Subject: [IGSMAIL-0677] Apparent McMurdo (and Richmond?) Data Problems
From: Stephen Peck
Date: Fri, 15 Jul 1994 11:30:01 PDT

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IGS Electronic Mail      Fri Jul 15 11:30:01 PDT 1994      Message Number 0677
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Author: Stephen Peck
Subject: Apparent McMurdo (and Richmond?) Data Problems

Point-position solutions derived from the pseudorange data have 
intermittently exhibited a slow ÒwanderingÓ with about a 100 meter amplitude 
and 4 to 6 hour period.  The pseudorange data and phase data are self-
consistent, causing us to suspect both the pseudorange and phase data.  The 
following days exhibited this problem: May 17 through May 20, June 2 through 
June 7 and June 28 through July 14 (last day currently validated).  Similar 
symptoms appeared in data from Richmond (RCM5)  from June 29 through July 8.  
Caution is suggested when using MCMU or RCM5 data.

We have begun implementing data validation checks for the Global Network 
Operations System (GNOS).  Preliminary checks found this apparent problem 
with the data from McMurdo and Richmond.  We will continue to try to diagnose 
this problem and inform the users when we have further pinpointed or 
eliminated the problems.

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Stephen Peck                       Telephone:   (818) 354 2347
GPS Networks & Operations Group    FAX:         (818) 393 4965
Jet Propulsion Laboratory          Email:       [email-masked]
4800 Oak Grove Dr.
Pasadena, CA 91109
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