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GPS Tracking Device Beats Radar Gun in Court

timothy posted more than 6 years ago | from the double-edged-sword-at-least dept.

The Courts 702

MojoKid writes "According to a release issued by Rocky Mountain Tracking, an 18-year old man, Shaun Malone, was able to successfully contest a speeding ticket in court using the data from a GPS device installed in his car. This wasn't just any old make-a-left-turn-100-feet-ahead-onto-Maple-Street GPS; this was a vehicle-tracking GPS device — the kind used by trucking fleets — or in this case, overprotective parents. The device was installed in Malone's car by his parents, and the press release makes no mention if the teenager knew that the device was installed in his vehicle at the time."

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oh yea (-1, Troll)

Anonymous Coward | more than 6 years ago | (#24237869)

trix are for kids motherfucker!!!

Heh, heh, heh. (5, Funny)

Mesa MIke (1193721) | more than 6 years ago | (#24237873)

Take that, you oppressive pigs!
We've got counter-measures.

Re:Heh, heh, heh. (5, Funny)

von_rick (944421) | more than 6 years ago | (#24237977)

All of this doesn't resonate with what I have learned in Hollywood movies. Malone should be the cops name. Its just doesn't sound right.

Re:Heh, heh, heh. (3, Funny)

Anonymous Coward | more than 6 years ago | (#24238069)

Forgot to say that his VERY OPPRESSIVE PARENTS installed the device on his car...

Re:Heh, heh, heh. (5, Funny)

Chris Burkhardt (613953) | more than 6 years ago | (#24238339)

Forgot to say that his VERY OPPRESSIVE PARENTS installed the device on his car...

Only to protect him from the cops.

mixed feelings about this (5, Insightful)

corbettw (214229) | more than 6 years ago | (#24237881)

Good thing: enabling people to install these devices voluntarily to defend themselves against false claims of speeding or reckless driving.

Bad thing: having the government mandate their installation, and at some later time mandating that the data be uploaded to a central processing facility.

Re:mixed feelings about this (4, Insightful)

CRCulver (715279) | more than 6 years ago | (#24237933)

Agreed. While some people fret about modern society approaching the dystopia of 1984 [amazon.com] , I think it's scary that technology has moved to the point where government could easily do even more to hold citizens down. Orwell didn't foresee electronic tracking devices that could follow you wherever you go. In the book, the protagonist got a break from the telescreen for a few hours by walking down to a remote place. Now, even this means of privacy isn't guaranteed.

Re:mixed feelings about this (1)

jd (1658) | more than 6 years ago | (#24238375)

This is why I am firmly convinced that society cannot develop lopsidedly - if technology is progressing rapidly, then those individuals who govern the technology should not be permitted to stagnate. As I see it, this loosely divides up into ethics (how you deal with what you have got) and artistic expression (how you deal with you dealing with what you've got). Ethics evolves by questioning old ideas that are no longer valid, no matter how cherished they may be. Expression evolves by safeguarding such expression but also by encouraging people to leave "safe" formulaic art and venture into new ground. That would give society a lot more of a voice, but also a more effective safety-valve. Change produces tensions, but tensions can be grounded.

If the development of science, technology and society was kept in a dynamic equilibrium, with whichever one is faster pulling the others to where they should be, then a 1984 scenario becomes impossible. 1984-type dystopias are only possible if one of those three prongs exceeds the ability of the other two to keep it in balance. If society exceeds science or technology by too much, society's natural fears will cripple the other two and balance becomes impossible. If science exceeds society or technology, then what you understand exceeds what you can control and paranoia results. The cult of Pythagoras is a good example. If technology is king, then what you can do exceeds what you can control or understand, and the results are often self-destructive.

Re:mixed feelings about this (1, Interesting)

iamnot (849732) | more than 6 years ago | (#24238473)

Agreed. While some people fret about modern society approaching the dystopia of 1984 [amazon.com] , I think it's scary that technology has moved to the point where government could easily do even more to hold citizens down. Orwell didn't foresee electronic tracking devices that could follow you wherever you go. In the book, the protagonist got a break from the telescreen for a few hours by walking down to a remote place. Now, even this means of privacy isn't guaranteed.

42,642 people died in 2006 in the USA from vehicle crashes. If requiring a GPS in every vehicle would help reduce this number, and also protect citizens from the occasional police harassment, why not? And for those not fond of the government knowing so much about them, do like I do - ride a bicycle to work! Of course, maybe GPSing bicycles is the future too...

Another take (5, Interesting)

Gazzonyx (982402) | more than 6 years ago | (#24238189)

Good thing: enabling people to install these devices voluntarily to defend themselves against false claims of speeding or reckless driving.

Bad thing: having the government mandate their installation, and at some later time mandating that the data be uploaded to a central processing facility.

My thoughts...

Good Thing: Everyone thinks the output of electronic devices is the truth, the whole truth, and nothing but the truth.
Bad Thing: Everyone thinks the output of electronic devices is the truth, the whole truth, and nothing but the truth.

