Primary Radar Research Articles

Edge clutter rejection for PPI radar images

Purpose Incoherent primary radar is an applicable means for security surveillance of low-altitude airspace. An experimental airspace surveillance radar system has been developed for such applications. Target detector based on radar images is a powerful technique for the system. The main difficulty in designing such a detector is the rejection of heavy edge clutter for the plane position indicator (PPI) radar images after background subtraction.

Preliminary Waveform Analysis for a New Concept of ATC Radar

The expected growth of air traffic in national and international airports requires the development of new, efficient air traffic management systems. A key objective is to develop new technologies for maximizing airspace and airport capacity and safety. The availability of accurate ground condition information, regardless of the information independently acquired by the aircraft or that provided by the controller via voice channel, is believed to be of considerable interest in increasing landing security. Currently, the radar surveillance function and the communication function toward approaching aircrafts are carried out separately: the airport's primary surveillance radar performs surveillance, while dedicated radio channels in the VHF band allow air-ground voice communications. In this context, this paper explores the possibility of combining the traditional tracking function performed by radar with the communication function, which automatically provides aircrafts, monitored near real time, with a series of data particularly useful for the final landing. The data at issue are typically those related to airport ground conditions, such as local air-meteorological conditions and airport runway management. This information is integrated into the waveform emitted by the radar, thus implementing a broadcast transmission channel, whose content can be automatically decoded by an aircraft equipped with an appropriate receiving system. The proposed study is a preliminary analysis of the topic, with the main purpose of assessing the feasibility of using radar and communication techniques in this particular application.

High-Power Wideband $L$-Band Suboptimum Class-E Power Amplifier

This paper presents a high-power high-efficiency wideband suboptimum Class-E RF power amplifier based on a packaged high-power GaN HEMT. It uses a simple double-reactance compensation and impedance transformation load network that includes device intrinsic capacitance, package parasitics, low-loss microstrip transmission lines, and lumped components. This load network makes the GaN HEMT operate in suboptimum Class-E from 900 to 1500 MHz (50% fractional bandwidth at 1200 MHz). The amplifier can operate both in continuous wave and pulsed modes over its full bandwidth without tuning. It delivers up to 180-W output power with up to 85% drain efficiency and PAE=81%. To the best of the authors' knowledge, the amplifier proposed in this work outperforms commercial grade amplifiers that operate in the same frequency band with similar output power levels. Direct applications for this amplifier include mobile satellite communications transmitters, envelope elimination and restoration digital audio broadcasting transmitters, and power stages for primary and secondary RADAR transmitters.

Radio Aurora Explorer: A Mission Overview

The primary objective of the Radio Aurora Explorer mission is to study plasma instabilities that lead to magnetic field aligned irregularities of electron density in the lower polar ionosphere (80–400 km). These irregularities are known to disrupt communication and navigation signals. The Radio Aurora Explorer mission uses a bistatic radar configuration; the spacecraft is the radar receiver and the transmitters are several worldwide incoherent scatter radars of which the primary radar is located in Poker Flat, Alaska. The satellites are 3 kg, university-class CubeSats with a primary payload of a direct-conversion radar receiver operating in the frequency range from 426 to 510 MHz. The satellite bus has a novel configuration of processing, attitude control, and antenna design that met the physical constraints of the CubeSat form factor and the one-year schedule constraint imposed by launch dates. Two satellites have launched: RAX-1 on 19 November 2010 onboard a Minotaur-IV rocket from Kodiak, Alaska, and RAX-2 on 28 October 2011 onboard a Delta-II rocket from Vandenberg U.S. Air Force Base, California. RAX-2 has detected and measured irregularities during multiple experiments over Alaska and Canada. Preliminary analysis indicates unprecedented characterization of the irregularities.

