Search

The indigenous C-band tracking radar is a 4D radar providing Monopulse track data in range, azimuth, elevation and Doppler. It is a land based Transportable system meant for Target Tracking from any designate site. It consists of a Retractable Dual axis pedestal integrated to a platform structure. The radar has been designed and developed based on state of the art digital technologies, which include FPGA based Digital Receiver, Digital Control, Synthetic Radar Display and FPGA based timing signal generation. This paper describes design and development features that result in high tracking accuracy at large dynamics.

The role of the en route air traffic control specialist (ATCS) is vital to maintaining safety and efficiency within the National Airspace System (NAS). ATCSs must vigilantly scan the airspace under their control and adjacent airspaces using an En Route Automation Modernization (ERAM) radar display. The intent of this research is to provide an understanding of the expert controller visual search and aircraft conflict mitigation strategies that could be used as scaffolding methods during ATCS training. Interviews and experiments were conducted to elicit visual scanning and conflict mitigation strategies from the retired controllers who were employed as air traffic control instructors. The interview results were characterized and classified using various heuristics. In particular, representative visual scanpaths were identified, which accord with the interview results of the visual search strategies. The highlights of our findings include: (1) participants used systematic search patterns, such as circular, spiral, linear or quadrant-based, to extract operation-relevant information, (2) participants applied an information hierarchy when aircraft information was cognitively processed (altitude -&gt, direction -&gt, speed), (3) altitude or direction changes were generally preferred over speed changes when imminent potential conflicts were mitigated. Potential applications exist in the implementation of the findings into the training curriculum of candidates.

This paper’s contributions are design principles and graphical components for air traffic control officer radar displays. The graphics inform of flights passing into uncontrolled airspace and contr...

Digital Radio Frequency Memory (DRFM) is the core of any electronic jamming system. It is a high-speed sampling digital memory in which the radar signal itself is stored, modulated with jamming signals and then retransmitted to the threat. The signal transmitted back by the DRFM-based jammer is a simple replica of the original signal with some parameters manipulated. The DRFM capability is essential for jamming pulsed doppler radars. One of the open research problems in DRFM jammer design is the relative motion between radar, DRFM jammer and platform (an aircraft), and its effects on jammer's performance. It has been investigated that in case of relative motion between DRFM jammer and targeted radar, pulse width (PW) and pulse repetition interval (PRI) variation i.e., shrinkage or expansion will be observed depending upon direction of motion. This variation in PW and PRI is proportional to relative velocity, acceleration and jamming time of the DRFM jammer. In this paper, the effects of radial motion on a moving DRFM jammer are presented, and an efficient strategy is proposed to tackle them in the stand-in jamming (SIJ) scenario. MATLAB simulations and Verilog implementation of the proposed strategy is carried out to certify the analytical model. PW and PRI variation are employed as the principal performance metrics to quantify the proposed approach, by leveraging timing diagram analysis and PPI radar display.

With the increasing traffic volume, air traffic controllers (ATCos) highly efficient performance plays an essential part in ensuring the safety and managing within limited manpower and resources. To ensure the performance, one way is to perform situation awareness (SA) examination. However, the known SA methods (such as text query) are either subjective or inapplicable in a practical scenario. Therefore, the use of physiological signals is becoming popular. In this work, a real time monitoring approach is proposed to assess a general monitoring awareness while looking at the events happening at the radar display during air traffic control (ATC), using neurophysiological measures taken from electroencephalogram (EEG) signals along with eye-tracking metrics such as eye fixation count and duration. Seven university engineering students participated in the attentive and non-attentive radar monitoring activities. The preliminary experimental results revealed that the real-time data of EEG, average fixation count, and fixation duration highlight distinct differences in levels between attentive and non-attentive monitoring activities (individual and collective). Also, the cognitive resource required for air traffic management (ATM) monitoring is relatively high. Such measures can be used as complementary data sets to gauge and validate an ATCos general SA Civil Aviation Authority of Singapore (CAAS) Accepted version This project is supported by the Civil Aviation Authority of Singapore and Nanyang Technological University, Singapore under their collaboration in the Air Traffic Management Research Institute. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not reflect the views of the Civil Aviation Authority of Singapore. The authors would also like to thank all the participants for their valuable time.

Two experiments were conducted to examine whether the disruptive effects of extraneous speech observed in the laboratory can be found with aviation-related tasks. The first experiment examined whether background speech can disrupt performance on an auditory/verbal task, which required participants to recall navigation information. The second experiment examined whether background speech can disrupt performance on a visuo/spatial task, which required participants to recall a target’s track history on a radar display. The results indicated that the presence of background speech disrupts performance on both these tasks, despite participants trying to ignore it. The results are interpreted in the light of the theories pertaining to the ‘irrelevant sound effect’.

