IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L 1 THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L July 29, 2011 IGARSS 2011, Vancouver, Canada Takashi Fujimura, Hideharu Totsuka, Norihiro Imai, Shingo Matsuo, Tsunekazu Kimura (NEC Corporation) Tomoko Ishi, Yoshitaka Oura (NEC Aerospace Systems, Ltd) Masanobu Shimada (Japan Aerospace Exploration Agency)

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L 2 Contents 1. Introduction 2. Bistatic SAR Experiment 3. Analysis of Image 4. Conclusion

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L 3 1. Introduction Some Spaceborne/airborne bistatic SAR experiments were tried. The first bistatic SAR experiment using spaceborne PALSAR and airborne Pi-SAR-L on February 27th, Background Few reports about bistatic SAR with other than TerraSAR-X. M. Rodriguez-Cassola, etc., “ Bistatic TerraSAR-X / F-SAR Spaceborne-Airborne SAR Experiment: Description, Data Processing, and Results ” IEEE Trans. on G.E., vol.48, No.2 I. Walterscheid, etc., “ Bistatic SAR Experiments With PAMIR and TerraSAR-X - Setup, Processing, and Image Results ”, IEEE Trans. On. G.E. vol.48, No.8 and so on. First report : “ The First Bistatic SAR Experiment with the Spaceborne SAR : PALSAR and the Airborne SAR : Pi-SAR-L ”, SANE, IEICE

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L 4 1. Introduction Pi-SAR-L has NO special function for bistatic SAR observation. (function for receiving time synchronization) Bistatic SAR operation and image processing could succeed only with the followings. The appropriate choice of the experiment conditions The appropriate setting of control parameters of Pi-SAR-L The appropriate image processing method Summary of Experiment Analysis : 3 features of This Bistatic SAR image 1.Higher S/N 2.Lower Az resolution 3.Difference of detected targets

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L 5 2. Bistatic SAR Experiment (1) PALSAR and Pi-SAR-L Spaceborne SAR : Transmitter Freq. : L-band Operation : Jan, 2006 – April, 2011 Res. : 10 / 20 / 30 / 100 m Swath : 70 / 70 / 30 / 350 km Pol. : Single/Dual/Quad/Single Airborne SAR : Receiver Freq.X-bandL-band Operation Res.1.5 or 3m3 - 20m Swath 20 – 40km5 - 40km Pol.Quad Organization JAXANICT ALOS (Daichi) / PALSAR Pi-SAR PALSAR and Pi-SAR-L have no special hardware for the bistatic SAR. Quad

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L 6 2. Bistatic SAR Experiment (2) The Experiment Conditions North South (Descending) ParametersPALSARPi-SAR-L 1Date, TimeFeb. 27th(Sat), :23:17(+/-30sec) (Japan Standard Time) 2AreaAround Okazaki city, Aichi, Japan 3Observation mode High Resolution Experiment mode (Reception only) 4PolarizationHHH 5Height700 km8500 m 6Swath70 km- 7Off-nadir Angle 34.3 degrees 40 degrees 8PRF Hz996.9 Hz 9Velocity7500 m/s200 m/s 10STCOFF 11AGC/MGCMGC 12MGC ATT25dB 13Transmitted Pulse Width 27 micro sec No Transmission 14Transmitted Band Width 28 MHzNo Transmission 15Received Band Width 28 MHz30 MHz PALSAR (transmitter) : FBS mode Pi-SAR-L (receiver) : reception only experiment mode

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L 7 2. Bistatic SAR Experiment (3) The Experiment Area (Okazaki city in Japan) North PALSAR ’ s observation area (c) “Digital Japan” URL Osaka Tokyo Nagoya Kyoto Yahagi-gawa River Oto-gawa RiverTomei Expressway Japan National Route 1 (Tokaido Road) Tokaido Main Line (Railway) Near the center of Japan Important place for transportation in Japan

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L 8 2. Bistatic SAR Experiment (4) Configuration and Result Receiver Signal Processor (A/D) Antenna Recorder Pi-SAR-L Chirp Generator Transmitter Antenna Earth Surface PALSAR The both of the video signal and A/D sampling data had been set adequately. Receiving duty ~50% PRF Hz PRF Hz Video Signal Level TelemetryA/D sampling data (in 1 PRI) Time (UTC) Code ( 1 Code is 2.47mV)

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L 9 2. Bistatic SAR Experiment (5) Bistatic Image PALSAR monostatic SAR imagePALSAR/Pi-SAR-L bistatic SAR image This bistatic SAR image has three features. 1. Higher S/N, 2. Lower Az resolution, 3. Difference of detected targets Az

