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Global Positioning System Precision Encrypted (Y) Code Approach/Landing at Civil Airfields
Navy SBIR 2012.1 - Topic N121-030 NAVAIR - Ms. Donna Moore - [email protected] Opens: December 12, 2011 - Closes: January 11, 2012 N121-030 TITLE: Global Positioning System Precision Encrypted (Y) Code Approach/Landing at Civil Airfields TECHNOLOGY AREAS: Air Platform RESTRICTION ON PERFORMANCE BY FOREIGN CITIZENS (i.e., those holding non-U.S. Passports): This topic is "ITAR Restricted". The information and materials provided pursuant to or resulting from this topic are restricted under the International Traffic in Arms Regulations (ITAR), 22 CFR Parts 120 - 130, which control the export of defense-related material and services, including the export of sensitive technical data. Foreign Citizens may perform work under an award resulting from this topic only if they hold the "Permanent Resident Card", or are designated as "Protected Individuals" as defined by 8 U.S.C. 1324b(a)(3). If a proposal for this topic contains participation by a foreign citizen who is not in one of the above two categories, the proposal will be rejected. OBJECTIVE: Develop and incorporate the capability, on board military aircraft, to conduct an approach to near Category I minima utilizing Precision Encrypted Y Code (P(Y) available on both the L1 & L2 signals from the Global Positioning System (GPS) satellites. Desired solution would be independent of ground augmentation. DESCRIPTION: Military aircraft require the ability to divert to airfields in cases of emergency without having to rely on a unique set of landing system infrastructure. The current civilian GPS based landing systems, Space Based Augmentation Systems (SBAS) and Ground Based Augmentation Systems (GBAS), have limited areas of coverage and utilize Coarse Acquisition (C/A) code. Military aircraft have been directed to utilize P(Y) Code and reduce reliance upon the civil available C/A code. Use of P(Y) code only would prevent them from being able to land at civilian airfields based upon current technology. Even if SBAS and GBAS were the solution set for military aircraft civil divert capability, the current GBAS and SBAS infrastructure and resulting areas of coverage do not provide for a true 'world-wide divert' capability to all airfields. In order for US military aircraft to fly a precision approach to support all-weather operations, a vertical protection level [5] of 35 meters, and a horizontal protection level [5] of 40 meters are required. In addition, vertical accuracy required is 6 Meters, and horizontal accuracy required is 16 Meters. In practicality, this level of protection and accuracy affords aviators the ability to fly an approach in bad weather down near 200 ft above ground in 1/2 sm visibility (near Category I minima). A solution which requires the least modification to existing aircraft, preferably software modifications only, are preferred, but all solutions will be considered. The intent of the improvements made to the processing of the GPS signals is to improve the availability and integrity of the navigation solution. It is not anticipated that the accuracy of the P code GPS will be significantly affected by the improvements. At present, the US military utilizes various different RADAR based systems to support landing at military airfields. GPS based approach technology is proliferating in aviation and replacing the aging legacy systems. For landings at military fields, the US military is developing and soon will begin to field JPALS. JPALS uses P(Y) code and local infrastructure to support precision approaches to precision minima. The ability to divert to civilian airfields improves the US military's ability to operate world-wide and gives combatant commanders greater flexibility in air operations. PHASE I: Determine technical feasibility of utilizing only P(Y) Code to meet Category I requirements at any civil airfield world-wide. PHASE II: Develop, demonstrate and validate use of only P(Y) Code to meet Category I requirements at any civil airfield world-wide. PHASE III: Transition and implement the new capability on appropriate platforms. PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Utilization of dual frequency GPS to perform Category I approaches. P(Y) Code would utilize L1 and L2. However, for the civil aircraft, there is a potential to utilize L1 and the coming L2C or L5 frequency to provide Category I approach capability without ground augmentation. This capability would allow/provide for the ability to: The private sector would have the entire DoD fleet of aircraft as potential customers. Dual frequency capability could be used with future C/A code frequencies to provide commercial use in a similar manner. REFERENCES: 2. GNSS Evolutionary Architecture Study, Phase I - Panel Report, February 2008. http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/techops/navservices/gnss/library/documents/media/GEAS_PhaseI_report_FINAL_15Feb08.pdf 3. Phase II of the GNSS Evolutionary Architecture Study, February 2010. https://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/techops/navservices/gnss/library/documents/media/GEASPhaseII_Final.pdf 4. GNSS Evolutionary Architecture Study ARAIM Flight Test Results 5. WAAS/GPS Terms and Definitions. http://www.nstb.tc.faa.gov/Terms.html KEYWORDS: Civil Interoperability; P(Y) Code; Precision Approach; World-wide Divert; Unaugmented;
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