THE HISTORY OF AN AIRCRAFT DME

The History of an Aircraft DME

The History of an Aircraft DME

History of Distance Measuring Equipment

Distance measuring equipment (DME) is the technology-based navigation radio transponder that measures distance by time propagation delay of VHF or UHF signals (Mike, 2008). It was developed in Australia, which was invented by George Edward "Taffy" Bowen while working as chief of Division of Radio physics of Commonwealth Scientific and Industrial Research Organization (CSIRO). Another version of system engineering was implemented by Amalgamated Wireless Australasia Limited in 1950 operating in 200 MHz band VHF. Australian national version was submitted by Federal Department of Civil Aviation as DME (D) (DME or home), and later adopted by ICAO international and DME (I). (Justin, 2009)

DME is similar to secondary radar, but in reverse. System was the post-war development of IFF (identification friend or foe) systems of Second World War. For compatibility, DME is functionally identical to distance measurement component of TACAN (Mike, 2008). It is used by many riders for their comfort during flight is airborne equipment and ground usually co-located. DME provides distance (and in some systems, ground speed) indicative of ground floor. DME (P) DME accuracy is used in conjunction with MLS. (Justin, 2009)

DME as Future Technology

It is a Future Technology because it operates in UHF frequency band, however, their frequency can be "paired" with VOR or ILS or localizer (LOC) frequencies. Receiving equipment in most aircraft provides automatic DME selection through the VOR / LLS coupled receptor. Selecting appropriate VOR or ILS frequency automatically adjusts DME. (Mike, 2008)

It can also receive information from the TACAN station by regulating "couple" of frequency. This VHF frequency found in navigation data box for installation of land listed in table of IFR en route. It operates in ultrahigh frequency (UHF), so it is limited to transmission line of sight. With proper height, pilot can receive DME signals en route to the distance of more than 200 NM, with an error of ± 0.25 nautical miles (NM) or 1.25% of distance, whichever is greater. DME approach is combined with an ILS or LOC has the nominal range of about 40 NM. (Michael, 2008)

Transceiver that sends interrogation signal to ground station contains an internal team to measure length of time that elapses until answer. Antenna used for transmission and reception, is the very small "shark fin" usually mounted on bottom of aircraft. DME controls incorporating modern digital readouts of frequency, DME and information from ground. (Mike, 2008)

Distance Measuring Equipment in Today's World

Most DME radio shows this data on face of radio. Distance to station is the great inclination, expressed in nautical miles. For example, if an aircraft went straight through DME station at 6100 feet AGL, distance indicator would read the mile. DME receiver can express ground in knots. This value is correct only if aircraft is flying directly to or from station, because DME action on ground compared to time lapse between the series of pulses. Information regarding soil allows pilot to make accurate estimates of ...