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  • Risks to the System | Time and Navigation
    satellite navigation systems Satellites provide essential navigation services but threats exist to their operation Radio interference from both natural and human sources presents serious problems for the system s myriad users Engineers and scientists continue to develop solutions to ensure the continued operation of global navigation services Solar Interference Solar activity can interfere with satellite signals Solar storms occasionally interrupt clear reception of signals from space Those who design satellite systems must plan for these disruptions and be aware of how solar activity varies with the 11 year sunspot cycle System Maintenance The successful operation of a satellite navigation system requires around the clock monitoring of the satellites health and the periodic replacement of older satellites The process is labor intensive and expensive and requires multiple backups to ensure continuous operation Man made Radio Interference GPS and other satellite positioning systems were designed to use quiet parts of the spectrum However these channels face the danger of being overwhelmed by communications signals from other nearby frequencies Engineers must test the possibility of interference from multiple systems Intentional Jamming Although their use is illegal in the United States portable GPS jammers are traded clandestinely and used by those who wish not to be tracked or otherwise located by GPS These devices cause nearby navigation systems to malfunction potentially threatening public safety System Under Attack The increasing reliance on navigation satellites for military and commercial activities makes them a tempting target for an enemy While it is difficult to disable the satellites themselves these and other GPS components must be protected from interference or attack Solar Interference Solar activity can interfere with satellite signals Credit NASA SDO and the AIA EVE and HMI science teams Solar Flare Intense solar activity causes material to erupt from the Sun Credit NASA SDO and the

    Original URL path: http://timeandnavigation.si.edu/satellite-navigation/gps/risks-to-system (2016-02-13)
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  • International Systems | Time and Navigation
    Developing Inertial Navigation The First Satellite Navigation System Transit Satellites Navigating a Submarine Improving Satellite Navigation Clocks in Space Evolving Solutions Global Positioning System GPS GPS Begins The Satellite Constellation Synchronized Accurate Time Risks to the System International Systems Who Uses Satellite Navigation Military Applications Civilian Applications The Commercial Market Improving Accuracy Looking Ahead Explore More Cesium Frequency Standard The Blue Force Tracker System NRL s NTS 2 Team Deputy Chief of the Worchester Fire Department John F Sullivan TIMATION 1 Satellite International Systems As in the past nations with global ambitions continue to seek global navigation capabilities The GPS system operated by the United States is not the only satellite navigation system In the 1990s and 2000s many nations began developing or improving their own systems Who s in Charge of Satellite Navigation Systems Different nations develop and deploy independent navigation capabilities Multiple constellations of satellites can improve positioning navigation and timing for everyone Planning is required so systems do not interfere with each other International Systems GPS Operated by the U S Department of Defense and coordinated with the U S Department of Transportation and other civilian government agencies GLONASS Initially developed by the Soviet Union during the Cold War and now operated as a global system by Russia s Federal Space Agency Galileo Under development as a civilian operated global system by a consortium of European nations Operations are coordinated by an agency under the auspices of the European Commission Beidou The Beidou Navigation Satellite System BDS was planned and developed by the government of China Global coverage with about 35 satellites was planned for 2020 IRNSS The Indian Space Research Organisation ISRO began developing the Indian Regional Navigational Satellite System IRNSS in 2006 to provide positioning services around India QZSS The Japanese government planned to develop