To better understand people's interpretations of National Weather Service's tornado warning polygons, 145 participants were shown 22 hypothetical scenarios in one of four displays—deterministic polygon, deterministic polygon + radar image, gradient polygon, and gradient polygon + radar image. Participants judged each polygon's numerical strike probability (ps) and reported the likelihood of taking seven different response actions. The deterministic polygon display produced ps that were highest at the polygon's centroid and declined in all directions from there. The deterministic polygon + radar display, the gradient polygon display, and the gradient polygon + radar display produced ps that were high at the polygon's centroid and also at its edge nearest the tornadic storm cell. Overall, ps values were negatively related to resuming normal activities, but positively correlated with expectations of resuming normal activities, seeking information from social sources, seeking shelter, and evacuating by car. These results replicate the finding that participants make more appropriate ps judgments when polygons are presented in their natural context of radar images than when the polygons are presented in isolation and that gradient displays appear to provide no appreciable benefit. The fact that ps judgments had moderately positive correlations with both sheltering (a generally appropriate response) and evacuation (a generally inappropriate response) provides experimental confirmation that people threatened by actual tornadoes are conflicted about which protective action to take.

Weather radar is now widely viewed by the general public in the United States via television, computers/tablets, and smartphones. Anyone can consult near-real-time maps and animations of weather radar data when weather conditions are a factor. However, the usefulness of weather radar data for each user depends on a complex interaction of factors. There have been few studies providing conceptual arguments and empirical data to better understand what the most important factors are and to comprehend patterns of public weather radar use across the United States. The first part of this research provides a basic conceptual framework for research investigating the usefulness of weather radar displays as a source of weather information and as a decision aid. The second part aims to uncover several factors that influence the perceived usefulness rating of the National Weather Service (NWS) website’s weather radar display at both national and regional levels using variables gathered from the 2014 NWS customer satisfaction survey alongside relevant geographic and climatological variables. Data analyses include spatial clustering and ordinal regression utilized within a generalized linear model methodology. Overall, respondents who are more familiar with the NWS and their products, as well as those who indicate they are more likely to take action based on information provided by the NWS, are more likely to find the NWS radar display useful. Geographically, the NWS radar display is most useful to persons residing in the southern United States. Lightning is the most important hazard associated with higher radar usefulness ratings.

An eye-tracking experiment was conducted to examine whether differences in forecasters’ eye movements provide further insight into how radar update speed impacts their warning decision process. In doing so, this study also demonstrates the applications of a new research method for observing how National Weather Service forecasters distribute their attention across a radar display and warning interface. In addition to observing forecasters’ eye movements during this experiment, video data and retrospective recalls were collected. These qualitative data were used to provide an explanation for differences observed in forecasters’ eye movements. Eye movement differences were analyzed with respect to fixation measures (i.e., count and duration) and scanpath dimensions (i.e., vector, direction, length, position, and duration). These analyses were completed for four stages of the warning decision process: the first 5 min of the case, 2 min prior to warning decisions, the warning issuance process, and warning updates. While radar update speed did not impact forecasters’ fixation measures during these four stages, comparisons of scanpath dimensions revealed differences in their eye movements. Video footage and retrospective recall data illustrated how forecasters’ interactions with the radar display and warning interface, encounters with technological challenges, and varying approaches to similar tasks resulted in statistically significantly (p value < 0.05) lower scanpath similarity scores. The findings of this study support the combined use of eye-tracking and qualitative research methods for detecting and understanding individual differences in forecasters’ eye movements. Future applications of these methods in operational meteorology research have potential to aid usability studies and improve human–computer interactions for forecasters.

[EN] Multiple-input multiple-output (MIMO) radars have been shown to improve target detection for surveillance applications thanks to their proven high-performance properties. In this paper, the design, implementation, and results of a complete 3-D imaging frequency-modulated continuous-wave MIMO radar demonstrator are presented. The radar sensor working frequency range spans between 16 and 17 GHz, and the proposed solution is based on a 24-transmitter and 24-receiver MIMO radar architecture, implemented by timedivision multiplexing of the transmit signals. A modular approach based on conventional low-cost printed circuit boards is used for the transmit and receive systems. Using digital beamforming algorithms and radar processing techniques on the received signals, a high-resolution 3-D sensing of the range, azimuth, and elevation can be calculated. With the current antenna configuration, an angular resolution of 2.9° can be reached. Furthermore, by taking advantage of the 1-GHz bandwidth of the system, a range resolution of 0.5 m is achieved. The radio-frequency front-end, digital system and radar signal processing units are here presented. The medium-range surveillance potential and the high-resolution capabilities of the MIMO radar are proved with results in the form of radar images captured from the field measurements.

