Modern Threats to Precision Approach and Landing - The A380 and Windgenerators and their Adequate Numerical Analysis
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Paper ISPA2004 (Intern. Symposium on Precision Approach and Landing), Munich 10/2004
Modern Threats to Precision Approach and Landing - The A380 and
Windgenerators and their Adequate Numerical Analysis
Gerhard Greving
NAVCOM Consult
Ziegelstr. 43
D-71672 Marbach/Germany
navcom.consult@t-online.de
http://www.navcom.de
these objects by the systems themselves.
ABSTRACT These objects can be terminals, hangars,
Classical and modern navigation, landing large buildings, windgenerators and power
and radar systems rely on the radio trans- lines as well as the aircraft itself.
mission and reception. Relevant objects in A reliable prediction of the potential “threat”,
the radiation field can harm the intended i.e. the unacceptable effects on the systems
characteristics of these systems. Modern in question is required in advance before the
state-of-the-art simulation can predict in an objects are built or before the objects appear.
increasing number of complicated cases the This task can be solved today by system
electrical performance in the presence of simulations using state of the art numerical
these objects. Countermeasures can be de- methods. Quite a number of publications
signed from this knowledge. have been released by the author in the past
This paper deals with the "threat" (potentially /2-12/ on the subject of numerical system
un-acceptable distortions) on these systems simulations. This paper highlights two types
by the forthcoming new large aircraft A380 of objects somewhat more fully, namely the
and by the windgenerators which are con- A380 and the windgenerators (Fig. 2). This
structed in an increasing number sometimes paper is not intended to present rules and
close to the systems. The mathematical and definitions for dimensions of safeguarding
numerical analyses are outlined and some areas or safety distances.
results are presented. It is in particular em-
phasized to apply three-dimensional and
sophisticated state-of-the-art methods which MODELING AND SYSTEM SIMULATION
are adapted to the three-dimensional char- The modeling and simulation process (Fig. 3
acteristics of the objects in contrast to inade- and 4) must accomplish the following basic
quately simple methods. tasks
3D-modeling examples for the A380 and · Sufficiently realistic modeling of the object
windgenerators and some principle results having in mind that the subsequent
are presented. simulation is treating the model and not
the reality. The form, the shape and the
materials of the object as well as the ex-
INTRODUCTION citing field above ground have to be
Almost all classic and modern navigation modeled sufficiently. The basic way of
landing and radar systems rely on radio modeling depends also on the numerical
transmission and reception. In a clean en- method used in the next steps.
vironment these systems may work pretty · Detailed modeling of the system in ques-
well, but the real life is different. More and tion which is generating the undistorted
more complex distortion and interference signal.
problems for navaids, landing and radar · Simulations of the reflection and scatter-
systems are encountered today (Fig. 1). ing process by the application of ade-
These so-called “problems” are caused by quately state-of-the-art numerical me-
major objects around and in the vicinity of thods. The most accurate method should
these systems, creating additional reflections be generally used; approximations may
and scattering signals (“multipath signals”) be used only if the results are sufficiently
by the principally unavoidable illumination of accurate.
1/12Paper ISPA2004 (Intern. Symposium on Precision Approach and Landing), Munich 10/2004
· Evaluation of the decisive system pa- certain cases cross checks can be made for
rameter which the aircraft uses for navi- approval by comparing the results of the
gation or landing. preferred approximative IPO-method (im-
The two objects of this paper (Fig. 2; A380, proved physical optics) with the results from
windgenerator) are highly three-dimensional the rigorous MoM- or ML-FMM-methods
and therefore a two-dimensional approach (method of moments, multi-level fast mul-
and model is neither sufficient nor "state-of- tipole method). The latter family cannot be
the-art". It is obvious that a three-dimen- applied efficiently for large aircraft and
sional approach is not only necessary to windgenerators due to the "exploding" stor-
apply, but also requires a lot more modeling age requirements and/or the excessive com-
and computation work. No trade-off is ac- puter time for systematic simulations.