    Original URL path: http://timeandnavigation.si.edu/satellite-navigation/gps/foreign-systems (2016-02-13)
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  • Military Applications | Time and Navigation
    cargo bundles delivered by the Joint Precision Air Drop System JPADS to a drop zone in Afghanistan Credit U S Air Force Military Applications Time and positioning go beyond navigation GPS has become an indispensible military asset and transformed space into a platform for war Public awareness of GPS grew during the 1990 91 Persian Gulf War which showcased its effectiveness to synchronize operations provide navigation information pinpoint targets and locate personnel GPS now is the core navigation system for U S military aircraft vessels vehicles and personnel It has changed the nature of weapons targeting command and control guidance of unmanned systems and supply delivery on the battlefield Precision Lightweight GPS Receiver PLGR The handheld Precision Lightweight GPS Receiver PLGR popularly known as the Plugger replaced the Manpack in 1993 These units were similar to civilian receivers of the time but used higher precision GPS signals Learn more Defense Advanced GPS Receiver DAGR Beginning in 2004 Rockwell Collins made a smaller handheld military GPS receiver The Defense Advanced GPS Receiver DAGR pronounced dagger integrates a map graphic with two channels of GPS signals coded specifically for the military and map graphics Predecessor receivers showed only words and numbers Learn more Honeywell RQ 16 T Hawk Micro Air Vehicle MAV This autonomous air vehicle uses GPS and inertial navigation for observation missions in hazardous situations without exposing its operator to risk RQ 16s provided the first detailed interior imagery of damaged nuclear reactors in Japan during 2011 and have flown with police SWAT teams and military bomb disposal units Learn more Joint Precision Air Drop System JPADS Parachute and Guidance Unit Aircraft dropping supplies by parachute have to fly at dangerously low altitudes Material can miss the intended target and fall into enemy hands This GPS guidance unit and parafoil

    Original URL path: http://timeandnavigation.si.edu/satellite-navigation/who-uses-satellite-navigation/military-applications (2016-02-13)
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  • Civilian Applications | Time and Navigation
    System GPS GPS Begins The Satellite Constellation Synchronized Accurate Time Risks to the System International Systems Who Uses Satellite Navigation Military Applications Civilian Applications The Commercial Market Improving Accuracy Looking Ahead Explore More Precision Lightweight GPS Receiver PLGR Ship s Inertial Navigation System SINS UAT Universal Access Transceiver Lockheed SR 71 Blackbird in Flight Experimental Chip Size Atomic Clock Civilian Applications Civilians begin to use satellite navigation Manufacturers of GPS receivers for military users Texas Instruments Rockwell Collins Magnavox and Interstate Electronics were the first to offer them to civilians especially scientists and surveyors Receivers gradually grew smaller more portable and more user friendly Around the year 2000 demand exploded as new devices and more accurate signals gradually became available Scientists were eager to use satellite navigation signals for time and position GPS receivers gave them access to accurate measurements for research and surveying GPS for All The Magellan Corporation released the first widely available handheld civilian GPS receiver in 1988 In the coming years the U S market for GPS devices grew to billions of dollars and multiple manufacturers produced diverse units to meet the demand As technology advanced GPS receivers became smaller and easier to use and included more features Most early units provided simple map data while later devices incorporated information and communication links Emergency Vehicle Location System This equipment made up a prototype emergency location service based on GPS positioning Credit National Museum of American History Smithsonian Institution PNT Positioning Navigation and Timing All three positioning navigation and timing are used together with map data and other information weather or traffic data for instance in modern navigation systems Credit National Air and Space Museum Smithsonian Institution Video of Global Transportation Links Global Transportation Links Length 20 Seconds Credit National Air and Space Museum Smithsonian Institution previous

