Airborne Objects Research Articles

Relief displacement of airborne objects

ABSTRACT The increasing availability of unoccupied aircraft systems (UAS, also referred to as drones) has led to their use in taking vertical aerial photographs at relatively small spatial scales. These photographs can be used to measure the distances between objects appearing in the photographs. However, relief displacement can cause an object above or below ground level to appear at a point in a vertical aerial photograph that is not directly in-line with the object’s actual location, causing a measurement error. A UAS was used in this study as a photographed airborne object because its location and altitude could be controlled. We were interested in predicting the horizontal distance of the UAS’s appearance from the centre of a vertical aerial photograph. Predictions of the location of the photographed UAS’s appearance in vertical aerial photographs over both level and sloped surfaces matched measured appearance distances within 0.06–0.48 m. This study shows that the relief displacement formulas typically used to compute the height of a vertical structure appearing in a vertical aerial photograph can additionally be used to compute the actual location of an airborne object (e.g., a flying UAS, bird, bat) if the object’s altitude is known or can be estimated.

Small Airborne Object Recognition with Image Processing for Feature Extraction

Small Airborne Object Recognition with Image Processing for Feature Extraction

Unauthorized Drone Detection Using Deep Learning

Abstract: The growing concerns over drone misuse in national airspace, including activities like drug smuggling and privacy violations, demand advanced drone detection systems. Traditional methods struggle to accurately identify drones among various airborne objects. YOLO v8, renowned for its efficient single-pass object detection, presents a sophisticated solution. Through training on annotated datasets featuring drones in diverse environments and fine-tuning with aerial imagery, YOLO v8 excels at recognizing drones amidst complex backgrounds. Its multi-scale detection capabilities enable it to detect drones of varying sizes, crucial for different distances from the camera. Real-time prediction ensures timely detection, vital for immediate responses to unauthorized intrusions. Integration with drone tracking systems enhances situational awareness, facilitating proactive measures. Furthermore, employing adaptive thresholding and post-processing techniques like Kalman filtering refines drone detection accuracy, reducing false positives. YOLO v8 thus emerges as a potent tool in mitigating risks associated with drone misuse, bolstering defenses against unauthorized activities in national airspace.

Measuring the Elevation Angle of an Airborne Object by Phase Direction Finding in a Multi-Ring Antenna Array

Measuring the Elevation Angle of an Airborne Object by Phase Direction Finding in a Multi-Ring Antenna Array

An Efficient Adjacent Frame Fusion Mechanism for Airborne Visual Object Detection

With the continuous advancement of drone technology, drones are demonstrating a trend toward autonomy and clustering. The detection of airborne objects from the perspective of drones is critical for addressing threats posed by aerial targets and ensuring the safety of drones in the flight process. Despite the rapid advancements in general object detection technology in recent years, the task of object detection from the unique perspective of drones remains a formidable challenge. In order to tackle this issue, our research presents a novel and efficient mechanism for adjacent frame fusion to enhance the performance of visual object detection in airborne scenarios. The proposed mechanism primarily consists of two modules: a feature alignment fusion module and a background subtraction module. The feature alignment fusion module aims to fuse features from aligned adjacent frames and key frames based on their similarity weights. The background subtraction module is designed to compute the difference between the foreground features extracted from the key frame and the background features obtained from the adjacent frames. This process enables a more effective enhancement of the target features. Given that this method can significantly enhance performance without a substantial increase in parameters and computational complexity, by effectively leveraging the feature information from adjacent frames, we refer to it as an efficient adjacent frame fusion mechanism. Experiments conducted on two challenging datasets demonstrate that the proposed method achieves superior performance compared to existing algorithms.

Towards Efficient Detection and Tracking for Tiny Airborne Object

Towards Efficient Detection and Tracking for Tiny Airborne Object

Модель оценки вероятности обнаружения воздушных объектов обзорной радиолокационной станцией метрового диапазона с инверсным радиолокационным синтезированием апертуры

The article presents a model for estimating the probability of detecting airborne objects under the conditions of using a modern radar station with inverse aperture synthesis while providing the task of detecting and resolving such objects. The results of computer simulation are presented.

