Multi-mode Radar Research Articles

Incorporation of Digital Modulation into Vital Sign Detection and Gesture Recognition Using Multimode Radar Systems.

The incorporation of digital modulation into radar systems poses various challenges in the field of radar design, but it also offers a potential solution to the shrinking availability of low-noise operating environments as the number of radar applications increases. Additionally, digital systems have reached a point where available components and technology can support higher speeds than ever before. These advancements present new avenues for radar design, in which digitally controlled phase-modulated continuous wave (PMCW) radar systems can look to support multiple collocated radar systems with low radar-radar interference. This paper proposes a reconfigurable PMCW radar for use in vital sign detection and gesture recognition while utilizing digital carrier modulation and compares the radar responses of various modulation schemes. Binary sequences are used to introduce phase modulation to the carrier wave by use of a field programable gate array (FPGA), allowing for flexibility in the modulation speed and binary sequence. Experimental results from the radar demonstrate the differences between CW and PMCW modes when measuring the respiration rate of a human subject and in gesture detection.

SAR ADC for a Multimode Radar Transceiver with Offset Calibration

In this paper, we design a successive approximation register (SAR) analog-to-digital converter (ADC) suitable for multimode radar transceivers. For multimode radars, the sampling rate required by ADC varies according to the continuous wave (CW) or frequency modulated continuous wave (FMCW) used for operation. Therefore, depending on which waveform is used, the input is designed to enter two paths. For path 1, we obtained 9.23 bits of effective number of bits (ENOB), 57.35 dB of signal-to-noise distortion ratio (SNDR), and 64.62 dB of spurious free dynamic range (SFDR), and the power consumption was 0.3481 mW, resulting in a figure of merit (FOM) of 28.9 fJ/Conv-Step. On path 2, we obtained an 8.97 bit of ENOB, 55.76 dB of SNDR, and 60.53 dB of SFDR, and the power consumption was 1.72 μW, resulting in a FOM of 34.2 fJ/Conv-Step. Further, a circuit was constructed to reduce the offset of the comparator. As a result of 100 Monte Carlo simulations, the offset was reduced from -46 mV/+50 mV to -4 mV/+4 mV when the worst case was considered.

Moving target detection and tracking with multiplatform radar network (MRN)

A multiplatform radar network (MRN) composed of multiple transmitting and receiving facilities is advantageous over monostatic radar in moving target detection (MTD) and tracking due to the diversity gain. Within the framework of the Internet of Battlefield Things (IoBT), the authors propose that the airborne platforms equipped with the cognitive multimodal radar (CMR), the subarray-based MIMO radar (SMR), the active electronically scanned array (AESA) radar, and the adaptive radar countermeasures (ARC) should team up in target detection and tracking. To obtain better target detection and tracking performance, the probing signals from the CMR, the SMR, and the AESA radar are adaptively optimised based on the scenario under consideration. The ARC consists of two parts: 1) RF signal sensing and recognition with deep neural network (DNN), that is, to detect, identify, and localise multiple radio frequency emitters; 2) intelligent fake return creation and jamming to confuse the enemy radars in real time in the field. This work aims to serve as a good reference for future researchers interested in developing MRN with diverse nodes and the general teaming of radars on the battlefield.

RF Transceiver for the Multi-Mode Radar Applications.

In this work, a multi-mode radar transceiver supporting pulse, FMCW and CW modes was designed as an integrated circuit. The radars mainly detect the targets move by using the Doppler frequency which is significantly affected by flicker noise of the receiver from several Hz to several kHz. Due to this flicker noise, the long-range detection performance of the radars is greatly reduced, and the accuracy of range to the target and velocity is also deteriorated. Therefore, we propose a transmitter that suppresses LO leakage in consideration of long-range detection, target distance, velocity, and noise figure. We also propose a receiver structure that suppresses DC offset due to image signal and LO leakage. The design was conducted with TSMC 65 nm CMOS process, and the designed and fabricated circuit consumes a current of 265 mA at 1.2 V supply voltage. The proposed transmitter confirms the LO leakage suppression of 37 dB at 24 GHz. The proposed receiver improves the noise figure by about 20 dB at 100 Hz by applying a double conversion architecture and an image rejection, and it illustrates a DC rejection of 30 dB. Afterwards, the operation of the pulse, FMCW, and CW modes of the designed radar in integrated circuit was confirmed through experiment using a test PCB.

