Antenna aperture tapers for regulatory tradeoff

The results of modeling the processes of receiving and processing the signals of remote sensing of the Earth’s surface using helicopter radar and synthesizing the antenna aperture due to its placement on the rotating rotor blades are presented. The mathematical correctness of the application of the developed algorithms for processing probing signals, as well as the uniqueness of the measurements, was confirmed. At the same time, the dimensions of the synthesized aperture due to the rotation of the radiator placed at the end of the propeller blade are equivalent to a circular antenna array with a diameter of tens of meters. The functionality of the remote sensing system based on this radar meets the requirements for ice observation and navigation systems for seagoing ships off the coast. The simulation results confirm the promise of further research in this direction and can be used in the development of radar systems with synthesized antenna aperture mounted on rotating rotor blades.

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Impact of Various Parameters on the Performance of Inter-aircraft Optical Wireless Communication Link

Journal of Optical Communications ◽

10.1515/joc-2016-0112 ◽

2017 ◽

Vol 39 (1) ◽

Author(s):

Mehtab Singh

Keyword(s):

Wireless Communication ◽

Transmission Rate ◽

Power Level ◽

Communication Link ◽

Optical Wireless Communication ◽

Optical Wireless ◽

Antenna Aperture ◽

Aperture Diameter ◽

Pointing Error ◽

The Impact

AbstractOptical wireless communication (OWC) systems also known as Free space optics (FSO) are capable of providing high channel bandwidth, high data transmission rates, low power consumption, and high security. OWC links are being considered in different applications such as inter-satellite links, terrestrial links, and inter-aircraft communication links. This paper investigates the impact of different system parameters such as transmission power level, operating wavelength, transmitter pointing error angle, bit transmission rate, atmospheric attenuation, antenna aperture diameter, geometric losses, the responsivity of the photodetector, and link range on the performance of inter-aircraft optical wireless communication link.

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Microwave Holographic Surface Measurement of the Tidbinbilla 64-m Antenna

Publications of the Astronomical Society of Australia ◽

10.1017/s1323358000017082 ◽

1983 ◽

Vol 5 (2) ◽

pp. 270-272 ◽

Cited By ~ 2

Author(s):

Y. Rahmat-Samii ◽

S. Gulkis ◽

G.S. Levy ◽

B.L Seidel ◽

L.E. Young ◽

...

Keyword(s):

High Speed ◽

Survey Methods ◽

Low Cost ◽

Single Frequency ◽

Surface Measurement ◽

Antenna Aperture ◽

Phase Fluctuations ◽

Surface Deviations ◽

Antenna Surface ◽

Surface Figure

The ‘holographic’ technique for accurately measuring the surface figure of large reflector antennas, described by Bennet et al, (1976) and Scott and Ryle (1977), has many advantages over older conventional survey methods. These include high speed, low cost, and the absence of any need for additional complex mechanical or optical survey devices. In essence, the technique consists of measuring the complex far-field response of the antenna at a single frequency using a terrestrial, satellite-borne or celestial radiation source of small angular diameter. This two-dimensional pattern is then Fourier-transformed to yield the complex illumination function across the antenna aperture. Antenna surface deviations are manifested as phase fluctuations in this function. In practice, a second antenna is needed to provide a phase reference.

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Simulation of SAR signal processing system in telescopic mapping

Issues of radio electronics ◽

10.21778/2218-5453-2020-12-23-29 ◽

2021 ◽

pp. 23-29

Author(s):

K. B. Gurnov ◽

E. M. Izotova

Keyword(s):

Processing System ◽

Time Frame ◽

Antenna System ◽

Antenna Aperture ◽

Signal Processing System ◽

Radar Images ◽

Stage Of Development ◽

High Resolution Radar ◽

Sar Model ◽

The Cost

At the present stage of development of surveillance tools, the most popular are radar tools. A special place among such systems is occupied by radars with a synthesized antenna aperture, which make it possible to obtain high-resolution radar images with a relatively small size of the antenna system. The creation of such radar facilities has a number of features, which increases the cost of the development process and increases the time frame, and verification of work can be complicated by the inability to form the required conditions. To eliminate such difficulties, it is advisable to create adequate mathematical models of systems that would allow you to conduct all the necessary tests and work out algorithms, with minimal time spent. In this paper, a phenomenological model of the reflected signal in SAR is proposed, and a SAR model is developed that has a block structure and can be supplemented with modules to identify new dependencies.

