Estimating the delay-Doppler of target echo in a high clutter underwater environment using wideband linear chirp signals: Evaluation of performance with experimental data

2017 ◽  
Vol 142 (4) ◽  
pp. 2047-2057 ◽  
Author(s):  
Ge Yu ◽  
T. C. Yang ◽  
Shengchun Piao
Keyword(s):  
Experimental Data ◽  
Evaluation Of Performance ◽  
Underwater Environment ◽  
Chirp Signals ◽  
Linear Chirp

scholarly journals Pulse compression of linear chirp signals using a quadrature detector

2011 ◽  
Vol 32 (6) ◽  
pp. 261-263 ◽  
Author(s):  
Nur Mariah Khairah binti Abdul Aziz ◽  
Hirokazu Kurabayashi ◽  
Naohiko Tanaka
Keyword(s):  
Pulse Compression ◽  
Chirp Signals ◽  
Linear Chirp

scholarly journals VERSATILE CHIRP SINE GENERATOR ON FIXED-POINT FPGA

2020 ◽  
Vol 60 (6) ◽  
Author(s):  
Jan Kunz ◽  
Petr Beneš
Keyword(s):  
Fixed Point ◽  
Phase Difference ◽  
Signal Generation ◽  
Vibration Testing ◽  
Chirp Signals ◽  
Linear Chirp ◽  
Pros And Cons ◽  
Sine Signal ◽  
Hardware Platforms ◽  
Point Arithmetic

This paper deals with a logarithmic and a linear chirp sine generation on a fixed-point FPGA mainly for vibration testing, nevertheless, the generator can also be used in other areas. A basic overview of the logarithmic chirp sine signal is provided. Then, methods of software signal generation as well as different hardware platforms are briefly described and their pros and cons are mentioned. A DDS generator on FPGA needs the phase difference between samples as an input. This generation for the logarithm chirp sine signal is presented, and its resolution, errors and limitations on fixed-point arithmetic are revealed. Our implementation runs on Compact RIO 9067, uses 32-bit fixed-point and is able to generate linear and logarithm chirp signals from 10 Hz to 7 kHz with a minimum chirp speed of 1 oct/min.

Statistically efficient simultaneous amplitude measurement of multiple linear chirp signals

2021 ◽  
pp. 1-1
Author(s):  
Antonio Moschitta ◽  
Antonella Comuniello ◽  
Francesco Santoni ◽  
Alessio De Angelis ◽  
Paolo Carbone ◽  
...  
Keyword(s):  
Amplitude Measurement ◽  
Chirp Signals ◽  
Linear Chirp

scholarly journals Analysis of the accuracy of building 3D coordinates of the underwater robot workspace

2020 ◽  
pp. 163-170
Author(s):  
B.A. Skorohod ◽  
◽  
P.V. Zhiyakov ◽  
A.V. Statsenko ◽  
S.I. Fateev ◽  
...  
Keyword(s):  
Experimental Data ◽  
Image Processing ◽  
Underwater Robot ◽  
Random Component ◽  
Underwater Environment ◽  
Camera Image ◽  
Image Processing Algorithms ◽  
Processing Algorithms ◽  
Underwater Camera ◽  
The Impact

Distortion of underwater images can impair both the accuracy and robustness of 3D scene reconstruction algorithms. The problems that arise are related to the lack of robustness of these methods to changes in the underwater environment and features of transmitting and receiving signals under water, including, in particular, uneven illumination of the underwater environment, rapid attenuation, scattering and refraction of light when passing through an inhomogeneous medium of air-water-glass, limiting the frequency spectrum of passing light, which leads to the absorption of low-frequency components to a greater extent than light of higher frequencies. All this seriously complicates the ability to extract information about the scene as a whole and objects of interest located in the underwater environment, limits the use of standard image processing algorithms and requires their significant improvement. This article offers a new approach to analyzing the accuracy of constructing 3D coordinates of the working space of an underwater robot. The approach is based on underwater camera calibration, assessment of camera image centers taking into account the waterproof shell. We use statistical analysis that allows us to evaluate the impact of all sources of disturbances (both hardware and software) based only on experimental data. In particular, it shows how to get the error distribution using the measured values of the calibration sample and obtained by triangulation under underwater conditions. This makes it possible to simultaneously evaluate the systematic error and the distribution characteristics of the random component of the error in restoring 3D coordinates of the workspace. An important feature of the proposed approach is the ability to assess the impact of all sources of disturbances in the aggregate, including the design of a waterproof shell, based only on experimental data obtained in the underwater environment. In addition, the same approach can also provide estimates of the position of camera image centers, allowing for the presence of a waterproof shell to improve the accuracy of image processing algorithms. The proposed approach was tested on real data.