Safety-critical systems like air traffic control (ATC) are usually less automated than might be expected by the public, so human intelligence will remain at the core in the decision-making (DM) process. Meanwhile, human factors (HFs) need to be fully considered in the DM process, which can design the ATC system to be more intelligent and more adaptive to the behaviour of the user. However, the existing DM research lacks the systematic methods that fully consider human performance in a smart manner. This study proposed a human-centred adaptive DM methodology that combines subjective and objective measurements made by functional near-infrared spectroscopy (fNIRS) via intelligent automation (IA). Moreover, this paper also described a case study of radar display map operation, including descriptive and optimised maps, to illustrate the proposed approach and verify its feasibility and effectiveness. The results were determined by jointly considering the user-generated and system-generated data and suggested that the proposed approach could capture subjective and objective data, take into consideration the HFs information to provide real-time online feedback and adjust the decision support system to HFs. It is hoped that this study can promote the methodology of human-centred subjective and objective data-driven applications in the future ATC environment adaptive decision research.

Ionospheric sounding is a technique that provides real-time data on high-frequency ionospheric-dependent radio propagation. This letter presents a Universal Software Radio Peripheral-based ionospheric sounding radar, which relies on a basic system consisting of a synchronized transmitter and receiver. The radar has the advantages of miniaturization, modularization, low power, and low cost. The three most significant features of the radar system are that it is software-defined and universal platform-based and that it has low transmitting power. This novel software-defined vertical-incidence radar system can probe the ionosphere and obtain real-time plasma parameters according to the simulation. Ionograms that directly express probe results are generated by MATLAB after data processing and simulation. Successful development of such an ionospheric sounding software radar will allow universalization and miniaturization of an ionosonde radar system. This letter introduces the implementation of the novel ionospheric sounding radar.

A stepped-frequency radar that allows for adaptability in the radiated spectrum while maintaining high-resolution radar imagery has been developed. The spectrally agile frequency-incrementing reconfigurable (SAFIRE) radar system is a vehicle-mounted, ground-penetrating radar that is capable of producing high-resolution radar imagery for the detection of obscured targets (either buried or concealed surface targets). It can be easily transitioned between forward- and side-looking orientations. The SAFIRE system is capable of precisely excising subbands within its operating bandwidth, thus making the system “spectrally agile.” It is also highly reconfigurable thereby allowing for on-the-fly adjustment of many of the system parameters. The spectrally agile and reconfigurable aspects of the SAFIRE radar together with its enhanced IF processing scheme represent a novel contribution to the state of the art. This paper discusses the system design, implementation, and performance characteristics, and also presents preliminary high-resolution imagery.

Frequency-modulated continuous wave radar systems suffer from permanent leakage of the transmit signal into the receive path. Besides leakage within the radar device itself, an unwanted object placed in front of the antennas causes so-called short-range (SR) leakage. In an automotive application, for instance, it originates from signal reflections of the car’s own bumper. Particularly the residual phase noise of the downconverted SR leakage signal causes a severe degradation of the achievable sensitivity. In an earlier work, we proposed an SR leakage cancellation concept that is feasible for integration in a monolithic microwave integrated circuit. In this brief, we present a hardware prototype that holistically proves our concept with discrete components. The fundamental theory and properties of the concept are proven with measurements. Further, we propose a digital design for real-time operation of the cancellation algorithm on a field programmable gate array. Ultimately, by employing measurements with a bumper mounted in front of the antennas, we show that the leakage canceller significantly improves the sensitivity of the radar.

When a pulse radar signal is implemented in a range-limited anechoic chamber for radar measurement, the transmitted and reflected signal will be coupled at the receiver. To solve this problem and equivalently simulate the whole process of pulse radar measurement in an anechoic chamber, the interrupted transmitting and receiving method is proposed in this letter based on interrupted sampling. The constraints of the transmitting and receiving parameters are deduced with the sizes of the anechoic chamber and target. The pulse compression of the proposed method is performed. Then, the window function is applied to extract the main peaks after pulse compression. Both the simulation and experimental results are provided to demonstrate the effectiveness of the proposed method in overcoming the coupling between the transmitted and reflected pulse signals.

When Privates George Elliott and Jo s eph Lockard discovered a large fleet of airplanes approaching Pearl Harbor, Hawai'i, on the morning of 7 December 1941, they were operating a new U.S. Army Signal Corps radar that used the same antenna for transmitting and receiving RF energy [1]. RF engineers had to quickly develop a variety of new techniques to keep the multikilowatt transmitter signals from degrading or damaging the sensitive receivers in those early systems. This past December marked the 75th anniversary of that event. Tying in with the exhibit of related hardware at the IEEE Microwave Theory and Techniques Society's (MTT-S) 2017 International Microwave Symposium in Honolulu this June, the goal of this article is to highlight some of the components and circuits used for transmit?receive (T/R) switching in U.S. radars from the pre-World War II era through the following few decades.

