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1

DOA Estimation of Ultrasonic Signal by Indirect Phase Shift Determination

Kreczmer Bogdan

Archives of Acoustics

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2024

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Vol. 49, nr 1

107--120

EN

The paper presents the concept of the method of determining the direction of ultrasonic signal arrival, i.e., the azimuth and elevation angles. This method is an extension of the previous approach which was proposed to determine only the azimuth angle. The approach is based on the indirect phase determination. This makes it possible to tolerate spacing of receivers greater than half the wavelength of the received signal. At the same time, it provides increased measurement accuracy and reduced hardware requirements. To check the robustness of the method, simulations were carried out for the geometric arrangement of the receivers of the sonar module, for which the method was then implemented. This sonar module was used in the conducted experiments. The results of these simulations and experiments are included in the paper and discussed.

2

Model systemu detekcji przeszkód i mapowania środowiska dla autonomicznych pojazdów podwodnych

Kot Rafał, Piskur Paweł, Sigiel Norbert

Pomiary Automatyka Robotyka

|

2023

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R. 27, nr 4

19--26

PL

W artykule przedstawiono model systemu detekcji przeszkód i mapowania środowiska, bazujący na przetwarzaniu obrazowym w czasie rzeczywistym, przeznaczony dla autonomicznego pojazdu podwodnego. Model został zrealizowany w oparciu o parametry pracy rzeczywistego sonaru z mechanicznym przestawianiem wiązki Tritech Micron Sonar. Działanie systemu detekcji zostało zweryfikowane z wykorzystaniem matematycznego modelu autonomicznego pojazdu podwodnego poruszającego się w środowisku podwodnym wyrażonym mapą testową przygotowaną na bazie rzeczywistych pomiarów zrealizowanych za pomocą ww. sonaru. Model systemu pozwala wykrywać i zapisywać w postaci mapy, przeszkody znajdujące się w polu widzenia sonaru w czasie rzeczywistym.

EN

This article presents a real-time model of an obstacle detection and environmental mapping system based on image processing for an autonomous underwater vehicle (AUV). The model was based on Tritech Micron Sonar operating parameters with mechanical beam adjustment. The operation of the detection system was verified using a mathematical model of an autonomous underwater vehicle moving in the underwater environment, expressed by a test map prepared based on actual measurements of the above-mentioned sonar. The system model allows for detecting and mapping obstacles in the sonar’s field of view in real-time.

3

Conditions for multiple acquisition of echoes from stationary targets in successive transmissions of active sonars

Kilian Lech, Schmidt Aleksander, Rudnicki Mariusz

Vibrations in Physical Systems

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2022

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Vol. 33, nr 3

art. no. 2022308

EN

In echolocation, the highest possible number of contacts with a detected target is clearly decisive on the possibilities of echo processing to optimise the estimation of distinctive characteristics of the observed target. In hydrolocation, the slow propagation of acoustic waves in water reduces the number of contacts of echosounders and sonars with detected targets. The article considers model conditions for acquiring multiple contacts with stationary targets detected by various sounding methods - with echosounders, classic active sonars and side looking sonars. Appropriate formulas explicitly linking the possible number of echo signals from the target in a specific geometry of the survey performed at the assumed speed are presented. These formulas are intuitively clear and not very complicated, but their value lies in the ability to instantly combine the vessel speed with the sounding effects, and may be a clear argument for imposing a low sounding speed, which make it difficult to steer the vessel.

4

An Efficient Edge Preserving Interpolation Method for Underwater Acoustic Image Resolution Enhancement

Priyadharsini R., Sree Sharmila T.

