Tag: Wide Area Augmentation System

FAA researching Advanced RAIM for GPS + Galileo approaches

Quarterly reports evaluate ARAIM progress for FAA

Photo: jpgfactory/iStock/Getty Images Plus/Getty Images

An official evaluation of Advanced RAIM (ARAIM), a GPS technique used in aviation receivers for safer landings and take-offs, is being conducted by the William J. Hughes Technical Center (WJHTC) of the U.S. Federal Aviation Administration (FAA).

The WAAS Test Team at the technical center has begun to monitor the Integrity Support Data (ISD) parameters of ARAIM using evaluation tools and methods developed by both the center and Stanford University. Results of this monitoring will be published in a quarterly report on the WAAS Test Team website.

The Need for Advanced RAIM

ARAIM addresses various weaknesses of Receiver Autonomous Integrity Monitoring (RAIM).

To assure the integrity of GPS, aviation receivers implement RAIM, which detects any GPS satellite fault, and can then isolate and remove it from the navigation solution.

However, RAIM provides integrity only for horizontal operations, such as enroute and non-precision approach. Additional integrity is needed to allow advanced capabilities, such as vertically guided approaches. Other integrity systems, including the Wide Area Augmentation System (WAAS), provide the integrity needed to permit these additional operations.

Since RAIM’s debut, GPS and other GNSS have evolved to improve their performance and upgraded to add an additional civilian signal, making possible ARAIM architecture.

ARAIM increases the geometric diversity and integrity availability by using two core GNSS constellations (such as GPS and Galileo). ARAIM takes advantage of the second civilian signal by specifying dual-frequency processing so that the ionospheric error from GNSS signals is directly measured by the user equipment.

The ionosphere — in most cases, the largest source of error in a GNSS signal — can also reduce the integrity of GNSS signals. Data provided for ARAIM use can include improved performance commitments from the GNSS constellation. RAIM uses static values for those performance commitments.

Enabling LPV-200 Approaches

The dual-frequency multi-constellation ARAIM seeks to allow LPV-200 approaches worldwide. LPV-200 (localizer performance with vertical guidance) delivers accurate information on an aircraft’s approach to a runway with the use of GNSS positioning technology. The result is lateral and angular vertical guidance without the need for visual contact with the ground until an aircraft is 200 feet above the runway.

ARAIM is considered an aircraft-based augmentation system: the algorithm to determine GPS integrity is in the aircraft receiver, just like RAIM. ARAIM could use both GPS and Galileo to achieve the worldwide LPV-200 service goal, with the integrity needed available from satellites of both constellations.

Integrity Support Data. An important aspect of ARAIM is the integrity support message, which contains the ISD that describe a GNSS constellation’s accuracy and reliability. Each GNSS constellation service provider generates and updates its ISD data, while the receiver manages and uses each GNSS constellation message.

The specific ISD parameters for ARAIM have not yet been finalized, but candidate data includes the probabilities of satellite and constellation failure (for instance, more than two satellites fail due to a common cause), user range error, user range accuracy data, and other candidate data.

The ISD will be finalized when the International Civil Aviation Organization (ICAO) Standards and Recommended Practices (SARPs) with the ARAIM requirements are completed.

To ensure that the data provided in the ISM remains valid, external monitoring is needed. The external monitoring ensures the satellite and constellation failure probabilities provided in the ISM continue to be valid. External monitoring also characterizes the user range accuracy and user range error in the ISM.

Read more about the project in the FAA’s SatNav News, Fall/Winter issue.

January 30, 2023
Raytheon awarded FAA contract to upgrade WAAS to dual-frequency

WAAS makes airports without ground-based navigation available to pilots. (Photo: Raytheon)

WAAS monitors and evaluates all GPS signals over North America to enable pilots to fly using augmented GPS data for precision landing and enroute navigation

Raytheon Intelligence & Space, a Raytheon Technologies business, has been awarded a competitive indefinite-delivery, indefinite-quantity contract from the Federal Aviation Administration with a ceiling value of $375 million over the next 10 years.

Task orders, valued at $215 million, were executed at contract award to provide technical refresh and dual-frequency operation (DFO) upgrades to the FAA’s Wide-Area Augmentation System (WAAS) to provide safer air travel in support of the National Airspace System.

WAAS monitors and evaluates all GPS signals over North America to enable pilots to fly using augmented GPS data for safety-of-life missions such as precision landing and enroute navigation. The system allows pilots to safely land in places previously inaccessible because of the airport location or weather. It also makes airports without ground-based navigation available to pilots.

