Causing Interference

GPS receivers require a line of sight to the satellites in order to obtain a signal representative of the true distance from the satellite to the receiver. Therefore, any object in the path of the signal has the potential to interfere with the reception of that signal. Objects which can block a GPS signal include tree canopy, buildings and terrain features.

Further, reflective surfaces can cause the GPS signals to bounce before arriving at a receiver, thus causing an error in the distance calculation. This problem, known as multipath, can be caused by a variety of materials including water, glass and metal. The water contained in the leaves of vegetation can produce multipath error. In some instances, operating under heavy, wet forest canopy can degrade the ability of a GPS receiver to track satellites.

Data Collection Techniques

There are several data collection techniques which can mitigate the effects of signal blockage by tree canopy or other objects. For example, many GPS receivers can be instructed to track only the highest satellites in the sky, as opposed to those satellites which provide the best DOP. Increasing the elevation of the GPS antenna can also dramatically increase the ability of the receiver to track satellites.

Unfortunately, there will be locations where GPS signals simply are not available due to obstruction. In these cases, there are additional techniques which can help to solve the problem. Some GPS receivers have the ability to collect an offset point, which involves recording a GPS position at a location where GPS signals are available while also recording the distance, bearing and slope from the GPS antenna to the position of interest where the GPS signals are not available. This technique is useful for avoiding a dense timber stand or building.

Further, a traditional traverse program can be used to manually enter a series of bearings and ranges to generate positions until satellite signals can again be received. This position data can then be used to augment position data collected with the GPS receiver.

This Content Originally Published by a land surveyor to Land Surveyors United Network

Views: 669

See Your Saved Posts Timeline

Where Thousands of Professional Land Surveyors, Students of Surveying and Educators are United through Collaborative Knowledge and Purpose.

Land Surveyor Forum - Community Discussions

Promark 3 GPS

Started by HAMZAT KAREEM Sep 29, 2017. 0 Replies

Glossary Guide to GPS Terms

Started by SurveyEarthinaDay. Last reply by Jaybird Mar 3, 2013. 1 Reply

GPS and Canopy

Started by SurveyEarthinaDay Mar 28, 2012. 0 Replies

OPUS Post Processing

Started by marcel milleur. Last reply by Ralph Perez Mar 30, 2012. 1 Reply

Home-Made GPS Receiver How-to

Started by ⚡Survenator⌁. Last reply by Jaybird Mar 3, 2013. 1 Reply

HTC Android GPS Apps

Started by Gary Breisch. Last reply by Gary Breisch Sep 22, 2011. 2 Replies

LightSquared GPS

Started by Scott D. Warner, PLS. Last reply by Scott D. Warner, PLS Jul 6, 2011. 5 Replies

Master Survey Programs

Started by RAJASEKARAN May 28, 2011. 0 Replies

Virtual Reference Station

Started by Ty Olinghouse. Last reply by Jaybird Mar 3, 2013. 1 Reply

Repeater Set Up?

Started by Paul Quagge. Last reply by Rich Maher Jan 19, 2011. 4 Replies

Repair and Replacement of TouchScreens

Started by Gary Breisch. Last reply by Gary Breisch Oct 25, 2010. 2 Replies


Started by Rich Maher Aug 10, 2010. 0 Replies

Previously Delayed GLONASS Satellites Launched

Started by Jim. Last reply by ronnie r. monilla Mar 5, 2010. 1 Reply

Take GPS Indoors

Started by Jim. Last reply by MARK GREGORY HILL Jul 30, 2010. 4 Replies

The Future Augmented

Started by Jim Mar 1, 2010. 0 Replies

geoid09 in gfs format file so I can SD card from PC

Started by Gary Breisch. Last reply by ronnie r. monilla Oct 5, 2010. 11 Replies

Tools,Apps and Quick Guides


Help With Survey Equipment

Social Support For Equipment

Surveying Video Categories

Surveying Photo Categories

United States Hub Forums

International Surveyor Hub Forums

Resources for Company Owners

Land Surveyor Social Media

Surveyor Resources Collections

Getting Started & Newsletter

Featured Land Surveyor Hubs

Surveyor Birthdays

© 2019   © Created by Land Surveyors United   Powered by

Badges  |  Contact LSU  |  Privacy Policy  |  Terms of Service

Site Explorer