Briefly, this is how I set it up with a TP Link WR802N router. The steps may vary for different routers and operating systems, and a familiarity with linux and networking will be required for different setups and troubleshooting.
The raspberry pi ethernet interface needs to be configured for dhcp. This is the default configuration on a raspbian jessie install. If you have a raspberry pi image configured for ardusub already, you will need to delete the 'ip=192.168.2.2' line from /boot/cmdline.txt that is described here.
Confirm that the raspberry pi is configured for dhcp and doesnt have a static ip address by looking at /etc/network/interfaces and make sure it looks like this:
pi@raspberrypi:~ $ cat /etc/network/interfaces
interfaces(5) file used by ifup(8) and ifdown(8)
Please note that this file is written to be used with dhcpcd
For static IP, consult /etc/dhcpcd.conf and 'man dhcpcd.conf'
Include files from /etc/network/interfaces.d:
iface lo inet loopback
iface eth0 inet manual
iface wlan0 inet manual
iface wlan1 inet manual
You will need to get the hardware mac address of the ethernet interface of the raspberry pi. Type 'ifconfig eth0' in a terminal on the pi, the hardware address will be listed in the output.
pi@raspberrypi:~ $ ifconfig eth0
eth0 Link encap:Ethernet HWaddr b8:27:eb:34:ff:9d
inet addr:192.168.0.20 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::bd2e:7045:3cd6:b30/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:20765 errors:0 dropped:11 overruns:0 frame:0
TX packets:11819978 errors:0 dropped:0 overruns:0 carrier:0
RX bytes:6763462 (6.4 MiB) TX bytes:3077012574 (2.8 GiB)
Next, sign into the router by connecting to it's wireless network, and typing 192.168.0.1 in a browser address bar. Configure the router operation mode for 'access point'.
You will need to sign back in to the router at 192.168.0.254 now.
Configure the router to assign specific dhcp ip addresses for your raspberry pi and your computer.
For the raspberry pi, use the mac address obtained above, and whatever ip you want. For your computer, you will need to get the mac address of the wifi interface, and do the same thing.
If you used different ip addresses than were previously configured for the direct wired connection, you will need to change the addresses in the mavproxy and video launch scripts.
Now you connect to the raspberry pi wirelessly by signing in to the router's wireless network from your computer.
After configuring for this setup, a direct wired ethernet connection will no longer work.