Archives of Acoustics

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2022

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Vol. 47, No. 2

267--274

EN

Underwater acoustic images are acquired using sonar instrument that uses sound propagation to navigate and map the sea floor. The sonar devices are effectively used to create images of large area of the seabed. However, the visual perception of the object in the acoustic image depends on refraction, which is a function of changes in the speed of sound in successive layers of water. And refraction depends mainly on temperature, slightly on salinity and hydrostatic pressure. The quality and resolution of sonar imaging of the bottom depends on many other factors such as pitch, yaw and heave of the side scan sonar, the presence of volume scatterers in the water body, the distance of the sonar from the bottom and orientation of the object. Generally, the objects in an acoustic image would be of small size compared to their normal size as the distance between the sonar and object is larger. To detect and recognize the objects in the images, the resolution should be enhanced. In this paper, we propose an efficient edge preserving interpolation method for underwater acoustic image resolution enhancement which preserves the edge sharpness. The method handles the diagonal pixels in the first pass, in turn fills the horizontal and vertical pixels in the second pass. The results obtained are compared with the state-of-the-art interpolation techniques and the performance measures such as Peak Signal to Noise Ratio (PSNR) and Structural Similarity Index Measurement (SSIM) shows an improved result.

5

Training RBF NN Using Sine-Cosine Algorithm for Sonar Target Classification

Wang Yixuan, Yuan LiPing, Khishe Mohammad, Moridi Alaveh, Mohammadzade Fallah

Archives of Acoustics

|

2020

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Vol. 45, No. 4

753--764

EN

Radial basis function neural networks (RBF NNs) are one of the most useful tools in the classification of the sonar targets. Despite many abilities of RBF NNs, low accuracy in classification, entrapment in local minima, and slow convergence rate are disadvantages of these networks. In order to overcome these issues, the sine-cosine algorithm (SCA) has been used to train RBF NNs in this work. To evaluate the designed classifier, two benchmark underwater sonar classification problems were used. Also, an experimental underwater target classification was developed to practically evaluate the merits of the RBF-based classifier in dealing with high-dimensional real world problems. In order to have a comprehensive evaluation, the classifier is compared with the gradient descent (GD), gravitational search algorithm (GSA), genetic algorithm (GA), and Kalman filter (KF) algorithms in terms of entrapment in local minima, the accuracy of the classification, and the convergence rate. The results show that the proposed classifier provides a better performance than other compared classifiers as it classifies the sonar datasets 2.72% better than the best benchmark classifier, on average.

6

Multi-Layer Perceptron Neural Network Utilizing Adaptive Best-Mass Gravitational Search Algorithm to Classify Sonar Dataset

Mosavi Mohammad Reza, Khishe Mohammad, Naseri Mohammad Jafar, Parvizi Gholam Reza, Ayat Mehdi

Archives of Acoustics

|

2019

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Vol. 44, No. 1

137--151

EN

In this paper, a new Multi-Layer Perceptron Neural Network (MLP NN) classifier is proposed for classifying sonar targets and non-targets from the acoustic backscattered signals. Besides the capabilities of MLP NNs, it uses Back Propagation (BP) and Gradient Descent (GD) for training; therefore, MLP NNs face with not only impertinent classification accuracy but also getting stuck in local minima as well as lowconvergence speed. To lift defections, this study uses Adaptive Best Mass Gravitational Search Algorithm (ABGSA) to train MLP NN. This algorithm develops marginal disadvantage of the GSA using the bestcollected masses within iterations and expediting exploitation phase. To test the proposed classifier, this algorithm along with the GSA, GD, GA, PSO and compound method (PSOGSA) via three datasets in various dimensions will be assessed. Assessed metrics include convergence speed, fail probability in local minimum and classification accuracy. Finally, as a practical application assumed network classifies sonar dataset. This dataset consists of the backscattered echoes from six different objects: four targets and two non-targets. Results indicate that the new classifier proposes better output in terms of aforementioned criteria than whole proposed benchmarks.

