Through-Wall Imaging With UWB Radar System - KEMT FEI TUKE

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4.1 Through-Wall TOA Estimation 52 Propagation time [ns] Distance from the wall [m] 4.4 8.9 13.3 17.8 1 0.8 0.6 0.4 a) Reflection from wall 50 100 150 200 250 300 350 400 Number of scans b) Antenna distance from the wall Wdi 0.2 0 50 100 150 200 250 300 350 400 Number of scans Fig. 4.1.7: Estimation of antenna distance from the wall. a) Reflection from the Wall, B-scan. b) Antenna distance from the wall Wdi. wall is shown in Fig. 4.1.7 a). The estimation of Wdi is shown in Fig. 4.1.7 b). Estimated antenna distance from the wall can be used during TOA computation required for imaging. 4.1.6 Antenna Beam Compensation Before the migration can be done, the antenna beam should be compensated according to the Section 2.5.13. Measurements of antenna direction proprieties leads to antenna footprint as a weight function depending on the antenna look angle: w = footprint(φ) (4.1.15) An example of horn antenna footprint is shown in Fig 4.1.8 a). Because the positions of the transmit and receive antennas are not the same in bistatic case (Fig 4.1.8 b)), two different weights for both antennas must be included in the formation of the SAR imaging algorithm: I(xT , zT ) = 1 N N� w1w2BP Cn (X, k = T OAn) (4.1.16) n=1
4.1 Through-Wall TOA Estimation 53 Antenna looking dirrection 180˚ 90˚ 270˚ � 0˚ Z Wall TX � � Target a) b) Fig. 4.1.8: a) The example of horn antenna footprint. b) Bistatic through-wall model. where w1 = footprint(φ1) and w2 = footprint(φ2). The whole implementation of the antenna footprint to the SAR imaging increase the computation complexity only negligibly. 4.1.7 Measurements Results The influence of the wall on imaging results is illustrated on two experiments. For testing of the proposed algorithm the 2D SAR measurements were chosen. The measurements were done with the 9 GHz M-sequence UWB radar system [43, 116, 118] described in Section 2.1.3. Bistatic model with the double-ridged horn antennas was used. For bistatic system the dtot has to be computed twice, for transmitter-target flight distance and for target-receiver flight distance: RX � � P 1 dtot bist = dtot T X2T + dtot T 2RX. (4.1.17) All the preprocessing and calibration steps described in Section 2.4 were undertaken. The irregular trolley movement was compensated, as well as antenna beam. The migration with a simple geometrical approach described in Section 2.5.2 called SAR imaging was used to transform time domain into the spatial domain. The wall was compensated by the proposed algorithm. Scenario 1 is a simple scenario, where the measured object is in parallel with the scanned wall. The measured room was approximately 4 m × 5 m large, with the wall thickness of about 0.2 m. The wall was made of bricks with relative permittivity approximately εrw = 4. Distance between the centers of antennas P 2 X
Page 1 and 2:
TECHNICAL UNIVERSITY OF KOˇSICE Fa
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Acknowledgement I give a sincere gr
Page 5 and 6:
CONTENTS v 3 Goals of Dissertation
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LIST OF FIGURES vii List of Figures
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LIST OF FIGURES ix 4.4.3 Aquarium f
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LIST OF FIGURES xi List of Symbols
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LIST OF FIGURES xiii kx - Horizonta
Page 15 and 16: Chapter 1 Introduction 1.1 Motivati
Page 17 and 18: 1.3 Thesis Organization 3 In additi
Page 19 and 20: Chapter 2 State Of The Art 2.1 UWB
Page 21 and 22: 2.2 Through-Wall Radar Basic Model
Page 23 and 24: 2.3 SAR Scanning 9 and shall remain
Page 25 and 26: 2.4 Calibration and Preprocessing 1
Page 27 and 28: 2.4 Calibration and Preprocessing 1
Page 29 and 30: 2.5 Radar Imaging Methods Overview
Page 55 and 56: Chapter 4 Selected Research Methods
Page 57 and 58: 4.1 Through-Wall TOA Estimation 43
Page 65: 4.1 Through-Wall TOA Estimation 51
Page 71 and 72: 4.2 Measurements of the Wall Parame
Page 81 and 82: 4.3 Highlighting of a Building Cont
Page 91 and 92: 4.4 Measurements of the Practical S
Page 99 and 100: 5.1 Conclusion and Future Work 85 5
Page 101 and 102: 50 100 150 200 250 300 350 400 Z 45
Page 103 and 104: 50 100 150 200 250 300 350 400 Z 45
Page 105 and 106: 50 100 150 200 250 300 350 400 Z 45
Page 107 and 108: 50 100 150 200 250 300 350 400 Z 45
Page 109 and 110: Z [cm] Z [cm] 50 100 150 200 250 30
Page 111 and 112: Z [cm] 50 100 150 200 250 300 b) Em
Page 113 and 114: BIBLIOGRAPHY 99 [13] T. W. Barrett,
Page 115 and 116: BIBLIOGRAPHY 101 [46] G. Derveaux,
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BIBLIOGRAPHY 103 [81] S. Kidera, T.
Page 119 and 120:
BIBLIOGRAPHY 105 [115] J. Sachs, M.
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BIBLIOGRAPHY 107 [150] O. Yilmaz, S
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Through-Wall Imaging With UWB Radar System - KEMT FEI TUKE

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