ceptable between the accuracy and the effort Moreover, the ML-FMM has the general
to be invested due to the safety issue in- problem of a questionable convergence of
volved. A simple 2D-treatment which re- the iterative solution of the integral equation.
duces a 3D-A380-aircraft to one rectangular Cases have been experienced where the
plate in the most extreme simplification, or defined convergence criterion, e.g. 10-3, has
several composed rectangular flat plates, not been achieved after 500 iterations for an
can be up to many orders of magnitude aircraft.
faster, but can also yield wrong and unpre- The GTD/UTD method is not the preferred
dictable results /12/. Such kind of simple numerical method for the discussed applica-
approaches cannot be cured by "some tions and three-dimensional curved objects
measurements" at a few points under some due to the general caustic problem and the
conditions. generally unavoidable discontinuities of the
The simulation of the system must take into solution, which results in problematic discon-
account all relevant details which affects the tinuities in the DDM-results for ILS.
so-called "system-parameter" of that particu-
lar system, i.e. the DDM (Difference of Depth For both cases (A380, windgenerator) the
of Modulation) for the ILS (Instrument Land- structure is subdivided into a large number of
ing System) or the "bearing error" for the metallic triangles (Fig. 7 and 10) where the
VOR/DVOR (Very high frequency Omnidi- real exciting field is applied.
rectional Range; Doppler-VOR). These de- Worst case principles may be applied as an
tails comprise as an example (see for more example for the dielectric blades by assuming
details Fig. 3) the metal material.
· the correct geometrical and electrical set-
ting and numerical installation of the ac- Great care and knowhow has to be applied
tual system in the pre-processing section when carrying out these sophisticated meth-
· the signal processing, the filtering, the ods and interpreting the results in each case,
sampling, and the receiving antennas in because each of the methods can fail in
the post-processing section. certain situations /12/. Conclusions on the
Other field quantities (e.g. "field distortions") basis of incorrect results can yield a waste of
cannot describe in general sufficiently the money or can be the reason for hardly ac-
system effects. "Field distortions" are neces- ceptable, in fact unnecessary consequences,
sary effects for system distortions, but are such as the closure of a taxiway for A380
not a sufficient parameter to quantify the taxiing /12/.
system distortions.
The verification of the correctness and the
reliability of the system results is a particular PRACTICAL PROBLEMS
challenging task as discussed in /12/. A sin- The A380 on Airports and ILS
gle or “some measurements” are not suffi- The future A380 is currently the largest civil-
cient. Each result has to be verified in princi- ian aircraft (Fig. 5,7) which will appear in
ple. some years on the airports. Compared to the
other large aircraft, this aircraft has a maxi-
Fig. 4 shows the overall flow-chart of the mum height of the tail-fin of 24.1m. Due to
applied IHSS (Integrated Hybrid System the horizontal polarization of the ILS-fields the
Simulation). The best suited numerical higher parts of the aircraft may have stronger
method is taken for the particular problem, effects compared to the lower parts.
i.e. the A380 and the windgenerators. In However that does not mean that the tail-fin
2/12Paper ISPA2004 (Intern. Symposium on Precision Approach and Landing), Munich 10/2004
can describe the total aircraft sufficiently. · type and characteristics of antennas
Generally speaking, the larger and higher (medium, wide aperture, capture ratio,
the aircraft, the larger the distortions for the pattern shape, sidelobe suppression etc.)
ILS-subsystems. Therefore, the largest cur- · existing distortions by stationary objects
rently existing (military) aircraft (AN225; Fig. (hangars etc.)
