The National Institute of Information and Communications Technology (NICT) has been conducting research and development of a third-generation airborne synthetic aperture radar (Pi-SAR X3) since 2016. Pi-SAR X3 improves the resolution (30cm) of the second-generation airborne SAR (Pi-SAR2 [1]). It can observe the Earth's surface with a resolution of 15 cm. This paper reports on the design and development status of Pi-SAR X3. In addition, The results of test observations performed to verify the operation of the instrument are reported and images obtained from the test observations are presented. In the test observation, the ground surface was observed at 15 cm and 30 cm resolution, and the advantages of the improved resolution are discussed by comparing the two images.

The east coast of Japan was heavily damaged in a wide area by the tsunami after the eastern Japan great earthquake on March 11, 2011. NICT conducted observations of the damaged areas by an airborne X-band SAR system (Pi-SAR2: polarimetric and interferometric SAR 2). Pi-SAR2 is high resolution of 0.3 m (slant-range). These SAR images of Pi-SAR2 are useful to detect the destruction of buildings and bridges and to identify flooded areas from the viewpoint of high resolution. We continuously observed the damaged area by Pi-SAR2 to monitor the reconstruction.In this paper we describe issues in the detection of the damaged area by the earthquake and tsunami with high resolution SAR data of Pi-SAR2 in 2011 and improvements.

This paper reports the preliminary analysis of the repeat track interferometry by Pi-SAR2 with RF-NAVI. First, the relationship between the correlation coefficient and the observation conditions such as the baseline length and the antenna look direction was investigated by using the observation data acquired for initial testing for CCD and tomography. In addition, the relationship between the repeat track radar interferogram and the observation conditions was investigated. As a result, the deformation of stable natural reflectors and permanent scatters might be detected using the repeat track radar interfereometric SAR data within 30m in the baseline length.

NICT developed the airborne X-band SAR system (Pi-SAR2) in 2008. It has polarimetric and interferometric functions with high spatial resolution of 0.3m. We demonstrated volcano monitoring using DEM generated by single-pass interferometry function of Pi-SAR2. In this paper we describe coherent change detection by repeat-pass interferometry function of Pi-SAR2. We improved the repeatability of flight path by introducing the guideline system and obtained high coherence image. In flight experiments we detected the footprint on the lawn in the coherence image.

An X-band airborne SAR, Pi-SAR2, has been developed by NICT. It can make polarimetric and interferometric observation with very high spatial resolution of 0.3m. Since 2013, NICT has carried out collaborating observations on research proposals selected for the Pi-SAR2 Research Announcement. Polarimetric SAR data analysis is a key issue among them, therefore we have made polarimetric calibration in each observation period.

This paper addresses the evaluation of the digital elevation model (DEM) generated by single pass SAR interferometry using an X-band airborne SAR (Pi-SAR2). In this paper we describe the evaluation experiments by using corner reflectors and show the result of the height accuracy on DEM by the cross-track interferometric function of Pi-SAR2.

A heavy rainfall was observed by the NICT X-band airborne synthetic aperture radar (SAR), Pi-SAR2. In the Pi-SAR2 image there are features attributed to both backscattering from the rainfall and attenuation by the rainfall, as published for the TerraSAR-X (spaceborne X-band SAR) obaservation. Those features induced by the rainfall are evaluated with the Pi-SAR2 polarimetric image data. It is also taken into account how movement of the raindrops affects its SAR imagery.

This paper addresses the generation of the digital elevation model (DEM) by radar interferometry using an airborne SAR data observed from different directions. We demonstrate monitoring an active volcano (Mt. Shinmoe, Japan) by radar interferometry of Pi-SAR2. We improved the part of shadow on DEM by using SAR data observed from four different directions. Furthermore we detected the change of ground height inside crater by comparing the data on February and October in 2011.

