Satellite Navigation - NAS Implementation

National Airspace System Implementation

The objective of National Airspace System Implementation is to develop the operational infrastructure to support the certification process for satellite navigation and provide the technical basis for the development of GPS operational procedures for all phases of flight. NAS Implementation communicates and cooperates with numerous governmental and non-governmental agencies to pave the way for a smooth transition to satellite navigation.

The FAA's GPS implementation activities are dedicated to the adaptation of the NAS infrastructure to accept Satellite Navigation (SatNav) technology. In short, implementation puts an operational face on satellite navigation for NAS users and service providers. The implementation team is instrumental in ensuring that each aspect of the NAS infrastructure is prepared for satellite navigation through the management and coordination of a variety of overlapping NAS implementation projects.

Alaska Obstruction and Airspace Analysis

Obstruction Evaluation & Airport Airspace Analysis Program

• Anchorage Office Point of Contact
• Determinations, Search or View
• Alaska - Determinations of No Hazard to Navigation
• Tower Light Point of Contact

FCC Antenna Structure Registration Search

• Alaska Constructed Antenna Towers 199 Feet Above the Ground and Taller
• Alaska's Tallest Towers

Juneau & Ketchikan

Juneau & Ketchikan Airport Areas

Useful Information When Flying in Southeast Alaska

• Juneau FSS
• Juneau Avalanche Control
• Juneau Enroute Common Traffic Advisory Frequency (CTAF) Areas(PDF, 126 KB)
• Juneau Harbor Seaplane Base Float Plane Procedures(PDF, 78 KB)
• Juneau Airport Wind System(JAWS)
• Juneau Inset, Visual Check Points, and Flight Advisories
• Ketchikan Flight Service Station(FSS)
• Ketchikan Special Air Traffic Rules, Check Points, and Traffic Patterns
• Other Notices

Juneau Flight Service Station

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Overview of the Alaskan Panhandle Weather Patterns

Generally, weather patterns ranging from Prince William Sound to Ketchikan are dominated primarily by low pressure systems advecting warm, moist, Pacific Ocean air over steep mountainous shorelines throughout the area causing precipitation from onshore and upslope flow, temperature inversions, and other surface based frictional effects. The region is classified as having a maritime climate and coastal areas located along the central and Southeastern portion of the region are consistent with rain forest climactical characteristics. Seasonal changes are good indicators of the type of weather that can be expected in the region.

During the winter months as the polar air mass moves southward and strengthens with the jet stream, clear skies associated with high pressure centers located in Northwestern Canada may be seen frequently. The development of arctic air masses situated within the polar airmass establish frontal boundaries along steep temperature gradients which divide these air masses. Frontal activity associated with the pressure systems also plays a major role in weather development along the interior coastal areas of the Southeast. Cold stable air during the winter will generally cause widespread uniform precipitation and low level stratiform clouds. Scattered areas of IFR conditions are common due to decreased visibility associated with frequent bouts of heavy snowfall, mountain obscuration, and radiation fog and rain induced fog. Icing can be a threat year round in the region and is amplified during the winter months when a low-pressure system situated over the ocean brings moisture over the dominant colder air masses inland. Normally, this is apparent by the presence of occluded fronts depicted on the surface analysis charts. It is not uncommon to have multiple freezing levels even during the winter months in the panhandle area.

During the summer months diurnal effects of radiational heating and cooling will cause convective turbulence and windshear associated with instability. Sea breezes and upslope wind flow are often responsible for adverse weather conditions along mountainous coastal areas.

Pressure gradient force is a major factor in the development of localized weather systems. The steep slopes of the mountainous terrain along with the existence of numerous and very large glaciers, located throughout the region, have a tremendous impact when combined with strong winds. The venturi effect of winds blowing through narrow passes and valleys causes lifting, when the air is moist. IFR conditions may develop, windshear and mechanical turbulence can be extreme depending on the velocity of the wind. Areas such as Valdez, Yakutat, and Juneau have specific terrain features that can cause adverse conditions whenever strong winds from specific directions are present. Wind blowing over glaciers adds a temperature factor. Many of the glaciers situated throughout the region create their own weather patterns in the immediate vicinity.

Specific to aviation, weather reports and pilot reports are of extreme importance throughout the area due to the characteristic of localized weather development. The specific area's containing adverse conditions are often not large enough to warrant regional issuance of weather advisories.

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Juneau Flight Service Station

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Dedicated to the Memory of David Scheytt

On July 6, 1984, local helicopter pilot David Scheytt and his co-pilot, Doug Brown, were notified of an aircraft crash in a pond near the Juneau Airport.  Reacting immediately, the two raced for a helicopter and proceeded to the scene of the accident. Upon their arrival, they found the passenger, Alaska Sate Trooper Nils Monsen, injured and in shock near the submerged wreckage of the aircraft, while the pilot, Trooper Cpl. Warren Grant, was still strapped in the cockpit. Mr. Brown leaped into the water, dove down to free Cpl. Grant, and brought him to the surface. In the meantime, Mr. Scheytt ferried Trooper Monsen to shore into the hands of rescuers, and then returned to the crash site.  The heroic actions of this crew undoubtedly saved at least one life on this date and forever earned the gratitude and respect of the Alaska State Troopers, and the families and friends of the victims.

Less than one year later, Mr. Scheytt tragically lost his life when the helicopter he was flying crashed near the Greens Creek Mine on Admiralty Island.