7

Estimation of the Azimuth Angle of the Arrival Direction for an Ultrasonic Signal by Using Indirect Determination of the Phase Shift

Kreczmer Bogdan

Archives of Acoustics

|

2019

|

Vol. 44, No. 3

585--601

EN

The paper presents and discusses a method of azimuth determination of ultrasonic echo arrival in air. The basis of the presented approach is the assumption that the received signal is a narrowband one. In this way, the direction of the signal arrival can be determined based on its phase shift using two receivers. When the distance between the receivers exceeds half of the wavelength of the received signal, a problem of ambiguity in determining the angle of arrival arises. To solve this, a method using multiple pairs of receivers was used. Its robustness and temperature dependence is analysed. The most import ant advantages of the presented approach are simplified computations and low hardware requirements. Experimental data made it possible to show that for strong echoes, the accuracy is higher than 0.5°. In the case of weak echos, it is reduced to about 2°. Because the method is based on phase shift measurement, the ultrasonic sonar that uses this method can be compact in size. Moreover, owing to the theoretical analysis, certain properties of the mutual location of the receivers were found and formally proved. They are crucial for determining proper receivers’ inter-distances.

8

Modeling of performance of a AUV vehicle towards limiting the hydro-acoustic field

Gerigk M. K.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2018

|

Vol. 12, no. 4

687--692

EN

Some results of research devoted to the modeling of a AUV-Stealth vehicle performance towards limiting its hydro-acoustic field are presented in the paper. At the beginning the AUV-Stealth autonomous underwater vehicle concept is described. Then the method of research is introduced. Next the key design drivers of the AUV-Stealth vehicle are presented. Between them are the AUV-Stealth hull form, arrangement of internal spaces, materials, hull covers, energy supply and propulsion system, etc. Some results of the hydrodynamic and stealth characteristics of the AUV-Stealth vehicle are briefly described. It is presented in the paper that the hull form, construction materials including the covers may affect the AUV-Stealth vehicle boundary layer and wake. This may create some problems of identification of the AUV-Stealth vehicle using a sonar or hydrophone. The final conclusions are presented.

9

Identification of sonar detection signal based on fractional Fourier transform

Wang B., Tang J., Yu F., Zhu Z.

Polish Maritime Research

|

2018

|

S 2

125--131

EN

Aiming at the source of underwater acoustic emission, in order to identify the enemy emission sonar source accurately. Using the digital watermarking technology and combining with the good time-frequency characteristics of fractional Fourier transform (FRFT),this paper proposes a sonar watermarking method based on fractional Fourier transform. The digital watermark embedding in the fractional Fourier transform domain and combined with the coefficient properties of the sonar signal in the fractional Fourier transform to select the appropriate watermark position. Using the different characteristics of the signals before and after embedding, an adaptive threshold was set for the watermark detection to realize the discrimination of sonar signals. The simulation results show the feasibility and has better resolution and large watermark capacity of this method, while the robustness of the watermark is better, and the detection precision is further improved.

10

Indoor Mapping Using Sonar Sensor and Otsu Method

Dimitrova-Grekow T., Salauyou V., Kowalski K.

Measurement Automation Monitoring

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2017

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Vol. 63, No. 6

214--216

EN

In this paper we present an indoor mapping algorithm based on sonar sensor. The overall object detection and mapping experiment is based on small scale local spatial information which has been accomplished in a 2D geometrical map. Considering all drawbacks and pluses of ultrasonic sensors, we present an innovative mapping approach, applying the Otsu’s method and Hit-or-Miss for sonar-data processing. The collected data are treated as a gray-scale picture. For its binarization, we applied the well-known for vision-based systems threshold calculation. Then also the morphology effect, what rises additionally the mapping accuracy, as is shown at the end of the paper. The robot is based on the education construction set LEGO Mindstorms EV3 intelligent brick on ev3dev - a Debian Linux-based operating system and Python 2.0 have been used for programming. The results are evaluated and compared with the real space.

11

Azimuth angle determination for the arrival direction for an ultrasonic echo signal

Kreczmer B.

