ubutnu下apt安装时报错：The following signatures were invalid: KEYEXPIRED 1622248854

ubuntu@burger:~$ sudo apt update

Hit:1 http://ppa.launchpad.net/ubunt ... buntu xenial InRelease

Hit:2 http://ppa.launchpad.net/ubunt ... buntu xenial InRelease                                                 

Hit:3 http://ports.ubuntu.com xenial InRelease                                

Get:4 http://ports.ubuntu.com xenial-updates InRelease [109 kB]

Hit:5 https://packages.ubiquityrobot ... quity xenial InRelease

Get:6 http://packages.ros.org/ros/ubuntu xenial InRelease [4,678 B]                

Err:6 http://packages.ros.org/ros/ubuntu xenial InRelease                          

  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY F42ED6FBAB17C654

Get:7 http://ports.ubuntu.com xenial-security InRelease [109 kB]                                                                                    

Get:8 http://ports.ubuntu.com xenial-backports InRelease [107 kB]                                                                                   

Get:9 http://ports.ubuntu.com xenial-updates/main armhf Packages [783 kB]                                                                           

Get:10 http://ports.ubuntu.com xenial-updates/universe armhf Packages [683 kB]                                                                      

Fetched 1,796 kB in 3min 46s (7,916 B/s)                                                                                                            

Reading package lists... Done

Building dependency tree       

Reading state information... Done

335 packages can be upgraded. Run 'apt list --upgradable' to see them.

W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://packages.ros.org/ros/ubuntu xenial InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY F42ED6FBAB17C654

W: Failed to fetch http://packages.ros.org/ros/ub ... lease  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY F42ED6FBAB17C654

W: Some index files failed to download. They have been ignored, or old ones used instead.