Under the WAAS DFO-2 contract, Raytheon will deliver more modern, and therefore sustainable, processing, system security, and network architecture, while also adding dual-frequency service.

“There is no margin for error during take-off, flight or landing,” said Denis Donohue, president, Surveillance & Network Systems at Raytheon Intelligence & Space. “Our modernization effort for WAAS will improve system robustness during ionospheric events and ensure safety-of-life requirements continue to be met.”

WAAS is a satellite-based augmentation system (SBAS) that provides GPS corrections for critical navigation for the aviation community, first responders and other government agencies, ensuring pilots can land safely in austere environments, despite weather challenges. It also provides corrections for SBAS-capable receivers in use across a diverse set of communities, including agriculture, maritime and surveying, among others.

Raytheon Technologies has been the prime development contractor for WAAS since 1996. Since reaching initial operational capability in 2003, Raytheon and the FAA have developed and fielded dozens of enhancements expanding WAAS’ precision approach capability, coverage area, and reliability, including improvements to the system infrastructure in preparation for dual-frequency service.

WAAS dual-frequency service will enable increased system accuracy, integrity and availability when subject to ionospheric perturbations, including solar storms. Work for this effort is based in Fullerton, California.

September 17, 2022
NAVSYS’ role in WAAS

Alison Brown, president & CEO, NAVSYS Corporation

Thirty years ago, NAVSYS was deep into the development of the Wide Area Augmentation System (WAAS). I had the honor of being the chair of the RTCA SC-159 Integrity Working Group, which developed the first concepts for what evolved into three integrity standards for GPS: multi-sensor integration, receiver autonomous integrity monitoring (RAIM) and wide-area differential GPS using a GPS integrity channel (GIC) to broadcast corrections over a geostationary overlay.

NAVSYS, working with Inmarsat Corporation, built the first prototype WAAS SIGGEN equipment, which was deployed at the Coonhilly Coast Earth Station and used to transmit an L-band C/A-code signal over the Inmarsat Atlantic Ocean Region MARECS-B satellite to a software GPS receiver that we had developed and installed at Inmarsat’s Test and Development Laboratory in London.

First Inmarsat Geostationary Overlay Test-Bed, 1991. (Image: NAVSYS)

Image: FAA

This evolved into the FAA’s WAAS program, which used the NAVSYS SIGGEN for the initial deployment, test and evaluation. The algorithms developed by NAVSYS were ultimately licensed to Raytheon for use on the operational WAAS and MSAS systems.

October 5, 2020
Random recollections of GPS/GNSS

2000: An Allstar OEM receiver. (Photo: NovAtel)

GPS had been around for about five years before first launch in February 1978 and Full Operational Capability (FOC) was eventually declared in April 1995. It takes time to develop, field and prove something as complex as the world’s first satellite navigation system. But we’re now well into a third generation of the venerable GPS, with GLONASS, Galileo, BeiDou and IRNSS/NavIC and QZSS around the world and in geographic locales. So, putting aside Transit or anything else, this would make GPS about 47 years old — heading into middle age.

Therefore, it would seem that Glen Gibbons waited until “this GPS thingy” looked like it might actually work — circa 1990 — to launch GPS World, since the magazine is now 30 years old and is also into its third-generation of editor-custodians! Alan Cameron bravely carried the flag after Glen and nurtured the magazine for a good number of years and brought me into the fold as a contributor. We shared ION GNSS conventions and GPS World Leadership dinners and he was able to cajole monthly articles out of me for many years. Now Marty Whitford has his hand firmly on the tiller as publisher, with Tracy Cozzens as senior editor.

So what went down during these decades of technological advancement and for many of the people in the satnav industry? It would be impossible to answer within my word-limit, so I’ll take on an extremely small subset and recount a few things I can still remember.

µGPS. I got into GPS around 1990 in an OEM board-level product spin-off program from a certified GPS airborne receiver at CMC in Montreal — we initally called that L1 receiver µGPS because then it was a small GPS board. Later it became known as the AllStar receiver. We found pretty neat applications for the early ’90s — golf-course systems, vehicle tracking, airport vehicle tracking, the start of vehicle nav systems and such.

At NovAtel in Calgary in the early ’90s, we watched things develop through L1/L2 dual frequency, began RTK market applications in survey, geographic information systems (GIS), agriculture, mining and all multitudes of attempts to get new companies off the ground.

2013: NovAtel’s WAAS G-II reference receiver. (Photo: NovAtel)

WAAS. Eventually the U.S. Wide-Area Augmentation System (WAAS) program came and swallowed us up through three different prime contractors. Once that Federal Aviation Administration program was running well, we were into programs in Europe, Japan, India and China, and that led into Galileo ground reference receivers. The software qualification work we did on Galileo positioned us to take on mil-spec receiver work, and even anti-jam products.

