What ray_count is?

[pengzhi1998]

Thank you so much for your implementation of the ROS packages of hector sensors!

However, I'm confused about one argument for the sonar sensor: ray_count. What is it and what value should I give it if I want to use it as a single-beam echo sounder with a circular cone detection area?

Actually, if I set it to be 1, the sensor could only detect obstacles right in front of the sensor in the line but not inside the field of view.
Otherwise, if I set it to be a bigger value like 100, the return value will have some tremendous changes every now and then. For example, I make the robot static at one position in a static environment, the value will suddenly change from 4.6 to 10 (10 is the max range), and then change back. Meanwhile, the computer will be very slow which seems the 100 ray count sonar uses up a lot of computation ability.

Have you seen this before and do you know how to fix it? Thank you again for your project and your help! Look forward to your reply!