Practical Aspects of GPS Surveying
Photo of a geodetic benchmark in Honduras by Neal Lord
Department of Geoscience
Description of Course
Capsule statement of course
Global Positioning System surveying for
field applications: Signals. Coordinate systems. Datums. Cartographic
projections. Satellite orbits. Choosing hardware. Strategies for data
collection and analysis. Assessing uncertainty. Geocoding satellite
images. Integrating data with Geographic Information Systems. Emerging
- Calculus and/or elementary vector matrix algebra (Math 210, 211,
221 or equivalent) or consent of instructor
- Some experience with field mapping, navigation, or orienteering
- Familiarity with computers and/or high-level
programming/scripting languages is desirable.
- This course is NOT open to freshmen.
LEVEL OF COURSE: ADVANCED
- Civil and Environmental Engineering
- Geological Engineering
- Nelson Institute for Environmental Studies
Number: two (2)
7-week modular class beginning week 10.
(2.5 hours of lecture per week) x (7 weeks) + 2 x (4-hour field
exercises) = 25.5 hours of instruction
HOW TO REGISTER
GEOSCI 444-001 LEC (55572) Pract Appl of GPS Surveying
G L E 444-001 LEC (45403) Pract Appl of GPS Surveying
ENVIR ST 444-001 LEC (46124) Pract Appl of GPS Surveying
GEOLOGY 444-001 LEC (55572) Pract Appl of GPS Surveying
CIV ENGR 444-001 LEC (63268) Pract Appl of GPS Surveying
EXPANDED COURSE DESCRIPTION
- Positioning by multiple measurements of
- How does GPS work?
- How well does it work?
- Field mapping exercise: mapping and plotting a campus trajectory.
- Fundamental geodesy: ellipsoid, geoid, coordinates, datums,
- Review of Linear Algebra.
- Choosing a
surveying strategy: the tradeoff between cost and accuracy.
position from Code Observations (pseudoranges).
- Baseline computation
and M-files. Coordinate Changes and Satellite Position.
position from pseudoranges by two different methods. Clock offsets.
- Receiver position from phase observations.
- Kinematic and Rapid Static
- Real Time Kinematic surveying.
- Student presentations of
NEED FOR THIS COURSE
Many disciplines studying the Earth,
its environment and anthropogenic impact on them involve mapping or
sampling object in the field. The Global Positioning System allows
anyone equipped with a receiver (costing as little as $100) to estimate
their position coordinates (latitude, longitude and elevation) to
within 10 meters easily. With a more sophisticated instruments and
techniques, accuracies of better than 1 cm are possible. Applications
range from scientific (e.g., measuring tectonic plates as they move) to
the practical (“how do I get back to where I parked my car). If
students are to apply these techniques (or supervise others to do so)
in tomorrow’s world, they should understand the basic technical
underpinnings of GPS.
RELATIONSHIP TO OTHER UW-MADISON COURSES
The proposed new course is
complementary to, but distinct from, the following other courses, as
described in the supplementary material: Geography 370, Geography 377
(Introduction to Geographic Information Systems), Geological
Engineering 302 (Introduction to Electro-Optical and Microwave Remote
Sensing Systems), Geological Engineering 303 (Introduction to Remote
Sensing Digital Processing), Geological Engineering 304 (Remote Sensing
Visual Image Interpretation). On the other hand, I could not identify
any significant overlap with any courses in the undergraduate catalog
for 2005-2007. In assessing overlap, it is important to distinguish
between the two similar acronyms, GPS and GIS. The former stands for
Global Positioning System and is the topic of the proposed course. The
latter stands for Geographic Information System and is “downstream” in
the flow of information.
WILL THIS COURSE MEET A REQUIREMENT FOR
THE MAJOR IN YOUR DEPARTMENT OR ANOTHER DEPARTMENT?
YES, The course 444 does
count towards the 34 credits of course work in Geology and Geophysics
required for the major. It also counts toward the requirement of
12-15 credits of upper-level course work.
- To understand the current abilities, future potential, and
limiting factors of GPS surveys
- To master the criteria for choosing instrumentation hardware and
- To view practical examples applications of GPS surveying
- To apply GPS surveying to a practical example of interest
- To develop critical thinking skills, particularly in spatial
reasoning about quantitative data
- To develop the ability to work in a team, conceive and strategize
- To make judgments of the tradeoff between accuracy and cost
How will students be evaluated?
- Two problem sets involving data analysis with Matlab.
- One proposal for a project.
- Project, described above.
- No final exam.
- Seven-week modular course beginning week 10 of Spring Semester,
- Class will meet Tuesdays and Thursdays from 2:30 PM to 3:45 PM.
- Location for all class meetings is Room 1249 of Engineering Hall
- First meeting is 2:30 PM Tuesday March
- Field exercise I is from 1:00 to 5:00 PM Saturday April 10th, 2010
- Field exercise II is from 1:00 to 5:00 PM Saturday May 1st,
- Student presentations of projects are tentatively scheduled for
6:00 PM - 9:00 PM Tuesday May 11th, 2010.
- Office Hours: Tuesdays 4:00 to 5:00 PM in Room 1249 of
First Class; positioning
How does GPS work? How well does it work?
Geometry of the Ellipsoid; Geodetic Reference System; Geoid, Ellipsoid
and Datum; World Geodetic System 1984; Changing Datum
Preparing for a field survey
Field Exercise 1: Point Positioning with a single receiver
Introduction to Matlab: functions, scripts, plots, etc.
