Mars Express Bistatic Radar Experiment Operations Plan and Report 20 April 2012 Summary ======= DSN Antenna: 63 Orbit: 10578 Orbit Start Time: 2012-04-20T20:24:52 HGA Pointing: Specular Start Gale/MSL End -------- ---------- -------- Specular Condition (ERT): 22:31 10:41 23:59 Target Latitude (deg N): 20.03 -4.94 -47.62 Longitude (deg E): 146.53 136.56 234.82 Rp (km): 3394. 3394. 3394. Incidence/Reflection Angle (deg): 53.42 62.59 84.43 Slant Range (km): 8124. 5183. 1275. Slew Angle (deg): 73.16 54.83 11.14 Doppler (carrier, fd; Hz): -13590. -9217. 30497. Doppler (echo, fr; Hz): 23669. 30357. 30645. Doppler Difference (fdd; Hz): -37260. -39574. 1085. Earth-Mars Distance (m): 1.299E+11 1.299E+11 1.299E+11 Experiment Set Up ================= This experiment was conducted using the Madrid DSS 63. Danny Kahan and Gene Goltz were in the Radio Science Support Area (RSSA) at JPL. Dick Simpson monitored by telephone from Stanford. Performance Problems and Notes ============================== There were no significant problems before, during, or after the experiment. Echoes were seen during real time in both S- and X-Band and on both polarizations. In order to characterize the receiving system better, we stepped through some FGAIN and ATT settings after the pre-cal and again after the post-cal. These noise data will be studied for better understanding of where the post-antenna noise sources lie and how the FGAIN and ATT settings affect their appearance in the data. The RSRs continued to record data through these tests, so there is no gap between the pre-cal and tracking data for this experiment. Danny Kahan noticed that X-RCP was clipping when the spacecraft antenna was pointed toward Earth and telemetry was turned off; he increased the X-RCP FGAIN setting to 70 until the beginning of SLEW #1. Data Acquisition ================ RSRs were configured as in Table 1. Table 1 ----------------------------------------------------- RSR Channel Mode ATT FGAIN Operator dB ------ ------- ---- ---- ----- ---------------------- RSR1A S-LCP 1-W auto 60 UNK RSR1B X-LCP 1-W auto 60 UNK RSR2A S-RCP 1-W auto 60 UNK RSR2B X-RCP 1-W auto 65-70 UNK RSR subchannels (SCHAN) were defined as follows: Table 2 ---------------------------------------------------------------------- Subchannel Sample Rate Comments ---------- ----------- --------------------------------------------- 1 2 ksps Occultation bandwidth (not recorded for BSR) 2 8 ksps Occultation backup (not recorded for BSR) 3 25 ksps Primary recording bandwidth 4 100 ksps Backup recording Table 3 lists ADC amplitude levels read from RSR displays during the experiment. Times are in UTC and should be considered approximate. Steps are as defined in the briefing message. RSR ATT settings are in units proportional to dB. Acronyms and abbreviations are explained after Table 3. Table 3 ----------------------------------------------------------------------------- Activity