Subject: [IGLOSMAIL-186] GODZ Z-18 Receiver Firmware Update
From: Dr Thomas A Clark <[email-masked]>
To: IGLOSMAIL <[email-masked]>
Cc: Robert Snow <[email-masked]>, Bob Lemoine <[email-masked]>, Chuck Kodak <[email-masked]>
Date: Tue, 23 Jan 2001 20:14:02 +0000

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IGLOS Electronic Mail      23 Jan 12:14:09 PST 2001   Message Number 186
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Author: Tom Clark, NASA Goddard

Occasionally we have seen the Ashtech Z-18 RINEX data from our GODZ
(Greenbelt) site become corrupted due to carrier phase observables
overflowing from the specified F14.3 format to become F15.3. This
problem happened again from about 15 thru 19 January. [GODZ is the Z-18
providing GLONASS+GPS data from the normal GODE IGS antenna using the
same H-Maser clock]

In the past, our quick fix for the Z-18 overflow problem had been to
power cycle the receiver, which forced the cumulative carrier phase
counter to zero itself, but we only did this when someone reported the
fault. Last week we brought the ovserflow problem to Ashtech's attention
and Bob Snow reported that there was a Z-18 receiver firmware upgrade
from version 6.4 (which we had been using) to version 6.5 (which fixes
the carrier phase overflow). 

Today (Jan.23) at ~noon EST (17:00 UTC) I installed the 6.5 firmware on
GODZ, so the problem should not reoccur. The site was off the air from
16:38 to 17:20.

If there are any other folks using Z-18s who have this problem, I have
placed the two relevant Ashtech files on my anonymous ftp site:

     ftp://tac.gsfc.nasa.gov/pub/gps/ashtech/18p_0065.dat is the 
        version 6.5 binary firmware image, and

     ftp://tac.gsfc.nasa.gov/pub/gps/ashtech/upld.zip contains the
        current Windows binary (.dat) uploader.

Thanks to Maury Dube and Carrie Noll for spotting the GODZ RINEX problem
and to Bob Snow and Bob Lemoine for responding quickly with the needed
firmware.

Regards, Tom