Package: slrfield
Welcome to the SLRfield packageThis package is an archive of scientific routines for data processing related to SLR(Satellite Laser Ranging).
Currently, operations on SLR data include:Download CPF(Consolidated Prediction Format) ephemeris files automatically fromCDDIS(Crustal Dynamics Data Information System) orEDC(EUROLAS Data Center);Parse the CPF ephemeris files;Predict the positions of targets in topocentric reference frame, and compute the time of flight for laser pulse;Calculate the position of targets in GCRF;How to InstallOn Linux, macOS and Windows architectures, the binary wheels can be installed using pip by executing one of the following commands:pip install slrfield
pip install slrfield --upgrade # to upgrade a pre-existing installationHow to useDownload the latest CPF ephemeris files at the current momentIf the ephemeris release center is not provided, the CPF ephemeris files are downloaded fromCDDISby default.Download all currently available targets>>>fromslrfieldimportcpf_download>>>cpf_dir_cddis,cpf_files_cddis=cpf_download()# From CDDIS by default;>>>print(cpf_dir,cpf_files)A directory where CPF files are stored, such asCPF/CDDIS/2020-10-02/, will be automatically created.Download a set of targets which are specified by user>>>sat_lists=['ajisai','lageos1','etalon2','jason3']>>>cpf_dir_edc,cpf_files_edc=cpf_download(sat_lists,source='EDC',keep=False)# From EDCNote: by settingkeep = False, the cpf files storage directory will be automaticallyemptiedbeforehand.Download the latest CPF ephemeris files before a specific date and time>>>sat_lists=['starlette','lageos1']>>>date='2017-01-01 11:30:00'>>>cpf_dir_cddis,cpf_files_cddis=cpf_download(sat_lists,date)Parse the CPF ephemeris files and read the dataInformation from the parsed CPF ephemeris files includes the following contents:FormatFormat VersionEphemeris SourceDate and time of ephemeris productionEphemeris Sequence numberTarget nameCOSPAR IDSICNORAD IDStarting date and time of ephemerisEnding date and time of ephemerisTime between table entries (UTC seconds)Target typeReference frameRotational angle typeCenter of mass correctionDirection typeModified Julian DateSecond of DayLeap SecondTime moment in UTCTarget positions in metersParse CPF ephemeris files>>>fromslrfieldimportCPF>>>cpf_data_cddis=CPF.from_files(cpf_dir_cddis)>>>print(cpf_data_cddis.info)Make predictions w.r.t. a siteThe azimuth, altitude, distance of a target w.r.t. a given site, and the time of flight for laser pulse etc. can be easily predicted by calling a methodpred_azalt. The output prediction files named with target names are generated by default.There are two modes for the prediction. If the mode is set togeometric, then the transmitting direction of the laser will coincide with the receiving direction at a certain moment. In this case, the output prediction file will not contain the difference between the receiving direction and the transmitting direction. If the mode is set toapparent, then the transmitting direction of the laser is inconsistent with the receiving direction at a certain moment. In this case, the output prediction file will contain the difference between the receiving direction and the transmitting direction. The default mode is set toapparent.The 10-point(degree 9) Lagrange polynomial interpolation method is used to interpolate the CPF ephemeris.Effects of leap second have been considered in the prediction generation.Coordinates of station can either begeocentric(x, y, z) in meters orgeodetic(lon, lat, height) in degrees and meters. The default coordinates type is set togeodetic.For geodetic(lon, lat, height) site coordinatest_start='2017-01-02 17:06:40't_end='2017-01-03 09:06:40't_increment=0.5# secondstation=[46.877230,7.465222,951.33]# geodetic(lon, lat, height) coordinates in degrees and meters by defaultcpf_data_cddis.pred_azalt(station,t_start,t_end,t_increment)For geocentric(x, y, z) site coordinatest_start='2017-01-02 17:06:40't_end='2017-01-03 09:06:40't_increment=2# secondstation=[4331283.557,567549.902,4633140.353]# geocentric(x, y, z) coordinates in meterscpf_data_cddis.pred_azalt(station,t_start,t_end,t_increment,coord_type='geocentric',mode='geometric')Make predictions in GCRFThe cartesian coordinates of targets in GCRF(Geocentric Celestial Reference Frame) can be easily predicted by calling a methodpred_xyz.t_start='2017-01-02 17:06:40't_end='2017-01-03 09:06:40't_increment=5# secondcpf_data_cddis.pred_xyz(t_start,t_end,t_increment)Change log0.2.1 — jul 16, 2023Added time system for loading/updating the EOP file and Leap Second file from IERS0.2.0 — Feb 24, 2022Added support for calculating the cartesian coordinates of targets in GCRFAdded support for quickly computing the passing-site predictionRemoved the module related to TLE dataRemoved the module related to satellite catalog querying0.1.17 — Nov 04,  2021Fixed the problem of response failure caused by accessing a large amount of data from discos remote server using APIFixed the problem that requested URL's length exceeds the capacity limit of the space-track server.Change the process printing style of query from static to dynamic with colorAdded support for orbital eccentricity in celestrak_query and target_query, including options of filtering and sortingAdded support for output of standard(intrinsic) magnitudes of targets in target_query0.1.14 — Jun 18,  2021Fixed the problem that EOP could not be downloaded normally from IERS.0.1.13 — Jun 05,  2021Now you may inject the NORAD IDs of a large number of targets by an input file such asnoradids.txttotarget_query.0.1.11 — Oct 03,  2020The CDDIS will discontinue anonymous ftp access to its archive in October 2020, therefore, this package implements the transition from ftp to EARTHDATA for downloading CPF files.0.1.9 — Jul 26,  2020Added progress bar for downloading data0.1.5 — Jun 9,  2020Expanded the following functions：Automatically download TLE/3LE data fromSPACETRACKPick out space targets that meets specific demands fromDISCOS(Database and Information System Characterising Objects in Space) andCELESTRAKdatabase by setting a series of parameters, such as mass, shape, RCS(Radar Cross Section), and orbit altitude etc.Calculate one-day prediction and multiple-day visible passes for space targets based on TLE/3LE data0.0.2 — Apr 21,  2020Theslrfieldpackage was released.Next releaseAdd functions to download and parse the CRD(Consolidated Laser Ranging Data Format) observationsReferencePython package for satellite laser ranging file formatsConsolidated Laser Ranging Prediction Format Version 1.01sample codeonILRS