[time-nuts] GPS-III

Michael Perrett mkperrett at gmail.com
Thu Jul 24 13:30:07 EDT 2014


Chris,
I disagree only with your statement "as a  GPS user you'd never know".

As stated in one of John's references:

The government is in the process of fielding three new signals designed for
civilian use: L2C, L5, and L1C. The legacy civil signal, called L1 C/A or
C/A at L1, will continue broadcasting in the future, for a total of four
civil GPS signals. Users must upgrade their equipment to benefit from the
new signals.


These new signals (will) provide many advantages as seen by the civilian
user, one of the most obvious is the ability to make real time IONO
corrections on civilian receivers (currently restricted to P Code
receivers). Also the new signal structures are more tolerant of both
intended and unintended interference.

Michael
Raytheon Senior Fellow (retired)
Navigation Systems





On Thu, Jul 24, 2014 at 9:32 AM, Chris Albertson <albertson.chris at gmail.com>
wrote:

> "GPS-III" is the wrong term.   You mean "block three spacecraft".
> The Air Force is buying 8 new satellites they are calling "block III"
> and they don't launch until at least 2016.  If the current satellites
> are in good health they could delay the launch.   If the past is a
> guide to the future the AirForce will eventually buy more advanced
> block III called "IIIa" or something.    As a GPS users you'd never
> really know.  Those numbers are contracting terms, not signal terms.
> The signals in question are already being transmitted by a few of the
> latter block II satellites.
>
> I think you can buy multi-frequency receivers.  Remember GPS is not
> longer the only system.  There are stelites from the US, Europe,
> Russia, China and Japan.    Adding more more frequencies allows the
> receiver to detect multi path and makes it harder to jam but the
> timing is not greatly improved over say the M12.
>
> On Thu, Jul 24, 2014 at 12:14 AM, John C. Westmoreland, P.E.
> <john at westmorelandengineering.com> wrote:
> > Hello All,
> >
> > Does anyone know yet of any companies that are making GPS-III receiver
> > chip-sets/modules yet?
> >
> > Some web-sites on GPS-III:
> >
> > http://www.gps.gov/systems/gps/modernization/
> > http://www.gps.gov/systems/gps/modernization/civilsignals/
> > http://www.losangeles.af.mil/library/factsheets/factsheet.asp?id=18830
> >
> > Regards,
> > John W.
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>
>
> --
>
> Chris Albertson
> Redondo Beach, California
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