The National Institute of Information and Communications Technology (NICT) developed an airborne X-band SAR system (Pi-SAR2: polarimetric and interferometric SAR 2) to monitor the earth's environment and disasters [1]. Pi-SAR2 has polarimetric and interferometric functions with high spatial resolution of 0.3m [2]. In this paper we describe the single-pass interferometric function of Pi-SAR2 and show the performance evaluation on the interferometric function of Pi-SAR2 by using corner reflectors. Moreover we describe the volcanic monitoring by using interferometric SAR.

The great east Japan damaged the east coast of Japan severely. NICT conducted urgent observations of the damaged areas by an airborne X-band SAR system (Pi-SAR2: polarimetric and interferometric SAR 2). In this paper we describe the detection of the damaged area by the earthquake and tsunami with polarimetric SAR data of Pi-SAR2. The space resolution of Pi-SAR2 is 0.3 m (slant-range) [1][2]. These SAR images of Pi-SAR2 are useful to detect the destruction of buildings and bridges and to identify flooded areas from the viewpoint of high resolution. We continue to observe the damaged area by Pi-SAR2 to monitor the reconstruction.

A 9.0-magnitude earthquake occurred off the pacific coast of Tohoku area of Japan, in March 2011. Accompanied with the subsequent tsunami, it caused a lot of casualties and damages in the coast area. We conducted urgent observations of the damaged areas with an airborne X-band SAR system, Pi-SAR2, immediately after the earthquake, on March 12 and the following dates. The Pi-SAR2 is a fully polarimetric airborne radar, with high spatial resolution of 0.3 m. We found the high resolution radar images, with multi-temporal observations, are quite useful to estimate the area flooded by the tsunami and its changes. Also found is capability of the polarimetric radar images to estimate the amount of a pile of debris that is one of the greatest concerns for the residents.

The dependency of backscattering from ocean surface on wind direction under low wind speed (5m/s) is analyzed using observation data by an airborne dual-frequency SAR in the Land X-bands. The NRCS difference between up- and down-wind conditions depends on the incidence angle in the X-band HH polarization, though that in the VV polarization, the NRCS difference is almost zero. Moreover, the NRCS difference between parallel- and cross-wind conditions in the VV polarization is greater than that in the HH polarization. Though the dependency of the NRCS in the L-band on the wind direction is smaller than that in the X-band, the NRCSs in the L-band cross polarizations under the cross-wind condition is greater than that under the parallel-wind condition. The polarization ratio (PR) difference between up- and down-wind directions depends on the incidence angle as the incidence angle dependency in the X-band HH polarization. The dependency of the PR in the L-band on wind direction is also weaker than that in the X-band. The results suggest the possibility of ocean wind measurement using the polarimetric SAR in the X-band and/or using the dual-frequency SAR.

In the National Institute of Information and Communications Technology, Japan (NICT), we have developed an advanced X-band airborne synthetic aperture radar (SAR) system, Pi-SAR2, since 2006, to succeed the X-band polarimetric and interferometric airborne SAR, Pi-SAR. The Pi-SAR2 has a higher spatial resolution of 0.3-0.6 m in the azimuth direction and 0.3-0.5 m in the range direction, as well as polarimetric and interferometric observation functions. The calibration experiments of the Pi-SAR2 were carried out as a part its test flights in December 2008 and February 2010. Calibration targets were deployed on a runway of the Taiki Aerospace Experiment Field in Hokkaido, Japan, to be observed.

The synthetic aperture radar (SAR) has been utilized for monitoring natural disaster areas because the SAR observation can be performed irrespective of the daylight and weather conditions. To reduce the time from observation to distributing SAR images to the headquarters for disaster control and disaster area, we have developed an onboard processor which is capable of doing a full-spec processing for the airborne SAR called as the polarimetric and interferometric SAR (Pi-SAR2) since 2009. We demonstrated that the developed onboard processor is effective to reduce the time from observation to distribution and the SAR image can be transferred to the ground within 15 min after observation via the communication satellite called as the engineering test satellite VIII (ETS-VIII) in the experiments on March 2011.

NICT (National Institute of Information and Communications Technology, Japan) have developed a high performance airborne SAR system (Pi-SAR2) since 2006, as a successor to the Pi-SAR (X-band). 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. In this paper we report the ground based calibration experiment using active radar calibrators (ARC) and corner reflectors (CR) in conjunction with the Pi-SAR2 test flight.

