PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 2000-04-24 NOTE = "A lookup table that provides the value for the OBSERVATION_CLASSIFICATION keyword in the obs*.tab files." END_OBJECT = TEXT END 1. Overview This document describes the bit contents of the OBSERVATION_CLASSIFICATION keyword, including an explanation for each bit and the code definitions for the bit values. The information in this keyword is primarily based on the data collection command sequences uploaded to TES, and the instrument self-reported activity that is returned with the collected data. For more details of uploaded command sequences per orbit, see the summarized Experimenter's Notebook entries in data/enb.txt. The OBSERVATION_CLASSIFICATION keyword is located in the obs*.tab files and is intended to be used as an index of observation criteria in a "vanilla" data selection command. Table 1 lists the vanilla field names and outlines the organizational structure of the keyword. The remainder of this document provides details for each bit group in the order they appear in the keyword, with the exception of the Numerical Details group which is discussed with the TES Target Type and Command Sequence groups on which it depends. Table 1 - Classification Bit Structure BIT NO. CLASSIFICATION VANILLA FIELD NAME 1-3 MGS Mission Phase Identity MISSION_PHASE 4-7 TES Target Type INTENDED_TARGET 8-11 Command Sequence (Target dependent) TES_SEQUENCE 12,13 Neon Lamp Status NEON_LAMP_STATUS 14 Timing Accuracy TIMING_ACCURACY 15,16 (Reserved for future use) SPARE 17-32 Numerical Details (Sequence dependent) CLASSIFICATION_VALUE 2. MGS Mission Phase Identity The Mission Phase is defined in the MGS Mission Plan (see catalog/mission.cat) and included here in bits 1-3. Note that bit values of 0 or greater than 5 indicate an error has occurred, and the OBSERVATION_CLASSIFICATION keyword should not be used for this observation. BIT CODE DEFINITION 0 = Error 1 = Aerobraking Phase 1 (AB-1) 2 = Science Phasing Orbit 1 (SPO-1) 3 = Science Phasing Orbit 2 (SPO-2) 4 = Aerobraking Phase 2 (AB-2) 5 = Mapping Phase >5 = Error 3. TES Target Type, Command Sequence, and Numerical Details The bits for Target Type (bits 4-7), Command Sequence (bits 8-11), and the Numerical Details (bits 17-32) are organized in a pseudo-tiered structure, with each successive bit group dependent on the information in the previous bit group. There are 9 exclusive Target Groups including "no target", various physical targets, and observational tests for instrument health and data quality related issues. For each Target Group there are 1 to 8 Command Sequences specific to that Target Group (see below). The Numerical Details are signed (+/-) values related to the Command Sequence for selected entries; these values include latitude, timing before or after periapsis, or ANS roll number relative to periapsis. (For more information on spacecraft configuration or ANS motion modes see catalog/host.cat.) In order to access the information stored in these bits, the vanilla command must contain a selection on both the Target Type and Command Sequence, (Numerical Details optional). The following are two examples of a vanilla call selection criteria and their respective results: -select "OBSERVATION_CLASSIFICATION:INTENDED_TARGET 1 1 \ OBSERVATION_CLASSIFICATION:TES_SEQUENCE 3 3" returns surface periapsis nadir observations conducted in the mapping spacecraft configuration -select "OBSERVATION_CLASSIFICATION:INTENDED_TARGET 6 6 \ OBSERVATION_CLASSIFICATION:TES_SEQUENCE 2 2 \ OBSERVATION_CLASSIFICATION:CLASSIFICATION_VALUE +1 +1" returns ANS roll, Mars and space observations collected in mapping mode during the first outbound roll. BIT CODE DEFINITION FORMAT # = TES Target Type # = Command Sequence (Target dependent) Numerical Details included in bits 17-32 BIT CODE DEFINITION 0 = No Target 1 = Surface Target 1 = periapsis nadir looks, aerobrake spacecraft configuration -x down 2 = periapsis nadir looks, aerobrake spacecraft configuration +x down 3 = periapsis nadir looks, mapping spacecraft configuration +z down 4 = surface mosaic (during mapping phase) Latitude in bits 17-32 5 = MOC coincident looks (rollout), SPO1 targets: Viking 1, Viking 2, Pathfinder, Cydonia Region 6 = Emission Phase Function (airmass set) Latitude in bits 17-32 2 = Atmospheric Target 1 = limb set, fore Seconds before/after periapsis in bits 17-32 2 = limb set, aft Seconds before/after periapsis in bits 17-32 3 = halo observation (see data/enb.txt) Seconds before/after periapsis in bits 17-32 3 = Phobos Target 1 = Phobos Data 4 = Deimos Target 1 = Deimos Data 5 = Reference Target 1 = reference look of internal black body 2 = reference look of albedo lamp one 3 = reference look of space 6 = Space and Global Mars Targets 1 = ANS roll contains Mars, sample mode In/outbound roll number relative to periapsis in bits 17-32 2 = ANS roll contains Mars, map mode In/outbound roll number relative to periapsis in bits 17-32 3 = ANS roll contains Mars, contingency mask In/outbound roll number relative to periapsis in bits 17-32 4 = ANS roll contains Mars, pseudo-idle In/outbound roll number relative to periapsis in bits 17-32 5 = ANS roll contains space only, sample mode In/outbound roll number relative to periapsis in bits 17-32 6 = ANS roll contains space only, map mode In/outbound roll number relative to periapsis in bits 17-32 7 = ANS roll contains space only, contingency mask In/outbound roll number relative to periapsis in bits 17-32 8 = ANS roll contains space only, pseudo-idle In/outbound roll number relative to periapsis in bits 17-32 7 = Test Data 1 = Image Motion Compensation (IMC) Test 2 = Background Noise Test 3 = Albedo Calibration Test 4 = Interferogram Test 5 = "Ringing-Data" Test 6 = High Gain Antenna/Solar Panels Noise Test 8 = Less Than Ick 15 1 = Instrument setup period at beginning of each orbit 9 = PROM Data 1 = PROM 4. Neon Lamp Status Bits 12 and 13 describe the status of the neon lamp which affects the ability of the instrument to collect spectral data. Albedo and thermal bolometer observations are not affected by the neon lamp status. BIT CODE DEFINITION 0 = Neon lamp on, spectra collected 1 = Neon lamp off, spectra not collected 5. Timing Accuracy Bit 14 describes observation timing accuracy which is related to the equator crossing broadcast. During all pre-mapping phases (AB-1, SPO-1, SPO-2, AB-2), the equator crossing is supplied by ground command. Any orbits executed between uplinks of the equator crossing contain timing accuracy drifts, which increase in severity with each passing orbit. In mapping, the MGS-PDS supplies the equator crossing broadcast; however, missed broadcasts still occur, resulting in a timing accuracy drift. BIT CODE DEFINITION 0 = most accurate timing, MGS-PDS equator crossing broadcast received 1 = timing drifts present, MGS-PDS equator crossing broadcast not received