You're overground. There's poor GPS signal quality (the GPS receiver on the bus is better than that on your phone).
Would it not be good to still know where you are, on google maps etc?
This is a C++ application which can be installed on the mini computer which handles the GPS location of the bus and updates the passenger information. It uses the "gpspipe" daemon to relay the bus's location over a wireless network.
What if you aren't connected to a Wi-Fi network?
Why not create a hidden one, with the standardized name ".location". When no gps location is available your mobile device will try to connect to a web page "location.html" which is available on the gateway device.
This protocol has been submitted to the Internet task force and will hopefully become a standard.
Rob Brew (email@example.com).