FMCW SAR THESIS

A flight test campaign has been organized during the last part of A signal processing procedure with system calibration methods to mitigate the effects of deramp, phase noise and nonlinearity of the VCO on the beat spectrum is proposed. Again, proper processing methods to overcome such limitation due to frequency non-linearities were not available to the scientific community. The results were very successful. Within the framework of the project, the following novelties and main results have been reached and are presented in the thesis: However, the practical feasibility of an airborne FMCW SAR was not evident; the experimental sensors described in literature were, in fact, radars mounted on rail supports operating in ground SAR configurations and at short distances. The reconstructed images show the improvement of image quality and accuracy in the target position.

One of the limiting factors of FMCW radars is that the ramp signal modulates the received signal, which limits the minimum achievable range resolution. This work seeks to overcome the three design issues mentioned above through the development of simulation platforms, which has been shown to be well-suited for the comprehensive study of these effects. Electrical Engineering, Mathematics and Computer Science. For airborne FMCW radars, however, the stop-and-go approximation can be not valid anymore because the platform is actually moving while continuously transmitting. Finally, several avenues of further study and applications are suggested.

They consume little power and, due to the fact that they are continuously operating, they can transmit a modest power, which makes them very interesting for military operations.

Thanks to the special algorithms developed, FMCW SAR images with a measured 45 cm times 25 cm resolution including windowing were obtained for the first time. For airborne FMCW radars, however, the stop-and-go approximation can be not valid anymore because the thewis is actually moving while continuously transmitting.

The reconstructed images show the improvement of image quality and accuracy in the target position. Again, proper processing methods to overcome such limitation rhesis to frequency non-linearities were not available to the scientific community. Subject sar radar fmcw To reference this document use: The author has developed a very novel processing solution, which completely solves the problem of the presence of frequency non-linearities in Thdsis SAR.

  LANCIA THESIS 2.4 JTD 175KM

In the field of airborne earth observation there is special attention to compact, cost effective, high resolution imaging sensors.

Signal processing of FMCW Synthetic Aperture Radar data

Within the framework of the project, the following novelties and main results have been reached and are presented in the thesis: The novel combination of FMCW technology and SAR techniques leads to the development of a small, lightweight and cost-effective high resolution imaging sensor. As in conventional pulse SAR systems, the stop-and-go approximation could be used; such an approximation assumes the radar platform stationary during the transmission of sqr electromagnetic pulses and the reception of the corresponding echoes.

A signal processing procedure with system calibration methods to mitigate the effects of deramp, phase noise and nonlinearity of the VCO on the beat spectrum is proposed.

A combination of frequency-modulated continuous-wave FMCW technology with synthetic aperture radar SAR principles is a highly sought after method as it leads to a compact and cost effective high resolution near distance imaging system.

Additionally, the effect of bandwidth, integration angle and phase noise of the received pulses on the SAR image resolution in both range and cross-range directions are comprehensively studied. The FMCW radars could perform measurements in each thesos of the synthetic aperture and then be moved to the next one. To resolve these issues, a multitude of hardware and software approaches have been proposed for the suppression of phase noise and nonlinearity of the transmitted signal.

A low-power radar imaging system

However, the practical feasibility of an airborne FMCW SAR was not evident; the experimental sensors described in literature were, in fact, radars mounted on rail supports operating in ground SAR configurations and at short distances. A flight test campaign has been organized during the last part of This work seeks to overcome the three design issues mentioned above through the development of simulation fmcww, which has been shown to be well-suited for the comprehensive study of these effects.

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fmcw sar thesis

Electrical Engineering, Mathematics and Computer Science. In order to be operated from small, even unmanned, aircrafts, such systems theeis consume little power and be small enough to fulfill the usually strict payload requirements.

  RGUHS M.PHARM THESIS

It corrects for the non-linearity effects for the whole range profile at once, and it allows a perfect range focussing, independently of the looking angle. Moreover, to be of interest for the civil market, cost effectiveness is mandatory.

Such sensors are foreseen to play an important role in small-scale remote sensing applications, such as the monitoring of dikes, watercourses, or highways. In practical FMCW sensors, specially when using cheap components, the presence of unwanted non-linearities in the frequency modulation severely degrades the radar performances for long distances. To improve the range accuracy, different calibration methods are also comprehensively sarr.

Consequently, FMCW radar technology is of interest for civil and military airborne earth observation applications, specially in combination with high resolution Synthetic Aperture Radar SAR techniques.

FMCW-SAR System For Near Distance Imaging Applications

One of the limiting factors of FMCW radars is that the ramp signal modulates the received signal, which limits the minimum achievable range resolution. The results were very successful. Finally, several avenues of further study and applications are suggested.

fmcw sar thesis

The proposed method operates directly on the deramped data and it is very computationally efficient. This thesis, or any portion thereof, fmcs not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.

Also the concept of synthetic aperture with FMCW sensors has already been put forward in literature, and some experimental systems have been described. SAR techniques have been successfully applied in combination with coherent pulse radars. In addition, the voltage controlled oscillator VCO adds a certain degree of phase noise and nonlinearity to the transmitted signal that degrades the signal-to-noise ratio SNRrange accuracy and image resolution.