Journal of Automation Mobile Robotics and Intelligent Systems

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2017

|

Vol. 11, No. 2

31--41

EN

In the paper, an idea of a method of signal arrival direction estimation is presented. The influence of time error measurements on the usage of the method is described. An approach to the problem of an increase in the robustness of the method is proposed. The results of experiments are presented and discussed.

12

Mutual Clutter Suppression Techniques for FM Sonars

Marszal J., Rudnicki M., Jedel A., Salamon R., Kochańska I.

Archives of Acoustics

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2016

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Vol. 41, No. 4

721--729

EN

The article presents methods that help in the elimination of mutual clutter as well as the consequences of two FM sounding signal sonars operating in the same body of water and frequency band. An in-depth analysis of mutual clutter was carried out. The effects of sounding signal differentiation were determined, as was the Doppler effect on mutual clutter suppression. One of the methods analysed is of particular interest in a situation in which collaborating sonars are operating in opposite frequency modulation directions. This method is effective for both linear and hyperbolic frequency modulations. A formula was derived, identifying exactly how much quantities of clutter may be lessened. The work included comprehensive computer simulations and measurements as well as tests in real-life conditions.

13

Sonar surveys under challenging conditions in gas at very low pressure and in crude oil

Hasselkus F., Reitze A.

Przegląd Solny

|

2015

|

T. 11

109--115

EN

Sonar surveys have for decades been the established technique for the regular monitoring of gas and oil storage caverns. So as to have the best possible basic physical conditions gas caverns should be under the highest possible pressure at the time they are surveyed. This is all the more important the greater the distances to be measured. With regard to caverns located deeper than 1000 m pressures > 150 bar provide a good basis for achieving qualitatively reliable and focused measurements. Surveying shallow caverns with a low maximum pressure < 100 bar or caverns that for operational reasons have to be under low pressure is considerably more challenging than a “standard survey” under high pressure. The lower the pressure the higher the attenuation of the acoustic waves. Consequently to be able to interpret these reflections the measuring system must be in a position to amplify the significantly attenuated signal reflections by a suitable amplifier technology and by applying mathematical correlation techniques. Furthermore special transducer technology is necessary when working at such low pressures. Surveys in caverns at pressures between 80 and 90 bar had been carried out successfully for years. Then the task of surveying gas caverns with a pressure of just 45 bars presented a new challenge. Indeed, to obtain qualitatively usable results under these demanding basic conditions it was essential to have sophisticated transducer technology as well as high performance transmitter and receiver equipment. By carrying out special developments and modifications in this area equipment has been designed which enables distances of more than 85 m to be measured even if the pressure is as low as 45 bar. This provides the customer with a means of monitoring all parts of those caverns which previously were internally regarded as “unsurveyable” without having to flood the cavern with brine. The technical changes that have been made not only bring about advantages in terms of measuring greater distances at low pressure, but also provide extra performance. In caverns with an extremely long extension (e.g. elongated fingers due to leached potash zones, steeply inclined bedding and so on) it is now possible to measure considerably longer distances. In some cases it is even possible to measure distances of well over 100 m in gas or crude oil.

14

Digital signal processing applied to the modernization of Polish Navy sonars

Marszal J.

Polish Maritime Research

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2014

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nr 2

65--75

EN

The article presents the equipment and digital signal processing methods used for modernizing the Polish Navy’s sonars. With the rapid advancement of electronic technologies and digital signal processing methods, electronic systems, including sonars, become obsolete very quickly. In the late 1990s a team of researchers of the Department of Marine Electronics Systems, Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, began work on modernizing existing sonar systems for the Polish Navy. As part of the effort, a methodology of sonar modernization was implemented involving a complete replacement of existing electronic components with newly designed ones by using bespoke systems and methods of digital signal processing. Large and expensive systems of ultrasound transducers and their dipping and stabilisation systems underwent necessary repairs but were otherwise left unchanged. As a result, between 2001 and 2014 the Gdansk University of Technology helped to modernize 30 sonars of different types.