Re:Another take (1)

grolaw (670747) | more than 6 years ago | (#24238359)

GIGO

Re:mixed feelings about this (5, Interesting)

plover (150551) | more than 6 years ago | (#24238207)

It's likely that you already have a monitoring device installed in your vehicle. Cars made in the last decade have increasingly sophisticated recording capabilities that record detailed information about the car's state at the time of an airbag deployment or a seatbelt pretensioning event. Some of the data stored includes the speed, throttle position, brake position, seat belt usage, etc., and it stores a buffer of information for 20 seconds before the crash event and five seconds after. The older Restraint Control Modules simply recorded safety equipment usage, but not operational information. The new recorders are located in the Powertrain Control Module and store a lot more about your vehicle. This information is usually downloaded by an officer on the accident scene, and is admissible as evidence in court.

Of course it's not as bad as your scenario. It's not retrieved unless there's an accident. But it can be retrieved without your approval, so if you had your foot on the gas and had no signs of brakes being applied, it'd sure come out in a courtroom if you lied about your driving.

Re:mixed feelings about this (4, Interesting)

Cathoderoytube (1088737) | more than 6 years ago | (#24238349)

In Quebec vehicle tracking GPS systems have been mandatory for years. It's mostly because the government made a deal with the car insurance people so all cars had to have the device installed as an 'anti theft' measure. It's a good example of how little it takes to force those things on people.

Re:mixed feelings about this (1)

erroneus (253617) | more than 6 years ago | (#24238439)

As an anti-theft measure, how effective has it been?

Re:mixed feelings about this (2, Funny)

grolaw (670747) | more than 6 years ago | (#24238355)

Hey, Libertarians don't follow rules, they make them up as needed!

Meanwhile, those of us lucky enough not to be hit by a speeding Libertarian exercising his/her "rights" - unconcerned about the speeds the road was engineered for - get to enjoy the benefits of the progressive fine system that creates an incentive for Libertarians to OBEY SPEED LAWS.

This message brought to you by your local municipal/traffic court.

Re:Speeds the road was engineered for (1)

zmollusc (763634) | more than 6 years ago | (#24238567)

Oddly enough, I was thinking on these lines only yesterday. I was driving down a piece of dual carriageway that was built in the early seventies for early seventies(crossply tyres, drum brakes, leaf springs) vehicles to do 70mph on. There are no side roads and no crossing points for pedestrians (indeed pedestrians, bicycles and mopeds are banned from this road which is cut into a little artificial canyon), yet modern traffic (well, the proles anyway) is limited to 40 mph.
I think we are told to OBEY SPEED LAWS that are made up as needed. As needed by some bureaucrat to 'massage' statistics.

Re:mixed feelings about this (1)

kitgerrits (1034262) | more than 6 years ago | (#24238527)

I recall a similar story with police and a GPS tracking device.
I was installed by command of the person's father, a police officer, who wanted his son behave himself.
(I believe there may have been a few tickets involved, before the unit got installed)

How he did it (-1, Troll)

Harmonious Botch (921977) | more than 6 years ago | (#24237883)

1) Get ticket
2) Reset clock on GPS device
3) Drive route again
4) Profit

Re:How he did it (5, Informative)

Mesa MIke (1193721) | more than 6 years ago | (#24237911)

If only.
GPS device gets time from GPS satellite, not user.

Re:How he did it (2, Interesting)

kauos (1168299) | more than 6 years ago | (#24237955)

what about the time being incorrectly recorded when taken by the speed camera? If the speed camera's absolute time was 1 minute slow, the guy could well have slowed down (especially if he ended up seeing the speed camera).

Re:How he did it (0)

Anonymous Coward | more than 6 years ago | (#24238005)

too bad. the cop did not keep up his part of the duty (or may be his teammates). anyways I think that the clocks are synched to the local headquarters. and if they are not, they should be.

Re:How he did it (0)

Anonymous Coward | more than 6 years ago | (#24238255)

They'd never admit that. If that were the case then every ticket written because of that speed camera would be suspect.

Re:How he did it (1)

cheater512 (783349) | more than 6 years ago | (#24238341)

Then the GPS logs would show that as well.

Re:How he did it (1)

whoever57 (658626) | more than 6 years ago | (#24238203)

GPS device gets time from GPS satellite, not user.

Maybe this kid's device does, but a few weeks ago, I went: "WTF?" when I realized that the clock on my run-of-the mill GPS system was wrong (by several minutes) and that I had to set it manually. I still don't understand why my GPS system clock is inaccurate.

Re:How he did it (1)

aca_broj_1 (1034904) | more than 6 years ago | (#24238333)

If your GPS time was off by even one second, your position would be off by about 300km -- give or take depending on satellite geometry -- there's no way to separate the two.

Re:How he did it (5, Informative)

Alsee (515537) | more than 6 years ago | (#24238543)

If your GPS time was off by even one second, your position would be off by about 300km -- give or take depending on satellite geometry -- there's no way to separate the two.

Sure there is. The GPS clock system is independent of our common business-day clock. GPS does not incorporate time zones, does not incorporate daylight savings time adjustments, does not incorporate leap years or leap days or leap seconds or anything else. It is not tied to any earth time system. The GPS network simply counts its own seconds, independent of our earthly wall-clock time conventions.

