Inside GNSS Media & Research

MAY-JUN 2018

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20 Inside GNSS M A Y / J U N E 2 0 1 8 www.insidegnss.com areas. Macro cells comprise of a cell tower about 25 meters high with a cell radius of 0.25 to 1 kilometer. Urban micro cells were assumed to have 6-meter antennas and there could be one to three per macro cell. ey also looked at macro cells in rural areas. The yardstick for determining interference used in the Assessment is a greater than a 1 dB reduction in carrier-to- noise density ratio (CNR). Ligado has opposed the internation- ally accepted 1 dB standard, pushing instead for a degradation of user position information. As was found in previous studies the impact of the signals was the greatest on high precision receivers (HPRs). e maxi- mum power tolerable by an HPR was -41.9 EIRP (dBW) in the macro urban environment at a distance of 10 meters. e finding was very similar (-41.2 dBW) for the 10-meter micro urban environment. (See chart ES-1 above). e Assessment also found that the impacts of interference could, in some cases, be felt for miles. "e high precision category of receiver exceeds a 1 dB signal-to-noise density (C/N0 interference protection criteria at a distance beyond 14 km from the transmitter," the study team wrote. "When this occurs, the behavior of the GPS/GNSS receiver can become unpredictable in its ability to meet the accuracy, availability, and integrity requirements of its intend- ed application and a receiver in a mobile application may not be able to reacquire GPS positioning as the mobile application encounters multiple, closely-spaced emitters in an urban sce- nario. Furthermore, this category of receiver experiences loss of lock for low elevation GPS/GNSS satellites at distances up to 3 km with loss of lock on all satellites at approximately 1 km from the transmitter. "It is unclear how the results would relate to the current plans of LightSquared's successor as the firm is still working out its business model. Ligado has said it will forgo the origi- nal LightSquared plan of offering wholesale broadband ser- vices across the country and instead has proposed to provide private custom networks and connectivity for the Internet of ings. GAO: GPS Modernization Costs Remain Unclear A new watchdog report says the Air Force has yet to develop full cost estimates for the new ground system and user equipment essential for utilizing the expanded capabilities of the upcoming GPS III generation of satellites. The Government Accountably Office (GAO) said in its annual assessment of weapons systems for Congress that the Air Force is still developing a final budget number and schedule for the Next Generation Operational Control System (OCX). OCX is necessary for implementing the new military M-Code among other enhancements. Raytheon is the prime contractor for OCX, which is now expected to reach initial capability in April 2022, according to GAO. e program — as of November 2016 — was more than five years behind schedule and, at $5.57 billion (2018 dollars), 52 percent over its original development budget, the agency wrote. ere appears to be limited official information available to update those 15-month-old cost and schedule estimates. e Air Force is still reviewing the program and developing a new budget and timeline. is effort has been underway since June 2016 when the service declared a critical Nunn-McCurdy breach. e program faced automatic cancellation unless the Department of Defense (DoD) certified its need for the pro- gram and conducted a review of what caused the breach; the schedule and budget rebaselining is part of that effort. e Air Force has an "unapproved baseline," GAO reported, and "is using developmental funds to acquire the system." e Air Force told GAO the program now has a June 2021 acceptance date from prime contractor and "the Air Force has assessed 7 months of risk to meeting that date." e GPS program office also undertook a comprehensive review of the OCX program's schedule and cost according to GAO, which was to be completed in April 2018. is comprehensive review will inform completion of an independent cost estimate, which will in turn support completion of the system development review and approval of an acquisition program baseline. Inside GNSS learned last summer that the development cost for the program was expected to jump to around $6 billion. ere was also an expected slippage of some nine months due to "realized program technical risks" and the need to refresh out-of-date hardware and soware, according to the Air Force. As of press time Inside GNSS has not received responses to questions to Raytheon about the program and to the Air Force about the budget and schedule review. e Military GPS User Equipment (MGUE) program has a problem of a different kind. "The full cost and schedule for implementing military-code receiver cards across DoD remains unknown," reported GAO. The Pentagon had determined as of February 2017 that there were 716 weapon systems that would need the military- code receiver cards under development by the GPS program office and its three contractors: L-3 Technologies, Raytheon and Rockwell Collins. e GPS program is working under the first increment of the MGUE program to develop the cards with the goal of making them as interchangeable as possible with existing receiver cards while incorporating the new M-Code and other capabilities. The many weapon system programs using the cards will handle the actual purchasing and integration. GAO said, however, that the DoD has only identified $2.5 billion in partial costs associated with 28 of those 716 weapon systems — less than 4 percent. eir estimate was based on M-Code implementation plans submitted by the military servic- es, Missile Defense Agency, and Special Operations Command. ough Congress mandated in the National Defense Authori- zation Act for Fiscal Year 2011 that money not be spent to buy equipment without M-code capability aer fiscal year 2017, the technology for the cards is still immature. As a result, many programs are now operating under waivers. 360 DEGREES

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