Applications of TVF-EMD in Vital Signal Detection for UWB Radar

When using pulsed ultra-wideband radar (UWB) noncontact detection technology to detect vital signs, weak vital signs echo signals are often covered by various noises, making human targets unable to identify and locate. To solve this problem, a new method for vital sign detection is proposed which is based on impulse ultra-wideband (UWB) radar. The range is determined based on the continuous wavelet transform (CWT) of the variance of the received signals. In addition, the TVF-EMD method is used to obtain the information of respiration and heartbeat frequency. Fifteen sets of experiments were carried out, and the echo radar signals of 5 volunteers at 3 different distances were collected. The analysis results of the measured data showed that the proposed algorithm can accurately and effectively extract the distance to the target human and its vital signs information, which shows vast prospects in research and application.

Simulation of Pulse-Echo Radar for Vehicle Control and SLAM

Pulse-echo sensing is the driving principle behind biological echolocation as well as biologically-inspired sonar and radar sensors. In biological echolocation, a single emitter sends a self-generated pulse into the environment which reflects off objects. A fraction of these reflections are captured by two receivers as echoes, from which information about the objects, such as their position in 3D space, can be deduced by means of timing, intensity and spectral analysis. This is opposed to frequency-modulated continuous-wave radar, which analyses the shift in frequency of the returning signal to determine distance, and requires an array of antenna to obtain directional information. In this work, we present a novel simulator which can generate synthetic pulse-echo measurements for a simulated sensor in a virtual environment. The simulation is implemented by replicating the relevant physical processes underlying the pulse-echo sensing modality, while achieving high performance at update rates above 50 Hz. The system is built to perform design space exploration of sensor hardware and software, with the goals of rapid prototyping and preliminary safety testing in mind. We demonstrate the validity of the simulator by replicating real-world experiments from previous work. In the first case, a subsumption architecture vehicle controller is set to navigate an unknown environment using the virtual sensor. We see the same trajectory pattern emerge in the simulated environment rebuilt from the real experiment, as well as similar activation times for the high-priority behaviors (±1.9%), and low-priority behaviors (±0.2%). In a second experiment, the simulated signals are used as input to a biologically-inspired direct simultaneous mapping and localization (SLAM) algorithm. Using only path integration, 83% of the positional errors are larger than 10 m, while for the SLAM algorithm 95% of the errors are smaller than 3.2 m. Additionally, we perform design space exploration using the simulator. By creating a synthetic radiation pattern with increased spatiospectral variance, we are able to reduce the average localization error of the system by 11%. From these results, we conclude that the simulation is sufficiently accurate to be of use in developing vehicle controllers and SLAM algorithms for pulse-echo radar sensors.

Electromagnetic-mechanical repair patch of radar-absorbing structure with electroless nickel–plated glass fabric damaged by lightning strike

This paper presents an electromagnetic-mechanical repair patch (EMRP) to restore the mechanical and electromagnetic (EM) wave absorption performance of a radar-absorbing structure (RAS) damaged by lightning strike. Several researchers have primarily focused on ensuring high repair efficiency, particularly in terms of the primary load-bearing properties of repaired fiber-reinforced plastics. However, no study has proposed a practical repair approach that considers the multi-functionality of the radar-absorbing structure. The EMRP method can be used to repair lightning strike damage in a radar-absorbing structure with electroless nickel-plated glass fabric, considering the need to maintain structural integrity and electrical continuity to achieve a high repair efficiency. Damage due to an artificial lightning strike was assessed in terms of area and depth of the damage using image processing, ultrasonic C-scan, and micro X-ray inspection. The EM characteristics of one-dimensional return loss scanning and the echo radar-cross-section level were measured to verify the stealth performance of the repaired radar absorber in the X-band. In addition, the tensile test results demonstrated that the repaired radar absorber had a high recovery rate of 93% compared to the pristine radar absorber. The experimental results obtained in this study validate the use of the proposed EMRP method in repairing radar-absorbing structures.

The Mesoscale Convective Systems with bow echo radar signatures as an example of extremely severe and widespread geohazard in Poland

In the last two decades we can notice a significant increase of severe anemological events, which are mostly connected with mesoscale convective systems and a cold front of a deep low-pressure system. One of them are very strong winds with speeds more than 25 m/s. They caused material damage and threatening people's lives. The most dangerous are winds generated by mesoscale convective systems where radar reflectivity signatures of bow echo/derecho appeared. In this paper the area of occurrence of such phenomenon in Poland are described and the features of bow echo signatures on radar images are presented and explained. Additionally one of the most severe event and still very weakly known episode of 11th August 2017 derecho in Poland is analysed. The damage data from European Severe Weather Database (ESWD) were analysed to confirm if the August 11th storm met derecho criteria. To identify the radar reflectivity signatures inside MCC the data from the Polish Institute of Meteorology and Water Management shared on the radar-opadow.pl site were used. The CAPPI 1 km data were very useful to determine the convective forms. After that the data from synoptic station were examined for presenting the running of selected meteorological elements. Finally, some information about material damage in infrastructures and forests are mentioned.

