Apparent Magnitude Measurement of Geosynchronous Orbit Space Object Based on Phong Model

Abstract

There are a lot of spatial objects running along the geosynchronous orbit (GEO). Estimation of the shape and attitude of space objects by using light curves provides a method for object tracking, identification and surveillance. The temporal and spatial relationship among the sun, satellite and observation station under different orbit parameters is obtained via coordinate transformation by using the STK software. According to the definition of apparent magnitude, the calculation model suitable for cube, prism and cylinder objects is derived with the facet method based on the Phong model. Through comparison with the measured data, it is demonstrated that the simulation error of the model is about 3%, the simulation result is far better than the result obtained by the apparent magnitude model only characterized by the diffuse reflectance. Based on the Matlab software, the light curves of satellites with different segments, shapes and sizes are simulated. The study shows that the nonlinear filtering technique is adopted for inversion if obtained light curves have better quality, otherwise the two-facet analytical model is used. The research offers a reference for the inversion based on light curves.