Aerial Target Research Articles

To a problem on formation of an optimal type of aerial targets

A two-criterion problem for optimal choice of aerial target types based on formal determination of a minimal coverage of simulated aerial objects by means of a great number of targets is proposed.

Infrared radiation measurement of the aerial target based on temperature calibration and target images

The gray level values of target pixels of infrared images processed by the SUSAN noise filtering algorithm and the background filtering algorithm are calculated, assuming that the target distance is given in image acquisition. The equivalent blackbody temperature is obtained by the temperature calibration model that represents the quantitative relation, at a certain integration time, between the gray level value and the equivalent blackbody temperature. The temperature calibration model has been acquired by the curve fitting with the experimental data of blackbody temperature calibration using Origin 6.0. Then the target radiance can be determined by the radiant flux equivalence model built on condition that the target radiant flux received by the infrared detector is equivalent to that of the blackbody placed in front of the infrared detector at a close distance. This measuring method is based on the temperature calibration parameters and real image information, so it can avoid subjectivity of the traditional theory modeling methods.

A probabilistic nearest neighbor filter algorithm for m validated measurements

The probabilistic nature of the nearest neighbor measurement in a cluttered environment is shown to be varying with respect to the number of validated measurements. Incorporating the number of validated measurements into the design of the probabilistic nearest neighbor filter (PNNF) produces a new data association proposed in this correspondence. The proposed algorithm for aerial target tracking in a cluttered environment is tested by a series of Monte Carlo simulation runs, and it turns out that the new filter has less sensitivity for the unknown spatial density of false measurements and better tracking performance than the existing PNNF that does not utilize the current number of validated measurements

Image-based analysis enables aerial target detection

Image-based analysis enables aerial target detection

Capture Conditions in a Pursuit-Evasion Game between Players with Biproper Dynamics1

Capture conditions in a planar pursuit-evasion game between a guided missile and its aerial target, each having either forward control or tail control, are derived analytically. The adversaries closed-loop maneuver dynamics are represented by first-order biproper transfer functions. A distinction is made between open and closed capture zones in the reduced-order game space. It is shown that locating the control surface forward, instead of aft, provides considerable advantages with regard to the existence and size of different capture zones. A new game space decomposition with two singular regions is also presented and the conditions for its existence are given.

Multi-aspect radar target recognition method based on scattering centers and HMMs classifiers

A hidden Markov model (HMM)-based method for recognizing aerial targets according to the sequential high-range-resolution (HRR) radar signature is presented. Its recognition features are the location information of scattering centers extracted from the HRR radar echoes by the relax algorithm. The HMM is used to characterize the spatio-temporal information of a target. Several HMMs are cascaded in a chain to model the variation in the target orientation and used as classifiers. Computer simulations with the inverse synthetic aperture radar (ISAR) data are given to demonstrate that for an open-set recognition, average class-recognition rates of 84.50% and 89.88% are achieved, respectively, under two given conditions.

A probabilistic nearest neighbor filter algorithm for tracking in a clutter environment

A new probabilistic nearest neighbor (NN) filter algorithm which accounts for the probability that the NN measurement is a false one is proposed to improve the performance of the NN filter. The NN filter is the most popular and widely used algorithm for target tracking in clutter due to its computational simplicity. The proposed algorithm is derived from establishing probability density functions conditioned on all the possible events related to the NN measurement. The resulting algorithm is different from the existing probabilistic nearest neighbor filter (PNNF) algorithm. The performance of the proposed algorithm is analyzed and compared with that of the NNF. The proposed algorithm for aerial target tracking in a clutter environment is tested by a series of Monte Carlo simulation runs. Simulation results are also compared with the off-line performance prediction algorithm developed in this paper.

A computer simulation of Desert Locust band target block detection and demarcation

Most Desert Locust control is carried out on bands of nymphs using aerial sprays. Ultra low volume control from the air demands a large target block containing a number of bands. A computer model has been developed to mimic search to find and mark control blocks either by vehicle and or by aircraft with various band distributions. The operator can choose values of some relevant variables. In a series of simulations proposed vehicle search methods proved to be either ineffective, or to require unrealistic assumptions or excessive resources in the simulation. Only aerial target detection and demarcation produced a satisfactory result. That is in accord with field experience for the Australian Plague Locust.

