The changing patterns of magnetic fields created a unique signature at each point near the transmitter.
Low-frequency magnetic fields penetrated the ground and other solid objects more deeply than radio could have and provided a good depth metric via predictable changes in field intensity.
The result was the ability to "triangulate" the position of a sensor using only one antenna and no triangulation at all.
"Our technology can work out your position in three dimensions from a single transmitter. It can even tell you which way your device is facing," Markham told Wired.
Seeing an opportunity to move out of badgers and into location services, Markham and Trigoni took their system to Isis Innovation, a company owned by Oxford University whose job it is to commercialize scientific findings generated there.
The two are looking for 1.7 million pounds in seed capital to fund their startup, OneTriax, which is working on a version of the receiver that would run on Android.
Smart phones already have magnetometers and electronic compasses they use to orient the screen and locate cell-phone towers.
With slightly more processing power and greater sensitivity, those sensors could also pick up enough magnetic data to be used as a backup location system when line-of-sight GPS radio waves just won't cut it.
Making it work will require an advance in signal processing, but not a huge leap. Badger-net pickups rely on a signal with more information in it than a typical GPS radio signal, so reception will still be a challenge, Markham said.
The two have already developed the software to process it, however, and are working on ways to improve its accuracy to less than the 30cm give or take the Badger-net was able to achieve.
Within four years, Markham predicts, smartphones will be manufactured with his and Trigoni's underground GPS capability.
Then the only problems will be extending all those GPS networks with magnetic broadcasting stations, figuring out how to hand responsibility for location from one to the other as the user's location changes and deciding whether or not they'll have to pay the badgers a royalty.
"We think it's achievable," he told Wired.
Read more of Kevin Fogarty's CoreIT blog and follow the latest IT news at ITworld. Follow Kevin on Twitter at @KevinFogarty. For the latest IT news, analysis and how-tos, follow ITworld on Twitter and Facebook.