Primary Radar Research Articles

ACCURACY ANALYSIS OF AIRCRAFT POSITION PARAMETERS PROVIDED BY GCA 2000 AIRPORT SURVEILLANCE RADAR

The aim of this article was to investigate the accuracy of determining the position parameters of an aircraft by the GCA 2000 airport control radar located at Deblin Airport (EPDE). In order to analyse the accuracy of determining the position of an aircraft by the GCA 2000 radar, a research flight was carried out. The position of the aircraft was recorded by the GCA 2000 radar and the Thales Mobile Mapper Pro GPS receiver on board the aircraft. The resulting position parameters were compared with each other to investigate the accuracy of the radar’s coordinate determination. In addition, a number of analyses and comparisons were performed to determine the reasons for the interruptions in the radar detection of the aircraft. Based on the study, it can be concluded that the GCA 2000 radar located at Deblin airport meets the requirements set by the International Civil Aviation Organisation (ICAO) for radar performance. According to ICAO, the standard deviation of the distance error should be 70–130 metres and the azimuth error for primary radars should be 0.15–0.2°, and for secondary radars 0.2–0.3°. The standard deviation of the distance error during a research flight by the GCA 2000 radar is 81.1 metres and the standard deviation of the azimuth error is 0.19°.

Fusion of Identification Information from ESM Sensors and Radars Using Dezert–Smarandache Theory Rules

This paper presents a method of fusion of identification (attribute) information provided by two types of sensors: combined primary and secondary (IFF) surveillance radars and ESMs (electronic support measures). In the first section, the basic taxonomy of attribute identification is adopted in accordance with the standards of STANAG 1241 ed. 5 and STANAG 1241 ed. 6 (draft). These standards provide the following basic values of the attribute identifications: FRIEND; HOSTILE; NEUTRAL; UNKNOWN; and additional values, namely ASSUMED FRIEND and SUSPECT. The basis of theoretical considerations is Dezert–Smarandache theory (DSmT) of inference. This paper presents and uses in practice six information-fusion rules proposed by DSmT, i.e., the proportional conflict redistribution rules (PCR1, PCR2, PCR3, PCR4, PCR5, and PCR6), for combining identification information from different ESM sensors and radars. This paper demonstrates the rules of determining attribute information by an ESM sensor equipped with the database of radar emitters. It is proposed that each signal vector sent by the ESM sensor contains an extension specifying a randomized identification declaration (hypothesis)—a basic belief assignment (BBA). This paper also presents a model for determining the basic belief assignment for a combined primary and secondary radar. Results of the PCR rules of sensor information combining for different scenarios of a radio electronic situation (deterministic and Monte Carlo) are presented in the final part of this paper. They confirm the legitimacy of the use of Dezert–Smarandache theory in information fusion for primary radars, secondary radars, and ESM sensors.

АЛГОРИТМ ТРАЕКТОРНОЙ ОБРАБОТКИ ДЛЯ АВТОМАТИЧЕСКОГО ОТСЛЕЖИВАНИЯ РАСПРЕДЕЛЕННЫХ ДВИЖУЩИХСЯ ЦЕЛЕЙ В УСЛОВИЯХ МНОГОЛУЧЕВОГО РАССЕЯНИЯ

This work presents a modified Poisson multi-Bernoulli mixture (PMBM) algorithm, adapted to perform trajectory processing tasks under conditions of multipath radar reflection. Based on the evaluative data of the previous kinematic state, size, and orientation of the target obtained using the extended PMBM algorithm, a pre-processing stage is carried out. During this stage, the origins of primary radar detections are initially classified. Then, after classification, these radar detections are further processed to estimate the state of targets at the next point in time. To assess the effectiveness of the proposed algorithm, a simulation modeling method based on MATLAB is used. With its help, scenarios for tracking distributed targets are modeled under conditions of the emergence of false signals from multipath radar reflections. The simulation results endorse the algorithm's capability to concurrently track multiple targets upon receiving primary radar detections from an assortment of radars amidst multipath radar reflections. The application of the algorithm finds use in the field of autonomous driving, driver assistance systems, applications ensuring driver safety, and other areas.

