Modeling and Simulation of the Active Jammer Effect in the Crossed Array Detectors Infrared Seeker
IR active jammers or the directed infrared counter measures(DIRCM)generate IR signals which attack the guidance signals passed to the sensors in IR-guided weapons. They provide IR signals with appropriate frequency, phase and intensity which will be superposed on those produced by the IR energy of the target passing through the reticle. When both the jamming signal and the modulated target energy signals are received by the missile‟s IR sensor, they cause the tracker to produce incorrect guidance commands and push the target out of the field of view (FOV). In this paper, the seeker signals of a crossed four slits or crossed array detectors (CAT) infrared seeker will be simulated. Then the active jammer signal is modeled and simulated. After that, the effect of all the active jammer parameters will be discussed and simulated. Finally, the conditions or the ranges of these parameters in which the active jammer can affect the seeking process will be stated.
A review of the development of optical countermeasures
Optical countermeasures have been used for several millenia to provide a defensive capability capability. The fundamental approach is to use an intense optical source to dazzle a sensor or distract an operator or target tracking system causing a weapon to miss its intended target. The development of the laser has provided a stimulus for anumber of soft-kill weapon systems used to enhance platform survivability and anti-air missile applications; in this case the laser may cause dazzle, or if the beam is sufficiently intense it may cause damage. Laser technology is also crucial for an aspect of directed energy weapons. The various aspects of optical countermeasures are considered in this paper, including defeat mechanisms of active and passive techniques. The review includes a historical perspective through to prospects for the future.
Analysis of Error Response of Amplitude Modulated Reticles
A method is described for calculating the error response of optical-reticle systems used to convert line-of-sight angle into an electrical signal. The calculation is carried out in the frequency domain and relates optical aberrations as expressed in terms of a spot diagram, and the reticle pattern which is characterized by a reticle phase function, to the amplitudes and phases of the significant harmonics in the output waveform. The procedure is easily programmed for a computer and permits the rapid evaluation of reticle and optical designs and design changes.