METODE PENCUPLIKAN NILAI ECHO CITRA RADAR *.PNG DENGAN REFERENSI SPASIAL DAN KOMBINASI WARNA RGB

IntisariData meteorologi yang berupa citra/gambar sulit dianalisis dan dikombinasikan dengan data lain. Dalam karya tulis ini akan dijelaskan metode pencuplikan citra/gambar radar yang dipublikasikan oleh BMKG menjadi data teks. Proses pengolahan terdiri dari dua tahap yaitu proses pemetaan setiap pixel dalam citra radar menjadi koordinat bumi (latitude dan longitude) dan penentuan nilai echo radar (dBZ). Dari legenda pada citra radar didapatkan 9 pola warna RGB yang digunakan sebagai penentu nilai dBZ setiap pixel dalam citra radar. Hasil pengolahan citra radar berupa data teks yang terdiri dari longitude, latitude, dan nilai dBZ. Untuk membandingkan dengan data asli, data radar teks hasil pengolahan ditampilkan pada Website Global Informasion System (WebGIS). Warna data radar pada WebGIS ditentukan dengan persamaan warna sebagai fungsi dari nilai dBZ. Secara kualitatif, hasil perbandingan gambar radar asli dengan data numerik yang ditampilkan pada WebGIS menunjukkan bahwa hasil data numerik cukup presisi pada posisi longitude dan latitude. Namun, dari segi nilai numerik echo radar (dBZ) yang dihasilkan terdeteksi kurang akurat pada batas awan karena latar belakang gambar yang berwarna hitam. Selain itu, pada keterangan nama kota dan batas wilayah yang berwarna abu-abu menujukkan pixel yang kosong walaupun disekelilingnya terlihat adanya awan, sehingga diperlukan penelitian lebih lanjut untuk mengatasi permasalahan tersebut dengan menambahkan filter untuk mengoreksi nilai pixel pada batas gambar dan teknik interpolasi untuk mengisi kekosongan nilai pada area pixel. AbstractMeteorological data in the form of image has difficulty in further analysis such as to combine the data with other data sources. In this research, the proposed method for converting image data into texts using image processing for BMKG data provided is presented. The processing scenarios consist of two main steps; mapping process of every pixel of the images into the earth coordinate (latitude and longitude) step and radar echo values estimation in dBZ step. From the analysis, the 9 color patterns of RGB are obtained and used as the dBZ justification tool for the pixel color of radar image. The results of this image processing step are the texts data of latitude, longitude and the radar echo values in dBZ. In order to compare the analysis results with the original data, the processing data are then reshown to global information system website (WebGIS). The radar color data on WebGIS is determined based on color equation as a function of the echo radar. Qualitatively, the results of this comparison show that the numerical data results are precise in terms of longitude and latitude positions. However, in terms of numerical values echo radar (dBZ), the results perform less accurate especially on the boundary of the cloud due to the black color of background image. In addition, the description of the city name and the border of the gray area show the data are empty although by visual inspection there are surrounding clouds. Thus, further research is needed to solve the problem by adding filters to correct the pixel value at the image boundary and applying the interpolation technique to fill the void value in the pixel area.

The Geminid meteor shower during the ECOMA sounding rocket campaign: specular and head echo radar observations

The ECOMA (Existence of Charge state Of meteoric smoke particles in the Middle Atmosphere) sounding rocket campaign was conducted during the Geminid meteor shower in December 2010 in order to explore whether there is a change of the properties of meteoric smoke particles due to the stream. In parallel to the rocket flights, three radars monitored the Geminid activity located at the launch site in Northern Norway and in Northern Germany to gain information about the meteor flux into the atmosphere. The results presented here are based on specular meteor radar observations measuring the radiant position, the velocity and the meteor flux into the atmosphere during the Geminids. Further, the MAARSY (Middle Atmosphere Alomar Radar System) radar was operated to conduct meteor head echo experiments. The interferometric capabilities of MAARSY permit measuring the meteor trajectories within the radar beam and to determine the source radiant and geocentric meteor velocity, as well as to compute the meteor orbit.