Glidepath Antenna Design

The GP antenna comprises a lattice mast with three dipole antenna arrays A1, A2 and A3. The mast using the dimensions (W x D) 450 x 650 [mm] is rectangular and may be mounted by way of stirr ups.The mast is divided in sections of 3.50 m in length each, and can be adapted to satisfy nearby specifications.Each mast section comprises 4 bars connected collectively via struts and butt straps by indicates of rivets and screws. It's produced of aluminium ALMgSi, the metal parts are galvanized and all screw connections are created of metal V2A. The base frame is made of welded metal profiles. It consists of forked bolts which allow the mast to become tilted. The erected mast is fixed with supports. The mast suggestion is made of welded U-profiles. It includes two deflection rollers produced of polyamide for an auxiliary guy wire when installing the antenna dipoles, and 2 obstacle lights. The antenna mounting for the dipole array is really a buckled C-profile which permits a horizontal adjustment of the dipole array by about ±350 mm. The C-profile is mounted at a vertical tube 1 m long that is fixed to the mast by cross-strucks. With the vertical tube a fine vertical adjustment of the antenna array is possible. In addition the height of the complete body can be adjusted in actions of 500 mm. The mast is painted in red and white for 1.75 m alternately.The 3 dipole antenna arrays A1, A2 and A3 have a horizontal polarization and an identical design using the dimensions (H x W x D) 500 x 2000 x 250 [mm]; they're mounted over 1 an additional and somewhat offset. The antennas are protected against weathering exposure with a polyester glass fibre cover. They remain operational, even in case of substantial formation of ice. Atmospheric discharges are eradicated reliably, since all metal parts of the antenna are linked to floor.The reflector surface area in front of the GP antenna consists of a welded construction-steel internet which is embedded in gravel and which should be grounded. If preferred, the construction-steel web can also be embedded in asphalt, concrete or similar. The use of structural metal mesh isn't mandatory. Depending on the local conditons it may be established during website survey, if it is suggested or necessary.

LORAN-C

LORAN(Long Range Navigation) is a terrestrial radio navigation system using low frequency radio transmitters in numerous deployment to determine the location and pace of the receiver.The most recent version of LORAN in use is LORAN-C, which operates in the reduced frequency portion of the electromagnetic spectrum from 90 to 110 Kilohertz. Numerous nations have utilized the program, such as the us, Japan, and a number of European nations. Russia uses a nearly identical system within the same frequency range, called CHAYKA.
 

LORAN use continues to be in steep decline, using the satellite primarily based Global Positioning Program (GPS) being the primary substitute. However, there have been attempts to enhance and re-popularize LORAN, primarily to serve as being a backup and land-based alternative to GPS along with other International navigation satellite system (GNSS) techniques.The present LORAN program has been phased out in the Usa and Canada. The united states Coast Guard (USCG) and Canadian Coast Guard (CCG) ceased transmitting LORAN-C (and joint CHAYKA) indicators in 2010.

The navigational technique offered by LORAN is dependant on the key with the time distinction in between the receipt of indications from the set of radio transmitters.[6] A offered continuous time distinction in between the indications in the two stations might be symbolized with a hyperbolic type of place (LOP).When the positions with the two synchronized stations are recognized, then your place with the receiver might be established as becoming somewhere on the specific hyperbolic curve exactly where time distinction in between the acquired indications is continuous. In perfect conditions, this really is proportionally equal towards the distinction with the distances in the receiver to every with the two stations.

A LORAN network with only two stations can't offer significantsignificant navigation info because the 2-dimensional place with the receiver can't be fixed due to towards the stage ambiguities within the program and absence of the outdoorsoutdoors stage reference.A second software with the identical principle should be utilized, according to time distinction of the various set of stations. In apply, 1 with the stations within the second pair also might be-and frequently is-in the very first pair. In easy phrases, this suggests indications should be acquired from a minimum of 3 transmitters to target the receiver's place. By identifyingdetermining the intersection with the two hyperbolic curves recognizedrecognized with this technique, a geographic repair might be established.