5) will not have necessarily the largest DDM- · structural details of the layout of the air-
distortions. port (e.g. length of the runway)
The A380 will be by nature on an airport in · topological details of the runway or air-
several operational phases and by that in port, such as humped runways
quite a number of relevant positions and · operational category CATI-III
orientations (Fig. 6), such as : · type of the aircraft
· landing, rolling out, taxiing, parking, · single or groups of aircraft (e.g. when
starting queuing for takeoff)
· on parallel or sometimes inclined taxi- · type of receiving antenna in the aircraft or
ways in relation to the Localizer and/or to used for ground measurements.
the glidepath The setting and installation of the ILS-anten-
· rolling off after landing nas as well as the receiving antennas do
· rolling on for starting have a great impact on the results. Simple
· crossing the runway on taxiways in dif- unrealistic dipoles, adapted antennas (e.g.
ferent angles R&S HE108) or 3 element Yagis will show
· taxiing behind the Localizer and/or be- very much different DDM-results /1,6,9/ and
hind the glidepath would result in quite different safeguarding
· starting and flying over the Localizer areas or holding lines. It is problematic to
while not precisely above the runway compare measurements results for verifica-
centerline tion purposes and also to compare different
The international specification ICAO Annex results of simulations when the boundary
10 defines the DDM-tolerance limits for each conditions and the underlying numerical
operational category. The signal in space methods are not sufficiently known.
must meet these specifications when a lan-
ding aircraft is using ILS. The provider has The minimum separation between successive
to guarantee the compliance with these landing aircraft is also a function of the
specifications and has to take measures for preceding rolling-off aircraft or of the starting
that. aircraft. It is a well-known effect that large
As a matter of practical handling this basic DDM-oscillations occur when an aircraft is
task is met by the following safeguarding lifting off and flying over the ILS-Localizer
zones and lines which serves the signal for the next aircraft in
· critical areas (forbidden to enter for all the landing sequence. Unlocks or discon-
vehicles and aircraft; technically speak- nects of the autopilot may occur.
ing small objects may enter in certain ar- It is obvious that only a large number of tedi-
eas except the nearfield monitor area. A ous simulations for the particular case and at
verification is recommended by adequate a given airport for a certain ILS can yield the
methods.) required results. The providers and in par-
· sensitive areas (controlled access pos- ticular the airports are highly interested to
sible; e.g. for not too large vehicles and have the minimum size of the safeguarding
small aircraft; verification recommended) areas without increasing the risk for unspeci-
· holding lines . fied ILS-signals and reducing the safety.
These zones and lines have to be redefined
for the A380 aircraft. The sizes of these The Figures 8 and 9 show two examples of
zones or the distances of the holding lines to simulations from a methodological point of
centerline or on the taxiways depend on a view
number of factors which have to be taken · A380 on a parallel taxiway for a medium
into account, such as aperture Localizer antenna. The nose of
· type of system (single/dual frequency; the A380 is assumed to be in the xy-co-
installation of out-of-phase clearance ordinates, the axis is parallel to centerline.
(/1/) Filtered DDM-data are presented. DDM-
isolines are marked. From such results
the lateral extension of the safeguarding
3/12Paper ISPA2004 (Intern. Symposium on Precision Approach and Landing), Munich 10/2004
areas can be defined taking into account
the locus of the maximum DDM and the The WG are highly 3D-structures and need
related maximum tolerance limits at this an equivalent modeling (Figure 13). Typically
point. the shaft is a shaped metal tube or strongly
Holding points result from similar simula- reinforced concrete. The cover of the gen-
tions where the aircraft is inclined ac- erator house and the rotor blades are usually
cording to the angle of the rollon taxi- made of glass-fibre material. The blades
ways. have an integrated metallic lightning protec-
It is noted that the safeguarding areas tion system. However, the total structure has
("critical, sensitive areas") cannot be de- been modeled for the "worst case" to be fully
fined on the basis of the maximum DDM- metallic, i.e. by a large number of metallic
limits. Some margin for existing distor- triangles. This takes into account envi-
tions, stationary objects and superposing ronmental conditions. In principle the mod-
aircraft has to be provided. Also, the eling strategy is identical for the A380 and the
DDM-distortions increase drastically windgenerators.
