Garmin Offers WAAS LPV Receivers

by Tom Driehorst, GPS TAC/FAA ATO-W

LPV-capable Wide Area Augmentation System (WAAS) avionics are hitting the marketplace. Garmin

International’s GNS 480 now meets

the strictest level of certification for

WAAS navigation. Previously, Instrument Landing System (ILS) availability was needed for a precision approach in low-visibility conditions.

The GNS 480 will utilize satellitebased navaids for precise lateral and vertical approach guidance — similar to ILS operations — without the need for ground-based navaids of any kind, since avionics certified to

Gamma-3 requirements meet the FAA’s standards for LPV guidance.

At the heart of the GNS 480 is a 15-channel WAAS receiver that updates the aircraft’s

position at a rate of five times per second. The GNS 480 provides oceanic-approved IFR

GPS/NAV/COM functionality and ILS/VOR capabilities—but does so on a 3.8-inch

(diagonal), 256-color moving-map display.

According to the Garmin representatives at the AOPA Expo, LPV upgrade modifications

to the existing Garmin GNS 530/430 series avionics will be available in the summer of

2005 for approximately $1,500. Current 530/430 users will need to send their unit to a

factory facility to receive the modification.

WAAS - A Pilot’s View

by Larry O. Oliver, GPS TAC/FAA ATO-W

I’ve spent many years using just Very High Frequency (VHF) Omnidirectional Range Receiver (VOR) for navigation. Eventually, I upgraded

to Distance Measuring Equipment (DME), and found that my workload

decreased and my navigational confidence went up immensely. Several years ago I started

using the Global Positioning System (GPS), and I was amazed at the capabilities it presented. Suddenly, the old areas of navigational uncertainty were gone, and I could alter

my destination en route with confidence in my time and distance to the new airfield.

Now, I am faced with the Wide Area Augmentation System (WAAS). Frankly, I’m pretty

happy—no, make that thrilled—with GPS, so what will WAAS get me?

The SATNAV News SATNAV News is SATNAV News produced by the

Navigation Services (ATO-W) branch of

the Federal Aviation Administration

(FAA). This newsletter provides

information on the Wide Area

Augmentation System (WAAS) and the

Local Area Augmentation System

(LAAS), and initiatives associated with

the implementation of satellite

navigation into the National Airspace

System (NAS).

In this issue:

Garmin Offers WAAS LPV

Receiver...............................1

WAAS - A Pilot’s View........1

Additional WAAS

Reference Stations in

Alaska.................................2

Mexico WAAS Project........3

Proyecto WAAS En

Mexico.................................4

FAA LAAS and European

GBAS Working Group

Meeting................................5

New WAAS LPV Receiver - Garmin GNS 480
2

There are some minor discrepancies with basic GPS. First,

the altitude function doesn’t match with my altimeter. Second, doing Receiver Autonomous Integrity Montoring (RAIM)

predictions is a minor nuisance. Third, GPS approaches seem

to have high minimums. Fourth, I can’t file an airport Instrument Flight Rules (IFR) with only a GPS approach as an alternate. If WAAS could fix some of these, I’d be happy. I already know that GPS improves my navigational accuracy, allows more direct routing and improves safety by both allowing

me to spend more time with my head out of the cockpit and

by improving my situational awareness. So what am I really

going to gain by adding WAAS?

The fact is that WAAS fixes all of these, and it does even

more. WAAS improves both horizontal and vertical accuracy

of GPS to about two meters. Second, WAAS improves upon

the integrity of GPS, and obviates the need for RAIM. Third,

WAAS has introduced a new approach called LPV, which has

minimums as low as 250 feet and provides an Instrument Landing System (ILS)-like glide slope. Fourth, I can now use an

airport as an alternate even if the only approach is GPS. I

can’t use the LPV minima-line, but I can use the GPS minimums. In addition to LPV approaches, I can use WAAS to

fly lateral navigation/vertical navigation (LNAV/VNAV) approaches to the VNAV minimums. This provides me with

about 800 new approaches in the United States, and the number is growing rapidly. I will probably find an additional 100+

approaches in the next year.

