On 1/14/15 1:40 PM, Brooke Clarke wrote:
Hi Martyn:
On each frequency there are a couple or more different codes.
The Civilian Acess (C/A) code on the L1 frequency is all public
information and so is the most commonly used.
But there are classified codes that have a much higher bit rate and
allow for more accurate position, time and velocity measurements.
Tom mentioned that there are civilian GPS receivers that make use of the
L2 frequency, but they do that my using what's called carrier phase
(that's to say they do not make use of the classified code). This is
mainly used in surveying applications where, by recording a lot of data
and post processing, you can get a very precise location.
Actually, there's L2c available for civil use now, on many satellites.
And L5 is available for civilian use (on fewer satellites than L2c)
L2 has an issue with "safety of life" applications: it's not an
exclusive allocation, so there's an effort to move L1/L2 to L1/L5
When two frequencies are used there's a possibility of removing an error
related to the total electron count in the path of the signal. The new
F5 frequency allows for doing that, but as far as I know none of the
commercial GPS receivers make use of it yet.
There's only half a dozen or so L5 satellites so far..
http://www.prc68.com/I/DAGR.shtml#GPSs
Mail_Attachment --
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
http://www.prc68.com/I/DietNutrition.html
Martyn Smith wrote:
Hello,
I have some questions on GPS and GNSS.
Do all the civilian GPS receivers only operate on the L1 frequency?
Are there any GPS frequency standards out there that use L1 and L2 and
that can be purchased by non-military customers?
I am playing with the new Lea-M8T receiver.
How do I know what satellites are GPS, GLONASS, Galileo etc.
>From my understanding GLONASS have different SV numbers but not 100%
sure.
Any help appreciated.
Regards
Martyn
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