How WAAS Works Part 2 of 4: Learn how WAAS interacts with GPS signals, what augmentation messages do, and how they're processed. Questions? Ask us! E-mail: * Message:

"How WAAS Works" Video Transcript

• How WAAS Works: WRS
• Augmentation Messages
• Uplink Stations
• GPS/WAAS Receiver Processing
• WAAS / LPV Approach Plate
• How is WAAS / LPV annunciated?
• WAAS FMS Navigation

My name is Gary Harpster and you're watching Understanding WAAS & LPV Part 2 of 4: How WAAS Works.

How WAAS Works: WRS

The signals from the GPS satellites are received across the North American System is a widely spaced Wide Area Reference Station. The WRS locations are precisely surveyed so that any errors in the received GPS signal can be detected.

Augmentation Messages

The GPS information that is collected by the WRS sites is forwarded to the WAAS master stations via terrestrial communication network. At the WMS, the WAAS Augmentation Messages are generated. These messages contain information that allows the GPS receivers to remove any errors in the GPS signal. Allowing for a signficant increase in location accuracy and reliability.

Uplink Stations

The augmentated messages are sent from the WMS to the uplink stations to be transmitted to the navigational payloads on Geostationary communications satellites.

GPS/WAAS Receiver Processing

The navigation payloads broadcast the augmentated signal on the GPS-like signal to your aircraft. The GPS WAAS Receiver processes that augmentated message as part as the estimated position.

WAAS / LPV Approach Plate

The LPV Approach on an Approach Plate is called out. You will see (see presentation slides)that it says WAAS Approach on it. So just like any approach, GPS approach, VOR Approach, ILS Approach. It calls out particular criteria. So you take the approach appropriate to that airport, channel it up in your receiver and fly the approach.

How is WAAS / LPV annunciated?

This shows (see presentation slides) how the LPV is annunciated. Depending on what type of EFIS you have, it may or may not be capable of displaying LPV technology and LPV annunciation. If not, external annunciation would be required.

WAAS FMS Navigation

On this slide (see presentation slides), it shows you what the WAAS approach looks like on the typical navigational receiver.

Contact Gary Harpster or a member of Duncan Aviation's Avionics Installation Sales team for more information.

Understanding WAAS/LPV Video Series

	WAAS Considerations: Introduction July 1, 2010 - Gary introduces the video series with a brief overview of key topics to consider if your aircraft isn't equipped with WAAS, including legacy interface problems, field approvals, annunciators, Next-Gen criteria, and how to determine if your aircraft is a candidate for an upgrade. » Watch "WAAS Considerations"
	Part 1: What is WAAS? July 8, 2010 - Find out how WAAS is a part of the FAA's Next-Gen initiative, the system network and coverage, and why installing WAAS-capable equipment doesn't mean you're ready to fly LPV approaches.. » Watch "What is WAAS?"
	Part 2: How WAAS Works July 15, 2010 - Learn how WAAS interacts with GPS signals, what augmentation messages do, and how they're processed. » Watch "How WAAS Works"
	Part 3: WAAS Benefits July 22, 2010 - Learn how WAAS changes navigational system accuracy, approaches, flexibility, precision, fuel savings and government and airport costs. Operational benefits and Next-Gen considerations are also discussed. » Watch "WAAS Benefits"
	Part 4: What is LPV? July 29, 2010 - Learn what LPV approaches are, how they benefit operators, and common equipment questions. » Watch "What is LPV?"

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