Hi, My robot is Pioneer 3, but I have not the laser sensor, for that Hokuyo and SICK sensors are way out of reach for us. So I want to use sonar to make SLAM and then make navigation. And I want to find an existed package to achieve our goal, but it seems that it almost pretty much requires the usage of a laser for SLAM and navigation. So how can I begin my work to use sonar to achieve SLAM and navigation. Is there any examples to help me? By the way, I have studyed the amcl package several times, But I still don't know where Publisher the topic "scan" or "base_scan", that's to say, where the laser data comes from? Any help will be appreciated! Thanks in advanced! jolin