Advice on dihedral FoV construction


#1

Dear Colleagues,

I am writing to ask for advice on the definition of the axis1 and axis2 parameters from FieldOfView​(Vector3D center, Vector3D axis1, double halfAperture1, Vector3D axis2, double halfAperture2, double margin)

In my code I use (three) direction cosines for each axis with respect to the satellite body-fixed fame. However, from the results I generate I think that it is not the right setting. I tried to find the definition of the axis parameters on my own but I couldn’t. I am including my sketch of the dihedral FoV below.

Can you help?

Thank you and best regards.

Bogdan

Thank you @luc. The changes worked. I have updated the figure.


#2

In your sketch halfAperture1 and halfAperture2 are exchanged.
The angle halfAperture1 is counted “around” axis1.
So if for example you have center = X, axis1 = Y, axis2 = Z, then halfAperture1 is an angle counted around Y.
I.E if halfAperture1 is a tiny angle, the dihedra 1 will be a thin spindle-shaped strip along the (-Y,+X,+Y) half plane. The value of halfAperture1 correspond to how wide the strip is. If halfAperture1 is PI/2, then the strips
enlarges a lot up to correspond to the half sphere on the +X side.


#3

Dear @luc and Colleagues,

I have an additional question regarding the FieldOfView class. I am trying to set up a sensor placed somewhere on a spacecraft with the goal of simulating proximity operations. I defined a sensor frame as a child of the spacecraft body frame and have calculated the state vectors of other spacecraft in the sensor frame but I would like to detect when they are inside the FoV of the sensor.

In the current implementation the origin of the sensor frame, hence the center of the spherical lune of a dihedral FoV, is at the center of mass of the spacecraft. While this works well on a sensor that looks at Earth it is a less-than-desirable constraint for proximity operations.

I have tried to program a workaround using multiple intersecting FoVs but it doesn’t work well. Is there a workaround that someone has tried already?

To summarize, I am looking for a way to define a FoV with origin shifted from the center of mass of the spacecraft and use that FoV with a FieldOfViewDetector method.

Thank you and best regards.

Bogdan