Hi folks,
New guy on the block (in Oslo Norway, to be slightly more precise), have followed with interest your discussion on the SIRF III modules and capabilities. Very interesting!
But I hope you guys can take it a step further. When you get into phase correlation stuff, you can also set up 3 GPS receivers on a platform, and measure the attitude.
Yes, yes, we do that already with tilt sensors - or do we really? If you put your model airplane through a perfect turn, you correlate the bank to the turn, and your perceived gravity vector still goes straight through the floor. There goes the otherwise so important tilt compensation for your compass…
Then you would need gyros and dead reckoning to warn you when your tilt reading is not true. But gyros have no “natural zero”, they drift, and are (most low cost units anyway) easily thrown off by vibration and jerks - you never know when to re-zero your tilt calculations.
Enter the GPS attitude correction data from a triangle of GPS antennas with a baseline of approximately 50 cm to 150 cm. Some current modules can do it, but you are set back some 15000 dollars for the dev-kit, which is the only way to get the API spec so you can start writing custom software and access information that I currently know far too little about… There’s some heavy duty mathematics to be done here also…
Since you SparkFun guys have already started making IMUs, this should be one really saucy bite for you and the enthusiast crowd on this forum. And while you’re at it, why not program the stuff to give both position and attitude at 10Hz (minimum)? I sincerely hope there are others out there also waiting for this kind of capability?
Best regards
Terje