はやぶさ2 LIDAR Level1＆Level2 データプロダクト（暫定バージョン）

概要

説明

This is the provisional product data set, observed by the LIght Detection And Ranging (LIDAR) onboard Hayabusa2.
This dataset contains Level 1 laser link experiment data obtained in 2015 and Level 2 time series topography data of Ryugu obtained between 30 June, 2018 and 7 September, 2018.


Level1 data product: laser link experiment

Level1 data contains the results of a laser link experiment between a laser altimeter called light detection and ranging (LIDAR) aboard Hayabusa2 and ground-based satellite laser ranging stations conducted when the spacecraft was near the Earth before and after the gravity assist operation. For details of the experiment, see Noda et al. (2017), Laser Link Experiment with the Hayabusa2 Laser Altimeter for In-flight Alignment Measurement, Earth, Planets and Space, doi:10.1186/s40623-016-0589-8.


Data files are in csv format with columns below.

Laser link mode

column 1: On board time in UTC (YYYY-MM-DDTHH:MM:SS.SSSSSS) The time when a command of the LIDAR was issued is shown as UTC time for valid data. In the laser link mode, it corresponds to the time when the LIDAR started waiting for the laser pulses from a ground laser station.
column 2: Stop1 timing The LIDAR has a 17-bit counter with frequency of approximately 300 MHz (3.3 ns per bit) for ranging. In the laser link mode, the laser diode is triggered by first laser reception, then after a period of laser excitation, shown as “Start timing”, a laser pulse is emitted from the LIDAR. Stop1 timing shows a raw counter value of the interval between first detected pulse and laser diode trigger time in this mode.
column 3: Stop2 timing In the laser link mode, the LIDAR can receive up to two laser shots from the ground station during 1-sec waiting period. Stop2 timing shows the interval between two received pulses.
column 4: Start timing Start timing shows a raw counter value of the interval between laser diode trigger time and laser emission after laser diode excitation. Therefore, the internal delay in the instrument is expressed as Stop1 timing + Start timing.

Range mode

column 1: On board time in UTC (YYYY-MM-DDTHH:MM:SS.SSSSSS) The time when a command of the LIDAR was issued is shown as UTC time for valid data. In the range mode, this time corresponds to the laser shot time of the LIDAR.
column 2: Receiving power of long-range telescope [mV] The output voltage of APD (Avalanche Photo Diode) of the long-range (far) receiving telescope, converted from receiving power to voltage in mV unit, is shown. In the case of laser link experiment, the gain multiplier of the APD is set to high (M = 100, parameter set = 8), the responsivity (conversion coefficient from receiving power to output voltage) is 500 kV/W.
column 3: Laser energy [mJ] This column shows the energy of laser pulse from the LIDAR in mJ unit.

Request for using this data

When you publish your own work based on the Hayabusa2 LIDAR laser link experiment data, please refer to the following paper(s):


Level2 data product: time series topography

After estimating the spacecraft trajectory with respect to Ryugu, LIDAR ranges are translated into the topography expressed in the asteroid-fixed frame. A paper describing the trajectory correction has been submitted to Icarus (Matsumoto et al., Improving Hayabusa2 trajectory by combining LIDAR data and a shape model, doi:10.1016/j.icarus.2019.113574). Currently available are data obtained between 30 June, 2018 and 7 September, 2018.

The time series topography, together with LIDAR ranges and spacecraft position with respect to Ryugu, are presented in csv files with 11 columns. These can be obtain via https from here.


The files are named as hyb2_ldr_l2_TLM_topo_ts_YYYYMMDD_v1NN.csv.

  • TLM:Telemetry mode: aocsm or hk.
  • YYYYMMDD: Year, month, date.
  • NN: version number used for the internal file sharing purpose with the landing site selection team.
column 1: SHOT_TIME The UTC time of the laser transmission.
column 2: RANGE The distance between spacecraft and asteroid surface calculated from the counter values of laser emission and reception. The accuracy is 0.5 m for AOCSM and 1.0 m for HK. The internal delay time in the LIDAR is taken into account. Unit is in m.
column 3: TOPO_LONGITUDE The longitude of a laser footprint center position in the asteroid-fixed coordinates, converted from the inertial coordinates by using asteroid ephemeris, and axis and phase of the asteroid rotation. Unit is in degree.
column 4: TOPO_LATITUDE The latitude of a laser footprint center position in the asteroid-fixed coordinates, converted from the inertial coordinates by using asteroid ephemeris, and axis and phase of the asteroid rotation. Unit is in degree.
column 5: TOPO_HEIGHT The height of a laser footprint center position with respect to the center of the asteroid in the asteroid-fixed coordinates, converted from the inertial coordinates by using asteroid ephemeris, and axis and phase of the asteroid rotation. Unit is in meter.
column 6: TOPO_X The X component of a laser footprint center position in the asteroid-fixed coordinates, converted from the inertial coordinates by using asteroid ephemeris, and axis and phase of the asteroid rotation. Unit is in meter.
column 7: TOPO_Y The Y component of a laser footprint center position in the asteroid-fixed coordinates, converted from the inertial coordinates by using asteroid ephemeris, and axis and phase of the asteroid rotation. Unit is in meter.
column 8: TOPO_Z The Z component of a laser footprint center position in the asteroid-fixed coordinates, converted from the inertial coordinates by using asteroid ephemeris, and axis and phase of the asteroid rotation. Unit is in meter.
column 9: SC_POS_X The X component of the spacecraft position in the asteroid-fixed coordinates, converted from the inertial coordinates by using asteroid ephemeris, and axis and phase of the asteroid rotation. Unit is in meter.
column 10: SC_POS_Y The Y component of the spacecraft position in the asteroid-fixed coordinates, converted from the inertial coordinates by using asteroid ephemeris, and axis and phase of the asteroid rotation. Unit is in meter.
column 11: SC_POS_Z The Z component of the spacecraft position in the asteroid-fixed coordinates, converted from the inertial coordinates by using asteroid ephemeris, and axis and phase of the asteroid rotation. Unit is in meter.

キーワード

HAYABUSA2 📓📅Light Detection and Ranging (LIDAR) altimeter 📓📅PlanetaryScience 📓📅Asteroid 📓📅(162173) Ryugu 📓📅NearInfrared 📓📅

バージョン

provisional

公開日

2017

時間範囲

from 2015-12-11 to 2015-12-19

from 2018-06-30 to 2018-09-07

識別子

  • タイトル: はやぶさ2 LIDAR Level1＆Level2 データプロダクト（暫定バージョン）
  • ID: darts:hayabusa2-lidar-provisional-data
  • URL: https://darts.isas.jaxa.jp/datasets/darts:hayabusa2-lidar-provisional-data

データ配布

データ構造 (自動生成されたサマリー)
pub/hayabusa2/lidar_bundle/
├── browse/  [not expanded]
└── data/
    ├── Ryugu/
    │   └── l2/
    │       └── hyb2_ldr_l2_[aocsm|hk]_topo_ts_{YYYYMMDD}_v{NNN}.csv
    └── Transfer/
        └── l1b/
            └── hyb2_ldr_l1b_laser_link_exp_aocsm_{YYYYMMDD}_[opt|rng].csv

作成者

  • ISAS > Institute of Space and Astronautical Science (宇宙科学研究所) [ROR: 034gcgw60]

著作権者

  • JAXA > Japan Aerospace Exploration Agency (宇宙航空研究開発機構) [ROR: 059yhyy33]
  • ISAS > Institute of Space and Astronautical Science (宇宙科学研究所) [ROR: 034gcgw60]

ライセンス

参考文献

関連データ

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