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 1997/049." END_OBJECT = TEXT END From trish@qmail.jpl.nasa.gov Wed Feb 19 11:04:27 1997 Message-Id: Date: 19 Feb 1997 11:00:09 -0800 From: "Trish Priest" Subject: Re: USO Test #7 To: "Richard Simpson" 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 Reply to: RE>USO Test #7 USO Test times: 19:01:27 to 21:01:27 UTC ERT. -Trish ---------------------------------------------------------------- Date: 2/18/97 8:49 PM To: Trish Priest From: Richard Simpson Since we don't have any information on when the DSP actually was running, I've queried for a ridiculously long time interval (the length of the entire pass at DSS 65). We'll see what gets caught in the net. I can run my software tomorrow and/or Trish may be able to provide some start/stop times after looking at the notes that Jen left. ---------------------------------------------------------------- From joe Thu Feb 20 15:00:26 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 PAA02867; Thu, 20 Feb 1997 15:00:03 -0800 (PST) Date: Thu, 20 Feb 1997 15:00:03 -0800 (PST) From: Joe Twicken Message-Id: <199702202300.PAA02867@nova.stanford.edu> To: David.D.Morabito@cc2mhb.jpl.nasa.gov, caetta@biollante.jpl.nasa.gov, hinson@nova.stanford.edu, john@oberon.jpl.nasa.gov, len@nova.stanford.edu, rsimpson@nova.stanford.edu, trish@qmail.jpl.nasa.gov Subject: USO Test #7 (97/049) Status: RO I have processed the ODS data from 97/049. This ODS was recorded at DSS 65. The data were acquired as part of USO Test #7. The SNR was approximately 56 dB/Hz during the Test. This was the fourth USO test since the MGS HGA was deployed. The quality of the data obtained in this test was the best to date. The ODS was acquired at DSS 65 from 19:01:27 to 21:01:26 at 5000 samples per second in mode 2 (1250 12-bit samples/second for each of 4 A/D's). I believe that the ODS was retransmitted multiple times on the day of the test because there were a number of null SFDU's (SFDU headers with no ODS record attached) in the data stream. There were no missing records when the ODS was retrieved at Stanford. There were no attenuation changes or other problems with operations during the Test, either. I used the spk_c_961111-970328 SP-kernel file to steer the data. This file was created on 97/029. The POCA file was fixed with our "salvagePoca" program. Once again, no hand modification of the POCA file was required. A very brief analysis of the original POCA file indicated that there were over 150 POCA records in error. All the errors seemed to be confined to five error bursts. During the 2 hour recording there were a total of 7200 POCA records. An amplitude modulation with a period of about 8-10 minutes is evident in all the carrier amplitude estimates. Amplitude modulations have been seen in all USO Tests since the deployment of the HGA. The peak-to-peak variation during this test was on the order of 0.2 to 0.3 dB. The source of this modulation remains unknown. As in many 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 about 33 dB below that of the carrier. The spurs appear to drift through the spectrum along with the carrier. I estimated the USO frequency to be 8423152925.03 Hz. The best linear fit to the USO frequency since 96/323 has a slope of 0.252 Hz/day. This fit is actually quite good. The 1-sigma error between our USO frequency estimates since 96/323 and the best linear fit to them is 0.33 Hz. The Allan deviation for this recording is shown below. The SNR during the acquisition of data was approximately 56 dB/Hz. I did not compensate for the spacecraft spin cycle. Overall, this was the best Allan deviation performance of all the USO Tests. t (sec) AD ------ ---------- 0.4096 3.7005e-13 1.6384 2.2193e-13 3.2768 1.6435e-13 6.5536 1.3345e-13 26.2144 1.2377e-13 Plots, as usual, are in the notebook in room 222. Joe