Operations history

HISTORY OF CHAMP's OPERATIONAL CHANGES AND MANOEUVRES:

(Last update: 2001-10-16)

This table is a calendar of the operational changes made into the receivers. The comments are based on the descriptions
given by Tom Meehan. The date is followed by an ON or an OFF depending on what is the status of atmospheric
occultations for that day.

CHAMP:

Date Software-related event Hardware-related event

Sun, 11 Feb 2001 - ON & OFF First Occultations enabled (~ 1hr)

Fri, 16 Feb 2001 - ON & OFF Occultations enabled again

Fri ,23 Feb 2001 - ON & OFF Occultations enabled again

Mon, 05 Mar 2001 - ON Occultations turned on around 16:45UT.

Fri, 09 Mar 2001 - OFF Occultations turned off

Mon, 19 Mar 2001 - OFF Modification of the A-side SW began early this morning around 07:00 UT. This will bring the A-side up to the same level of code as the B-side. It is expected that this will take until Thursday or Friday to complete.
If possible, occultations will be enabled during long periods
between ground contacts (< 2 hours) so we may get a few more this week. POD data and occultation data will have lots of gaps until the SW change-out is complete.

Thurs, 29 Mar 2001 - ON Occultations enabled

Tues, 03 Apr 2001 - OFF Occultations turned off

Fri, 06 Apr 2001 - ON Occultations enabled

Sat, 07 Apr 2001 - OFF Occultations turned off

Wed, 11 Apr 2001 - ON Iono Occultations enabled

Thur, 12 Apr 2001 - OFF Occultations turned off

Mon, 16 Apr 2001 - ON Occultations enabled

Sat, 21 Apr 2001 - OFF Occultations turned off

Mon, 23 Apr 2001 - ON Iono Occultations enabled

Sun, 29 Apr 2001 - OFF Occultations turned off

Mon, 14 May 2001 - ON CHAMP will probably enable occultations full time beginning this morning.

Sat, 09 Jun 2001 - OFF Occultations turned off

Sun, 10 Jun 2001 - ON Iono Occultations enabled

Sun, 17 Jun 2001 - OFF Occultations turned off

Mon, 18 Jun 2001 - ON Occultations enabled

Sat, 14 Jul 2001 - OFF Occultations turned off

Thur 26 Jul 2001 - ON CHAMP SW upload complete. This mod should allow simultaneous ionospheric and atmospheric occultations and fix a few bugs. Atmospheric occultations will be enabled tomorrow after some verification that the POD mode is functioning normally.

Sun, 29 Jul 2001 - ON The CHAMP BlackJack was commanded into occultation mode at 06:00 UT Sunday. After a brief look at the occultation data The scheduler modifications are working properly. This set is expected to produce fewer occultations (~170 per day) based on the parameters for the clock-diff satellite. If we send a new occultation parameter set we can increase the number of occultations back over 200/day. This morning at 06:00 UT, a combined ionospheric/atmospheric data set is scheduled for commanding.
This new SW is showing some anomalies though. Resets seem to be about as frequent when occultations are ON as before the SW mods (~2 per day). However, they are also about this rate when occultations are OFF, leaving us with a worse situation when only POD data is to be taken. This behavior is different than what we saw with simulator
testing although testing in POD only mode was limited to about 24 hours (zero resets).

Mon, 30 Jul 2001 - ON The combined Iono/Atmo mode was enabled today at 06:00 UT. The initial data set looks fine at first glance. There is a bug with this new SW though. Occasionally, the iono sat will be the same as the clk-diff sat. A separate tracker will be run for each. However, whenever one of the two quits tracking as ordered by there respective scheduler (iono or atmo) the other tracker also quits.
Atmospheric occultations now report their lat/lon in the log message at the beginning of the occultation.

Fri, 03 Aug 2001 - OFF Occultations turned off

Mon, 13 Aug 2001 - ON New SW was uploaded to CHAMP which is supposed to fix the lack of 50Hz L2 data on the clk-diff sat.
Also, the scheduler was updated to better estimate the starting altitudes of the occultation link.
Also, an attempt was made to reduce the 1Hz oscillator spikes which mysteriously increased after the last SW upload.
Also, a possible bug fix was implemented to reduce the 1Hz oscillator spikes on the L1-L2 50 Hz data.
Also, simultaneous ionospheric/atmospheric occs should now work properly (or at least better).
In looking at the first occultation data from 06:00 UT to 12:00 UT today, the new scheduler is not yet running because there has not been a reset of the SW in over 24 hours! New SW is only executed after a reset.
CHAMP has 8 POD sats enabled.

Sun, 19 Aug 2001 - OFF CHAMP uploaded new tracking SW this morning. This tracking SW is slightly modified from the SAC-C code just
uploaded on Friday.

Wed, 22 Aug 2001 - ON Occultations enabled

Frii, 24 Aug 2001 - ON Something funny happened, more than 300 Occs/day recorded

Sun, 26 Aug 2001 - ON Back to normal

Thurs, 30 Aug 2001 - ON 00:10 UT, the CHAMP receiver was put into the
mode to get simultaneous ionospheric and atmospheric occultations. During some of the occultations, the reference satellite quits producing data early even though it is not the same PRN as the ionospheric satellite

Sun, 07 to Mon, 08 Oct 2001 - OFF & ON Attitude manoeuvre
CHAMP was turned 90 degrees with respect to its flight axis between ~20:40 UT and ~07:40 UT. All payload and onboard systems worked as expected. Atmospheric occultations enabled again around midnight today.

