PDS_VERSION_ID = PDS3 LABEL_REVISION_NOTE = "2010-08-18 P. McKerracher/M. Reid JHU/APL, Initial version" RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 2010-09-15 END_OBJECT = TEXT END Chandrayaan-1 Mini-SAR Mini-RF Instrument Science Data Archive CALINFO.TXT 24 January 2011 Mini-RF POC Team Johns Hopkins University Applied Physics Laboratory ============================================================================= INTRODUCTION ============================================================================= Chandrayaan-1 (Ch-1) CALIBRATION DATA - SPECIAL DESCRIPTIONS File Name: CALIB/NADIR/FSC_RPD_200901182144_V01.DAT Summary of Data Source: Chandrayaan-1 Jan. 18, 2009, 21:44 UTC, Mini-RF Nadir Pointing towards Lunar Surface Forerunner / Ch-1 Mini-RF, S-Band Calibration Event Description: The Chandrayaan-1 spacecraft rolled until the Mini-RF Antenna was nadir pointing. Mini-RF transmitted an S-Band signal to the lunar surface and received the backscattered RF, for less than 2 minutes. Purpose of Calibration: The purpose of this calibration was to perform a cross channel calibration between the Mini-RF Horizontal and Vertical Receiver channels. Calibration Philosophy: This end-to-end experiment rolled the spacecraft to align the Mini-RF radar antenna in a nadir-pointing orientation towards the Moon. (The magnitude of the roll event was 32.66 degrees.) Under this nadir- pointing condition radar backscattering properties are such that both H and V polarizations retain their relative transmitted amplitude and phase balances in the returned signal, as compared to the transmitted signal; that is, the backscatter in the H and V channels remains statistically independent. This experiment allowed for a comparison of the piecewise Rx and Tx calibration responses with an end-to-end system measurement A complete calibration using only nadir measurements is possible if and only if the radar is hybrid- polarimetric, i.e. transmitting circular polarization, and receiving coherently orthogonal linear polarizations, such as H (Horizontal) and V (Vertical) [1]. Since perfect circular polarization was not guaranteed, the Mini-RF calibration effort included a direct characterization of the transmit and receive portions of the radars via Earth-based resources, so as to remove the assumption of perfect circularity of the transmitted signal from the calibration analysis. See the Chandrayaan-1 Arecibo and GreenBank assisted calibration data for this additional calibration information. A combined analysis of this data set with the End-to-End Arecibo data experiment (Arecibo Radio Telescope transmitted a 2384.15 MHz signal to the Mini-RF instrument) allows the analyst to define the receiver characteristics of the Mini-RF. A combined analysis of this data set with the End-to-End GreenBank data experiment (Green Bank Radio Telescope received data transmitted from the Mini-RF instrument) allows the analyst to define the transmission characteristics of the Mini-RF. Calibration Data Quality: Some of the data is "clipped" with the 8-bit values showing +128 or -127. In addition, some SAR data is truncated. The range gate setting used did not allow capture of the entire reflected pulse; only the initial portion was captured. However, the remaining data is of sufficient quantity to provide the required calibration information. File Name: Jan 30, 2009 Arecibo data 19:17h:CALIB/ARECIBO/FSA_RPD_200901301917_V01.DAT Summary of Data Source: Chandrayaan-1 Jan. 30, 2009, 19:17 UTC, Scan along Mini-RF Antenna Elevation Axis Forerunner Ch-1 Mini-RF S-Band Calibration with Arecibo Radio Telescope (ART) - CCSDS Packet Data Event Description: While pointing towards Arecibo Radio Telescope in Puerto Rico, Mini-RF operated in Rx-Only mode and recorded the ART S-Band signal of 2384.15 MHz. A scan covered a range of -36 deg to +24 deg relative to Mini-RF's boresite center, along Mini-RF's Elevation axis. The S/C scan rate was approximately 0.2 degree/second. Purpose of Calibration: The purpose of this calibration was to characterize the in-flight, system characteristics of Mini-RF's receiver and to confirm beam center pointing of Mini-RF. The on-orbit calibration experiments measured the