15

Dolphin-Inspired Target Detection for Sonar and Radar

Leighton T., White P.

Archives of Acoustics

|

2014

|

Vol. 39, No. 3

319--332

EN

Gas bubbles in the ocean are produced by breaking waves, rainfall, methane seeps, exsolution, and a range of biological processes including decomposition, photosynthesis, respiration and digestion. However one biological process that produces particularly dense clouds of large bubbles, is bubble netting. This is practiced by several species of cetacean. Given their propensity to use acoustics, and the powerful acoustical attenuation and scattering that bubbles can cause, the relationship between sound and bubble nets is intriguing. It has been postulated that humpback whales produce ‘walls of sound’ at audio frequencies in their bubble nets, trapping prey. Dolphins, on the other hand, use high frequency acoustics for echolocation. This begs the question of whether, in producing bubble nets, they are generating echolocation clutter that potentially helps prey avoid detection (as their bubble nets would do with man-made sonar), or whether they have developed sonar techniques to detect prey within such bubble nets and distinguish it from clutter. Possible sonar schemes that could detect targets in bubble clouds are proposed, and shown to work both in the laboratory and at sea. Following this, similar radar schemes are proposed for the detection of buried explosives and catastrophe victims, and successful laboratory tests are undertaken.

16

Integracja hydroakustycznych i magnetometrycznych metod w procesie pozyskiwania geodanych hydrograficznych

Stateczny A.

Roczniki Geomatyki

|

2013

|

T. 11, z. 1(58)

97--104

PL

Celem naukowym planowanych badań jest rozwinięcie metod przetwarzania hydrograficznych geodanych pomiarowych poszerzone o geodane magnetometryczne. Planowane badania obejmą cały kompleks metod procesu integracji hydrograficznych geodanych pomiarowych – danych batymetrycznych, sonarowych i magnetometrycznych. Łączne analizowanie danych pozyskanych różnymi sensorami umożliwi uzyskanie efektu synergicznego w tym szczególnie w procesie identyfikacji obiektów dennych i zalegających pod dnem akwenu. Wyniki badań wdrożone zostaną do praktyki hydrograficznej oraz w procesie budowy elektronicznych map nawigacyjnych, w tym między innymi elektronicznych map nawigacyjnych dla żeglugi śródlądowej, elektronicznych map podwodnych akwenów portowych i map batymetrycznych.

EN

In this paper, the problem of integration of hydrographical geodata obtained by various sensors is discussed. The planned works include the entire complex of geodata: bathymetric, sonar and magnetometric. Joint analyzing them will enable to get the synergetic effect, in particular in the process of identification of objects lying on the bottom and under the bottom of the basin. The results will be implemented in the hydrographical practice and in the process of producing electronic navigational charts, among others of inland water charts, port electronic maps and bathymetric maps.

17

Analiza wybranych metod poprawiania treści obrazów sonarowych

Łubczonek J., Zaniewicz G.

