Can I use FieldOfViewDetector to compute ground station attenna access of satellite?

Orekit usage
1

Hi! I’ve been recently studying the Orekit. While I was reading the help doc,I got a question about the FieldOfViewDetector.The help doc says the FieldOfViewDetector is a finder for target entry/exit events with respect to a satellite sensor Field Of View.But what if the sensor is on a ground station.Can I use the propagation&event method to compute the ground sensor access to the satellite?

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2

Hi @AstroL, welcome.

Yes you can use this feature on ground, there is a dedicated GroundFieldOfViewDetector for that.

1 Like
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Thanks a lot!That works!
I have test both circumstances and check them with the STK results.They are all fine to me.Although the logic here is a little confused to me.Because the setup code of access computation for sat2station and satation2sat are almost the same.

	    		FieldOfView fov = new CircularFieldOfView(Vector3D.PLUS_K, FastMath.toRadians(60.), FastMath.toRadians(0));
	    			    		
	    		final FieldOfViewDetector fd = new FieldOfViewDetector(stationFrame, fov);
	    		final ElevationDetector ed = new ElevationDetector(gpsFrame).withConstantElevation(FastMath.toRadians(5.0));

FieldOfView fov = new CircularFieldOfView(Vector3D.PLUS_K, FastMath.toRadians(60.), FastMath.toRadians(0));
	    		
	    		
	    		final GroundFieldOfViewDetector gfd = new GroundFieldOfViewDetector(stationFrame, fov);
	    		
	    		final ElevationDetector ed = new ElevationDetector(gpsFrame).withConstantElevation(FastMath.toRadians(5.0));

And I have some more questions.If I have a number of stations/satellites with a number of attennas and beams, and I have to calculate the access times and angle offsets.Is the a proper event handler to compute the uplink or downlink simutannously or do I have to make a list and deal them in a loop?

4

I would suggest in this case to wrap pairs of detectors with BooleanDetector.andCombine and set up the handler in the combined detector that will be triggered when both visibility conditions are met.

5

Thank you so much for your speedy reply！
I’m sorry that I may not have expressed myself clearly. I’m going to build up the scenario and make the problem more specificlly.
Have a nice day!