Re: [Orekit Users] how to calculate iss passes

Subject: Re: [Orekit Users] how to calculate iss passes

From: Hank Grabowski <hank@applieddefense.com>

Date: Fri, 24 Feb 2017 08:32:54 -0500

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References: <sympa.1487848248.5407.670@orekit.org> <20170223132302.Horde.UY5rru6c-W4bGbOCXBkc2A1@messagerie.c-s.fr> <CAEGzASNm7xUPpYufKVAQSgxcQepasz+shKYbOZ0GK=-nubEYBg@mail.gmail.com>

You can do it but there isn't a quick built in function for that AFAIK.

On Fri, Feb 24, 2017 at 6:39 AM, Matteo <appdeveloper80@gmail.com> wrote:

Hi Luc,
thanks for your fast reply. I've used TLEPropagator and now it's all right!
I'd want to ask if there is a way to calculate also brightness
(magnitude) of ISS.
Thanks again!

Matteo

2017-02-23 13:23 GMT+01:00 MAISONOBE Luc <luc.maisonobe@c-s.fr>:
>
> appdeveloper80@gmail.com a écrit :
>
>> Hi,
>
>
> Hi Matteo,
>
>> I'm trying to calculate iss passes over Rome and I start from propagation
>> tutorial and I write this code
>> (https://gist.github.com/anonymous/fb939c0df8e6a72282eb27cc76840ac9).
>> But if I compare the rise and set date with the Heavens Above prevision
>>
>> (http://heavens-above.com/PassSummary.aspx?satid=25544&lat=41.9028&lng=12.4964&loc=Roma&alt=53&tz=CET)
>> I don't find a match:
>>
>> My code finds:
>>
>> Visibility on station1 begins at 2017-02-23T14:06:33.974
>> Visibility on station1 ends at 2017-02-23T14:12:28.528
>>
>> Heavens Above calculates:
>>
>> 23 Feb - 12:48:03 10° NNW 12:50:12 16° N
>> 12:52:20 10° NE daylight
>> 23 Feb - 14:24:14 10° NW 14:27:21 37°
>> NNE
>> 14:30:26 10° E daylight
>> 23 Feb - 16:00:50 10° WNW 16:03:44 29° SW
>> 16:06:36 10° SSE daylight
>>
>> Note that Heavens Above times are in CET timezone.
>>
>> Can you help me where my error is?
>
>
> From a quick check, I see two things.
>
> First is that you created a Keplerian orbit from mean orbital elements and
> propagated them as if they were osculating elements. You will get tens or
> perhaps hundreds of kilometer differences after some propagation time.
> As Heavens Above used TLE, you should use TLE too for propagation, so you
> use the same semantic on parameters and the same model.
>
> Second, when copying the mean anomaly (131.4349), it seems you forgot to
> convert from degrees to radians.
>
> Hope thi_s helps,
> Luc
>
>> Thanks,
>>
>> Matteo
>
>
>