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Integrating Evolving Military GPS Receiver Technology and Enhanced Loran with New and Legacy Shipboard Systems. William R. Woodward, P. E., UrsaNav Richard Webb, UrsaNav. Presentation Objective.
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Integrating Evolving Military GPS Receiver Technology and Enhanced Loran with New and Legacy Shipboard Systems William R. Woodward, P. E., UrsaNav Richard Webb, UrsaNav
Presentation Objective • Introduce the audience to the efforts within UrsaNav to develop a scalable Position, Navigation, and Timing (PNT) gateway that can: • Interface with existing and future GPS receivers. • Interface with existing and future eLORAN receivers. • Interface with existing and future navigation and weapon systems.
Introduction • GPS receiver and antenna technology is continually advancing. • GPS receivers are getting smaller, requiring less power, and tracking more satellites.
Introduction • GPS receivers are available with digital interfaces to support multi-beam anti-jam antennas. • Today’s GPS receivers and antennas provide superior jamming immunity over legacy GPS receivers and antennas.
Introduction • Today manufacturers of military GPS receivers typically offer multiple form factors with a variety of interfaces. • They may all feature common interfaces such as RS-422 or RS-232. • However, interface protocols and data message formats vary from GPS receiver to GPS receiver.
Introduction • A typical military GPS receiver will support one or more Interface Control Document (ICD). • The ICD identifies and defines the interface protocol and associated data message formats for the GPS receiver.
Introduction • While military GPS receiver and antenna technology continue to advance, many legacy shipboard Position, Navigation, and Timing (PNT) interfaces have remained unchanged for decades and may remain unchanged for decades to come.
Introduction • Most shipboard navigation and weapon system interfaces are unique to the shipboard environment and are not found on any current military GPS receiver.
Background • The AN/WRN-6 Satellite Signals Navigation Set serves as the primary source for PNT information on more than 230 U.S. Navy, USCG, and Military Sealift Command (MSC) platforms. • The AN/WRN-7, an unclassified version of the WRN-6, is the primary source for PNT information on approximately 250 foreign military ally ships.
Background • The AN/WRN-6 and AN/WRN-7 supply data to the navigation or weapons system via the dual MIL-STD-1397 Naval Tactical Data System (NTDS) Type A or Type B interfaces. • These interfaces are not available in any other military GPS receiver.
Background • The radio receiver features additional interfaces: • Synchro interface for roll, pitch, heading, and speed input • Precise Time and Time Interval (PTTI) interface • HAVEQUICK interface • ICD-GPS-150 instrumentation port
Background • The Navigation Sensor System Interface (NAVSSI) suite is the primary source for PNT information on major combatants, including 122 U.S. Navy surface platforms and several allied Aegis platforms.
Background • NAVSSI will not accept new GPS receiver technology without the development of a VME circuit card to replace the GPS VME Receiver Card (GVRC) currently used.
Background • The Maritime Embedded Global Positioning System Adapter (MEGA) is in development to replace the GVRC. • It only supports the SAASM compliant GPS Receiver Application Module (GRAM) receiver in a modified Standard Electronic Module type “E” (SEM-E) form factor.
Scenario • The AN/WRN-6, AN/WRN-7, and the GVRC are obsolete. • The AN/WRN-6 and GVRC do not meet some of the newer requirements for a GPS provider. • They are not SAASM compliant.
Scenario • MEGA, will offer NAVSSI SAASM compliance as it is currently defined. • Future upgrades to MEGA will depend on how long the SEM-E form factor airborne GPS receiver is supported with the current ICD that MEGA accepts.
Scenario • The U.S. Navy should have the capability to rapidly upgrade to the latest GPS technology at a minimum cost with no impact to existing shipboard systems.
Scenario • The U.S. Navy and foreign military ally ships need a scalable PNT gateway that can interface with current and future GPS receivers, and existing and future navigation and weapon systems.
Scenario • To minimize installation time and costs, this PNT gateway must accept existing shipboard cabling and mounts. • In the case of NAVSSI, the PNT gateway could mount in a NAVSSI rack and interface with NAVSSI via a VME adapter circuit card.
Solution • UrsaNav is developing a scalable PNT gateway that can interface with current and future GPS receivers, and with existing and future navigation and weapon systems.
Solution • The UN-106™ is based on the current production UN-100™. • It will work across all U.S. Navy, and other service, platforms currently using the WRN-6 and foreign military allies currently using the WRN-7. • It can be configured to be the PNT source for NAVSSI.
