ubuntu16.04安装ROS或者Autoware进行到rosdep update时出现错误，如ERROR: unable to process source ...

错误描述1：

wsy@wsy-2019:~/autoware.ai$ rosdep update
reading in sources list data from /etc/ros/rosdep/sources.list.d
ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml]:
(https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml)
ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/base.yaml]:
(https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/base.yaml)
ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/python.yaml]:
(https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/python.yaml)
ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/ruby.yaml]:
(https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/ruby.yaml)
ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/releases/fuerte.yaml]:
Failed to download target platform data for gbpdistro:

Query rosdistro index https://raw.githubusercontent.com/ros/rosdistro/master/index-v4.yaml
ERROR: error loading sources list:
(https://raw.githubusercontent.com/ros/rosdistro/master/index-v4.yaml)>
xag@xag-2019:~/autoware.ai$ rosdep update
reading in sources list data from /etc/ros/rosdep/sources.list.d
ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml]:
(https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/osx-homebrew.yaml)
ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/base.yaml]:
(https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/base.yaml)
ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/python.yaml]:
(https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/python.yaml)
ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/ruby.yaml]:
(https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/ruby.yaml)
ERROR: unable to process source [https://raw.githubusercontent.com/ros/rosdistro/master/releases/fuerte.yaml]:
Failed to download target platform data for gbpdistro:

Query rosdistro index https://raw.githubusercontent.com/ros/rosdistro/master/index-v4.yaml
ERROR: error loading sources list:
(https://raw.githubusercontent.com/ros/rosdistro/master/index-v4.yaml)>

解决办法：

sudo gedit /etc/resolv.conf

将原有的nameserver这一行注释，并添加以下两行：

nameserver 8.8.8.8 #google域名服务器

nameserver 8.8.4.4 #google域名服务器

保存退出，执行

sudo  apt-get update

再执行

rosdep update

出现：

然后就解决了！

2、错误描述：

wsy@wsy:~$ sudo rosdep init
ERROR: default sources list file already exists:
/etc/ros/rosdep/sources.list.d/20-default.list
Please delete if you wish to re-initialize

解决办法：

执行以下命令，删除已经存在的初始化文件：

sudo rm /etc/ros/rosdep/sources.list.d/20-default.list

然后再重新运行

sudo rosdep init

然后问题就解决了。

借鉴：https://blog.csdn.net/mrh1714348719/article/details/103803110