Then CMC bought NovAtel, and we also joined with CMC to develop a certified airborne receiver. In 2003, NovAtel bought the AllStar OEM product line from CMC — funny how things work out! The joint certified receiver program eventually resulted in a new generation of high-accuracy airborne sensors. We again changed hands in 2007 when Hexagon bought us, and then NovAtel began working closely with Hexagon subsidiary Leica on survey applications. Many new and interesting developments are still going on there.

Nowadays, my interests lie with assisted GNSS and with Rx Networks in Vancouver, which I support and advise. Assisted GNSS comes in many forms, has many avenues in the marketplace, and presents its own unique challenges.

As GPS has evolved into GNSS and into so many, many applications, companies have come and gone but the core of people who drive the industry has grown and acquired new and specialized skills, developing ever more capable technology and products. Even after 47 years of the industry and 30 years of GPS World, we aren’t anywhere close to done.

September 9, 2020
Horizon realizes benefits of WAAS; Delta lands GLS approach in Dominican Republic

Horizon realizes benefits of WAAS

More than a decade ago, Horizon Air, a regional affiliate of Alaska Airlines, decided to implement the Wide Area Augmentation System (WAAS) as a part of its overall solution.

According to the Federal Aviation Administration’s (FAA) SatNav News winter 2020 newsletter, the airline has identified a number of benefits from implementing the WAAS, including pre-departure planning, enhanced safety and scheduled reliability.

“Our schedule reliability has become the best in our route structure due to the lowest possible approach minimums at airports Horizon Air serves,” said Perry Solmonson, Horizon Q400 check airman/flight ops duty officer.

Delta lands GLS approach in Dominican Republic

On Oct. 16, 2019, Delta 737 pilots, Captain Jon Hensler and Captain C.E. “Noah” Flood, along with 737NG Technical Manager Mike Mannino, conducted a GBAS Landing System (GLS) approach in Punta Cana, Dominican Republic. According to the FAA SatNav News newsletter, the GLS landing was a first for a North American carrier operating a revenue flight into Latin America.

The Punta Cana airport is the first Latin American airport with GLS capability. GLS approaches at this airport permit significantly lower operational weather minimums, allowing aircraft to safely operate into this airfield when they would otherwise need to divert.

According to the newsletter, the approach was the beginning of a several month Delta trial for GLS approaches at the Punta Cana airport.

Check out the full stories in the FAA SatNav News winter 2020 newsletter here.

April 24, 2020
Raytheon upgrades WAAS with GEO 6 payload

Photo: Nieuwland Photography/Shutterstock

Raytheon has delivered the Wide Area Augmentation System Geosynchronous Earth Orbiting 6 satellite navigation payload to the U.S. Federal Aviation Administration (FAA) to broadcast the WAAS message, which corrects errors in GPS satellite signals, provides expanded coverage, improves accuracy and increases reliability.

The WAAS GEO 6 payload is now operational and fully integrated into the WAAS network, working with two other WAAS satellite payloads already in orbit.

The SES-15 satellite hosting Raytheon’s WAAS GEO 6 payload was launched in 2017 and completed extensive system integration in July 2019.

GEO 6 replaces an older WAAS geostationary satellite that had reached its end-of-service life.

About WAAS. Developed and installed by Raytheon for the FAA, WAAS is a North American satellite-based augmentation system that increases GPS satellite signal accuracy for precision approach at 200 feet altitude to meet strict air navigation performance and safety requirements for all classes of aircraft in all phases of flight.

WAAS contains space and ground equipment that works together to identify GPS satellite corrections.

Operational since 2003, the WAAS network consists of three geostationary satellites and 49 terrestrial-based stations dispersed across the continental U.S., as well as Alaska, Canada, Hawaii, Puerto Rico and Mexico.

“Never has a consistent and precise GPS signal been more critical to ensuring safety of flight,” said Matt Gilligan, vice president of Raytheon’s Intelligence, Information and Services business. “As the airspace increases in complexity, there is absolutely no room for error.”

To learn more about Raytheon’s portfolio of air traffic management solutions, visit here.

November 5, 2019
GEO 5 joins WAAS, giving FAA better coverage across US

The Federal Aviation Administration’s Geosynchronous Earth Orbiting 5 Wide Area Augmentation System (WAAS) navigation payload, developed by Raytheon’s Intelligence, Information and Services business, is now operational and fully integrated into the WAAS network.

