yes dear...... http://electronics.howstuffworks.com/gps1.htm you can only fit a gps to a UK 328 due to its bigger boot though *sic*
thanks... it confirms my previous hunch... it's only as accurate as the position it plots, which is variable depending on anything from atmospheric condition to the earths gravity in different cycles of the moon I doubt it's speed accuracy is therefore MUCH better than a 30 year old Marelli sender unit!!
you have GOT to be kidding. they are slow to react so you can't use them for accuracy while accelerating, but for something like we're discussing (accuracy of a speedo) they are near enough to SPOT ON...stop showing yourself to be so ignorant for once. i've got a feeling you didn't even read that link.
from what I read... the longer you drive the more the inaccuracy is removed... so on a trip, your speed can be reliably displayed... but for an accurate speed down the main straight at PI on your 1st lap of the day.... it ain't that reliable...
I have a few friends that own them here. They reckon the speedo accuracy is right on the money. I dont own one, so I do not know? Would certainly be better than a 30yr old Marelli sender unit one would think.
snippet from pp link... The receiver does this constantly whenever it's on, which means it is nearly as accurate as the expensive atomic clocks in the satellites. In order for the distance information to be of any use, the receiver also has to know where the satellites actually are. This isn't particularly difficult because the satellites travel in very high and predictable orbits. The GPS receiver simply stores an almanac that tells it where every satellite should be at any given time. Things like the pull of the moon and the sun do change the satellites' orbits very slightly, but the Department of Defense constantly monitors their exact positions and transmits any adjustments to all GPS receivers as part of the satellites' signals. This system works pretty well, but inaccuracies do pop up. For one thing, this method assumes the radio signals will make their way through the atmosphere at a consistent speed (the speed of light). In fact, the Earth's atmosphere slows the electromagnetic energy down somewhat, particularly as it goes through the ionosphere and troposphere. The delay varies depending on where you are on Earth, which means it's difficult to accurately factor this into the distance calculations. Problems can also occur when radio signals bounce off large objects, such as skyscrapers, giving a receiver the impression that a satellite is farther away than it actually is. On top of all that, satellites sometimes just send out bad almanac data, misreporting their own position.
you wouldn't do it down the straight at Phillip Island....you'd do it on the drive down there so you know a corrected speedo number for your car.
Wayyyyyyyyyyy over my head. That was ok. But did not mention anything about the speedo inaccuracy? If thats what you were trying to show us in that snippet?
huh? gps is simple. with a clean reading your speed will be accurate within a couple seconds, just maintain a speed for 5-10 seconds and it's fine.
don't worry about it....FFace says it can't work...so despite what we've all been thinking for all these years, if obviously doesn't.
ok... for clarification, despite what peepee says to the contrary... GPS does calculate speed from time spent between known locations (which are subject to inaccuracies), AND it cannot be relied upon for instantaneous speed readings... just averages... which get more accurate the longer you maintain an exact given speed... but yes of course... it's more accurate than a 30 year old Marelli sender unit... what isn't?
well here's a subject I reckon will be hard for you two to fight over .... anthills made facing magnetic north now how do they know it is magnetic north and not true north ? and who gave them the magvar for their location if they are using magnetic north ? and if GPS is so sh!te how come F111s use them as backup ? and btw, NOTHING is more accurate than a 30 yo Marelli sender unit which displays accurate information with the ignition turned off everytime
who said GPS was sh!te...? I know it wasn't me... Carl suggested using a radar gun for speedo comparison... and peepee said it was old fashioned and implied GPS would be a better tool... For pure accuracy of an instantaneous speedo reading... I think Carl was right in the first place, and peepee was wrong to think GPS would be better for that test.... so rather than try to be smart... why don't we all stick to the discussion point... oh, and even with my ignition off, my speedo is inaccurate. It doesn't rest at zero. and as for arguing... just look to see who starts them all....
Well I reckon a good car is a good car regardless of where it comes from. Just depends how you care for it. A UK concours car does = an Australian concours one. Patriotic perceptions are the same prejudice wherever you are, An Australian spec car in UK is the kiss of death. Funny that, they were all born in Maranello.
Pre pollution Aussie cars like Aston Martin DBs,Jags Rolls Royce/Bentley cars ect think I will stick to them over a UK car in general condition.Over the years I've seen to many Uk cars and their body problems.
who was talking about the speedo sender, not me, I was refering to my oil sender unit which is ONLY accurate when turned off, I have never seen an Italian oil sender unit accurate in any of the marques
Yes... a strange thing to understand.. however, some UK/Aussie cars are almost identical in spec (355/550) etc, while some are vastly different.. like 328 being the most extreme difference imaginable.... you need product knowledge to properly evaluate the relative worth of each market.
here's one of your super dooper Aussie cars Rob... http://www.ferrarichat.com/forum/showthread.php?t=134416
the yanks obviously control the satellites that the GPS system uses. they are able to dial in different degrees of accuracy, so its not a matter of how accurate GPS units are getting, but basically what the yanks feel like doing on any given day dads got a fair bit of experience in GPS thru 4wd-ing and so forth, and tells me that any given time, your GPS readout may be spot on, or you may be within anything up to a 100 foot radius of where it says you are...you never know 100% As for speed, the satellite tracks your exact speed at any given time and this is displayed 100% accurate on your GPS unit. The yanks have no security reason to make the speed readout innacurate. Should make sense
thanks... yes, it tracks your speed by plotting your position and timing it from the last known position... displaying a delayed speed reading, according to ash, of around 5-10 seconds... PROVIDED that it was accurate for position, speed is accurate (because it uses atomic clock timing)... but if it's 100ft off one time, and 15 ft the next... the speed will not be 100% true.... If I'm wrong, I'd appreciate a better technical explanation. Speed is a measure of time and distance... if one or other is not 100% accurate, the speed cannot be.... hence a Radar gun is better for true instantaneous speed readings... less error involved.. still some, but less.