The dependencies of the backscattering from the ocean surface on the wind direction are analyzed by using the Pi-SAR under weaker wind condition (5 m/s) than the former analysis under stronger wind as 14 m/s. In the X-band HH polarization, the dependency of the normalized cross section (NRCS) on wind direction depends on the incidence angle, differently from the former analysis. In the X-band VV polarization, the NRCS represents weak incidence angle dependency as same with the former analysis. As a result, the dependency of the polarization ratio (PR) in the X-band on the wind direction also depends on the incidence angle. In the L-band, the dependencies of the NRCS and the PR are also weak, same as the former analysis.

These days, the space-borne SAR becomes one of the powerful instruments to observe the earth surface. On the other hand, a airborne SAR is also important for development of SAR system and analysis technique. Moreover, airborne SAR is able to make immediate observation of disaster area. The National Institute of Information and Communications Technology (NICT) has been developing the new airborne synthetic aperture radar: Pi-SAR2 since 2006. The Pi-SAR2 is an airborne X-band polarimetric and cross-track inter-ferometric SAR with sub-meter spatial resolution. The spatial resolution is measured less than 0.5m using some corner reflectors. The Pi-SAR2 system were completed and began the operation in autumn 2008.

The normalized radar cross section (NRCS) of ocean surface is measured from three directions of illumination by an air-borne dual-frequency synthetic aperture radar (SAR) in the L- and X-bands, and the dependency of the NRCS and the polarization ratio on the relative wind direction is analyzed. In the X-band, the dependencies of the NRCSs in the parallel polarizations are different each other. The NRCS in the X-band HH polarization has difference between the up-and down-wind conditions, though that in the VV polarization the NRCSs for the up- and down-wind conditions are almost same. The dependency of the NRCS in the L-band is smaller than that of the X-band. The polarization ratio in the X-band shows the dependency on the wind direction with difference between the up- and down-wind conditions, though that in the L-band is not apparent. The results suggests the possibility of ocean wind measurement by the polarimetric SAR in the X-band.

The normalized radar cross section (NRCS) of ocean surface is measured from three directions of illumination by an airborne dual-frequency synthetic aperture radar(SAR) with L- and X-band, and the dependency of the NRCS and the polarimetric ratio on the relative wind direction is analyzed. In X-band, the NRCSs in parallel polarizations represent the dependency on the relative wind direction. The NRCS in HH polarization of X-band has difference between upwind and downwind condition, though that in VV polarization the NRCSs for upwind and down wind condition are almost same. The wind dependency of the NRCS in L-band is smaller than that of X-band. The polarimetric rate in X-band shows the wind dependency with small difference between upwind and downwind conditions, though that in L-band is not apparent. The results suggests the possibility of measurement of ocean winds only using the polarimetric SAR in X-band. Moreover, the small dependency of the NRCS in L-band suggests the possibility of the wind speed measurement over the ocean.

Polarization-selective dihedrals are developed for poalrimtric calibration of the PALSAR. The PALSAR is the first spaceborne polarimetric SAR boarded on the ALOS satellite launched in January 2006. This paper presents calibration experiments of PALSAR with the dihedrals in the ALOS initial calibration and validation phase. The reflectors are deployed in open fields of Tomakomai forest, to be imaged by not only the PALSAR but also the airborne polarimetric SAR, Pi-SAR. synthetic aperture radar (SAR)

A HF long-range (over 200 km) ocean radar system, developed by Japan's National Institute of Information and Communications Technology, was used to observe the Kuroshio surface current in the southern part of the East China Sea. The observations began in July 2001. We show the relationship between the antenna aperture length (beam-width) and the accuracy of Kuroshio surface current speeds measured using post-processed signals received by the radar.