The GEO 5 payload joins two others already on orbit in correcting GPS satellite signal ionospheric disturbances, timing issues and minor orbit adjustments, giving users increased coverage, improved accuracy and better reliability, Raytheon said.

“GPS alone can’t meet the FAA’s stringent requirements for accuracy, integrity and availability,” said Matt Gilligan, vice president of Raytheon’s Navigation, Weather and Services mission area. “The WAAS network corrects even the slightest errors, and that provides peace of mind when it comes to safety of flight.”

In operation since 2003, WAAS increases GPS satellite signal accuracy from 10 meters to 1 meter, ensuring GPS signals meet rigorous air navigation performance and safety requirements for all classes of aircraft in all phases of flight, Raytheon added.

WAAS provides precision navigation service to users across the United States from Maine to Alaska, as well as portions of Canada and Mexico.

For aviation users, WAAS offers pilots more direct flight paths, precision airport approaches and access to remote landing sites without depending on local ground-based landing systems.

Raytheon is the system integrator on the GEO 5 system, which includes a WAAS navigation payload on Eutelsat’s GEO satellite, two ComSAT ground sites and SED Systems specialized equipment.

June 21, 2018
Per Enge appointed to Satelles board of directors

Per Enge, Professor and Director, Stanford university Center for Position Navigation and Time

Satelles, a secure time and location solutions company, has appointed Per Enge to its board of directors. Satelles provides a time and location solutions delivered over the Iridium constellation of 66 low-earth-orbiting satellites.

Enge is the Vance and Arlene Coffman Professor of Aeronautics and Astronautics for Stanford University, where he is also the director of the Stanford Center for Position Navigation and Time.

“I am eager to join the Satelles Board of Directors and look forward to supporting the management team,” Enge said. “I am encouraged by the progress Satelles has made and continue to have confidence in the leadership team and future growth of the business.”

Enge’s laboratory has worked with the U.S. Coast Guard to design a medium frequency radio system to broadcast differential GPS corrections to maritime users, and this system has been implemented as a worldwide standard.

His laboratory also worked with the U.S. Federal Aviation Administration to develop WAAS, the Wide-Area Augmentation System that provides GPS integrity data to airborne users. Today, WAAS is carried by more than 100,000 aircraft, and similar systems have been implemented in Europe, India and Japan.

Enge also serves on the board of directors of Amida Technologies, and he serves as a technical advisor to Polaris Wireless.

He has received the Kepler, Thurlow and Burka Awards from the Institute of Navigation for his work. He is a Fellow of the Institute of Electrical and Electronics Engineers. He is a member of the National Academy of Engineering and a fellow of the Institute of Navigation.

Enge received his Ph.D. in electrical engineering from the University of Illinois in 1983. In 2012, the U.S. Air Force inducted Enge into the GPS Hall of Fame.

“It is with great pleasure that we welcome Per to Satelles Board of Directors,” said Michael O’Connor, Satelles CEO. “Per has distinguished himself as a technology innovator and brings to our board of directors deep expertise in global navigation satellite systems. His wealth of experience and expertise in GPS and other technologies adds new depth to our board as we continue to deliver Satellite Time and Location to users around the world. We look forward to working with Per on our mission is to deliver trusted time and location solutions that augment and enhance existing solutions — including GPS.”

August 29, 2017
Raytheon launches WAAS payload to improve GPS accuracy for air travel

Raytheon Company has launched its GEO 6 satellite payload into orbit for its 12-year mission. It is the latest payload to support the Federal Aviation Administration’s (FAA) Wide Area Augmentation System (WAAS), which enhances the reliability and accuracy of GPS signals for directing air travel.

The Raytheon-developed payload is a key element of WAAS, which offers commercial, business and general aviation pilots more direct flight paths, greater runway capability and precision approaches to airports and remote landing sites without dependence on local ground-based landing systems.

“This latest payload launch is the next step in our journey with the FAA to bolster navigation safety and efficiency for commercial and general aviation,” said Bob Delorge, vice president of transportation and support services for Raytheon Intelligence, Information and Services.

In June 2016, Raytheon launched WAAS GEO 5, which was recently accepted by the FAA for integration into the operational WAAS system. Both WAAS GEO 5 and GEO 6 were launched to replace aging satellites and enhance GPS precision for the FAA. WAAS increases GPS accuracy from 10 meters to approximately two meters and supports nearly all of the national airspace.

The WAAS GEO 6 payload is hosted on a geostationary satellite, SES-15, owned and operated by SES. The satellite was successfully launched May 17 from Arianespace’s Guiana Space Center in French Guiana aboard a Soyuz launch vehicle.

May 22, 2017