Review of Linear Algebra I: Vectors; Lengths and Dot Products; Planes
Review of Linear Algebra II: Matrices and Linear Equations; Heights by
least squares; weighted least squares
Choosing a surveying strategy: the tradeoff between cost and accuracy.
Expectations for student projects.
Receiver position from Code Observations
Precise point positioning for stationary receiver.
Field Exercise 2: Relative Positioning with three receivers
Precise point positioning for moving receiver
Relative positioning from phase observations for stationary receiver.
Rapid Static Positioning
Review Q & A.
Student presentations of surveying
Description of Project
Working in teams of two, the students
will use GPS receivers to perform a survey of interest to them. They
will then present the results of the survey to the class in a short,
15-minute oral presentation, as a team of two. Examples of projects
- Locations of parking spots for a certain type of vehicle (e.g.,
bicycle, handicap van, etc) available on campus at the time(s) of the
- Establishing a grid for environmental research on University
Lands, e.g. Arboretum
- Monitoring the trajectory, including estimates of velocity and
acceleration for recreational vehicles (e.g., bicycles, rowing shells,
sailboats, canoes, skateboards, cross-country skiing, etc.)
- Locating sampling, measurement, or observation points for
geologic, biologic or anthropological research project.
- Prior to undertaking the project, each student will write, as an
individual, a brief proposal of the problem to be addressed and the
technical approach for meeting it, including the trade-off between cost
- Locations for procuring pizza near campus. Click
here to download KMZ file for Google Earth.
- Locations of bike racks on campus. Click here to download
KMZ file for Google Earth.
||Strang, G., and K. Borre (1997),
Linear algebra, geodesy, and GPS, xvi,
624 p. pp., Wellesley-Cambridge Press, Wellesley, MA. [$65.00]
Warning: ordering this book through the usual channels may be slow.
Please allow enough time for delivery. If you are interested in taking
this course, please order the book in January! You can order it
directly from the publisher if you pay by check, but not credit card.
|Leick, A. (2004). GPS satellite
surveying. Hoboken, NJ, John Wiley.
Computer Aided Engineering Center
- The Matlab scripts described in Strang and Borre's textbook are
available free of cost from Strang and
Borre at http://kom.aau.dk/~borre/matlab/
- The Easy Suite - Matlab code for the GPS newcomer -- by Kai
Borre. Matlab code for reading RINEX files, determining a pseudorange
point position, calculating a carrier-phase baseline solution,
doing a Kalman Filter baseline solution, checking for cycle slips and
receiver clock resets, estimating ionospheric delay, plotting receiver
clock drift, and more... The technical paper which describes this
Matlab code is published in
GPS Solutions, Volume 7, Number 1, 2003, pp 47-51, "The Easy Suite -
Matlab code for the GPS newcomer" by Kai Borre. The Matlab code
is available at the author's website: http://www.gps.auc.dk/~borre/easy
- Download from here into your
own matlab directory
Google Earth Plus
Intended for personal use, Google Earth
Plus is an optional, upgraded version of Google Earth available for
$20. Why buy it? In addition to the basic features, Google Earth Plus
- GPS data import - read in tracks and waypoints from select GPS
- o Note 1:
Verified support for Magellan and Garmin devices only
- o Note 2:
Does not support export of tracks or waypoints to a GPS device
- Higher resolution printing (greater than screen resolution).
- Annotation – adds draw/sketch tools for richer annotations (can
be shared as KML).
- Data importer – read address points from .csv files.
To purchase Google Earth Plus, download
Google Earth at http://earth.google.com/earth.html . Then run Google
Earth and select "upgrade" from the "help" menu.
Excel or equivalent
For manipulating data tables in
Comma-Separated Values (CSV) format.
ARC GIS (optional)
Student license $100
It's a freeware (or donationware)
program that listens to NMEA GPS data
stream on a serial port and sends the data to a google earth .kml file
along with a .net service which lets google earth know when the file is
Neal has tried it with the Garmin Etrex and another GPS receiver and it
seems to work well with the free version of google earth. The
bridge software can be found at http://mboffin.com/EarthBridge
For tagging digital photos with GPS coordinates. No need for tricky
connections between the receiver and the camera. Clever! http://www.robogeo.com/home/
For translating data from one format to another....
Automatic Point Positioning Service (APPS)
Estimate position for a single GPS station with sub-meter precision
from a RINEX file containing (preferably dual-frequency) phase data
from a geodetic - grade GPS receiver. The receiver may be moving.
Online Positioning User Service (OPUS) - Static
Estimate relative position for a fixed station with with respect to
several stations of the CORS network in the US. Requires a RINEX file
containing dual-frequency phase data from a geodetic - grade GPS
receiver. Two different solutions are offered: Static (OPUS-S
Rapid Static (OPUS-RS
If you own a laptop, please bring it to
class on the meeting after the field mapping exercise.
If you own a digital camera with a USB
cable, please bring it to class for the field mapping exercise.
To be provided by the department of
Geology and Geophysics in cooperation with Geological Engineering
program. Click here
for more information about the GPS facility.
UW - Madison Campus
Driving from Berekeley campus to the SFO
Trimble 4600 LS
Neal was able to automate the Trimble
nav file to RINEX obs and nav files. The converted 4600LS files
are in a file called 4600Rinex.zip
We haven't looked to see if any of the data from the three receivers
Class Project: Presentations from Previous Years' Students
Power Point Files
KML and KMZ Files for Google Earth