Modeling and Simulation of a Ground Based Sense and Avoid Architecture for Unmanned Aircraft System Operations

The safe operation of Unmanned Aircraft Systems (UAS) in the National Airspace System necessitates a capability to sense and avoid other airborne objects. One solution is a Ground Based Sense and Avoid (GBSAA) concept, where data from ground-based radars are fused in a specially tuned tracking system that can provide traffic information to manual (flight crews) or automatic collision avoidance systems. In this paper, we will present a modeling and simulation approach to assess site-specific radar detection and tracking performance. High fidelity primary surveillance radar and tracking system models enable simulation studies to determine target probability of detection and distributions of expected track initiation times across the surveillance volume. Atmospheric and environmental conditions, terrain, and land coverage type affect radar wave propagation. Models take into account these sources of degradation, as well as target characteristics, site-specific radar performance, tracking system filtering, and initiation logic. This information will help in developing a GBSAA concept of operation, mission planning, and will ultimately define where UAS can operate with sufficient surveillance performance to meet sense and avoid requirements.

FUZZY LOGIC-BASED TARGET CLASSIFICATION USING KINEMATIC DATA

The need for fast and accurate decisions in activities related to air surveillance and control has led to the development of systems to reduce operators' workload. In this context, a solution for aerial target classification is presented, using kinematic data (speed and acceleration) as input parameters. These can be estimated by a system composed of primary surveillance radar and a tracking algorithm. The implemented classifier is based on a fuzzy inference system that is capable of giving in real-time the membership degrees of a target to three defined classes, which is useful in the absence of data from secondary/IFF (Identification Friend or Foe) radars or imaging sensors.

Beacon Tracking System and Its Performance in Search Operation for Hayabusa Sample Return Capsule

Hayabusa returned to Earth on June 13, 2010, becoming the world's first explorer to complete a round-trip voyage to an asteroid. After being released from the spacecraft, the sample return capsule landed in the Woomera Prohibited Area in the desert of South Australia. The capsule recovery team from JAXA found the capsule within 1 h of its landing. The beacon tracking system that was developed by JAXA played an important role in the tracking and discovery of the sample return capsule. The system has flexibility regarding the landing position of the capsule, because it does not rely on primary radar. In this paper, we describe the beacon tracking system and evaluate the system by discussing the results of preliminary examination and of operation on the day of re-entry.

Measurement of electromagnetic fields generated by air traffic control radar systems with spectrum analysers

Air traffic control (ATC) primary radars are 'classical' radars that use echoes of radiofrequency (RF) pulses from aircraft to determine their position. High-power RF pulses radiated from radar antennas may produce high electromagnetic field levels in the surrounding area. Measurement of electromagnetic fields produced by RF-pulsed radar by means of a swept-tuned spectrum analyser are investigated here. Measurements have been carried out both in the laboratory and in situ on signals generated by an ATC primary radar.

Advancing the Science of Primary Care Pain Medicine

Primary care providers (PCPs) should be well-positioned to deliver excellent care for patients with chronic pain. We specialize in the long-term care of the whole patient and are expert in the management of chronic disease. Chronic pain conditions are among the most common problems seen in primary care [1]. Furthermore, if opioid prescribing is a marker for attention to pain, we have good evidence that pain is increasingly on the primary care radar screen [2,3]. However, research has demonstrated deficits in the quality of primary care pain treatment [4]. Why do we often fall short in providing optimal pain management in primary care? In this issue, Dobscha et al. provide evidence that most often it is not because of a lack of interest or concern about treating pain [5]. In their survey of 45 PCPs practicing in five clinics affiliated with one Veterans Administration (VA) Medical Center, they found that a large majority believed skilled pain management was a high priority and were confident in their abilities to treat chronic pain. The study confirms that opioid prescribing has become a routine part of primary care practice; in the average provider panel, one of six patients had a current opioid prescription. Primary care providers …

STUDY ON THE CONSTRUCTION OF THE OPERATIONAL RAINFALL ESTIMATE ALGORITHM WITH THE LATEST C-BAND POLARIMETRIC RADAR

Improvement of quantitative precipitation estimation (QPE) is one of the primary benefits providedbypolarization radars. Ministryof Land, Infrastructure and Transportation Japan (MLIT) put Shakadakeoperational Cband Radar to practical use in1992. However, large improvement hadnotbeenrealizedbecause of its initial technical stage.Under these circumstances, first, this paper compares the performance of the conventional R (ZHH) relation and three polarimetric relations, which are R (ZHH, ZDR), R (KDP), R (KDP, ZDR) . At lower rainrates, the combinationof KDP and ZDR is less efficient because KDP becomes noisy. Next in order to improveQPE, a few combinations of estimation equations for operational purpose is proposed, considering thecharacteristic ofthose relations. Also validations with some other algorithms are conducted. As a result, the proposed algorithms improve the estimationof hourly rainfall and accumulated total rainfall.

