U N I V E R S I T Y  O F  C O L O R A D O 

LECTURE OUTLINES


ASEN 5190

Course Overview

Instructors

Syllabus & Schedule

Labs

Notes

Links

 

Lecture 1 – GPS Technology Lab Overview 8/22/05

�.                       Course overview & introductions

�.                       Book logistics

�.                       Lab scheduling

�.                       Expectations

�.                       Questions: What do you hope to get out of this class?

�.                       Reading: Chapter 1

Lecture 2 – Introduction to GPS 8/26/05

�.                       History

�.                       Overview of how it works

�.                       Space Segment

�.                       Control Segment

�.                       User Segment

�.                       Questions: What are the advantages/disadvantages of satellite-based radionavigation systems as compared to terrestrial radio or inertial navigation systems? In what ways is a radionavigation system the same as a communication system?  In what ways is it different?

�.                       Reading: Chapter 2.1-2.2

Lecture 3 – Fundamentals of GPS 8/29/05

�.                       Overview

�.                       Coordinate Systems

�.                       Time Systems

�.                       Ranging Measurements

�.                       Position Solutions

�.                       Questions: Do navigation satellites really require high precision clocks?  What is the role of each of the 3 segments of GPS?

�.                       Reading: Chapter 2, 3.1, 3.2

Lecture 4 – GPS Orbits & Positioning Errors 9/2/05

�.                       Keplerian Orbits

�.                       Orbital elements

�.                       Broadcast almanac and ephemeris

�.                       DOPS & error measures

�.                       Questions: Why were medium altitude orbits selected for GPS?  How many satellites are currently operating on-orbit?

�.                       Reading: Read 3.3-3.4

 

Monday 9/5 No Class – Labor Day

Lecture 5 – Lab 1 Discussion 9/9/05

�.                       Examples of student data from Lab 1

�.                       Discussion of visibility findings

�.                       Use of Garmin 12 XL receivers

�.                       Error ellipses

�.                       Measurement sensitivity matrix (H)

�.                       GDOP and other DOPS

Lecture 6 – GPS Measurements & Errors 9/12/05

�.                       Pseudorange Measurements

�.                       Carrier Phase Measurements

�.                       Overview of GPS Measurement Errors

�.                       Selective Availability

�.                       Orbit Errors

�.                       Clock Errors and Relativity

�.                       Multipath Errors

�.                       Questions: Optimal geometry for GPS positioning has satellites distributed as widely as possible across the sky.  How do measurement errors affect the validity of this result?

�.                     Reading: Ch 4-4.2

Lecture 7 – Propagation Errors  9/16/05

�.                     Propagation through a medium

�.                     Ionospheric effects and correction models

�.                     Tropospheric effects and correction models

�.                       Questions: What is the ionosphere-free measurement combination for L1 and L5 measurements?  If L1, L2, and L5 are all available, is there any advantage to using all three or a particular combination of them to find the ionospheric delay?  Which pseudorange is best to use for positioning?  Carrier phase?

�.                     Reading: Ch 4.3 and 4.5

 

Lecture 8 – Differential GPS 9/19/05

�.                     Positioning

�.                     Differential GPS

�.                     Relative navigation

�.                     Local Area Augmentation Systems (LAAS)

�.                     Wide Area Augmentation Systems (WAAS)

�.                     Pseudolites

�.                     Reading: Ch 4.8, DGPS links on website

 

Friday 9/23 – No Lecture

Lecture 9 – GPS Signals & Codes 9/26/05

�.                       Overview of GPS signal structure

�.                       Digital code properties – length, chip rate, autocorrelation, cross-correlation

�.                       Boolean logic and circuit symbols

�.                       Tapped feedback shift register

�.                       Maximal length codes

�.                       Questions: What is a maximal length code? 

�.                       Reading: Ch 2.3, 7.4-7.5

Lecture 10 – GPS Code Properties 9/30/05

�.                     Gold Code properties

�.                     L2C, L5C

�.                     M-Code

�.                     dB’s

�.                     Code acquisition and tracking

�.                       Questions: How would the correlation function of a real signal differ from the idealized models?  How does the autocorrelation of the P-code differ from C/A?  Is it affected by the chip rate? 

�.                       Reading: Ch 7.6-7.7, 8.5

 

Lecture 11 – Frequency Domain Representations 10/3/05

�.                     Fourier Series for a Periodic Function

�.                     Square wave

�.                     Fourier Transform for a Pulse

�.                     Fourier Series for Pulse train

�.                     Here is the presentation – Fourier_Series2.ppt

�.                       Questions: What is the difference between a Fourier Series and a Fourier Transform?  What are the characteristics of the GPS signals in the frequency domain? 