Regulators, aware of the significant underutilization of spectrum reserved for radar operation, are starting to open these bands for sharing with commercial services. In this paper, we provide the signal processing techniques necessary to apply temporal sharing to reduce radar exclusion zones and increase spectral efficiency. Our approach directly extends to the fairly common scenario of multiple radars operating at relatively close distance in the same frequency and allows a secondary user to transmit without exceeding a stipulated level of interference at any radar. We require only that radars behave periodically; our secondary users apply adaptive sensing to track radar behavior in real-time without a priori information. To accomplish this, we introduce a pulse deinterleaving mechanism to separate multiple radar emissions in real-time, with no batch or offline processing. We show that our approach to temporal sharing is applicable to static or low mobility sharing scenarios, where the interference channel displays quasi-periodic features.

This paper reviews recent progress of portable short-range noncontact microwave radar systems for motion detection, positioning, and imaging applications. With the continuous advancements of modern semiconductor technologies and embedded computing, many functionalities that could only be achieved by bulky radar systems in the past are now integrated into portable devices with integrated circuit chips and printed circuits boards. These portable solutions are able to provide high motion detection sensitivity, excellent signal-to-noise ratio, and satisfactory range detection capability. Assisted by on-board signal processing algorithms, they can play important roles in various areas, such as health and elderly care, veterinary monitoring, human-computer interaction, structural monitoring, indoor tracking, and wind engineering. This paper reviews some system architectures and practical implementations for typical wireless sensing applications. It also discusses potential future developments for the next-generation portable smart radar systems.

Noise radars possess several advantageous properties, including low probability of detection and identification, especially when working in continuous-wave mode. One of the main drawbacks of such radars is the occurrence of the masking effect, when a weak target echo is masked by the sidelobes of a strong target echo. The sidelobes of the ambiguity function emerge on the level of the time–bandwidth product below the main peak and are spread in the entire range–Doppler plane. While most approaches to mitigate the masking effect focus on the processing of the received signal, it is possible to move the computation burden to the waveform design phase. This paper describes a filter-based method of creating noise-like waveforms that have very low sidelobes in the area of certain range and Doppler shifts. Both theoretical analysis and measurement results are presented and compared with the lattice filter method of masking effect cancellation.

An original 3-D radar imaging system is presented for radar cross section (RCS) analysis, i.e., to identify and characterize the radar backscattering components of an object. Based on a 3-D spherical experimental setup, where the residual echo signal is more efficiently reduced in the useful zone, it is especially adapted to deal with low-RCS analysis. Due to a roll rotation, the electric field direction varies concentrically while the scattered data are collected. To overcome this issue, a specific 3-D radar imaging algorithm is developed. Based on fast regularization inversion, more precisely the minimum norm least squares solution, it manages to determine, from a single pass collection, three huge 3-D scatterer maps at once, which correspond to HH, VV, and HV polarizations at emission and reception. The algorithm is applied successfully to real X-band datasets collected in the accurate 3-D spherical experimental layout, from a metallic cone with patches and an arrow shape. It is compared with the conventional 3-D polar format algorithm where the scatterer information is irretrievably mixed-up.

Most applications of frequency-modulated continuous-wave radar described in the literature involve targets that are in relatively close proximity to the radar. In these cases, the round-trip travel time of the target’s radar signature is small relative to the transmit chirp duration, simplifying the processing required for range and velocity extraction. This is not the case for more distant targets, where much of the radar signature is received after the start of the subsequent transmit waveform. In this letter, we examine various signal-processing options for coping with this long-range condition. We analytically demonstrate how to retain both range and Doppler shift information for an arbitrary number of targets spaced anywhere from very near the target up to the radar’s unambiguous range. The motivation for this work is to develop a 95-GHz Doppler radar for measuring ice and dust particle dynamics in cometary jets. Simulations and experimental results are provided to validate our methods.

Automotive radars, along with other sensors such as lidar, (which stands for "light detection and ranging"), ultrasound, and cameras, form the backbone of self-driving cars and advanced driver assistant systems (ADASs). These technological advancements are enabled by extremely complex systems with a long signal processing path from radars/sensors to the controller. Automotive radar systems are responsible for the detection of objects and obstacles, their position, and speed relative to the vehicle. The development of signal processing techniques along with progress in the millimeter-wave (mm-wave) semiconductor technology plays a key role in automotive radar systems. Various signal processing techniques have been developed to provide better resolution and estimation performance in all measurement dimensions: range, azimuth-elevation angles, and velocity of the targets surrounding the vehicles. This article summarizes various aspects of automotive radar signal processing techniques, including waveform design, possible radar architectures, estimation algorithms, implementation complexity-resolution trade off, and adaptive processing for complex environments, as well as unique problems associated with automotive radars such as pedestrian detection. We believe that this review article will combine the several contributions scattered in the literature to serve as a primary starting point to new researchers and to give a bird's-eye view to the existing research community.

