INS-Inertial Navigation System

Inertial Navigation System PPT

1. Inertial Navigation System (INS) BRIGHTLIN ABISHA W DEPARTMENT OF AERONAUTICAL ENGINEERING

2. Introduction High accuracy Self-contained Autonomous – does not depend on other systems Passive – does not radiate Unjammable Does not require reference to the ground or outside world.

3. Introduction The INS can provide: Accurate position in whatever coordinates are required – e.g. latitude/ longitude, etc. Ground speed and track angle. Euler angles: heading, pitch and roll to very high accuracy. Aircraft velocity vector The self-contained characteristics of an inertial navigation system plus the ability to provide a very accurate attitude and heading reference led to the installation of IN systems in long range civil transport aircraft

4. A BASIC INERTIAL NAVIGATION SYSTEM.

5. Introduction The basic principles of any IN system are to derive the components of the aircraft’s acceleration along locally level axes, generally the North and East axes, using an orthogonal set of accelerometers and gyros to measure the aircraft’s motion. Integration with respect to time of these acceleration components then gives the aircraft’s North and East velocity components, knowing the initial conditions. The aircraft’s position in terms of its latitude and longitude coordinates can then be derived

6. Basic Components A stable platform oriented to maintain the accelerometers horizontal to the Earth and to provide azimuth orientation. The accelerometers arranged on the stable platform to supply specific components of acceleration. The integrators to receive the output from the accelerometers and to calculate velocity by integrating acceleration once and integrating again to calculate the distance. A computer to receive the signals from the integrators and to change to distance travelled into latitude and longitude.

7. INS Sensor

8. Inertial Sensors Inertial sensors are associated with the detection of motion in a universal (non-Earth) referenced set. Inertial sensors comprise: position gyroscopes; rate gyroscopes; accelerometers.

9. Accelerometer The basic principles upon which the accelerometers operate are related to Newton's laws regarding motion. Linear accelerometers measure object’s linear acceleration and therefore detect direction of object’s movement. Most accelerometers are able to measure acceleration along one axis. In an inertial navigation system, two or three accelerometers are used. One will measure the aircraft’s accelerations in the North-South directions. Second one will measure the aircraft’s accelerations in the East-West directions. The third accelerometer, if fitted, will measure vertical displacement.

10. Accelerometer

11. Gyroscope Gyroscopes are rotational sensors that measure the angular velocity or orientation of a device. Gyros can be used as rate gyros or integrating gyros. There are different types of gyroscopes such as :Mechanical, Optical and MEMS gyroscopes.

12. Position Gyroscope

13. Rate Gyroscope