In order to be operated from small, even unmanned, aircrafts, such systems must consume little power and be small enough to fulfill the usually strict payload requirements. The results were very successful. Finally, several avenues of further study and applications are suggested. Electrical Engineering, Mathematics and Computer Science. In the field of airborne earth observation there is special attention to compact, cost effective, high resolution imaging sensors. 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.

Subject sar radar fmcw To reference this document use: 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. 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. The author has developed a very novel processing solution, which completely solves the problem of the presence of frequency non-linearities in FMCW SAR. 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. In the field of airborne earth observation there is special attention to compact, cost effective, high resolution imaging sensors.

A low-power radar imaging system

This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written war of the copyright owner, except to the extent permitted by Canadian copyright law.

It corrects for the non-linearity effects for the whole range theais at once, and it allows a perfect range focussing, independently of the looking angle. 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.

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.

The novel combination of FMCW technology and SAR techniques leads to the development of a small, lightweight and cost-effective high resolution imaging sensor. Finally, several avenues of further study and applications are suggested.

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In order to be operated from small, even unmanned, aircrafts, such systems must consume little power and be small enough to fulfill the usually strict payload requirements.

Zar sar radar fmcw To reference this document use: 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.

Electrical Engineering, Mathematics and Computer Science. The FMCW radars could perform measurements in each position of the synthetic aperture and then theeis moved to the next one.

fmcw sar thesis

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. 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 The results were very successful. One of the limiting factors of FMCW radars is that the ramp signal modulates the received signal, which limits the minimum achievable range resolution. Within the framework of the project, the following novelties and main results have been reached and saar 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 on the beat spectrum is proposed.

The reconstructed images show the improvement of image quality sarr accuracy in the target position. They consume little power and, due to the fact that they are continuously operating, they can transmit a modest power, fcw makes them very interesting for military operations. The author has developed a very novel processing solution, which completely solves the problem of the presence of frequency non-linearities in FMCW SAR. Moreover, to be of interest for the civil market, cost effectiveness is mandatory.

Also the concept of synthetic aperture with FMCW sensors has already been put forward in literature, and some experimental systems have been described.

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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. 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. Again, proper processing methods to overcome such limitation due to frequency non-linearities were not available to the scientific community.

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. Such sensors are foreseen to play an important role in small-scale remote sensing applications, such as the monitoring of dikes, watercourses, or highways.

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.

Signal processing of FMCW Synthetic Aperture Radar data

SAR techniques have been successfully applied in combination with coherent pulse radars. Skip to main content.

fmcw sar thesis

The proposed method operates directly on the deramped data and it is very computationally efficient. To demonstrate the effectiveness and versatility of the proposed signal processing procedure, an S-band FMCW radar system, using off-the-shelf components, is designed for near distance target imaging using linear and circular SAR techniques.

FMCW-SAR System For Near Distance Imaging Applications

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. 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 thesiz resolution near distance imaging system. 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.