TARA (Telescope Array Radar) is a cosmic ray radar detection experiment colocated with Telescope Array, the conventional surface scintillation detector (SD) and fluorescence telescope detector (FD) near Delta, Utah, U.S.A. The TARA detector combines a 40 kW, 54.1 MHz VHF transmitter and high-gain transmitting antenna which broadcasts the radar carrier over the SD array and within the FD field of view, towards a 250 MS/s DAQ receiver. TARA has been collecting data since 2013 with the primary goal of observing the radar signatures of extensive air showers (EAS). Simulations indicate that echoes are expected to be short in duration (~10 microseconds) and exhibit rapidly changing frequency, with rates on the order of 1 MHz/microsecond. The EAS radar cross-section (RCS) is currently unknown although it is the subject of over 70 years of speculation. A novel signal search technique is described in which the expected radar echo of a particular air shower is used as a matched filter template and compared to waveforms obtained by triggering the radar DAQ using the Telescope Array fluorescence detector. No evidence for the scattering of radio frequency radiation by EAS is obtained to date. We report the first quantitative RCS upper limits using EAS that triggered the Telescope Array Fluorescence Detector., Comment: 21 pages, 30 figures

Based on the resonance absorption effect of plasma, the mechanism of plasma jamming technology is studied and verified in this letter. Different from the power perspective, the effects of plasma on the radar echo waveform and the radar signal detection are studied. It is found that the radar echo waveform is distorted and the performance of pulse compression is degraded. Moreover, the phenomenon of radar false targets appears with several meters apart. Thus, plasma could not only act as electromagnetic wave absorbers, but also a kind of passive jammer. Finally, many optimal plasma parameters are presented to achieve desired jamming effects for different radar frequencies. These data provide some useful references to plasma jamming technology.

The aim of the radar systems is to collect information about their surroundings. In many scenarios besides static targets there are numerous moving objects with very different characteristics, such as extent, movement behavior or micro-Doppler spread. It would be most desirable to have algorithms that extract all information on static and moving object automatically, without a system operator. In this paper, we present measurements conducted with a commercially available high-resolution multi-channel linear frequency-modulated continuous-wave radar and algorithms that do not only produce radar images but a description of the scenario on a higher level. After conventional spectrum estimation and thresholding, we present a clustering stage that combines individual detections and generates representations of each target individually. This stage is followed by a Kalman filter based multi-target tracking block. The tracker allows us to follow each target and collect its properties over time. With this method of jointly estimating tracks and characteristics of each individual target in a scenario, inputs for classifiers can be generated. Which, in turn, will be able to generate information that could be used for driver assistance or alarm trigger systems.

Multiple-input-multiple-output (MIMO) radar image processing presents problems difficult to address by modifying conventional monostatic radar methods as Fourier range migration. When the distance between the transmitter and receiver is comparable to the target size, the single phase center approximation is not accurate. Furthermore, if the antenna radiation pattern significantly deviates from a spherical wave, the symmetries assumed in most range migration techniques are violated. We present a rapid Fourier-based MIMO reconstruction called Fourier accelerated multistatic imaging (FAMI) suitable for massively parallel computation that accounts for frequency-dependent radiation patterns, does not require the single phase center approximation, and is able to dynamically adapt to different target support volume shapes. FAMI is especially suitable for frequency-diversity antenna systems that use spectrally modulated coded spatial radiation patterns.

This paper presents an innovative radar architecture to improve the isolation of the harmonic radar between the transmitter and the receiver. The proposed radar transmits two closely located frequencies to the transponder, and the transponder transmits a response signal at a mixed frequency. Because the frequency of the response signal is different from those of the clutter and leakage signals, the isolation is significantly improved. For a traditional harmonic radar, the leakage signals should be suppressed to a sensitivity lower than −106 dBm to avoid interference. The proposed radar requires only attenuation of leakage signals to a level lower than −8 dBm to avoid low-noise amplifier saturation. Harmonic radar transponders are compatible with the proposed radar system without additional design. This paper also proposes a new method for maintaining the correlation of transmitter and receiver phase noise. Field test results demonstrate that leakage signal interference in the proposed radar is far lower than that in the harmonic radar. The significant improvement in isolation reveals the advantages of applying the frequency mixing concept in the proposed radar.

Adverse weather conditions can have major impacts on air traffic and its control (ATC) in terms of safety and capacity. However, today's ATC situation data displays hardly contain any weather information. Controllers only manually react on external forecasts or status reports to re-plan the aircraft flight paths. The project “Meteorology for Air Traffic Management” (MET4ATM) uses nowcast and forecast weather data for aircraft re-routing calculations and visualization of weather in the radar display. If our Arrival Manager (AMAN) detects that a planned four-dimensional aircraft trajectory is affected by severe weather, it will consider the respective weather polygon, severity, moving direction, and extension for an aircraft re-routing via a detour point. However, the weather situational awareness of the controller would still not be given without further information on the radar display. Therefore, we describe advanced visualization techniques, i.e. a morphing algorithm, to let nowcast polygons become forecast polygons over time until the next weather data update appears. Our implemented prototype highlights weather and re-route affected aircraft, presents smoothly moving weather polygons on the radar display, and gives concrete 4D-trajectory based advisories for re-routing taking the complete arrival stream into account. This continuous support will help controllers to optimize high dynamic air traffic flow even if aircraft do not completely follow the automatically generated plan. In this way the whole severe weather approach operations remain supported by the controller assistance systems and therefore within standard processes.

