LORAN (Long Range Navigation) The latest system known as LORAN-C .This system will be discontinued due to cost not effective. The US will continue to operate the LORAN-C system beyond the previously planned December 31, 2000. The termination date is continuing to evaluate the long term need for continuation of the system. User will be given reasonable notice so that they will have the opportunity to transfer to alternative navigation aids. At this time we will talking about this system a little because they might keep this system as a back up system.

OPERATION LORAN is a net work of land based radio transmitters and was developed to provide an accurate system for long range navigation. LORAN Stations Operations are organized into sub-groups of four to six stations called " CHAIN ".One station in the Chain is designated the " MASTER " and others are called " SECONDARY " or " SLAVE " Stations.


The theory is to calculate the time between reception of the signals from the MASTER and SLAVE stations, which are emitted at different frequencies , at low or very low bands 90kHz - 110 kHz. in pulse group and has power of 400 - 1600 kilowatts. The master station emits its own signal first, when that signals reach the slave station , it emits its own signal after a predetermined delay. When the master station's signal reaches the aircraft , its Navigation system counts the time until the slave station's signal arrives. Your position is found as the intersection of the line of two LORAN stations.

LORAN UNIT

SIGNAL PROCESSOR

NAVIGATION COMPUTER

CONTROL and DISPLAY
     Signal Processor receives the signals and measures the difference between the time of arrival of each secondary station pulsegroup and the master station pulse group. The time difference is depend on the location of the receiver on the aircraft in relation to the three or more transmitters.Each time difference value is measured to a precision of about 0.1 microseconds.
     Navigation Computer converts time difference values to location corresponding latitude and longitude.
     Control and Display


     The functions of the LORAN UNIT is:

Preset Position in Latitude-Longitude and/or relative to a destination, waypoint or check point.

Bearing and distance to your destination

Ground speed and estimated time enroute.

Course Deviation Indicator.

Storage in memory of airports.add-on programable and updatable database.

Continuous computation of bearing and distances to the nearest airports. computation of wind direction and velocity.

Add-on such as fuel flow analyzers to estimate fuel need to reach destination.etc.