Roczniki Geomatyki

|

2013

|

T. 11, z. 2(59)

59--68

PL

Opracowanie obrazów sonarowych, podobnie jak lotniczych czy satelitarnych, wymaga przeprowadzenia złożonego procesu obróbki danych. Związane jest to zarówno z korekcją geometryczną jak również poprawianiem wartości zapisanych w pojedynczych pikselach. Zastosowanie danych sonarowych związane jest głównie z analizą informacji obrazowej. Stanowią one cenne źródło informacji o obiektach znajdujących się na dnie akwenu oraz jego ukształtowaniu. Obecne sensory sonarowe umożliwiają zapisanie danych w rozdzielczości wynoszącej kilka centymetrów, co teoretycznie powinno wpłynąć na poprawę potencjału interpretacyjnego obrazów. W istocie, mniejszy wymiar komórki rastra zwiększa szczegółowość obrazu, ale rejestracja jednokanałowa zmniejsza efektywność wykrycia i późniejszej identyfikacji obiektów. W związku z tym ważnym elementem w procesie interpretacji informacji sonarowej jest poprawianie jakości jego treści. Można to zrealizować za pomocą dedykowanych funkcji, które również stosuje się do poprawiania jakości zdjęć lotniczych czy obrazów satelitarnych. Obecne oprogramowanie daje szerokie możliwości poprawiania obrazów. Można tu wymienić programy dedykowane do obróbki cyfrowych fotografii, oprogramowanie GIS czy dedykowane programy do obróbki danych fotogrametryczno – teledetekcyjnych. Programy te są zazwyczaj zróżnicowane w zakresie funkcjonalności i dostępnych narzędzi. Ich obecne możliwości stały się motywacją do przeprowadzenia analizy wybranych metod poprawiania treści obrazów sonarowych. W niniejszej pracy analizę ukierunkowano na wyłonienie metod, które zwiększają efektywność wykrycia oraz późniejszej identyfikacji obiektów. W badaniach uwzględniono dedykowane oprogramowanie do obróbki danych sonarowych oraz stosowane w opracowaniu innych danych obrazowych. Praca realizowana w ramach projektu rozwojowego finansowany ze środków na naukę w latach 2011-2012 „Rozwinięcie metod przetwarzania geodanych w pomiarach hydrograficznych na akwenach morskich i śródlądowych”.

EN

Working with side scan sonar images is similar to aerial photographs or satellite images and it requires a complex process of data processing. This is due to the geometric correction and values correction stored in the individual pixels. The use of sonar data is mainly related to the analysis of visual information. They are a valuable source of information about objects on the sea bottom and their shape. The present sonar sensors allow the operator to record data at a resolution of a few centimetres, which in theory should improve potential interpretation of images. In fact, a smaller raster cell size increases the detail, but single-channel recording reduces the effectiveness of detection and later identification of objects. Therefore, an important element in the interpretation of the sonar information is to improve the quality of its content. This can be done by dedicated functions, which are also used to enhance the quality of aerial photographs or satellite images. The present software provides wide possibilities to correct images, including software dedicated to processing digital photos, GIS software or software dedicated for photogrammetry and remote sensing data processing. These programs are usually different in terms of functionality and tools available. Their present capabilities provide motivation to analyse selected methods to improve the content of sonar images. In this paper, analyses were directed at the identification of methods to increase the efficiency of detection and later identification of objects. In the studies, dedicated software for sonar data processing and software used in processing other imaging data were included. Research work is financed from the fund for science in years 2011 – 2012.

18

A novel method for archiving multibeam sonar data with emphasis on efficient record size reduction and storage

Moszynski M., Chybicki A., Kulawiak M., Lubniewski Z.

Polish Maritime Research

|

2013

|

nr 1

77--86

EN

Over the past few years considerable advances in sonar technology, spatial positioning capabilities and computer processing power have lead to significant improvements in mapping, imaging and technologies of seafloor exploration. Recently, modern multibeam echosounder systems (MBES) capable of recording backscatter data for the whole water column, not just for the seabed, have become available thus providing data allowing for visualization and analysis of objects other than the seabed such as single fish, fish schools or pollution. Unlike bathymetric sonars, which only capture the seafloor, multibeam systems produce very large amounts of data during surveys. Because of this, storing the data collected during hydrographic or scientific cruises becomes a crucial problem. In this context, the paper proposes a new approach for efficient reduction and storage of MBES records. The results of a sample implementation of the algorithm being tested on several different sets of MBES data are also discussed.

19

The influence of drive unit on measurement error of ultrasonic sensor in multi - rotor flying robot

Gardecki S., Gośliński J., Giernacki W.

