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 1997/220." END_OBJECT = TEXT END From trish@rodan.jpl.nasa.gov Fri Aug 8 03:46:26 1997 Received: from rodan.Jpl.Nasa.Gov (rodan.jpl.nasa.gov [128.149.43.24]) by magellan.Stanford.EDU (8.8.5/8.8.3) with ESMTP id DAA19666 for ; Fri, 8 Aug 1997 03:46:25 -0700 (PDT) Received: from 128.149.43.27 (trish-mac.jpl.nasa.gov [128.149.43.27]) by rodan.Jpl.Nasa.Gov (8.8.5/8.6.6) with SMTP id DAA17663; Fri, 8 Aug 1997 03:45:06 -0700 (PDT) Message-Id: <199708081045.DAA17663@rodan.Jpl.Nasa.Gov> Date: 08 Aug 97 03:46:50 -0700 From: Trish Priest Subject: RS ORT #4 To: John Armstrong , Sami Asmar , Georges Balmino , Joe Beerer , Michael Flasar , David Hinson , Kyle Martin , Dave Recce , Richard Simpson , Bill Sjogren , David Smith , Tom Thorpe , Joe Twicken , Len Tyler , Richard Woo , Maria Zuber CC: Salvadore Abbate , Mike Kennedy , Al Kern , Dan Steege X-Mailer: QuickMail Pro 1.0.2d1 X-Priority: 3 Reply-To: Trish Priest Content-Type: text/plain; charset="iso-8859-1" Content-Length: 1018 Status: RO Hello, The fourth RS ORT (DSS 45) is going very smoothly despite a problem with the DSN keyword file. (Some information about spacecraft configuration changes was left out due to a bug in the file generation software. The NOPE sent a fax to the station with the necessary information, and he will be writing an FR on the problem.) No other problems have been encountered. This is the first ORT which has used remote operations scripting. We created scripts to configure the DSP-R for each "ingress" and "egress," and we watched them execute flawlessly! A giant step toward unattended operations! I have ftp'd the scripts to my directory on mgrs. They are called doy220inX.scr and doy220egX.scr, where X is the orbit number (1-3). There is one script file for each period of data collection. We used the "old way" of data delivery, and we have an opportunity for retransmission of missing data during the next pass at this station. The applicable SOE for this ORT is c0903.09.soe. -Trish --------------------------------------------------------------------- From joe@neptune.Stanford.EDU Mon Aug 11 18:12:30 1997 Received: from nova.stanford.edu (nova.Stanford.EDU [36.10.0.123]) by magellan.Stanford.EDU (8.8.5/8.8.3) with ESMTP id SAA27620 for ; Mon, 11 Aug 1997 18:12:29 -0700 (PDT) Received: from neptune.Stanford.EDU (neptune.Stanford.EDU [36.10.0.149]) by nova.stanford.edu (8.8.5/8.8.4) with ESMTP id SAA27468; Mon, 11 Aug 1997 18:12:53 -0700 (PDT) Received: (from joe@localhost) by neptune.Stanford.EDU (8.8.5/8.8.3) id SAA04054; Mon, 11 Aug 1997 18:12:30 -0700 (PDT) Date: Mon, 11 Aug 1997 18:12:30 -0700 (PDT) From: Joe Twicken Message-Id: <199708120112.SAA04054@neptune.Stanford.EDU> To: David.D.Morabito@cc2mhb.jpl.nasa.gov, angus.m.mcmechen@ast.lmco.com, hinson@nova.Stanford.EDU, joe@nova.Stanford.EDU, john@oberon.jpl.nasa.gov, len@nova.Stanford.EDU, rsimpson@nova.Stanford.EDU, trish@zygra.jpl.nasa.gov, william.r.adams@ast.lmco.com Subject: MGS USO Test #13 (97/220) Content-Length: 4543 Status: RO I have processed the USO Test #13 ODS from 97/220. This ODS was recorded at DSS 65. Telemetry and ranging were on during the test. The SNR was approximately 42 dB/Hz. This was the first USO Test ODS to be processed on our Sun Ultra 2 workstation ("magellan") running the Solaris operating system. I have only recently completed porting our software and scripts to that system and installing our QDDB MgsDB database there. All files for processing this ODS were recorded in the MgsDB. Our plan for mapping operations is that the SOPC will be used for data transfer, logging and quick-look analysis, while the magellan station will be used for data processing. One nice feature of the QDDB program is that it can run simultaneously on both machines (or with multiple users on either machine) with a single shared database, and will ensure that only one person (or script) has write permission to any particular record at any given time. We are expecting that the SOPC will be "upgraded" to Solaris around the time which mapping begins. We now know that our software and database can be ported to Solaris systems and run there with few complications. The ODS was acquired at DSS 65 from 14:12:10 to 16:12:09 at 5000 samples per second in mode 2 (1250 12-bit samples/second for each of 4 A/D's). The ODS was obtained following a retransmission and there were not any missing records. There was one duplicate record, however. That was ignored by our processing software. I am happy to report that there were no POCA errors of any kind in the ODS. The recently installed DSP-R software continues to be nearly POCA error free. I used the spk_c_970525-970907 SP-kernel file to steer the data. This file was created on 97/211. The power spectra of the USO Test #13 open-loop data exhibited 650 Hz spurs above and below the carrier frequency. We have now come to expect this when telemetry is on. There did not appear to be any other spurs in the power spectra. Amplitude fluctuations were very small, on the order of 0.2 dB peak to peak. There was no obvious period in the fluctuations. A histogram of the raw open-loop data samples (quantized to 12 bits) showed a series of discrete lines. Closer inspection revealed that the lines were all at quanitization values whose binary code ends with a string of 0's, for example lines at quantization values 1024, 1024+32, 1024+64, 1024+128, etc. Furthermore, each line was paired with a quantization value immediately to its left (i.e. next lowest value) at which there was a deficit in the histogram value. Apparently, the RSSD analog-digital conversion process does not operate uniformly across the entire range of quantization values. Values which end in a string of 0's appear to be significantly more likely to occur than those which end in a string of 1's (the next lowest neighbors). Looking back through our notebooks of USO Test and ORT data, this behavior is not new and is not exhibited at a single station only. We will further investigate the implications of the analog-digital conversion anomaly. I estimated the USO frequency to be 8423152961.21 Hz. The best linear fit to the USO frequency estimates since MGS was brought back from safe mode has a slope of 0.181 Hz/day. The standard deviation of the residual errors to this fit (for recordings since 97/162) is approximately 0.08 Hz. Prior to safe mode, the drift rate of the MGS USO was approximately 0.253 Hz/day. I have estimated the USO Allan deviation at a number of integration times from this ODS. The SNR during the test was approximately 42 dB/Hz. I did not compensate for the spacecraft spin cycle. The measurements confirm that the USO frequency stability has deteriorated since MGS entered the safe mode. The stability during the previous two USO tests (both conducted after the return from safe mode) indicated a deterioration. It was not possible to positively confirm it, however, because both of those tests were conducted at the DSS 25 BWG facility for which we had no other data to compare. The Allan deviation for this test follows: t (sec) AD ------ ---------- 0.4096 1.3630e-12 1.6384 4.0690e-13 3.2768 4.2951e-13 6.5536 4.4167e-13 26.2144 3.6724e-13 The frequency stability is unusual in this test because it does not improve appreciably with integration time. Even in the two prior tests at DSS 25, the Allan deviation was on the order of 1.4e-13 at an integration time of 26 seconds.