Mini-RF receive (Rx) and transmit (Tx) characteristics on separate days, using different Earth-based antennas, as the corresponding transmitter or receiver platforms. This data represents a measurement of the Rx characteristics. The Arecibo radio telescope in Puerto Rico (ART) acted as a transmitter to the Mini-RF Rx. In a different experiment, the Green Bank Radio Telescope in West Virginia (GBT) received Mini-RF transmissions. For both, the spacecraft reoriented and slewed, such that the Mini-RF to Earth-antenna orientations varied for the azimuth versus elevation antenna axis cuts. Description of Experiment This description describes the entire sequence of activities on Jan 30, 2009. On this day the team performed two separate scans: the first along Mini-RF's elevation axis, and the second along Mini-RF's azimuth axis. The data in this file represents the first scan. Chronology: On January 30, 2009 at 18:59:26 UTC, an experiment was initiated with the Chandrayaan-1 spacecraft (S/C) to calibrate the gain and phase imbalance of Mini-RF's receiver channels using Arecibo as the calibration source. Data acquisition operations for the experiment ended at 19:49:35 UTC the same day. At 18:59:26 UTC, ART and the ground station at APL acquired the S/C's downlink telemetry carrier (2331 MHz), thereby verifying tracking of the S/C over the period. About 30 seconds later, both stations reported stable track of the S/C. The pointing profile was derived from the Indian Space Research Organisation's (ISRO's) supplied ephemeris. At 19:14:01 UTC, FR was turned on and initiated its boot sequence. It completed that sequence and entered de-activate state at 19:15:49 UTC At 19:16:01 UTC, ART began broadcast of a CW tone at 2384.15 MHz, through a 2 W amplifier, and continued to transmit that signal until 19:50:54 UTC. At the same time, FR was commanded to activate. At 19:17:01 UTC, the S/C began the first of two maneuvers to sweep Mini-RF's antenna beam in its elevation plane, across ART's antenna boresight. This maneuver entailed changing S/C orientation from its standard attitude (moon-viewing (MV) panel facing Lunar nadir, with Mini-RF antenna pointed 32.66 deg off nadir), to a reference position in which the Mini-RF antenna boresight pointed at ART at instant 19:20:01 during the sweep. The S/C scanned in the elevation plane from -36 deg to +24 deg about this reference, at a peak rate of 0.2 deg/s. The scan terminated at 19:23:01, whereupon the S/C began rotation through 90 deg about Mini- RF's antenna boresight to prepare to perform a similar scan along the orthogonal (azimuth) principal plane. At 19:17:43 UTC, the Mini-RF team had planned a command for Mini-RF to buffer spacecraft attitude data and enable programmable telemetry during the period that it recorded data. However, this command was not uploaded due to operator error at ISRO's MOC. About 10 seconds previous to this time, Mini-RF completed activation and entered the standby state. At 19:18:01 UTC, Mini-RF operated in receive-only mode and began sampling data until 19:22:01 UTC. There were 1024 samples per pulse in each of the receiver's linearly polarized channels designated H (horizontal) and V (vertical). At 19:22:17 UTC, Mini-RF initiated a toggle command to stop buffering attitude data and to disable programmable telemetry. The effect was opposite of that intended, and we obtained limited amount of telemetry until Mini-RF was commanded to shut off at 19:22:35 UTC. Three noteworthy pieces of information were obtained from this happenstance. The antenna temperature for this sweep was -23 deg C and the receiver RF_CCA temperature was +36 deg C. The temperature of the MV panel near FR's electronics was nearly +31 deg C. At 19:26:28 UTC, the S/C was issued a series of commands to initialize itself for the second sweep. At 19:41:01 UTC, Mini-RF was turned on and initiated its boot sequence. It completed that sequence and entered de-activate state at 19:42:49 UTC At 19:43:01 UTC, Mini-RF was commanded to activate. At 19:44:01 UTC, the S/C began the second maneuver to sweep Mini-RF's antenna beam in its azimuth plane, across ART's antenna boresight. This maneuver entailed changing S/C orientation from