我正在尝试安装ros-opencv3和ros-rosserial-arduino。但是当我运行命令时sudo apt-get install ros-kinetic-rosserial-arduino，出现此错误：
E: dpkg was interrupted, you must manually run 'sudo dpkg --configure -a' to correct the problem.
我一运行这个命令，它就停在中间，并出现以下错误：
Downloading kernel sources...
Reading package lists...
Picking 'linux-signed-hwe' as source package instead of 'linux-image-4.15.0-46-generic'
Need to get 12,3 kB of source archives.
Get:1 http://de.archive.ubuntu.com/ubuntu xenial-updates/main linux-signed-hwe 4.15.0-48.51~16.04.1 (dsc) [1.829 B]
Get:2 http://de.archive.ubuntu.com/ubuntu xenial-updates/main linux-signed-hwe 4.15.0-48.51~16.04.1 (tar) [10,4 kB]
gpgv: Signature made Fr 05 Apr 2019 13:57:42 CEST using RSA key ID 70E1162B
gpgv: Can't check signature: public key not found
dpkg-source: warning: failed to verify signature on ./linux-signed-hwe_4.15.0-48.51~16.04.1.dsc
dpkg-source: info: extracting linux-signed-hwe in linux-signed-hwe-4.15.0
dpkg-source: info: unpacking linux-signed-hwe_4.15.0-48.51~16.04.1.tar.xz
WFetched 12,3 kB in 0s (34,0 kB/s)
: Can't drop privileges for downloading as file 'linux-signed-hwe_4.15.0-48.51~16.04.1.dsc' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)
grep: drivers/media/usb/uvc/uvc_driver.c: No such file or directory
INFO: No Intel RealSense(TM) cameras are currently supported.
Patching uvcvideo sources...
can't find file to patch at input line 5
Perhaps you used the wrong -p or --strip option?
这是什么问题？我该如何解决？