这个错误表示在进行软件包签名验证时发生了问题。系统无法验证存储库的签名，因为缺少相关的公钥。为了解决这个问题，你可以尝试以下几种方法：

导入公钥：使用以下命令导入缺少的公钥。将 [KEY_ID] 替换为错误消息中提到的实际密钥ID。

运行命令后，系统将尝试从指定的密钥服务器下载并导入公钥。然后，你可以再次尝试更新存储库并检查问题是否解决。

使用软件源管理工具：如果你使用的是 Ubuntu，可以尝试使用 software-properties-common 包中的 add-apt-repository 命令来添加存储库。首先，确保你已安装该软件包：

然后，尝试添加存储库并更新：

这将尝试将存储库添加到系统中，并更新软件包列表。

检查网络连接：有时，网络连接问题可能导致密钥无法下载。确保你的系统可以访问密钥服务器和存储库。你可以尝试使用浏览器或 curl 命令访问 https://apt.kitware.com/ubuntu 确认网络连接是否正常。

如果以上方法没有解决问题，可能是由于存储库本身存在问题。在这种情况下，你可以考虑联系存储库的维护人员或寻求相关论坛或社区的帮助来获取更多支持和解决方案。

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

注意，那个yaml源要用镜像

WARNING: ROS_PYTHON_VERSION is unset. Defaulting to 3 WARNING: The directory ‘/root/.cache/pip’ or its parent directory is not owned or is not writable by the current user. The cache has been disabled. Check the permissions and owner of that directory. If executing pip with sudo, you should use sudo’s -H flag. WARNING: The directory ‘/root/.cache/pip’ or its parent directory is not owned or is not writable by the current user. The cache has been disabled. Check the permissions and owner of that directory. If executing pip with sudo, you should use sudo’s -H flag. ERROR: the following packages/stacks could not have their rosdep keys resolved to system dependencies: python_orocos_kdl_vendor: [python3-pykdl] defined as “not available” for OS version [bionic] ignition_math6_vendor: No definition of [ignition-math6] for OS version [bionic] rti_connext_dds_cmake_module: No definition of [rti-connext-dds-6.0.1] for OS version [bionic] ignition_cmake2_vendor: No definition of [ignition-cmake2] for OS version [bionic]

这个是因为

参考安装指南： https://zhuanlan.zhihu.com/p/364745633 https://blog.csdn.net/fanshuaifang/article/details/114399792

https://blog.csdn.net/fanshuaifang/article/details/114399792#:~:text=2%20Foxy%E9%9C%80%E8%A6%81%E4%BB%A5%E4%B8%8B%E6%AD%A5%E9%AA%A4%EF%BC%9A%201.%20%E7%A1%AE%E8%AE%A4%E4%BD%A0%E7%9A%84%20Ubuntu%20%E7%B3%BB%E7%BB%9F%E6%98%AF18.04%E7%89%88%E6%9C%AC%EF%BC%8C%E5%90%A6%E5%88%99%E9%9C%80%E8%A6%81%E5%85%88%E5%8D%87%E7%BA%A7%E4%BD%A0%E7%9A%84%E7%B3%BB%E7%BB%9F%E3%80%82%202.%20%E9%85%8D%E7%BD%AE,add%20-%20%60%60%60%204.%20%E6%9B%B4%E6%96%B0apt%E6%BA%90%E5%B9%B6%20%E5%AE%89%E8%A3%85ROS%202%20Foxy%E3%80%82 安装成功。