An airborne object detection and location system based on deep inference

In recent years, with the development of sensors, communication networks, and deep learning, drones have been widely used in the field of object detection, tracking, and positioning. However, there are inefficient task execution and some complex algorithms still need to rely on large servers, which is intolerable in rescue and traffic scheduling tasks. Designing fast algorithms that can run on the airborne computer can effectively solve the problem. In this paper, an object detection and location system for drones is proposed. We combine the improved object detection algorithm ST-YOLO based on YOLOX and Swin Transformer with the visual positioning algorithm and deploy it on the airborne end by using TensorRT to realize the detection and location of objects during the flight of the drone. Field experiments show that the established system and algorithm are effective.

Assessment of the quality of determining the coordinates of air objects by cooperative radar systems for air surveillance

In the presented work, based on the classification of airspace surveillance radar systems in the form: independent non-cooperative radar surveillance, independent cooperative radar surveillance, dependent cooperative radar surveillance; the quality of determining the coordinates of air objects by the systems under study was assessed. The place and role of these information systems in the information support of airspace control and air traffic control systems is shown. From the calculations carried out, we can draw the following conclusion that the sensitivity of measuring the height of an airborne object significantly depends on the geometry of the location of receiving points of a synchronous network of radar surveillance systems. As the distance between receiving points increases, the area covered by curves of equal sensitivity increases. It is substantiated that when using equal weight in the accuracy of range measurement and in measuring the altitude of an airborne object, the accuracy of the synchronization of the time scales of the receiving points is the value achieved by modern means of time synchronization. The use of the given methodology for assessing the quality of measuring the coordinates of air objects in a synchronous network of cooperative radar surveillance systems for airspace allows us to put forward requirements for the synchronism of time scales in a unified synchronous information network of radar surveillance systems when measuring the coordinates of air objects. It is shown that the price for improving the accuracy of determining the coordinates of air objects by a synchronous network of cooperative radar systems is the complication of the system due to an increase in positions, an increase in the number of transceiver paths, the need to synchronize emission processes, receive signals and control viewing modes.

Using Software-Defined radio receivers for determining the coordinates of low-visible aerial objects

The object of this study is the process of determining the coordinates of low-visible aerial objects. The main hypothesis of the research assumed that the signals emitted by airborne systems of airborne objects that are not visible to radar stations have a greater power than the signal reflected from the airborne object. This, in turn, could improve the signal/noise ratio and, accordingly, the accuracy of determining the coordinates of low-visible aerial objects. It is suggested to use Software-Defined Radio receivers to receive such signals emitted by on-board systems of low-visible aerial objects. It was established that the main sources of signals for Software-Defined Radio receivers are signals of command, telemetry, target channels, manual control channels, and satellite navigation. It was established that an additional distinguishing feature when determining the coordinates of low-visible aerial objects is the uniqueness of their spectra and spectrograms. The method of determining the coordinates of low-visible aerial objects when using Software-Defined Radio receivers has been improved, which, unlike the known ones, involves: – the use as signals for Software-Defined Radio of signal receivers of on-board equipment of low-visible aerial objects; – the use of a priori coordinate values of a low-visible aerial object; – conducting additional spectral analysis of signals of on-board systems of low-visible aerial objects. The spectra and spectrograms of signals of on-board systems of aerial objects when using non-directional and directional antennas were experimentally determined. The experimental studies confirm the possibility of using the Software-Defined Radio receiver to receive signals from airborne equipment and improve the signal-to-noise ratio. The accuracy of determining the coordinates of aerial objects when using Software-Defined Radio receivers was evaluated. A decrease in the error of determining plane coordinates by the Software-Defined Radio system of receivers compared to the accuracy of determining coordinates by the P-19 MA radar station was established by an average of 1.88–2.47 times, depending on the distance to the aerial object