The GPS unit likely has an independent clock circuit so that you can have a clock even when you are not receiving any GPS signals. And if it is running off of satellite time, it would have to have some stored translation factor to convert the satellite time to an earth-clock time, to account for time zones and daylight savings time and other adjustments, and to account for the fact that the satellite time *does* drift out of sync with official earth time systems. In fact due to leap seconds and whatnot, GPS time has drifted 14 seconds out of sync with GMT / UTC Coordinated Universal Time.

The fact that it was even physically possible for him to manually set the clock proves that the satellite time was not being directly displayed on the clock, that there is either an independent internal clock and/or some stored translation factor to convert the GPS network's internal clock system into whatever "common local time" you want displayed on the user-clock. None of this would would be used in the GPS position calculations.

-

Re:How he did it (1)

daspriest (904701) | more than 6 years ago | (#24237913)

They don't work that way unfortunately.

Time is kept on the server side.

perhaps it was insurance motivated (5, Interesting)

ya really (1257084) | more than 6 years ago | (#24237891)

I believe insurance companies give discounts to drivers (especially young ones) for having gps tracking installed in their cars.

Not always (4, Informative)

atari2600 (545988) | more than 6 years ago | (#24238221)

Only if the drivers allow themselves to be tracked at all times and allow the data to be uploaded to a location where the insurance company can monitor the data at their own whim and fancy. You are right though - I know Progressive gives discounts for kids who have GPS trackers in their vehicles.

18 = still a kid (0)

Anonymous Coward | more than 6 years ago | (#24237895)

get off my lawn

(please type the word in this image: masters)

Damn you, technology! (5, Funny)

FlyingSquidStudios (1031284) | more than 6 years ago | (#24237901)

The highly accurate radio wave reflection system or the highly accurate satellite positioning system? One of you must be wrong! Machines can't lie?! MACHINES CAN'T LIE?!!??!!

Re:Damn you, technology! (1)

Vectronic (1221470) | more than 6 years ago | (#24237951)

Machines can't lie, but neither can people who live on a flat earth, its what they calculated as being accurate, even if their senses and programming was faulty.

The downside to this, is it probably wont be long before the police can tap-into your vehicles GPS (when they get more accurate in mainstream cars) to see if you are speeding or not, since their current systems are now inferior... then there's goes the whole male + car = love relationship...

"fuck you, hunka shit, you ratted me out, to the scrap yard with you"

Re:Damn you, technology! (1)

markov_chain (202465) | more than 6 years ago | (#24238085)

Now there's a neat project idea: create a GPS spoofing device that plugs into a GPS instead of the antenna. Loads of fun with GNU Radio and signal processing :)

Re:Damn you, technology! (1)

cheater512 (783349) | more than 6 years ago | (#24238369)

It would be exceptionally difficult because of the precision.

You need to emulate multiple satellites sending data at the speed of light, with precise timing.

Re:Damn you, technology! (4, Insightful)

TechyImmigrant (175943) | more than 6 years ago | (#24238389)

>Now there's a neat project idea: create a GPS spoofing device.

That is a standard piece of GPS test equipment. A test GPS signal source and an antenna cone to place over the GPS device. Any time and location can be spoofed.

Re:Damn you, technology! (4, Interesting)

MDMurphy (208495) | more than 6 years ago | (#24238483)

Self reporting speed is decades old. Pre-GPS commerical trucks in Japan showed the speed of te vehicle by a series of lights on the top of the truck cab. A cop could pull them over for speeding just by looking at the lights.

Tachographs in Europe record speed in commercial vehicles as well.

Re:Damn you, technology! (0)

Vectronic (1221470) | more than 6 years ago | (#24238511)

No offence, but are you fucking retarded?

Judge: So, what evidence do you have?
Officer: the lights went by... well, really quite fast.

And what does tachometers have to do with it? for starters, you dont have to give a cop your tachcard (at least not in Canada) so what can they do? They can however, get the tachcard from your employer IF your employer actually bothers to collect them to varify your logbooks and such, but thats generally way more trouble than a cop will go for unless someone was killed.

Being able to tap into GPS via the satellite or another means, such as requiring all new automobiles to have a special cop frequency radio-transmitter in the vehicles as well, so instead of a radar gun, your car just tells them 88.88 MPH in a 50MPH Zone...

Re:Damn you, technology! (4, Funny)

_Shad0w_ (127912) | more than 6 years ago | (#24238039)

Computer says no.

Re:Damn you, technology! (3, Informative)

whoever57 (658626) | more than 6 years ago | (#24238161)

Computer says no.

For those who don't understand the joke in the parent post, see Little Britain [youtube.com]

So... what was wrong with the gun? (5, Insightful)

jfengel (409917) | more than 6 years ago | (#24237905)

The article says that he was doing 62 MPH according to the radar gun. The GPS says 45. If the GPS was right, why was the gun wrong? Bad calibration? Operator error? Dyslexia?

How many other people were caught "speeding" by the same gun,and are they planning to notify any of them that they have reason to believe the gun was wrong?

Re:So... what was wrong with the gun? (5, Funny)

kauos (1168299) | more than 6 years ago | (#24237969)

After he provided his GPS data as evidence, the cops should have back tracked from the point in time where the speed camera and the GPS disagree. They know the spot in the road, they know the direction he was heading in. He's an 18yo kid so surely he was speeding somewhere within the last 5 minutes.