its previous attitude following the end of the previous sweep, to a reference position in which Mini-RF antenna boresight pointed at ART at instant 19:47:01 during the sweep. The S/C scanned in the azimuth plane from -36 deg to +24 deg about this reference, at a peak rate of 0.2 deg/s. The scan terminated at 19:49:21, whereupon the S/C began recovery to its standard attitude. At 19:44:42 UTC, the Mini-RF team had planned a command for Mini-RF to buffer spacecraft attitude data and enable programmable telemetry during the period that it recorded data. However, this command was not uploaded due to operator error as previously described. About 10 seconds previous to this time, FR completed activation and entered the standby state. At 19:45:01 UTC, Mini-RF operated in receive-only mode and began sampling data until 19:49:01 UTC. The sampling conditions were identical to those of the previous sweep. At 19:49:12 UTC, Mini-RF initiated a toggle command to stop buffering attitude data and to disable programmable telemetry. The effect was opposite of that intended, we obtained limited amount of telemetry until Mini-RF was commanded to shut off at 19:49:35 UTC. Three noteworthy pieces of information were obtained from this happenstance. The antenna temperature for this sweep was -25 deg C and the receiver RF_CCA temperature was +38 deg C. The temperature of the MV panel near Mini-RF's electronics was nearly +31 deg C. **************************************************************************** File Name: Jan 30th Arecibo data 19:44h: CALIB/ARECIBO/FSA_RPD_200901301944_V01.DAT Summary of Data Source: Chandrayaan-1 Jan. 30, 2009, 19:44 UTC, Scan along Mini-RF Antenna Azimuth Axis Forerunner Ch-1 Mini-RF S-Band Calibration with Arecibo Radio Telescope (ART) - CCSDS Packet Data Event Description: While pointing towards Arecibo Radio Telescope in Puerto Rico, Mini-RF operated in Rx-Only mode and recorded the ART S-Band signal of 2384.15 MHz. A scan covered a range of -36 deg to +24 deg from Mini-RF's boresite center, along Mini-RF Aximuth axis. The S/C scan rate was approximately 0.2 degree/second. Purpose of Calibration: The purpose of this calibration was to characterize the in-flight, system characteristics of Mini-RF's receiver and to confirm beam center pointing of Mini-RF. The on-orbit calibration experiments measured the Mini-RF receive (Rx) and transmit (Tx) characteristics on separate days, using different Earth-based antennas, as the corresponding transmitter or receiver platforms. This data represents a measurement of the Rx characteristics. The Arecibo radio telescope in Puerto Rico (ART) acted as a transmitter to the Mini-RF Rx. In a different experiment, the Green Bank Radio Telescope in West Virginia (GBT) received Mini-RF transmissions. For both, the spacecraft reoriented and slewed, such that the Mini-RF to Earth-antenna orientations varied for the azimuth versus elevation antenna axis cuts. Description of Experiment This description describes the entire sequence of activities on Jan 30, 2009. On this day the team performed two separate scans: the first along Mini-RF's elevation axis, and the second along Mini-RF's azimuth axis. The data in this file represents the second scan. Chronology: On January 30, 2009 at 18:59:26 UTC, an experiment was initiated with the Chandrayaan-1 spacecraft (S/C) to calibrate the gain and phase imbalance of Mini-RF's receiver channels using Arecibo as the calibration source. Data acquisition operations for the experiment ended at 19:49:35 UTC the same day. At 18:59:26 UTC, ART and the ground station at APL acquired the S/C's downlink telemetry carrier (2331 MHz), thereby verifying tracking of the S/C over the period. About 30 seconds later, both stations reported stable track of the S/C. The pointing profile was derived from the Indian Space Research Organisation's (ISRO's) supplied ephemeris. At 19:14:01 UTC, FR was turned on and initiated its boot sequence. It completed that sequence and entered de-activate state at 19:15:49 UTC At 19:16:01 UTC, ART began broadcast of a CW tone at 2384.15 MHz, through a 2 W amplifier, and continued to transmit that signal until 19:50:54 UTC. At the same time, FR was commanded to