Probably, the biggest benefit of WAAS will be what it allows

me to do in the near future. The FAA is redesigning much of

the airspace system, and it is also moving toward a system

based upon Required Navigational Performance (RNP). This

means that my aircraft will have to meet specific navigational

accuracy capabilities for me to be allowed to operate in different classes of airspace or fly certain arrivals, departures and

approaches. While aircraft can meet the RNP requirements

through a variety of means, WAAS offers the least expensive

means—especially when compared to the cost of a flight management computer and integrated dual DMEs to update it.

I’ve been around long enough to be able to recognize trends—

especially a trend that has had this kind of money spent on it.

The government has spent money putting up dozens of navigation satellites, and continues to develop and launch new

navigation satellites. It isn’t putting up new VORs, and it

certainly isn’t putting up more Non-Directional Beacon

(NDBs). In fact, they are talking about decommissioning many

of the older navaids, so the priority will be on satellite-based

navigation aids. WAAS is in service and the FAA has committed to publishing 100 new LPV approaches this year (FY05)

and 150 new approaches in FY06. So my choice is whether to

become an early user, or wait until I’m facing extinction by

not being able to fly to my intended destination because I

lack the equipment. Cost isn’t really an issue, because most

GPS receivers can be upgraded for a reasonable charge.

So what does WAAS mean to me as a pilot? It means more

safety, fewer restrictions in flight planning and destination

selection and the proven capability of being able to navigate

my aircraft with an accuracy of a couple of meters for the

entire duration of my flight. For a guy who used to navigate

by reading the town name off the local water tower, I think

WAAS is wonderful!

Additional WAAS Reference

Stations in Alaska

by Wally Peterson, GPS TAC/FAA ATO-W

The Wide Area Augmentation System (WAAS) enhancement

program completed a milestone at the end of September with

the physical installation of four new WAAS Reference Stations (WRS) in Alaska. This is the culmination of a lengthy

process starting from site selection, through site surveys and

WAAS Reference Station in Barrow, Alaska
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finally, the physical installation and checkout of the equipment. The process of installation was a team effort utilizing

resources from the Federal Aviation Administation (FAA)

Alaska Region, FAA National Airspace System Implementation Center (ANI), FAA Technical Center, FAA WAAS Product Team, and Raytheon Company.

The WRSs installed in Alaska are comprised of all new equipment, designed by Raytheon Company, to support the planned

improvements to the WAAS. These installations will be operational in the WAAS in December 2005 and are located at

Barrow, Bethel, Fairbanks, and Kotzebue. Prior to the operational date, the WRSs will be utilized to evaluate the safety

implications of the installations on the WAAS signal-in-space

and to support software development and integration. Additionally, changes to the corrections and verifications subsystems

and the operations and maintenance subsystems will be completed in order for the WAAS to utilize the new WRSs. Once

those efforts are completed, the change process allowing the

integration of the sites into the WAAS is complete and the

FAA technicians are trained to operate and maintain the sites,

the sites will be commissioned and cut into the WAAS.

Mexico WAAS Project

by Joaquin Diaz Garcia, SENEAM

Translation to English by Jorge Boubion, WAAS Operations

Lead, Pacific Desert Systems Management Office

The increasing demand of air traffic and how to satisfy this

demand has been one of the principle goals of the International Civil Aviation Organization (ICAO). The ICAO Transition and Implementation Plan for CNS/ATM system integration supports a global, safe and standardized air space. The

ICAO plan utilizes high-precision equipment and new air traffic procedures to increase this air space capacity.

Mexico’s Servicios a la Navegación en el Espacío Aéreo

Mexicano (SENEAM) is an enthusiastic participant in this

transition to a global air space. It is important to emphasize

that GPS data collected by the Instituto de Geofísica

(www.igeofcu.unam.mx) was used to model ionospheric behavior as it relates to WAAS performance requirements.

ICAO’s Global Navigation Satellite System (GNSS), enhanced

with an open-architecture digital telecommunications network,

satisfies the availability, reliability, precision and integrity requirements for aviation.

The GNSS utilizes the augmented Global Positioning System

(GPS) to meet the requirements for aviation. For more than a

decade, the research and development of the GNSS has culminated with the certification and acceptance in the United

States of the Wide Area Augmentation System (WAAS) on

July 10, 2003.

