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Re: WiSP32 keps problem



Hello again Roy,

The summer heat must be getting to me...  I still don't see how you can
avoid having to change the checksum.

>From Assi's original email:
>So I took the Y2K epoch time -> 00015.218 changed the first 
>two digits to the year 99 and added 365 days to come up 
>with 99380.218 . This seems to work fine and the results
>agree with STK.

It seems to me that the object of the exercise is to take a set of current
year keps (eg epoch = 00015.218) and turn it into a pseudo-99 set of keps
(eg epoch = 99380.218).

To my mind, this will result in a markedly different checksum...  but
perhaps I'm missing something obvious.

Of course, merely editing the data once it is already in the program will
bypass any checksum issues.


I've spent about half an hour searching for some current (year 2000)
keplerian elements to play with, but to no avail.  Do you have some I can
work on?

Regards,


Chris



At 03:04 2000/01/02 +0000, you wrote:
>Hi Chris,
>
>Chris Hill wrote:
>> 
>> Hi Roy,
>> 
>> Can you please confirm that when you change the epoch year and day values,
>> you also have to change the checksum digit at the end of the line.
>
>No you do not, blanks and zeroes carry the same checksum value. 
>
>> If not, then this would suggest that WiSP doesn't perform a checksum test
>> to catch corrupt data.
>
>Not so. 
>
>> If the checksum does need changing, do you have an automated way of doing
>> this?  I have a program here which is ready to roll if you need it.
>
>Doesn't need changing.
> 
>> 73 Chris vk6kch
>> 
>> At 18:28 2000/01/01 +0000, you wrote:
>> >Hi Guys,
>> >
>> >Well after trying several different ways to get the 2000 epoch keps to
work
>> >in WiSP32, I agree with Assi Friedman that the only way it can be done is
>> >to change the epoch year/day value to 99365 plus the epoch day number from
>> >the 2000 keps.  For example NOAA-11 has an epoch year/day value of
00009 in
>> >the latest keps.  This has to be changed to 99374 (365+9) and will track
>> >accurately.  I suggest you edit the keplerian data file directly before
you
>> >use the Database Update function in WiSP.  If you edit this data with the
>> >WiSP Edit Database function be sure to leave a blank between the year and
>> >day values, such as 99 374 in the above example.  Chris has been notified.
>> >
>> >--
>> >73, Roy
>> >
>> 
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>
>-- 
>73, Roy
>
>Internet: w0sl@amsat.org
>Home Page: http://home.swbell.net/rdwelch
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>

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