GPS Approach Lesson Plan

LPV16 at KDMW

Kelly Barrick

2/26/2024

GPS Approach Lesson Plan

• Completion standards
• Student understands how GPS systems work
• Student is familiar with GPS components
• Student is able to read an approach plate
• Student is able to brief the LPV16 approach at KDMW�
• Schedule - 30 min�
• Reference - FAA-H-8083-15B, Instrument Flying Handbook

- Bold method

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Agenda

• Introduction
• GPS Components
• RAIM
• WAAS
• GPS Approaches
• LPV Approaches
• How to Read an IAP
• LPV16 at KDMW

Introduction

• RNAV: “Area Navigation“ allows an aircraft to navigate between two points within the coverage zone of station-referenced navigation systems. 
• GNSS: This term is given to a worldwide position, velocity, and time determination system, that includes one or more satellite constellations, receivers, and system integrity monitoring.
• Four implementations of GNSS:
• USA: Global Positioning System (GPS)
• European Union: GALILEO
• Russia: (Global Orbiting Navigation System (GLONASS))
• China: BeiDou Navigation Satellite System (BDS)�
• The first GPS satellite was launched in 1978 to about 11,000 miles above the Earth. Initially, GPS was only available for government and military use. But by 1993, a full 24-satellite constellation became operational and was opened to public use.
• For an aircraft to get a 3D location, the GPS receiver must get a reliable signal from 4 satellites simultaneously.

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GPS Components

GPS consists of three distinct functional elements: space, control, and user.

1. Space Element: consists of over 30 Navigation Systems using Timing and Ranging (Navstar) satellites. The satellites in each plane are spaced 60° apart for complete coverage and are located (nominally) at about 11,000 miles above the Earth.
2. Control Element: consists of a network of ground-based GPS monitoring and control stations that ensure the accuracy of satellite positions and their clocks.
3. User Element: consists of antennas and receiver/processors onboard the aircraft that provide positioning, velocity, and precise timing to the user.

RAIM

• RAIM = Receiver Autonomous Integrity Monitoring.
• RAIM’s goal is to determine if a satellite is providing corrupted information.
• For receivers capable of doing so, RAIM needs six satellites in view to isolate a corrupt satellite signal and remove it from the navigation solution.

WAAS

• WAAS = wide area augmentation system
• WAAS is an air navigation aid developed by the FAA to augment the GPS with the goal of improving its accuracy, integrity, and availability
• Allows aircraft to fly more precise GPS instrument approaches 🡪 can give you position accuracy of better than 3 meters, 95% of the time!
• 4 step process:
• Reference Stations (WRS) receives GPS signal
• WRS data sent to Master Station (WMS) for correction
• WMS uplinks corrected signal to GEO Satellites
• GEO Satellites sends updated WAAS signal to aircraft

GPS Approaches

• LNAV – lateral guidance
• Lateral sensitivity does not increase as aircraft approaches runway
• LP – localizer performance
• Lateral-only WAAS guidance; sensitivity increases approaching runway
• LNAV/VNAV – lateral navigation/vertical navigation
• Linear throughout the final approach course
• Vertical guidance by WAAS or baro-VNAV system
• LPV – localizer performance with vertical guidance
• Lowest minimums of all GPS approaches
• Requires WAAS receiver

• WAAS/GPS based approach
• Non-precision
• APV – approach with vertical guidance
• WAAS system gives you lateral and vertical guidance down to a decision altitude (DA)
• Angular guidance – gets more sensitive closer to runway (similar to ILS)
• Lateral guidance – scaling transitions to linear scaling as you approach runway
• Can get you down to 200’ above touchdown, ½ mile visibility
• You must have a WAAS receiver to fly them (baro-aided GPS won’t work)

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LPV Approaches

How to Read an IAP Chart

Instrument Approach Procedure (IAP) charts are divided into various sections:

LPV16 at KDMW

“Circle around the plate”

• Verify approach name and expiration
• Tune radios
• Weather, Approach, Unicom
• Review Planview
• General route of course?
• FAF name?
• Review Profile view
• Starting altitude?
• FAF altitude?
• Select minimums
• DA/MDA? Circling?
• Review airport sketch
• Landing runway? Lighting?
• Verify missed approach
• Read notes

Check out the Aeronautical Chart User’s Guide!