نشریه دفاع هوافضایی
سال دوم شماره 1 (پیاپی 5، بهار 1402)

The advancement of technology and the use of modern and intelligent weapons has led to the creation of a more complex and destructive nature of weapons in possible future wars and has made it more necessary to pay serious attention to the application of passive defense measures against the threat factors of sensitive and vital centers, which in the research The present study, which is of an applied-developmental type and is carried out by a mixed method, the main issue, "what are the passive defense measures against the threat factors of radar systems in future wars" is considered and based on the studies and interviews conducted with experts, the number of 15/15 A threat has been identified in the field of radar detection systems in future wars and using new methods from the 14/14 principles of passive defense (camouflage and invisibility; concealment using natural effects; deception and initiative; coverage in all fields; miniaturization; blinding of information systems; choosing the optimal scale of dispersal; strengthening, fortifications and security; positioning of systems deployment; defense crisis management; dispersion in the distribution of radar stations; selection of safe areas; parallelization of systems and information protection) in order to improve the immunity of radar systems against these threats.

In this paper, the efficiency of the bedrock grain's characteristics on the performance of its layers was investigated. For this purpose, experimental and numerical studies were performed using ABAQUS software in both static and dynamic conditions. The performances of the geogrid layers in various types of soils by different values of elastic modulus and frictional angles were investigated. It was observed that increasing soil adhesion at a constant concentration, enhanced loading capacity, and reduced the reinforcing efficiency. Study on different soil types by various specifications showed that for soil substrates by values of elastic modulus of 10, 50 and 100 MPa, the effects of the layers of the reinforcement on improving the Settlement were about 75%, 65% and 54%, respectively. In dynamic loading mode, the performance of the reinforcement layers increased compared to static loading, and the improvements of the Settlement were 79%, 72% and 54%, respectively.

The use of broadband pulses in structures based on phase shift antenna arrays is difficult due to the Luchi beam phenomenon. Therefore, as an alternative method, structures based on the real time delay of photonic microwave technology are used, which increases the usable bandwidth. However, the use of conventional photonic microwave technology and the conditions related to its modulator, itself causes the limitation of bandwidth and pulse level. In this article, the performance of a real time delay structure has been improved by using a special type of optical fibers under the physical phenomenon of modulation instability, which increases the pulse power level and bandwidth. In fact, the performance improvement of a modulator with a single laser (carrier signal) was extended to the frequency comb mode.

The advancement of technology and the use of modern and intelligent weapons has led to the creation of a more complex and destructive nature of weapons in possible future wars and has made it more necessary to pay serious attention to the application of passive defense measures against the threat factors of sensitive and vital centers, which in the research The present study, which is of an applied-developmental type and is carried out by a mixed method, the main issue, "what are the passive defense measures against the threat factors of radar systems in future wars" is considered and based on the studies and interviews conducted with experts, the number of 51/51A threat has been identified in the field of radar detection systems in future wars and using new methods from the 51/51 principles of passive defense (camouflage and invisibility; concealment using natural effects; deception and initiative; coverage in all fields; miniaturization; blinding of information systems; choosing the optimal scale of dispersal; strengthening, fortifications and security; positioning of systems deployment; defense crisis management; dispersion in the distribution of radar stations; selection of safe areas; parallelization of systems and information protection) in order to improve the immunity of radar systems against these threats.

Automatic tracking systems of flying targets play a key role in the battle field. Nowadays, vision sensors have attracted wide attention due to their outstanding features such as being cheap, passive, and their resistant to jamming in comparison to expensive radar-based tracking system which prone to jamming. In this paper, a system is considered and designed for automatic tracking of flying targets using segmentation and digital image processing. In the first section, images of flying targets are proceed using color image segmentation algorithm through Kmeans and FCM clustering techniques and then desired target is detected. In following, edges of images are detected using Prewitt algorithm and then desired object is identified and tracked. Visual results of developed techniques are similar and have sufficient accuracy but, speed of automatic tracking using edge detection is higher in comparison to color image segmentation and so its performance in battle field and online tracking of flying targets is preferred.

In this article, we intend to address the issue of routing of flying objects such as drones, missiles, etc., using the proposed innovative algorithm. For this purpose, an innovative algorithm has been presented on a precise line that provides the best path without hitting obstacles to guide a flying object to intercept and reach the target. The environmental conditions are assumed in such a way that a flying object has no prior knowledge of the environment in which it is located, and it learns about its surroundings through the sensors embedded in it, which have a limited exploration area. Existing obstacles can be considered fixed or moving, and their movements are also unknown to the flying object, and they can also be of different geometric shapes. Finally, the flying object must reach a fixed target by which it can be reached. Also, the effectiveness of the proposed algorithm will be measured in the case that the flying object must avoid and pass through a security or forbidden space with a certain confidence interval.