Time Step # S-LCP X-LCP S-RCP X-RCP Notes / Comments 2012/111 RSR1A RSR1B RSR2A RSR2B -------- ----- --------- ----- ----- ----- ----- ------------------------ Set-up 19:15 FGAIN 60 60 60 65 FGAIN settings (dB) Pre-Cal 19:56 1 -7.7 -15.9 -12.8 -9.2 ADC amplitudes (dB) 20:00 att auto -9.8 -10.2 -9.8 -9.6 Auto reset attenuators 22.5 18.0 15.5 25.0 Attenuator settings (dB) 20:02 2 -9.8 -0.3 -9.9 -0.4 X-Band to ambient load 20:03 3 -0.6 -0.5 -9.9 -0.4 S-LCP to ambient load 20:04 4 -0.7 -0.4 -1.0 -0.4 S-RCP to ambient load 20:05 att auto -8.0 -9.8 -9.9 -5.0 Auto reset attenuators 31.5 29.5 26.0 31.5 Attenuator settings (dB) Ambient load phys temps: S1=19.69C S2=20.75C X1=16.38C Local weather: T=14.1C H=55.0 percent sky=partly cloudy 20:08 rec 3 e Begin 25 kHz recording 20:08 5 -8.0 -9.9 -9.8 -4.9 ADC amplitudes (dB) 20:13 6 -8.0 -9.8 -9.9 -4.9 X-RCP ND ON 20:18 7 -8.0 -21.6 -9.9 -15.4 X-Band to sky 20:23 8 -7.9 -21.7 -9.7 -17.2 X-RCP ND OFF 20:28 9 -8.0 -19.3 9.8 -17.3 X-LCP ND ON Confirm 12.5K ND 20:33 10 -8.0 -9.6 -9.8 -5.1 X-Band to ambient load Ambient load phys temps: S1=19.69C S2=20.56C X1=16.12C 20:38 11 -8.0 -9.9 -9.8 -5.1 X-LCP ND OFF 29:43 12 -8.0 -21.7 -9.9 -17.2 X-Band to sky 20:48 13 -8.0 -21.7 -9.7 -17.3 S-RCP ND ON 20:53 14 -8.0 -21.7 -19.4 -17.2 S-RCP to sky 20:58 15 -8.0 -21.7 -21.2 -17.3 S-RCP ND OFF Confirm 12.5K ND 21:03 16 -7.7 -21.7 -21.2 -17.2 S-LCP ND ON 21:08 17 -16.6 -21.7 -21.2 -17.2 S-LCP to sky 21:13 18 -18.8 -21.7 -21.3 -17.2 S-LCP ND OFF Confirm 12.5K ND Ambient load phys temps: S1=19.56C S2=20.38C end X1=15.69C ATT test 21:18 FGAIN 55 55 55 55 Reset FGAIN 21:21 ATT -13.8 -16.6 -16.3 -12.0 Manual ATT reset 26.5 24.5 21.0 26.5 Attenuator settings (dB) 21:24 FGAIN 60 60 60 65 Restore FGAIN settings 21:27 ATT -18.8 -21.6 -21.3 -17.2 Manual ATT restore 31.5 29.5 26.0 31.5 Attenuator settings (dB) end 21:30 Move DSS 63 to point BOT 21:45 -18.7 -21.4 -21.3 -12.3 ADC amplitudes (dB) AOS 21:53 X-AOS, S-AOS, TLM off 22:00 -18.8 -21.3 -21.3 -15.6 DSS 63 to Mars pointing 22:08 sfro 3/SX +4k +31k +4k +31k SCHAN3 RSR offsets (Hz) sfro 4/X +20k +20k SCHAN4 RSR offsets (Hz) MINICAL1 22:13 1 -18.7 -21.2 -21.2 -11.8 XR ND ON Confirm 12.5K ND 22:16 2 -18.8 -21.4 -19.4 -12.5 XR ND OFF, SR ND ON 22:19 3 -18.8 -19.2 -21.2 -12.4 SR ND OFF, XL ND ON 22:22 4 -16.6 -21.2 -21.2 -12.3 XL ND OFF, SL ND ON 22:25 5 -18.8 -21.3 -21.2 -12.2 SL ND OFF END 22:28 end -18.6 -21.3 -21.2 -12.2 ADC amplitudes (dB) BSR 22:31 rec 4 e Begin 100 kHz recording 23:26 sfro 3/X +24k +24k SCHAN3 RSR offsets (Hz) 23:34 sfro 3/X +17k +17k SCHAN3 RSR offsets (Hz) 23:39 sfro 3/X +11k +11k SCHAN3 RSR offsets (Hz) 23:44 sfro 3/X +4k +4k SCHAN3 RSR offsets (Hz) 23:49 sfro 3/X -2k -2k SCHAN3 RSR offsets (Hz) 23:55 sfro 3/X -6k -6k SCHAN3 RSR offsets (Hz) 23:59 rec 4 d -18.4 -21.0 -20.9 -16.3 End 100 kHz recording END BSR sfro 3/SX +60k +60k +60k +60k SCHAN3 RSR offsets (Hz) MINICAL2 00:03 1 -18.7 -21.1 -20.9 -11.6 