Computer simulation of aerial target radar scattering recognition, detection, and tracking

Aerial Target Scattering Simulation in Decimeter and Centimeter Wave Bands - Possible Simulation Methods. Simplest Component Method. Consideration of Fast-Rotating Target Components. Consideration of Target Flight in Various Weather Conditions. Informativity of Recognition Features. Simulation of Recognition Features in the Cases of the Wide-Band and Narrow-Band Illumination. Signals - Target Range Profile Simulation by Various Wide-Band Probing Methods. Range-Polarization and Range-Frequency Target Profile Simulation. The 2-D Target Image Simulation. Simulation of Radar Cross-Sections and Polarization Parameters, Rotational Modulation Parameters and Correlation Factors of Fluctuations via Frequency Diversity in Narrow-Band Illumination. Simulation of the Aerial Target Recognition Algorithm Operation -Bayesian and Nonparametric Recognition Algorithm Variety. Direct Utilization and Wavelet Transform of Initial Data. Neural Recognition Algorithms Variety and their Use in Recognition. Simulation of the Aerial Target Detection and Tracking Algorithm Operation .- Comparison of Simulated and A Priori Fluctuation Models. Target Glint Models in Tracking. The Wideband Detection and Tracking. Peculiarity of Simulation in Ground Clutter and Ground Reflection of Narrowband and Wideband Signals.- General Principles of Simulation. Digital Terrain Maps and Peculiarities of their Use in Simulation. Recognition in the Ground Clutter and Ground Reflection. Augmented Physical Optics Utilization in Simulation. Scattering Effects for the Targets Uncovered, Partially and Completely Covered with Radar-Absorbing Materials in Bistatic and Monostatic Radar. References. Index.

Modeling Millimeter and Centimeter Wavelength Fields over the Sea in the Analysis of Elevation Angle Estimation Methods for Low-Flying Aerial Targets

Modeling Millimeter and Centimeter Wavelength Fields over the Sea in the Analysis of Elevation Angle Estimation Methods for Low-Flying Aerial Targets

Noise and errors analysis and influences on target coordinates evaluation

This paper presents a mathematical model of analyzing the effects which noise and tracking errors have made during measurements of a target position while determining its coordinates. Here is also presented a procedure for computing errors in measuring a target position in the space comprised by measurements as well as for computing errors in predetermined directions of aerial targets movement. This approach has en extensive application in increasing hit probability of fire control systems, in improving the quality of target tracking system testing, and in the optimization of allocating antiaircraft defense systems.

Computer simulation of aerial target radar scattering, recognition, detection, and tracking [Book Review

Computer simulation of aerial target radar scattering, recognition, detection, and tracking [Book Review

Prey catching in the archer fish: angles and probability of hitting an aerial target

When trying to squirt down aerial arthropods, archer fishes (Toxotidae) have to cope with the displacement of the image of the target by refraction of light at the water surface. It has been suggested, and accepted, that Toxotes jaculatrix would avoid the effect of refraction by squirting vertically. In our previous study, however, Toxotes chatareus was observed to squirt under a wide range of angles, including angles much smaller than 90°. The aim of the present study was to asses in T. chatareus ( N=15), the frequency distribution of angles used, the relation between angle and probability to hit, the relation between target height and angle, and the smallest angles the fishes can use. The outcome was a distribution with a range of 102–58° and a median of 74°, no relation between angle and probability to hit, no relation between target height and angle and a smallest angle of 45°. The results clearly indicate that T. chatareus does not evade the refraction effect by squirting only vertically (90°), but masters a considerable refraction effect thanks to a mechanism that is not investigated here. The capacity to hit prey under a wide range of angles is seen as an important adaptation to the natural habitat where the visibility of prey is restricted by vegetation. The constraints of the range of angles are discussed.

