Obstruction Manager

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Obstruction Manager

• Calculates the interference to radars caused by wind power stations and masts

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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.

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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

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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

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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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