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The Navy's Geosat Follow-On (GFO) Mission, launched on February 10, 1998, is one in a series of scientific altimetric satellites which include Seasat, Geosat, ERS-1, and TOPEX/POSEIDON (T/P). Data derived from these missions has and will lead to vast improvements in our knowledge of ocean circulation, ice sheet topography, and climate change. In order to capture the maximum amount of information from the altimetric data, accurate altimeter calibrations are required for the civilian data set which NOAA will produce. NASA/Goddard Space Flight Center/Wallops Flight Facility (GSFC/WFF) has provided these products for the Geosat and T/P missions and will do the same for GFO.
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Announcements

WVR is back on, RA is being power cycled during eclipse periods.

(03/19/2007 02:24 PM
The satellite is currently at the end of the 135th repeat cycle -- after a partial resolution of the continuing issues with the batteries, the WVR is back on full time, but the RA is being power cycled so that it is off during eclipse periods. Both these payloads will be cycled on and off as necessary to maintain the satellite electrical power system and prevent satellite resets.

GFO RA and WVR payloads off

(01/31/2007 01:25 PM
As of 27 January 2007 (2007 027) the satellite has completed 131 exact repeat cycles and has spent over five years on orbit since acceptance of the satellite by the Navy and over eight years on orbit since launch. The satellite is currently in the middle of the 132nd repeat cycle -- due to continuing issues with the batteries, the RA is off as is the WVR. Both these payloads will be cycled on and off as necessary to maintain the satellite electrical power system and prevent satellite resets.

GFO radar altimeter back online.

(10/25/2006 03:15 PM
GFO satellite systems came back online as of approximately 13:00z on 5 Oct 06, day 278. The ADFC has implemented a -82.4 millisecond timing bias into the SDR processing. The ADFC transitioned the latest POC software, SDR with WVR flagging, to operational mode on 2006291.

GFO radar altimeter powered off

(08/25/2006 12:46 PM
GFO's power control unit initiated a low bus voltage payload bus load shed last night (Aug. 25 between 00:40z and 3:00z). As a result the RA and WVR are currently powered off. This event is currently under investigation.

GFO radar altimeter back online.

(08/25/2006 08:30 AM
GFO satellite systems came back online as of approximately 16:50z on 23 Aug 06. The WVR was turned on at 16:30z on 23 Aug 06. The payload started producing high quality data as of 16:06:23z on 24 AUG 06. The ADFC has begun processing the data on 24 Aug 06 and data delivery has resumed.

GFO radar altimeter powered off

(08/17/2006 02:09 PM
On August 3, 2006, GFO experienced 3 low voltage (UV1) alarms resulting in the shedding of the payload bus. The battery state and charge is under investigation. The altimeter has been off since this event occurred.

Full Waveform Data Collection suspended 15 October 2005 - 7 April 2006

(05/19/2006 09:15 AM
The number of full cal periods will be occasionally reduced to support battery maintenance. Ten minute CAL was performed but there was no Full Wave Form data collection. GFO Full Wave Form was restored on 7 April 2006.

Outage due to hurricane Katrina on 24 August 2005

(05/19/2006 09:10 AM
Due to hurricane Katrina, which caused power and communication outages across the gulf coast, the NAVO ground system was totally out, the satellite remains operational and data is being archived by the Naval Satellite Operations Center. The GFO POC resumed sending data on 15 September 2005. Nearly all data during the outage period has now been processed and made available.

One RA Calibration Period Discontinued on 13 March 2005

(05/19/2006 09:06 AM
One of the two daily RA CALS to collect data over Africa was discontinued.

Recent Document Additions (Since January 2003)

(07/05/2004 07:29 AM
Use the "Documents" link on the left side of the page to view these documents.

7/11/2007: Added ""DRAFT" GFO and JASON Altimeter Engineering Assessment Report", NASA/TM-2007-209984/Version 1/Volume 9, June 2007, by A.M. Conger/SGT, Inc., D.W. Hancock III/NASA GSFC, G.S. Hayne/Raytheon ITSS, and R.L. Brooks/Raytheon ITSS.

11/02/2006: Added "GFO Altimeter Engineering Assessment Report", NASA/TM-2006-209984/Version 1/Volume 8, October 2006, by A.M. Conger/SGT, Inc., D.W. Hancock III/NASA GSFC, G.S. Hayne/Raytheon ITSS, and R.L. Brooks/Raytheon ITSS.

10/20/2005: Added "GFO Altimeter Engineering Assessment Report", NASA/TM-2005-209984/Version 1/Volume 7, May 2005, by D.W. Lockwood/SGT, Inc., D.W. Hancock III/NASA GSFC, G.S. Hayne/Raytheon ITSS, and R.L. Brooks/Raytheon ITSS.

07/06/2004: Added "GFO Altimeter Engineering Assessment Report", NASA/TM-2004-209984/Version 1/Volume 6, May 2004, by D.W. Lockwood/Raytheon ITSS, D.W. Hancock III/NASA GSFC, G.S. Hayne/NASA GSFC, and R.L. Brooks/Raytheon ITSS.

10/30/2003: Added "GFO Radar Altimeter Processing at Wallops Flight Facility", NASA/TM-2003-209984/Version 1/Volume 5, August 2003, by D.W. Lockwood and Annette M. Conger/Raytheon ITSS.

05/21/2003: Added "Temperature Correction for GFO Wind Speed", May 2003, by R.L. Brooks/Raytheon ITSS and D.W. Lockwood/Raytheon ITSS.

04/24/2003: Added "GFO Altimeter Engineering Assessment Report", NASA/TM-2003-209984/Version 1/Volume 4, April 2003, by D.W. Lockwood/Raytheon ITSS, D.W. Hancock III/NASA GSFC, G.S. Hayne/NASA GSFC, and R.L. Brooks/Raytheon ITSS.