Air safety information space - genesis and present day

AbstractIn the article, the author presents the genesis and development of the air safety information space from the moment when it was needed to create the NATO Integrated Air and Missile Defense System. It synthetically presents important facts contributing to its development, describes the methods of obtaining, collecting and analyzing, and above all, the use of infor-mation on airborne objects from the beginning of World War I to the present day, also empha-sizing its practical dimension in the non-military sphere. The author identifies the air safety information space as a virtual and physical space in which information about the situation in the air and space is received, processed and transmitted. Consisting of active participants, ne-tworks, data, information and information systems, creating a specific "information environ-ment" composed of the following systems: radar reconnaissance, radio-electronic reconnais-sance, aviation management, airspace management, air defense, telecommunications, remote sensing and many others. The author sees the primary source of information as the radar re-connaissance system that provides information about the air situation and the tools for mana-ging this information. Radiolocation information managed by personnel using automated harvesting systems and its development allows for the recognition, identification and tracking of airborne apparatuses moving in the airspace. The technical and human potential of radiolo-cation reconnaissance possessed and used on a daily basis allows for a thesis that it is the basis of airspace reconnaissance and constitutes a very solid foundation in building situational awa-reness in this space. An area where assessments are made and task decisions of key importance to air safety are made.Keywords: information space, air safety, information environment, air defense, information, air object.

Comparative analysis of the quality of detection of air objects by secondary radar systems

The work is devoted to a comparative analysis of the quality of detection of air objects by secondary radar systems. The purpose of the work is a comparative analysis of the optimal and quasi-optimal structure for detecting air objects by secondary interrogation radar systems. A significant role in the information support of the airspace control and air traffic control system is played by secondary radar systems for airspace surveillance, which include secondary radars and identification problems on the basis of “friend or foe” identification. Note that in existing networks of radar surveillance systems, tracking of airborne objects is usually carried out using information from primary radar surveillance systems, and secondary radar surveillance systems are used as sources of additional radar information. In this regard, the problems of assessing the quality of detection of air objects by secondary radar systems, the specifics of the construction and operation of which differ significantly from the primary airspace surveillance radar systems, are relevant. Thus, increasing the probabilistic characteristics of the system of secondary radar systems when an aircraft transponder operates in the field of significant flows of intentional and intra-system interference is ensured by choosing detection thresholds depending on the values of the transponder readiness coefficient and the probability of suppression of individual response signal pulses. On the other hand, the use of detection thresholds on secondary radar systems that are optimal for the given operating conditions of the transponder makes it possible to reduce the requirements for the throughput of the aircraft transponder with a significant intensity of flows of intra-system and intentional correlated interference. Analysis of the characteristics of detection of air objects by secondary radar systems shows that: optimal thresholds for detecting air objects in secondary radar systems significantly depend on the readiness factor of the aircraft transponder and the probability of suppression of individual pulses of response signals in the response channel; the use of decoding response signals and subsequent accumulation when choosing the optimal threshold significantly reduces the detection quality indicators compared to optimal processing of a burst of response signals; the digital threshold for detecting air objects in a secondary radar system largely depends on the probability of signal suppression in the request channel and response channel.

Detection range of airborne objects by broadband active-passive radar systems

In the interests of searching and observing aerial objects with low levels of background contrast of secondary electromagnetic radiation and signals of on-board radio-electronic means, it is required to use active-passive radar systems with identification of the belonging of unmasking signs identified by heterogeneous information sensors to one object. When constructing procedures for joint processing of information signals, the issues of determining the range of active and passive search (observation) channels become important when implementing measures to reduce the reflective properties and structural and energy secrecy of the operation of electronic equipment of aircraft. To establish the boundaries of the area controlled by the active-passive radar system, it is necessary to use energy equations for transmitting and receiving broadband signals with a priori indefinite arrival time in a radio channel with scattering and a direct radio channel. The equations are found by integrating spectral equations for inharmonic wave processes propagating in free space in the band of cyclic operating frequencies when approximating the partial directional coefficients of antennas and partial effective scattering areas of objects by power functions of cyclic frequencies. The goal of the article is identification of patterns of influence of object reflective properties and characteristics of airborne radio sources on the range of active-passive radar systems. Using energy equations of transmission-reception of non-harmonic wave processes in a radio channel with scattering and direct radio channel, analytical expressions for determining probabilistic characteristics of signal detection with a priori indefinite arrival time, the possibilities of detecting air objects by broadband active-passive radar systems have been investigated. Ratios of ranges of detection of objects have been found based on the results of receiving and processing of information signals of radar stations and intrinsic radiation of airborne radio-electronic equipment. The revealed regularities of the influence of the object reflective properties and the characteristics of airborne radio sources on the range of radar stations and passive radar complexes allow us to make a rational choice of parameters of active-passive radar system designs in order to achieve the required indicators of the effectiveness of air space control. The energy equations of transmission and reception of broadband signals in radio channels form the basis for the development of proposals to ensure the covert use of aircraft.

