scholarly journals Design of Optimized Coded LFM Waveform for Spectrum Shared Radar System

Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5796
Author(s):  
Dong-Hoon Kim ◽  
Hyung-Jung Kim ◽  
Jae-Han Lim
Keyword(s):  
Remote Sensing ◽  
Computer Simulations ◽  
Cross Correlation ◽  
Signal Transmission ◽  
Radar System ◽  
Weighted Sum ◽  
Simple Scheme ◽  
Optimization Framework ◽  
Radar Systems ◽  
Orthogonal Codes

To meet the increasing demands for remote sensing, a number of radar systems using Linear Frequency Modulation (LFM) waveforms have been deployed, causing the problem of depleting frequency resources. To address this problem, several researchers have proposed the Spectrum Shared Radar System (SSRS) in which multiple radars share the same frequency band to transmit and receive their own signals. To mitigate the interferences caused by the signal transmission by other radars, SSRS employs orthogonal waveforms that inherit the orthogonality of the waveforms from orthogonal codes. However, the inherited orthogonality of the codes is significantly reduced when incorporating LFM waveforms with the codes. To solve this problem, in this paper, we propose a novel but simple scheme for generating a set of optimized coded LFM waveforms via new optimization framework. In the optimization framework, we minimize the weighted sum of autocorrelation sidelobe peaks (ASP) and cross-correlation peaks (CP) of the coded LFM waveforms to maximize the orthogonality of the waveforms. Through computer simulations, we show that the waveforms generated by the proposed scheme outperform the waveforms created by previous proposals in terms of ASP and CP.

UAV Radar imaging for cultural heritage: a first prototype

2020 ◽  
Author(s):  
Carlo Noviello ◽  
Giuseppe Esposito ◽  
Ludeno Giovanni ◽  
Gennarelli Gianluca ◽  
Fasano Giancarmine ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Data Processing ◽  
Cultural Heritage ◽  
Scattering Problem ◽  
Radar Imaging ◽  
Radar System ◽  
Unmanned Aircraft ◽  
Electromagnetic Spectrum ◽  
Differential Gps ◽  
Radar Systems

<p>Nowadays, the use of Unmanned Aircraft Vehicle (UAV) based sensing technologies is widely considered in most disparate fields, including archaeology and cultural heritage inspections. The main advantages offered by UAV technology are the possibility of investigating large areas in a very short time,  the simplification of the organization and implementation of the measurement campaigns thus reducing their costs, and finally the increasing availability of autonomous systems that push more and more towards plug and fly solutions.</p><p>The widespread remote sensing technologies mounted on-board UAV systems are essentially optical, thermal and multi-spectral sensors, which are passive technologies designed to measure the signal emitted into the optical and (near and far) infrared portions of the electromagnetic spectrum. These technologies exploit techniques like aero-photogrammetry to get high resolutions images of the surface features of the investigated scene and provide useful information to evaluate structural and material degradation, such as surface cracks, humid zones and biological patinas.</p><p>Radar systems represent a further technological solution, which exploits the penetration capability into non-metallic media of the microwaves, thus offering the key advantage to perform surface and sub-surface inspections. However, UAV based radar systems are still under development due to the numerous challenges related to the acquisition modality and data processing. Being radar an active technology, both transmitting and receiving units must be installed on-board the UAV and this introduces not trivial issues related to payload and assets constrains. Moreover, in order to obtain focused images, a high precision knowledge of the UAV position during its flight must be available.</p><p>As a contribution to this topic, an ultra-light radar system mounted on a micro drone has been developed and its imaging capabilities have been assessed in controlled conditions. The UAV radar imaging system is an enhanced version of that presented in [1]. Specifically, the main components of the assembled prototype are the UAV DJI F550- hexacopter platform and the Pulson P440 radar sensor. The radar system has been equipped with two log-periodic antennas pointed at nadir, and it operates in the frequency range of [3.1, 4.8] GHz. Moreover, to accurately reconstruct the UAV platform positioning, the Differential GPS technology has been also implemented by exploiting two GPS receivers placed one onboard the platform and the other one in a fixed ground station. Finally, the data processing is cast as the solution of an inverse scattering problem by exploiting the Born Approximation to model the wave-material interaction. The results of some flight tests will be presented at the conference.</p><p>[1] G. Ludeno, I. Catapano, A. Renga, A. Vetrella, G. Fasano, and F. Soldovieri, “Assessment of a micro-UAV system for microwave tomography radar imaging”, Remote Sensing of Environment, vol 212, 2018, pp. 90-102.</p><p>Acknowledgment: The authors would like to thank the VESTA project “Valorizzazione E Salvaguardia del paTrimonio culturAle attraverso l’utilizzo di tecnologie innovative” by which the present work has been financed.</p><p> </p>

scholarly journals Real-Time Tsunami Detection with Oceanographic Radar Based on Virtual Tsunami Observation Experiments

