-
enroute tasks (overflying aircraft,
far approach segment; almost 360° coverage in azimuth and up to high
elevation angles)
-
terminal task (final approach and intercept
segment; relatively sectorial coverage determined by the runway extention
volumes). It is anticipated that this control zone is at least within the
socalled course sector of ILS (± 10° LOC)
-
final landing phase as part of the terminal
task down to a certain height of the aircraft (e.g point B middle marker
or earlier. Dependant on the position of the radar the angular coverage
range can be relatively large.
Fig. 2 shows the general layout for
the Brussels international airport Zaventem. This airport has 3 fully operable
runways in a parallel and a V-orientation. The four radar locations are
marked on this figure. In addition the course sectors (± 10°)
are marked by dashed lines for each of the 6 principal landing course sectors
related to the ILS. Finally, one particular new planned terminal ("terminal
A") is clearly depicted also. The potentially dangerous azimuthal section
as well as approximately the coverage sectors for the PSR/MSSR-radars are
identified. Fig. 3 shows a tridimensional model of a part of the Brussels
airport around the new terminal A. It can be seen that this building is
illuminated by the radars and by the ILS from all around and with very
different signal characteristics.
In total, the airport radar problem
is highly tridimensional. The coverage is tridimensional, the relative
locations of the radar systems (xR,yR,zR)
are tridimensional and the buildings/objects (hangars, terminals, tower
etc.) are highly tridimensional also. The surface and wall materials present
a further parameter.
The frequency and polarisation characteristics
of the airport radars are relatively wide, see the following Table 1. The
navaids systems on an airport are added also in this table.
It is very important in the context
of the multipath analysis that the modern primary and secondary radar differ
in frequency by a factor of 2.7 and in case by the polarisation characteristics
also. The weather radar as well as the wind profiler radar are in the terminologie
of the context a "primary radar" also.
| Radarsystem |
Systemparameter |
Coverage |
Frequency
/MHz |
Polarisation |
| primary
ASR/PSR |
reflected
signal; A ; 2D (r, (J),j) |
terminal
j=360°, in case selected priority az-angle ranges
en-route 360°; limited elevation
resolution |
L-band
|
linear, circular |
|
S-band,2700 |
| secondary
SSR, MSSR |
transponder
resp.; (r,,j), (data, height of aircraft) |
360°
no (or limited) elevation resolution |
L-band, 1030 |
linear |
| Airport ground-radar
ASDE |
reflected
signal
A; 2D (r,,j), |
airport area |
X-band, Ku |
linear |
| weather |
A,F,
Doppler-F; 3D (r, J,j) |
-2°,
+92° |
S/C-band |
linear |
|
|
|
|
|
| ILS |
DDM,SDM |
±
35°, ± 8° |
VHF 0.110,
UHF 0.330 |
linear horizontal |
| MLS |
J,j, (r) |
±
40°, 1°-15° |
C-band, 5060 |
linear vertikal |
| VOR/DVOR |
j, m |
360°,
40° |
VHF 0.110 |
linear horizontal |
| DME |
d |
360°,
40° |
962 – 1213 |
linear vertikal |
| TACAN |
d, j, m |
360°,
0° ...40° |
962 – 1213 |
linear vertikal |
| GPS |
x,y,z,t |
360°,
0° ... 90° |
1227, 1575 |
circular |
|
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