Journal of Automation Mobile Robotics and Intelligent Systems

|

2013

|

Vol. 7, No. 2

12--17

EN

The article describes the impact of the drive units on the data obtained from ultrasonic sensors. These sensors are mounted on the multi-rotor flying robot. In experiments, previously designed ultrasonic sensor was used. On purpose of this study special testbed, consisted of a dynamometer and manipulator from KUKA company was created. In the research the influence of the location of the drive unit on the aforementioned sensor was measured. For this purpose, the sensor was placed in front, behind and in the line of the rotating propeller. The obtained results allowed to identify places where there are the least interference from the drive units that affect the ultrasonic sensor. Thanks to this, the results of measurements of the obstacles distance from a flying robot were improved.

20

Test results of bathymetric data processing obtained by swath sounder GS+

Stateczny A., Włodarczyk-Sielicka M.

Zeszyty Naukowe Akademii Marynarki Wojennej

|

2012

|

R. 53 nr 4 (191)

105-118

EN

A navigational chart is the primary source of information for the navigator. The main component that contributes significantly to the safety of navigation is the information on the depth of the area. A sonar, which uses acoustic waves is a device for bathymetric measurements and it measures the vertical distance between the head and the bottom or an object located at the bottom. For the purposes of the article, data was used from an interferometric sonar, which is a modification of a multi-beam sonar. Due to the very wide operating angle, it allows for simultaneous vertical data collection, similar to a typical multi-beam sonar, as well as horizontal data collection, much like a sidescan sonar. Bathymetric data is obtained not only on the basis of measurement of time, in which the acoustic wave reflected from the object returns to the receiving transducer, but also by measuring the difference between phases of the wave reaching the piezoelectric elements within a head. The paper presents the test result of bathymetric data processing obtained by the swath sonar GeoSwath+, which is trademark of GeoAcoustics. Data collected during the acquisition was subjected to filtration. For the purpose of the article, the authors used pre-filtered measurement data collected in the area of the Port of Szczecin. However, the filtered samples are large sets of data. Data reduction is a procedure meant to reduce the size of a data set to make it easier and more effective to analyze. This paper examines the capabilities of the GS+ software in the scope of reduced bathymetric data after filtration. The results of different settings are presented in the form of grids, which were then exported to the Surfer 10 software and subjected to detailed analysis.

PL

Mapa nawigacyjna jest głównym źródłem informacji dla nawigatora. Zasadniczym elementem, który wpływa na bezpieczeństwo nawigacji, jest informacja odnosząca się do głębokości morza. Urządzeniem do pomiarów batymetrycznych jest sonar. Mierzy pionową odległość pomiędzy przetwornikiem a dnem lub obiektem umieszczonym na dnie. Dla celów tego artykułu wykorzystano dane z sonaru interferometrycznego, który jest modyfikacją sonaru wielowiązkowego. Dzięki szerokiemu kątowi operacyjnemu pozwala on na symultaniczne zbieranie danych pionowych, podobnie jak typowy wielowiązkowy sonar, oraz danych poziomych, podobnie jak sonar boczny. Dane batymetryczne są uzyskiwane nie tylko na podstawie pomiaru czasu, lecz także poprzez mierzenie różnic fazowych pomiędzy elementami piezoelektrycznymi w przetworniku. Artykuł prezentuje przetwarzanie testowych danych batymetrycznych uzyskanych przez sonar GeoSwath+. Autorzy wykorzystali uprzednio przefiltrowane dane pomiarowe zebrane w rejonie Portu Szczecin. Ponieważ przefiltrowane próbki są dużymi zbiorami danych, poddano je redukcji, czyli procedurze zmniejszenia wielkości zbioru danych, aby łatwiej i efektywniej je analizować. Niniejszy artykuł bada możliwości sondy GS+ w zakresie zredukowanych danych batymetrycznych po filtracji. Wyniki różnych zestawień zostały zaprezentowane w formie siatek, które następnie eksportowano do programu Surfer 10 i poddawano szczegółowej analizie.