This does something not possible with gps, or AP or essid detection.

There may be many APs within an organization. Detecting presence within the organization therefore may require knowing every AP's mac address and/or essid as that would not be feasable.

What you could depend on however, is the presence of a specific host (by ip or hostname) that is able to reply to pings or http gets. you would use a host on your internal lan, by its internal IP address, and if the http get included [companyname] or other text that would normally appear on that internal only server, you would know absolutely, that you are within wifi range of your company.

You could also use the mac address of the default gateway given during dhcp. That would be less likely to work in large organizations, but wouldn't require knowing a reliable other host to detect on the network.