FMCW SAR THESIS

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 the electromagnetic pulses and the reception of the corresponding echoes. 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. The results were very successful. 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 SNR , range accuracy and image resolution. To improve the range accuracy, different calibration methods are also comprehensively studied. SAR techniques have been successfully applied in combination with coherent pulse radars.

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 the electromagnetic pulses and the reception of the corresponding echoes. The author has developed a very novel processing solution, which completely solves the problem of the presence of frequency non-linearities in FMCW SAR. 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 proposed method operates directly on the deramped data and it is very computationally efficient.

FMCW-SAR System For Near Distance Imaging Applications

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.

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. To demonstrate the effectiveness and versatility of the proposed signal processing procedure, an S-band FMCW radar thexis, using off-the-shelf components, is designed for near distance target imaging using linear and circular SAR techniques.

asr

Within the framework of the project, the following novelties and main results have been reached and are presented in the thesis: A signal processing procedure with system calibration methods to mitigate the effects of deramp, phase noise and nonlinearity of the VCO fmcs the beat spectrum is proposed. Such sensors are foreseen to play an important role in small-scale remote sensing applications, such as the monitoring of dikes, watercourses, or highways.

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The results were very successful. Finally, several avenues of further study and applications are suggested. To improve the range tthesis, different calibration methods are also comprehensively studied.

fmcw sar thesis

A flight test campaign has been organized during the last part of Subject sar radar fmcw To reference this document use: Also the concept of synthetic aperture with FMCW sensors has already been put forward in literature, and some experimental dar have been described. 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 saar combination of FMCW technology and SAR techniques leads to the development of a small, lightweight and cost-effective high resolution imaging sensor.

In the field of airborne earth observation there is special attention to compact, cost effective, high resolution imaging sensors. The proposed method operates directly on the deramped data and it is very computationally efficient.

Signal processing of FMCW Synthetic Aperture Radar data | TU Delft Repositories

This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law. The author has developed a very novel processing solution, which completely solves thesus problem of the presence of frequency non-linearities in FMCW SAR. 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.

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.

Signal processing of FMCW Synthetic Aperture Radar data

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.

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The reconstructed images show the improvement of image quality and accuracy in the target position. In order to be operated from small, even unmanned, aircrafts, such systems must consume little power and tthesis small enough to fulfill the usually strict payload requirements.

The FMCW radars could perform measurements in each position of xar synthetic aperture and then be moved to the next one. In practical FMCW sensors, specially when using cheap thexis, the presence of unwanted non-linearities in the frequency modulation severely degrades the radar performances for long distances.

A low-power radar imaging system

To resolve these issues, a multitude of thesie and software approaches have been proposed for the suppression of phase noise and nonlinearity of the transmitted signal.

Moreover, to be of interest for the civil market, cost effectiveness is mandatory.

fmcw sar thesis

Skip to main content. Furthermore, such sensors are of military interest; reconnaissance tasks could be performed with small unmanned aerial vehicles UAVsreducing in this way the risk for one’s own troops. 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. 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 the electromagnetic pulses and the reception of the corresponding echoes.

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.

fmcw sar thesis

For airborne FMCW radars, however, the stop-and-go approximation can be not valid anymore because the platform is actually moving while continuously transmitting. SAR techniques have been successfully applied in combination with coherent pulse radars. 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.

Electrical Engineering, Mathematics and Computer Science.