[Paparazzi-devel] ins subsystem

[Gautier Hattenberger]

Hi everyone,

For people working with the master branch (development branch), after 
commit 
https://github.com/paparazzi/paparazzi/commit/6b875f40dff3a61873e343cb6472b3cc0e2b357c, 
a separated ins subsystem has been introduced for _rotorcrafts_.
This will allow to handle more easily several ins implementations.

What you need to do in your airframe file is to add this subsystem:
<subsystem name="ins"/>
With this configuration, you will have the vertical filter (float 
version) running with accelerometers and barometer, and the raw gps 
position and velocities for the horizontal part.

All airframe files in the git repository have been updated.

You can activate an horizontal filter based on gps and accelerometers by 
adding the line:
<subsystem name="ins" type="hff"/>
Please note that this code, while working, doesn't improve that much the 
estimation and should be completely re-written (anyone with an urgent 
need to do some kalman filtering ?).

You will also notice an "extended" ins subsystem, which is an attempt to 
properly use an other altitude information, like a sonar, to correct the 
barometer drift. This code is working as long as the flat earth 
assumption is correct (flying over obstacles will produce altitude step 
with a sonar) and that the input signal is not going crazy (which can be 
the case with ultrasonic sensors close to motors and propellers).

The road-map for this ins subsystem is to split the existing one into 
several, each corresponding to a given configuration (one of the 
vertical/horizontal filter or none). This should improve the readability 
of the code.

Do not hesitate to report issues.

Good flights to everyone

Gautier