Tactical Air Navigation (TACAN)

A tactical air navigation technique, generally referred to through the acronym TACAN, is actually a navigation method used by military aircraft. It provides the person with bearing and distance (slant-range) into a ground or ship-borne station. It is just a much more precise model with the VOR/DME technique that gives bearing and variety data for civil aviation. The DME portion from the TACAN method is available for civil use; at VORTAC amenities wherever a VOR is combined with a TACAN, civil plane can receive VOR/DME readings. Aircraft equipped with TACAN avionics can use this system for enroute navigation too as non-precision approaches to landing fields. The room shuttle is one such automobile which was built to use TACAN navigation[citation needed despite the fact that it has since been upgraded with GPS like a substitute. The common TACAN onboard consumer panel has handle switches for setting the channel, the operation mode for both Transmit/Receive (T/R, to have both bearing and array) or Receive Only (REC, to acquire bearing although not assortment). Capability was later upgraded to incorporate an Air-to-Air mode (A/A) where two airborne customers can get relative slant-range information. Based on the installation, Air-to-Air mode could supply assortment, closure (relative velocity with the other unit), and bearing,  however an air-to-air bearing is noticeably less precise than a ground-to-air bearing.TACAN on the whole might be described as the army edition from the VOR/DME method. It operates from the frequency band 960-1215 MHz. The bearing unit of TACAN is much more correct than a standard VOR since it makes usage of a two frequency principle, with 15 Hz and 135 Hz parts.The gap measurement part of TACAN operates with all the identical specifications as civil DMEs. Therefore to cut back the quantity of necessary stations, TACAN stations are often co-located with VOR services. These co-located stations are known as VORTACs. This is a station composed of a VOR for civil bearing information along with a TACAN for army bearing information and military/civil length measuring information. The TACAN transponder performs the operate of the DME with no the require to get a separate, co-located DME. As the rotation of the antenna produces a big portion in the azimuth signal, should the antenna fails, the azimuth component is no longer obtainable as well as the TACAN downgrades to a DME only mode.

Distance Measuring Equipment DME

DME

DME (Distance Measuring Equipment) is a radio aid for short and medium distance navigation. It can allows 100 aircrafts simultaneously to measure their distance from a ground reference (DME transponder). The distance is determined by measuring the propagation delay of a gaussian pulse, which is emitted by the aircraft transmitter and returned by the ground station after reception.DME operates in the frequency range of(960 to 1215 MHz).

Aircraft's airborne interrogator transmit encoded interrogating  pulse pairs on the ground station. The DME station in turn, transmits encoded reply pulse pairs on the air-borne equipment, The real distance information is the time interval between interrogation emission and reply reception. Aircraft's equipped with DME transmit encoded interrogating RF pulse pairs about the beacon's obtaining channel. The beacon, consequently, emits encoded reply pulse pairs about the receiving channel with the air-borne tools, that is 63 MHz apart from the transmitter frequency former.

Time interval among interrogation emission and reply reception provides the aircraft with all the real
distance data through the ground station; this info could be go through from the pilot or even the navigator straight around the airborne indicator. The ground transponder is capable to reply approximately about 200 interrogators at a time (i.e. 4800 pulse pairs/s). Generates random pulse pairs ("squitter") to take care of a minimum PRF of 800 to 2700 pulse pairs per
2nd (programmable) whenever the amount of decoded interrogations is decrease than that.
This reply is obtained and decoded by the airborne receiver, where unique timing circuits automatically measure the lapse between interrogation and reply and convert this measurement into electrical output indicators. The beacon introduces a fixed delay, known as reply delay, among the reception of each encoded interrogating pulse pair and also the transmission of the corresponding reply.

INSTRUMENT LANDING SYSTEM (ILS)

An  (ILS)  Instrument Landing System is a ground-based equipment that radiates guidance information to be received by an aircraft during final approach for correct and safe landing. It is composed of ground based equipments such as transmitter, combining/dividing network, antenna and monitors systems.

ILS have three subsytem: Localizer, Glidepath/Glideslope and Marker Beacons.

 

A.The vertical plane containing the runway centerline is defined by VHF transmitter called Localizer.

B.The horizontal plane of 2 to 4º of vertical angle above the horizontal plane is defined by a UHF transmitter called the Glide slope.

C.Distance information installed on a fixed distance reference points are provided by markers.

MARKER BEACONS

Beacons are AM transmitters operating at 75 MHz located at specific points along the landing path used to designate distance away from the threshold.

Operating  Radio Frequency

  75 MHz  ± 0.01%

Modulating Frequency

  Inner  Marker (when installed) : 3000Hz

  Middle Marker: 1300 Hz

  Outer Marker: 400 Hz

Coverage

  Inner Marker (when installed) 150 m ± 50 m

  Middle Marker : 300 m ± 100 m

  Outer Marker : 600 m ± 200 m

Identification Signal

  Inner Marker (when installed): 6 dots per second continuously

  Middle Marker: Series of dots and dashes

  a. dashes keyed at a rate of 2 dashes/sec

  b. dots keyed at a rate of 6 dots/sec

  Outer Marker: 2 dashes/sec continuously

Monitoring

  Automatic Monitoring System that transmit a warning signals to  a control point    during

  a.  Failure of modulation or keying

  b. Reduction of Power output to less than 50%