[amsat-bb] Re: Malaysian airliner puzzle

[Tom Busch]

Looks like I'm wrong.  The "Steering" info wasn't from CNN.  It's from this
Huffington Post article:
http://www.huffingtonpost.com/2014/03/16/malaysia-airlines-takeover_n_4972889.html.
I still would like to know how the satellite knows.

It also says that these "pings" occur every hour, so I suppose it could
have kept flying for an hour after the last contact.
Tom  WB8WOR

On Mon, Mar 17, 2014 at 11:28 AM, Tom Busch <tom at bloomington.com> wrote:

> The news has been reporting that they are using the angle of the last
> known ping from the ACARS system to the satellite.  This is where the
> 40-degree arc around the satellite comes from.
>
> What I don't understand is how INMARSAT knows what that angle is.  CNN
> says that the satellite steers its antenna to the location where it expects
> the next ping, but that doesn't make sense.
>
> I have been looking for the algorithm, but I can't find it.  Signal
> strength? Some sort of electronic steering?  Trade secret?  I don't know.
>
> Tom WB8WOR
>
>
> On Sun, Mar 16, 2014 at 10:57 PM, R.T.Liddy <k8bl at ameritech.net> wrote:
>
>> Tony,
>>
>> They would use the time differential between receipt
>> to measure the distance versus the location of the
>> satellites. The more satellites, then the more accurate
>> the triangulation.
>>
>> 73,   Bob K8BL
>>
>>
>> ________________________________
>>  From: Anthony Japha <tjjapha at earthlink.net>
>> To: amsat-bb <amsat-bb at amsat.org>
>> Sent: Sunday, March 16, 2014 4:49 PM
>> Subject: [amsat-bb] Malaysian airliner puzzle
>>
>>
>> Thanks Rick,
>> How do those sats determine distance to the source?
>> Tony, N2UN
>>
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>
>