BooleanDetector.andCombine cannot be effective？

Orekit development
1

Hello,everyone! I’m having this problem：The following code does not take effect
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
final EventDetector sta1Visi1 =
new ElevationDetector(maxcheck, threshold, sta1Frame).
withConstantElevation(elevation).
withHandler((s, detector, increasing) → {
System.out.println(" Visibility on " +
detector.getTopocentricFrame().getName() +
(increasing ? " start " : " end ") +
s.getDate());
return increasing ? Action.CONTINUE : Action.STOP;
});
final EventDetector sta1Visi2 = new ElevationExtremumDetector(maxcheck, threshold, sta1Frame).withHandler(new VisibilityHandler());
BooleanDetector combined_detector = BooleanDetector.andCombine(sta1Visi1,sta1Visi2);
EventsLogger logger = new EventsLogger();
EventDetector logged_detector = logger.monitorDetector(combined_detector);
tlepropagator.addEventDetector(logged_detector );
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
but,The following code works correctly：
tlepropagator.addEventDetector(sta1Visi1);

2

Hello @hurricane313622,

This will trigger and event when your satellite is visible from both stations at the same time.
That may be why it doesn’t work. Maybe this never happens ?

What exactly are you trying to achieve ?

1 Like
3

Oh thank you so much, I finally get it, you’re right!
I want to get a station in and out of time, and I want to get the highest elevation angle. But I don’t know what to do.

4

I read your post and I know how to do it（https://forum.orekit.org/t/comparing-access-time-analysis-sgp4-stk-and-orekit/1417/6）.
The result is as follows, where Article (2) is not what I want, I know because withConstantLeverage (FastMath.toRadians (3.0)) is not used, but ElevationExtremumDetector does not support withConstantLeverage methods.

(1)2022-09-09T07:18:42.38290609907256Z max 287.505 azimuth 36.697 elevation

(2)2022-09-09T08:51:59.82111314602469Z max 304.052 azimuth 0.696 elevation

(3)2022-09-09T16:26:32.44075435373779Z max 61.580 azimuth 6.640 elevation

5

Hi @hurricane313622,

I’m not sure I understand exactly what you want but if you want to filter out elevation below 3° you can probably use BooleanDetector.andCombine with your ElevationExtremumDetector and an ElevationDetector.withConstantElevation(FastMath.toRadians (3.0)).

Is that what you’re looking for ?

6

Also consider the EventEnablingPredicateFilter which is better suited to events such as elevation extrema that are not usually used to define region boundaries the way elevation detector is.

7

thanks,Disturbing you.I’ll give it a try.