Hayabusa Mission LIght Detection And Ranging instrument (LIDAR) Data Set
========================================================================
                                                                              
Introduction                                                                  
============                                                                  
                                                                              
   This document provides an overview of the Hayabusa LIDAR data set.

   LIDAR is an important onboard instrument to measure the distance
   between the spacecraft and the asteroid. Moreover, LIDAR could be
   determined small scale topgraphy on the surface and the gravity and
   mass of the asteroid by means of measurements of spacecraft locations.
   
   Instrument properties of LIDAR are summarized as follows.

   =====================================================================
      Parameter          Specification
   =====================================================================
      Measured range     50 m ~ 50 km
      Accuracy           +/- 1 m at 50 m
                         +/- 10 m at 50 km
   ---------------------------------------------------------------------
      Pulse rate         1 Hz
      Wavelength         1064 nm
      Pulse energy       8 mJ
      Pulse width        14 nsec
      Spread angle       0.5 mrad (1/e^2)
      Beam angle         1.7 mrad (0.097 deg.)
      Beam diameter      85 m at 50 km, 1.7 m at 1 km
   ---------------------------------------------------------------------
      FOV of receiver    1 mrad
      Receiver           Cassegrain, Phi = 126 mm, SiC
   ---------------------------------------------------------------------
      Mass               3.7 kg
      Electric power     17.0 W (+LD heater max 5W)
   ---------------------------------------------------------------------
      Size               240 mm x 228 mm x 250
      Radiator           240 mm x 300 mm
   =====================================================================


File Formats                                                         
============

   The data files are presented in both the ASCII table form. This allows
   the files to be read by MS-DOS/Windows, Unix, and VMS operating systems.


Data Description                                                   
-----------------------------                                                 

   Hayabusa LIDAR data were downliked by 2 kind of packets, HK and OBS
   with NAVS.

   (1) HK packet (Total number of data: 17,359)
   * House Keeping packet was downloaded every 120 sec or less.
   * HK packet included temperature information on LIDAR.

   (2) OBS packet (Total number of data: 1,663,808)
   * OBS packet was recorded every 1 sec.
   * Part of OBS packets were not downloaded because of limitation of
     communication with the Earth.
   * OBS packet didn't include temperature information.
   * Part of OBS packets during the decent included only ranging data.
     In case of that, 0 values were substituted into other columns and
     the range values have systematic uncertainties, -1.9 m + 3.0 m.

   (3) NAVS packet (Total number of data: 21,155)
   * NAVS packet was used during the decent phase in November 2005.
   * Format of NAVS is same as OBS packet.
   * NAVS packet was combined with OBS packet during the decent phase.
   * Total number of data with OBS packet is 1,684,963.

   LIDAR data could have obtained from 10 September 2005 to 25 November
   2005.