Evaluating Controller Use of Advanced Weather Products by Evaluating User Interaction Patterns

We evaluated how Terminal Radar Approach Control (TRACON) controllers interacted with advanced weather products when displayed on primary tactical radar displays or on auxiliary flat-panel displays. When we provide the controllers with access to appropriate weather tools, we potentially decrease workload and improve performance by increasing weather situational awareness (WSA). We assessed the benefit of providing weather information using Gantt charts to graphically depict user interaction patterns and by conducting an analysis of the frequency and duration of interactions with the weather tools. From these analyses, we identified two patterns of interacting with tools corresponding to heavy and light users. We correlated tool use with our measure of controller efficiency and found an increase in traffic throughput with increasing tool use. We also determined that the controllers were more likely to interact tactically with tools when placed on the Terminal Controller Workstation (TCW), turning them on when needed and turning them off when not needed. This method provides us with insight into how the controllers use the information on their displays to help provide them with tools to increase safety and efficiency.

Design of a space-based radar signal processor

Space-based radar (SBR) is capable of providing flexible wide-area coverage of air, land, and sea targets. Numerous studies have been carried out in the United States and Canada in recent years to investigate different concepts for SBR. The design of a suitable radar signal processor (RSP) is challenging due to the effects caused by the moving platform on target integration and clutter spectral spread. A candidate RSP is described that uses a corporate fed array (CFA) antenna as its primary radar sensor. The algorithmic definitions of the signal processing functions are provided; the relationships between these functions and the reasons for their location in the signal processing chain are also discussed. In addition, techniques for reducing the computational requirements are also presented.

Applying nondestructive remote sensing techniques to hazardous waste management

The ever-increasing concern of property owners, potential property owners, real estate lawyers, and all others associated with the selling and purchasing of such properties, has led to an overwhelming demand for accurate, efficient, and economical site assessment programs. The overriding concern for the majority of these individuals is the possibility of underground storage tanks (UST's), waste deposits, and/or contaminated subsurface soils that may be located at the site. Depending on the nature of the purchase, the location or confirmation of buried waste will be a deciding factor in the decision to purchase toe proposed property. Due to the overwhelming cost of remediation of contaminated sites, and these costs being the sole responsibility of the property owner, it is imperative that the existence and amount of any subsurface contaminants be known prior to the purchase of the property. The recent introduction of two testing techniques has led to a viable solution for dependable, cost effective location and characterization of underground waste deposits. This testing procedure uses infrared thermography as a primary testing method and ground penetrating radar as a secondary investigation technique. Both technologies have been proven effective in numerous nondestructive testing (NDT) applications for many years. However, few companies havemore » fused these technologies to incorporate data results and the testing advantages of each technology for locating and characterizing subsurface waste sites. This method of data fusion has proven to be accurate and cost-effective for gaining detailed information pertaining to subsurface conditions of both large and small sites.« less

Air Navigation Systems Chapter 5. The Development of British Airborne Primary Radar, 1935–1945

This paper is the fifth chapter of a series on the history of air navigation systems. Comments on the content of the paper would be welcomed by the author and the editor.