A Novel Approach Towards Rain Test on an Airborne Aesa

Centre for Airborne Systems (CABS) has designed, developed and successfully qualified Active Array Antenna Unit (AAAU) - a state-of-art technology system for airborne applications and mounted on Indigenous Airborne Early Warning and Control (AEW & C) aircraft. AAAU houses Active Electronically Steered Antenna (AESA) of Primary and Secondary Radar and front end electronics of the radar. These electronics positioned inside AAAU use ram air cooling. To comply with the all-weather conditions, an important test is the Rain test in which the radar effectiveness is verified. This paper presents a novel, cost effective and tailor made methodology adopted to suit the requirements for qualification of the AAAU. On successful completion of the test, AAAU is certified by Centre for Military Airworthiness and Certification (CEMILAC) authorities for flying under rainy conditions and has been accepted by the Indian Air Force.

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.

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.

К ВОПРОСУ ПРИМЕНЕНИЯ ЗАКОНА АБЕРРАЦИИ В РАДИОНАВИГАЦИИ И АВИАЦИОННОМ НАБЛЮДЕНИИ

The author analyzes the potential use of the aberration law which describes the deviation of measured parameters of an observed object as it changes its position relative to the observer. The law was studied in terms of its application in radio navigation and aircraft surveillance. During research the author obtained dependences of deviations of observable and real (true) characteristics of an observed object for such aids of radio-technical support of flights as a primary radar, distance measuring equipment (DME) and a ground station of automatic dependent surveillance. In doing so, the speed of the observed object was set equal to 250 m/s (typical for existing airplanes) and 600 m/s (specific for perspective supersonic airplanes). It follows from the calculations that the aberration effect cannot be detected for determining slant range or pulse duration tasks due to the imperfection of the existing measuring instruments. However, the aberration effect can be detected in the tasks of determining the time interval between probing pulses of the primary radar or automatic dependent surveillance messages, as well as in the determination of the frequency of the DME signal. This is achieved due to a sufficiently large dynamic range of the measured values. For the method of evaluating the aberration effect given in the paper the author performed estimation of the sensitivity to the errors of the measured value and the velocity of the observed object. The research confirmed possibility to apply the law of aberration in practice for radio navigation aids and aircraft surveillance, which can increase accuracy of position-fixing and determination of aircraft movement parameters as well as to expand capabilities of the available equipment.

Improving the safety of provided ATS at LZTT by implementing MLAT

Nowadays the air traffic services are provided with surveillance and procedural services are not used any more. In order to provide radar services at airports we need to have 100% coverage. The combination of present technologies gives us the opportunity to provide such services even at mountainous terrains. The paper deals with air traffic services and their improvements at Poprad-Tatry international airport. In the first part it shows characteristics of primary radar and problems associated with its operation as the radar is out-dated. In the second part the authors describe secondary radar and problems with too high minimum vectoring altitudes and an inappropriate location of SSR ground station. In the last part a new technology – MLAT is presented and other benefits such as improved coverage, lower electrical consumption, redundancy etc. The paper shows risks associated with implementations of such a technology and a safety risk tolerability matrix is created.

Joint antenna selection and waveform design for coexistence of MIMO radar and communications

