our track log after sailing and found speeds in the track log over 200km/h. I would say that is how fast I had moved been placing the GPS down or picking it up. I din't know I could move that fast but someone did call out "do you want a beer"

[tronador]

I've noticed while caching in both our vehicles (Holden Viva & Toyota Hilux) that the GPSr speed is always about 3-4 kph lower than the speedo reading on the car when travelling at roughly 110kph. I have to do a touch under 115kph in my Hilux for the GPS60 to register 110kph. I've wondered about the legal aspect of this, and which is the more accurate.

Yes I agree. If I set my cruise control to 110km/h according to my Tom Tom, this is vastly different to what the speedometer says, which is usually close to 115-120km/h. Which one is correct??? If I see a fixed camera I usually go by the speedo not the GPS to be safe. Has any official test been done to determine whether the GPS is actually more accurate than the speedo/

[The SBI]

my gps has been known to record me walking well over the speed of sound, and I even went into orbit once.

[GJMMelb]

My car GPS has been sitting completely still on the desk next to the PC waiting to have caches loaded to it and all of a sudden I was supposedly driving along at about 30kmh into the next suburb (the border isnt that far from us lol) That first time it kept going for at least 10 seconds! Bizarre - unfortunately by the time I ran off to get my camera and got back it had stopped It has happened about 3 times now !! (but for a shorter time)
GJMMelb