Re: ZED-F9P and PPP processing

[John Ackermann N8UR]

On 5/5/20 3:28 PM, Gary E. Miller wrote:
> Yo John!
> 
> On Tue, 5 May 2020 15:20:14 -0400
> John Ackermann N8UR <address@hidden> wrote:
> 
>> As noted in my other message, submitting ZED-F9P GPS-only data to
>> NRCan results in a consistently high (could be 20 to 50 percent)
>> number of rejected epochs, much greater than other receivers recorded
>> using the same antenna at the same time.  I've learned what causes
>> this.
> 
> Cool.
> 
>> The ZED-F9P and -F9T receivers do not do the "old style" (military) L2
>> code.  They will only use the "civilian" L2C signal on the later
>> generation satellites (IIR-M and later).  On the older satellites
>> without L2C, they only do L1.
> 
> You have been spoiled!  YOu got to use P(Y)!

See, those ancient Z-12s and (slightly less ancient) NetRS units have
their value.  I still have a couple of working Z12s but mainly use the
NetRS as my "real" reference these days.

> AFAIK, only 2 sats (block III) do L2C so far.
> 
> https://en.wikipedia.org/wiki/List_of_GPS_satellites#Satellites_by_block
> 
>> Most processing sites will reject dual-frequency observations that
>> only have data for a single channel, so NRCan throws out all the -F9*
>> observations from the older satellites.  That results in more epochs
>> without enough birds to do a solution.
> 
> Should gpsrinex have an option to not include L2C data?

I don't know.  I'm afraid that would effectively turn the F9* into
single frequency receivers.

>> Turning on GLONASS helps this situation because the added SVs mean
>> that more epochs can generate a solution.
> 
> Except others have rerported NRCan only uses GLONASS for 8h+ files.
> Unconfirmed and of course undocumented.

That may be.  I'll test to find out.

John