Research and development in the early 1990s created the

National Satellite Test Bed (NSTB) and it was considered to

be a prototype of the WAAS. In 1999, Mexico’s SENEAM,

under a technical cooperation agreement with the Federal

Aviation Administration (FAA), decided to install three NSTB

reference stations in Mexico. In that same year, SENEAM and

FAA technical personnel completed the installation and these

reference stations became operational at Mazatlán, Mexico

City and Mérida airports.

On March 21, 2001 (Spring Equinox), near-precision flight

tests were conducted at Mérida Airport with intent to evaluate the feasibility of approaches using GPS in Mexico. The

March 21 date was chosen because it is at this time when solar

activity is at its greatest and greatly effects the propagation of

electro-magnetic signals through the ionosphere. Modeling

ionospheric behavior during solar storms was fundamental to

the development of the WAAS. Since 2001, NSTB reference

stations have been critical and important in collecting GPS

data. Data from these test reference stations is used to model

ionospheric behavior in the airspace. No GPS data was collected between January 2000 through March 2001.

SENEAM searched science and educational institutions in

Mexico for possible sources of empirical GPS data that could

benefit air navigation. The Instituto de Geofísica, Universidad

Nacional Autónoma de México, provided this data with promising results.

The Instituto de Geofísica has over one dozen GPS stations.

Data received from these stations is used for studies within
4

the different regions of Mexico in geophysics and tectonics to

define reference marks of earth deformations and movements.

The contribution of the Instituto de Geofísica has been important and is currently being analyzed by the Jet Propulsion

Lab of National Aeronautics & Space Administration (NASA).

In accordance with the agreement between SENEAM and

FAA, three WAAS reference stations (WRS) are scheduled to

be installed in 2005. The WRSs will be located at México

City, Mérida and Puerto Vallarta airports and should be ready

for operational use in 2006. In 2006, two additional WRSs

are scheduled to be installed and will be located at Tapachula

and La Paz airports. They should be operational in 2007. The

WAAS service volume coverage is expected to extend with the

installation of these WRSs and is predicted to benefit the

GNSS for users and service providers.

Proyecto WAAS En Mexico

by Joaquin Diaz Garcia, SENEAM

La creciente demanda del tráfico aéreo y como satisfacerla ha

sido uno de los principales retos de la Organización de

Aviación Civil Internacional. Su Plan de Transición e

implementación para la migración a Sistemas CNS/ATM

pretende un espacio aéreo global seguro y uniforme utilizando

equipos con mayor precisión y nuevos procedimientos

mediante los cuales se incremente la capacidad de dicho

espacio.

México, a través de Servicios a la Navegación en el Espacio

Aéreo Mexicano (SENEAM), ha sido un entusiasta

participante en esta transición. Es interesante resaltar la

utilización de los datos GPS del Instituto de Geofísica

(www.igeofcu.unam.mx) dada la convergencia de su área de

interés, el comportamiento ionosférico como precursor

sísmico, con el requerimiento del WAAS de modelar dicho

comportamiento ionosférico.

Es por todos conocido que la Organización de Aviación Civil

Internacional (OACI), planea usar un Sistema Mundial de

Navegación Satelital (GNSS), integrado con una red de

telecomunicaciones basada en tecnología digital y arquitectura

abierta que satisfaga los requerimientos de la aviación en

cuanto a disponibilidad, continuidad, precisión e integridad.

El Sistema de Navegación y Vigilancia referido prevé utilizar

el Sistema Global de Posicionamiento (GPS) mejorado para

cumplir con los requerimientos que exige la aviación. La

investigación y desarrollo de este Sistema por mas de una

década ha culminado con la certificación y aceptación en

Estado Unidos, del Sistema Mejorado de Área Amplia (WAAS)

realizada a principios de este año.

A principios de los 90’s y con propósitos de investigación y

desarrollo, fue creada la plataforma de Navegación Satelital

(NSTB), o prototipo del Sistema WAAS. En 1999 México, a

través de Servicios a la Navegación en el Espacio Aéreo

Mexicano, (SENEAM) bajo un acuerdo de cooperación técnica

con FAA, dispusieron instalar 3 estaciones de referencia en

México. En ese mismo año se capacitó personal técnico de

SENEAM, el cual conjuntamente con personal de FAA, llevó

a cabo la instalación y puesta en operación de las Estaciones

de Referencia en los Aeropuertos de Mazatlán, México y

Mérida.

