Speaker
Description
While VSOP87 is a historically significant analytical model, precise numerical models from JPL, such as DE440, are the current standard. This project investigates the extent to which classic French trigonometric tables can produce results comparable to modern NASA navigation algorithms, provided that appropriate corrections are applied.
Using Python, we developed a computational model to calculate the distance between a topocentric point on Earth and a specific location on Mars over a given time span. Our algorithm systematically applies successive layers of corrections to baseline models (Keplerian orbits, VSOP87, and DE440). First, it converts time scales (UTC to TDB) and translates the Earth-Moon barycentric state vector to the Earth’s center of mass. Next, it applies geodetic and topocentric adjustments, including conversion to 3D Cartesian coordinates, Earth's polar motion, calculation of Greenwich Mean Sidereal Time (GMST), and rotation matrices for Earth’s precession, nutation, and the Mars rotation angle. Finally, the model calculates signal propagation delays by computing two-way light time and the relativistic Shapiro delay.
The poster will present an analysis of the differences between these models and evaluate the contribution of individual corrections to the final accuracy of the calculated distance. The results will help assess the applicability of analytical solutions in modern planetary geodesy.