The authors have developed a digital beam forming dynamic imaging radar system, ”VirA.” It is a cutting-edge non-contact measurement technology for space-continuous vibration monitoring of buildings. In this research, the authors have presented the vibration monitoring method by conducting vibration measurements of an actual tall building. Experiments were performed to compare the performances of two time-synchronized radars and a conventional vibrometer. Frequency analysis was performed and the dominant frequencies were compared with those determined from the conventional vibrometer.
KEYWORDS: Cameras, Antennas, Interferometry, Signal processing, Image processing, Extremely high frequency, Receivers, Digital filtering, Data conversion, Signal to noise ratio
A proto-type passive millimeter-wave (MMW) camera with interferometric processing has been developed and
evaluated to confirm the feasibility of the interferometric MMW camera and to study the characteristics of MMW
images. This proto-type camera is comprised of the minimum configuration as an interferometric imager which
consists of two sets of a W-band receiver with a horn antenna, and a digital processing unit. The position of these two
antennas with W-band front-end moves on the precision linear slider in horizontal and vertical axis. The coherently
amplified two channel signals are digitized and processed in the hardware processor. The process is comprised of
correlation of all combination of each axis data, and integration to improve the signal to noise ratio. The integrated
data is processed to make an image by matched filter processing. The integration time is from 1mS to 10S depending
on required integration gain. The maximum synthesized antenna aperture size is 1m for horizontal axis and 50cm for
vertical axis. In this paper, the evaluation of the proto-type P-MMW camera is descried. After the evaluation, some
improvement was scheduled and conducted. Also, future plan for a real-time camera using this technique is presented .
This paper describes the experiment of the repeat pass interferometric SAR using Pi-SAR(L). The air-borne repeat-pass interferometric SAR is expected as an effective method to detect landslide or predict a volcano eruption. To obtain a high-quality interferometric image, it is necessary to make two flights on the same flight pass. In addition, since the antenna of the Pi-SAR(L) is secured to the aircraft, it is necessary to fly at the same drift angle to keep the observation direction same. We built a flight control system using an auto pilot which has been installed in the airplane. This navigation system measures position and altitude precisely with using a differential GPS, and the PC Navigator outputs a difference from the desired course to the auto pilot. Since the air density is thinner and the speed is higher than the landing situation, the gain of the control system is required to be adjusted during the repeat pass flight. The observation direction could be controlled to some extent by adjusting a drift angle with using a flight speed control. The repeat-pass flight was conducted in Japan for three days in late November. The flight was stable and the deviation was within a few meters for both horizontal and vertical direction even in the gusty condition. The SAR data were processed in time domain based on range Doppler algorism to make the complete motion compensation. Thus, the interferometric image processed after precise phase compensation is shown.
KEYWORDS: Antennas, Extremely high frequency, Cameras, Interferometry, Signal processing, Image processing, Receivers, Spatial resolution, Interferometers, Signal to noise ratio
A proto-type passive millimeter-wave (MMW) camera with interferometric processing has been developed. The
purpose is to confirm the feasibility of the interferometric MMW camera and to study the characteristics of MMW
images. In this paper, the principle and the feature of the interferometric MMW camera is described. Also, the
hardware configuration and the image processing algorithm are presented. This proto-type camera is comprised of the
minimum configuration as an interferometric imager which consists of two sets of a W-band front end with a horn
antenna, a receiver, and an A/D converter, a high-speed processing hardware, and a computer. The position of these two
antennas with W-band front-end moves on the precision linear slider in horizontal and vertical axis. The coherently
amplified two channel signals are digitized and processed in the hardware processor. The process is comprised of phase
error compensation, correlation of all combination of each axis data, and integration to improve the signal to noise ratio.
The computer input the integrated data to make an image by matched filter processing. The integration time is from
1mS to 10S depending on required integration gain. The maximum synthesized antenna aperture size is 1m for
horizontal axis and 50cm for vertical axis. Because it takes certain time to receive by the moving antennas, only the
targets without motion are imaged by this proto-type camera. The processed images will be shown. Also, future plan for a real-time camera using this technique is presented.
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