2018 ◽  
Vol 10 (7) ◽  
pp. 1126 ◽  
Author(s):  
Kohei Ogata ◽  
Shuji Seto ◽  
Ryotaro Fuji ◽  
Tomoyuki Takahashi ◽  
Hirofumi Hinata
Keyword(s):  
Real Time ◽  
Detection Probability ◽  
Cross Correlation ◽  
Temporal Change ◽  
Detection Method ◽  
Radar System ◽  
Hf Radar ◽  
Tsunami Detection ◽  
Radar Systems ◽  
First Time

The tsunami generated by the 2011 Tohoku-Oki earthquake was the first time that the velocity fields of a tsunami were measured by using high-frequency oceanographic radar (HF radar) and since then, the development of HF radar systems for tsunami detection has progressed. Here, a real-time tsunami detection method was developed, based on virtual tsunami observation experiments proposed by Fuji et al. In the experiments, we used actual signals received in February 2014 by the Nagano Japan Radio Co., Ltd. radar system installed on the Mihama coast and simulated tsunami velocities induced by the Nankai Trough earthquake. The tsunami was detected based on the temporal change in the cross-correlation of radial velocities between two observation points. Performance of the method was statistically evaluated referring to Fuji and Hinata. Statistical analysis of the detection probability was performed using 590 scenarios. The maximum detection probability was 15% at 4 min after tsunami occurrence and increased to 80% at 7 min, which corresponds to 9 min before tsunami arrival at the coast. The 80% detection probability line located 3 km behind the tsunami wavefront proceeded to the coast as the tsunami propagated to the coast. To obtain a comprehensive understanding of the tsunami detection probability of the radar system, virtual tsunami observation experiments are required for other seasons in 2014, when the sea surface state was different from that in February, and for other earthquakes.

scholarly journals Deteksi Radar Pasif menggunakan GNU Radio dan SDR pada Frekuensi Televisi

2020 ◽  
Vol 8 (3) ◽  
pp. 505
Author(s):  
YONATAN EDWIN MARPAUNG ◽  
ALOYSIUS ADYA PRAMUDITA ◽  
ERFANSYAH ALI
Keyword(s):  
Software Defined Radio ◽  
Cross Correlation ◽  
Moving Objects ◽  
Radar System ◽  
Digital Television ◽  
Passive Radar ◽  
Gnu Radio ◽  
Delay Test ◽  
Radar Systems ◽  
Television Receiver

ABSTRAKRadar pasif adalah salah satu jenis sistem radar bistatic dimana transmitter dan receiver berada di tempat berbeda. Sistem radar pasif dapat memaanfaatkan frekuensi siaran televisi yang tersedia sebagai sumber transmitter. Pada penelitian ini, radar pasif dibuat dengan Sofware Defined Radio (SDR) sebagai sistem komunikasi yang dapat mengkofigurasi penerima televisi digital sdr-dongle RTL2832U yang dimodifikasi dan perangkat lunak GNU Radio. Hasil pengujian delay pada gelombang 1,2,3 untuk objek manusia adalah 0,192, 0,36 dan 0,53 detik, untuk objek sepeda adalah 0,332, 0,5 dan 0,67, untuk objek motor adalah 0,422, 0,69 dan 0,86 detik, untuk objek mobil adalah 0,538, 0,7 dan 0,87 detik sehingga dapat disimpulkan bahwa sistem radar pasif yang dirancang dapat mendeteksi benda bergerak dimana pegerakan target menyebabkan pergeseran puncak Cross-Correlation.Kata kunci: Radar Pasif, Cross-Correlation, SDR, Frekuensi Televisi, RTL2832U ABSTRACTPassive radar is a type of bistatic radar system where the transmitter and receiver are in different places. Passive radar systems can utilize the available television broadcast frequencies as transmitter sources. In this study, passive radar is made with Software Defined Radio (SDR) as a communication system that can configure a modified RTL2832U sdr-dongle digital television receiver and GNU Radio software. The delay test results on waves 1,2,3 for human objects are 0.192, 0.36 and 0.53 seconds, for bicycle objects are 0.332, 0.5 and 0.67, for motor objects are 0.422, 0.69 and 0.86 seconds, for car objects are 0.538, 0.7 and 0.87 seconds so it can be concluded that the passive radar system is designed to detect moving objects where moving targets causes a shift in the peak of Cross-Correlation.Keywords: Passive Radar, Cross-Correlation, SDR, Television Frequency, RTL2832U

