I try to install ROS 2 on ubuntu focal fosa (20.04).
I went along with this instruction, but after implementation this command:
sudo apt update
I got this problem:
Hit:1 http://ru.archive.ubuntu.com/ubuntu focal InRelease
Hit:2 http://ru.archive.ubuntu.com/ubuntu focal-updates InRelease
Hit:3 http://ru.archive.ubuntu.com/ubuntu focal-backports InRelease
Hit:4 http://download.opensuse.org/repositories/home:/Alexx2000/xUbuntu_20.04 InRelease
Hit:5 http://security.ubuntu.com/ubuntu focal-security InRelease
Hit:6 http://packages.osrfoundation.org/gazebo/ubuntu-stable focal InRelease
Get:7 http://packages.ros.org/ros2/ubuntu focal InRelease [4,670 B]
Err:7 http://packages.ros.org/ros2/ubuntu focal InRelease
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY F42ED6FBAB17C654
Reading package lists... Done
W: GPG error: http://packages.ros.org/ros2/ubuntu focal InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY F42ED6FBAB17C654
E: The repository 'http://packages.ros.org/ros2/ubuntu focal InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
And after that: sudo apt install ros-foxy-desktop
I got it:
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package ros-foxy-desktop