Optimization of the Risk Functional to Control the Composition and Structure of a Heterogenous Grouping of Detection Sensors in Three-Dimensional Space

The steady growth in the scale and dynamics of the use of aerial weapons in the course of various conflicts necessitates the formulation and solution of the problems of building realistic systems to detect them. It should be noted that the priorities in the development of detection sensors is changing from solving problems to improve their characteristics to optimization and adaptability in controlling them. As an object, a heterogeneous grouping of sensors, which solves the problem of detecting a moving airborne object, is considered. The subject is the methodology for constructing control models for heterogeneous detection sensors. Based on the analysis of the antagonistic interaction of a heterogeneous grouping and airborne objects, as well as the processes of their functioning, a geometric approach to solve the problem of detecting a moving object (MO) is proposed, which uses an adapted and improved risk functional as one of the possible indicators for the further synthesis of the control algorithms. The practical effectiveness of the application of this functionality is substantiated and compared with other performance indicators through simulation modeling.

Distributed processing of radar information in airspace surveillance systems

The work is dedicated to the analysis of the quality of combining assessments of the radar signals and airborne objects detections in the implementation of distributed processing of radar information of airspace surveillance systems. The main sources of radar information about the air situation in the airspace control system are primary surveillance radars, secondary radar systems and identification systems on the basis of "friend or foe". It should be noted that the analysis of the information security of single-position radars shows their vulnerability in a wide range of unintentional and intentional interference, as well as determining their location. This is due to the ease of detection of the emitting transmitter of the probing signal in single-position radars. It led to the main disadvantage of single-position radars – low noise immunity and low survivability. The transition to a network of radar systems can significantly reduce the impact of deliberately directed interference. It also allows the use of methods for distributed processing of radar information in airspace surveillance systems.
 Analysis of the effectiveness of information support algorithms based on distributed processing of radar information of airspace surveillance systems, taking into account the final result, makes it possible to detect airborne objects using a packet of binary-quantized signals, taking into account two algorithms for combining detection results: channel accumulation and combining results; association of channel solutions and accumulation. It shows following: – the quality of consumer information support based on the proposed structure is much higher compared to the used radar information processing structure; the quality of information support for consumers has the best performance when using the signal processing method based on the accumulation of signals with the subsequent combination of detection results; the availability factor of the aircraft transponder significantly affects the quality of information support, already at P0<0.9 the use of integer logic for combining detection information is undesirable.

The Methods for Improving the Quality of Detection of Inconspicuous Aerial Objects Through the Use of External Radiation Sources

The article focuses on the methods for improving the quality of detection of inconspicuous aerial objects through the use of external radiation sources. It has been established that the existing methods for improving the quality of detection of airborne objects do not meet modern requirements for detection indicators. The energy potential of modern radars is limited. Therefore, the article proposes detection methods that combine active radar and nontraditional principles for detecting airborne objects. In the article, we will focus only on two main methods for improving the quality of detection of small airborne objects. This is the use of energy from digital television receivers (external radiation source) and the use of information from ADS-B receivers. Technically, this means introducing an additional receiving channel into the radar. The gain in the conditional probability of correct detection for bistatic signal reception (compared to monostatic) is due to the properties of the bistatic effective scattering surface. It is shown that with the additional use of digital television signals, the quality of detection of airborne objects is improved. It is shown that the additional use of information from the ADS-B receivers makes it possible to increase the accuracy of determining the coordinates of an air object up to 40-50%, depending on the parameters of the movement of an air object. The subject of advanced research is the development of methods for suppressing the penetrating signal when using digital television and the development of methods for detecting airborne objects not equipped with the ADS B system. Keywords— aerial object, detection, quality, third-party source, ADS-B, digital TV, radar