FEATURES OF CONSTRUCTION OF ON-BOARD HELICOPTER RADAR ICE EXPLORATION ON BASIS OF CIRCULAR GROUND SURFACE WITH SYNTHESIS OF APERTURE ROTATING ANTENNA

2019 ◽  
pp. 31-37
Author(s):  
I. G. Antсev ◽  
A. P. Aleshkin ◽  
V. V. Vladimirov ◽  
E. O. Kudrina ◽  
O. L. Polonchik ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Ground Surface ◽  
Rotor Blades ◽  
Navigation Systems ◽  
Propeller Blade ◽  
Antenna Aperture ◽  
Sensing System ◽  
Radar Systems ◽  
Simulation Results ◽  
Circular Antenna Array

The results of modeling the processes of receiving and processing the signals of remote sensing of the Earth’s surface using helicopter radar and synthesizing the antenna aperture due to its placement on the rotating rotor blades are presented. The mathematical correctness of the application of the developed algorithms for processing probing signals, as well as the uniqueness of the measurements, was confirmed. At the same time, the dimensions of the synthesized aperture due to the rotation of the radiator placed at the end of the propeller blade are equivalent to a circular antenna array with a diameter of tens of meters. The functionality of the remote sensing system based on this radar meets the requirements for ice observation and navigation systems for seagoing ships off the coast. The simulation results confirm the promise of further research in this direction and can be used in the development of radar systems with synthesized antenna aperture mounted on rotating rotor blades.

scholarly journals Radar system with dedicated planar traveling wave antennas for elderly people monitoring

2020 ◽  
Vol 18 ◽  
pp. 97-110
Author(s):  
Sassan Schäfer ◽  
Simon Müller ◽  
Daniel Schmiech ◽  
Andreas R. Diewald
Keyword(s):  
Elderly People ◽  
Antenna Arrays ◽  
Traveling Wave ◽  
Radar System ◽  
Propagation Path ◽  
Design Parameters ◽  
Microstrip Technology ◽  
Actual Object ◽  
Radar Systems ◽  
24 Ghz

Abstract. Radar systems for contactless vital sign monitoring are well known and an actual object of research. These radar-based sensors could be used for monitoring of elderly people in their homes but also for detecting the activity of prisoners and to control electrical devices (light, audio, etc.) in smart living environments. Mostly these sensors are foreseen to be mounted on the ceiling in the middle of a room. In retirement homes the rooms are mostly rectangular and of standardized size. Furniture like beds and seating are found at the borders or the corners of the room. As the propagation path from the center of the room ceiling to the borders and corners of a room is 1.4 and 1.7 time longer the power reflected by people located there is 6 or even 10 dB lower than if located in the center of the room. Furthermore classical antennas in microstrip technology are strengthening radiation in broadside direction. Radar systems with only one single planar antenna must be mounted horizontally aligned when measuring in all directions. Thus an antenna pattern which is increasing radiation in the room corners and borders for compensation of free space loss is needed. In this contribution a specification of classical room sizes in retirement homes are given. A method for shaping the antenna gain in the E-plane by an one-dimensional series-fed traveling wave patch array and in the H-plane by an antenna feeding network for improvement of people detection in the room borders and corners is presented for a 24 GHz digital beamforming (DBF) radar system. The feeding network is a parallel-fed power divider for microstrip patch antennas at 24 GHz. Both approaches are explained in theory. The design parameters and the layout of the antennas are given. The simulation of the antenna arrays are executed with CST MWS. Simulations and measurements of the proposed antennas are compared to each other. Both antennas are used for the transmit and the receive channel either. The sensor topology of the radar system is explained. Furthermore the measurement results of the protoype are presented and discussed.

scholarly journals Probabilistic analysis of ambiguities in radar echo direction of arrival from meteors

2020 ◽  
Author(s):  
Daniel Kastinen ◽  
Johan Kero
Keyword(s):  
Bayesian Method ◽  
Direction Of Arrival ◽  
Radar System ◽  
Stable Region ◽  
Radar Signal ◽  
Ambient Atmosphere ◽  
Radar Systems ◽  
Mu Radar ◽  
Meteor Trail ◽  
The Antarctic

