Re: [Paparazzi-devel] distance measurement for landing.

[antoine drouin]

ola

On Tue, Nov 10, 2009 at 8:26 AM, gisela.noci
<address@hidden> wrote:
> What 'Baro' sensor?

freescale MPX6115

> The maths does not lie.
>  [...]
> limited. This is often done, since most of our applications do not go to
> 10,000meters,(I suspect this is what they have done in the sensor in the
> quadrotor) .....

 yep, x100 gain amplifier with variable offset driven by the lpc DAC

> But, there is no free lunch here - you have to use
> amplifiers that have very low input and output noise, very low DC offset,
> and good temp stability. If you have access to a high accuracy pressure
> calibration system, you could put the sensor pack in the environmental
> chamber, and cycle the temp from 0 to whatever, and vary the pressure to the
> sensor at each temp, and generate a calibration curve to eliminate all the
> errors,ie, temp, offset, drift, etc but the cost.....(takes many hours to
> do)
>

no doubt about drift. I don't have experience with baros on fixed
wings, but I fear that the static pressure intake would need to be
quite perfect to achieve that kind of accuracy.

Regards

Poine