OBSERVATIONS JUST AFTER THE GREAT EAST JAPAN EARTHQUAKE BY THE AIRBORNE SAR (PI-SAR2) OF NICT T. Kobayashi, T. Umehara, M. Satake, S. Kojima, J. Uemoto, T. Matsuoka, A. Nadai, and S. Uratsuka National Institute of Information and Communications Technology ( NICT ） , Tokyo, JAPAN IGARSS2011 July 28 TH4.T07
Outline 1. Introduction 2. Pi-SAR2 characteristics 3. Urgent observations by Pi-SAR2 4. Onboard Processor 5. SAR images 6. Summary Polarimetric and interferometric synthetic aperture radar (Pi-SAR)
1.Introduction The great east Japan earthquake occurred on March 11 ,2011. NICT conducted urgent observations of the damaged areas by an airborne X-band SAR system ( Pi-SAR2 ) on March 12 . The observation areas were scattered over a 500 km wide area. SAR images were processed in flight using the onboard processor . After landing, these SAR images were sent to the head office of NICT, distributed to headquarters for disaster control and uploaded to the website. The second flight was conducted on March 18 to detect the change of damaged areas and to cover the other areas.
2.Pi-SAR2 characteristics (specifications) Since 1997 Since 2009
image by the onboard processor Onboard image Kaya ohashi March 12 2011 Image size: 2 x 2 km Resolution: 0.3 m broken bridge
Sendai Airport on March 12 Pi-SAR2 color composite image 5km x 5km (Sendai Airport, Miyagi) RGB: HH , VH , VV 20000x20000x4bytex2=3.2Gbyte for each polarization Path no 2011031204-03 place name Sendai Airport Date (data take) March 12/, 2011 Location N38 deg 09’ 14’’, E140 deg 54’ 18’’ Altitude 8501 m Speed 192 m/s True heading -7.2deg Drift angle 8.28deg Incidence angle 38.7 -- 54.2 deg Image size (Az x Gr) 5.00 x5.00 km Pixel spacing (Az x Gr) 0.250 x 0.25 m Resolution Az/Sr 0.30 x 0.30 m
3. Urgent observations by Pi-SAR2 1st flight : 15path 7:30 – 10:45 JST March 12 2011 2nd flight : 13path 12:00 – 15:30 JST March 18 2011
SAR image on March 12 Flight Illumination image size: 25km x 5 km Sendai Path 4 on March 12, 2011 Line corresponding to flight path. Box corresponding to the observation area. N
A relationship in terms of location Tokyo NICT Nagoya Airport Center of shake The 9.0-magnitude earthquake and tsunami occurred on March 11 2011. NICT office is located in Koganei, Tokyo. Pi-SAR2 system is kept in Nagoya. Pi-SAR2 uses the airplane owned by a company in Nagoya.
Time table of urgent observation on March12 Event Handling Time Hrs from obs. Earth quake 14:46 - Negotiation of flight Setting up Pi-SAR2 system Traveling from Koganei to Nagoya Takeoff 07:30 - Observation 08:16 0 Onboard processing Landing 10:45 2.48 Preparing for sending data Receiving images@NICT 12:14 3.97 Preparing for data release Data Release 14:23 6.12
4.Onboard processor extraction: 2.5 min processing: 10 min for 2x2 km area by mode 1 about 4 min processing for 1x1 km area by mode 1 The Pi-SAR2 has an onboard processor and data transfer system. This onboard system offers SAR image with full spatial resolution Machine DELL Precision T7400 CPU Intel Xeon X5260(3.33GHz, 1333MHzFSB, 6MB L2 cashe) OS Red Hat Enterprise Linux 5 Memory 12Gbyte Disk SATA HDD(7200 回転 )
images by the onboard processor Onboard image Sendai Airport March 12 2011 Image size: 2 x 2 km
images by the onboard processor SAR images were processed in flight using the onboard processor . After landing, these SAR images were sent to the head office of NICT, distributed to headquarters for disaster control and uploaded to the website. P1:Onahama P10:Kesennuma P12:Abukumagawa P13:Natori P15:Shirakawa
5. SAR images Temporal Change March 12, 2011 March 18, 2011 Sendai airport area 5 x 5 km
Temporal Change of submersion area March 12, 2011 March 18, 2011 Submersion(under water) area decreased on March 18.
