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ArduPilot / MissionPlanner

Mission Planner Ground Control Station for ArduPilot (c# .net)
http://ardupilot.org/planner/
GNU General Public License v3.0
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Home altitude wrong #172

Open Habitatea opened 10 years ago

Habitatea commented 10 years ago

When I turn on the plane and GPS 3DFix the altitude on HUB and flight data map is 0 or close to 0, looks like relative alt. On flight plan tab, if I only read WP from plane and reset to loaded home coordinates, the Home alt is ok, but if I press "Home Location" to update de home position, this change to the same value than "Flight Data" tab. When I tested the gps with Terminal tab z are ok I try this with two APM with different AP (2.68 and 2.74b) those planes worked great until aprox. MP 1.2.78.

meee1 commented 10 years ago

I will fix this to show the correct ASL number

Habitatea commented 10 years ago

I tested it today and the ASL continues wrong for me on 1.2.80, thanks for your interest.

meee1 commented 10 years ago

the hud will always show agl. but the home position should show asl

Habitatea commented 10 years ago

The MP continue show me AGL on all items,I could send you a tlog? altitude

Thanks

meee1 commented 10 years ago

the mp will always show ASL, I was just fixing the home asl issue. I will look at adding back a fixed offset

Habitatea commented 10 years ago

But the ASL in the picture should be 50m, not 0.32, 0.32 look like AGL. Excuse me my bad english.

meee1 commented 10 years ago

yes it is agl. that is by design. currently there is no method of displaying asl

iskess commented 10 years ago

I would like to know how to use GND_ALT_OFFSET with a ground station barometer. Does MP have this ability? If so, how to I interface the baro sensor with MP? Could MP be designed to allow a barometric altimeter setting from a nearby airport to display an accurate ASL altitude? What flight planning with the Absolute Alt box checked, how does MP calculate the ASL without knowing the local weather altimeter setting?

meee1 commented 10 years ago

for asl display, click the set home alt button. this will make it display asl

meee1 commented 10 years ago

please look at the full parameter list for how to use GND_ALT_OFFSET, currently MP has no intergration with an external baro. however this value can be change by the user at any time from this list.

iskess commented 10 years ago

Thank you for the reply Michael. Could you tell me an example of how I calculate the GRD_ALT_OFFSET? I am familiar with using a barometric altimeter setting. Example: Standard is pressure is 29.92"Hg. If the local airfield weather is reporting a QNH of 30.92, that equates to about +100ft. So I should convert this to meters and enter it as the GRD_ALT_OFFSET? Is this how it's meant to work? It would be really convenient to have a an altimeter setting knob right near the HUD like a real airplane that could be set before each flight.