converting between EME2000 and true-of-date coordinates - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: HP Software Libraries (/forum-10.html) +--- Forum: HP Prime Software Library (/forum-15.html) +--- Thread: converting between EME2000 and true-of-date coordinates (/thread-19270.html) converting between EME2000 and true-of-date coordinates - cdeaglejr - 12-08-2022 04:34 PM This HP PPL program demonstrates how to convert between true-of-date and eme2000 state vectors and classical orbital elements. The software requires an initial UTC calendar date and time along with position and velocity vectors. The following is an example input to the program that converts an EME2000 state vector (r2000 and v2000) to the corresponding true-of-date state vector. // UTC calendar date (month, day, year) month := 4; day := 6; year := 2004; // UTC time (hours, minutes, seconds) utc_hr := 7; utc_min := 51; utc_sec := 28.386009; // eme2000 x-component of position vector (kilometers) r2000(1) := 5094.5147804; // eme2000 y-component of position vector (kilometers) r2000(2) := 6127.3664612; // eme2000 z-component of position vector (kilometers) r2000(3) := 6380.3445328; // eme2000 x-component of velocity vector (kilometers/second) v2000(1) := -4.746088567; // eme2000 y-component of velocity vector (kilometers/second) v2000(2) := 0.786077222; // eme2000 z-component of velocity vector (kilometers/second) v2000(3) := 5.531931288; The software and documentation for this application can be downloaded from https://www.dropbox.com/s/4ci4tok1ygugdkw/demo_eme_tod.zip?dl=0