Publication: Magyar Közlöny
Issue: MK-2007-70 (Year: 2007, Number: 70)
Era: 2004-2010
Section: Melléklet a 2007. évi XLVI. törvényhez
Paragraph Index: 3853

b) the degree of randomness in the dynamic side lobes. Note.— The dynamic side lobes are of least concern, if the measured dynamic side-lobe levels are less than the specified effective side-lobe levels. 3.2.3 Lateral multipath reflections from the azimuth antenna side lobes and ground multipath reflections from elevation antenna side lobes can perturb the main beam and induce angular errors. To ensure that the error dv generated by the antenna side lobes is within the propagation error budgets, the required effective side-lobe level ESL can be estimated using: BW R MA d ESL P P P T T where PR is the multipath obstacle reflection coefficient, șBW is the ground antenna beamwidth and PMA is the motion averaging factor. 3.2.4 The motion averaging factor depends on the specific multipath geometry, the aircraft velocity, the function data rate and the output filter bandwidth. For combinations of multipath geometry and aircraft velocity such that the multipath scalloping frequency is greater than 1.6 Hz, the motion factor is: MA 2 (output filter noise bandwidth) Function data rate P 3.2.5 This factor can be further reduced at higher multipath scalloping frequencies where the multipath-induced beam distortions are uncorrelated within the time interval between the TO and FRO scans. 3.3 Approach elevation antenna pattern 3.3.1 If required to limit multipath effects, the horizontal radiation pattern of the approach elevation antenna gradually de-emphasizes the signal away from the antenna boresight. Typically the horizontal pattern of the approach elevation antenna is to be reduced by 3 dB at 20 degrees off the boresight and by 6 dB at 40 degrees. Depending on the actual multipath conditions, the horizontal radiation pattern may require more or less de-emphasis. 23/11/06 ATT G-12 2007/70/II. szám Attac ment G Annex 10 — Aeronautical Communications 3.4 Approach/back azimuth channels 3.4.1 When a runway has MLS installed for both approach directions, the equipment not in use for the approach may be operated as a back azimuth. If it is desired to assign different channels to each runway direction, necessarily the azimuth units will be operated on different frequencies depending on the mode of operation — approach or back azimuth. Care must be taken in the channel assignments so that the two frequencies are close enough to avoid any mechanical adjustment of the azimuth antenna vertical pattern when the approach direction is reversed. 3.4.2 The frequency separation should be limited such that the loss in pattern gain for back azimuth (from the optimum approach value) can be accommodated by the transmitter power margins shown in Table G-1 for the back azimuth function. 4. Siting considerations 4.1 MLS/ILS collocation 4.1.1 MLS elevation antenna 4.1.1.1 Introduction 4.1.1.1.1 When collocating an MLS elevation antenna with an ILS glide path, a series of decisions will have to be made to determine an elevation antenna location. Siting criteria have been developed based on minimizing the effects of MLS elevation equipment on the ILS glide path signal. This criteria along with signal-in-space, operational, critical areas, and obstacle clearance considerations will influence the final location of the elevation antenna. 4.1.1.1.2 The purpose is to start with a general region for siting the elevation antenna and then to reduce this region to an optimum location for a particular facility. This goal is achieved by stepping through a series of factors and considerations. This decision-making process is shown as a logic flow diagram in Figure G-17. These guidelines are not intended to be an all-inclusive MLS siting manual, but only to provide additional guidance when MLS collocation with ILS is required. 4.1.1.1.3 Referring to Figure G-17, the section number corresponds to one of the three siting geometries, that is 4.1.1.2 for “siting the elevation antenna between the glide path and runway”, etc. The numbers in each block reference the specific paragraph in the supporting text for Figure G-17. This paragraph provides a more detailed description of the factor(s) to be considered for that step. 4.1.1.1.4 The two general regions for siting the elevation antenna are shown in Figure G-18. Depending on the location of the glide path, either one region or the other may not exist. In addition, these regions must already satisfy signal-in-space criteria prior to their consideration. 4.1.1.2 Siting the elevation antenna between the glide path and the runway 4.1.1.2.1 The setback for the elevation antenna is dependent upon the MLS approach reference datum (ARD) height. The MLS ARD must satisfy the criteria stated in Chapter 3, 3.11.4.9.1. The elevation antenna setback can be determined by the equation (see Figure G-19): tan tan AR RPC RPC SB   t T T ATT G-13 23/11/06 2007/70/II. szám Annex 10 — Aeronautical Communications Volume I Where: all distances are in metres; SB is the setback distance of the elevation antenna phase centre from the runway threshold, parallel to the runway centre line; RPCH is the relative phase centre height of the elevation antenna compared to the runway surface at threshold. (This includes the elevation antenna phase centre height and the difference in terrain elevation between the threshold and the elevation antenna site.); ARDH is the desired MLS approach reference datum height; and ș is the minimum glide path. 4.1.1.2.2 The conical coordinate system of the elevation antenna and its offset from centre line will cause the minimum glide path elevation guidance to be above the approach reference datum. Considering the recommendation of Chapter 3, 3.11.5.3.5.2.2 this offset should be limited by the following equation: tan RPC OS SB  ª º  d « » T ¬ ¼ Where: all distances are in metres; and OS is the offset distance between the elevation antenna phase centre and the vertical plane containing the runway centre line (see Figure G-19). 4.1.1.2.3 Furthermore, the MLS ARD should be coincident with the ILS reference datum within one metre as stated in Chapter 3, 3.11.5.3.5.3. This is given in the following equation: tan tan R RPC R RPC SB     d d T T Where: all distances are in metres; and RDH is the height of the ILS reference datum. 4.1.1.2.4 To determine the diagonal boundary for Region 1 of Figure G-18 two factors need to be considered. The first factor is that the elevation antenna must not penetrate the region through which the Fresnel zone for the ILS glide path migrates during an approach. In general, this requirement can be achieved by siting the elevation antenna to the runway side of the diagonal line between the glide path antenna mast and the runway centre line at threshold. The value for ĳ in Figure G-18 is dependent on the location of the glide path antenna mast relative to centre line at threshold. The second factor is to minimize lateral penetration of the glide path antenna pattern (see 4.1.1.3.2). However, for this elevation antenna region satisfying the second factor is preferable but not essential. 4.1.1.2.5 After determining the acceptable range of elevation antenna locations based on the above criteria, the minimum elevation antenna offset is determined by the obstacle limitation requirements in Annex 14, Chapter 4. 4.1.1.2.6 When possible the elevation antenna location is to be adjusted to minimize the effects of the elevation antenna critical area on flight operations. Furthermore, it may be desirable to choose the elevation antenna location in a way 23/11/06 ATT G-14 2007/70/II. szám Attac ment G Annex 10 — Aeronautical Communications which maximizes the union of the MLS elevation critical area and the ILS glide path critical area. This union will minimize any enlargement of the combined critical areas. Due to the necessity to site the elevation antenna in front of the glide path, the elevation antenna will normally have to be sited in the glide path critical area. For elevation antenna critical areas see Section 4.3. For a description of the glide path critical area see Attachment C, Section 2.1.10. 4.1.1.2.7 Once the site for the elevation antenna has been identified, a location for the elevation antenna monitor must be found. The elevation signal is to be monitored as stated in 2.4.3. The height of the elevation field monitor is dependent on the use of integral monitoring of the minimum glide path and obstacle clearance criteria. The following considerations may be helpful in determining a monitor location:

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