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Ingegneria Dei Sistemi Marcello Davide Mannino US/CANADA/EMEA/JAPAN KOREA Area Manager Via Flaminia, 1068 - 00189 Rome Italy Phone: +39 06 33217 452 Fax: +39 06 33217 431 E-mail: [email_address] WindFarms and EM Analysis Workflow: Case Study Caraffa di Catanzaro SSR Radar
This activity started on 2003 with an engineering support activity for a wind-farm installer (SARAS). In this case the M.te Codi (SE Sardinia, Italy) site was selected: in this area is installed an important ATC primary and secondary radar
After this first experience other wind-parks analysis have been executed
In 2003 IDS granted a contract from EUROCONTROL for the assessment of the potential impact of seven additional wind-turbines in the Kehmen wind park close to Diekirch DVOR/DME (DIK VOR)
This work was carried out by means of the electromagnetic analysis functions of the AIRNAS/EMACS SW tool, which enabled the IDS analysts to compute the VOR/DME signal in space taking into account that the:
VOR equipment operates in the VHF band (114.4 MHz in the DIK case);
Environment around the Diekirch site which is characterized by complex and wide elements such as the terrain and the pylon.
In order to evaluate the WF impact on the SSR station, you may execute two
In this case in the SSR Wind farm Post Processing are considered only the WT parameters shown in “Technical Specification”. This means that for each WT will be evaluated a worst case RCS. This is a conservative analysis which is more faster than the accurate one. If the Fast Analysis states a Total False Target Probability lower than 0.2 % (which means that the WF will have no effect of the SSR equipment) than the Accurate analysis will certainly confirm this result and so isn’t strictly necessary. If the Fast analysis states that the WF may have effect of the SSR equipment, an Accurate analysis is required to confirm this result
SSR WF PP implemets the following tecniques in order to minimase false
ISLS ( Interrogator Side Lobe Suppression )
It is a technique used to suppress the transponder replays from the SSR side lobe interrogation. ISLS uses a beam with approximately circular radiation pattern in the horizontal plane (control pattern) in order to transmit the P2 pulse. The pulse P1 is transmitted by a beam with directional radiation pattern in the horizontal plane (sum pattern) in order to transmit the P1 pulse. The transponder replays only if the amplitude of the received P1 pulse is greater then the amplitude of the received P2 pulse.
IISLS ( Improved Interrogator Side Lobe Suppression )
IISLS technique is an improvement of the ISLS one. ISLS works only if the amplitude of the P1 pulse transmitted by the side lobes of the SSR sum antenna pattern has an amplitude sufficient to be detected by the SSR transponder. If this condition is not satisfied, the transponder can’t recognise the P1-P2 suppression pair.
IISLS is used in order to guarantee that the P1 pulse is recognised from the transponder. In IISLS pulse P1 is radiated from the control pattern as well as from the sum pattern. In this way the transponder can receive a P1 pulse of sufficient strength in order to recognise the P1-P2 pair and suppress the reply to side lobe interrogation. The main disadvantage of this technique is that all aircraft which are within the range of the control beam but outside the sum beam, have their SSR transponder in the suppression state and this can be inacceptable in environment where there are more than one SSR interrogator.