RE: [Paparazzi-devel] Differential GPS through Paparazzi (James Maday)

[akochevar]

James,

DGPS is only going to get rid of localized atmospheric errors in the GPS system.  On the base station you survey the location, to get "truth" then as you fly you see how far your real base station position is from your survey.  This error is subtracted from the vehicles solution.  This works well, but in no way tells you how high you are off the ground(as GPS is measured from sea level).  If you want to do some terrain following, I would suggest an AGL sensor of some sort.  Even then just getting 10 hours of endurance is goign to be a feat in itself.  ScanEagle uses its DGPS for landing precision into the rope, not really for any navigation precision.

 

AJ

 

-------- Original Message --------
Subject: Re: [Paparazzi-devel] Differential GPS through Paparazzi
(James Maday)
From: <address@hidden>
Date: Tue, March 17, 2009 2:10 am
To: address@hidden


Hello James,

what would be the source for the differential signal?
Do you suppose to get it throught the uplink from
the GCS, some kind of local receiver on the AP or
some kind of network-device on the AP?

Marcus


On Tue, 17 Mar 2009 00:54:09 -0500, James Maday <address@hidden> wrote:
> Hello Paparazzi fans-
>
> I'm working with a team developing a UAV which will very soon employ the
> Paparazzi Autopilot (AP) for navigation. We have only just begun
> programming our airframe.xml, but before we get far I'm hoping to answer
> this feasibility question: is differential GPS (DGPS) usable by the
> Paprazzi
> system for altitude measurement?
>
> I've searched the mailing list and didn't find any previous talk of using
> DGPS with Paparazzi, so I figured I'd poll the audience to see if anyone
> has
> tried and can offer advice. Thank you very much!
>
> To answer my question here are some basic project details. The UAV must
> maintain 10-15 feet (roughly 3 - 4.5m) above the ground following
> predetermined waypoints for 10 hours. We have two sets of the TWOG with
> LEA_5H GPS device from PPZUAV. We are using a laptop w/ Intrepid Ubuntu
> Linux for the GCS. An example of a UAV that uses DGPS in its AP is the
> ScanEagle by Insitu/Boeing. (
> http://defense-update.com/products/s/scaneagle.htm )
>
> -James Maday
> St. Louis, MO
>


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