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ozvan wrote:

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George R Main wrote:

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ozvan wrote:

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The number of GPS locating points will make a huge difference in locating your signal. Fortunately the US has a large amount of antenna locations that are ground and satellite based. It could be that your location does not have these points.

GPS on cell phones, uses cell antennas to help acquire it's location and can "seem" to be better at locating if the above conditions exist. Though I would question whether the location at a racetrack will have the same cell phone coverage.

Sounds to me that your problem lies more with your location and availiable GPS coverage than it does with the product itself. IMHO

George, I recall your post doubting the accuracy etc of GPS some years ago and took it on board then and actually waiting until about 12 months ago to buy a logger with GPS. I was under the impression that the GPS only uses satellite signals not fixed ground antennas, am I wrong? We always get a good signal so that would not seem to be a problem. We have just tested the new firmware over two seperate days and let me say I am less than impressed. No splits, total run time only so no seperate laps, in short we basically blew two days. It is now in AIM's court and it their serve at love/40.

There are differences in the type of signal your recieving and the technology is progressing. 5hz, 10hz and 20hz GPS systems have major implications in accuracy. As do L1 and the newer L2 technology. L2 is much more accurate and utilitizes ground based beacons more readily. Though it still stands that an "inside the track" fixed ground antenna for locating is far more accurate than a GPS system that is using ground based antennas that are miles from the track. Though the expense of the ground antenna/GPS system is still very high.

The R.L.C. system claims to be the highest accuracy without a ground beacon, yet if you download their demo software and look at the lines created (using Sears Point) the line is outside the racetrack in places the car can't physically be at.

Further more, having been at a test that used a fairly high line GPS system (Intrack ground antenna), knowing the line the driver drove wasn't all that helpful, except when judging the differences between two drivers. Though I found using Lateral G, Steering, throttle, braking sensor differences more effective in gaining laptime rather than a adjustment to the line. In my mind, there isn't a perfect line (but there IS a perfectly driven line) and as long as the driver isn't way off, accuracy on their chosen line has far great implications for gaining speed than changing a line by a few feet.

So as it stands today, timing and speed seem to be the only real usable part of GPS, unless you have a lot of money to get a ground antenna. The best senario, is wheel speed and GPS speed for reasons of calculating gearing (differences of tire growth) mostly..IMHO

BTW, there has been hardly a problem with CDS's GPS working with Motec and Aim systems. CDS isn't working on a new camera to distract them from building reliable GPS.