when the aircraft is positioned in an in- For the VOR/DVOR systems the scattered
clined orientation to the centerline. This field components are superposed and proc-
is operationally the case when the air- essed appropriately, yielding the decisive
craft is turning towards the runway on the system parameter, i.e. the bearing error. The
rollon taxiway. field distortions of the VOR/DVOR-field in
· A380 rolling off on a high speed taxiway. itself are not a measure for the bearing errors
Time dependant DDM-data are pre- and system distortions. Fig. 11 shows such
sented. From these results the longitudi- kind of field distortions on a horizontal plane
nal extension of the critical area can be in 3D-representation. The largest field
defined. distortions are behind or beyond the
In both cases large DDM-distortions are en- windgenerator, but the bearing errors are
countered under the given circumstances. minimum in this region. Potential "shadowing
effects" are negligible for realistic distances of
the windgenerators to the VOR/DVOR-
The windgenerator and navaids systems station. The acceptable bearing errors are
Windgenerators (WG, "windmills", "windtur- defined in ICAO Annex 10 and in the flight
bines") are constructed more and more in inspection manual DOC 8071. The bearing
major quantities as a single installation or in errors have to be simulated at the lowest
large arrays ("windparks"). Often these ob- height of the coverage volume defined for
jects are close to navigation stations or in the each VOR/DVOR. Figure 12 shows an
coverage volume of radars of various types. example where the VOR/DVOR bearing
The advanced analysis of the effects of errors have been calculated on a horizontal
these WG on the navigation and radar sys- plane (100km*100km) at a height of 3300ft
tems is of increasing interest. The different MSL for a large windgenerator.
nature and function of the navigation sys- In this 2D-result for a defined height, all radi-
tems and radar suggest that the simulation als in that height are contained up to about
also must be quite different. However, the 50km. It can be clearly seen that the maxi-
introduced IHSS (Figure 4) and its imple- mum bearing errors of the DVOR are much
mented features allow the adapted analysis. smaller compared to the VOR.
Extensions in the pre-processing part and in
the final post-processing part had to be inte- Doppler spectrum
grated. This is especially true for the analysis The scattered Doppler-frequencies depend
of the Doppler-shift characteristics of a turn- on the radial velocity of the scattering objects
ing windgenerator (Fig. 10 and 13). The (Fig. 10 right). This fact has been used to
Doppler shifted scattered fields may have define a method for the calculation of the
adverse effects on the VOR/DVOR-system Doppler-spectrum of the reflected/scattered
because these systems evaluate 30Hz am- field.
plitude and 30Hz frequency modulations. In a side study it has been evaluated that the
This frequency can easily be produced by bearing error of a 30Hz Doppler-shifted
the fast turning blades (Fig. 10 right) even at component is larger by factors compared to a
the VHF ILS/VOR-carrier frequency of about non-shifted component. By that, the su-
110MHz. perposed amplitude of the 30Hz shifted
4/12Paper ISPA2004 (Intern. Symposium on Precision Approach and Landing), Munich 10/2004
component at some field point yields the horizontal plane in some minimum coverage
potential bearing error. height. The Doppler spectrum of the
It can be easily understood that for the turn- windgenerator has been discussed with re-
ing blades, the Doppler spectrum must be spect to the VOR/DVOR. A numerical result
symmetrical in principle around the un- has been presented showing the time variant
shifted zero line caused by the stationary spectrum of small amplitudes for several
subparts of the windgenerator, i.e. the shaft blade positions.
and the machine house.