The Phased-Array L-Band SAR (PALSAR) aboard the Advanced Land Observing Satellite (ALOS) is capable of globally acquiring fully polarimetric data. In order to confirm the ability of L-band polarimetric synthetic aperture radar (SAR) to investigate sea ice before the ALOS launch, we conducted a field experiment using an airborne Polarimetric and Interferometric SAR (Pi-SAR) in the Sea of Okhotsk in 1999. This paper presents the analyzed results of data acquired in that experiment. The extracted polarimetric parameters of several ice types suggested that polarimetric coherences and phase differences between right-right (RR) and left-left (LL) are good candidates for discriminating ice types. The polarimetric anisotropy as well as the beta angle of the first eigenvector calculated in the polarimetric decomposition procedure are alternative parameters that are sensitive to ice type differences. Due to the low depolarization characteristics of open water, it could be discriminated from sea ice by scattering entropy in all incidence angle ranges. From the relation between ice thickness and the polarimetric parameters, we found that backscattering coefficients and vertical (VV) to horizontal (HH) backscattering ratio are highly correlated with ice thickness. Since the ratio is sensitive to ice surface dielectric constants, a simple simulation using the integral equation method surface model was conducted by using the physical parameters of typical sea ice. A two-dimensional ice thickness map was derived from an empirical relation between the VV-to-HH backscattering ratio and ice thickness.

A long-range (200 km) high-frequency (HF) ocean radar system was developed by Japan's Communications Research Laboratory (CRL) to monitor the Kuroshio upstream region of the East China Sea. Sea surface observation began in July 2001. In this paper, we present the validation results of surface currents obtained by the radar in comparison with currents measured using a moored current meter. We also present the results of observing temporal variations in the Kuroshio over a year and the surface currents induced by a strong typhoon.

We propose a new real-time self-localization method for a mobile robot equipped with an omni-directional camera in a dynamically changing environment. This method uses direction of two landmarks and dead reckoning. Multiple localization process in parallel results robust and accurate localization. The proposed method applies to the soccer robot in the RoboCup middle-size league and an experimental result indicates that the approach is reliable.

Describes a dexterous and robust manipulation system with a multi-fingered hand. The system is composed of a real-time pose estimation of an object manipulated by the hand, a precise manipulation using fingertip with rolling contact, motion primitives for mechanical assembly, and error-recovery strategies based on the task observation function. The system architecture and experimental results are shown.

We describe a real-time model-based sensing system to estimate the pose of an object manipulated by a multifingered hand in a realistic environment. The system uses the least-squares method to estimate the pose, on the assumption that the approximate initial pose and geometric shapes of the object and fingertips are known. 3D measurement of features on the surface of the object is achieved by visual tracking with stereo camera using a template matching method. The primary features used for visual tracking are distinguishable texture patterns on the object surface. In complex environments, visual tracking can be failed due to the various occlusion. The system solves the occlusion problem by detecting the occlusion and using contact information of fingertips with the 3D visual information. Actual implementation of the system is explained together with results of experiments about the stability of tracking, the accuracy of estimation, and the processing time of the system.

This paper describes the interframe coding system (TRIDEC 1.5) used for NTSC color television signal transmission at a 1.5 Mbit/s rate. TRIDEC 1.5 is developed with the intention of making video teleconferencing service more economical. The system utilizes the following highly efficient coding techniques: 1) interframe combinational difference coding 2) temporal subsample coding 3) noise reduction 4) demand refreshing to protect against channel errors, which makes periodic forced refreshing unnecessary. In addition, new coding parameter control methods have been devised to prevent buffer memory overflow. The subjective evaluation test results make it clear that the encoded picture quality is good enough for teleconferencing use.

A new digital method for separation and reconstruction of NTSC color TV signals is described. Digital conversion between an NTSC signal and its baseband component signals is performed at a sampling rate of(12/5)f_{sc} \simeq 8.59MHz (fsc: the color subcarrier frequency), which is lower than the conventionally used3f_{sc}or4f_{sc}sampling rate. Since this lowered sampling rate satisfies the Nyquist condition for NTSC signals, the proposed digital method can provide an effective technique for the component coding of NTSC signals. Simulation results have shown that, with this method, no visible picture quality degradations can be observed for either the color bar signal or SMPTE Pictures.