As the problem of spectral congestion is becoming severe, the coexistence between two primary spectrum users, radar and communications, has spurred extensive research interest. To reduce the mutual interferences between the two functions, MIMO radar waveform design needs to consider the compatibility in both spectral and spatial domains, where the former is achieved by null forming in the frequency domain and the latter is achieved by shaped beampattern synthesis. Additionally, high power efficiency and low system overhead are two desirable characteristics for MIMO radar system design. To this end, we first introduce a new realistic waveform constraint, peak-to-valley-power-ratio (PVPR) constraint per antenna to improve the power efficiency. Then, combined with PVPR constraint, we propose a switchable individual antenna power control scheme to jointly optimize waveforms and antenna locations. We adopt a max–min beampattern matching criterion and impose the ell _{2,1}-norm penalty on the waveform matrix to promote the sparsity of the array. To solve the resultant non-smooth and non-convex problem, we develop a modified alternating directions method of multipliers, where a surrogate subproblem over primal variables is solved instead of the original problem, and its local convergence is analyzed. Finally, numerical experiments demonstrate the effectiveness and superiority of the proposed method over counterparts, especially obtaining the lowest sidelobe level and deeper spectral nulls using much fewer antennas.

Enhancing the performance of the Primary Surveillance Radar using Multilateration

One way to improve the measurements of the PSR (Primary Surveillance Radar) is to utilize the cinematic model of the aircraft (A/C) in a Kalman filter. Another newly developed method would be to implement multilateration using a large number of ground-based ADS-B (Automatic Dependent Surveillance-Broadcast) receivers. Originating in airport surveillance, multilateration grew to become the primary system for ATM (Air Traffic Management) in airspaces without PSR coverage. Given that each of the systems has its own advantages and limitations, we propose an evaluation of an alternative approach that uses data from multiple ADS-B receivers to implement a data fusion algorithm between PSR acquired position and MLAT (Multilateration) estimated position. Among the many ways to implement data fusion, have chosen to analyze two possible solutions: the direct fusion of the two available positions provided by the two systems using a traditional Kalman Filter and a linearization approach for the multilateration solution that does not require position computation. In both cases, these will improve the Kalman filter and lower the position estimation errors. The evaluation takes into consideration the possible sources of inaccuracies and provides sensibility analyses in regards to the number and positioning of ADS-B receivers involved in multilateration. This paper will conclude with a discussion of the computational power required for the two implementations.

Interactive air situation simulator

In the present day, simulators play a significant role in training military personnel. They allow, among other things, for practicing combat scenarios that are difficult or outright impossible to execute in reality. Virtual reality technologies are being constantly developed, as are the ways of their interaction with each other and with real objects. This article brings up the topic of interactive distributed simulations, presenting their technological developments as well as the goals of their authors. After the analysis of selected methods of interactive distributed simulations, project assumptions are formulated and interactions occurring between objects in virtual airspace are stated. The last part of the article describes the attempt of creating an interactive air situation simulator in accordance with the formulated assumptions. As a result of the work conducted, it was possible to program a simulator that allows us to study the interactions between radar warning receivers and ground based primary surveillance radars. Not all assumptions have been achieved, most notably full functionality with the DIS standard, however, the project can be further developed, allowing for full compatibility with this standard. Developing a simulator is a process that requires many assumptions, but also trade-offs. With correct assumptions and a standardised way of information exchange between simulators, it is possible to make a web of interoperable simulators. Keywords: aerospace engineering, simulators, radars, distributed interactive simulation

Impact of Structures on the Operation of Air Traffic Radiolocation and Radionavigation Surveillance Systems

The article describes interference affecting the operation of radiolocation and radionavigation devices used in the air traffic surveillance systems, caused by the proximity of building structures. The impact of a hypothetical structure on the operation of primary and secondary air traffic surveillance radars and DVOR/DME beacons was simulated. The results of this simulation are presented in the form of airspace sectors in which false identification of aircraft may occur, and where it will not be possible to identify aircraft or use beacons due to the certain portion of airspace being in the shadow created by the structure. Analysis of the possibility of the PSR radar receiver being blocked by a strong signal reflected from a nearby building was performed as well.