Fig. 13 shows such an example of the Dop-
pler amplitude spectrum of a windgenerator REFERENCES
in some geometrical configuration. The Not all references are explicitly cited in this paper. The
spectrum is calculated and plotted for sev- references are sequenced according to the time of
eral angular positions of the blades. It can appearance.
be seen and understood that the spectral /1/ GREVING G. ILS CATIII site problems - A new
verified system solution, 7th Intern. flight inspection
amplitudes for a certain frequency are time
symposium, London 1992, p.224-236
periodic and time dependant. The ampli-
/2/ GREVING G. Computer aided site analysis and site
tudes are small compared to the static zero- adapted installation - Efficient commissioning of landing
line. The results so far indicate that this systems, 8th IFIS International flight inspection
Doppler-spectrum does not seem to be a symposium, Denver USA, June 1994
problem for the VOR/DVOR . /3/ GREVING G. Numerical system-simulations in-
cluding antennas and propagation exemplified for a
radio navigation system, AEÜ, Inter, J. of Electronics
and Communications, Vol. 54 (2000) No.3, pp. 183-189
CONCLUSION
/4/ GREVING G. Hybrid-Methods in Antennas and
Large objects close to navigation, landing 3D-Scattering for Navaids and Radar System Simu-
and radar systems can distort the electrical lations; Antenna and Propagation Conference AP2000,
April 2000, Davos Switzerland
characteristics of these systems. The new
/5/ GREVING G. Recent Advances and New Results
large aircraft A380 will appear relatively soon of Numerical Simulations for Navaids and Landing
on the airports. An increasing number of th
Systems, 11 IFIS International Flight Inspection
windgenerators are constructed often close Conference, Santiago Chile, June 2000
to these systems. /6/ G. GREVING, N. SPOHNHEIMER Problems and
The numerical 3D-treatment using "state-of- Solutions for ILS Category III Airborne and Ground
the-art-principles" of these objects has been Measurements - European and US Views and Per-
th
spectives, 11 IFIS International Flight Inspection
outlined and contrasted to simplified 2D- Symposium, Chile 2000, Proc. pp. 51-62
approaches. /7/ GREVING G. Application of Modern Numerical
A380 aircraft will be present in many differ- Methods for Navaids and Landing Systems - Theory
ent positions, in many orientations and op- and Results, ISPA 2000, International Symposium on
erational phases on the airports. Safe- Precision Approach and Landing, DGON, Munich, Proc.
guarding areas ("critical and sensitive ar- pp.49-61
eas", holding lines) have to be defined and /8/ GREVING G. Latest Advances and Results of
Complex Numerical Simulations for Navaids and
installed to protect the ILS. The case of the Landing Systems, 12
th
IFIS International Flight In-
"parallel taxiway" is a relatively simple case spection Symposium, Rome/Italy 2002, Proc. pp. 152-
in terms of the amplitudes of the DDM-dis- 162
tortions. Some principle results for the A380 /9/ G. GREVING, N. SPOHNHEIMER Problems and
have been presented, one for a parallel taxi- Solutions for Navaids Airborne and Ground Measure-
th
way and one for the dynamic rolloff case. As ments – Focus on receiver Sampling and TCH; 12
IFIS International Flight Inspection Symposium,
expected, these results and further results Rome/Italy 2002, Proc. pp. 90-99
show that the ILS-distortions by the A380 are /10/ G. GREVING, H. WIPF Flight Inspection Aircraft
remarkably larger than for the B747. By th
in Multipath Environment; 12 IFIS International Flight
systematic simulations for the individual Inspection Symposium, Rome/Italy 2002 Proc. pp. 198-
situation on a given airport the adapted and 207
minimized safeguarding areas can be de- /11/ GREVING G. Status and experiences of advan-
termined. ced threedimensional system simulations for navaids
and radar, Aviation World Conference, Kiew/Ukraine,
The numerical treatment of the windgenera- September 2003, pp. 5.1-5.5
tor with respect to a VOR/DVOR navigation /12/ GREVING G. Advanced Numerical System
system has been outlined. Some principle Simulations for Navaids and Surveillance Radar - The
results have been presented, showing the th
Verification Problem, 13 IFIS, June 2004, Mont-
bearing errors for a large windgenerator on a real/Canada, pp.173-186
5/12Paper ISPA2004 (Intern. Symposium on Precision Approach and Landing), Munich 10/2004
buildings, hangars, cranes, MoM layout, system position, safe-
aircraft, tanks, towers, fences, guarding areas, holding points,
high voltage lines, ... grading, earth movement, ...