Comparison with aerial photos Photos taken by Geospatial Information Authority of Japan
Comparison with Submersion area area covered with water estimated by aerial photo (by Geospatial Information Authority of Japan) SAR image around Sendai airport
SAR image on March 18 Flight Illumination image size: 35km x 5 km Path 9 on March 18, 2011 N
Buildings collapsed by tsunami Upper map provided by http://cottostreet.blog.so-net.ne.jp/2011-04-24
7. Summary NICT conducted urgent observations for the great east Japan earthquake by Pi-SAR2 on March 12 and March 18 . SAR images were processed by the onboard processor . These SAR images were distributed to headquarters for disaster control on March 12 and uploaded to the website. http:// www2.nict.go.jp/pub/whatsnew/press/h22/announce110312/index.html Color composite images observed on March 12 and 18 are also available at the same website.
Thank you I would like to offer my deepest condolences on the victims of the east Japan earthquake. Acknowledgements: We thank NEC Corporation for the Pi-SAR2 system development and Diamond Air Service for the flight. operation.
Single-pass Intereferometry Amplitude Phase difference Unwrapped Phase difference Mt. Shinmoe, 5 x 5 km, observed on February 26, 2011
Pi-SAR and Pi-SAR2 NICT developed and operated the airborne p olarimetric and i nterferometric s ynthetic a perture r adar( Pi-SAR ) since 1996 with JAXA. The Pi-SAR made more than 100 observation flights since 1997. Over ten years experiences of NICT in development of Pi-SAR (X-band) and application research have indicated the effectiveness and limitation of remote-sensing of earth surface by existing airborne SAR systems, especially for disaster monitoring such as volcanic eruption, land-slide and flood. ・ Objective: To contribute to application research area such as disaster monitoring by improvement of the SAR system, NICT has developed new high performance airborne SAR system, “Pi-SAR2”since 2006.
Pi-SAR2 system (overview) Main H Antenna Main V Antenna left radome Sub V Antenna right radome SW HPA(TVTA) HPA(TVTA) TRX SGP System Control 2-Axis Driver Control Recorder IMU/GPS (POS AV610) Power Supply 2-Axis Driver EatherHUB Rack #1 Rack #2 2-Axis Driver Monitor
Pi-SAR2 system (Antenna & radome) ● Antenna: V and H polarization slotted waveguide antenna (668mm (Az) x 200mm(El)) ● 2-axis driver: Off-nadir angle (roll) : 40-60 deg Azimuth (yaw): ±9 deg Az. ang. velocity:0.1(min)-5(Max) deg/s ● Interferometricbaseline: 2.6 m (Pi-SAR: 2.3 m) Ground height accuracy under 2m are expected at inc. angle of 40deg at altitude of 10000m ( with phase error of 2deg and baseline error of 0.5 mm)
Pi-SAR2 system (TRX, TWTA) ● Transmitter (Tx) and Receiver (Rx) Gain control: manual/ auto Receive input level: 0dBm ～ -60dBm Receiver unit: 3 sets for Hm, Vm and Vs channel ● Switcher unit and high power amp. (TWTA) On board calibration function is in switcher unit. By using 2 sets of 8 kW (peak) TWT amplifier for H-and V-pol. transmission independently, transmission duty ratio of each TWTA is reduced. ● 2-Axis driver control Rack #1
Pi-SAR2 system (SGP) ● Signal generator and processor(SGP) Chirp pulse band width: 500/ 300/ 150MHz Receive sampling rate: 800/ 400/ 200MHz 3 sets of signal processor for Hm, Vm and Vs channel To achieve accurate signal processing , the clock of the D/A and A/D converters are determined as enough higher than the signal frequencies. Moreover, the real A/D conversion is adopted instead of the I-Q method to avoid the influence of non-orthogonality between I-Q channels. 8bit ADC with 1.6GHz sampling 12bit DAC with 1.6GHz Clock ● System control (SC) Rack #1
Pi-SAR2 system (Rcorder) ● on-board processor ● Monitor ● Power supply ● Data recorder Data rate: 200 MB/s (Max) x 3 channel Record media: 4TB 3.5 in. HD (500 GB x 8) for each channel I/O Interface: serial-FPDP Estimated data volume of 4 hour SAR observation: -> 3 TB per each channel serial FPDP(Front Pannel Data Port) Rack #2
Pi-SAR2 system (Operation) ● Planning and Operation Software ・ Observation plans are made by a laptop-PC with Japanese map. ・ Operation of observation is carried out by using the laptop-PC interface. ・ According to the observation plan, observation starts automatically with real time GPS position information.
