GPS is not only TOMTOM

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GPS is not only TOMTOM
Isaac Troyano Pujadas ( IFAE Electronics
Depart. )IFAE Meeting, Bellaterra, November
13th 2008
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Contents

• History of GPS development.
• GPS Overview.
• Distance Calculation.
• Determining the Position.
• GPS Errors and Biases.
• GPS Applications.
• GPS Nowadays.
• GPS The Dark Side.
• GPS Hacking.
• Questions

Introduction
How does it work?
GPS utilities
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History of GPS development

• In the early 1960s, several U.S. goverment
  organizations were interested in developing a
  satellite system for three-dimensional position
  determination with the following attributes
  global coverage, continuous/all weather
  operation, ability to serve high-dynamic
  platforms, and high accuracy.
• Three satellite systems were explored before the
  GPS program by differents military services
  Transit, TIMATION and System 621B.
• In 1969, the Office of the Secretary of Defense
  (OSD) established the Defense Navigation
  Satellite System (DNSS) program to consolidate
  the independent development efforts of each
  military service to form a single joint-use
  system.
• The GPS program was approved in December 1973 and
  the first satellite was launched in 1978.
• In February 1994, the Federal Aviation Agency
  (FAA) declared GPS ready for aviation use.

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GPS Overview

• The system provides accurate, continuous,
  world-wide, three-dimensional position and
  velocity to users.
• The satellite constellation consists of 24
  satellites arranged in 6 orbital planes with 4
  satellites per plane (with a worldwide ground
  control that monitors their health/status).
• Two frequencies are used by the system, called L1
  (1,575.42 MHz) and L2 (1,227.6 MHz).
• GPS provides two separate service
• Standard Positioning Service (SPS).
• Precise Positioning Service (PPS).

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GPS Overview

• GPS consists of three segments
• Space segment.
• Control segment.
• User segment.

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GPS Overview

• Space Segment

Block IIIR satellite components.
GPS orbital planes around the Earth.
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GPS Overview

• Control Segment

Hawaii monitor station
Control segment stations
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GPS Overview

• User Segment

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GPS Overview

• Markets and applications
• Land
• LBS (Location-Based Services).
• AVLS (Automatic Vehicle Location Systems).
• Aviation
• ATC (Air Traffic Control).
• Space guidance
• Maritime

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Distance Calculation
Distance
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Determining Position

• 2-D Location

X
A
Y
R1
R2
TRACKING..
TRACKING..
B
R3
AMBIGUITY PROBLEM
Trilateration principle
User GPS receiver
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Determining Position

• 3-D Location

This links offers you the possibility to track
all of GPS system satellites
http//science.nasa.gov/RealTime/JTrack/3D/JTrack3
D.html
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GPS Errors and Biases

• The errors originating at the satellites include
• Ephemeris error.
• Selective availability.
• Clock error.
• The errors originating at the receiver include
• Clock error.
• Multipath error.
• System noise.
• Antenna phase center variations.

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GPS Errors and Biases

• Selective Availability
• For national security reasons, the military
  sometimes degrades the C-code signal. This is
  called selective availability.
• These errors are random.
• Errors be as high as 100 meters.

GPS after  cancellation of Selective
Availability (2001)
GPS with Selective    Availability (1997)
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GPS Errors and Biases

• Selective Availability

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GPS Errors and Biases

• WAAS (Wide Area Augmentation System)
• WAAS is a DGPS (Differential GPS) system that is
  a method to improve the positioning or timing
  performance of GPS using one or more reference
  stations at known locations, each equipped with
  at least one GPS receiver. The reference
  station(s) provides information to the end user
  via a data link that may include error
  corrections and integrity information.

WAAS ground network.
EGNOS ground network.
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GPS Applications
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GPS Applications

• There are lots of GPS applications that We may
  not know but are really
• important in so many fields. These not famous
  applications are
• Utilities industry.
• Forestry and natural resources.
• Precision farming.
• Civil engineering applications.
• Monitoring structural deformations.
• Open-pit mining.
• Land and marine seismic surveying.
• Airborne and seafloor mapping.

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GPS Applications

• Construction applications

• Utility mapping

• Forestry and precision farming

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GPS Applications

• GPS for monitoring structural deformations

• GPS for marine and land seismic surveying.

Akashi Bridge, Japan

• GPS for airborne mapping.

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GPS Applications

• GPS for airborne mapping.

LIDAR system mapping
Classical aribone photogrammery
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GPS Applications

• GPS for airborne mapping.

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GPS Nowadays
- Lunar GPS - GPS Deployed in War Against Bird
Flu - GPS Shoe - Track Blind People - New Quake
Prediction Methods - Dynamic urban map
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GPS The Dark Side

• U.S. Army GPS guided Weapons
• Excalibur projectiles.

• MOAB (Massive Ordnance Air Blast bomb).

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GPS Hacking

• GPS Spoofing

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Questions
that I could answerplease
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The End
Thanks for your time and attention