Global Positioning Systems, Inertial Navigation, and Integration, Second Edition

9

INERTIAL NAVIGATION SYSTEMS

A descriptive overview of the fundamental concepts of inertial navigation is presented in Chapter 2. The focus here is on the necessary details for INS implementation and GNSS/INS integration.

We begin with an overview of some of the technologies used for INS, and how these devices and systems are modeled mathematically. Next, we cover the mathematical modeling necessary for system implementation. Finally, we will delve into mathematical models characterizing how INS errors propagate over time. These last models will be essential for GNSS/INS integration.

9.1 INERTIAL SENSOR TECHNOLOGIES

A sampling of inertial sensor technologies used in inertial navigation is presented in Table 9.1. There are many more, but these will serve to illustrate the great diversity of technologies applied to inertial navigation. How these devices function will be explained briefly. A more thorough treatment of inertial sensor designs is given in [190].

The histories by Draper [47], Mackenzie [129], Mueller [144], and Wrigley [215] contain much more information on the history of inertial systems and sensor technologies and the individuals involved. See also Refs. 8, 63, 110, 168 and the cited references below for more historical and technical details.

9.1.1 Early Gyroscopes

9.1.1.1 Momentum Wheel Gyroscopes (MWGs) The earth itself is a giant momentum wheel gyroscope, the spin axis of which remains pointing at the pole star Polaris. The toy top is essentially a MWG that is ...