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L Analysis of Image (1) Higher S/N Note : the images after gamma correction PALSAR monostatic SAR imagePALSAR/Pi-SAR-L bistatic SAR image

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L Analysis of Image (1) Higher S/N Note : the images after gamma correction Road Watercourse Sandbar Difference between sandbars and watercourses appears in bistatic image. but these can not be found in monostatic image. Reason : Received signal level was high because of short distance. Yahagi-gawa River ?? PALSAR monostatic SAR imagePALSAR/Pi-SAR-L bistatic SAR image

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L Analysis of Image (2) Lower Azimuth Resolution The narrow roads in the monostatic SAR image are clearer than the ones in the bistatic SAR image. Az Profile (Next page) Unfortunately the azimuth resolution of the bistatic SAR image seems to be lower than that of the monostatic SAR image. Reason : Pi-SAR-L was not changed for simple feasibility trial. PALSAR monostatic SAR imagePALSAR/Pi-SAR-L bistatic SAR image

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L Analysis of Image (2) Lower Azimuth Resolution The possible reasons belong to the unchanged hardware mainly. 1.The shortage of sampling data  Pi-SAR-L has no function for the receiving time synchronization.  Received data by Pi-SAR-L has about only half of the original signal. 2.The instability of two oscillators of PALSAR and Pi-SAR-L  Oscillators of two SARs have no linkage for synchronization. 3.The relative motion between ALOS and the aircraft  SAR processor has the excellent motion compensation function.  But the influence of the relative motion may be left. Az Resolution is low in bistatic image. The monostatic SAR image : 4.6 m The bistaic SAR image : 8.4 m 8.4m 4.6m Bistatic Monostatic Az Profile

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L Analysis of Image (3) Difference of Detected Targets There are large differences of image at the yellow circles. Reason : The incidence angles were different and/or S/N was high. PALSAR monostatic SAR imagePALSAR/Pi-SAR-L bistatic SAR image

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L Analysis of Image (3) Difference of Detected Targets (Roof of Houses) PALSAR monostatic SAR imagePALSAR/Pi-SAR-L bistatic SAR image

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L Analysis of Image (3) Difference of Detected Targets (Roof of Houses) PALSAR monostatic SAR imagePALSAR/Pi-SAR-L bistatic SAR image

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L Analysis of Image (3) Difference of Detected Targets (Roof of Houses) Structures is dark at the left image but is bright at the right image. (c) “Digital Japan” URL Note : the images after gamma correction PALSAR monostatic SAR imagePALSAR/Pi-SAR-L bistatic SAR image

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L Analysis of Image (3) Difference of Detected Targets (Roof of Houses) (c) Google This residential were bright. The roofs of the houses will be strongly reflected, because of the incidence angle. PALSAR/Pi-SAR-L bistatic SAR image

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L Analysis of Image (3) Difference of Detected Targets (Bridges) PALSAR monostatic SAR imagePALSAR/Pi-SAR-L bistatic SAR image

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L Analysis of Image (3) Difference of Detected Targets (Bridges) “Digital Japan”, PALSAR monostatic SAR imagePALSAR/Pi-SAR-L bistatic SAR image

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L 21 Note : the images after gamma correction 3. Analysis of Image (3) Difference of Detected Targets (Bridges) All bridges on the map appear in the bistatic SAR image. It is difficult to detect two bridges in the monostatic SAR image. Its reason will be the different incidence angle and high S/N. “Digital Japan”, PALSAR monostatic SAR imagePALSAR/Pi-SAR-L bistatic SAR image

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L Analysis of Image (3) Difference of Detected Targets (Bridges) The width of this bridge : ~ 2 m << PALSAR resolution (10m/2look) The monostatic image : not clear. The bistatic image : clear. Reason : difference of incidence angles and/or high S/N. Note : the images after gamma correction PALSAR monostatic SAR imagePALSAR/Pi-SAR-L bistatic SAR image

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L Conclusion The first PALSAR / Pi-SAR-L bistatic SAR experiment was succeeded. Bistatic SAR observation was possible without special functions. This bistatic SAR image has 3 features. 1. S/N is better, because of the short distance. 2. The azimuth resolution is lower, because of the unchanged hardware without synchronization. 3. Some different targets can be detected, because of the different incidence angles and/or high S/N. Future Work Unfortunately ALOS has been lost in this April. As future work, the next experiment is expected with ALOS-2 and Pi-SAR-L2 under development.

IGARSS2011 : FR3.T01.1: THE BISTATIC SAR EXPERIMENT WITH ALOS / PALSAR AND Pi-SAR-L 24 Thank you for your attention.