    Original URL path: http://timeandnavigation.si.edu/satellite-navigation/who-uses-satellite-navigation/civilian-applications (2016-02-13)
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  • The Commercial Market | Time and Navigation
    Navigation Navigation for Everyone Timeline of Innovation Artifacts Learning Resources Multimedia Gallery Research Journal Visit the Exhibition Satellite Navigation Challenges of Satellite Navigation Navigation Gone Wrong Soviets Shoot Down an Airliner Reliable Global Navigation Inertial Navigation Charles Stark Draper Developing Inertial Navigation The First Satellite Navigation System Transit Satellites Navigating a Submarine Improving Satellite Navigation Clocks in Space Evolving Solutions Global Positioning System GPS GPS Begins The Satellite Constellation Synchronized Accurate Time Risks to the System International Systems Who Uses Satellite Navigation Military Applications Civilian Applications The Commercial Market Improving Accuracy Looking Ahead Explore More Magellan NAV 1000 GPS Receiver 1988 The Second Transit Satellite Under Inspection Transit Receiver Mounted in a Vehicle in the Egyptian Desert Juno Spacecraft Approaching Venus Planning the Creation of the Global Positioning System The Commercial Market During the late 1980s several companies began developing GPS receivers for a broader civilian and commercial market The receivers were designed for recreational purposes as well as for emergency responders Although not open to the most accurate signals these early GPS devices provided map coordinates from anywhere on the globe GPS Use during Mountain Climbing Jim Whittaker uses a Magellan GPS receiver on Mt Rainier Credit Dianne Roberts TI 4100 NAVSTAR Navigator GPS Receiver This is one of the first commercial GPS receivers Credit National Air and Space Museum Smithsonian Institution previous pause resume next Innovations Magellan GPS Test Components Breadboard This breadboard was used to test circuitry and components at Magellan while developing early GPS units Learn More See additional innovations How it Works How it Works How Does GPS Work From maintaining infrastructure transporting goods delivering services or just meeting friends people often use technology just as sophisticated as that used by pilots and soldiers How does it work Learn More Navigating at Sea Challenges of

    Original URL path: http://timeandnavigation.si.edu/satellite-navigation/who-uses-satellite-navigation/civilian-applications/commercial-market (2016-02-13)
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  • Improving Accuracy | Time and Navigation
    Who Uses Satellite Navigation Military Applications Civilian Applications The Commercial Market Improving Accuracy Looking Ahead Did You Know During the Persian Gulf War in 1991 the military lacked enough GPS receivers To satisfy demand the Defense Department acquired civilian units and temporarily lifted Selective Availability Explore More GPS Block III Satellite Magellan NAV 1000 GPS Receiver 1988 Cesium Brassboard Frequency Standard Roy Bardole in His Tractor Motorola LGT 1000 1994 Improving Accuracy Civilians begin to gain access to better accuracy As originally designed GPS included Selective Availability an aspect of the system that inserted timing errors into the transmissions to limit the accuracy of nonmilitary receivers During the Persian Gulf War in 1991 the military lacked enough GPS receivers To satisfy demand the Defense Department acquired civilian units and temporarily lifted Selective Availability Selective Availability was permanently eliminated in 2000 making it possible for civilian receivers to provide four to five times greater accuracy and helping boost the GPS market Code in GPS Signals Signals sent by GPS satellites are complicated What we learn from these signals depends on the type of equipment we use to receive them A military pilot needs more information than someone using GPS in a car More Accuracy for Professional Surveys Specialized GPS equipment was developed for high precision surveys during the 1990s Differential GPS uses two sources of GPS data to provide high accuracy Surveyors used this type of system to accurately map infrastructure and survey large sites GPS Use during Mountain Climbing Jim Whittaker uses a Magellan GPS receiver on Mt Rainier Credit Dianne Roberts GPS Accuracy With and Without Selective Availability The image shows accuracy to within a radius of about 20 feet 6 meters Credit National Air and Space Museum Smithsonian Institution GPS Accuracy With and Without Selective Availability The image

