DAFETF NAIF DAF ENCODED TRANSFER FILE 'NAIF/DAF' '2' '6' 'LandmarksSPK ' BEGIN_ARRAY 1 16 'DSS-23 ' '-5E0C89C^8' '5E0C89C^8' '616AF' '18F' '32C8' '8' 16 '-932B32F11268D^3' '-1226F8739F52C8^4' 'E55367D2C2C1A8^3' '-A08C9CD462B718^-A' '39F9E34CB1DE8E^-A' '-21E4CBC66FDCB2^-A' '-932B3A50823AF^3' '-1226F84906220A^4' 'E55366444D488^3' '-A08C9CD462B718^-A' '39F9E34CB1DE8E^-A' '-21E4CBC66FDCB2^-A' '-5E0C89C^8' 'BC19138^8' '1^1' '2^1' END_ARRAY 1 16 TOTAL_ARRAYS 1 ~NAIF/SPC BEGIN COMMENTS~ Placeholder SPK for DSN Station DSS 23 ===================================================================== Original file name: dss_23_placeholder_itrf93_201017.bsp Creation date: 2020-10-17 10:15 Created by: Nat Bachman (NAIF/JPL) Introduction ===================================================================== This file provides low accuracy, estimated geocentric states---position and velocity---as a slowly varying function of time for the DSN station DSS 23. Station DSS 23 is under construction as of the creation date of this kernel. Coordinates used to create this file may be in error by 3m or more. Inputs from Google Earth [sic] were used in combination with other data to derive an estimate of station height. Station position vectors point from the earth's barycenter to the station; the vectors are expressed in the ITRF93 terrestrial reference frame. Station velocities are estimates of the derivative with respect to time of these vectors; in this file, velocity is constant. The station velocity has magnitude on the order of a few cm/year. States obtained from this file are given relative to the terrestrial reference frame ITRF93. Using this kernel ===================================================================== Kernel loading -------------- In order for a SPICE-based program to make use of this kernel, the kernel must be loaded via the SPICE routine FURNSH. If you are running application software created by a third party, see the documentation for that software for instructions on kernel management. This kernel must be loaded *after* the kernels earthstns_itrf93_050714.bsp earthstns_fx_050714.bsp if it is used together with those kernels. See also "Associated frame kernels" and "Associated PCK files" below. Associated PCK files -------------------- This kernel should be used together with a binary Earth PCK file. NAIF produces these kernels on a regular basis; they can be obtained via anonymous ftp from the NAIF server naif.jpl.nasa.gov The PCK is located in the path pub/naif/generic_kernels/pck The file name is of the form earth_000101_yymmdd_yymmdd.bpc The first two dates are the file's start and stop times; the third is the epoch of the last datum in the EOP file: data from this epoch forward are predicted. The file's coverage starts at a fixed date (currently chosen to be 2000 Jan. 1) and extends to the end of the predict region, which has a duration of roughly 3 months. NAIF also provides a low-accuracy, long-term predict binary Earth PCK file. See the path cited above for this file and accompanying documentation. Associated frame kernels ------------------------ The frame kernel having (original) file name dss_23_placeholder_itrf93_201017.tf defines a topocentric reference frame associated with the station covered by this file. That kernel supports computations such as finding the azimuth and elevation of a target as seen from a specified station. The frame kernel earth_topo_050714.tf cannot be loaded concurrently with dss_23_placeholder_itrf93_201017.tf. Data sources ===================================================================== The data provided here are taken from the following sources: Station geodetic longitude and latitude and elevation axis height: email communication from Stephen Slobin (JPL). Values were: longitude: 116 deg 52' 19.676" W latitude: 35 deg 20' 22.395" N Station height relative to reference ellipsoid: derived from Google Earth data, in combination with data for DSS-24: the difference between heights at DSS-23 and DSS-24 was added to the calibrated height of DSS-24. (Use of Google Earth was suggested by Stephen Slobin.) Radii of the reference ellipsoid were taken from the NAIF PCK file pck00010.tpc; the source of these radii was [1]. These radii agree with those of the WGS84 reference ellipsoid at the sub-meter level. Values for the X, Y, Z semi-axis lengths are: 6378.1366 6378.1366 6356.7519 (km) [1] Archinal, B.A., A'Hearn, M.F., Bowell, E., Conrad, A., Consolmagno, G.J., Courtin, R., Fukushima, T., Hestroffer, D., Hilton, J.L., Krasinsky, G.A., Neumann, G., Oberst, J., Seidelmann, P.K., Stooke, P., Tholen, D.J., Thomas, P.C., and Williams, I.P. "Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements: 2009." \begindata SITES += 'DSS-23' DSS-23_FRAME = 'ITRF93' DSS-23_CENTER = 399 DSS-23_IDCODE = 399023 \begintext The epoch below is based on the assumption that coordinate data reflect recent measurements. This epoch likely will be updated when calibrated data are available. \begindata DSS-23_EPOCH = @2020-OCT-16/00:00 DSS-23_BOUNDS = ( @1950-JAN-01/00:00, @2050-JAN-01/00:00 ) DSS-23_XYZ = ( -2354.701211153 -4646.970054123 3669.212578480 ) \begintext By convention the topocentric frame epoch is set to a recent date. Compared to use of the epoch of the location, when the two differ, this provides more accurate topocentric frame orientation for computations performed for epochs near the present date, since the topocentric frame orientation relative to the ITRF93 frame is implemented as a fixed offset (TK) frame. \begindata DSS-23_TOPO_EPOCH = @2020-OCT-16/00:00 DSS-23_UP = 'Z' DSS-23_NORTH = 'X' DSS-23_DXYZ = ( -0.0180 0.0065 -0.0038 ) \begintext ~NAIF/SPC END COMMENTS~