[Paparazzi-devel] Doubt Regarding IR

[Arun Sajeevan]

Hi All,
I had a doubt regarding the working principle of the IR sensors.
With reference to the "Theory Of operation" mentioned in our Wiki pages, it is said that : the sensors typically have a 100 degree field of view and produce a 
somewhat sinusoidal voltage response relative to their angle 
orientation. as seen in the plot to the right.But we are not able to understand the plot shown.
It had  been earlier mentioned that the IR voltage is proportional to the :

• The angle of the aircraft
• The local ground/sky temperature difference

But the plot does not seem to follow this.Can someone please explain this? The link for the plot :http://paparazzi.enac.fr/wiki/Image:Ir_response_curve.gif
Thanks for your time.
Regards
Arun