�.                       Reading: Ch 7.1-7.3

Lecture 12 – Spread Spectrum 10/7/05

�.                     Modulation – AM, FM, PM

�.                     Mixers for modulation and up/down conversion

�.                     Spread spectrum signals

�.                     BOC spectrum

�.                       Questions: What are the advantages of using spread spectrum for GPS?  Why perform downconversion?  What are the advantages and disadvantages of a fast code rate compared to a slow code rate? 

�.                       Reading: Ch 7.3, http://www.sss-mag.com/ss.html

Lecture 13 – GPS Link Analysis 10/10/05

�.                     Satellite Transmit Power & EIRP

�.                     Space or path loss

�.                     Atmospheric loss

�.                     Receiver antenna

�.                     Received power

�.                     Noise, Noise temperature

�.                     Carrier-to-noise spectral density (C/No)

�.                     Signal-to-noise ratio SNR or Eb/No

�.                       Questions: How much antenna gain would you need to see the main lobe of a GPS signal on the spectrum analyzer?  What limits how narrow a bandwidth you can use to recover the GPS signal?

�.                       Reading: Ch 8.1-8.4

 

Friday 10/14 – No Class (Fall Break)

Lecture 14 – Antennas 10/17/05

�.                     Electromagnetic waves

�.                     What is an antenna?

�.                     Isotropic radiator

�.                     Directivity & beamwidth

�.                     Polarization

�.                     Efficiency

�.                     Gain

�.                     Antenna size, frequency

�.                     Insertion loss and bandwidth

�.                     Reciprocity

�.                       Questions:

�.                       Reading: Ch 8.1-8.4

 

Lecture 15 – Receiver Overview 10/21/05

�.                     Elements of a GPS receiver – preamp, downconverter, oscillator & frequency synthesizer, A/D, signal processor, navigation processor, user interface

�.                     Signal model

�.                     Downconversion

�.                     A/D conversion, Inphase and Quadrature sampling (I & Q)

�.                     Signal acquisition

�.                       Questions: At what point in the receiver is one satellite distinguished from another? 

�.                       Reading: Ch 9.1-9.2

 

Lecture 16 – GPS Control Segment Operations 10/24/05

�.                       2SOPS Mission

�.                       Satellite Command and Control

�.                       Space Segment

�.                       Operational Control Segment

�.                       Users

�.                       Navigation Tactics & Payload Analysis

�.                       Mission Performance

�.                       Modernization

�.                       Satellite End of Life

 

Lecture 17 - Acquisition & Tracking  10/28/05

�.                       Questions: Which way should you search in Doppler to insure that you don’t miss the satellite in your search?

�.                       Reading: Ch 9.1-9.2

Lecture 18 – Code and Carrier Loops 10/31/05

�.                       Discriminators for DLL, FLL, PLL

�.                       Complex representation of signals – I/Q correlators

�.                       Early, prompt, and late

�.                       Questions:

�.                       Reading: Ch 9.1-9.2

Lecture 19 – Tracking Loop Models 11/4/05

�.                       Laplace Transforms

�.                       Block diagrams

�.                       1st and 2nd order systems

�.                       Noise equivalent bandwidth

�.                       Frequency driven tracking loops – continuous and discrete

�.                       Questions: How do you find the best bandwidth to use for tracking code and carrier?  Should the tracking loop follow the oscillator noise?

�.                       Reading: Ch 9.3, 9.6

Lecture 20 – New Signals   11/7/05

�.                       Guest speaker – Logan Scott, Wednesday 1pm in ECCR 245

�.                       GPS Modernized signals

�.                       Galileo

�.                       New L1Civil Signal redesign

Lecture 21 – GPS Positioning 11/11/05

�.                       Stand-alone positioning

�.                       Code-based DGPS

�.                       Carrier phase processing

�.                       Assisted GPS

Lecture 22 – Integration of GPS/INS 11/14/05

�.                       Assisted GPS (from last time)

�.                       Overview of inertial navigation systems – Gyros and accelerometers

�.                       Integration approaches – loosely coupled, tightly coupled

�.                       Use of Kalman filter for navigation – measurement update, time update

 

Lecture 23 – 11/18/05

�.                       Lab 5 Discussion and Demonstrations

�.                       Each group please come prepared to present 1 or 2 slides on your lab

�.                       Click here to see student presentations

Lecture 24 – 11/21/05

�.                       GPS-based attitude determination

�.                       Attitude representations

�.                       Antenna baselines

�.       &n