System Parameter Design of Multimodal Small Satellite SARs Operating in Scan Mode and Transmit Power Optimization for Marine Scenes

Multimodal small satellite synthetic aperture radar (SAR) is a new radar system under development that integrates an SAR, altimeter, scatterometer, and spectrometer. When applied to marine scenes, this system can be used to measure both marine targets and marine dynamic environments with high precision. This study addresses system parameter design for multimodal small satellite SAR operating in scan mode, and this design provides system parameters such as antenna size, signal bandwidth, pulse repetition frequency, scanning wavenumber and wave position for system simulation in scan mode. A method for optimizing the transmit power when illuminating a marine scene based on the wind speed and wind direction above the sea surface is studied. The goal is to fully use the characteristics of strong sea surface microwave scattering under a suitable wind speed and wind direction to reduce the required transmit power, thus improving the available data sampling time per orbit of a multimodal radar when working in SAR mode. Various simulation experiments were conducted, and the system parameter design results are given under scan mode. Furthermore, imaging simulation results of ocean scenes are also given under conventional and decreased power after optimization. The results show that good ocean scene imaging results are obtained when the designed system parameters are used for system simulation. In addition, the simulation results also verify that when the sea surface wind speed is relatively high and the wind direction is suitable, an acceptable ocean scene imaging result can still be obtained by using reduced transmit power.

Design of Multi-Mode Radar Signal Processor for UAV Detection

Design of Multi-Mode Radar Signal Processor for UAV Detection

Signal classification method based on data mining for multi-mode radar

For the multi-mode radar working in the modern electronic battlefield, different working states of one single radar are prone to being classified as multiple emitters when adopting traditional classification methods to process intercepted signals, which has a negative effect on signal classification. A classification method based on spatial data mining is presented to address the above challenge. Inspired by the idea of spatial data mining, the classification method applies nuclear field to depicting the distribution information of pulse samples in feature space, and digs out the hidden cluster information by analyzing distribution characteristics. In addition, a membership-degree criterion to quantify the correlation among all classes is established, which ensures classification accuracy of signal samples. Numerical experiments show that the presented method can effectively prevent different working states of multi-mode emitter from being classified as several emitters, and achieve higher classification accuracy.

Deterministic Bayesian information fusion and the analysis of its performance

This paper develops a mathematical and computational framework for analyzing the expected performance of Bayesian data fusion, or joint statistical inference, within a sensor network. We use variational techniques to obtain the posterior expectation as the optimal fusion rule under a deterministic constraint and a quadratic cost, and study the smoothness and other properties of its classification performance. For a certain class of fusion problems, we prove that this fusion rule is also optimal in a much wider sense and satisfies strong asymptotic convergence results. We show how these results apply to a variety of examples with Gaussian, exponential and other statistics, and discuss computational methods for determining the fusion system's performance in more general, large-scale problems. These results are motivated by studying the performance of fusing multi-modal radar and acoustic sensors for detecting explosive substances, but have broad applicability to other Bayesian decision problems.

Multi-mode PolInSAR experiments using an airborne X-band SAR system in China

In this paper, we describe our polarimetric interferometric synthetic aperture radar (PolInSAR) experiments with high-resolution X-band data acquired by a multi-mode airborne SAR system over an area of Linshui in southern China. First, we introduce our latest multi-mode X-band airborne imaging radar system (Multi-Mode-XSAR), which integrates three operation modes of bistatic, ping-pong, and mixed. Then, the Multi-Mode-XSAR data set and the corresponding ground measurements in test areas are briefly described. Considering the characteristics of the Multi-Mode-XSAR imagery, a dual-baseline polarimetric interferometry (DPI) method is proposed in this article. The proposed method guarantees a high coherence on the full polarimetric data and combines the benefits of short and long baselines to facilitate the phase unwrapping and promote height sensitivity. Our PolInSAR experiment results demonstrate that the DPI method is capable of generating DSM with higher accuracy than other multi-baseline (MB) methods and the Multi-Mode-XSAR imagery has great potential in PolInSAR applications.