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Date	Software-related event	Hardware-related event
Sun, 11 Feb 2001 - ON & OFF	First Occultations enabled (~ 1hr)
Fri, 16 Feb 2001 - ON & OFF	Occultations enabled again
Fri ,23 Feb 2001 - ON & OFF	Occultations enabled again
Mon, 05 Mar 2001 - ON	Occultations turned on around 16:45UT.
Fri, 09 Mar 2001 - OFF	Occultations turned off
Mon, 19 Mar 2001 - OFF	Modification of the A-side SW began early this morning around 07:00 UT. This will bring the A-side up to the same level of code as the B-side. It is expected that this will take until Thursday or Friday to complete. If possible, occultations will be enabled during long periods between ground contacts (< 2 hours) so we may get a few more this week. POD data and occultation data will have lots of gaps until the SW change-out is complete.
Thurs, 29 Mar 2001 - ON	Occultations enabled
Tues, 03 Apr 2001 - OFF	Occultations turned off
Fri, 06 Apr 2001 - ON	Occultations enabled
Sat, 07 Apr 2001 - OFF	Occultations turned off
Wed, 11 Apr 2001 - ON	Iono Occultations enabled
Thur, 12 Apr 2001 - OFF	Occultations turned off
Mon, 16 Apr 2001 - ON	Occultations enabled
Sat, 21 Apr 2001 - OFF	Occultations turned off
Mon, 23 Apr 2001 - ON	Iono Occultations enabled
Sun, 29 Apr 2001 - OFF	Occultations turned off
Mon, 14 May 2001 - ON	CHAMP will probably enable occultations full time beginning this morning.
Sat, 09 Jun 2001 - OFF	Occultations turned off
Sun, 10 Jun 2001 - ON	Iono Occultations enabled
Sun, 17 Jun 2001 - OFF	Occultations turned off
Mon, 18 Jun 2001 - ON	Occultations enabled
Sat, 14 Jul 2001 - OFF	Occultations turned off
Thur 26 Jul 2001 - ON	CHAMP SW upload complete. This mod should allow simultaneous ionospheric and atmospheric occultations and fix a few bugs. Atmospheric occultations will be enabled tomorrow after some verification that the POD mode is functioning normally.
Sun, 29 Jul 2001 - ON	The CHAMP BlackJack was commanded into occultation mode at 06:00 UT Sunday. After a brief look at the occultation data The scheduler modifications are working properly. This set is expected to produce fewer occultations (~170 per day) based on the parameters for the clock-diff satellite. If we send a new occultation parameter set we can increase the number of occultations back over 200/day. This morning at 06:00 UT, a combined ionospheric/atmospheric data set is scheduled for commanding. This new SW is showing some anomalies though. Resets seem to be about as frequent when occultations are ON as before the SW mods (~2 per day). However, they are also about this rate when occultations are OFF, leaving us with a worse situation when only POD data is to be taken. This behavior is different than what we saw with simulator testing although testing in POD only mode was limited to about 24 hours (zero resets).
Mon, 30 Jul 2001 - ON	The combined Iono/Atmo mode was enabled today at 06:00 UT. The initial data set looks fine at first glance. There is a bug with this new SW though. Occasionally, the iono sat will be the same as the clk-diff sat. A separate tracker will be run for each. However, whenever one of the two quits tracking as ordered by there respective scheduler (iono or atmo) the other tracker also quits. Atmospheric occultations now report their lat/lon in the log message at the beginning of the occultation.
Fri, 03 Aug 2001 - OFF	Occultations turned off
Mon, 13 Aug 2001 - ON	New SW was uploaded to CHAMP which is supposed to fix the lack of 50Hz L2 data on the clk-diff sat. Also, the scheduler was updated to better estimate the starting altitudes of the occultation link. Also, an attempt was made to reduce the 1Hz oscillator spikes which mysteriously increased after the last SW upload. Also, a possible bug fix was implemented to reduce the 1Hz oscillator spikes on the L1-L2 50 Hz data. Also, simultaneous ionospheric/atmospheric occs should now work properly (or at least better). In looking at the first occultation data from 06:00 UT to 12:00 UT today, the new scheduler is not yet running because there has not been a reset of the SW in over 24 hours! New SW is only executed after a reset. CHAMP has 8 POD sats enabled.
Sun, 19 Aug 2001 - OFF	CHAMP uploaded new tracking SW this morning. This tracking SW is slightly modified from the SAC-C code just uploaded on Friday.
Wed, 22 Aug 2001 - ON	Occultations enabled
Frii, 24 Aug 2001 - ON	Something funny happened, more than 300 Occs/day recorded
Sun, 26 Aug 2001 - ON	Back to normal
Thurs, 30 Aug 2001 - ON	00:10 UT, the CHAMP receiver was put into the mode to get simultaneous ionospheric and atmospheric occultations. During some of the occultations, the reference satellite quits producing data early even though it is not the same PRN as the ionospheric satellite
Sun, 07 to Mon, 08 Oct 2001 - OFF & ON		Attitude manoeuvre CHAMP was turned 90 degrees with respect to its flight axis between ~20:40 UT and ~07:40 UT. All payload and onboard systems worked as expected. Atmospheric occultations enabled again around midnight today.