Hi !

I am having an issue using the FootprintOverlapDetector. For some regions I get the error :

org.orekit.errors.OrekitException: cannot compute aiming direction at singular point: latitude = … longitude = …

For example, I am using the method EllipsoidTesselator.buildSimpleZone to create the region in the following way:

var targetZone = EllipsoidTessellator.buildSimpleZone(1.0e-10,

new GeodeticPoint(Math.toRadians(30),Math.toRadians(-30),0),

new GeodeticPoint(Math.toRadians(-10),Math.toRadians(-30),0),

new GeodeticPoint(Math.toRadians(-10),Math.toRadians(20),0),

new GeodeticPoint(Math.toRadians(30),Math.toRadians(20),0));

Then I use the FootPrintOverlapDetector like this :

OneAxisEllipsoid earth = new OneAxisEllipsoid(Constants.WGS84_EARTH_EQUATORIAL_RADIUS, Constants.WGS84_EARTH_FLATTENING, FramesFactory.getITRF(IERSConventions.IERS_2010,true));

FootprintOverlapDetector detector = new FootprintOverlapDetector(fov, earth, targetZone, 80000.0).

withHandler(zoneAccessHandler).withMaxCheck(60);

This is giving me the error :

org.orekit.errors.OrekitException: cannot compute aiming direction at singular point: latitude = -9.079 longitude = 5

I really don’t understand the error since I am defining my region Counter Clock Wise as required and it’s not a region crossing th poles, so I don’t see how this can find a singular point …

Does someone have an idea ?

Thank you very much !