Implementing a Star Camera
The orbit of a satellite can be computed from it’s location and velocity. What is more challenging is accurately determining its orientation. This is really important because satellites normally need to orient themselves to maximize the sunlight on their solar arrays and also point camera and other sensors in specific directions. There isn’t a lot to navigate with in space except the billions and billions of stars which is what a star camera does.
I thought it would be fun to try and implement a star camera. Let’s say we are given a picture of the night sky and need to determine which direction the camera is pointing in. To do this we need to compute a
direction vector and also an
up vector orthogonal to it so we know what the orientation of the camera is. For example, here is an image taken of Sirius, the brightest star in the sky. The un-cropped image in
1000 pixels square and the...
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