NOTE: At 11:58 UTC on 08 March 1999, the AOA TurboRogue SNR-12
receiver (S/N T245) was replaced with a TurboRogue retrofitted by AOA
with their ACT upgrade (S/N 247-U). There was no change to the antenna
and the new receiver is supplied with the same 5 MHz external
frequency standard as before. First data with the new receiver is
available starting at approximately 15:37 UTC on 09 March 1999.
From bill@tycho.usnogps.navy.mil Mon Mar 8 14:26:55 EST 1999
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From: Bill Bollwerk
Message-Id: <199903081925.TAA05111@tycho.usnogps.navy.mil>
Subject: Re: Turbo Rogues
To: jimr@maia.usno.navy.mil
Date: Mon, 08 Mar 1999 19:25:15 UTC
Cc: miranda@tango.grdl.noaa.gov, linda@gracie.grdl.noaa.gov
In-Reply-To: <199903081806.NAA10800@maia.usno.navy.mil>; from "Jim Ray" at Mar 08, 99 1:06 pm
X-Mailer: Elm [revision: 212.4]
Status: RO
Jim,
After speaking and coordinating with Linda, I replaced the TR receiver at 1158
UTC. I also moved the flash card from the old to the new receiver.
The new receiver is serial number 247-U. The new receiver has an external
5 MHz input from AMC#1 (the AMC Master Clock).
Bill
From linda@lynx.grdl.noaa.gov Tue Mar 9 10:52:44 EST 1999
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Message-Id: <199903091552.KAA24494@lynx.grdl.noaa.gov>
Subject: Tracking at AMC2
To: jimr@maia.usno.navy.mil (Jim Ray)
Date: Tue, 09 Mar 1999 10:52:22 EST
Cc: bill@tycho.usnogps.navy.mil
In-Reply-To: <199903081806.NAA10800@maia.usno.navy.mil>; from "Jim Ray" at Mar 08, 99 1:06 pm
X-Mailer: Elm [revision: 212.2]
Status: RO
Jim, Bill,
This morning I discovered that AMC2 receiver (247-U) was tracking
in rover mode and the clock steering was on while using an external
frequency. Acting upon Miranda's recommendation, I stopped tracking
and erased the Flashcard, reset the receiver to the correct settings
and restarted tracking. Everything looks fine. Tracking started
at approximately 15:37 UTC. We should have 24-hour data by Thursday
morning.
The receiver software version is 3.3.32.2
We will continue to monitor this station, but I think everything
will be good.
Thank you for all of the time and input you have given me to reset
this station. I appreciate your cooperation.
-Linda
From bill@tycho.usnogps.navy.mil Wed Mar 10 10:13:41 EST 1999
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From: Bill Bollwerk
Message-Id: <199903101513.PAA24484@tycho.usnogps.navy.mil>
Subject: TR 247-U 1 PPS
To: jimr@maia.usno.navy.mil (Jim Ray)
Date: Wed, 10 Mar 1999 15:13:15 UTC
Cc: miranda@tango.grdl.noaa.gov, linda@gracie.grdl.noaa.gov,
sth@tycho.usnogps.navy.mil
X-Mailer: Elm [revision: 212.4]
Status: RO
Jim,
I have looked at the 1 pps data for the new TR receiver (247-U) following the
replacement on Monday and have noted the following:
- the values jumped about 100 nanoseconds when the receivers were swapped
- the replacement receiver (247-U) 1 pps values are noisier than receiver 245
This is just for your information.
