# Review and Simulation of Counter-UAS Sensors for Unmanned Traffic Management
## 4 Counter-UAS Simulation Results  
The previous models have been implemented and integrated in the simulator described in [3]. This integration allows us to use the proposed models in realistic drone scenarios to assess and compare the performance of different sensors. Particularly, a scenario is proposed in this section where an area of interest (i.e., a critical facility) is to be surveilled with different C-UAS sensors. The simulated scenario is represented in Figure 3, where the area of interest to be protected is depicted in red. A surveillance solution using radars and eventual microphone sensors is proposed. This solution is complemented with the microphone sensor that works in shorter distances. The proposed sensors (depicted as markers in Figure 3) are:  
* **Quasi-monostatic Radar** (also named Active Radar in figures): A quasi-monostatic radar has been installed in the middle of the critical infrastructure with a quasi-monostatic configuration. The values taken to model the sensor refer to some of the commercial radars detailed in the state-of-the-art section. The radar has an instrument range of 10 km, a minimum azimuth of \(-180^{\circ}\) and a maximum of \(180^{\circ}\), 32 receiving beams and 10 m resolution. The average power transmitted is 500 W. The minimum time between explorations is 0.06 sec (the dwell time). The minimum frequency is 8 GHz, and the maximum frequency is 12 GHz. Finally, the reception beamwidth in azimuth is \(2^{\circ}\), and the beamwidth in elevation is \(6^{\circ}\). * **Passive Radar**: A passive radar is also installed in the center of the protected facility. It works in conjunction with a hypothetical transmitter of opportunity (i.e. : DVB-T transmitter) located at around 20 km from the passive receiver. The transmitter has enough power to support an instrument range of around 10 km. The minimum azimuth is \(-30^{\circ}\), and the maximum is \(30^{\circ}\). The resolution in distance is about 20 m, and the resolution in azimuth is \(2^{\circ}\). A scan time of 1 second has been assumed since it is a system with simultaneous space exploration without mechanical antenna movement. The antenna has a gain of 2 dBi, a secondary lobe level of 22 dB and a signal cancellation level of 60 dB. Finally, the carrier frequency is 600 MHz. * **MIMO Radar**: A MIMO radar is also installed in the critical infrastructure. It has the following instrumental coverage (minimum azimuth: \(-180^{\circ}\), maximum azimuth: \(180^{\circ}\), maximum range: 10 km): It is a medium/short surveillance system with one receiver (located in the center) and three transmitters (located in the area perimeter), which receive simultaneously through 32 receiving beams. The power transmission of each transmitter is 2 kW. The maximum scan rate is 1 s. The resolution in distance is about 20 m, and the resolution in azimuth is \(3^{\circ}\). The antenna has a gain of 11.6 dBi, a secondary lobe level of 13 dB and a signal cancellation level of 40 dB. Finally, the carrier frequency is 15 GHz. * **Microphone sensor**: A microphone sensor is also simulated in this scenario located in the center of the critical area. It is an array composed by eight microphones separated 0.5 m from each other. The sensitivity of the array is 32 dB, and it has an instrumental range of 1 km. The minimum azimuth of the sensor is \(-180^{\circ}\), and the maximum azimuth is \(180^{\circ}\). Although not frequent, violent and hostile acts against critical infrastructures have already occurred and are documented. The scenario tries to assess the alert distance in case of an aerial attack and the positioning accuracy provided by each of the sensors in the described surveillance system. The simulated attack is to be conducted by a terrorist group that intends to infiltrate by air using an off-the-shelf, affordable, and small drone such as a DJI Phantom 4 (estimated RCS of 0.01 m\({}^{2}\) and a noise level of around 80 dB). The departure place is located around 7 km away from the critical infrastructure.