Aircraft Navigation System

The above system utilizes three types of sensors information:

1. Absolute position data from radio aids, radar checkpoints, and satellites (based on the range or differential range measurements.
2. Dead-reckoning data, obtained from inertial, Doppler, or air-data sensors, as a means of extrapolation present position. A heading reference is required in order to resolve the measured velocities into the computational coordinates.
3. Line-of-sight directions to stars, which measure a combination of position and attitude errors.

The navigation computer combines the sensor information to obtain an estimate of the aircraft's position, velocity and attitude. The best estimate of position is then combined with waypoint information to determine range and bearing to the destination. Bearing Angle is displayed and sent to the autopilot as a steering command. Range to go is the basis of calculations, executed in a navigation or flight-management system, that predict time of arrival at waypoints and that predict fuel consumption. Map displays, read from on-board compact discs(CD-ROM), are driven by calculated position.

Dead-reckoning:- Navigating the aircraft without external navigation/guidance.

Attitude:- Orientation of the aircraft relative to Earth's horizon. / Vertical Navigation to aircraft.

Waypoint:- are the positions and marks in a way.

Bearing Angle:- Its the angle between forward direction of aircraft and a line towards the destination/object in question with respect to north.

Flight Management System:- Its a system which provides workload-reducing automation on flight deck with true multi-sensor navigation capabilities.

Map Displays:- Also known as Moving Map Displays are a type of moving electronic display typically used in GPS navigation devices.

C.E.P:- Circular Error Probable is an indicator to the weapon system which delivers accuracy as factor in determining the probable damage to a target. Its the radius of circle within which half of a missile's projectiles are expected to fall.

Source:- 

• Syed Najeeb Haider Jafri, Assistant Prof. & Deputy Director at PAF-KIET, Pakistan
• Avionics Navigation Systems by Myron Kayton & Walter R.Fried, 2nd Edition