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Furthermore, such sensors are of military interest; reconnaissance tasks could be performed with small unmanned aerial vehicles UAVs , reducing in this way the risk for one’s own troops. 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. 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. 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. For airborne FMCW radars, however, the stop-and-go approximation can be not valid anymore because the platform is actually moving while continuously transmitting. 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. Furthermore, such sensors are of military interest; reconnaissance tasks could be performed with small unmanned aerial vehicles UAVs , reducing in this way the risk for one’s own troops. 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. Such sensors are foreseen to play an important role in small-scale remote sensing applications, such as the monitoring of dikes, watercourses, or highways. 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. 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.

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 thssis short distances.

The novel tbesis of FMCW technology and SAR techniques leads to the development of a small, lightweight and cost-effective high resolution imaging sensor. The reconstructed images show the improvement of image quality and accuracy in the target position.

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

fmcw sar thesis

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

Electrical Engineering, Mathematics and Computer Science. 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. 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.

FMCW-SAR System For Near Distance Imaging Applications

SAR techniques have been successfully applied in combination with coherent pulse radars. 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 thwsis.

Finally, several avenues of further study and applications are suggested.

fmcw sar thesis

Such sensors are foreseen to play an important role in small-scale remote sensing applications, such as the monitoring of dikes, watercourses, sra highways. The FMCW radars could perform measurements in each position of the synthetic aperture and then be moved to the next one.

Moreover, thesi be of interest for the civil market, cost effectiveness is mandatory. The results were very successful. 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. 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.

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 platforms, which has been shown to be well-suited for the comprehensive study of these effects.

Signal processing of FMCW Synthetic Aperture Radar data

Again, proper processing methods to overcome such limitation due to frequency non-linearities were not available to the scientific community. One of the limiting factors of FMCW radars is that the ramp signal modulates the received signal, which limits the minimum achievable range resolution.

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Furthermore, such sensors are of military interest; reconnaissance tasks could be performed with small unmanned aerial vehicles UAVsreducing in this way the risk fncw one’s own troops. 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 proposed method operates directly on the deramped data and it is very computationally efficient. The author has developed a very novel processing solution, which completely solves the problem of the presence of frequency non-linearities in FMCW SAR.

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

Subject sar radar fmcw To reference this document use: To improve the range accuracy, different calibration methods are also comprehensively studied. 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 platform is actually moving while continuously transmitting.

fmcw sar thesis

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.

Also the concept of synthetic aperture with FMCW sensors has already been put forward in literature, and some experimental systems have been described. Within the framework of the project, the following novelties and main results have been reached and are presented in the thesis: They consume little power and, due to the fact that they thesos continuously operating, they can transmit a modest power, which makes them very interesting for military operations.

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.