How fast can it go, Mister?

Interesting thread on LinkedIn last week. Someone asked about using GPS in vehicle testing and it generated a fair number of responses, and one of them caught my interest.

It’s really quite amazing that after more than a decade of GPS use, for such a wide variety of applications, that misconceptions about accuracy still remain; I deal with this particular misunderstanding quite often. However, the LinkedIn discussion also contained one comment which boldly stated that “the maximum satellite frequency available will only allow for 20Hz GPS logging.” Wrong unfortunately (and gracefully retracted a couple of posts later) but it did get me questioning what the theoretical fastest log rate might be. I’m sure I used to know… or maybe not, so I checked.

GPS satellites output what’s called the Coarse Acquisition Code at 1023 Mhz, the code itself being 1023 bits long. I won’t do any more maths (you can look it up) but this then gives you a possible log rate of 1000Hz. Imagine that: one thousand samples every second to test your vehicle dynamics… I wonder when the technology will be created to produce such a sensor? I also wonder if 1000Hz logging will ever actually be necessary; but I’d like to find out.

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4 thoughts on “How fast can it go, Mister?

  1. Dennis Chalfont says:

    What is used for Bonneville trap speeds? VBOX or Photocell? I know photocell is used for drag racing.

  2. Dennis Chalfont says:

    I watched a video on Autoweek showing the Hennesy GT, readout went to tenths.

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