Pingviewer

We built an Unmanned Surface Vehicle using Pixhawk and Ping Sonar. The ping sonar will send the signal and generate my image /data through ping_viewer. However, my Pingviewer shows only a blank screen with "0.00m Confidence :0%.
Please, what am I doing wrong? What am I supposed to do?
All suggestions are welcomed and appreciated.

No files, tests, or code entry points are named. Start by reproducing the blank Ping Viewer display with the reported Pixhawk and Ping Sonar setup, then collect connection or data details that distinguish a hardware, signal, or viewer problem. Done would require identifying the cause and confirming that sonar data appears instead of 0.00m and 0% confidence.

Written by the indexing model from the issue text.