activate. At 19:17:01 UTC, the S/C began the first of two maneuvers to sweep Mini-RF's antenna beam in its elevation plane, across ART's antenna boresight. This maneuver entailed changing S/C orientation from its standard attitude (moon-viewing (MV) panel facing Lunar nadir, with Mini-RF antenna pointed 32.66 deg off nadir), to a reference position in which the Mini-RF antenna boresight pointed at ART at instant 19:20:01 during the sweep. The S/C scanned in the elevation plane from -36 deg to +24 deg about this reference, at a peak rate of 0.2 deg/s. The scan terminated at 19:23:01, whereupon the S/C began rotation through 90 deg about Mini- RF's antenna boresight to prepare to perform a similar scan along the orthogonal (azimuth) principal plane. At 19:17:43 UTC, the Mini-RF team had planned a command for Mini-RF to buffer spacecraft attitude data and enable programmable telemetry during the period that it recorded data. However, this command was not uploaded due to operator error at ISRO's MOC. About 10 seconds previous to this time, Mini-RF completed activation and entered the standby state. At 19:18:01 UTC, Mini-RF operated in receive-only mode and began sampling data until 19:22:01 UTC. There were 1024 samples per pulse in each of the receiver's linearly polarized channels designated H (horizontal) and V (vertical). At 19:22:17 UTC, Mini-RF initiated a toggle command to stop buffering attitude data and to disable programmable telemetry. The effect was opposite of that intended, and we obtained limited amount of telemetry until Mini-RF was commanded to shut off at 19:22:35 UTC. Three noteworthy pieces of information were obtained from this happenstance. The antenna temperature for this sweep was -23 deg C and the receiver RF_CCA temperature was +36 deg C. The temperature of the MV panel near FR's electronics was nearly +31 deg C. At 19:26:28 UTC, the S/C was issued a series of commands to initialize itself for the second sweep. At 19:41:01 UTC, Mini-RF was turned on and initiated its boot sequence. It completed that sequence and entered de-activate state at 19:42:49 UTC At 19:43:01 UTC, Mini-RF was commanded to activate. At 19:44:01 UTC, the S/C began the second maneuver to sweep Mini-RF's antenna beam in its azimuth plane, across ART's antenna boresight. This maneuver entailed changing S/C orientation from its previous attitude following the end of the previous sweep, to a reference position in which Mini-RF antenna boresight pointed at ART at instant 19:47:01 during the sweep. The S/C scanned in the azimuth plane from -36 deg to +24 deg about this reference, at a peak rate of 0.2 deg/s. The scan terminated at 19:49:21, whereupon the S/C began recovery to its standard attitude. At 19:44:42 UTC, the Mini-RF team had planned a command for Mini-RF to buffer spacecraft attitude data and enable programmable telemetry during the period that it recorded data. However, this command was not uploaded due to operator error as previously described. About 10 seconds previous to this time, FR completed activation and entered the standby state. At 19:45:01 UTC, Mini-RF operated in receive-only mode and began sampling data until 19:49:01 UTC. The sampling conditions were identical to those of the previous sweep. At 19:49:12 UTC, Mini-RF initiated a toggle command to stop buffering attitude data and to disable programmable telemetry. The effect was opposite of that intended, we obtained limited amount of telemetry until Mini-RF was commanded to shut off at 19:49:35 UTC. Three noteworthy pieces of information were obtained from this happenstance. The antenna temperature for this sweep was -25 deg C and the receiver RF_CCA temperature was +38 deg C. The temperature of the MV panel near Mini-RF's electronics was nearly +31 deg C. ============================================================================= DIRECTORY CONTENTS ============================================================================= The calibration data files (*.DAT) are accompanied by associated metadata (*.TXT) and instrument housekeeping data (*.CSV). The data products have associated detached PDS labels (*.LBL). The files are named based on the orbit number in which the data were collected.