Junghyun Lee Junghyun Lee Additional information is available at the end of the chapter

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.71047

#### **Abstract**

Navigation is the method for determining position, speed, and direction of the object. That is mainly classified into two groups: physical model-based methods (PMMs) and external data-based methods (EDMs). Examples of PMMs are inertial navigation systems (INS) and dead-reckoning navigation. They determine the existing position of an object by measuring various changes in its state, such as velocity and acceleration. Representative EDMs is the global navigation satellite system (GNSS). In the case of spacecraft, auxiliary navigation systems using data compression were proposed. In the case of low earth orbit satellites, the deviations between nominal and real orbit are compressed in the form of Fourier coefficients by using the periodic characteristics of the trajectory. In the event of Deep space explorer, B-spline based orbit compression and transmission was proposed.

DOI: 10.5772/intechopen.71047

**Keywords:** navigation, GNSS, INS, B-spline, data compression
