The House Science, Space and Technology Committee will join the ranks of those looking into LightSquared’s plans to implement a mobile broadband communications system that could interfere with Global Positioning System (GPS) navigation satellite receivers. It has scheduled a hearing for August 3.
LightSquared plans to offer “4G” mobile broadband services using a hybrid satellite-terrestrial system. Through predecessor companies, it has offered mobile satellite services since 1996 using the Canadian-licensed MSAT-1 and U.S. licensed MSAT-2 satellites. SkyTerra-1, launched last fall, is a replacement for MSAT-2 and the company wants to use it to expand its mobile broadband communications services in conjunction with a terrestrial network of 40,000 cellular base stations – formally called an “Ancillary Terrestrial Component” or ATC.
The Federal Communications Commission (FCC) regulates use of radio frequencies by the private sector and its rules for this type of service require the satellites and ATC to work together to provide an “integrated service.” The purpose of permitting ATCs was only to fill gaps in satellite service in places where the satellite signals cannot penetrate or where there are too many users. LiqhtSquared wants the FCC to waive the integrated service requirement so it can offer services using its terrestrial component alone instead of necessarily in conjunction with its satellite signals.
The FCC granted LightSquared the waiver in January, but on the condition that LightSquared resolve questions about whether its terrestrial system would interfere with GPS receivers. The FCC directed the company to form an industry “technical working group” (TWG) with representatives of the GPS community to conduct tests and submit a report and LightSquared’s recommendation by June 15.
The prospect of the ATC terrestrial network has caused great consternation among GPS users, particularly in the aviation sector. Studies by groups including the RTCA, which functions as an advisory group to the Federal Aviation Administration (FAA), and the interagency National Space-Based Positioning, Navigation and Timing (PNT) Executive Committee, showed that GPS interference was a significant problem.
The House Transportation and Infrastructure Committee held a hearing on June 23. When scheduled, it would have occurred after the industry TWG report was released, but at the last minute LightSquared requested a two-week delay in submitting the report, which the FCC granted. Thus the hearing was held before that report was out. With the exception of LightSquared itself, the witnesses at the hearing warned of near-calamitous consequences if LightSquared was allowed to proceed.
The day after the hearing, the House Appropriations Committee adopted an amendment to the FY2012 Financial Services Appropriations bill offered by Rep. Steve Austria (R-OH) and Rep. Kevin Yoder (R-KS) that would prohibit the FCC from spending funds to remove the conditions it placed on the license or to otherwise permit LightSquared to proceed until the FCC has resolved the GPS interference issues. The bill (H.R. 2434) has not yet passed the House.
The industry TWG released its report the following week. Like the other studies, it showed that interference is a problem. LightSquared, however, blamed the GPS industry, not its system. The company argues that the GPS receiver manufacturers did not properly design and build the receivers to protect them from picking up neighboring frequencies.
At issue are the L-band frequencies assigned to LightSquared by the FCC for downlinks from its satellite to ground stations, 1525-1559 MHz, which are also authorized for ATC. The company plans to use two 10 MHz-wide portions of that spectrum (1526-1536 MHz and 1545.2-1555.2 MHz) for the ATC. One of GPS’s frequency bands, L1, is at 1560-1610 MHz.
LightSquared’s report to the FCC based on the findings of the industry TWG agreed that transmissions in the top 10 MHz of its band definitely will interfere with GPS receivers, but the company insists that transmissions in the bottom 10 MHz will not interfere with 99 percent of GPS receivers, only with 1 percent used for specialized purposes. LightSquared’s recommendation is that it be allowed to proceed in the bottom 10 MHz of its band while coordinating and sharing the cost of underwriting “a workable solution” for the 1 percent of devices that would be affected. The company would delay using the top 10 MHz of its band while exploring options with the FCC and other government agencies. The RTCA report recommended that the company only be allowed to use the bottom 5 MHz of the band.
The FCC is requesting public comments on the industry TWG report and LightSquared’s recommendation. They are due July 30.
The House SS&T Committee has not released a list of witnesses for its hearing. The hearing’s title indicates only that it is looking at LightSquared’s impact on federal science activities.
Last Updated: Dec 05, 2011 6:14 pm ET