scholarly journals SwathDop: Multibeam Pulse-Coherent Doppler Sonar for Scanning 2D Velocity Sections near the Sediment–Water Interface

2019 ◽  
Vol 36 (11) ◽  
pp. 2153-2169
Author(s):  
Mahdi Razaz ◽  
Len Zedel ◽  
Alex E. Hay
Keyword(s):  
Sediment Transport ◽  
Software Defined Radio ◽  
Wide Band ◽  
Preliminary Test ◽  
Unidirectional Flow ◽  
Sonar System ◽  
Median Diameter ◽  
Independent Observations ◽  
Signal Processing Algorithms ◽  
Doppler Sonar

AbstractThis paper considers the problem of accurately measuring the sediment transport over bedforms where flow evolves continuously both in time and space. For this purpose, we have developed a pulse-to-pulse coherent Doppler sonar system designed in bistatic geometry with two fan-beam transmitters symmetrically positioned on each side of a multielement receive array. The system resolves 2D velocity components within a ±20° (~0.5 m by ~0.5 m) swath. The software-defined radio data acquisition and control system limited us at present to eight independent receiver channels, and consequently the azimuthal resolution of the system is 4°. As a preliminary test of the sonar system, the system operation was simulated using a model developed to predict coherent sonar performance. The uncertainties with respect to the prescribed values and mean measurements in the model results were confined to 0.35 and 0.23 cm s−1, respectively, in the presence of strong shear (~150 s−1) and 50 cm s−1 horizontal flow. An important thing is that the model allowed us to test and develop the signal processing algorithms necessary to invert the multibeam sonar data. Using sand of 0.4-mm median diameter, the laboratory trials were carried out in active sediment transport conditions over dunes with 2-m wavelength and ~0.90 m s−1 unidirectional flow velocities. The results presented here focus mainly on 2D velocity field and indicate an average 4% deviation from the wake law and 8% from independent observations made with the wide-band multifrequency coherent Doppler profiler (MFDop) instrument under similar flow conditions.

Performance Evaluation of SDR Blade RF using Wide-band Monopole Antenna for Spectrum Sensing Applications

2021 ◽  
Vol 36 (4) ◽  
pp. 419-424
Author(s):  
Ahmed Ibrahim ◽  
Wael Ali ◽  
Hassan Aboushady
Keyword(s):  
Performance Evaluation ◽  
Cognitive Radio ◽  
Spectrum Sensing ◽  
Software Defined Radio ◽  
Ground Plane ◽  
Wide Band ◽  
Monopole Antenna ◽  
Antenna Design ◽  
Wireless Technologies ◽  
Sensing Applications

A spectrum-sensing algorithm is used to detect the available and the occupied frequency bands. The wideband antenna design approach is used for a microstrip fed monopole antenna that can be used for various wireless technologies such as GSM, UMTS, LTE, and WiFi operating at different frequencies from 1.25 to 3 GHz. The antenna is constructed from two copper layers of rectangular radiator and a partial ground plane. These layers are printed on an RO4003 substrate with dimensions 60 x 80 mm2. The antenna is experimentally fabricated to verify the simulation predictions and good matching between simulated and measured results is achieved. The wide-band antenna is tested by connecting it to the receiver of the Blade-RF Software Defined Radio (SDR) platform. A matlab script is then used to control the SDR board and to perform Spectrum Sensing for Cognitive Radio Applications.

scholarly journals Sediment dynamics on a steep, megatidal, mixed sand-gravel-cobble beach

2014 ◽  
Vol 2 (1) ◽  
pp. 117-152 ◽  
Author(s):  
A. E. Hay ◽  
L. Zedel ◽  
N. Stark
Keyword(s):  
Wide Band ◽  
Sediment Dynamics ◽  
Coarse Grained ◽  
Bay Of Fundy ◽  
Wave Forcing ◽  
Structure Of Flow ◽  
Median Diameter ◽  
Field Deployment ◽  
Bed Material ◽  
Cobble Beach

Abstract. Results are presented from a pilot study of shoreface sediment dynamics on a steep, poorly sorted, coarse-grained, mega-tidal beach at the head of the Bay of Fundy, Nova Scotia, Canada. The experiment involved the first field deployment of a prototype wide- band, pulse-coherent, bistatic acoustic Doppler profiling system. Measurements of the vertical structure of flow and turbulence above a sloping bed, as well as bed material velocity, demonstrate the capabilities of this instrument vis-a-vis studies of nearshore sediment dynamics at the field scale. The second focus of the paper is the surprising observation that the surficial sediment median diameter, across the lower two-thirds of the intertidal zone, underwent a pronounced decrease when wave forcing was more energetic, compared to values observed during calmer conditions. The explanation for this result appears to involve the formation – in wave-dominated conditions – of O(1 m)-wavelength, 20 cm high ripples on the rising tide, which are then planed flat by the swash and/or the shorebreak on the subsequent ebb.

