Mars Express Bistatic Radar Experiment Operations Plan and Report 01 October 2005 Summary ======= DSN Antenna: 14 Pass: 0853 Orbit: 2202 Orbit Start Time: 2005-10-01T04:12:25 HGA Pointing: Inertial Specular Condition: 2005-10-01T08:34:00 ERT Target: (49.65N, 118.82E, 3381225 m) Incidence/Reflection Angle: 60.57 deg Slant Range: 5649 km Slew Angle: 58.86 deg Doppler (carrier, fd): -60321 Hz Doppler (echo, fr): -56381 Hz Doppler Difference (fdd): -3940 Hz Earth-Mars Distance: 7.840E10 m Experiment Set Up ================= This experiment was conducted using Goldstone's DSS 14. The support team at JPL included Gene Goltz, Danny Kahan, and Dick Simpson. In the NOPE area was Greg Hewitt. Performance Problems ==================== As has been the case on previous experiments at DSS 14 since July, there were problems with the pre-calibration on X-LCP. These were later traced to a typo in the procedure which erroneously connected the X-band ambient load to the X- RCP receiver and then to the X-LCP I/F. During the pre-cal for this experiment, we repeated the noise diode disable command and successfully returned the X-LCP channel to its proper configuration before the pre-cal was completed. The NOPE requested a DR from the station (G106121). Also as on recent DSS 14 observations, the S-LCP channel seemed less stable than the other three in the sense that ADC amplitudes jumped around when constant levels were expected and it was harder to detect changes in noise diode status. During analysis of the data it became apparent that there were serious interference problems on the X-RCP channel during this experiment. Although the ground antenna elevation was more than 50 degrees (and increasing) throughout the BSR observation, the noise level increased by 5 percent at about 08:24 and by another 20 percent at about 08:29. There were also a number of spurs starting at about 08:29, some moving quickly and others not. A check of our MGS radio occultation data collection showed that MGS emerged from occultation at about 08:24:27 and its telemetry was turned on at about 08:28:41, explaining both changes in the noise level. Since the noise was "normal" during the interval 08:14-08:28, we can use that as our reference for determining X-RCP system temperature. Using 1024-point power spectra we have identified a frequency window that can serve as a noise power reference during the time when we were collecting surface echoes -- bins 809:908 (19714-22133 Hz) are relatively stable (albeit elevated by about 25 percent) during the time interval 08:28:15-08:41:30. The surface echo power can be measured with some confidence during 08:31:30-08:36:00 in a sliding window that starts at bins 390:524 and ends at bins 533:667. The surface echo overlaps the residual carrier during approximately 08:30-08:31. There is no hint of interference in the X-LCP channel or in either of the S-band channels. There is a 28 Hz increase in the S-Band carrier frequency at 08:39:45. Data Acquisition ================ The set up period began at 04:00. DSS 14 announced that it was ready to begin the pre-calibrations about 10 minutes later. Except for the X-LCP noise diode problem and the S-LCP stability problem noted above, the pre-calibration was nominal. RSRs were configured as in Table 1: Table 1 --------------------------------------------- RSR Channel Mode ATT FGAIN Operator dB ----- ------- ---- ---- ----- --------------- RSR3A S-LCP 1-W auto 60 Kahan RSR3B X-LCP 1-W auto 60 Kahan RSR2A S-RCP 1-W auto 68 Goltz RSR2B X-RCP 1-W auto 60 Goltz RSR subchannels (SCHAN) were defined as follows: Table 2 --------------------------------------------------------------------- Subchannel Sample Rate Comments ---------- ----------- --------------------------------------------- 1 1 ksps 2 8 ksps 3 25 ksps Primary recording bandwidth 4 100 ksps Backup recording Table 3 lists ADC amplitude levels read from RSR displays during the experiment. Where available, signal-to-noise ratios, frequency offsets, and other measurements are also listed. Times are in UTC read from a wall clock and may not reflect actual times when configurations changed. "Steps" are as defined in the briefing message. Acronyms and abbreviations are explained after Table 3. Table 3 ------------------------------------------------------------------------------ TIME (ERT) RSR3A RSR3B RSR2A RSR2B COMMENTS 2005-10-01 S-LCP X-LCP S-RCP X-RCP ADC ADC ADC ADC (dB) (dB) (dB) (dB) ---------- ------ ------ ------ ------ --------------------------------------- End-to-End Configuration Check 04:10 -9.3 -10.3 -9.9 -10.1 Step 01: DSS 14 ready to proceed; RSSG sets ATT usding AUTO feature 04:13 MEX MOC and NOPE agree on no telemetry 04:15 -2.7 -0.3 -0.9 -0.0 Steps 02, 03, and 04 04:17 RSSG requests return to Step 01 04:19 -10.6 -10.2 -9.9 -10.1 Step 01: All channels to sky 04:21 -12.4 -0.3 -9.9 -0.1 Step 02: X-band to AMB 04:22 -2.6 -0.3 -9.8 -0.0 Step 03: S-LCP to AMB NOPE reminds DSS 14 to type OD's as in briefing message and not to use time stacking. 04:24 -2.2 -0.3 -0.4 -0.1 Step 04: S-RCP to AMB Pre-Calibration 04:25 Ambient load temperatures: S1 = 18.19C S2 = 23.62C X1 = 14.81C Weather conditions: T = 32C P = 901 mbar H = 13% Sky partly cloudy 04:25 -9.7 -10.1 -10.4 -10.0 Reset all ATTEN using auto feature 21.5 16.0 15.5 23.0 ATTEN settings 04:30:01 All RSR's recording 25 kHz 04:33 -10.0 -10.0 -10.3 -10.0 Step 05: Configure ND controllers 04:36 -9.7 -9.9 -10.2 -9.8 Step 06: XR ND on 04:41 -9.7 -22.1 -10.3 -20.1 Step 07: X-band to sky 04:47 -9.6 -22.2 -10.3 -22.6 Step 08: XR ND off 04:48 -9.7 -20.8 -10.3 -22.6 Spontaneous X-LCP change; DSS 14 confirms SNT D 04:51 -9.6 -19.8 -10.2 -22.6 Step 09: XL ND on DSS 14 confirms 12.5K ND selected 04:56 -9.7 -10.6 -10.2 -9.9 Step 10: X-band to AMB (XL is too low) Ambient load temperatures: S1 = 18.00C S2 = 23.25C X1 = 15.12C 05:01 -9.8 -10.5 -10.3 -9.9 Step 11: XL ND off (no change in XL) 05:06 -9.6 -19.6 -10.1 -22.6 Step 12: X-band to sky (XL is too high) 05:11 -9.6 -22.1 -10.2 -22.4 Repeat Step 11: X-LCP ND now off 05:16 -9.7 -21.9 -10.0 -22.7 Step 13: SR ND on 05:21 -9.7 -21.9 -19.5 -22.6 Step 14: SR to sky 05:27 -9.7 -22.0 -22.0 -22.5 Step 15: SR ND off DSS 14 confirms 12.5 ND selected 05:32 -9.4 -21.9 -22.1 -22.6 Step 16: SL ND on 05:37 -15.0 -22.0 -22.1 -22.7 Step 17: SL to sky 05:38 -18.8 -21.9 -22.1 -22.7 Unexpected change in S-LCP level 05:42 -20.2 -22.0 -22.1 -22.6 Step 18: SL ND off Ambient load temperatures: S1 = 18.94C S2 = 23.19C X1 = 17.00C 05:45 Stop RSR 25 kHz recording Spacecraft Calibration (BCAL #1) and Slew #1 05:59 -19.3 X-RCP signal acquired (ADC amplitude, dB) 69.0 Px/No -2302 Offset from center (Hz) 06:41 DSS 14 reports X-band carrier in lock 07:05 -12.7 -21.0 -21.7 ? X-band 3-way; S-LCP is very high 07:09 -10.0 -21.0 -21.6 -19.4 X-band, 1-way (ADC ampl, dB) 69.0 Px/No (dB) -2669 Offset from center (Hz) 07:10 Begin RSR 25 kHz recording 07:11 -18.0 -21.0 -21.7 -19.5 S-band in lock 29 42 56 69 Px/No (dB) -1280 -2697 -1279 -2695 Offset (Hz) 07:23 -17.4 -21.0 -21,5 -19.4 ADC amplitude (dB) 29 43 56 69 Px/No (dB) -1325 -2867 -1332 -2888 Offset (Hz) 07:28 -17.4 -21.0 -21.2 -19.3 ADC amplitude (dB) 29 50 56 76 Px/No (dB) -1367 -3017 -1361 -2998 Offset (Hz) Mini-Cal #1 07:43 DSS 14 confirms DTT 01 and DTT 02 configurations for MiniCal #1 07:46 Begin Slew #1 07:47 -13.5 -21.0 -21.5 -19.5 Step 01: XR ND on (SL high) 07:50 -16.8 -21.0 -19.1 -21.4 Step 02: XR ND off, SR ND on 30 38 24 39 Px/No (dB) -1447 -3310 -1447 -3305 Offset (Hz) 07:53 -17.6 -19.1 -21.3 -21.4 Step 03: SR ND off, XL ND on 17 24 24 37 Px/No (dB) -2486 -3284 -1444 -3290 Offset (Hz) 07:56 -16.0 -21.0 -21.2 -21.6 Step 04: XL ND off, SL ND on 18 25 11 23 Px/No -1400 -3260 -7920 -3250 Offset (Hz) 07:59 -17.0 -21.1 -21.7 -21.9 Step 05: SL ND off 20 25 13 21 Px/No (dB) -1428 -3240 10171 -3238 Offset (Hz) 08:03 End Slew #1 Bistatic Radar Activities 08:04 Begin RSR SCHAN=4 recording (100 kHz) 08:28:30 First echoes visible in X-LCP 08:30 Echoes in all channels 08:32 -19.2 -21.0 -21.9 -21.2 Echo, multiple peaks at X-band 27 37 28 37 Px/No (dB) -600 -650 -610 -400 Offset (Hz) 08:34 -16.8 -20.9 -22.0 -21.2 Echo, 2 kHz wide at X-band 26 39 28 39 Px/No (dB) -462 434 -400 550 Offset (Hz) 08:35 -18.0 -21.0 -22.0 -21.1 Echo 28 40 27 38 Px/No (dB) -340 1163 -231 1355 Offset (Hz) 08:36 -18.9 -21.1 -22.1 -21.1 Echo fading, 2 peaks 25 20 26 28 Px/No (dB) -251 2500 -27 3200 Offset (Hz) 08:41 X-band echo has 2 peaks at +3 and +7 kHz 08:45 Echoes gone 08:47 -16.8 -21.1 -22.0 -20.9 Carrier ADC amplitude (dB) 16 28 18 Px/No -1356 -2970 -2966 Offset (Hz) 09:04 End RSR 100 kHz recording Mini-Cal #2, Slew #2, and BCAL #2 09:04 -19.1 -21.6 -22.0 -19.2 Step 01: XR ND on 09:04:11 Begin Slew #2 09:06 Interfering signal at upper edge of XR spectrum moving at -5 kHz per minute 09:07 -19.9 -21.0 -19.7 -20.8 Step 02: XR ND off, SR ND on 09:08 Interference abruptly disappears at center of XR passband 09:10 -19.5 -18.9 -22.1 -20.9 Step 03: SR ND off, XL ND on 09:13 -17.9 -21.0 -21.9 -20.8 Step 04: XL ND off, SL ND on 09:16 -19.1 -21.0 -22.0 -20.8 Step 05: SL ND off 29 41 33 44 Carrier Px/No (dB) -1327 -2875 -1329 -2530 Carrier offiset (Hz) 09:22 -19.8 -21.0 -22.0 -19.0 Slew #2 complete 32 46 56 77 Carrier Px/No (dB)P -1248 -2574 -1247 -2575 Carrier offset (Hz) 10:06 -20.0 -21.0 -22.0 -19.8 S-band TX off 77 Carrier Px/No (dB) -2529 Carrier offset (Hz) 10:08 -22.1 -19.7 X-band telemetry on 70 Carrier Px/No (dB) -2524 Carrier offset (Hz) Post-Calibration 10:16 DSS 14 going to zenith 10:25 -9.6 -9.4 -10.3 -9.9 Step 01: All channels to AMB at zenith Ambient load temperatures: S1 = 19.31C S2 = 22.31C X1 = 17.94C 10:27 -9.6 -9.5 -10.3 -9.7 Step 02: XR ND on 10:30 -9.5 -9.4 -10.0 -10.0 Step 03: XR ND off, SR ND on 10:33 -9.5 -9.2 -10.3 -10.0 Step 04: SR ND off, XL ND on 10:36 -9.4 -9.4 -10.4 -10.0 Step 05: XL ND off, SL ND on 10:39 -18.0 -21.6 -22.1 -22.6 Step 06: All to sky 10:42 -19.8 -19.3 -22.0 -22.5 Step 07: SL ND off, XL ND on 10:45 -19.2 -21.7 -19.5 -22.6 Step 08: XL ND off, SR ND on 10:48 -19.1 -21.6 -22.0 -20.1 Step 09: SR ND off, XR ND on 10:51 -17.9 -21.6 -22.1 -22.6 Step 10: XR ND off Ambient load temperatures: S1 = 19.25C S2 = 22.31C X1 = 17.69C Weather conditions: T = 19.6C P = 899.8 mbar H = 20.0% Sky clear, winds calm 10:55 End of track Stop RSR recording (SCHAN=3) AMB = ambient load BOT = Beginning of Track CONSCAN = conical scan tracking CW = continuous wave (carrier only) EOT = End of Track FRO = frequency offset HGA = high-gain antenna LOS = loss of signal ND = noise diode No = noise power Pc = carrier power S1 = ambient load for S-RCP S2 = ambient load for S-LCP SL = S-LCP SR = S-RCP TLM = telemetry X1 = Ambient load for both X-band channels XL = X-LCP XR = X-RCP Dick Simpson Original: 2005-10-01 Edits: 2005-12-29 Added notes on X-RCP interference: 2006-01-17