En Marzo 21 DEL 2001 (Equinoccio de Primavera), se

realizaron en el Aeropuerto de Mérida pruebas en vuelo con

aproximaciones de precisión WAAS/NSTB. Los vuelos fueron

programados en esa fecha para tener las condiciones de mayor

afectación a la propagación de las señales electromagnéticas y

así evaluar su factibilidad de operación en México. Los

resultados confirmaron la factibilidad de utilizar el Sistema

WAAS en el Espacio Aéreo Mexicano, con la Instalación de

las correspondientes estaciones de referencia. Es fundamental para la operación del Sistema WAAS, modelar el

comportamiento Ionosférico, aun en condiciones de

comportamiento crítico para la propagación de Ondas

Electromagnéticas, como sería durante períodos de tormentas

solares. Para lo anterior, la operación de las Estaciones de

Referencia de la plataforma de prueba ha sido importante

contándose con datos recibidos de GPS permitiendo conocer

el comportamiento de la Ionosfera, en el Espacio Aéreo

Mexicano desde 2001, sin embargo un periodo crítico e

importante para el análisis, y del cual no se contaban datos

GPS es de Enero 2000 a Marzo del 2001.

Por lo anterior SENEAM, se abocó a indagar en Empresas e

Instituciones Educativas las posibles fuentes de datos GPS,

que pudieran compartir en beneficio de la Navegación Aérea.

Con ese propósito se contacto al Instituto de Geofísica,
5

perteneciente a la Universidad Nacional Autónoma de México,

con resultados positivos.

El Instituto de Geofísica posee mas de una docena de

Estaciones GPS que utiliza como herramienta de algunas de

sus áreas de Investigación y mediante las cuales, con la

información obtenida realiza estudios de Geodinámica y

Tectónica para definir el marco de referencia de deformaciones

y movimientos corticales que experimentan las diferentes

regiones de México, causadas por su entorno Geológico como

son limites convergentes de placas, Vulcanismo, Geofísica

Marina, etc.

La contribución del Instituto de Geofísica, ha sido importante

y actualmente sus datos compartidos se encuentran

analizándose en el Laboratorio JPL de la NASA.

Conforme a lo acordado entre FAA y SENEAM, se pretende

instalar tres estaciones de referencia durante 2005 (México,

Mérida y Puerto Vallarta), para su operación en 2006, y dos

estaciones (Tapachula y La Paz), en 2006 para su operación en

2007. Con la Instalación de estas Estaciones se pretende extender la cobertura actual del Sistema WAAS, con los

consecuentes beneficios que el Sistema Global de Navegación

Satelital prevé para sus usuarios y proveedores del servicio.

FAA LAAS and European

GBAS Working Group

Meeting

by Dieter Guenter, GPS TAC/FAA ATO-W

In December, the Federal Aviation Administration (FAA) Local Area Augmentation

System (LAAS) program team hosted the

most recent meeting of the Ground Based

Augmentation System (GBAS) Working Group. The European GBAS working group was established several years ago

as forum for the development of GBAS technology, for the

evaluation of GBAS benefits, and for the development of a

GBAS implementation strategy for Europe. The last meeting

was hosted by EUROCONTROL at the Eurocontrol Technical Unit in Bretigny, France in April 2004.

As a result of the FAA decision in 2004 to move LAAS to a

research and development program, European service providers were prompted to re-evaluate their GBAS activities. Many

of the service providers had aligned their national GBAS programs with the FAA LAAS program schedule and were planning on LAAS being available in 2006. Representatives from

the FAA’s LAAS team agreed to provide information on current LAAS plans and activities at the December GBAS meeting to support Europe in the re-evaluation of their plans.

At the meeting, the FAA team reported substantial progress

in several areas of LAAS development. Most significant

progress was made in two of the most demanding technical

areas of the program - ionospheric threat definition and monitoring, and LAAS ground error overbounding and monitoring analysis. Both these technical risk areas are managed by

implementing proper mitigation options. Currently, the ratings for both risks have been reduced from high to medium.

In the area of ionospheric threat definition, a deficiency in

integrity monitoring was identified due to recent developments

in the ionospheric behavior studies of other programs.

