• Journal of Advanced Navigation Technology
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• v.19 no.2
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• pp.108-115
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• 2015

Multilateration systems are used to provide the position of aircraft in flight or on airport runways. In the multilateration systems, the interrogator is an important transmitter that used to interrogate the airplanes with appropriately scenario in surveillance airspace. Whisper-Shout interrogation sequence, which is one of the key functions of the interrogator, can control airport traffic density when intruder airplanes are coming into the surveillance airspace. Therefore collision chance between airplanes could be reduced and also get highly accurate location of incoming airplane in multilateration systems. In this paper, we developed the interrogator that allows it to transmit Mode A/C and Mode S interrogations which is similar to existing secondary surveillance radar. With appropriately controlled Whisper-Shout sequence in the interrogator, the multilateration systems can avoid synchronous garbling and FRUIT phenomenons caused by receiving multiple responses from a number of airplanes.

• Journal of Advanced Navigation Technology
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• v.21 no.2
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• pp.179-186
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• 2017

This paper is concerned with an interrogator capable of constructing a interrogation scenario for acquiring active airspace to the intruding aircraft into the surveillance area of the MLAT system. In the MLAT system, the interrogator is an important device used to carry out the interrogation towards the aircraft within the surveillance airspace in the appropriate surveillance scenario. Unlike a conventional SSR's interrogation methods that interrogate for airplanes flying within a certain range, the MLAT system requires a interrogation system that can actively interrogate from remote to near range, or according to operational scenarios, for aircraft intruding into the surveillance range. The interrogator implemented in this paper can be used for interrogating and monitoring aircraft within each surveillance airspace using whisper-shout algorithm according to varying output power based on the actual operation distance.