Demonstration Experiment of Advanced Inter-Radar Interference Suppression Method for X-Band Weather Radar Network in Japan

In order to mitigate flood damages caused by torrential rainfall or tornados, the fast and precise detection of severe weather signs is very important. It would be effective to increase the number of X-band multi-parameter phased-array weather radars (MP-PAWR), which can observe rapid volume scan up to a range of 80 km in less than 60 seconds. To achieve rapid observation, MP-PAWR is transmitted as fan beams and received as pencil multi-beams formed with DBF (Digital Beam Forming). On the other hand, the frequency resource allocated for the additional radars may be exhausted. In addition, unlike the conventional parabolic weather radars, the interference to the other radars by the fan beam type MP-PAWR are likely to be increased.

From 2018 to 2021, the Japan's Ministry of Internal Affairs and Communications (MIC) conducted R&D for the weather radar signal processing to improve the efficiency of spectrum utilization. Toshiba participated in this program and developed the advanced interference suppression technique, which utilized the pulse information of interfering radars to accurately detect and suppress interference. In this work, the effectiveness of the proposed interference suppression method will be shown based on the result of the demonstration experiment using the MP-PAWR and X band parabolic weather radar.

Figure 1 shows the correlation coefficient calculated from the data acquired in the demonstration experiment in which the parabolic weather radar observed weather echoes and interference from the MP-PAWR. Compared with the correlation coefficient of weather echoes (b) and that by proposed method (d), it is confirmed that the proposed method can be suppressed interference appropriately. Next, focusing on the boxplots (e), the estimation result by the proposed method is similar to those of weather echoes without interference. For example, comparing by median values, the value of the conventional method (c) is 7.3% lower than that of weather echoes (b), however the differential rate between the proposed method(d) and (b) is only less than 1%.

Figure1:https://drive.google.com/drive/folders/1nvwoosUJo9dkgdIrhU5_QGS_zC2WL77I