Bill
From igscb@igscb.jpl.nasa.gov Wed Mar 10 18:12:52 EST 1999
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(1.39.111.2/16.2) id AA176584667; Wed, 10 Mar 1999 14:24:27 -0800
Date: Wed, 10 Mar 1999 14:24:27 -0800
To: IGS Mail Recipients
From: IGS Mail Service
Reply-To: IGS Mail Administrator
Errors-To: IGS Mail Administrator
Sender: IGS Mail Administrator
Subject: No 2198: USNO AMC - AMC2 Receiver Change
Status: RO
******************************************************************************
IGS Electronic Mail Wed Mar 10 14:24:27 PST 1999 Message Number 2198
******************************************************************************
Author: Bill Bollwerk
Subject: USNO AMC - AMC2 Receiver Change
The AMC2 receiver was changed on Monday, 8 March, MJD 51245. The old receiver
(S/N 245) was removed and replaced by an upgraded receiver (S/N 247-U). An
updated log file will be provided after a comprehensive review of the data is
completed. Sorry for any inconvenience this may cause.
[Mailed From: Bill Bollwerk ]
From igscb@igscb.jpl.nasa.gov Wed Apr 14 09:29:36 EDT 1999
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(1.39.111.2/16.2) id AA173314038; Wed, 14 Apr 1999 05:47:18 -0700
Date: Wed, 14 Apr 1999 05:47:18 -0700
To: IGS Mail Recipients
From: IGS Mail Service
Reply-To: IGS Mail Administrator
Errors-To: IGS Mail Administrator
Sender: IGS Mail Administrator
Subject: No 2235: AMC2 RINEX procedures and observables
Status: RO
******************************************************************************
IGS Electronic Mail Wed Apr 14 5:47:17 PDT 1999 Message Number 2235
******************************************************************************
Author: Jim Ray
Subject: AMC2 RINEX procedures and observables
On 08 March 1999, the AMC2 receiver at Schriever Air Force Base, Colorado
Springs, CO, USA was changed from an AOA ROGUE SNR-12 (s/n T245) to a
retrofitted AOA SNR-12 ACT (s/n 247-U), which is functionally equivalent
to an AOA BENCHMARK ACT receiver -- see IGS Mail #2198 (10 March 1999).
Beginning 16 March 1999, the data download procedures for AMC2 were
changed to use TurboBinary offload files with RINEX translation done by
"teqc -aoa tbY". As described by Herb Dragert in IGS Mail #2234
(12 April 1999), the AMC2 (AOA SNR-12 ACT) observables are now:
C1 = C/A code at L1 freq.
L1(C1) = C/A-based phase at L1 freq.
P1 = Y1-codeless pseudorange at L1 freq.
P2 = Y2-codeless pseudorange at L2 freq.
L2(P2) = Y2-codeless-based phase at L2 freq.
These differ significantly from the TurboRogue-style cross-correlation
observables:
C1 = C/A code at L1 freq.
L1(C1) = C/A-based phase at L1 freq.
P2' = codeless pseudorange at L2 freq.
L2' = cross-correlated phase at L2 freq.
because the P2' pseudorange-type observable and the L2' phase are actually
formed by a process which tracks the cross-correlated (P2-P1) pseudorange
and the (L2-L1) phase differences:
P2' = C1 + (P2-P1)
L2' = L1(C1) + (L2(P2)-L1(P1))
Users of AMC2 data should be aware that the new pseudorange observable
pair (P1, P2) differs from the usual TurboRogue-style pseudorange pair
(C1, P2') by (C1-P1) biases which are not zero-mean and can reach up
to +/- 2 ns. Because the biases are satellite-dependent and receiver-
dependent, they are not removed by double differencing. There is no
significance for data analysts who process only the carrier phase
observables.
NOTE: An IGS-wide approach to handling a mix of TurboRogue-style and
non-TurboRogue data will be considered at the IGS Analysis Center
Workshop at SIO in June.
=========================================================================
Jim Ray e-mail: jimr@maia.usno.navy.mil
U.S. Naval Observatory, EO Dept. phone : 202-762-1444
3450 Massachusetts Avenue, NW fax : 202-762-1563
Washington, DC 20392-5420
=========================================================================
[Mailed From: Jim Ray (USNO 202-762-1444) ]