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.
Seeker-Azimuth Determination with Gyro Rotor and Optoelectronic Sensors
This paper presents an approach to seeker-azimuth determination using the gyro rotor and optoelectronic sensors. In the proposed method, the gyro rotor is designed with a set of black and white right spherical triangle patterns on its surface. Two pairs of optoelectronic sensors are located symmetrically around the gyro rotor. When there is an azimuth, the stripe width covering the black and white patterns changes. The optoelectronic sensors then capture the reflected optical signals from the different black and white pattern stripes on the gyro rotor and produce the duty ratio signal. The functional relationship between the measured duty ratio and the azimuth information is numerically derived, and, based on this relationship, the azimuth is determined from the measured duty ratio. Experimental results show that the proposed approach produces a large azimuth range and high measurement accuracy with the linearity error of less than 0.005.
New approach to vision-based BGA package inspection
Ball grid array (BGA) techniques have developed very fast due to the advantages of more I/O ports, small size, and so on. In this paper, a vision-based algorithm for BGA package inspection is proposed to accurately estimate center and diameters of solder-balls of BGA packages, so that defects of BGA packages, such as missing or extra balls, oversize or undersize balls, over-height or under-height balls, and pitch can be detected for ensuring the quality of BGA packages.