A complete circularly polarized 210–270-GHz frequency-modulated continuous-wave radar with a monostatic homodyne architecture is presented. It consists of a highly integrated radio-frequency transceiver module, an in-house developed linear-frequency chirp generator, and a data acquisition chain. The radar front end featuring a fundamentally operated $\times$ 16 multiplier-chain architecture is realized as a single chip in 0.13- $\mu$ m SiGe heterojunction bipolar transistor technology with a lens-coupled circularly polarized on-chip antenna and wire-bonded on a low-cost printed circuit board. In combination with a 9-mm-diameter silicon lens, the module achieves an average in-band directivity of 26.6 dB. The measured peak radiated power from the packaged radar module is $+$ 5 dBm and the noise figure is 21 dB. For a 60-GHz frequency sweep, the radar achieves a range resolution of 2.57 mm after calibration, which is close to the theoretical bandwidth-limited resolution of 2.5 mm. With a simple scanning optical setup, this paper further demonstrates the 3-D imaging capability of the radar for detection of hidden objects with a remarkable dynamic range of around 50 dB.

This paper presents the design of a compact Radar for real-time detection of targets in smart mobility applications. The Radar integrates Fabry-Perot resonating antennas, X-band and configurable continuous wave transceiver, high-speed analog-digital-converter and low-power/low-cost FPGA for the baseband signal processing. The latter includes region-of-interest selection, 2D Fast Fourier Transform for range-Doppler map extraction, peak detection and alarm decision logic. The transmitted power can be configured from few mW to 1.8W. This allows for a trade-off between the maximum detection range, from few hundreds of meters up to 1.54km, and the Radar power consumption, from 2.56W to 11.66W. The measured speed is up to 40m/s. The speed and distance resolutions are 0.3m/s and 37.5cm, respectively. The configurable Radar features increased robustness vs. laser-scanners, video cameras, or induction loops detection techniques, and stands for its better trade-off in terms of covered range, size, and low-power consumption vs. state-of-the-art surveillance Radars. Design of a compact Radar module for real-time detection of targets in smart mobility applications.Real-time implementation of Radar signal processing tasks on low-cost and low-power FPGA, reducing power dissipation vs. state-of-the-art designs using GPU (Graphical Processing Units) and GPP (General Purpose Processors).Radar parametric analysis highlighting the inter-dependencies existing among Radar performance and analog and digital circuit parameters. This allows a co-design of the mixed-signal Radar transceiver with the FPGA-based digital signal processing, and a trade-off between the Radar performance and its implementation complexity.Coarse-grained and a fine-grained configurability of the Radar transmitted power, which allows for different trade-offs between the system power consumption and the maximum covered range.

A survey of radar systems used in the medical field is presented. First, medical applications of radars are described, and some emerging research fields are highlighted. Then, medical radars are analyzed in terms of block diagrams and behavioral equations and some implementations are shown as examples. A section is dedicated to the radiating structures used in these radars. Finally, human safety and environmental impact issues are addressed. The most investigated medical applications of radars are breast tumor diagnostics and remote monitoring of cardiorespiratory activity. New fields of interest are physiological liquid detection, and the monitoring of artery walls and vocal cord movements. Among the various topologies, continuous wave (CW) radars have been proven to yield the highest range resolution that is limited only by the system noise while the resolution of ultra wideband (UWB) and frequency modulated continuous wave (FMCW) radars is also related to the used frequency bandwidth. Concerning the maximum range, UWB radars have the best performance due to their ability to operate in the presence of environmental clutter. As for the radiating structures, planar antennas are preferred for diagnostic applications, due to their small dimensions and good matching when placed in contact with the human body. Radar systems for remote monitoring, instead, are designed by using high gain antennas and taking into account the complex radar cross section (RCS) of the body.

Foreign object debris (FOD) on airport runways must be removed immediately. To detect small debris, we proposed and developed an optically-connected distributed-type 96 GHz millimeter-wave radar system based on radio-over-fiber (RoF) technology and an optical fiber network. The proposed distributed-type radar system offers both improved FOD detection characteristics and cost performance. This paper details the design and field feasibility evaluation of the 96 GHz frequency-modulated continuous wave radar system that uses RoF and an optical frequency multiplier. Firstly, the problem of long distance RoF transmission, which limits the practical use of the RoF networked radar system in the airport environment, is discussed. Secondly, the concept and architecture of the millimeter-wave radar system are discussed and demonstrated focusing on its use in actual airports. Then, the results of a field experiment are shown to confirm the feasibility of the radar system. Finally, the effectiveness of the high-speed signal processing and generation circuits inside the central unit is evaluated at an actual airport based on the results of non-coherent and coherent signal integration.

