LightSquared lashes back at GPS industry

LightSquared has dropped its conciliatory tone with its critics in the GPS industry, choosing instead to go on the offensive. Preempting an FCC report that found massive interference to GPS receivers from its proposed long-term evolution (LTE) network, LightSquared issued a statement accusing GPS device manufacturers of rebuffing LightSquared’s efforts to cooperate on finding a workable fix to the interference problem (Briefing Room: LightSquared submits nationwide spectrum plan to the FCC). And in an attempt to turn the tables on the GPS industry, LightSquared claimed that GPS devices were the source of the interference problems, not LightSquared’s network. (CP: Why the GPS industry needs to work with LightSquared)

GPS device test results, which were also filed at the FCC today, show unequivocally that the interference is caused by the GPS device manufacturer’s decision over the last eight years to design products that depend on using spectrum assigned to other FCC licensees.

Now LightSquared is stepping forward to help resolve the problem. In contrast, the GPS device manufacturers, unlike relevant government agencies, have been largely uninterested in finding a win-win solution. Rather, their only answer to a problem of their own making is to demand that the government simply block LightSquared from using the company’s own spectrum to roll out the first wholesale-only wireless broadband network for the entire nation – an economic benefit worth as much as $120 billion to consumers. This is a problem that the GPS industry could have avoided by equipping their devices over the last several years with filters that cost as little as five cents each.

LightSquared is referring to the tendency of GPS receivers to collect signals from well outside the designated GPS band. When the L-band was designated only for satellite use, this wasn’t an issue, as satellite signals are at such low power they wouldn’t wash out GPS. But LightSquared’s proposed terrestrial LTE network would introduce a tremendous spike in transmit power, which a GPS receiver without filters can’t ignore. The problem is exacerbated as devices move into the high-precision range as more sensitive receivers venture further into the LightSquared’s L-band frequencies. That’s why LightSquared’s proposal to create an ad hoc guard band and only use its lower band spectrum would have still caused problems with sensitive avionics and surveying gear (CP: LightSquared proposes swapping half its network for FCC approval).

Despite the barbed language, LightSquared CEO Sanjiv Ahuja said that the carrier is fully committed to working with the GPS industry to find a solution to remaining interference problems even after its compromise plan to deploy only half of its proposed plan is implemented. LightSquared also stated that the GPS industry has an obligation to cooperate since it “built a business by piggy-backing on the federal government’s GPS network without any investment in infrastructure or spectrum.”

“This issue will be resolved by good data, smart engineers and good faith problem solving dialog,” Ahuja said in a statement. “The end-result will be continuity for the reliable and safe GPS system we have come to depend on along with a new high speed wireless network that will provide huge benefits to consumer.”

The Coalition to Save Our GPS, a group of location and navigation equipment manufacturers that has organized the defense of the GPS band, didn’t respond directly to LightSquared’s new accusations, but it had plenty to say that about the FCC technical working group final report issued today that roundly pans any chance of LightSquared implementing a network using today’s technology without causing massive problems for mission-critical GPS applications. LightSquared had originally hoped that the working group--consisting of representatives from government agencies, GPS equipment makers, telecom operators and LightSquared itself—would prove its claims that interference was a manageable issue. Instead, the report makes the opposite case, identifying not only unacceptable interference in every category but questioning whether any of LightSquared’s proposed fixes would have any impact.

Save Our GPS certainly felt vindicated by the report. Coalition founding member and Trimble general counsel Jim Kirkland issued this statement:

"LightSquared has been saying since November 2010 that interference to GPS is manageable and technical fixes are available. With the filing of the FCC working group report, all the studies are now in and provide consistent and overwhelming evidence that LightSquared's proposed operations would cause massive interference to every type of GPS device, even devices in outer space. There is no current, existing technology that solves this interference, only unproven claims of hypothetical future fixes. Yet LightSquared still says the same things it said last fall – interference can be "mitigated" and technical solutions will be available in the future. LightSquared has no credibility left, and no one – except those with an economic stake in the outcome – has come forward to support their technical claims.

“At this point, it could not be clearer that LightSquared gambled on the outcome of these technical tests and lost. The FCC, unfortunately, took LightSquared at its word and pushed for extremely fast track consideration of its proposals. This process has consumed millions of dollars and tens of thousands of hours of the employees of the 42 companies and 15 government agencies and other organizations participating in the test process, as well as substantial government resources in a time of budget cuts.“

The working group report itself reads like a 300 page argument (The full report can be accessed on the FCC filing page under TWG final report). Many of the executive summaries are split into “GPS Industry” and “LightSquared” perspectives, which not only contradict one another over interpretation of the testing data, but in many cases directly criticize the other camp’s conclusions. In general, the report found evidence of substantial interference in every test case from high-precision GPS and avionics to the assisted GPS embedded in most smartphones—conclusions that in may cases LightSquared was forced to agree with. Take this one excerpt from the Aviation sub-team:

Based on the approach outlined above, the Aviation Sub-team concluded that all three phases of the currently proposed LightSquared deployment plan are incompatible with aviation GPS operations absent significant mitigation, and would result in a complete loss of GPS operations below 2000 feet above ground level (AGL) over a large radius from the metro deployment center. For the originally defined LightSquared spectrum deployment scenarios, GPS-based operations are expected to be unavailable over entire regions of the country at any normal operational aircraft altitude.

In that instance LightSquared conceded to those conclusions (though in other categories it did not), but it disagreed strongly with aviation representatives in the group over whether a filter retrofit on avionics gear could solve the problem within a reasonable timeframe.

In other cases, LightSquared not only disagreed with GPS representatives about potential solutions but on how the test data was interpreted. GPS representatives in the general location/navigation sub-group found that LightSquared’s network interfered with all tested devices in its originally proposed network configuration and with 20 out of 29 devices under LightSquared proposed compromise configuration utilizing only lower L-band spectrum. LightSquared and the GPS industry, however, had different definitions of what constituted harmful interference to those receivers. According to LightSquared, the GPS members were using “worst-case” propagation models rather than “probabilistic” propagation models. LightSquared thus concluded: "This analysis shows that 13 devices passed when tested against upper channel configurations and all 29 devices passed when tested against the lower 10 MHz channel configuration."

With such fundamental disagreement over things like the definition of harmful interference, the two sides are unlikely to come to any kind of meaningful consensus. In fact, rather than tone down the public rhetoric from the GPS industry criticizing LightSquared as technical reports are apt to do, the Working Group's final report amplifies that criticism. In many cases, the text states clearly that LightSquared should simply exit the L-band.