XR ND ON Confirm 12.5K ND 00:06 2 -18.3 -20.9 -19.2 -12.2 XR ND OFF, SR ND ON 00:09 3 -18.4 -18.9 -20.9 -11.7 SR ND OFF, XL ND ON 00:12 4 -16.4 -21.0 -20.9 -11.7 XL ND OFF, SL ND ON 00:15 5 -18.5 -20.8 -20.9 -11.7 SL ND OFF END 00:18 end -18.4 -20.9 -20.8 -11.8 DSS 63 to s/c pointing sfro 3/SX 0 0 0 0 SCHAN3 RSR offsets (Hz) EOT 00:21 -18.4 -20.8 -20.8 -11.7 ADC amplitudes (dB) -16.3 DSS 63 to zenith PostCal 00:26 1 -7.8 -9.6 -9.9 -5.0 All to ambient loads Ambient load phys temps: S1=19.69C S2=18.81C X1=16.19C 00:30 2 -7.9 -9.8 -10.1 -4.8 XR ND ON 00:33 3 -7.8 -9.8 -9.8 -4.9 XR ND OFF, SR ND ON 00:36 4 -7.9 -9.6 -10.0 -5.0 SR ND OFF, XL ND ON 00:39 5 -7.7 -9.8 -9.9 -5.0 XL ND OFF, SL ND ON 00:42 6 -16.6 -21.6 -21.3 -17.0 All to sky 00:45 7 -18.8 -19.3 -21.2 -17.1 SL ND OFF, XL ND ON 00:48 8 -18.8 -21.5 -19.5 -17.0 XL ND OFF, SR ND ON 00:51 9 -18.7 -21.7 -21.3 -15.5 SR ND OFF, XR ND ON 00:54 10 -18.9 -21.7 -21.2 -17.0 XR ND OFF Ambient load phys temps: S1=19.44C S2=18.81C X1=16.12C Local weather: T=11.2C H=65.6 percent END sky=partly cloudy ATT Test 01:00 FGAIN 55 55 55 55 Reset FGAIN 01:05 ATT -13.7 -16.4 -16.2 -11.8 Manual ATT reset 26.5 24.5 21.0 26.5 Attenuator settings (dB) 01:10 FGAIN 60 60 60 65 Restore FGAIN 01:15 ATT -18.8 -21.5 -21.2 -17.0 Manual ATT restore 31.5 29.5 26.0 31.5 Attenuator settings (dB) EOA 01:20 rec 3 d -18.7 -21.6 -21.2 -17.0 End 25 kHz recording AMB = ambient load BOT = Beginning of Track BW = bandwidth C = Celsius CNR = Carrier to noise ratio CONSCAN = conical scan tracking CW = continuous wave (carrier only) EOA = End of activity EOT = End of Track FRO = frequency offset HGA = high-gain antenna k = kilo, thousand K = Kelvin LOS = loss of signal ND = noise diode No = noise power NOP = Network Operations Plan occn = occultation Pc = carrier power rcvr = receiver S1 = ambient load for S-RCP S2 = ambient load for S-LCP s/c = spacecraft SKY = receiver looking a sky SL = S-LCP SNR = Signal to noise ratio SR = S-RCP TLM = telemetry X1 = Ambient load for both X-band channels XL = X-LCP XR = X-RCP Post Analysis Summary Results appear pretty nominal. On both S and X there is a Brewster angle transition at about 23:15, other changes mostly show up in all four channels at once, RCP increases until almost the end when it drops slightly as incidence angle starts to decrease again, LCP starts to drop after 23:20 and plunges after 23:38 (the S-LCP echo is lost in noise after about 23:45). Dielectric constant at S-Band is larger than at X-Band until about 23:15 and is less than X-Band dielectric constant over 23:15-23:45. Noise power density increases approximately linearly throughout the experiment except that it increases slightly faster in X-RCP after 23:30; the difference from linear is probably no more than 5 percent, however. Dick Simpson Original: 2012-04-21 Corrected typos: 2013-04-04 Added Post-Analysis Summary: 2013-06-17 Minor edits for bad characters: 2013-07-08