# File orbitco.txt, version 1.1, released 97/07/04 at 08:07:54 #HISTORY: # 970703 GIL initial version Subj: GBES orbitco Users guide Vers: DRAFT From: Glen Langston Date: 97 July 3 This document describes GBES offline program "orbitco" for creating an orbit file from a JPL satellite trajectory prediction. The program calculates the satellite uplink and downlink range and range rate as a function of time. The satellite azimuth and elevation are also calculated. orbitco ======= The orbitco program takes as input start and stop times, satellite trajectory file, and satellite ID number. The program prompts the user for these values if they are not supplied. For VSOP tracking, orbitco is usually run from the script "orbit.vsop" which sets the appropriate input values. The script is run by simply typing % ~ovlbi/bin/orbit.vsop The input trajectory is assumed to be in the ~ftp/ovlbi/in directory and the latest file with ".bsp" extension is processed into an orbit file. The output file is placed in the directory ~ovlbi/in. Output ====== The program first prints out the input settings, then summarizes the contents of the trajectory file. As the program executes, the transformations from date to J2000 coordiantes are printed at regular intervals. Below is the beginning of the orbit.vsop output to the terminal: orbit.vsop: usage orbit.vsop where JPL NAIF binary SPK file name and is the first date of the file to convert The latest NAIF files in ~ftp/ovlbi/in are: -rw-rw-r-- 1 ovlbi 685056 Jul 3 09:13 970702-970710-p.bsp -rw-r--r-- 1 ovlbi 702464 Jun 30 19:02 970630-970708-p.bsp -rw-r--r-- 1 ovlbi 691200 Jun 26 19:02 970626-970704-p.bsp -rw-r--r-- 1 ovlbi 606208 Jun 25 19:02 970625-970702-p.bsp -rw-r--r-- 1 ovlbi 688128 Jun 23 16:07 970623-970701-p.bsp Setting defaults InFile = /s3/ftp/ovlbi/in/970702-970710-p.bsp Start, stop dates: 97Jul04 , 97Jul04 Start, stop times (radians): 3.161737, 6.283113 Orbiting body number : -58 Tracking Downlink Position Opening leapsecond kernel /ovlbi/ovlbi/naif/data/leapseconds.ker Opening spk file name /s3/ftp/ovlbi/in/970702-970710-p.bsp Summary of spk file entries for body -58 ------------------------------------------------------------------------------- Segment identifier: VSOP Predicts P97183 Body : -58 Center : 399 Reference : DE-200 SPK Type : 1 From (UTC) : 1997 JUL 01 23:58:57 (Day 182) From (ET) : -7.8926400000000E+07 To (UTC) : 1997 JUL 09 23:58:57 (Day 190) To (ET) : -7.8235200000000E+07 ------------------------------------------------------------------------------- START,STOP = 43200 86398, INT = 5 UT1-UTC= 0.51419285313442 GBES X,Y,Z = 884084.264 4924578.747 3943734.340 m newton: 4.4535892796605D-02 -1.2956969036569D-05 13351.524770719 -3.8844564239200 0. 3 X: 1401.1518901589 -13186.059357135 1558.1481681578 V: 2.9359370260644 3.8966152121734 -2.9497261508861 OPEN OUTPUT FILE : /ovlbi/ovlbi/in/970702-970710-p.orb.h At UTC Hour 12 (LAST= 1.51435, H ANG= 7.11211 hours ) GBES X,Y,Z= 4613.1715125661 1934.4484077190 3944.9561891000 Body RA, DEC = 276.03363114888 6.7039679372756 Deg AZ, EL = 285.76931936142 -8.6706783808058 Deg NUTATE + PRECESSION MATRIX: 0.99999981 0.00056365 0.00024493 -0.00056366 0.99999984 0.00004739 -0.00024490 -0.00004753 0.99999997 At UTC Hour 13 (LAST= 2.51709, H ANG= -7.66327 hours ) GBES X,Y,Z= 3953.0316305344 3065.5887946509 3944.8482413378 Body RA, DEC = 152.70541859916 -37.552637038208 Deg AZ, EL = 110.55658691980 -39.852666202557 Deg NUTATE + PRECESSION MATRIX: 0.99999981 0.00056362 0.00024492 -0.00056364 0.99999984 0.00004739 -0.00024489 -0.00004753 0.99999997 At UTC Hour 14 (LAST= 3.51983, H ANG= -9.16346 hours ) GBES X,Y,Z= 3021.9643809854 3986.6626080058 3944.6639784005 Body RA, DEC = 190.24927318914 -0.58001581503854 Deg AZ, EL = 56.356591657247 -35.686613001236 Deg NUTATE + PRECESSION MATRIX: 0.99999981 0.00056360 0.00024491 -0.00056361 0.99999984 0.00004739 -0.00024488 -0.00004753 0.99999997