The fundamental task of a radar is target detection, that is, determining whether or not a target exists. Over time, however, expectations have grown regarding the information that radar can obtain. Today, besides target detection, many parameters can be estimated-such as velocity and position-about many kinds of targets, and targets can also be classified with modern radar units. Technological developments in electronic systems and signal processors mean that returned signals from a target can be analyzed with a high degree of precision, so the returned signal is more valuable today when compared to the early days of radar systems.

We present a physical layer solution to RF distance bounding, which reduces the prover’s processing delay virtually to zero by employing the concepts of frequency modulated continuous wave (FMCW) and secondary radars, and equipping it with the capability of cryptographic communication over unintelligent radar signals . To realize, we encode the verifier’s challenges in waveform slope of signals while the prover communicates its cryptographic replies in shape of backscatter modulation. For resilience to multipath, the prover introduces analog frequency modulation using the principle of secondary radar. Our protocol is based on pre-commitment distance bounding scheme. Our paper primarily focuses on design intricacies of a realizable system while we briefly present the simulation results. We critically analyze the security of our protocol against attacks most concerned in distance bounding and thoroughly investigate its robustness under noise and multipath environments. A shortcoming of our design is low range resolution at lower spectral bandwidths, which can be foretoken as system tolerance. We foresee our endeavor to present a viable zero-delay RF distance bounding scheme while minimizing the hardware, energy, and computational overhead for passive and semipassive tokens.

In this paper, an $S$ -band radar system that uses stretch processing is developed at the chip level. The novelty in this paper lies in providing an integrated, compact and miniaturized high-performance $S$ -band radar system chipset. The radar has many characteristics that ensure high performance: 1) a wide bandwidth signal (600 MHz) that provides high resolution to distinguish between close objects; 2) an usage of stretch processing, which dramatically reduces the required sampling rates and relaxes the specifications of analog-to-digital converters; 3) high dynamic range (58 dB) that allows weak signals to be detected from targets masked by the high levels of clutter (such as snow and rain); 4) multiple receiver channels that enable digital antenna beamforming at the receiver to mitigate any strong interferer; and 5) operation in the $S$ -band (2–4 GHz) that provides high immunity against clutter in long-range surveillance applications. The architecture study revealed a super-hetrodyne modulator and receiver architecture offered the best solution. The high-order filters were pushed off-chip to reduce silicon area, reduce power consumption, and improve filtering results. The circuit-level design focused on designing the receiver blocks. The design included a high linearity quad passive mixer, IF cascode and common source amplifiers, and a negative-gm voltage controlled oscillator. The total receiver system of the radar chipset was designed and simulated at the circuit level on IBM 180-nm CMOS technology. To the best knowledge of the authors, this is the first integrated and smallest high-performance $S$ -band radar to be designed.

This paper investigates the scenario in which a weak desired signal reaches a poorly selective receiver along with a high-powered pulsed radar occupying a neighboring channel. Traditionally, an automatic gain control (AGC) is used to fit the high-powered radar into the dynamic range of the receiver. However, this approach desensitizes the receiver because it also sacrifices the signal-to-noise ratio (SNR) of the desired signal. We propose the use of an auxiliary receive path to address this problem of strong neighboring channel signals. In this method, receiver gain is not lowered to avoid clipping. Instead, the strong signal is allowed to clip and distort the desired signal. This paper shows that only a subset of the symbols contained in the desired signal will be distorted; hence, redundancy within the desired signal (due to forward error correction) can be exploited to “fill the gaps” created by the distortion. The auxiliary path samples the envelope of the strong neighboring-channel signal and informs the decoder about which symbols are distorted (or “bad”) and which symbols are not distorted (or “good”). This additional information is shown to improve the estimation performance of the decoder in the presence of high-powered neighboring-channel radar. Using simulation and hardware-based experiments, it is shown that auxiliary-path-based receivers can obtain a significantly better throughput performance than AGC-based receivers.

Surveillance radars, i.e., radars for air-traffic control, air defense, missile tracking, and weather observation, have undergone major advancements over their approximately 80-year history. This development has resulted in five fundamental system architectures that differ mainly in their antenna configuration: the rotating reflector antenna, the rotating passive electronically steered antenna (PESA), the stationary PESA, the rotating active electronically steered antenna (AESA), and the stationary AESA. The development of these architectures may be viewed as an evolutionary progression, with each representing a distinct stage of evolution.

Surface-based radar system can be used for remote sensing of characteristics of sea arctic ice fields, such as speed and direction of ice motion, distance to an ice floe and thickness of ice. For this purpose, we offered multi-channel coherent interferometric radar system that operates on one wavelength (8 mm). The radar system is design to use pulse (with wide bandwidth) compression techniques, coherent integration, doppler and interferometric processing to obtain high loop sensitivity and high resolution on speed, range and altitude. Radar data are acquired line by line while rotating the transmitting and receiving antennas about a vertical axis. In this article the design, measurement principles, simulation results and characteristics of surface-based radar are presented.