A novel noncooperative near-range radar network for traffic guidance and control on airport surfaces

The concept of a novel modular structured near-range primary radar network (NRN) for guidance and control of airport surface traffic is presented. Several autonomously operating modules comprising of four radar stations cover all relevant airport areas or, alternatively, are integrated in a complex structured surveillance system by data fusion; then only selected areas have to be covered. Each sensor of a single module illuminates a common area of surveillance by a fixed, non-rotating antenna and measures range echo profiles. For the utilization within a planning and alert system the target locations inside a module are derived from multilateration of echo ranges, measured by multiple distributed sensors. Target velocity vectors are evaluated from the time history of several range echo profiles at least at two stations; target classification is obtained from microwave imaging techniques. In order to demonstrate the performance of the location technique and its flexibility in adapting to different airport scenarios, simulation results are presented. The location simulations are based on high-resolution radar cross-section measurements of a downscaled A-310 aircraft model. >

Contracts

The Civil Aviation Administration of Norway (Luftfartsverket) has awarded a contract valued at approximately £4m to Cossor for the first phase of the Norwegian Radar Project. The scope of the contract is to supply Monopulse Secondary Surveillance Radar and Primary Radar for three sites with options for six further sites.

Polish radar technology

Polish radar research and development since 1953 is reviewed, covering the development and production of surveillance radars, height finders, tracking radars, air traffic control (ATC) radars and systems, and marine and Doppler radars. Some current work, including an L-band ATC radar for enroute control, a weather channel for primary surveillance radar, signal detection in non-Gaussian clutter, adaptive MTI filters and postdetection filtering, and a basic approach to radar polarimetry, is examined.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

I – Improvements to Secondary Radar for Air Traffic Control

Secondary surveillance radar (SSR) is nearly as old as radar itself. It has evolved from a need in the last war for an Identification system between Friend and Foe (IFF)Primary radar has a scanning aerial beam which transmits a burst of energy, and the reflected signal from an aircraft is detected. In the simplest form of IFF the aircraft carries a receiver/transmitter (transponder), which detects the primary radar beam and transmits a pulse (on the same frequency) a few microseconds later. Thus two ‘blips’ appear on the radar display, one at the shorter range due to reflected energy from the aircraft followed by a stronger reply from the transponder. The system requires all aircraft to carry a transponder which upon receipt of an ‘up link’ signal or message transmits a ‘down link’ signal or message. SSR has evolved (and is still evolving) from this early IFF technique into the present-day system which serves both military IFF needs and the requirements for Air Traffic Control. This paper concentrates on the civil use of SSR where it is the prime sensor for the control of aircraft.

Multipath and interference effects in secondary surveillance radar systems

Secondary surveillance radar (SSR) offers many advantages for air traffic control (ATC) compared to normal (or primary) radar including substantially lower cost and improved performance. Because of the increasing reliance being placed on SSR by ATC a number of the system problems associated with SSR are becoming less easily tolerated. The paper discusses these problems, which mainly arise from multipath and mutual interference effects, and proposes solutions.

Survey of radar data-processing techniques in air-traffic-control and surveillance systems

The application of data-filtering techniques for air-traffic-control and surveillance systems is re-reviewed. Operational requirements of these systems are primarily described. They are typically composed of radars (mechanical scanning and phased array), data-processing devices (digital computers) and displays. The environment is determined by the number and characteristics of targets and by the density and characteristics of the unintentional (weather, etc.) and intentional interferences. The effect of the environment on the filtering techniques used is also considered. In the case of air traffic control, a(α, β) filtering algorithm, which is used for primary radars, secondary radars and d.a.b.s. (discrete address beacon systems) is described. Collision-avoidance techniques and their implementation are also mentioned. In the case of air defence and surveillance systems, the algorithms are more sophisticated because of unpredictable target motion, high acceleration and intentional interferences. The types of algorithms which may be employed are the Kalman filter (also with variable data rate for phased-array radar), adaptive filters for manoeuvring targets, filters for target tracking in clutter and jamming environment, a filter for tracking of targets formations and, finally, nonlinear filters using radial velocity information. Moreover, the above mentioned techniques affect fire-control and interceptor-guidance methods. The filtering methods are extended to the multiradar case. Some specific problems, which are herein emphasised, concern the ways of combining the information coming from the different radars, the measurement time alignment and co-ordinate conversion over large areas. The methods of filter implementation, being affected by the technology available, are also described. Finally, a comprehensive list of references, refering to the different topics, has been included.