scholarly journals Design of a Low-Cost Ultra-Wide-Band Radar Platform

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2867
Author(s):  
Marko Malajner ◽  
Danijel Šipoš ◽  
Dušan Gleich
Keyword(s):  
Power Supply ◽  
Software Defined Radio ◽  
Pulse Generator ◽  
Low Cost ◽  
Wide Band ◽  
Negative Power ◽  
Analog To Digital ◽  
Sample Rate ◽  
Improved Design ◽  
Strobe Pulse

This paper proposes an improved design of a pulse-based radar. An improved design of a pulse generator is presented using step recovery diodes and a signal mixer for the received signal. Two-step recovery diodes produce pulses of 120 ps in duration. A pulse generator is improved by removing the negative power supply, resulting in a reduced number of electronic pulses. A sampling mixer at the receiver’s site receives the generated signal and stretches it from picoseconds into microseconds. The improved pulse generator is also used in the sampling mixer as a strobe pulse generator, which makes the sampling mixer much simpler. The stretched signal is then sampled by a low sample rate using an analog to digital converter. The proposed radar design achieves up to 8 GHz bandwidth and an equivalent receiving sample rate of about 100 GSa/s. The radar is controlled using a software-defined radio called Red Pitaya, which is also used for data acquisition. The proposed radar design uses widely available commercial components, which makes radar design widely available with low cost implementation.

Field trial of a Doppler sonar system for fisheries applications

2003 ◽  
Vol 114 (4) ◽  
pp. 2375-2375
Author(s):  
Cristina D. S. Tollefsen ◽  
Len Zedel
Keyword(s):  
Field Trial ◽  
Sonar System ◽  
Doppler Sonar

scholarly journals Designing a Real-time Swept Spectrum Analyser with USRP B210

2021 ◽  
Vol 5 (2) ◽  
pp. 329-339
Author(s):  
N. Bello ◽  
K.O. Ogbeide
Keyword(s):  
Cognitive Radio ◽  
Real Time ◽  
Spectrum Sensing ◽  
Software Defined Radio ◽  
Wide Band ◽  
Energy Detection ◽  
Promising Technique ◽  
Basic Functions ◽  
High Flexibility ◽  
Very High

Cognitive radio has received considerable amount of attention as a promising technique to provide dynamic spectrum allocation. Spectrum sensing is one of the basic functions in the cognitive radio and is crucial to all other functions. Software- defined radios (SDRs) are considered due to its very high flexibility and have become a common platform for CR implementation replacing expensive spectrum analysers. The most popular among various SDR platforms is the universal software-defined radio peripheral (USRP). This paper presents a real-time swept spectrum sensing solution based on USRP B210. It also presents a detailed explanation of the concept of energy detection and the methodology for wide-band sensing. Finally, the performance of the proposed sensing solution is analysed through FFT graphs and spectrogram plot taken for 8 hours. The results showed that the proposed sensing solution was capable of achieving high resolution in the frequency domain of the wide band measured which implies that wide bands with heterogenous signals like the ISM band can be accurately resolved and analysed.

Doppler Sonar System

1964 ◽  
Vol BME-11 (1 & 2) ◽  
pp. 53-53
Author(s):  
R. Stuart MacKay
Keyword(s):  
Sonar System ◽  
Doppler Sonar

Cognitive Radio Network-Based Design and Security Challenges in 5G Communication

2020 ◽  
pp. 221-241 ◽  
Author(s):  
Arvind Dhaka ◽  
Amita Nandal ◽  
Rahul Dixit
Keyword(s):  
Cloud Computing ◽  
Cognitive Radio ◽  
Mobile Networks ◽  
Software Defined Radio ◽  
General Purpose ◽  
Security Issues ◽  
Computing Platform ◽  
Security Challenges ◽  
Signal Processing Algorithms ◽  
Computing Platforms

This chapter deals with the main development challenges of 5G network. The 5G terminals can be made as reconfigurable multimode and cognitive radio enabled. Such networks will have software defined radio modulation schemes. The 5G mobile networks will focus on the development of the user terminals where the terminals will have access to different wireless technologies at the same time and will combine different flows from different technologies. It is beneficial to deploy cloud-computing platforms running on general-purpose hardware, leading to a cloud-RAN system. This chapter is focused on the challenges and benefits of implementing reconfigurable signal processing algorithms on a cloud-computing platform and address various security issues with cognitive radio networks.

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