Re:So... what was wrong with the gun? (5, Insightful)

retchdog (1319261) | more than 6 years ago | (#24238025)

Except for a little something we call the Fifth Amendment: it wasn't the cops' GPS data, was it?

Re:So... what was wrong with the gun? (4, Insightful)

Macrat (638047) | more than 6 years ago | (#24238103)

Does that apply in the US anymore?

Re:So... what was wrong with the gun? (3, Funny)

retchdog (1319261) | more than 6 years ago | (#24238125)

Well, yeah. It's just harder to exercise what with the waterboarding and the electric shocks and the dogs and the deprivation, but you can still go ahead and try to remain silent.

Re:So... what was wrong with the gun? (4, Informative)

raehl (609729) | more than 6 years ago | (#24238113)

5th amendment doesn't protect you there. It only prevents you from incriminating yourself - it doesn't prevent evidence from your GPS being used. Especially if you introduce evidence from your GPS unit as a defense.

Re:So... what was wrong with the gun? (0)

Anonymous Coward | more than 6 years ago | (#24238227)

5th amendment doesn't protect you there. It only prevents you from incriminating yourself - it doesn't prevent evidence from your GPS being used. Especially if you introduce evidence from your GPS unit as a defense.

What if I get a GPS implanted in my body? Does the 5th Amendment protect me then?

Re:So... what was wrong with the gun? (1)

servognome (738846) | more than 6 years ago | (#24238417)

What if I get a GPS implanted in my body? Does the 5th Amendment protect me then?

Nope, they can force you to produce any evidence other than your admission of guilt (offer not valid in Cuba). Breathalyzer, blood tests, DNA, implanted GPS data.

Re:So... what was wrong with the gun? (1)

kauos (1168299) | more than 6 years ago | (#24238121)

But I assume he already provided the GPS data in order to prove that the cops radar gun data was incorrect. Or do courts just take people at their word over there in the US :)

Re:So... what was wrong with the gun? (1)

Jarjarthejedi (996957) | more than 6 years ago | (#24238059)

Well if we're going to use 'speeding at one point' as the definition of speeding then I challenge you to find anyone who drives near the speed limit who doesn't speed. Instantaneous speed is less important (and not measured by either device, mind you) than average.

Re:So... what was wrong with the gun? (2, Informative)

gardyloo (512791) | more than 6 years ago | (#24238279)

If the radar gun was indeed a Doppler radar device, then that's as close to a measurement of instantaneous speed as one can define. It doesn't need two distance measurements at different times; it needs a frequency shift over several (I'm guessing 50 - 100 for any sort of resolution) cycles of the wave. Since the period of the radar is likely something on the order of 0.05 ns, a Doppler radar gun may make its velocity determination with measuring only 1 - 10 ns, with great accuracy. That's instantaneous enough for Gov't work.

      Instantaneous speed is very important. No one cares if your average speed for an hour before an accident was 55 mph; they care if your instantaneous speed when you hit a pylon or another car was 120 mph.

Re:So... what was wrong with the gun? (2, Funny)

Anonymous Coward | more than 6 years ago | (#24238363)

I would say your instantaneous speed at any one point in time would be zero. Without references to any other oints in time it is impossible to determine speed.

Re:So... what was wrong with the gun? (5, Funny)

pintpusher (854001) | more than 6 years ago | (#24238469)

dude, take calculus.

Re:So... what was wrong with the gun? (0)

Anonymous Coward | more than 6 years ago | (#24238173)

Most states require the officers to calibrate the radar guns at the beginning of every shift and very seldom are they ever out of calibration 1mph let alone anything more so. If the GPS was accurate (how often does it record/update) odds are the officer clocked a vehicle next to his and id'd the wrong one as being the target. In busy roads this is very easy to do. Besides my GPS has told me my maximum speed on a trip was 135mph even though I never went over 70mph. Sounds like the judge couldn't rule it was right or wrong so decided to error on the side of the citizen.

Re:So... what was wrong with the gun? (0)

Anonymous Coward | more than 6 years ago | (#24238135)

maybe nothing was wrong with the gun, just the math... if the "speeder" was going up/down a hill than the distance traveled as seen by GPS would be less than the actual ground distance covered... a 20 MPH gap might not be accounted for by this... but if it was a really steep hill and depending on the error in the radar gun, a^2 + b^2 = c^2 might still apply

Re:So... what was wrong with the gun? (1)

sowth (748135) | more than 6 years ago | (#24238185)

I have been told handheld radar guns can be several percent off. The guy who told me said he was a security guard somewhere and they did tests and found radar guns were too inacurrate for them to use.

It would be nice to have a study for credible evidence... A quick search turns up this article from a site called radarbusters [radarbusters.com] .

Re:So... what was wrong with the gun? (4, Interesting)

rahvin112 (446269) | more than 6 years ago | (#24238247)

Likely operator error.