Improving the Reliability of the Information and Measurement System of Aviation Surveillance

It is shown that various sensors are used to ensure air traffic control in civil aviation, namely: primary and secondary radars, multilateration surveillance systems, automatic dependent surveillance systems of broadcast and contract types, multistatic radars. Based on the analysis of the main disadvantages of the considered systems, it was concluded that the use of multilateration aircraft surveillance systems (MLAT) is promising. The need to improve the reliability of MLAT is noted. The work proposes a method of structural and informational redundancy of MLAT based on the introduction of an additional receiver into its design. It allows to measure the distance to the aircraft using the energy method. The analysis of increasing the reliability of MLAT at various redundancy rates is carried out.

Joint Radar-Communications Exploiting Optimized OFDM Waveforms

We propose novel Joint Radar-communication spectrum sharing strategies exploiting orthogonal frequency-division multiplexing (OFDM) waveforms that concurrently achieve the objectives of both radar and communication systems. An OFDM transmitter is considered that transmits dual-purpose OFDM subcarriers such that all the subcarriers are exploited for the primary radar function and further exclusively allocated to the secondary communication function serving multiple users. The waveform optimization is performed by employing mutual information (MI) as the optimization criterion for both radar and communication operations. For the purpose of radar performance optimization, we consider the MI between the frequency-dependent target response and the transmit OFDM waveforms. On the other hand, communication system performance is evaluated in terms of the MI between the frequency-dependent communication channels of communication users with the transmit OFDM subcarriers. These optimization objectives not only enable the transmit power allocation of the OFDM subcarriers, but also govern the subcarrier distribution among the communication users. Two resource optimization scenarios are considered, resulting in radar-centric and cooperative resource allocation strategies that exploit convex and mixed-integer linear programming optimization problems for power allocation and subcarrier distribution, respectively. We further present a chunk subcarrier allocation approach that applies to both optimization strategies to reduce the computational complexity with a trivial performance loss. Simulation results are presented to illustrate the effectiveness of the proposed strategies.

Reversible Jump MCMC for Deghosting in MSPSR Systems.

This paper deals with bistatic track association and deghosting in the classical frequency modulation (FM)-based multi-static primary surveillance radar (MSPSR). The main contribution of this paper is a novel algorithm for bistatic track association and deghosting. The proposed algorithm is based on a hierarchical model which uses the Indian buffet process (IBP) as the prior probability distribution for the association matrix. The inference of the association matrix is then performed using the classical reversible jump Markov chain Monte Carlo (RJMCMC) algorithm with the usage of a custom set of the moves proposed by the sampler. A detailed description of the moves together with the underlying theory and the whole model is provided. Using the simulated data, the algorithm is compared with the two alternative ones and the results show the significantly better performance of the proposed algorithm in such a simulated setup. The simulated data are also used for the analysis of the properties of Markov chains produced by the sampler, such as the convergence or the posterior distribution. At the end of the paper, further research on the proposed method is outlined.

ASSESSMENT OF THE QUALITY OF INFORMATION SUPPORT BY AIR RADAR SURVEILLANCE SYSTEMS

The paper pays attention to the consideration of the structure of user's information support of the airspace control system at the stage of primary information processing by the joined radar system. This system includes a primary and identification surveillance system, which allows considering the overall structure as a single synchronous network of surveillance information systems. Such a structure can be characterized by an overall integrated quality indicator of the information support of the airspace control system. Such a quality indicator can be the probability of information support, which is the product of the probabilities of correct detection of an air object by the primary radar and identification system on the basis of "friend-foe" and the probability of comparing the coordinate information of primary radar systems and identification systems. This approach allows changing the model of combining information for primary radar systems and identification systems so as to take into account the estimated coordinates of the air object by both information systems due to the weight combination of coordinates of air objects. The calculation of the coordinates of air objects according to the information of the primary radar systems and identification systems allows improving the quality of information support for decision makers in the air traffic control system.