A380
PO/IPO
PE C
L
ay
pe d runw
hum
DVOR/DME
ILS LOC
MLS Az,PDME
GO/GTD/UTD
ILS GP
MLS El
hybrid_11.dsf
not scaled
ASR/SSR windgenerator
Fig. 1: Sketch of an airport, humped runway, the subsystems of an ILS and MLS, some dis-
torting objects and a landing aircraft
Fig. 2: The large A380 aircraft and windgenerators pose a potential threat to all introduced
classic and modern navigation, landing and radar systems
6/12Paper ISPA2004 (Intern. Symposium on Precision Approach and Landing), Munich 10/2004
ispa04sota.dsf 10/04
"State-of-the-art" system analysis
reality model numerical method
MoM, ,...
3D ML-FMM, GTD/UTD, PE, PO/IPO
geometrical, electrical aspects "tool", math engine
3D, curved surfaces "reflections, scattering"
materials
field excitation best adapted for the model/reality
(amplitude, phases) least approximations
finite distances most advanced
as realistic as possible best approved/verified
as realistic as needed highest accuracy promising
no compromise for speed
latest scientific results
m
te
s
Sy
IHSS
Integrated Hybrid System Simulation
Fig. 3: General process flow and aspects for the modeling and the numerical treatment of the
A380 and the windgenerator
System
inthybsim4c.dsf
The real life problem, System + Environment - in advance
airport, enroute; ILS-LOC/GP, VOR/DVOR, MLS, DME/TACAN, ASR,SSR, weather radar, comm ...
pre-processing
Landing Systems,
Navaids, Radar
Theoretical analysis - Selection process
Modeling
system related pre-processing, modeling, approximations
data bases Hybrid
A/C,cranes,materials,...
combinations
Numerical Methods
GO/GTD/UTD MoM, wire/patch ML-FMM PE PO, IPO, EPO Antennas,
medium objects, aircraft,
large objects, ground, ... cranes, aircraft ... convergence? humped runways, ...
windmills, ... scattering objects
Multilayer, Green
ground effects,
snow,rain,glas, ... wave propagation
Details Superpositions
System Post-processing
Filtering, sampling, RX-antenna, ...
System
post-processing
System results, System parameter
Annex 10; DDM, bearing error, mod%, PFE,CMN , System
proposals, actions design,installation
range error, monopulse error, false target, ... parameter
Fig. 4: Process flow of the IHSS (Integrated Hybrid System Simulation)
7/12Paper ISPA2004 (Intern. Symposium on Precision Approach and Landing), Munich 10/2004
Comparison of Sizes
AN225 / A380 / B747
Height=18.2m Numerical 3D-models
Length=84m
Height=24.1m
Span=88.4m
AN225
Length=78.9m
Height=
19.4m
A380-800 Span=79.8m
Length=70.7m
a380c747an225.dsf 10/04
Span=64.4m
B747-400
Fig. 5: Numerical 3D-models of 3 large aircraft AN225, A380-800, B747-400; size comparison
A380 aircraft in various positions and orientations on the airport
a380casa1.dsf 10/04
D1
d starting crossing GP
LOC GP
holding D2
points d D3
landing, roll-out,
exiting rolling on
taxiing on parallel TWY
Fig. 6: The A380 aircraft on airports (runways, taxiways, landing, starting) with regard to ILS
(Localizer LOC, glidepath GP)
8/12Paper ISPA2004 (Intern. Symposium on Precision Approach and Landing), Munich 10/2004
Analysis by the IPO-method
Basic Dimensions:
improved and extended PO :
length = 78.9m span = 79.8m height = 24.1m (modified) basic PO-currents
37054 triangular patches (110MHz) + rim currents
+ Fock currents
+ shadowing effects
tail fin
3D-geometry composed of canonical
structural elements subdivided into
triangles
Fig. 7: Numerical 3D-model of the aircraft A380-800 consisting of 37054 triangular metallic
patches at 110MHz (ILS Localizer). A reduced number of triangles is displayed.