Bandwidth Sharing and Scan Scheduling in Multimodal Radar with Communications and Tracking

This paper addresses two issues related to multi-functional radio frequency (RF) systems: Bandwidth sharing between radar surveillance and communications, and scan scheduling during radar surveillance and radar tracking. Bandwidth is a very scarce commodity which must be managed with diligence for optimal system performance. Multi-objective optimization is used to arrive at solutions making the best use of available bandwidth between radar and communications. Bandwidth allocation for radar is based on the need to unambiguously resolve various scattering features of the target and their spatial arrangement. We divide the surveillance space into angular sectors and use fuzzy logic to arrive at priorities for each sector. We also consider the problem of scan scheduling between tracking and surveillance modes for the multimodal radar and introduce the concept of partial passes to increase the number of visits for tracking sectors. Static radar scheduling methods are used for specific target scenarios, while dynamic radar scheduling is introduced to periodically adapt the algorithm to the current target scenario. The algorithms are applied for representative target scenarios. Tracking is performed using the particle filter algorithm. The scheduling algorithms are analyzed using key performance parameters.

Design, Performance and Optimization for Multimodal Radar Operation

This paper describes the underlying methodology behind an adaptive multimodal radar sensor that is capable of progressively optimizing its range resolution depending upon the target scattering features. It consists of a test-bed that enables the generation of linear frequency modulated waveforms of various bandwidths. This paper discusses a theoretical approach to optimizing the bandwidth used by the multimodal radar. It also discusses the various experimental results obtained from measurement. The resolution predicted from theory agrees quite well with that obtained from experiments for different target arrangements.

Aerobraking at Venus: A science and technology enabler

Venus remains one of the great unexplored planets in our solar system, with key questions remaining on the evolution of its atmosphere and climate, its volatile cycles, and the thermal and magmatic evolution of its surface. One potential approach toward answering these questions is to fly a reconnaissance mission that uses a multi-mode radar in a near-circular, low-altitude orbit of ∼400km and 60–70° inclination. This type of mission profile results in a total mission delta-V of ∼4.4km/s. Aerobraking could provide a significant portion, potentially up to half, of this energy transfer, thereby permitting more mass to be allocated to the spacecraft and science payload or facilitating the use of smaller, cheaper launch vehicles.Aerobraking at Venus also provides additional science benefits through the measurement of upper atmospheric density (recovered from accelerometer data) and temperature values, especially near the terminator where temperature changes are abrupt and constant pressure levels drop dramatically in altitude from day to night.Scientifically rich, Venus is also an ideal location for implementing aerobraking techniques. Its thick lower atmosphere and slow planet rotation result in relatively more predictable atmospheric densities than Mars. The upper atmosphere (aerobraking altitudes) of Venus has a density variation of 8% compared to Mars' 30% variability. In general, most aerobraking missions try to minimize the duration of the aerobraking phase to keep costs down. These short phases have limited margin to account for contingencies. It is the stable and predictive nature of Venus' atmosphere that provides safer aerobraking opportunities.The nature of aerobraking at Venus provides ideal opportunities to demonstrate aerobraking enhancements and techniques yet to be used at Mars, such as flying a temperature corridor (versus a heat-rate corridor) and using a thermal-response surface algorithm and autonomous aerobraking, shifting many daily ground activities to onboard the spacecraft. A defined aerobraking temperature corridor, based on spacecraft component maximum temperatures, can be employed on a spacecraft specifically designed for aerobraking, and will predict subsequent aerobraking orbits and prescribe apoapsis propulsive maneuvers to maintain the spacecraft within its specified temperature limits. A spacecraft specifically designed for aerobraking in the Venus environment can provide a cost-effective platform for achieving these expanded science and technology goals.This paper discusses the scientific merits of a low-altitude, near-circular orbit at Venus, highlights the differences in aerobraking at Venus versus Mars, and presents design data using a flight system specifically designed for an aerobraking mission at Venus. Using aerobraking to achieve a low altitude orbit at Venus may pave the way for various technology demonstrations, such as autonomous aerobraking techniques and/or new science measurements like a multi-mode, synthetic aperture radar capable of altimetry and radiometry with performance that is significantly more capable than Magellan.