Microstrip Antenna Design with Patch Rectanguler for Primary Surveillance Radar (PSR) L-Band Application

This research aims to design an inexpensive primary surveillance radar (PSR) antenna with high efficiency and works on the L-Band frequency by using a microstrip antenna, this antenna has advantages in terms of ease of design, light weight and low production prices. The design of the antenna design is made in a simulation that works at a frequency of 1.3 GHz, the substrate material is made of Fr-4 which has a dielectric constant value (er) of 4.3, while the patch material is made of copper. The antenna has a patch size of 71 x 54 mm array 2x1, while the size of the ground plane is 222 x 124.8 mm. Antenna performance testing is done by looking at S-Parameter simulation and voltage standing wave ratio (VSWR). To get an accurate value at a frequency of 1.3 GHz, the sweep method is applied to the patch by changing the width and length of the patch. From the simulation results we get the S-Parameter value right at the frequency of 1.3 GHz with a return loss value of -35 dB while the value of VSWR of 1.29 indicates the antenna has a high efficiency. This research aims to create an antenna innovation that is based on inexpensive and has high efficiency.

The Overview of Human Localization and Vital Sign Signal Measurement Using Handheld IR-UWB Through-Wall Radar.

Obtaining information (e.g., position, respiration, and heartbeat rates) on humans located behind opaque and non-metallic obstacles (e.g., walls and wood) has prompted the development of non-invasive remote sensing technologies. Due to its excellent features like high penetration ability, short blind area, fine-range resolution, high environment adoption capabilities, low cost and power consumption, and simple hardware design, impulse radio ultra-wideband (IR-UWB) through-wall radar has become the mainstream primary application radar used for the non-invasive remote sensing. IR-UWB through-wall radar has been developed for nearly 40 years, and various hardware compositions, deployment methods, and signal processing algorithms have been introduced by many scholars. The purpose of these proposed approaches is to obtain human information more accurately and quickly. In this paper, we focus on IR-UWB through-wall radar and introduce the key advances in system design and deployment, human detection theory, and signal processing algorithms, such as human vital sign signal measurement methods and moving human localization. Meanwhile, we discuss the engineering pre-processing methods of IR-UWB through-wall radar. The lasts research progress in the field is also presented. Based on this progress, the conclusions and the development directions of the IR-UWB through-wall radar in the future are also preliminarily forecasted.

Multi-Object Detection and Tracking, Based on DNN, for Autonomous Vehicles: A Review

Multi-object detection and multi-object-tracking in diverse driving situations is the main challenge in autonomous vehicles. Vehicle manufacturers and research organizations are addressing this problem, with multiple sensors such as camera, LiDAR, RADAR, ultrasonic-sensors, GPS, and Vehicle-to-Everything-technology. Deep Neural Networks (DNN) are playing a predominant role to solve this. Fusing the sensing modalities with DNN will be the leading solution to this challenge. This paper evaluates the state-of-the-art techniques that address this challenge, with three primary sensors camera, LiDAR, and RADAR with DNN, and fusion of sensor data with DNN. The analysis shows that there exists an excellent potential to design a more optimized solution to address this challenge. This work proposes a perception model for autonomous vehicles.

Fully Differential Ultra-Wideband Amplifier With 46 −dB Gain and Positive Feedback for Increased Bandwidth

This brief reports a three-stage fully differential UWB amplifier with high and flat gain. It is proposed to be applied in the receiver part of a primary IR-UWB radar that is designed for real-time pedestrian localization. The amplifier was fabricated using 45 nm SOI CMOS technology and has been measured on a probe station and was demonstrated on a PCB. A differential cascode structure with positive feedback is employed and offers 45.8±0.5 dB gain (S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sub> ) with a -3 dB bandwidth from 3.1 GHz to 10.6 GHz. The amplifier also achieves a wideband and flat input impedance matching with return loss smaller than -10 dB. The measured minimum noise figure is about 4 dB. The output power at 1 dB compression point is 10.2 dBm at 7 GHz. The amplifier occupies an active chip area of 0.4 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and consumes 125 mW from a 1.5 V supply. To the best knowledge of the authors, the proposed amplifier provides the highest gain and the best FOM in this frequency band in comparison with other designs that have been reported to date.