urn:nasa:pds:clementine1_gravity_and_topography:topography_data:gltm2bpr 1.0 1.19.0.0 Product_Observational 2023-02-13 1.0 PDS4 migrated product. Deep Space Program Science Experiment Mission urn:nasa:pds:context:investigation:mission.deep_space_program_science_experiment data_to_investigation Clementine 1 Clementine 1 Host urn:nasa:pds:context:instrument_host:spacecraft.clem1 is_instrument_host LIDAR High-Resolution Imager Instrument urn:nasa:pds:context:instrument:clem1.lidar is_instrument Moon Satellite urn:nasa:pds:context:target:satellite.earth.moon data_to_target gltm2bpr.tab This file contains topographic profiles and related data along each observational pass during which LIDAR laser range data were acquired. The data were created using the final spacecraft orientation and orbital solutions. The laser ranges are believed to be correct, but there may be unresolvable ambiguities due to noise. 0 72548 The GLTM-2B profiles table contains the laser ranges and related data for each orbit profile. Each row in the table contains the date/times, positions of laser bounce points, relative elevations, revolution number, and trigger bins. The (delimited) data require 80 ASCII characters; these are followed by a pad of 2 unspecified ASCII characters, an ASCII carriage-return, and an ASCII line-feed. Carriage-Return Line-Feed 9 0 84 universal time 1 1 ASCII_Date_Time_YMD 23 The date and time of the laser fire, in Universal Time Coordinates (UTC), for that point in the orbit. longitude 2 25 ASCII_Real 9 degree The longitude of the laser bounce point, in IAU body-fixed coordinates. Positive longitude direction is east. latitude 3 35 ASCII_Real 9 degree The latitude of the laser bounce point, in IAU body-fixed coordinates. elevation 4 45 ASCII_Real 8 meter The elevation in meters above a spheroid of radius 1738 km at the equator, with a flattening of 1/3234.93 corresponding to the flattening of the geoid. relative elevation 5 54 ASCII_Real 8 meter The elevation in meters relative to a 1738 km radius sphere. revolution number 6 63 ASCII_Integer 4 The revolution during which data were acquired for that point. The revolutions included are from 20-332. Ranges acquired on calibration passes 8-19 were discarded as too noisy. bin 7 68 ASCII_Integer 2 A number designating whether the data are the result of a trigger before (0), inside (1-4), or after (5) the range window. The lidar electronics triggered on photon pulses continuously, and recorded up to four pulses within a programmable range window. The last trigger before and the first trigger after the range window were also recorded. Usually, but not always, the first trigger within the range window was the valid range. For some laser shots, multiple pulses were detected within the expected time interval for lunar reflections. At most one of these pulses is designated valid in this archive. new bin 8 71 ASCII_Integer 2 Many triggers occurred due to noise in the electronics and could not possibly have resulted from lunar surface reflections. Those triggers that could have resulted from topography within a +/- 12 km distance from the reference lunar spheroid (see elevations, column 4) were assigned bins from 1 to 4. These bins were used as weights in the filtering procedure (Smith et al., The Topography of the Moon from the Clementine LIDAR, submitted to Journal of Geophysical Research, 1995). These weights corresponded to a value of sigma = NEWBIN * (1 km), for each trigger. The filter iteratively estimates the topography, with an a priori covariance function given by cov(R) = (5 km)^2 * exp(-R/170), where R is distance in km between any two points on the Moon. The filter passes ranges within 2.0 sigma of the predicted range. nadir angle 9 74 ASCII_Real 7 degree The angle off nadir, calculated from spacecraft quaternion data using star tracking. A number of passes were intentionally pointed off-nadir in order to cover previously skipped regions, and in some cases spacecraft commands inadvertently resulted in off-nadir pointing. Where quaternion data were missing, the interpolation software generated spurious angles, but the lidar is assumed to be nominally nadir-pointing, as the ranges appear valid. Angles greater than 15 degrees correspond to missing quaternion data. gltm2bpr.lbl 0 PDS3 Original PDS3 label Carriage-Return Line-Feed