scholarly journals Features of backscatter ionospheric sounding as studied with a chirp ionosonde

2017 ◽  
Vol 3 (3) ◽  
pp. 54-60 ◽  
Author(s):  
Сергей Пономарчук ◽  
Sergey Ponomarchuk ◽  
Владимир Куркин ◽  
Vladimir Kurkin ◽  
Максим Пензин ◽  
...  
Keyword(s):  
Experimental Data ◽  
Signal Propagation ◽  
Time Of Day ◽  
Propagation Mode ◽  
Chirp Signals ◽  
Different Seasons ◽  
Ionospheric Sounding

We present the results of the studies of backscatter ionospheric sounding (BS) on the basis of a multipurpose chirp ionosonde developed in ISTP SB RAS. We analyze BS experimental data obtained during different seasons from 2005 to 2009. The accumulated dataset allows us to investigate features of BS signal propagation in various heliogeophysical conditions. To analyze and interpret BS signals on ionograms, we use the results of modeling of characteristics for chirp signals in the backscatter and oblique ionospheric sounding under a waveguide approach. We have revealed the most characteristic types of ionograms and have established conditions of appearance of a given type depending on the time of day, season, sounding direction, and medium conditions. In winter, spring, and autumn, the prevailing types of ionograms are those with BS signals corresponding to the propagation mode through reflection from the F layer. Signals reflected by E or Es layers are recorded during summer periods. At the same time, frequencies of the received signals are sufficiently large, and sometimes there are no reflections from the F layer.

Effect of noise, partial synchronization, and sampling frequency inaccuracies on amplitude measurement of multiple Linear Chirp signals

Measurement ◽  
2021 ◽  
pp. 109635
Author(s):  
Antonio Moschitta ◽  
Antonella Comuniello ◽  
Alessio De Angelis ◽  
Francesco Santoni ◽  
Paolo Carbone
Keyword(s):  
Sampling Frequency ◽  
Partial Synchronization ◽  
Amplitude Measurement ◽  
Chirp Signals ◽  
Linear Chirp

scholarly journals Features of backscatter ionospheric sounding as studied with a chirp ionosonde

2017 ◽  
Vol 3 (3) ◽  
pp. 61-69 ◽  
Author(s):  
Сергей Пономарчук ◽  
Sergey Ponomarchuk ◽  
Владимир Куркин ◽  
Vladimir Kurkin ◽  
Максим Пензин ◽  
...  
Keyword(s):  
Experimental Data ◽  
Signal Propagation ◽  
Time Of Day ◽  
Propagation Mode ◽  
Chirp Signals ◽  
Different Seasons ◽  
Ionospheric Sounding

We present the results of studies of backscatter ionospheric sounding (BS) on the basis of a multipurpose chirp ionosonde developed in ISTP SB RAS. We analyze BS experimental data obtained during different seasons from 2005 to 2009. The accumulated dataset allows us to investigate features of BS signal propagation in various heliogeophysical conditions. To analyze and interpret BS signals on ionograms, we use the results of modeling of characteristics for chirp signals in the backscatter and oblique ionospheric sounding under the waveguide approach. We have revealed the most characteristic types of ionograms and have established conditions of appearance of a given type depending on the time of day, season, sounding direction, and medium conditions. In winter, spring, and autumn, the prevailing types of ionograms are those with BS signals corresponding to the propagation mode through reflection from the F layer. Signals reflected by E or Es layers are recorded during summer periods. At the same time, frequencies of the received signals are sufficiently large, and sometimes there are no reflections from the F layer.

Sign in / Sign up

Export Citation Format

Share Document