الفهرس 
Chapter 1: IntroductionOnly 14 pages are availabe for public view
 |  | from | 90 |  |  |
| | | from | 90 | | |
Abstract
The assaulting jet fighters pose serious risks to both military and civilian lives, property, and establishments. Air defence systems must use both active and passive surface-to-air-launched homing missiles to counter such threats. When these jet-fighter attackers are navigating, especially with today’s advanced maneuvering capabilities, the task of intercepting them becomes considerably more difficult. A homing missile system’s three main objectives are to locate the target, follow it, and then detonate when it is intercepted. Huge amounts of infrared (IR) radiation are released along with the heat. from the jet fighter’s engine, by determining the path of the attacking jet fighter, a heat-seeking missile can track it.
The current work proposes a new signal processing approach for the on-board radar of active and hybrid homing missiles to identify jet fighter targets. An interior signature function for the suggested target identification technique is built using the frequencies of the internal resonances of the cavity-backed apertures that serve as the jet engine’s air-inlet pipes for a particular target. The electromagnetic simulation is used to simulate the air-inlet pipe as an open-ended conducting cylinder with several radial-conducting blades positioned inside the cylindrical cavity near the open end in order to quantitatively describe and evaluate the suggested design. Using linear frequency modulation (LFM) to incorporate the frequencies in the band 1.0–2.0 GHz with high sweep precision, frequency chirping is used to create the transmitted radar pulse. The chosen frequency range is sufficiently broad to allow for the distinction of different jet fighter targets. The radar cross section (RCS) of the open-ended pipe model with internal blades is assessed using the CST® simulator in the frequency range of 1.0–2.0 GHz as a result of the incident chirped pulsed plane wave previously indicated. The suggested target identification method is applied computationally and mathematically to recognize various targets with various jet engine pipe dimensions. Using the suggested scheme, the impact of additive white Gaussian noise (AWGN) on the accuracy of the target identification decision is examined by computing the false alarm rate (FAR) and adjusting the signal-to-noise ratio (SNR). The numerical analyses demonstrate that the suggested approach is successful in making the right choice for target identification with FAR<10% for SNR≥12dB.
In order to detect and track attacking jet fighters that are maneuvering, the present work suggests a new arrangement for the IR detector array in hybrid (passive/active) homing missiles. When utilized to determine the direction of a moving target, the suggested infrared detector array responds relatively quickly. The suggested feedback system of the missile flight control employs microwave radar in conjunction with the IR detector array to prevent the spurious IR sources launched by the maneuvering jet fighters’ infrared countermeasure (IRCM) systems Additionally, a new guidance system for missile trajectory optimization is introduced in this paper. Particle swarm optimization (PSO) is used to optimize the missile trajectory in order to shorten the time needed to intercept the target. This results in trajectory control. Target escape is less likely with such trajectory modification, even for highly maneuverable jet fighters. The effectiveness of the suggested methods is illustrated through the presentation of numerical results.
By inducing false alarms from the jet fighter’s infrared countermeasure systems to cause the missile to deviate from its ideal trajectory, the stability of the suggested trajectory control system has been tested. It has been demonstrated that the proposed control can quickly restore the optimal trajectory.