Airport Engineering Planning, Design, and Development of 21st ...

Technology Background
6.1 Evolution of the System 181
As stated earlier, the technological development for airport CNS has gone through three
major development phases of navigation from inception, as discussed below.
Visual Navigation. Airport navigation started with an entirely visual system whereby
the pilot was the sole member in the system working under the concept of “see and be
seen” with other pilots. This was later translated into visual flight rules (VFRs), and
this is still recognized today. Later, an airport controller on the ground or in an elevated
platform (tower) conveyed to the pilot basic control instructions visually, first through
colored flags, then using colored “light guns” to instruct the pilot of certain actions
to take at certain gun colors emitted—steady green for cleared for takeoff ; flashing
green for cleared to taxi; steadyredforstop; and alternating red and green for exercise
extreme caution. With the advent of radio communication, the ground controller at the
airport tower would relay information and instruction to the pilot through the radio.
Airport radio navigation was born in the 1930s in Cleveland, Ohio, with a 15-W
transmitter–receiver radio with a 15-mile range.
Today, airport visual navigational aids include all airfield signs and markings,
runway and taxiway centerline and edge lighting, runway light landing aids, and aircraft
gate docking systems. These will be described individually later.
Radio Navigation and Communication and Radar Surveillance. Radio was first
used in the early days of aviation for airport navigation strictly through communicating
between ground controllers and pilots to provide direction for them to navigate their
approach and landing. In the era between the two great wars, extensive research was
conducted on using radio waves to detect objects, which culminated in the discovery of
the RAdio Detection And Ranging technology, or radar. Radar and other radio-based
navigation technologies were developed, perfected, and used during the war effort. By
the end of World War II, air navigation and surveillance technologies were mature and
were immediately utilized for civilian commercial use in airways and airports in the
United States and around the world.
Radio-based navigation includes such technologies as marker and nondirectional
beacons, VOR, DME, TACAN, VORTAC, LORAN, instrument runway approach and
landing systems (ILSs), and microwave landing systems (MLSs).
Radio communication is still the backbone of the communication system between
pilots, controllers on the ground, and an array of radio-based ground navigation equipment.
To avoid interference between all radio frequencies, duplex communication was
adopted that isolates voice communication from navigation-based transmitter–receiver
frequencies. Today, modern cockpit communication relies on the simplex transmission
principles with elaborate frequency assignment of blocks of VHF bands for various uses.
In terms of surveillance, an array of radar types and technologies are in use today,
ranging from primary and secondary radars that include ASR, ARSR, and PAR; automated
ARTS series radars; and airport surface detection equipment (ASDE) radars.
These technologies and equipment are also described.
Satellite-Based Navigation, Communication, and Surveillance. As air traffic
continued to grow, system inefficiencies and associated costs were compounded by
constraints on the air traffic control (ATC) system. Technologies implemented in the