Japan Geoscience Union Meeting 2018

Presentation information

[JJ] Oral

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS19] Atmospheric electricity

Tue. May 22, 2018 1:45 PM - 3:15 PM 201A (2F International Conference Hall, Makuhari Messe)

convener:Yasuhide Hobara(Graduate School of Information and Engineering Department of Communication Engineering and Informatics, The University of Electro-Communications), Masashi Kamogawa(Department of Physics, Tokyo Gakugei University), Chairperson:Morimoto Takeshi, KAMOGAWA Masashi(Department of Physics, Tokyo Gakugei University)

3:00 PM - 3:15 PM

[MIS19-06] Capon beamforming with diagonal loading for X-band phased array weather radar

Youichi Hayashi1, *Hiroshi Kikuchi1, Tomoaki Mega1, Eiichi Yoshikawa3, Tomoo Ushio1, Koji Nishimura2 (1.Tokyo Metropolitan University, 2.National Institute of Polar Research, 3.Japan Aerospace Exploration Agency)

Keywords:Precipitation observations, Phased array radar

The X-band Phased Array Weather Radar (PAWR) at Osaka University has performed three-dimensional precipitation observations in less than 30 seconds [1]. The observation range is 60 km. As a transmitted waves of the radar, a fan-shaped transmission beam is used, with a narrow beamwidth (1.2 [deg]) in azimuth and a wider beamwidth (5.0 [deg]) in elevation. In elevation angles, Fourier beamforming method is used for electronic scanning, with 128 antenna elements. The fan beam is useful to support rapid scanning. However, the received signals tend to be affected by the influence of ground clutter. The PAWR is intended to operate in urban areas, where many tall buildings exist. Consequently, clutter echoes have much influence, even at high elevations.

The PAWR is developed on the premise of being applied to advanced digital beamforming (DBF) is used for electronic scanning in elevation methods, such as the Capon beamformers [2,3]. In this paper, we applied the Capon beamforming with diagonal loading for the X-band phased array weather radar.

To discuss the impact of the clutter reduction using the Capon beamforming with diagonal loading (CPDL), the signals received by the 128 channels of the PAWR on July 1, 2016, 13:56:15 (JST) are used. The proposed correction procedure was shown to be capable of handling those errors in both domains (phase and amplitude). From the comparison between the results of the different DBF methods (FR and CPDL), FR overestimated the received power from low elevation angles (0°–5°) to high elevation angles (10°-30°) because the beam pattern has the high sidelobe level. On the other hand, CPDL was shown to be very effective in mitigating the clutter at all elevation angles, because of its better suppression of the sidelobes at low elevation angles.

[1] F. Mizutani, M. Wada, T. Ushio, E. Yoshikawa, S. Satoh, and T. Iguchi, “Development of active phased array weather radar,” in 35th Conference on Radar Meteorology, Sept. 2011.

[2] J. Capon, “High resolution frequency-wavenumber spectrum analysis,” Proc. IEEE, vol. 57, pp. 1408–1418, Aug. 1969.

[3] P. Stoica, Zhisong Wang and Jian Li, "Robust Capon beamforming," in IEEE Signal Processing Letters, vol. 10, no. 6, pp. 172-175, June 2003