ELECTRONICS UPDATE: 5G Interference with GPS?
The Us-built Global Positioning System revolutionized navigation in 1983 when it became available for civilian use, ushering in an era of pinpoint-level positional accuracy. While the benefits of this technology are myriad, what would happen if another technology started transmitting on frequency bands that interfere with the accuracy of GPS? According to a Boatu.s. press release dated June 25, 2020, this scenario could be about to begin unfurling. Satellite-communications company Ligado Networks (née Lightsquared) recently received permission from the Federal Communications Commission to begin constructing and operating a terrestrial-based industrial 5G network that will use a slice of the L-band frequency (1 to 2 gigahertz). Boatu.s. and the Keep GPS Working Coalition (of which Boatu.s. is a founding member) believe that Ligado Networks’ 5G wireless network will increase interference with GPS frequencies (1176.45 to 1575.42 megahertz) as their system comes online, potentially putting boaters’ and other GPS users’ safety at risk, and there is a group appealing the FCC’S decision.
“L-band communications, until now, have been reserved for orbiting satellites only and not terrestrial use,” says Jim Mcgowan, Raymarine’s Americas marketing manager. “The fear is their ground-based signals, though low-power, will be strong enough to cause interference with GPS and other satellite systems, whose signals are far weaker by the time they get back to Earth.”
While this is disconcerting, Mcgowan was quick to add that GPS hardware manufacturers are constantly building better mousetraps. “With each new generation of GPS receiver, tremendous improvements have been made to receiver sensitivity, interference rejection and anti-spoofing,” he says. “But as good as those improvements are, they’re all for naught if the GPS signals are drowned out before they get back to [the] ocean.”
Still, other GPS hardware manufacturers are less than convinced of the interference issue posed by Ligado Networks. “We’re not currently aware of a situation in which the land-based industrial 5G wireless network will negatively impact GPS, but we will continue to monitor the situation closely, in the interest of our customers,” says Stephen Thomas, Simrad’s senior vice president.
As of this writing, it’s unclear as to how much effect—if any—ligado Networks’ 5G wireless network will have on GPS performance, or when, but it’s important to note that the FCC made its decision to approve this network on April 22, 2020, while the US was wrestling with the opening salvos of the COVID-19 pandemic. Moreover, the Keep GPS Working Coalition (keepgpsworking.com) believes that the FCC ignored germane evidence regarding this critical issue. Finally, it bears noting that the FCC suspended consideration of Lightsquared’s proposed 4G LTE network in 2010, citing “unresolved concerns” over interference with GPS signals. As a result, Lightsquared filed for bankruptcy in 2010, however Ligado reemerged in May 2020 with $100 million in fresh funding from unnamed sources.