How to emit particles with the position of a Gaussian distribution by using "gps" command

Dear Jaeyoung Jeong,
Thanks for your reply, I tried the command as you mentioned, “/gps/pos/sigma_r”, the distribution is not Gaussion as you can see in the figure whatever I changed the parameters. In my opinion, this command
can only change the position of center of a circle rather than emit particles with a known distribution.

Best regards
Dis