Abstract. Meteors and hard targets produce coherent radar echoes. If measured with an interferometric radar system, these echoes can be used to determine the position of the target through finding the Direction Of Arrival (DOA) of the incoming echo onto the radar. If the DOA of meteor trail plasma drifting with the ambient atmosphere is determined, the neutral wind at the observation altitude can be calculated. Specular meteor trail radars have become widespread scientific instruments to study atmospheric dynamics. Meteor head echo measurements also contribute to studies of the atmosphere as the meteoroid input of extraterrestrial material is relevant for a plethora of atmospheric phenomena. Depending on the spatial configuration of radar receiving antennas and their individual gain patterns, there may be an ambiguity problem when determining the DOA of an echo. Radars that are theoretically ambiguity free are known to still have ambiguities that depend on the total radar Signal to Noise Ratio (SNR). In this study we investigate robust methods which are easy to implement to determine the effect of ambiguities on any hard target DOA determination by interferometric radar systems. We apply these methods specifically to simulate four different radar systems measuring meteor head and trail echoes using the multiple signal classification (MUSIC) DOA determination algorithm. The four radar systems are the middle and upper atmosphere (MU) radar in Japan, a generic Jones 2.5λ specular meteor trail radar configuration, the Middle Atmosphere Alomar Radar System (MAARSY) radar in Norway and the The Program of the Antarctic Syowa Mesosphere Stratosphere Troposphere Incoherent Scatter (PANSY) radar in the Antarctic. We also examined a slightly perturbed Jones 2.5λ configuration used as a meteor trail echo receiver for the PANSY radar. All the results are derived from simulations and their purpose is to grant understanding of the behaviour of DOA determination. General results are: there may be a region of SNRs where ambiguities are relevant; Monte Carlo simulation determines this region and if it exists; the MUSIC function peak value is directly correlated with the ambiguous region; a Bayesian method is presented that may be able to analyse echoes from this region; the DOA of echoes with SNRs larger then this region are perfectly determined; the DOA of echoes with SNRs smaller then this region completely fail to be determined; the location of this region is shifted based on the total SNR versus the channel SNR in the direction of the target; asymmetric subgroups can cause ambiguities even for ambiguity free radars. For a DOA located at the zenith, the end of the ambiguous region is located at 17 dB SNR for the MU radar and 3 dB SNR for the PANSY radar. The Jones radars are usually used to measure specular trail echoes far from zenith. The ambiguous region for a DOA at 75.5° elevation and 0° azimuth ends at 12 dB SNR. Using the Bayesian method it may be possible to analyse echoes down to 4 dB SNR for the Jones configuration, given enough data points from the same target. The PANSY meteor trail echo receiver did not deviate significantly from the generic Jones configuration. The MAARSY radar could not resolve arbitrary DOAs sufficiently well to determine a stable region. However, if the DOA search is restricted to 70° elevation or above by assumption, stable DOA determination occurs above 15 dB SNR.

A female perspective: testing the effects of noise masking on signal transmission patterns inside the nest box

Behaviour ◽  
2019 ◽  
Vol 157 (1) ◽  
pp. 59-76 ◽  
Author(s):  
Erin E. Grabarczyk ◽  
Sharon A. Gill
Keyword(s):  
Cross Correlation ◽  
Signal Transmission ◽  
Measured Signal ◽  
Signal To Noise ◽  
House Wren ◽  
Noise Masking ◽  
Nest Boxes ◽  
Cavity Nesting ◽  
Song Transmission ◽  
Correlation Factors

Abstract During the breeding season, avian pairs coordinate interactions with songs and calls. For cavity nesting birds, females inside nest boxes may rely on male vocalizations for information. Anthropogenic noise masks male songs, which could affect information gained by females. We explored song transmission from a female house wren (Troglodytes aedon) perspective, testing the hypothesis that noise masking alters songs that reach females inside nest boxes. We broadcast songs at three distances up to 25 m from nest boxes and re-recorded songs using two microphones, positioned inside and outside nest boxes. We measured signal-to-noise ratios and cross-correlation factors to estimate the effects of masking on transmission. In noise, songs received inside nest boxes had lower signal-to-noise ratios and cross-correlation factors than songs recorded outside of boxes, and these effects decreased with distance. For females, noise may reduce information conveyed through male songs and in response pairs may need to adjust their interactions.

Netted Radar System Design with Spread Spectrum Technology

2011 ◽  
Vol 55-57 ◽  
pp. 648-653
Author(s):  
Lian Qing Fu ◽  
Li Sheng Yang ◽  
Tao Wang ◽  
Qing Le Zhang
Keyword(s):  
System Design ◽  
Spread Spectrum ◽  
Cross Correlation ◽  
Mutual Interference ◽  
Radar System ◽  
Power Ratio ◽  
Emission Signal ◽  
Simulation Results ◽  
Correlation Properties

In this paper, a novel netted radar system is designed to reduce the influence of mutual interference between signals. The emission signals of all stations are assigned the orthogonal PN codes. Because of the good autocorrelation and cross-correlation properties, mutual interference becomes weaker and signals from different stations could be separated by the preassigned PN codes. At the same time, the spectrum of the emission signal is spreaded, the peak-to-mean envelope power ratio (PMEPR) and the intercepted probability of the signals descend therefore. Simulation results show the good performance of the proposed approach.

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