Ground-based Imaging Radar for Landslide Monitoring 19 th October - PowerPoint PPT Presentation

Ground-based Imaging Radar for Landslide Monitoring 19 th October 2016 Gs. Ir. Assoc. Prof. Dr. Chan Yee Kit Associate Professor Center for Remote Sensing and Surveillance Technologies Multimedia University, Malaysia 1

Facts & Figures Highland Tower collapsed in 1993, Ulu Klang, Selangor, 48 killed China Banqiao dam’s failure, killed > 171,000 people in 1975 Landslides in KL, 2011, 12 people killed Bridge collapsed in Penang, 2013, 1 killed > 1 mil people exposed to landslide hazards every year > 21,000 landslide-prone areas in Malaysia (16,000 in Peninsular, 3,000 in Sabah, 2,000 in Sarawak) > 120,000 high-rise buildings over 12 stories tall > 48,000 dams over 15 m high > 250 long bridges over 2 km long, hundreds of thousands of bridges, high risk mining sites, … Rana Plaza, Bangladesh, collapsed in 2013 (killed 1,129) 2

Existing Ground-Truth Monitoring Systems 3D Laser Scanner Total Station Inclinometer These are ground-truth measurement instruments: q Labor intensive q Require maintenance on-site, thus increasing hazards to personnel re-entering potentially Tiltmeter high risk areas Extensometer 3

Urgent Need for Preventive Monitoring of Structural Health and Earth Environments ü Non-destructive – remote sensing ü High resolution – change detection in cm-mm ü Wide area coverage – complete 3D model ü All weather – 24/7 periodic monitoring ü Real-time online retrieval – early warning ü Low cost – affordable for developing countries 4

Remote Monitoring using GBSAR system Use synthetic aperture processing technique to produce high resolution temporal InSAR images 5

GBSAR System Parameter Design Parameter Design Value Operating Frequency 17.2 GHZ Bandwidth 400 MHz Waveform FMCW Polarization single Transmit Power 1 W Antenna Gain 16 dBi 3dB beamwidth 10 ° (azimuth), 10 ° (elevation) Synthetic Length 1.5 m Range Resolution 0.5 m Azimuth Resolution 5.8 mrad Maximum Sensing Distance 2000 m Sigma naught −20 dB SNR > 10 dB 6

Functional Block Diagram of GBSAR ! 7

GBSAR Prototype 8

Raw SAR Signal Processing: Pre-sum filter 1 0.5 0.4 0.3 0.5 1 0.2 0.1 0.5 range compression 0 0 0.4 0.5 − 0.1 0.3 − 0.5 − 0.2 0.2 0 − 0.3 0.1 − 1 − 0.4 0 − 0.5 − 0.5 − 0.1 0 1 2 3 4 5 − 3 x 10 − 0.2 − 1.5 0 0.5 1 1.5 2 2.5 − 1 4 x 10 − 0.3 − 0.4 − 0.5 − 1.5 0 1 2 3 4 5 0 0.5 1 1.5 2 2.5 − 3 Raw I&Q FMCW received signals x 10 4 x 10 65 65 60 60 80 35 55 55 70 30 60 50 50 25 50 20 40 45 45 15 30 10 20 40 40 5 10 0 0 35 35 5 10 15 20 25 30 35 10 15 20 25 30 35 30 30 0 100 200 300 400 500 600 700 800 900 1000 0 100 200 300 400 500 600 700 800 900 1000 Combining multiple range lines and perform azimuth compression 9

Preliminary Tests ! ! ! 10

Change Detection in mm Measured Accuracy < 5 mm 0.005 0 − 0.005 − 0.01 − 0.015 mm − 0.02 − 0.025 − 0.03 − 0.035 − 0.04 − 0.045 0 5 10 15 20 25 30 35 40 45 50 Step 5 8 20 6 6 18 16 7 4 14 Range Change Detection (mm) 8 12 2 10 9 8 0 6 10 4 − 2 2 11 0 5 6 7 8 9 10 11 − 2.5 − 2 − 1.5 − 1 − 0.5 0 0.5 1 1.5 2 2.5 Range Azimuth dR = λ d φ / 4 π 11

System Verification and Field Test 12

Change Detection: 5-15 mm change detected within a day! 2014-08-19 10:59 AM 2014-08-19 5:58 PM 13

Actual Test Site (Gunung Pass, Cameron Highland) 14

Installation at Test Site 15

Test Site: TS001 Gunung Pass − 100 − 110 − 120 − 130 − 140 − 150 − 160 − 170 − 180 − 190 − 200

Mosaic : VV, -4~4 degrees GBSAR Image Satellite Image from Google 17

Trihedral Location Trihedral T1(Large, Fixed): [4.5919070143, 101.3433433900] Altitude = 1320.83 m Trihedral T2 (Small, Adjustable): [4.5919913487, 101.3429884556] Altitude = 1316.69 m Distance from GBSAR to T1 = 1259 m Distance from GBSAR to T2 = 1244 m

Sample data set: 150523-110419L Background, No Trihedral

Sample data set: 150822-174259R Observed T1 at Observed T1 at (27.35 m, 1268.10 m) (27.35 m, 1268.10 m)

Sample data set: 150822-184126R Observed T2 at (-1.59 m, 1253.25 m)

Measured Displacement (0.5 mm/step) Fine adjustment of the trihedral T2 with 0.5 mm per step

Measured Displacement (0.5 mm/step)

0.5 mm change detection 0.5 0.4 0.3 0.2 Displacement (mm) 0.1 0 − 0.1 0.5 mm change -0.1 mm (before) − 0.2 +0.4 mm (after) − 0.3 0 10 20 30 40 50 60 70 80 90 Sample 24

Study Area TS02: MeiHua School, TW Sensing Distance: 500-1000 m Swath Width: 150-200 m Altitude: ~485-610 m

3D Optical View

3D Optical + GBSAR Image

3D Optical + GBSAR + LiDAR Image

Taipei Measurement Campaign (02-08 June, 2016) 測點 1 ：潮境中心 (KeeLong Test Site. 02-04 Jun) 測點 3 ：石門水庫大壩 測點 2 ：火炎山 (Fire (Simon Water Dam, 06 Jun) Hill Test Site, 05 Jun) 29

Taipei Measurement Campaign (02-08 June, 2016) 測點 4 ：烏來 (WuLai 測點 5 ：青埔捷運棒球場站 Test Site, 07 Jun) (CP LRT Station, 08 Jun) 30

Sample Results: Detection of Vibration at LRT Station 10mm -10mm 31

Taiwan Tao Yan Train Station 32

Changes Detection 4mm -4mm SRD

Observation Across Two Different Time T1 T2

Observation Across Two Different Time Zone T1 T2 2016/8/3 35

Summary § Ground movements and instabilities such as landslides, falling rocks can lead to considerable human and economic losses. § Continuous monitoring on high risk area is important to give insight into the mechanisms of land deformation. § In Malaysia, there are 21,000+ landslide-prone areas to be monitored. § A mmW GBSAR has been developed. It has 0.5 m × 5.8 mrad spatial resolutions, and change detection capabilities up to 5 mm. § The GBSAR is suitable tool for the land deformation detection, landslide monitoring as well as man made structure monitoring. 36

THANK YOU 37