[time-nuts] Light Squared, etc.

bg at lysator.liu.se bg at lysator.liu.se
Thu Jun 9 21:35:13 UTC 2011


> Yes, what about L5? I thought that was going to be the "new" civilian
> frequency that was going to revolutionize GPS. If the FCC is hellbent on
> approving Light Squared's request, L5 might be our only option.

IOC level (18) of L5 sending satellites probably available in the
2016-2019 range. FOC (min 24) between 2018 and 2022. We are now used to
30+ working GPS satellites.

   http://www.gpsworld.com/gnss-system/gps-modernization/future-wave-11401?page_id=7

Of course
> the transition would be very nasty and expensive. Regarding nuclear
> powered
> satellites, I suspect that spy satellites are nuclear powered but since
> they
> are classified, who knows. Perhaps future GPS satellites with higher
> powered
> transmitters could be nuclear powered and classified.

When did GPSIII studies start? ca 2000? First launch now predicted
2014-15. Lesson: It takes a lot of time to get new shining features up in
space.

Also consider the new military M-code. "The M-code is a
binary-offset-carrier (BOC) signal — a split spectrum signal — that places
most of its power near the edges of the allocated GPS frequency bands,
thereby having negligible impact on the legacy signals."

   http://www.gpsworld.com/gnss-system/gps-modernization/innovation-mboc-signal-options-11721

Looking at the picture in a L1C article

   http://www.gpsworld.com/files/gpsworld/nodes/2011/11401/L1C-3.jpg

You will see the M-code lower band making a nice shield against the evil
L^2 for the narrow band civil GPS signal(s).


--

   Björn




More information about the time-nuts mailing list