1. Obstruction Manager 1 WRAP 0972E

2. Obstruction Manager Calculates the interference to radars caused by wind power stations and masts 2 WRAP 0972E

3. 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. 3 WRAP 0972E

4. 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 4 WRAP 0972E

5. 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) 5 WRAP 0972E

6. Wind power station radar 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 6 WRAP 0972E RDRD RIRI riri α β φ Radar Wind power station Calculation point

7. Wind power station radar cross section The wind power station radar cross section is highly dependent on vertical incidence angle 7 WRAP 0972E

8. Wind power stations, input window 8 WRAP 0972E

9. 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. 9 WRAP 0972E

10. 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. 10 WRAP 0972E

11. Terrain blocking The obstacle can be blocked by the terrain The radar cross section is compensated for the limited visibility 11 WRAP 0972E

12. 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 12 WRAP 0972E 60 km Radar κ

13. Calculation result 13 WRAP 0972E

14. Detailed calculation result 14 WRAP 0972E

15. Reports 15 WRAP 0972E There are three different types of reports in the Obsman tool. Answering letter Summary of all the cases Detailed report of a case

16. Answering letter 16 WRAP 0972E

17. Summary of all cases 17 WRAP 0972E

18. Detailed case report 18 WRAP 0972E