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Obstruction Manager
1WRAP 0972E
Obstruction Manager
• Calculates the interference to radars caused by wind power stations and masts
2WRAP 0972E
Introduction
• Calculates the signal-to-interference ratio, S/I.
• The signal is the signal radar target radar
• The interfering signal is the sum of the signals:– radar target obstacle radar– radar obstacle target radar– radar obstacle target obstacle radar
• Compares the calculated S/I to the radar receiver required S/I.
3WRAP 0972E
Workflow
• The user inputs data for obstacles• For each new obstacle
– Check for aeronautical stations within 3 km from wind power stations (3.3 km for masts)
– Search for possible interfered radar stations within 100 km limit from obstacle
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Workflow (cont.)
– For each possible interfered radar station• Check forbidden area (limit 2 km)• Check if obstacle within interference free area
(limit 100 km in operational sector of radar)• Check if obstacle is visible from the radar• Search for existing obstacles in ObsMan and
FIA databases• Check if existing obstacles is affected by the
new obstacles• Check new obstacles (including possible
group effects)
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Wind power stationradar cross section
• The wind power station radar cross section is calculated in 3 different depending on the angle β.
• β = 0° is called backward propagation• 0°<β<180° is called subsidiary static propagation• β = 180° is called forward propagation
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RD
RI
ri
αβ
φ
Radar
Wind power station
Calculation point
Wind power stationradar cross section
• The wind power station radar cross section is highly dependent on vertical incidence angle
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Wind power stations, input window
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Mast parameters
Mast parameters• Mast height• Bottom width of the mast• Top width of the mast
• The radar cross section depends on the mast dimensions and the angle of incidence.
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Databases
The calculation uses three different databases:• FIA
– Aviation obstacle database. – Contains masts and wind power stations (read-
only).
• ObsmandB– Contains masts and wind power stations defined
in Obsman.
• WRAPdB– Contains radar stations.
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Terrain blocking
• The obstacle can be blocked by the terrain• The radar cross section is compensated
for the limited visibility
11WRAP 0972E
Wind power station
Radar
Calculation area
• The calculations are performed at points along aline 60 km from the radar. The length of the line are limited 2 x lobe width (3 dB)
• The resolution of the calculation points are the same as in the height database
12WRAP 0972E
60 kmRadar
κ
Calculation result
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Detailed calculation result
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Reports
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There are three different types of reports in the Obsman tool.• Answering letter• Summary of all the cases• Detailed report of a case
Answering letter
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Summary of all cases
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Detailed case report
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