PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 1999-09-07 NOTE = " E-mail and other messages concerning MGS Radio Science on or about 1997/030." END_OBJECT = TEXT END From trish@qmail.jpl.nasa.gov Thu Jan 30 04:37:36 1997 Message-Id: Date: 30 Jan 1997 04:34:58 -0800 From: "Trish Priest" Subject: USO Test #5 To: "Richard Simpson" , "Len Tyler" Cc: "Sami Asmar" , "Tom Thorpe" , "Joe Twicken" X-Mailer: Mail*Link SMTP-QM 3.0.2 Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; Name="Message Body" Content-Transfer-Encoding: quoted-printable Status: RO Mail*Link=AE SMTP USO Test #5 Hello, The fifth USO Test just finished. It went smoothly. Everything was in the usual configuration: Both open-loop and closed-loop data were taken. Spacecraft configuration: TWNC on, TLM on, RNG off Open-loop configuration: 5000 sps, 2.5kHz filter, -3750 Hz offset, 12-bits,Mode 2 Closed-loop configuration: Doppler samples at 10/1 DSN configuration: CONSCAN off Times: 1997/030-10:01:00 to 12:01:00 UTC For a while it looked as though the entire pass would be one-way, so I started recording at 09:40:00 (pass started at 09:30). However, the spacecraft did go two-way at 09:44:00. I just left the DSP running. Since the pass was so short, I did not have an opportunity to retransmit the data. The FFT shows the +/- 650 Hz spurs again. I will fax a plot to Stanford. -Trish ---------------------------------------------------------------------- From joe Fri Jan 31 11:57:14 1997 Received: from neptune.stanford.edu. (neptune.Stanford.EDU [36.10.0.149]) by nova.stanford.edu (8.8.5/8.8.4) with SMTP id LAA03426; Fri, 31 Jan 1997 11:57:08 -0800 (PST) Date: Fri, 31 Jan 1997 11:57:08 -0800 (PST) From: Joe Twicken Message-Id: <199701311957.LAA03426@nova.stanford.edu> To: David.D.Morabito@cc2mhb.jpl.nasa.gov, hinson@nova.stanford.edu, joe@nova.stanford.edu, len@nova.stanford.edu, rsimpson@nova.stanford.edu, trish@qmail.jpl.nasa.gov Subject: USO Test #5 (97/030) Status: RO I have processed the ODS data from 97/030. This ODS was recorded at DSS 15. The data were acquired as part of USO Test #5. The SNR was approximately 59 dB/Hz during the Test. This was the second USO test since the MGS HGA was deployed. The ODS was acquired at DSS 15 from 10:01:00 to 12:01:00 at 5000 samples per second in mode 2 (1250 12-bit samples/second for each of 4 A/D's). I used the spk_c_961111-970321 SP-kernel file to steer the data. This file was created on 97/008. The ODS data was never retransmitted from the station. There were 3 missing records out of 36000. The POCA file was fixed with our "salvagePoca" program. No hand modification of the POCA file was required. A very brief analysis of the original POCA file indicated that over 400 POCA records were in error. During a 2 hour recording, there are 7200 POCA records (1 per second). An amplitude modulation with a period of about 7 minutes (4+ cycles in 30 minutes) is clearly evident in all the carrier amplitude estimates. The peak-to-peak amplitude variation during this test was far less than that observed in USO Test #4. In this test, the peak-to-peak variation was on the order of 0.3 to 0.4 dB. The source of this modulation remains unknown. Trish Priest indicated that the DSN was configured with CONSCAN off. As in some previous tests, there were also a pair of frequency spurs at approximately 650 Hz on either side of the carrier. In this test, the level of these spurs was 35 dB below that of the carrier. I estimated the USO frequency to be 8423152919.93 Hz. The best linear fit to the USO frequency since 96/323 has a slope of 0.248 Hz/day. This fit is actually quite good. The 1-sigma error between the actual USO frequency since 96/323 and the best linear fit is 0.34 Hz. The Allan deviation for this recording is shown below. The SNR during the acquisition of data was approximately 59 dB/Hz. I did not compensate for the spacecraft spin cycle. The Allan deviation at the shorter integration times may be overestimated due to the 3 missing data records. The estimates for 97/030 are: t (sec) AD ------ ---------- 0.4096 6.0395e-13 1.6384 2.4442e-13 3.2768 2.5934e-13 6.5536 1.2742e-13 26.2144 1.0516e-13 Plots, as usual, are in the notebook in room 222... Joe