GPS Alt in Lua script

ArduCopter
1

Hello Team,
I’m working on a script where it requires to take GPS Altitude. But I couldn’t access it. Can we add the GPS Alt or by requesting for adding the library in the script?

2

Should be accessible via gps:location(0)

1 Like
3

Hi, thank you for the reply. But I’m not getting the data properly as such it is giving data from mean sea level. Is there a way to get CTUN Altitude in Lua? As from MAV Explorer I can get CTUN Alt and Des Alt!

4

I believe the altitude you are looking for is covered under Location: Lua Scripts — Copter documentation

5

When you ask for GPS altitude, you are asking for an MSL value. The data is “properly” retrieved. But now that we know what you want…

There may be a more straightforward way to get the altitude value you’re after, but I didn’t find one. Here’s how to use the Location object to get altitude above home:

local ALT_FRAME = {
    ABSOLUTE = 0,
	ABOVE_HOME = 1,
	ABOVE_ORIGIN = 2,
    ABOVE_TERRAIN = 3
}

function update()
    cur_pos = ahrs:get_position()
	if not cur_pos then return update, 200 end
	cur_pos:change_alt_frame(ALT_FRAME.ABOVE_HOME)

	-- shows alt in meters above home in Mission Planner's Quick tab; select "MAV_ALT"
	gcs:send_named_float('ALT', cur_pos:alt() / 100)

	return update, 200
end

return update, 1000
1 Like
6

We also have ahrs:get_hagl() which may be a more elegant method to get what you want.

7

Would this work?

local hagl = terrain:height_above_terrain(true)
8

I think the terrain bindings are only valid if you are using a terrain model. I think my answers above are what the OP is after. But that’s a lot of “I think…”

9

That answered my question. I’m just starting to play with lua, so I’m just getting my head around these different bindings.