instalation 2的问题"E:找不到软件包ROS -foxy-foxy“

Question

我尝试在ubuntu的focal (20.04)上安装ROS 2。

I went along with this instruction，但在实现此命令后：

sudo apt update

我遇到了这个问题：

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.

在那之后：sudo apt install ros-foxy-desktop

我明白了：

Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package ros-foxy-desktop

Answer 1

我修好了。基本上，我添加了新的存储库密钥并删除了旧密钥。这对我很有效：

https://answers.ros.org/question/379190/apt-update-signatures-were-invalid-f42ed6fbab17c654/