Radar: the evolution since World War II

Modern radar design has benefited from the evolution of specialized digital processing, allowing high resolution ground mapping, target identification, and target tracking under many conditions. Air-to-air interception makes use of complex decision processes to select from many modes that depend on the clutter backgrounds and flight profiles. Today's multimode radars provide this information for each task while minimizing distractions. Fire control radars support a wide selection of weapons, including cannons and guided missiles. This is possible because of advanced digital processing. In the interval since WW II, radar design evolved from vacuum tubes to semiconductors and then to massively integrated circuits. Computers specialized for fast Fourier transforms (FFTs) have revolutionized radar data processing. System reliability has improved from a few hours to hundreds of hours. Effective built-in test informs ground maintenance personnel of problems for easy maintenance and low failure rates reduce or eliminate field maintenance benches at forward locations. Airborne surveillance radars, such as AW ACS Joint Stars have changed the nature of warfare. Commanders have virtually full view of enemy and friendly forces. Radars, in combination with other remote sensors, provide precise weapon delivery, reducing collateral damage and making all weapons more effective.

Target motion analysis using range-only measurements: algorithms, performance and application to ISAR data

The paper considers the problem of target motion analysis from range and range-rate target measurements. The motivation for this work comes from the need to track the target motion with the Ingara multi-mode radar during an extended data collection in the ISAR mode. The paper makes three main contributions. First, the theoretical Cramér–Rao bound for the performance of an unbiased range-only tracking algorithm is derived. Second, three algorithms for target motion analysis (using range and range-rate measurements only) are developed and compared to the theoretical bounds of performance. The three algorithms are: the maximum likelihood estimator, the extended Kalman filter and the regularised particle filter. Finally, the paper presents the results of the application of the developed theory to the ISAR data collected in the recent trials with the Ingara radar.

Low-cost technology for multimode radar

A flexible test bed radar architecture is described which includes an integrated RF electronics package that can support multiple radar applications, including surveillance, fire control, target acquisition, and tracking. This type of architecture can significantly reduce the cost, power, size, and weight of electronics on future weapon delivery platforms. The Army Research Laboratory (ARL) is developing technology to support multimode radar requirements. These requirements include the detection and location of moving or stationary low radar cross section targets in heavy ground clutter and the classification and/or recognition of these targets. We address these requirements with commercial-off-the-shelf (COTS) products and the integration of several enabling technologies. The test bed radar includes a direct digital synthesizer (DDS) for frequency-diverse waveform generation, a flexible wideband transceiver for bandwidth extension and frequency translation, and an open architecture signal processor with embedded wideband analog-to-digital converters for real-time acquisition and processing. Efficient signal processing algorithms have been developed to demonstrate multimode radar capability. This paper discusses the various subassemblies, algorithm efficiency, and field experiment results.

Smuggling interdiction using an adaptation of the AN/APG-76 multimode radar

The AN/APG-76 multimode radar was designed and developed for a multimode attack fighter application requiring rapid search, detection, identification, and precision location of both airborne and surface targets from long standoff ranges under adverse weather conditions. Unique is the radar's ability to generate SAR images of a selected area while simultaneously detecting and tracking all-speed moving objects located within that imaged region. Northrop Grumman Norden Systems has recently upgraded and adapted this radar to smuggling interdiction and related law enforcement missions. These adaptations have added an integrated GPS/INS subsystem for enhanced self-navigation and target location accuracy, a long range wide-band digital data link and ground station for mission control and data dissemination, a 3-D interferometric SAR imaging capability for detailed high resolution topographic mapping, and 1 meter and 0.3 meter resolution SAR modes for positive target identification. Additionally, the radar has been installed into wing-mounted pods and adapted for side-looking and 360 degree coverage applications. Automatic target detection and enhanced-range sea-surveillance and air-targeting modes are also now available through the use of open architecture commercial processors and non-proprietary transportable programming languages.

Magellan imaging radar mission to Venus

The Magellan imaging radar mapping mission has collected and processed data from the spacecraft in an elliptical orbit around Venus. A brief description is given of the mission and the spacecraft, followed by a more detailed description of the radar system design, which used Earth-orbiting synthetic aperture radar (SAR) experience and several innovations in its design to operate from an orbit around another planet. The radar sensor, ground processing, and data products are described. This multimode radar is the only science instrument on the mission and has the objective of mapping at least 70% of the planet surface. It has three modes: SAR, altimetry, and passive radiometry. The radar system has produced maps of almost all of the Venusian surface with a resolution better than 600 m equivalent optical line pair, and the best resolution obtained is equivalent to less than 300 m. Some of the early radar images are shown.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>