Orbit Determination

Abstract

Determining orbits from measurements has been done for hundreds of years. The general approach is to take a series of measurements of the object from the ground at different times. Possible measurements are range and range rate from the observation point or angles of the object from the measurement point. Given the location from where the measurements are taken on the Earth and this set of data, one can reconstruct the orbit. Ideal orbits, which assume that the Earth’s gravity is represented by a point mass at the center of the Earth, are conic sections. Those that stay near the Earth are ellipses. These can be defined as a set of orbital elements. In this chapter, we will design a neural network to find the values for two of the elements. Our model will be simpler than that which astronomers must use. We will assume that all of our orbits are in the Earth’s equatorial plane and that the observer is at the center of the Earth.