For all their bluster guns are only accurate under very specific circumstances. The dopler effect and software used in the gun assumes certain things when making it's speed "measurement", the first is that the measurement is head on, a cop shooting your speed from greater than a 5 degree angle can alter the measurement dramatically and greater than 15 degrees and you might as well just disregard whatever it reads as the error will exceed 35mph. Second most guns are calibrated for approaching traffic, if shot from behind, they are extremely inaccurate. Third, unless the gun is a laser based measurement system the gun picks out the fastest object in it's line of site and a typical gun has a 15 to 25 degree measurement window such that if there is a car anywhere near you going faster than you then that car is the one that will get measured. Cops are typically trained such that they know these limitations and abide by the requirements, that doesn't mean all do and it doesn't mean cops don't lie or that your age,sex,ethnicity,clothing and what you are driving plays a greater role in whether you get tickets than just about any other factor including how fast you drive. An 18 year old in gang attire driving a sporty car can drive by a cop going 15mph slower than a station wagon with a 45 year old guy in a suit and the 18 year old will get the ticket and the cop won't look twice at the other guy. Such is life.

Re:So... what was wrong with the gun? (5, Informative)

QuoteMstr (55051) | more than 6 years ago | (#24238313)

I'm no fan of the cops, but measuring at an angle to the direction of travel decreases the speed as perceived by the radar gun.

Another potential problem (4, Informative)

Sycraft-fu (314770) | more than 6 years ago | (#24238391)

Is new guns and their "pop" mode. Basically it is an ultrafast start and shutdown mode for the gun. The reason is, of course, RADAR detectors. They've gotten quite good. They don't necessarily need the gun to be on and transmitting to pick it up. When the gun is in standby (with it's electronics operating but not transmitting a beam) they can still be picked up. Same sort of way RADAR counterdetectors work. Even though the detector itself isn't trying to emit anything, it does anyhow (as does any superheterodyne device).

Ok, great, however you might pause to wonder about the ability to electronics operating in the 30GHz range to quickly come on and stabilise and, well, you'd be right. Guns in "pop" mode aren't accurate. In part due to the fast start, in part due to less data points, they can produce unreliable readings. The gun manufacturers say that pop mode isn't to be used as a final speed measurement, but that doesn't stop police forces from doing so anyhow.

Or it could be even more simple: The gun wasn't calibrated. Like any precision device, they need periodic recalibration. Had this been allowed to happen, it is entirely possible the gun was producing inaccurate readings.

It is a good idea for all drivers to take a little time to educate themselves about various speed measurement technologies and such. While I'd say the majority of police departments use their equipment right and the tickets are legit, they aren't always. If you get nailed with a bogus ticket, you don't necessarily need GPS to fight it. Tell the department you want the calibration records for the gun in question, find out if it was in pop mode, etc, etc. If they screwed up, let the judge know and they'll most likely drop the ticket.

Doppler at an angle (0)

Anonymous Coward | more than 6 years ago | (#24238501)

You're right that measuring speed with most radar guns at an angle gives an inaccurate measurement. However, the inaccuracy DECREASES the measured speed versus the actual vehicular speed. That is, head-on, or at 0 degrees, the gun is at its most accurate, but as the angle approaches 90 degrees, the measured speed will decrease to zero varying with the cosine of the angle.

(Now that's not completely accurate either, as most devices will not be able to get a good doppler reading long before you get to 90 degrees, but the general principle applies as one of the factors governing doppler speed measurements.)

So if an officer clocks you at 15 over the limit but tagged you at an angle, assuming all other factors radar gun and gun operator factors are insignificant, just be very, VERY glad the officer didn't clock your actual speed, as it was most certainly higher.

Re:So... what was wrong with the gun? (1)

crossmr (957846) | more than 6 years ago | (#24238545)

The first is that the measurement is head on,

Second most guns are calibrated for approaching traffic,

That is the same thing, or in reality part of the same point. You can't measure someone "head on" if they are driving away from you, as head implies the front..

Re:So... what was wrong with the gun? (0)

Anonymous Coward | more than 6 years ago | (#24238307)

GPS tracking in vehicles, such as the ones that trucking companies use to track their fleets operate on a line-of-sight mode, and are not very accurate. Obviously the kid got off on a technicality, because I personally have had to use GPS records in court, for the company I used to work for, and those "speed records" were dismissed because the GPS speed tracking does not operate in "real-time".

Re:So... what was wrong with the gun? (0)

Anonymous Coward | more than 6 years ago | (#24238399)

Most GPSes show average speed over the past few seconds and not the instantaneous speed. A Radar gun on the other hand gives instantaneous speed. There you have it.

His GPS is that accurate? (2, Interesting)

SoupIsGoodFood_42 (521389) | more than 6 years ago | (#24237909)

Perhaps he's just hard on the brakes as well as the accelerator.

Re:His GPS is that accurate? (1)

Frosty Piss (770223) | more than 6 years ago | (#24238521)

Perhaps he's just hard on the brakes as well as the accelerator.

FTA...

Dr. Heppe also pointed out that the GPS device released instantaneous data, and not data averaged over a distance

The most important point of the article (5, Insightful)

aepervius (535155) | more than 6 years ago | (#24237941)

is the so called professor revising his "expertise" so quickly and so radically. Now it would be interesting to know (or the court forcing him to say) on WHAT he based his first expertise and what new publicly available information made him change his mind, and why he did not make use of this information for the first written testimony. I get the feeling this guy is as much expert in GPS & radar gun, as my expertise in medicine forensic is (not much).

