Using sudo apt get install ROS melodic TEB local planner
to install the software, this error is reported, and the solution found can not be used
later, it is found that there is this file in the mirror source, but the previous one is all right, and the suffix of the upload date is wrong, which leads to the failure to find the installed package
after searching, it is found that there is a problem with DNS resolution

Solution:
change DNS first https://note.qidong.name/2020/05/resolvconf/
Modify the/etc/resolv.conf file, add 202.106.0.20
this is from Beijing Unicom, and then execute sudo apt get update
to get the result

W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://mirrors.tuna.tsinghua.edu.cn/ros/ubuntu bionic Release: The following signatures were invalid: EXPKEYSIG F42ED6FBAB17C654 Open Robotics <[email protected]>
W: Failed to fetch http://mirrors.tuna.tsinghua.edu.cn/ros/ubuntu/dists/bionic/Release.gpg  The following signatures were invalid: EXPKEYSIG F42ED6FBAB17C654 Open Robotics <[email protected]>
W: Some index files failed to download. They have been ignored, or old ones used instead.

Such an error report
execute sudo apt key adv — KeyServer keyserver.ubuntu.com — recv keys f42ed6fbab17c654
the following key is the key on the error report, just copy it

Then execute sudo apt get update
and finally sudo apt get install ROS melody TEB local planner
successfully!