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CHRONOS for MER How to use it. Boris Semenov 9/15/2003. CHRONOS Overview. CHRONOS is a “universal” SPICE-based time conversion tool Provides conversion between several time systems -- UTC, ET, SCLK, LST -- and several types within each system -- ERT, ETT, LTST, etc.
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CHRONOS for MERHow to use it Boris Semenov 9/15/2003
CHRONOS Overview • CHRONOS is a “universal” SPICE-based time conversion tool • Provides conversion between several time systems -- UTC, ET, SCLK, LST -- and several types within each system -- ERT, ETT, LTST, etc. • CHRONOS is available to MER in two forms • As a command-line tool, run via a set of provided aliases • Via a Web interface (this uses the command line tool) • CHRONOS uses a number of SPICE kernels • These are delivered to OSS by NAIF • NAIF also creates and maintains a setup file required for CHRONOS to run • Setup file specifies all kernels that need to be loaded by CHRONOS and provides additional startup information • A custom setup file will be provided for each activity -- flight and PORTs -- for each rover • CHRONOS has been officially delivered to MER and installed on all MER FLTOPS workstations under /msop/naif/exe/chronos. NAIF
CHRONOS Aliases - Overview • Aliases provided for running CHRONOS on MER FLTOPS workstations: • An extensive set of commands can be typed directly on the shell command line to perform various time conversions applicable to MER-A (*.a aliases) or MER-B (*.b aliases) • These are made available for a given activity by running “source” on a single setup file specific to that activity, containing definitions for all aliases and a few environment variables • The setup files used in the aliases point to the MER SPICE data located in the MER Surface OSS • Commands for conversion between primary time systems (LSTA, LTST, SCET, ERT, SCLK): FROM\TO | lsta ltst scet ert sclk ------------------------------------------------------------------------- lsta | - lsta2ltst.a lsta2scet.a lsta2ert.a lsta2sclk.a ltst | ltst2lsta.a - ltst2scet.a ltst2ert.a ltst2sclk.a scet | scet2lsta.a scet2ltst.a - scet2ert.a scet2sclk.a ert | ert2lsta.a ert2ltst.a ert2scet.a - ert2sclk.a sclk | sclk2lsta.a sclk2ltst.a sclk2scet.a sclk2ert.a - where the time systems are: lsta -- MER-A Hybrid Local Solar Time ltst -- MER-A Local True Solar Time scet -- UTC Spacecraft Event Time ert -- UTC Earth Receive Time sclk -- MER-A on-board clock • Commands for selected auxiliary time conversions (ETT, ET, DOY, SCLK/HEX, Ls, LT, PST): scet2ett.a ett2scet.a scet2et.a et2scet.a scet2doy.a doy2scet.a sclk2hex.a hex2sclk.a scet2lt.a scet2lsun.a scet2pst.a scet2pdt.a NAIF
CHRONOS Aliases - PORT-4/5 Example Verify that “tcsh” is the shell you are using; if not, run “tcsh”: % echo $shell % tcsh “Source” CHRONOS aliases file for PORT-4/5: % source /gds/mer/setup/naif/aliases.mer2_port4_5 Convert UTC/SCET to SCLK: % scet2sclk.a 2004 JAN 5 12:00 1/0126576100.080 Convert LSTA to UTC/SCET: % lsta2scet.a SOL 2 12:00 2004-01-05 02:35:37.682 Convert LSTA to LTST: % lsta2ltst.a SOL 2 00:00 SOL 1 23:50:00 Get more information by looking at the aliases “cheat-sheet”: % more /oss/mera/port4_5/sstb/surface/strategic/ref/naif/misc/chronos/ doc/aliases_cheatsheet_mer2a.txt NAIF
Web CHRONOS - Overview • Web CHRONOS for MER: • A simple Web tool performing various time conversions applicable to MER • Activity is selected by picking it up from the “Spacecraft” menu; • For example, MER2_EP55E3_PORT_4_5 should be selected for PORT-4/5 • Uses the CHRONOS command-line utility program and uses the same MER SPICE data, but runs on the NAIF server (naif.jpl.nasa.gov) outside the FLTOPS firewall • MER Web CHRONOS URL http://naif.jpl.nasa.gov/mertime.html • By selecting the “from” time system and type combination in the From menus and the “to” time system and type combination in the To menus, typing the input time in the Input Time field and clicking the Convert button, one can convert time between the following time systems/types: UTC -- types: SCET, ERT, ETT, LT ET -- types: SCET, ERT, ETT, LT, SECONDS SCLK -- types: SCLK, HEX, TICKS LST -- types: LTST, HLST, LSUN • Important notes: • The approximate (hybrid) Local Solar Times for MER-A (LSTA) and MER-B (LSTB) can be selected by picking the LST/HLST system/type combination in the From and To menus • This Web interface does *NOT* work as expected using Netscape on Mac/OSX due to flawed JavaScript implementation in Netscape NAIF