Solution • The UN-106™ will accept multiple form factor GPS receivers such as the: • GB-GRAM • SEM-E form factor airborne GPS receiver • Hand-held receiver such as the DAGR • Commercial GPS receiver
Solution • The UN-106™ will interface the selected GPS receiver to existing and future navigation and weapon systems without requiring software or hardware changes to any of the existing shipboard systems.
Solution • As GPS receiver technology evolves, and their ICDs change, only the UN-106™ will need to be updated. • Legacy shipboard systems will interface with the UN-106™ as if it was a WRN-6 or WRN-7. • NAVSSI will interface with the UN-106™ just as it interfaces with the GVRC and MEGA.
Solution • The IP-1747/WSN Enhanced Control Display Unit (ECDU) installed on SSN 688 and SSN 21 Class submarines will interface with the UN-106™, just as NAVSSI does.
Solution • The UN-106™ mounts in AN/WRN-6 original location and accepts existing shipboard connectors and cables. • The UN-106™ is lighter and uses less power then the AN/WRN-6.
Solution • The UN-106™ can be made smaller, but pigtails will be required to connect to existing shipboard cables. • Pigtails increase installation time, costs, and are another point of failure that decreases the overall reliability of the system.
Solution • The receptacles on the back of the UN-106™ are in the same location as they are on the WRN-6.
Solution • The UN-106™ is scalable. • I/O modules can be installed or removed as required. • Costs are held to a minimum because: • Only the modules required to support the interfaces for that ship need be installed. • Additional interfaces can be installed on site in a short period of time.
Solution • The UN-106™ will accept inputs from multiple GPS receivers in different form factors. • Receivers can be internal or external to the UN-106™.
Solution • Multiple GPS receivers offer several advantages over a single GPS receiver. • They provide graceful performance degradation and the ability to detect and isolate a failed or poorly performing receiver. • A failed internal receiver could be temporarily replaced with a hand-held receiver, such as the DAGR.
Solution • For FMS platforms, the export of current SAASM GPS receivers or future M-Code GPS receivers to some foreign military allies may be restricted. • These countries may be allowed to use the Precision Lightweight GPS Receiver (PLGR).
Solution • The UN-106™ will accept external GPS receivers with interfaces such as ICD-GPS-150, ICD-GPS-153, and NMEA 0183/2000. • If a foreign military ally is not allowed to use a military GPS receiver, a commercial GPS receiver can be substituted.
Solution • The UN-106™ can interface with other PNT technology besides GPS. • Enhanced Loran, or eLoran, is an internationally recognized PNT and Data (PNT&D) service independent of GPS.
Solution • The United States Department of Homeland Security has designated eLoran as a national system that will: • Complement the GPS in the event of an outage or disruption in service • Mitigate any safety, security, or economic effect of a GPS outage or disruption.
Solution • eLoran is a modernization of the land-based Loran-C system and by its very nature operates independently of GNSS. • eLoran provides similar continuous PNT services as GNSS but at different levels. • eLoran can provide a cross-modal radionavigation system backup or complement to GPS.
Solution • Recent tests have indicated that eLoran meets or exceeds the accuracy, availability, integrity, continuity, and coverage requirements necessary to achieve 8-20 meter maritime Harbor Entrance Approach (HEA) and aviation RNP 0.3 nm Non-Precision Approach (NPA) levels of performance.
Solution • The UN-106™ will interface with eLoran receivers such as • Symmetricom’s Enhanced Loran Research Receiver • Reelektronika’s Integrated LORADD eLoran/GPS receiver
Solution • eLoran can provide PNT information when GPS, or other satellite PNT services, are denied, interrupted, or disrupted.
Solution • The UN-106™ accepts multiple PNT inputs, real time position information from the navigation system, and speed information from the ship’s log. • The UN-106™ can evaluate the accuracy of its inputs, detect errors, and alert the operator with a descriptive message.
Solution • The alert range can be set to alert for position differences between a PNT source and the navigation system and position differences between PNT sources.
Solution • This approach to interfacing state-of-the-art SAASM GPS performance with shipboard navigation and combat/weapons systems has been proven onboard several vessels, including the Hellenic Navy’s Kalypso and Evniki.
Functional Diagram as Installed Onboard HN Kalypso and HN Evniki Military GPS antenna Commercial DGPS antenna UN-100™ Commercial DGPS receiver DAGR GPS SAASM receiver Navigation System/Combat System: AN/SYQ-13 Remote Remote Solution
