TABLE OF CONTENTS As described in Chapter 1, inertial navigation relies upon the measurement of acceleration which can be integrated successively to provide estimates of changes in velocity and position. Measurements of acceleration are used in preference to direct measurements of velocity or position because velocity and position measurements require an external reference whilst acceleration can be measured internally.
The form of construction of devices which may be used to sense acceleration may be classified as either mechanical or 'solid-state'. The technology of mechanical sensors is well established [1, 2] and devices capable of sensing acceleration over a wide accuracy range, from 50 milli- g down to a few micro- gs and to a similar level of resolution, are currently available. There have been significant advances in the development of solid-state sensors in recent years, particularly with silicon technology.
The concept of using a single instrument to measure acceleration and angular motion has been the subject of research for a number of decades and during the 1980s was developed by a number of institutions and companies. This device has become known as the multi-sensor and has tended to be based on either vibratory technology or gyroscopic mass unbalance technology. Evaluation of this technology has generally shown it to be capable of providing estimates of linear acceleration and angular motion compatible with sub-inertial [1] navigation applications.
[1]The term sub-inertial is sometimes used when describing system performance for short duration navigation systems. Typically, sub-inertial systems use gyroscopes and accelerometers...