In honor of his heroic achievement and his selfless actions, the Alaska Peace Officers Association and the Federal Aviation Administration are proud to dedicate this building to the memory of …

Mr. David Scheytt

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Juneau Flight Service Station

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Alaska Maps and Graphics

• Alaska FSS RCOs(GIF, 40 KB)
• Alaska Locations(GIF, 46 KB)
• Alaska Local Time to UTC Time Conversion(GIF, 138 KB)
• Alcan(GIF, 142 KB)
• Alcan Routes(GIF, 54 KB)
• Ft. Wainwright Controlled Firing Area(GIF, 409 KB)
• Four Letter Identifiers(GIF, 240 KB)
• Rivers and Passes(GIF, 63 KB)

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Alaskan Flight Service Stations

FSS's

• Fairbanks FSS
• Juneau FSS
• Kenai FSS
• RCO Map

Satellite Navigation - GPS - Control Segment

GPS - Control Segment

The Control Segment of GPS consists of:

Master Control Station: The master control station, located at Schriever Air Force Base in Colorado Springs, Colorado, is responsible for overall management of the remote monitoring and transmission sites. GPS ephemeris being a tabulation of computed positions, velocities and derived right ascension and declination of GPS satellites at specific times, replace "position" with "ephemeris" because the Master Control Station computes not only position but also velocity, right ascension and declination parameters for eventual upload to GPS satellites.

Monitor Stations: Six monitor stations are located at Schriever Air Force Base in Colorado, Cape Canaveral, Florida, Hawaii, Ascension Island in the Atlantic Ocean, Diego Garcia Atoll in the Indian Ocean, and Kwajalein Island in the South Pacific Ocean.Six additional monitoring stations were added in 2005 in Argentina, Bahrain, United Kingdom, Ecuador, Washington DC, and Australia. Each of the monitor stations checks the exact altitude, position, speed, and overall health of the orbiting satellites. The control segment uses measurements collected by the monitor stations to predict the behavior of each satellite's orbit and clock. The prediction data is up-linked, or transmitted, to the satellites for transmission back to the users. The control segment also ensures that the GPS satellite orbits and clocks remain within acceptable limits. A station can track up to 11 satellites at a time. This "check-up" is performed twice a day, by each station, as the satellites complete their journeys around the earth. Noted variations, such as those caused by the gravity of the moon, sun and the pressure of solar radiation, are passed along to the master control station.

Ground Antennas: Four ground antennas monitor and track the satellites from horizon to horizon. They also transmit correction information to individual satellites.

Satellite Navigation - GPS - Space Segment

GPS - Space Segment

The space segment includes the satellites and the Delta rockets that launch the satellites from Cape Canaveral, in Florida. GPS satellites fly in circular orbits at an altitude of 10,900 nautical miles (20,200 km) and with a period of 12 hours. The orbits are tilted to the earth's equator by 55 degrees to ensure coverage of polar regions. Powered by solar cells, the satellites continuously orient themselves to point their solar panels toward the sun and their antenna toward the earth. Each of the 32 satellites, positioned in 6 orbital planes, circles the earth twice a day.

The satellites are composed of:

Solar Panels. Each satellite is equipped with solar array panels. These panels capture energy from the sun, which provides power for the satellite throughout its life.

External components such as antennas. The exterior of the GPS satellite has a variety of antennas. The signals generated by the radio transmitter are sent to GPS receivers via the L-band antennas. Another component is the radio transmitter, which generates the signal. Each of the 32 satellites transmits it's own unique code in the signal.

Internal components such as atomic clocks and radio transmitters. Each satellite contains four atomic clocks. These clocks are accurate to at least a billionth of a second or a nanosecond. An atomic clock inaccuracy of 1/100th of a second would translate into a measurement (or ranging) error of 1,860 miles to the GPS receiver.

Satellite Navigation - GPS - User Segment

GPS - User Segment

• Aviation
• Non-Aviation

The user segment includes the equipment of the military personnel and civilians who receive GPS signals. Military GPS user equipment has been integrated into fighters, bombers, tankers, helicopters, ships, submarines, tanks, jeeps, and soldiers' equipment. In addition to basic navigation activities, military applications of GPS include target designation, close air support, "smart" weapons, and rendezvous.

With the surge in popularity of GPS receivers over the past several years, the civilian community has its own large and diverse user segment. Surveyors use GPS to save time over standard survey methods. GPS is used by aircraft and ships for enroute navigation and for airport or harbor approaches. GPS tracking systems are used to route and monitor delivery vans and emergency vehicles. In a method called precision farming, GPS is used to accurately guide farm machinery engaged in plowing, planting, fertilizing, and harvesting. GPS is available as an in-car navigation aid and is used by hikers and hunters. Most smartphones feature GPS map or navigation applications. Because the GPS user does not need to communicate with the satellite, GPS can serve an unlimited number of users.

The aviation community is using GPS extensively. Aviation navigators, equipped with GPS receivers, use satellites as precise reference points to trilaterate the aircraft's position anywhere on or near the earth. GPS is already providing benefits to aviation users, but relative to its potential, these benefits are just the beginning. The foreseen contributions of GPS to aviation promise to be revolutionary. With air travel nearly doubled in the 21st Century, GPS can provide a cornerstone of the future air traffic management (ATM) system that will maintain high levels of safety, while reducing delays and increasing airway capacity. To promote this future ATM system, the FAA's objective is to establish and maintain a satellite-based navigation capability for all phases of flight.