Re:The most important point of the article (4, Insightful)

_Shad0w_ (127912) | more than 6 years ago | (#24238071)

My guess is the expert's original statement was based on the assumption that the device was a run-of-the-mill GPS navigation system, which probably aren't accurate when it comes to speed and position.

Although if that hypothesis is correct it does leave one wondering why they made that assumption and didn't bother checking; it certainly reads like he then took a closer look at the device, when the finding was contested, and realized that it was a much more high end device.

Re:The most important point of the article (2, Interesting)

whoever57 (658626) | more than 6 years ago | (#24238277)

he device was a run-of-the-mill GPS navigation system which probably aren't accurate when it comes to speed and position.

It is difficult to tell how accurate run of the mill systems are -- I think they "snap" to the nearest road and I have seen my system think that I was off the road when driving at high altitude. Nevertheless, the ticket claimed he was doing 20mph over the limit and I am very confident that a run of the mill system is far more accurate than that.

Accuracy probably has more to do with traceability to some kind of calibration than real-world accuracy. I would guess that my system is typically accurate to about 20-30 feet.

Re:The most important point of the article (1)

awrowe (1110817) | more than 6 years ago | (#24238517)

I have seen my system think that I was off the road when driving at high altitude.

Your car can FLY?

Re:The most important point of the article (1)

blool (798681) | more than 6 years ago | (#24238175)

IANAL but from what I've read, most "experts" [philalawyer.net] are basically paid to say whatever the lawyers need them to say.

Re:The most important point of the article (1)

MDMurphy (208495) | more than 6 years ago | (#24238311)

Some GPS receivers determine velocity ( speed + course ) based on the differences between positions. Others ( better ones ) determine velocity based on the doppler shift in the signal from multiple satellites.

If the original assumption was that speed came from the first method, it is true that it's less reliable. Finding out that the second method is used in this case makes it a different case. Additionally, the velocity determined by doppler can he compared to the delta positions to make sure they are consistent. This only works since the two were determined independently.

The expert's mistake was making a snap judgement about the GPS receiver without examining it first.

Back in 1999 I got a speeding ticket for going 77 mph. I had a quality GPS logger in my car. I knew exactly where I was clocked so I compared the speed at various points leading up to where I slowed down as I got pulled over. My speed reported within 2 seconds from when I was hit with radar was 78 mph.
I decided to not fight that ticket.

You can never trust the client ... (4, Interesting)

vic-traill (1038742) | more than 6 years ago | (#24237965)

It's the same thing as a desktop, web client, or indeed the browser itself - the client can never be trusted.

Are the cops or the courts going to audit every GPS device or line of device code to ensure that 20 mph is *not* being deducted off what is written to the log above a certain speed?

Come to think of it, that's a great idea for OS or FSF - create code for popular GPS devices, and then produce the code for audit when you go to court contesting a ticket, while asking that the cops produce the code off of their device!!

Re:You can never trust the client ... (2, Insightful)

yotto (590067) | more than 6 years ago | (#24238143)

The GPS isn't logging the speed, or if it is it's as secondary, calculated data. I would assume (else I can't imagine this ever got him off) that they used the location data over time points. If you're here at point x at time a, and point y at time b, you were going (y-x)/(b-a) miles per hour.

Re:You can never trust the client ... (1)

vic-traill (1038742) | more than 6 years ago | (#24238225)

The GPS isn't logging the speed, or if it is it's as secondary, calculated data.

Okay - fair point. But I think the original point still obtains; how do the cops know the data is *not* being cooked (in whatever form it is being collected)? If the client controls the data collection/recording, the cops are at the mercy of the code on that device. Are they going to validate that code? How?

Re:You can never trust the client ... (1)

MDMurphy (208495) | more than 6 years ago | (#24238413)

Not necessarily, and in this case probably not. Speed can be determined independent of position. The "expert" probably made the snap judgment initially, only to be corrected later.

And with multiple points logged it's possible to validate by comparing it to the positions if the positions were independently determined.

Re:You can never trust the client ... (1)

jrl87 (669651) | more than 6 years ago | (#24238315)

That's a problem. Say you turn a corner or are on a steep incline, without more information the calculation will not be the correct speed. It will be the average velocity. Now there's nothing wrong with that, but in this case let's say the kid turned a corner and the distance between the two readings was 1300 feet. Well, then he could very well have actually traveled 1700 feet. If you just use the timestamps of these positions, you get the wrong speed and it could very well explain the discrepancy between the GPS and radar.

Re:You can never trust the client ... (1)

topham (32406) | more than 6 years ago | (#24238419)

Most GPS units I have used log speed, and it is independent of the location data; it is based on the results of a multi-step kalmin filter which takes into account such things as Doppler shift.

However, it is based on a filter which means the data is not instantaneous. It is an average over a very short period of time. (depending on the unit it could be 2 or 3 times more samples per second than what is actually recorded in the logs.).

GPS Speed readings are highly accurate if the vehicle is traveling at a relatively consistent speed and is not accelerating, or decelerating rapidly. It would be pretty damn obvious if the officer had clocked him accelerating or even rapidly decelerating and the GPS would have recorded the final numbers for that as well.