    Original URL path: http://timeandnavigation.si.edu/satellite-navigation/who-uses-satellite-navigation/civilian-applications/improving-accuracy (2016-02-13)
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  • Looking Ahead | Time and Navigation
    life Opportunities for innovation abound So do challenges and questions How can navigation tools remain available Can we become too dependent on the technology Who will decide what gets developed What comes next for time and navigation Future Clocks Innovations in timing technology could improve navigation even further To make and run the most accurate clocks today you need a laboratory There atomic clocks can be as big and power hungry as necessary But could someone build a tiny wristwatch size atomic clock that stays as accurate as its larger clock cousins yet consumes little power and costs less to build Researchers are working on just such clocks to back up the atomic clocks in GPS satellites One day they could be part of every GPS receiver or provide timing for communications of all sorts NextGen A revolution in air traffic control promises safer and more efficient air travel In 2003 U S aviation agencies joined those of other nations in a program to modernize how global air traffic is managed Based on satellite positioning the Next Generation Air Traffic System or NextGen is replacing the existing network of ground based navigation beacons and radar Robots on the Road Satellite navigation systems may one day shape how and what you drive Researchers around the world are beginning to craft a future where drivers with electronically enhanced cars buses and trucks will navigate automated highways Transportation planners hope to create a highly efficient road system and to foster the technologies to make it happen Will your next car drive itself Volkswagen Touareg Stanley Stanley is an autonomous robotic vehicle that won the 2005 Grand Challenge Credit National Air and Space Museum Smithsonian Institution United Airlines Boeing 787 in Flight Satellite navigation is creating significant changes in the infrastructure of air navigation

    Original URL path: http://timeandnavigation.si.edu/satellite-navigation/who-uses-satellite-navigation/civilian-applications/looking-ahead (2016-02-13)
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  • Magellan 2000 XL, 1996 | Time and Navigation
    Smithsonian Institution Origin National Air and Space Museum Smithsonian Institution Creator Dane A Penland NASM2012 02116 Related Resources Topics Navigation Tools Satellite Navigation Innovations GPS Navigation Methods Satellite Navigation Keyword Search Search by MEDIA Any Animation Artifact Document Film Illustration Map Newsreel Photograph Search by TOPIC Any Maps and Charts Navigating at Sea Navigating in Space Navigating in the Air Navigation for Everyone Navigation Tools Satellite Navigation Significant Voyages Timekeeping Innovations Any 621B A 12 Sextant Aerial Sextant Air Position Indicator Aircraft Astrocompass Astrodome Astrograph Astroinertial Navigation System Atomic Clock Bubble Sextant Celestial Computer Celestial Navigation Trainer Celestial Table Charts Chronometer Compass Dead Reckoning Computer Drift Indicator Drift Meter Drift Sight E 6B Float Light GEE Giovilabio GOES GPS Lindbergh Hour Angle Watch Line of Position Longitude LORAN Maps Mechanical Mike Mechanical solutions Navigational Radar Octant Pendulum Clock Periscopic Sextant Plotting Pre Comp Navigation Quartz Clock Quartz Oscillator Quartz Resonator Radio Compass Radio Range Radio Time Signals Radius of Action book Satellite Sea Chronometer Sea Clock SECOR Sextant SINS Star Altitude Curves Tables Timation Transit VOR Windscreen ZB 1 Radio Homing Adapter Navigation Methods Any Celestial Navigation Dead Reckoning Inertial Navigation Radio Navigation Satellite Navigation Navigators Inventors Any Bert Acosta John Arnold Lloyd Bertaud Ferdinand Berthoud Charles Blair William Cranch Bond Nathaniel Bowditch Emory B Bronte L C Bygrave Richard Byrd Jorge de Castilho François Coli Douglas Corrigan Dieudonné Costes Eleanor Creesy Harry H Crosby Philip Dalton William Davis Jr Charles Stark Draper Amelia Earhart Thomas Earnshaw Lincoln Ellsworth Galileo Galilei Harold Gatty Art Goebel George Haldeman Leslie Hamilton John Harrison Albert F Hegenberger Christiaan Huygens Amy Johnson Lisette Kapri Vilas Knope Curtis LeMay Charles Levine Anne Morrow Lindbergh Charles Lindbergh Ed Link Alfred Lee Loomis James A Lovell Jr James V Medcalf Henry Dick Merrill Thomas Mudge Jet Propulsion

    Original URL path: http://timeandnavigation.si.edu/multimedia-asset/magellan-2000-xl-1996 (2016-02-13)
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