loca380w137f.dsf 09/04
Max. DDM (CAT III) on RWY (LOCALIZER)
|DDM| [mA]
100 THR (x/y): 4350 / 0
LOCALIZER (x/y): 0 / 0
Antenna: THALES 13/7
Y [m]
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Sensor: R&S HR-108
0
LLZ 1 THR
1
-100
4
8
10 1 10 7
4312
106
6
8
54 15 4 3
11
3
3
-200
2
3 7 9 8
2 6
1
1 2
1
5
-300 4
position of A380 (nose)
INDEPENDENT with highest DDM values
SCALE !
filtered data A380 rotation: 0 deg on RWY-CL at x=350...4350m
(height above RWY: 4m)
-400
0 500 1000 1500 2000 2500 3000 3500 4000
X [m]
16.09.04
loca380w0f13
Fig. 8: DDM-distortions on the runway for CATIII applications of an A380 on parallel taxiway;
medium aperture dual frequency Localizer; Filtered data; R&S HE108 RX antenna
9/12Paper ISPA2004 (Intern. Symposium on Precision Approach and Landing), Munich 10/2004
DDM distortions on glidepath
with moving A380 from centerline to fast roll-off taxiway abroll2_a.xls
15
LOC-antenna: 21/7
distance LOC-THR: 4260m
norm factor Clr/Crs: 0.03 / 0.022
10 method: IPO
5
4 Samples / sec
0
DDM / mA
-5 8000
po
1000
30
(lef sition
point "A"
time vs position of A380
t sc of fly
ale ing
)
distance of flying aircraft to THR / m
a ircra
ft 25
800
6000 covered way of A380 / m t=4
-10
v=3 /h
(con 00 km km t) 0s
stan /h 60 tan
angle of A380 / deg
t) v= ons
20
ec
(c
200
e)
600
rlin
t= 3
nte
150 0s
ce
4000 0 15
ec
= p cale 80
8
A3
to
-15
0 ° ht s of A3
of
ara )
llel
ay
Y/m
dw ) 400 100
re ale t=2
(rig gle
ve sc 0s
co ght 10
an
(ri ec
50 t=1 0 sec t=0 sec
2000
200 5
-20 0
4 .1 0.0 4
0 200 300 400 500 600 700 800 900 abroll3b
8.10.04
0 abroll2 0
0 5 10 15 20 25 30 35 40 45 distance from LOC / m
Time / sec
-25 abroll2
0 5 10 15 20 25 30 35 40 45
time / sec
Fig. 9: Time dependant dynamic DDM-distortions by an A380 when rolling on a fast-roll-off
taxiway; The landing aircraft is on the glidepath and moving also.
