Browsing by Author "Jahangir, Mohammed"

Now showing 1 - 6 of 6
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    Advanced cognitive networked radar surveillance
    (IEEE, 2021-06-18) Jahangir, Mohammed; Baker, Chris J.; Antoniou, Michail; Griffin, Benjamin; Balleri, Alessio; Money, David; Harman, Stephen
    The concept of a traditional monostatic radar with co-located transmit and receive antennas naturally imposes performance limits that can adversely impact applications. Using a multiplicity of transmit and receive antennas and exploiting spatial diversity provides additional degrees of design freedom that can help overcome such limitations. Further, when coupled with cognitive signal processing, such advanced systems offer significant improvement in performance over their monostatic counterparts. This will also likely lead to new applications for radar sensing. In this paper we explore the fundamentals of multistatic network radar highlighting both potential and constraints whilst identifying future research needs and applications. Initial experimental results are presented for a 2-node networked staring radar.
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    Development of a passive dual channel receiver at L-band for the detection of drones
    (IEEE, 2022-06-02) Griffin, Benjamin; Balleri, Alessio; Baker, Chris; Jahangir, Mohammed; Harman, Stephen
    Staring radars use a transmitting static wide-beam antenna and a directive digital array to form multiple simultaneous beams on receive. Because beams are fixed, the radar can employ long integration times to detect slow low-RCS targets, such as drones, which present a challenge to traditional air surveillance radar. The use of multiple spatially separated receivers cooperating with the staring transmitters in a multistatic network allows multi-perspective target acquisitions that can help mitigate interference and ultimately enhance the detection of drones and reduce estimation errors. Here, the development and experimental results of a passive, dual-channel, L-band receiver are presented. The receiver has been used to take measurements of both moving vehicles of drones in flight using a bistatic staring transmitter. An analysis of the receiver is presented using GPS is used to quantify the estimation performance of the receiver.
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    Investigating jammer suppression with a 3-D staring array
    (IET, 2017-10) Liu, J.; Balleri, Alessio; Jahangir, Mohammed; Baker, C. J.
    A 3-D staring radar operates by using a wide beam transmitter to illuminate the entire surveillance region and generates multiple receive beams using a 2-D static array that can be digitised at element level. The sensor achieves permanent search in all directions and harnesses the spatial, temporal and spectral domains to improve detection and discrimination of low observable, highly manoeuvrable targets in congested air space against strong non-stationary clutter. While the susceptibility of traditional scanning radars to jammers has been well researched, very little work has been carried out to assess the performance of 3-D staring radars in the presence of an interference source. In this paper, the response of a staring array radar to a jammer is modelled. Results are presented showing that by exploiting the persistent dwell time of the staring array, it is possible to achieve effective jammer suppression using null steering or similar techniques.
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    Optimal receiver placement in staring cooperative radar networks for detection of drones
    (IEEE, 2020-12-04) Griffin, Benjamin; Balleri, Alessio; Baker, Chris; Jahangir, Mohammed
    Staring radars use a transmitting static wide-beam antenna and a directive digital array to form multiple simultaneous beams on receive. Because beams are static, the radar can employ long integration times that facilitate the detection of slow low-RCS targets, such as drones, which present a challenge to traditional air surveillance radar. Typical low altitude trajectories employed by drones often result in low-grazing angle multipath effects which are difficult to mitigate with a monostatic radar alone. The use of multiple spatially separated receivers cooperating with the staring transmitters in a multistatic network allows multi-perspective target acquisitions that can help mitigate multipath and ultimately enhance the detection of drones. This paper investigates how varying the network geometry affects the estimation performance of a targets position and velocity in a multipath free scenario. The optimal geometry is found by minimising the trace of the Cramér-Rao Lower Bound (CRLB) of the Maximum Likelihood (ML) estimates of range and Doppler using the Coordinate Descent (CD) algorithm. The network estimation accuracy performance is verified using Monte Carlo simulations and an ML Estimator on the target parameter estimates.
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    Prototyping a dual-channel receiver for use in a staring cooperative radar network for the detection of drones
    (IEEE, 2021-07-02) Griffin, Benjamin; Balleri, Alessio; Baker, Chris; Jahangir, Mohammed
    Staring radars use a transmitting static wide-beam antenna and a directive digital array to form multiple simultaneous beams on receive. Because beams are fixed, the radar can employ long integration times to detect slow low-RCS targets, such as drones, which present a challenge to traditional air surveillance radar. The use of multiple spatially separated receivers cooperating with the staring transmitters in a multistatic network allows multi-perspective target acquisitions that can help mitigate interference, such as signal multipath, and ultimately enhance the detection of drones and reduce target parameter estimation errors. Here, the design of a dual-channel receiver prototype for use in a multistatic cooperative network is presented. Several measurements have been taken using the prototype receiver in a bistatic configuration to test and assess its performance.
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    Simulations of L-band staring radar moving target integration efficiency
    (IEEE, 2018-11-12) Gersone, Fabiola; Balleri, Alessio; Baker, Chris J.; Jahangir, Mohammed
    Aveillant Ltd has developed a staring L-band radar that deploys a static quasi-monostatic antenna in transmission and a static digital phased array on receive capable of generating multiple simultaneous beams. Because the antenna is not rotating, the radar can stare at targets and select long dwell times with no effect on the scan rate. High Doppler resolution can be achieved and used to detect small targets, such as drones, even in heavy clutter. Despite the staring array, targets moving with a variable radial velocity generate echoes with a time-varying Doppler frequency shift that limits the integration gain achievable with standard Fourier Transform based techniques. As a result, the number of pulses can be integrated remains limited to the effective coherent processing interval with a consequent suboptimal Signal to Noise Ratio (SNR). This paper presents the results of a set of simulations aimed at studying the integration gain efficiency of a staring radar of the type of the Aveillant Holographic radar for targets moving with a constant and non-constant radial velocity. The case of a target flying horizontally with respect to the radar boresight is investigated to show that compensation techniques can be potentially employed to maximise coherence on the target and the resulting integration gain.