Subject: [IGSMAIL-4391]: teqc: next version
From: Lou Estey <[email-masked]>
To: [email-masked]
Cc: [email-masked]
Date: Thu, 22 May 2003 13:48:19 -0600 (MDT)

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IGS Electronic Mail      22 May 12:57:51 PDT 2003      Message Number 4391
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Author: Lou Estey

All:

Below is a portion of an email that was sent out to the teqc mailing
list earlier today.  Angie Moore suggested that I forward on the
portion concerning SNR to the igsmail list.  If you want to see the
entire original message, please see:

  http://www.unavco.ucar.edu/html_mail/teqc/msg00326.html
  
Regards,
--lou

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Louis H. Estey, Ph.D.              office:  [+001] 303-497-8036      
UNAVCO/UCAR, P.O. Box 3000            FAX:  [+001] 303-497-8028
Boulder, CO  80307-3000            e-mail:  [email-masked]
   WWW: http://www.unavco.ucar.edu http://jules.unavco.ucar.edu

"If the universe is the answer, what is the question?"
                                               -- Leon Lederman
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X-Unix-From: [email-masked]  Thu May 22 11:36:50 2003
Date: Thu, 22 May 2003 11:27:06 -0600 (MDT)
From: Lou Estey <[email-masked]>
Subject: teqc: next version
To: [email-masked]

Dear all,

Here are some items that you should be aware of regarding
the next upcoming version of teqc, discussed in more detail
below:

1) overhaul of SNR treatment (RINEX 0-9 SNR flag on L1, L2;
   observables S1 and S2)

2) translation capability of Topcon TPS/Javad JPS format

3) need host for HP-UX PA-RISC build

If you have comments, please send them to the teqc list, not
to just me.

--------------------------------

SNR:

Several formats (e.g. Leica LB2 & MDB, Javad JPS, Topcon TPS, CMC
Allstar binary) have been using SNR in dBHz for some time.

Two manufacturers, Ashtech and Trimble, have introduced receivers
which now store SNR in dBHz. The receivers are the Ashtech micro-Z
(and related versions) and any Trimble 4XXX which is after the
series 4000 units (e.g. SST, SSE, SSi) -- like the 4400, 4600, 4700,
4800, 5700, and 7400.  The complication is that there is no
flag in the formats that can be used to tell if the SNR value
is stored in the original unit ("ireg" for Ashtech, "AMU" for Trimble)
or in dBHz; the receiver type (or name) is really the only reliable
way to tell.

For all receiver formats which store the SNR in dBHz (or, the
receiver name identifies it as one that now uses dBHz), the same
mapping of the SNR in dBHz to the RINEX SNR 0-9 flag will be used,
which is currently set to be:

 SNR is mapped to RINEX snr flag value [0-9]                COMMENT
  L1 & L2:  0-11 dBHz = 0, 12-23 dBHz = 1, 24-27 dBHz = 2   COMMENT
           28-31 dBHz = 3, 32-35 dBHz = 4, 36-38 dBHz = 5   COMMENT
           39-41 dBHz = 6, 42-44 dBHz = 7, 45-48 dBHz = 8   COMMENT
           >= 49 dBHz = 9                                   COMMENT
           
(This is identical to the mapping used in Leica's L2R2 code as
of Jan 2002.)  If you aren't happy with this, you'd better speak
up now and have a very good case for a different mapping.

To further complicate matters, I have a set of formulae from Ashtech
which allows a conversion of the old ireg values in some Ashtech
receivers to dBHz.  This is going to be tried on an experimental
basis for the Z-12.  (I am waiting to here back from the engineers
at Ashtech to see if the Z-12 conversion is applicable to any
similar era receivers, like the Z-18.  If so, the conversion will
be applied to the SNR of those receivers as well.)  This conversion
will be automatic if the receiver is identified as being an
Ashtech Z-12 (and possibly Z-18, etc.).

The question you need to answer is: Should there be an option to
suppress the conversion of Z-12 (maybe Z-18) "ireg" SNR to dBHz SNR?
Currently, I am not planning on having such a option, but if one
were included it would allow you to continue to output the
SNR values of a Z-12 (maybe Z-18) as they have been in the past.
Even if such a suppression option were added, the default behaviour
will be to convert the ireg SNR to dBHz.
 
[snip]

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