A LAAS Ionosphere Working Group was formed with participation from research scientists from FAA, Honeywell, and

Stanford University to address this issue. The working group

successfully modeled the worst-case ionospheric threat to LAAS

and gained consensus between the stakeholders in the government and in the industry. The working group also proposed different ways of monitoring for the ionospheric threat

without any changes to the existing safety requirements and

standards. One such method of ionospheric threat monitor

implementation is already mature, the others are under investigation.

The other risk area where major progress has been made is

LAAS ground error overbounding and monitoring analysis.

Ground errors need to be defined and bounded for the system to achieve required safety objectives such as continuity

and integrity. Previously, lack of data and analysis of confidence marred establishment and monitoring of this most critical safety parameter in

the system. Now, through the use of large

amounts of data collected at the FAA Tech-
6

Federal Aviation Administration

800 Independence Avenue, SW

Washington, DC 20591

http://gps.faa.gov

nical Center using the sophisticated LAAS Test Prototype and

combined with brain power from the FAA, Ohio University,

Stanford University, and Honeywell, a consensus has been

reached on a road map to solve this problem. A methodology

has been established to overbound and monitor the ground

errors with sufficient confidence. Other issues related to the

problem, such as the false alarm rates, are currently under

investigation. The progress made by the FAA team and

Honeywell was considered an important improvement in the

development of GBAS CAT I technology and encouraging

information for nations with existing prototypes and funded

GBAS programs.

Discussions and presentations from the individual service providers showed the effect that FAA program uncertainties have

had on the national strategy of many service providers. Most

of these service providers still consider GBAS to be the precision approach technology of the future. They continue to support GBAS activities either through CAT II/III standards development or through plans with their national regulatory

agencies and European airlines for early operational approval.

Especially interesting were the plans of Aeropuertos Espanoles

y Navegación Aérea (AENA) in Spain with national flight inspection aircraft and Air France at Malaga airport and their

desire to implement GBAS CAT I as soon as possible. In

Germany, Deutsche Flugsicherung GmbH (DFS) is working

with Lufthansa at Frankfurt and Bremen airports to achieve

early operational approval for GBAS CAT I systems and is

also focusing on the development of a concept of operations.

Skyguide of Switzerland has already changed their original

GBAS implementation plan due to FAA program changes and

has instead acquired a high cost “End Fire” Instrument Landing System (ILS) system at Zurich airport. Brazil plans were

presented by the FAA and are similar to other service provider plans with emphasis on an early operational approval of

GBAS technology.

EUROCONTROL outlined some related European GBAS

activities and presented the Eurocontrol Landing and Take

Off work program (LATO). The outcome of the

EUROCONTROL xLS business case showed that an overall

transition from ILS to either Microwave Landing System (MLS)

or GNSS Landing System (GLS) was not cost efficient for Europe, however, local requirements could drive the need for

either MLS or GLS. Consequently EUROCONTROL support will continue for the GBAS development for the European states that are willing to implement GBAS operationally

and technically. Germany, Spain, Switzerland, France and Italy

remain engaged in GBAS activities at different levels, while

the UK is focusing on MLS implementation.

This meeting also included participation of users/potential

future customers (Continental Airlines) and aircraft manufacturers (Boeing and Airbus). Their involvement reinforced

user support for GBAS, which remains very strong and visible

in the involvement of different airlines in the US and Europe. Boeing and Airbus presented a strong common GLS

position, outlining the need for quick GBAS implementation

due to the ongoing certification activities in the US and Europe and a window of opportunity regarding avionics finalization for the Boeing 7E7 and Airbus A380, respectively. They

outlined the urgent need for operational GLS experience, starting with CAT I systems, and reiterated the need for clear policy,

planning, and realistic deadlines.

The technical, operational and programmatic discussions

proved to be a valuable information exchange between participating national and international organizations and are

considered an important vehicle for coordinating activities

outside of the ICAO or RTCA-JAA meetings. Overall, it was

agreed that the GBAS working group and the FAA LAAS team

should continue their close coordination. In addition, more

detailed areas of cooperation were outlined, which include

ionosphere, GBAS safety case, GBAS CAT III concept of operations and GBAS early operational activities. Concurrently,

national representatives will continue assessing the impact of

FAA program decisions on their national GBAS plans. The

next GBAS meeting is planned for June 2005.