An older Gamin unit, the Garmin 12, or 12XL (or the 48) stores the information in the Unit with Location, Speed and timestamp. Short of actually physically dismantling the unit it or actually reprogramming the flash (possible, but far more of a challenge than most people can accomplish) you cannot affect the track data sufficient to screw up auditing. While you can upload track data to the unit it will not retain timestamp information on uploaded data, only on downloaded data. Data which was uploaded, then downloaded has a null timestamp.

Even when a GPS is generating Erroneous data they tend to do so in a way that makes it plainly obvious. Excessive speed by a significant factor, wildly changing results without consistency, etc. A consistent and constant drift is extremely unlikely in a moving vehicle. The rapid errors I've seen show up as significant speed and constant direction values which, except in an aircraft, are virtually impossible on the ground. And each of these has occurred only when stationary.

They tend to be caused by the last Satellite in a valid configuration moving behind an obstruction. (if you have the minimum of satellites then losing the last one which makes for a valid computation is really bad.) Most GPS units actually have a flag to indicate if they have any confidence in the data at all. (As well as a flag to indicate the level of confidence the rest of the time).

Re:You can never trust the client ... (2, Interesting)

grim-one (1312413) | more than 6 years ago | (#24238441)

The GPS isn't logging the speed, or if it is it's as secondary, calculated data. I would assume (else I can't imagine this ever got him off) that they used the location data over time points. If you're here at point x at time a, and point y at time b, you were going (y-x)/(b-a) miles per hour.

If you read the article, the expert witness (from the GPS company) states that the device gives instantaneous speeds - not averaged over a distance as you claim.

Re:You can never trust the client - Already done (5, Informative)

michaelhood (667393) | more than 6 years ago | (#24238205)

Come to think of it, that's a great idea for OS or FSF - create code for popular GPS devices, and then produce the code for audit when you go to court contesting a ticket, while asking that the cops produce the code off of their device!!

A variation of this has been done in a number of DUI/DWI cases. A number of defendants have demanded [google.com] that the source for the breathalyzer be made available for review by the defense.

In the cases I'm aware of, the manufacturer has refused to release the source as their agreement/license with the relevant law enforcement agency does not provide for this.

I believe the outcomes have ranged, but in general this has been a successful defense.

Re:You can never trust the client ... (2, Informative)

MDMurphy (208495) | more than 6 years ago | (#24238437)

Shaving 20 mph off the logged speed would never fool anyone. With a small amount of logged data you'd have positions, time and speed. If your speed is reported at 50 meters per second, the position better be different by 50 meters each second. So besides fudging the speed you'd have to fudge the time ( or positions ) as well. Your time as reported in the logged positions would have to run slow in additon to the bugus speed. If that were true, your log would not show you in the position the cop knew you were in at the time of the ticket.

Of course you could retroactively edit the entire log, but doing it in real time would ne tough.

Dot-point summary: (0)

Anonymous Coward | more than 6 years ago | (#24237979)

- Kid got speeding fine
- Parents let him in on the secret installed GPS tracker
- Kid tried the 'GPS Defense' and lost
- Kid appealed - expert witness said that particular GPS was accurate
- Kid won.
- GPS manufacture releases press release to show off how cool their kit is.

Happy day.

Your cell phone or navigator GPS still won't cut it.

Re:Dot-point summary: (2, Insightful)

Skapare (16644) | more than 6 years ago | (#24238091)

I suspect the scenario between your step 1 and step 2 went something like this:

  • Parents chew out kid for getting a speeding fine.
  • Kid insists he wasn't speeding.
  • Parents tell kid to stop lying.
  • Kid insists he's not lying.
  • Parents reveal tracker device and say they have the goods on him.
  • Kid still insists he wasn't speeding.
  • Parents check the recorded data on the GPS tracker.
  • Parents apologize to kid.

Re:Dot-point summary: (1)

Ihlosi (895663) | more than 6 years ago | (#24238431)

Parents apologize to kid.

Probably not.

So where can I get... (1, Funny)

Anonymous Coward | more than 6 years ago | (#24237985)

...a GPS device which will always produce data which shows I'm not speeding?

Re:So where can I get... (1)

Nushio (951488) | more than 6 years ago | (#24238201)

Any GPS is fine as long as you ride a bike.

Re:So where can I get... (1)

pintpusher (854001) | more than 6 years ago | (#24238487)

I've been warned for speeding on my bicycle. It happens.

in other news.... (1)

WwWonka (545303) | more than 6 years ago | (#24238003)

....rock beats scissors, and paper beats rock.

Re:in other news.... (1)

negRo_slim (636783) | more than 6 years ago | (#24238117)

Gob: Tell you what we're gonna do: "Rock Paper Scissors" for it.
Michael: No, no I'm not...
Gob: One, two, three. Paper covers rock.
Michael: It is a rock, though. Should beat everything.
Gob: There's not a lot of logic to it. It's kind of like on a boat with "Women and children first." I mean, why should they...

