【求助】Ubuntu16.04 + ROS kinetic 环境下Ti毫米波雷达数据的可视化、录制点云信息并生成pcd文件时时间戳一直为零要怎么办

我用的毫米波雷达是TI公司的IWR1642BOOST，利用Rviz得到如下点云图像：

我想要把点云信息导出为pcd文件，参考ros官网教程可用下列命令：
rosrun pcl_ros pointcloud_to_pcd input:=/mmWaveDataHdl/RScan
这个命令会生成多个以时间戳命名的pcd文件，但是我不知道为什么，我的点云数据时间戳一直为0，这导致每一帧生成的pcd文件都为0.pcd，后面生成的文件覆盖前面的文件，导致最后只保留了最后一帧的pcd文件，请问有人遇到过这个问题吗，应该怎样解决呢？
以下是输入上述命令后终端打印出的信息：

[ INFO] [1550473393.836839654]: Saving as binary PCD
[ INFO] [1550473393.840732820]: Listening for incoming data on topic /mmWaveDataHdl/RScan
[ INFO] [1550473394.074448795]: Received 29 data points in frame base_radar_link with the following fields: x y z intensity
[ INFO] [1550473394.074523061]: Data saved to 0.pcd
[ INFO] [1550473394.109396429]: Received 31 data points in frame base_radar_link with the following fields: x y z intensity
[ INFO] [1550473394.109472467]: Data saved to 0.pcd
[ INFO] [1550473394.139356596]: Received 31 data points in frame base_radar_link with the following fields: x y z intensity
[ INFO] [1550473394.139430036]: Data saved to 0.pcd
[ INFO] [1550473394.179684003]: Received 31 data points in frame base_radar_link with the following fields: x y z intensity