Observation mode of Pi-SAR2 *In all modes, Pi-SAR2 acquires full polarimetric (HH/VV/HV/VH) and interferometric (VVs/HVs) data. *Values are estimated with the airplane altitude of 12000 m and the ground speed of 220 m/s Pi-SAR2 has polarimetric and interferometric functions with high spatial resolution of 0.3-0.6 m in along track (azimuth) direction and 0.3-0.5 m in cross track (slant-range) direction at X-band. Noise equivalent backscattering coefficient (NEσ0) will be kept under -27 dB in slant-range distance of 5-10km between incidence angles from 20 to 60 degree at the platform altitude of 12000 m. Observation mode Mode 1 Mode 2 Mode 3 Mode 0 Bandwidth 500 MHz 300 MHz 150 MHz 500 MHz method Strip map Strip map Strip map Sliding spotlight Slant range resolution 0.3 m 0.5 m 1.0 m 0.3 m Azimuth resolution 0.3 m (1look) 0.6 m (2looks) 0.6 m (2looks) 0.5 ～ 0.3 m (2looks) Swath width 5 ～ 10 km 7 ～ 10 km > 10 km 4 ～ 9 km Azimuth length － － － 3 ～ 7 km NE σ 0 < -23 dB < -27 dB < -30 dB < -25 dB
Specification of Pi-SAR/Pi-SAR2 Pi-SAR2 Pi-SAR (X-band) Center Frequency 9.65/9.55/9.55GHz) 9.55GHz Band width 500/300/150MHz 100/50MHz Weight 537kg (Include INS) 708kg (Include INS) Transmitter peak power 8kW 6.3kW Antenna size (Az x El) 668 x 200 mm 1065 x 200 mm Beam width (Az x El) 3deg x 35 deg 2.3deg x 40 deg Slant Range resolution 0.3/0.5/1.0m 1.5/3.0m Azimuth resolution 0.3/0.6/1.2m (1/2/4 look) 1.5/3.0m (4 look) Noise equivalent NRCS less than -23/-27/-30dB less than -40dB D/A conversion for chirp 12bit DAC with 1.6GHz Clock 10bit DAC with 246.9MHz Clock A/D conversion of Rx Real method 8bit ADC with 1.6GHz sampling I-Q separation method 8bit ADC with 123.45MHz sampling Data recording rate 600(200x3)MByte/sec Conduant TK400 64(32x2)MByte/sec Sony DIR-1000 Swath width (ground-range) 7.2/21/42km 5.6km (6ch mode 100MHz ) Receiving Channel 3ch(Vm, Hm, Vs) 2ch(Vm, Hm/Vs) Combination of data 6ch(Quad Pol.+XTI) 6ch(Quad Pol.+XTI) 2ch(XTI) 4ch(3ch pol.+XTI/Quad pol) Range of antenna rotation in Yaw ±9degrees ±6.5degrees Baseline for Cross-track interferometry 2.6m 2.3m Incidence angle 10 --65 deg. Variable 10 --75 deg. Variable Flight information Applanix POS AV610 Litton-92 navigation system
Breakdown of weight weight Main antenna 95 kg Sub antenna 95 kg Rack #1 157 kg Rack #2 162kg IMU/GPS 8 kg Wave guide etc. 20kg