Problem (1, Interesting)

Anonymous Coward | more than 6 years ago | (#24238015)

Most GPS units don't take the Z axis into account; if you're going up or down a hill, the GPS will register a slower speed than your speedometer or a radar gun.

Re:Solution (0)

Anonymous Coward | more than 6 years ago | (#24238539)

Let's assume this is the case and that both devices are 100% accurate in their measure of speed, except the GPS ignores Z axis.

The radar measures you on the hypotenuse of the right triangle, and GPS measures you on the "adjacent" (i.e. horizontal) leg. Cos(x) = adj/hyp, so x = 43.5 degrees. Now take tan(43.5) = opp/adj = 0.948. That's 94.8% grade. (Hint: sqrt(62^2 - 45^2)/45 = 0.948, also -- and not by coincidence.)

Now let's be somewhat more realistic. According to http://deputy-dog.com/2007/09/18/the-steepest-streets-in-the-world/ [deputy-dog.com] , the world's steepest road is only 37% grade (canton avenue, pittsburgh, united states).

Let's assume the kid is cruising down the road. We know it's 37% grade. atan(37%) = 20.3 degrees. cos(20.3 deg) = 0.938. So if the GPS is "correct" and the horizontal speed is 45 mph, then the hypotenuse is 45/0.938 = 48.0 mph (not 62 seen by the gun). If the radar gun is correct, then he's traveling 62 on the hypotenuse, then it's 62*.938 = 58.1 mph on the horizontal (rather than 45 measured by the GPS).

Chances are that steepest street in your town is probably only 10% grade (5.7 degrees, or 0.995 adj/hyp = 0.5% difference). I seriously doubt he was driving on a street over 2% grade (1.1 degrees, or 0.9998 adj/hyp 0.02% difference).

I'm still betting that this particular GPS would report actual speed rather than "horizontal" speed.

It does NOT server to incriminate us too... (1)

Jane Q. Public (1010737) | more than 6 years ago | (#24238083)

... unless our right to not testify against ourselves is taken away, in one form or another (e.g., mandatory tracking).

And you can be sure that if something like that came to be, this would DEFINITELY no longer be the United States in which I was born. There would have to be a war first.

Even a consumer grade (5, Funny)

www.sorehands.com (142825) | more than 6 years ago | (#24238181)

I have a handheld Garmin GPS (with car mount) that specifications claim that it is within .75 knot accuracy on the speed display.

I used it to get out of a speeding ticket outside of El Paso. I said the GPS said I wwas doing 75, the cop said his radar gun said 76 and it is calibrated. I responded thatt my GPS uses government satellite signals. He let me go.
 

Overprotective? (0)

Anonymous Coward | more than 6 years ago | (#24238211)

If this guy's parents were really as overprotective as the article makes them out to be, they would have implanted the GPS into his skull, not his car.

Not being asked where you're going? (1)

v(*_*)vvvv (233078) | more than 6 years ago | (#24238253)

PRICELESS

By Neruos (2, Insightful)

Anonymous Coward | more than 6 years ago | (#24238257)

any type of non-video speed camera is not 100% accurate in a speed case and even those are not 100%.

A cop using any type of speed gun (laser, pop, etc) can almost 100% of the time, tell if a driver is speeding IF THE DRIVER is the only one in the LINE OF SIGHT. The issue with these guns is that they are CONE based and many things INCLUDING OTHER AUTOS will throw off they signal.

Most video speed cameras use a laser LINE OF SIGHT trigger, that produces a picture from a elapsed time. The picture is almost 100% accurate but not 100% accurate.

To this date, no hard factual science has proven that speed cameras have saved lives or reduces accidents.

Re:By Neruos (3, Informative)

grolaw (670747) | more than 6 years ago | (#24238421)

To this date, no hard factual science has proven that speed cameras have saved lives or reduces accidents.

Yeah, I've noticed that the Brits found no use at all for their systems - it's not like tracking down the speeders in central London has saved lives. I guess that the Lancet was just not hard or factual enough a source...http://www.thelancet.com/newlancet

Laser (2, Informative)

cloffin (568671) | more than 6 years ago | (#24238365)

Police departments routinely clock the wrong person due to the use of old fashioned radar rather than more specific laser radar. They wrongly think that because they are aiming it like a gun it is getting a specific person. It is sad that we have to go to an Orwellian extreme to fight such flawed evidence is regular Ka radar.

A cool way around... (2, Interesting)

Creepy Crawler (680178) | more than 6 years ago | (#24238407)

First we can use GPS gear to get our locale.

Instead of using some recorder, we can transmit this on the HAM bands via GPRS, and have it recorded via a local digipeter for a webserver.

We now have hard-ish logs to cook, along with federal laws backing us up, as it is illegal to transmit on a radio that you are not in the vicinity of. And since the data is real-time, you can argue that we have local logs X, and server logs based on my Federal License at Y.

Speed = Distance/Time (1, Insightful)

Anonymous Coward | more than 6 years ago | (#24238573)

The camera *and* the GPS are right. It depends over which distance, and over which time the vehicle was measured.

First 100 metres. Av speed 100km/h. ...see police. Hard on brakes.

Next 100 metres. Av. speed 50km/h.

Av speed over 200 metres, 75km/h. Speed while clocked, 100km/h.

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