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High performance radar images modelling and recognition of real objects

Information Technology and Nanotechnology ◽

10.18287/1613-0073-2019-2416-549-552 ◽

2019 ◽

pp. 549-552

Author(s):

D A Zherdev ◽

V V Prokudin

Keyword(s):

Parallel Algorithm ◽

High Performance ◽

3D Models ◽

Parallel Program ◽

Antenna Aperture ◽

Radar Images ◽

Scene Description ◽

Real Objects

In the work there is a modernization of the parallel algorithm for the radar images formation of 3D models with the synthesis of the antenna aperture. In the formation of the scene description, the various structures are used in which it is possible to use more efficient and derived calculations. In addition, it is the topical task to recognize objects on radar images. Thus, on the basis of the implemented parallel program for modelling, the high performance required for simulating multiple radar images can be achieved.

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MATHEMATICAL MODELS OF THE RADAR SIGNAL REFLECTED FROM A HELICOPTER MAIN ROTOR IN APPLICATION TO INVERSE SYNTHESIS OF ANTENNA APERTURE

Journal of the Russian Universities Radioelectronics ◽

10.32603/1993-8985-2019-22-3-74-87 ◽

2019 ◽

Vol 22 (3) ◽

pp. 74-87 ◽

Cited By ~ 1

Author(s):

Sergey R. Heister ◽

Thai T. Nguyn

Keyword(s):

Mathematical Models ◽

Vertical Plane ◽

Rotor Blades ◽

Radar Signal ◽

Main Rotor ◽

Antenna Aperture ◽

Radar Images ◽

Aerial Vehicles ◽

Propeller Blades ◽

Helicopter Main Rotor

Introduction. The basis for solving the problem of aircraft recognition is the formation of radar portraits, reflecting the constructive features of aerial vehicles. Portraits, which are radar images of the propellers of aerial vehicles, have high informativeness. These images allow us to distinguish the number and relative position of the propeller blades, as well as the direction of its rotation. The basis for obtaining such images are mathematical models of reflected signals. Objective. The aim of this paper is to develop mathematical models of the radar signal reflected from the helicopter main rotor applied to inverse synthetic aperture radar (ISAR). Methods and materials. ISAR processing is used to produce a radar image of a propeller in a radar with a monochromatic probing signal. The propeller blades in the models are approximated by different geometric shapes. The models used to describe the reflection from the propellers of helicopters and fixed-wing aircraft have significant differences. In the process of moving each blade of the helicopter main rotor makes characteristic movements (flapping, dragging, feathering), as well as bends in a vertical plane. Such movements and bendings of the blades are influence the phase of the signal reflected from the main rotor. It is necessary to take the phase change of the reflected signal into account as accurately as possible when developing an ISAR algorithm for imaging the main rotor. Results. We found that in the centimeter wavelength range the mathematical model of the signal reflected from the helicopter main rotor as a system of blades is most accurately described by representing each blade with a set of isotropic reflectors located on the main rotor’s blade leading and trailing edges. Taking into account the flapping movements and curved shapes of the blades in the model allows you to get as close as possible to the features of the real signal. Conclusion. The developed model which takes into account the flapping movements and bends of the helicopter main rotor blades can be used to improve the ISAR algorithms providing the radar imaging of aerial vehicles.

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Simulative Investigation on the Effect of Different Parameters on the Performance of IsOWC System

Journal of Optical Communications ◽

10.1515/joc-2016-0058 ◽

2017 ◽

Vol 38 (3) ◽

Cited By ~ 1

Author(s):

Mehtab Singh

Keyword(s):

Communication Systems ◽

Satellite Communication ◽

Communication Link ◽

Optical Wireless ◽

Antenna Aperture ◽

Aperture Diameter ◽

Pointing Errors ◽

Signal Degradation ◽

Communication Links ◽

Radio Frequency Signals

AbstractInter-satellite communication links are very crucial between satellites orbiting around the earth in order to transmit information between them and also for the purpose of data relaying from one satellite station to other stations and ground stations. Inter-satellite optical wireless communication (IsOWC) links involve the application of optical wireless signals as compared to radio frequency signals used in traditional satellite communication systems. One of the major problems leading to the performance degradation of IsOWC link is the signal degradation due to satellite vibrations also known as pointing errors. In this paper, the performance of an IsOWC communication link has been investigated for different system parameters such as data transmission rates, antenna aperture diameter, transmission power levels, operating wavelength and responsivity of photodiode by analyzing

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