Windgenerator 6119 Patches / 110MHz ILS/VOR Windgenerator
ca. 130-150m
ca. 100-133m
Vestas V80 2MW 499291 Patches / 1030MHz SSR 12482 Patches / 110MHz ILS/VOR
Enercon E66 1088080 Patches / 1030MHz SSR
3D-model ca. 4Mio Patches / 3GHz PSR
1.8/2MW
3D-model
time variant scatteringPaper ISPA2004 (Intern. Symposium on Precision Approach and Landing), Munich 10/2004
DVOR fieldstrength on a plane
DVORfield1.dsf 07/04 horizontal plane in 2000ft above ground; 40km*50km
dB wind generator
-26
-30 100
-34
80
-38
-42 60
Z/m
-30 -46
-50 40
-54
-58
20
-40
-62
-20 0 20
-66 Y/m
Z / dB
-50
-60
DVOR reflector position
(X/Y/Z): 0 / 0 / 4.4
OR wind generator at (X/Y):
DV 2000m / 0m
0
or
r at
azimuth rotation angle: 0°
e ne -70 rotor: 0°
dg
-20
flat terrain
win 20 -10 frequency: 110 MHz
DVOR reflector diameter: 30m
0
X= 29.04.04
zapel2
Y/
km 40 10 k m 0
X/
20
line of maximum field distortions, but
minimum DVOR bearing errors
Fig. 11: Distorted field of a DVOR on a horizontal plane caused by a nearby windgenerator
DVOR with rotating wind generator
windspekt.dsf 10/04
Spektrum at (x/y/z): -25km / 25km / 2000ft - blades only (at point of maximum Doppler shift)
-90
wind generator wind generator
blades only blades only
-100 speed: 18 x min
-1
2020 0°
120 0° 30° 30°
-110 60° 60°
100 2000
90°
Z /m
from windgenerator
X /m
-120 80 90°
1980 without blades
dBV /m
-130 60
1960
40
-140 40 20 0 -20
Y/m
-40 -60 20 0
Y/m
-20 -40 band width: 1Hz
-150
-160
-170
-180-50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50
Doppler Shift / Hz
Fig. 13: Simulated Dopplerspectrum for VOR/DVOR-frequency of the rotating blades in diffe-
rent angular positions
11/12Paper ISPA2004 (Intern. Symposium on Precision Approach and Landing), Munich 10/2004
VOR station - bearing errors by E70
ispa04vordvor.dsf 10/04
horizontal plane 100km*100km, 3300ftMSL
50 Fehler / Grad Enercon E70
Dra ufsicht (Drehwinkel: 3 09° )
9
R 250
VO
40 4 240
2
X/m
230
1 220
30 0.4 210
1360 1340
0.2°
0.2 Y/m
20 0.1 Enercon E7 0
30
0 140
1. 7 120
°
10 100
80
Z
X / km
60
40
0 20
WKA 0
200 250 30 0
Y
11
6. 9
-10 °
309°
angle
ut h 10°
azim rror VOR Antenne:
WG earing e
j0°
-20 Loop 1 bei z=3.60m U=1Ve -j15°
1 59
b Loop 2 bei z=5.11m U=0.71Ve
max
.1°
Freq.: 111.2MHz
VOR bei (X/Y): 0 / 0
WKA bei (X/Y): 228m / 1351m
-30 WKA (E70) Nabenhöhe: 115m
Azimutaler Drehwinkel der WKA: 309°
(Bild rechts oben)
-40
11.8.04
-50 allersb_vor7d
40 30 20 10 0 -10 -20 -30 -40 -50
Y / km
DVOR station - bearing errors by E70
horizontal plane 100km*100km, 3300ftMSL
50 Fehler / Grad Enercon E70
Draufsicht (Drehwinkel: 309 °)
O R 0.7 250
DV
40 0.4 240
0.2
X /m
230
0.1 220
30 0.04 210
1 360 13 40
0.2°
0.02 Y/m
09°
20 gle 3 0.01 Enercon E70
imu th an r 0.72° 0
z ro
30
WG a earing er
140
1 .7
b
120
°
10 max 100
80
Z
X / km
60
40
0 20
WKA 0
200 250 300
Y
11
6.9
-10 °
-20
1 59
DVOR Antenne:
.1°
Reflektordurchmesser: 30m
Reflektorhöhe: 4.4m über Boden
Antenne: 1.2m über Reflektor
-30 Freq.: 111.2MHz
DVOR bei (X/Y): 0 / 0
WKA bei (X/Y): 228m / 1351m
WKA (E70) Nabenhöhe: 115m
-40 Azimutaler Drehwinkel der WKA: 309°
(Bild rechts oben)
11.8.04
-50 allersb_vor7e
40 30 20 10 0 -10 -20 -30 -40 -50
Y / km
Fig. 12: VOR/DVOR bearing errors caused by a windgenerator type Enercon E70; identical
geometrical configuration. Some used radials are marked. Note the different color coding of the
bearing errors
12/12You can also read