Bearings-Only Target Motion Analysis Using a Dual-Waveband Infrared System

Infrared systems are widely used for target detection, designation and tracking. For example, an Infrared Search and Track (IRST) system, as a typical airborne or shipboard detecting device, is widely equipped for the remote target detection and tracking. In recent years, the problem of target motion analysis (TMA) and tracking has been studied increasingly extensively. In an airborne infrared system, the problem becomes more difficult due to absence of range information. In this paper, the infrared model and motion model of typical aerial targets are described. An airborne dual-waveband IRST system, which is quite familiar nowadays, is choosed for implementation of target motion analysis. Based on the above, a novel and more practical algorithm of target tracking via bearings-only measurements is formed and the major parameters are defined according to a typical airborne dual-waveband IRST system. Finally, data simulation is implemented, and the results demonstrate the new algorithm has a better performance than before for bearings-only target tracking.

Prey Catching in the Archer Fish: Marksmanship, and Endurance of Squirting At an Aerial Target

Archer fishes (Toxotidae) can bring down aerial arthropods with a yet of water from their mouth. Although most authors seem to assume that squirting down prey is the archer fish's source of food, it has been suggested that this typical foraging technique can not play an important role because, among other things, the height at which a prey can be hit is limited, the fishes soon tire of squirting, and other kinds of food are eaten. Owing to lack of information or differences concerning methods, small numbers of subjects, and may be, differences between species, there is little agreement about the performance of the fish. In order to provide reliable data on marksmanship, endurance of squirting, and diet, the performance of Toxotes chatareus was observed during 25 weeks while the fishes (N = 16) got daily practice squirting at prey. The fishes readily took various kinds of food. Squirting was found to be effective in that the fishes, within 4,5 squirts and 41 seconds, reliably hit targets at a height up to eight times their body length. Contrary to earlier reports, the fishes were found to persist squirting at a fixed target eight times per minute during at least 10 min. The results concerning marksmanship, and endurance, indicate that, contrary to what has been suggested, squirting can be an important way of foraging in the natural habitat.

Praćenje manevrišućih ciljeva preključivanjem Kalmanovih filtera

The complete procedure of tracking maneuvering aerial targets using Kalman filters switching is given. The procedure includes the detection of a sudden change of the target acceleration, the detection of a zero acceleration and the precise filter initialisation. The whole procedure is checked using computer simulation and the tracking procedure parameters are determined. The procedure can be easily programmed.

Autonomous Unmanned Aircraft R&D with a High Performance Flying Laboratory

The Defence Research Establishment Suffield conducts R&D into aerial target technologies to support the Canadian Forces in meeting current and future technology requirements. At present, a high degree of emphasis is being placed on providing technologies that facilitate realistic, cost-effective target presentations. These activities have included the development of unmanned flying laboratories such as the High-speed Aeronautical Technologies Testbed. This maneuverable flight platform, capable of both autonomous and semi-autonomous flight, is currently being utilized in exploring a number of technologies associated with airborne intelligent autonomous vehicles including highly agile evasive maneuvering. the ability to take “intelligent” actions to counter defensive measures, and novel control system architectures

Research in a high-fidelity acceleration environment

A description is given of the lightweight cockpit installed in the human centrifuge at the Naval Air Development Center as an approach to creating an acceleration environment similar to tactical aircraft. Its purpose is to provide a testing environment for advanced acceleration protection systems. The centrifuge is capable of very high onset/high sustained accelerations. A pilot in the human centrifuge flies an aircraft simulation to maintain a target aircraft inside the gun pipper of a head-up display. The pilot is in complete control of the centrifuge through the simulation, and, if the target tracking is accomplished successfully, the centrifuge will produce an acceleration profile that matches the target aircraft. The display system is a high-resolution wide-field-of-view computer graphics system that is used to present a real-world gaming area, an aerial target aircraft, and a high-fidelity head-up display. The cockpit is also outfitted with a medium-fidelity head-down display used to aid the subject in locating the target, provide an interactive terminal for G-induced-loss-of-consciousness recovery, and function as a NAVAID device. >

The Snipe Aerial Target System

The need for a realistic aerial target for air defence weapon systems is universally accepted. In these days of ever escalating costs the use of a full size manned aircraft or highly sophisticated drone becomes increasingly less attractive. It is to provide a realistic, low cost and cost effective alternative that the Aero Electronics Ltd., target range has been developed.

One Aerial Target System for all Air-to-Air and Surface-to-Air Weapons Firing Practices

One Aerial Target System for all Air-to-Air and Surface-to-Air Weapons Firing Practices