If we're to believe a new pressure group called Coalition to Save our GPS, it won't be long until we find out. The group consisting of GPS manufacturers, airline trade organizations, and other concerned parties, claims that a is on the brink of breaking Global Positioning Systems for the population at large, including emergency responders such as ambulances and police.

The problem relates to the frequencies a startup called LightSquared intends to use for its 4G LTE phone service. Earlier this year to operate in the frequency range of 1525 to 1559MHz. GPS operates in the neighboring 1559-1610MHz band and--depending on who you speak to--it's all a little too close for comfort, not least because cell phone signals from towers are an order of magnitude stronger than GPS signals.

A few weeks ago GPS device manufacturer Garmin . It caused havoc for several Garmin products. An aviation device lost its GPS fix at just under 14 miles away from the transmitter and was totally jammed five and a half miles away. One of Garmin's most popular consumer devices lost its fix just over half a mile away.

Scary. The coalition points out that LightSquared plans to built up to 40,000 ground stations, potentially creating an equivalent number of GPS dead spots miles in diameter.

In response, LightSquared points out that the Garmin tests were "not made under appropriate circumstances" and that "tests must be conducted in the proper band and with the right filters." They add that they're running their own tests, supported by the government.