In this letter, we report initial experimental results which provide the foundation for low-terahertz (low-THz) radar imagery for outdoor unstructured scenarios as expected in automotive sensing. The requirements and specifications for a low-THz single imaging radar sensor are briefly outlined. The imaging capabilities of frequency-modulated continuous-wave (FMCW) radar operating at 150 GHz are discussed. A comparison of experimental images of on-road and off- road scenarios made by a 150-GHz FMCW radar and a reference 30-GHz stepped-frequency radar is implemented, and their performance is analyzed.

To change the transmit beam pattern, single antenna radar requires a change of antenna while multiple antenna array radar, such as phased-array, require amplitude/phase tapers, which are hardware components. Therefore, there is a genuine demand that the parameters of future radar systems be controlled through a software without changing any hardware or using amplitude/phase tapers. It is well known that the parameters of an antenna array radar can be controlled by transmitting suitable correlated waveforms. This approach provides more degree-of-freedom and if constant-envelope (CE) or low peak-to-average power ratio (PAPR) correlated waveforms are used, it allows us to control the parameters of the radar without changing any hardware. Therefore, this approach can be considered as a step towards a software radar. The aim of this article is to provide a survey of recent techniques used to design CE and low PAPR correlated waveforms and discuss the benefits and drawbacks of each.

Using an experimental coherent high-resolution X-band radar, we show that micro-Doppler signatures from one or more walking persons can be retrieved off the radar line of sight in a realistic urban environment. The off-sightline objects are illuminated by the radar wave multipath wall reflections. Velocity–time diagrams are created for specific walking targets using the short-time Fourier transform. Two scenarios are studied, with one and two persons, respectively, walking along a closed path.

The introduction of photonics in microwave systems is setting new paradigms in radar architectures, providing new features potentially improving the surveillance effectiveness. In particular, photonics is enabling a new generation of the multiband radars able to manage multiple coherent radar signals at different frequencies simultaneously, with high and frequency-independent quality, enabling multispectral imaging for advanced surveillance systems. In fact, thanks to its high stability and huge bandwidth, photonics matches the urgent requirements of the performance and flexibility of the next-generation software-defined radar architectures, and it guarantees system compactness, thanks to the use of a single shared transceiver for multiband operations and to the potentials for photonic integration, which also promises reduced power consumption. In this paper, we present the first field trial, in a maritime scenario, of a fully coherent multiband radar enabled by the use of photonics. The paper reviews the basic concepts exploited for the photonic generation and the detection of the radar signals, and describes the extension to the multiband operation. We present details on the implementation and testing of a dual-band coherent radar system, discussing the potentials for a software-defined radio approach. Moreover, the results obtained after a simple digital data fusion are discussed, highlighting the capability of the coherent photonics-based multiband radars in exploiting the extended observation bandwidth for improving the system detection resolution with minimum computational costs.

Frequency modulated continuous wave (FMCW) radar is widely adopted solution for low-cost, short to medium range sensing applications. However, a multistatic FMCW architecture suitable for meeting the low-cost requirement has yet to be developed. This paper introduces a new FMCW radar architecture that implements a novel technique of synchronizing nodes in a multistatic system, known as over-the-air deramping (OTAD). The architecture uses a dual-frequency design to simultaneously broadcast an FMCW waveform on a lower frequency channel directly to a receiver as a reference synchronization signal, and a higher frequency channel to illuminate the measurement scene. The target echo is deramped in hardware with the synchronization signal. OTAD allows for low-cost multistatic systems with fine range-resolution, and low peak power and sampling rate requirements. Furthermore, the approach avoids problems with direct signal interference. OTAD is shown to be a compelling solution for low-cost multistatic radar systems through the experimental measurements using a newly developed OTAD radar system.

Microwave remote sensing instruments detect and image physical phenomena such as brightness temperature and volume reflectivity. The spatial resolution of these measurements is limited by the physical properties of the instrument such as the antenna size, the spatial scan pattern, and temporal sampling. Analysis shows that common sampling schemes undersample the spatial information present at the antenna. Here, we address methods to better capture the spatial information available by applying the Nyquist–Shannon sampling theory to the spatial averaging and sampling of remote sensing data. The use of overlapping windows for spatial averaging rather than treating pixels independently improves the image fidelity while maintaining the system sensitivity. Additionally, the sensitivity to spatially small targets can be maximized by matching the window shape to the antenna pattern. The spatial imaging of scanning radiometers, radars, and phased-array systems is addressed. These principles are demonstrated with the theory and data from the National Aeronautics and Space Administration Goddard Space Flight Center's High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP) radar.