A Hardware and Software Platform for Aerial Object Localization

To date, there are little reliable data on the position, velocity and acceleration characteristics of Unidentified Aerial Phenomena (UAP). The dual hardware and software system described in this document provides a means to address this gap. We describe a weatherized multi-camera system which can capture images in the visible, infrared and near infrared wavelengths. We then describe the software we will use to calibrate the cameras and to robustly localize objects-of-interest in three dimensions. We show how object localizations captured over time will be used to compute the velocity and acceleration of airborne objects.

Trapping of Airborne Objects by Using Camera Tracking in Acoustic Levitation

Trapping of Airborne Objects by Using Camera Tracking in Acoustic Levitation

Uniformity Correction of CMOS Image Sensor Modules for Machine Vision Cameras.

Flat-field correction (FFC) is commonly used in image signal processing (ISP) to improve the uniformity of image sensor pixels. Image sensor nonuniformity and lens system characteristics have been known to be temperature-dependent. Some machine vision applications, such as visual odometry and single-pixel airborne object tracking, are extremely sensitive to pixel-to-pixel sensitivity variations. Numerous cameras, especially in the fields of infrared imaging and staring cameras, use multiple calibration images to correct for nonuniformities. This paper characterizes the temperature and analog gain dependence of the dark signal nonuniformity (DSNU) and photoresponse nonuniformity (PRNU) of two contemporary global shutter CMOS image sensors for machine vision applications. An optimized hardware architecture is proposed to compensate for nonuniformities, with optional parametric lens shading correction (LSC). Three different performance configurations are outlined for different application areas, costs, and power requirements. For most commercial applications, the correction of LSC suffices. For both DSNU and PRNU, compensation with one or multiple calibration images, captured at different gain and temperature settings are considered. For more demanding applications, the effectiveness, external memory bandwidth, power consumption, implementation, and calibration complexity, as well as the camera manufacturability of different nonuniformity correction approaches were compared.

DEVELOPMENT OF A VIDEO PROCESSING MODULE FOR THE TASK OF AIR OBJECT RECOGNITION BASED ON THEIR CONTOURS

The subject of research in the article is the module of automatic segmentation and subtraction of the background, which is created, based on the sequential application of methods of image preprocessing and modified method of interactive segmentation of images and implemented in the system of optical monitoring of the air situation. The aim of the work is to develop an image segmentation module to increase the efficiency of recognition of an air object type on a video image in the system of visual monitoring of the air environment by means of qualitative automatic segmentation. To solve this problem, a modified interactive algorithm in the mode of automatic selection of an object in the image, which allows more accurately, without the participation of the operator, to determine the foreground pixels of the image for further recognition of the type of airborne object. The following tasks are solved in the article: the analysis of existing methods of binarization of color images for semantic segmentation of images, which are used in image recognition systems; the development of a pipeline of methods for automatic segmentation of images in the system of optical monitoring of the air environment. In the work, the following methods are used: methods of digital image processing, methods of filtering and semantic segmentation of images, methods of graph analysis. The following results are obtained: the results of image processing with the proposed module of segmentation and background subtraction confirm the performance of the module procedures. The developed pipeline of methods included in the module demonstrates correct segmentation in 93% of test images in automatic mode without operator participation, which allows us to conclude about the effectiveness of the proposed module. Conclusions: The implementation of the developed module of segmentation and background subtraction for the system of optical monitoring of the air environment allowed to solve the problem of segmentation of video images for further recognition of aerial objects in the system of optical monitoring of the air environment in automatic mode with a high degree of reliability, thus increasing the operational efficiency of this system.