The Inclination Window for Low Earth Sun Synchronized Satellite Orbits

Generally, circular orbits of satellites are categorized as Geosynchronous Earth Orbits (GEO), Medium Earth Orbits (MEO) and Low Earth Orbits (LEO). The main difference between them is their attitude above the Earth’s surface (Richharia, 1999; Roddy, 2006; Maral and Bousquet, 2002). The Sun synchronization feature is typical for LEOs. Sun synchronized low Earth orbits have a very wide application in scientific missions based on photo imagery, like weather, Earth observation and space exploration (Oberright, 2004). The specific application of LEO satellites is related to location determination in case of maritime distress. The satellite system is designed to raise distress alert and provide location data to assist in search and rescue operations. A satellite detects and locates distress beacons (406 MHz) activated at a distress location. The system calculats the location of a distress event using Doppler processing techniques (Cakaj et al., 2010). A natural phenomenon like nodal regression effect enables orbital Sun synchronization (Chobotov, 2011). The satellite’s position in space is defined by space orbital parameters, briefly described in the second section. The mathematical background of nodal regression is also provided. Finally, the last section deals with the defined conditions for sun synchronization to be attained at different orbital attitudes. The paper ends with the inclination window determination for sun synchronization of low Earth orbits.