[time-nuts] GPS new L2C civil signal -- timing uses?

[Rob Kimberley]

Using the new L2C with suitable equipment will remove the errors due to 
ionospheric delay associated with single carrier use.

There have been some articles on this recently in GPS World. Try 
www.gpsworld.com if you don't subscribe.

The news release on the launch is at 
http://www.gpsworld.com/gpsworld/article/articleDetail.jsp?id=382449

Also http://sidt.gpsworld.com/GPS+Modernization

Rob K

----- Original Message ----- 
From: "Magnus Danielson" <cfmd at bredband.net>
To: <ch at murgatroid.com>
Cc: <time-nuts at febo.com>
Sent: Friday, November 17, 2006 12:21 AM
Subject: Re: [time-nuts] GPS new L2C civil signal -- timing uses?


> From: "Christopher Hoover" <ch at murgatroid.com>
> Subject: RE: [time-nuts] GPS new L2C civil signal -- timing uses?
> Date: Thu, 16 Nov 2006 15:40:57 -0800
> Message-ID: <005f01c709d8$aa8d95a0$7d01000a at fakie>
>
>>
>> >> Anyone know of the timing uses and properties of this
>> >> new L2C civil signal vis a vis the existing civil signal?
>>
>> > Do you mean beyond that of ICD-GPS-200C?
>>
>> I don't know.  I am unclear of the relationship between that and the "new
>> L2C civil signal" referred to in the article.
>>
>> Are you saying both refer to the same thing?  If so, what are the
>> implications for timing apps?  (I'm happy to go back through the archives 
>> if
>> this has already been discussed.)
>
> OK. The new GPS IIR-M sats (third going up UTC 18:12 tomorrow) transmitts 
> both
> the old L1 C/A signal as well as the new L2C signals. This is totally 
> covered
> in the ICD-GPS-200D [1] (which is the one to use, not the ICD-GPS-200C, 
> which I
> incorrectly directed you to). These three signals is unencrypted and when
> visible they allow for two-frequency measures on capable receivers with
> suitable two-frequency antennas. Based on traditional GPS theory, this 
> allows
> the receiver to shift from a modelled delay of the ionsphere to a measure 
> based
> model ionspheric delay and the implications on time measures is much 
> reduced
> systematic error. Requirements for augmentation through reference stations 
> is
> lowered if not eliminated. Naturally, hardware cost goes up since you now 
> have
> two frequencies to deal with. If you are a teeny weeny serious you look 
> ahead
> towards the L5 and Galilleo signal structures which certainly would 
> require
> additional frequencies.
>
> [1] 
> http://www.navcen.uscg.gov/gps/modernization/IS-GPS-200D_w_IRN_1_7Mar06%20NS.pdf
>
> If we get our durty hands on the propper receivers (and we will) we, as 
> fellow
> time-nuts, will have a much improved state. With Glonass in the rising on 
> top
> of this, things looks good.
>
> Oh, and to be clear, "L2C" is actually three different signals, C/A on L2,
> L2CM and L2CL. where you either have C/A on L2 or both L2CM and L2CL (at 
> the
> same time).
>
> Cheers,
> Magnus
>
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