Home About Browse Search
Svenska


Averaging absolute GPS positionings made underneath different forest canopies

a splendid example of bad timing in research

Holmström, Hampus (2001). Averaging absolute GPS positionings made underneath different forest canopies. Umeå: (S) > Dept. of Forest Resource Management
(NL, NJ) > Dept. of Forest Resource Management
, Sveriges lantbruksuniversitet. Arbetsrapport / Sveriges lantbruksuniversitet, Institutionen för skoglig resurshushållning och geomatik ; 82
[Report]

[img]
Preview
PDF
537kB

Abstract

Dealing with data collection of natural resources for management planning purposes, there is an interest in capturing the spatiality, i.e. the geographical location of the features of interest. The Global Positioning System (GPS) provides a tool, both for navigation and positioning,
although not without limitations. Several sources of errors have impact on the positional accuracy. Differential GPS increases the accuracy but might in certain applications be
unavailable. Navigating in difficult terrain (e.g. mountain areas), where traditional maps give little or no guidance, highlights the benefits of GPS. By applying a not-so-advanced algorithm, arithmetical averaging, using absolute (non-differential) GPS measurements, it is possible to improve the positional accuracy. Initial horizontal mean errors are decreased by 50 % after approx. 10 minutes of active logging of singular GPS-positions and averaging
these. Improvement of the accuracy continues thereafter, although substantial improvements require long time of observation. The impact of the canopy was marginal, however assumed to cause longer time of logging in dense forests before a certain number of positions are obtained, compared to measurements made under a clear sky. However, it must be pointed out that the results are of somewhat doubtful value, since the conditions were drastically changed
when the intentional distortion of the GPS-signals (the Selective Availability, SA) was stopped. In the current situation, the different structure of the remaining errors leads to a limited use of averaging. This study was carried out just before the SA was stopped, which happened quite unexpectedly in May 2000.

Authors/Creators:Holmström, Hampus
Title:Averaging absolute GPS positionings made underneath different forest canopies
Subtitle:a splendid example of bad timing in research
Alternative abstract:
LanguageAbstract
EnglishUNSPECIFIED
Series/Journal:Arbetsrapport / Sveriges lantbruksuniversitet, Institutionen för skoglig resurshushållning och geomatik (1401-1204)
Year of publishing :2001
Number:82
Number of Pages:12
Place of Publication:Umeå
Publisher:Institutionen för skoglig resurshushållning, Sveriges lantbruksuniversitet
ISSN:1401-1204
Language:English
Publication Type:Report
Full Text Status:Public
Agris subject categories.:K Forestry > K01 Forestry - General aspects
U Auxiliary disciplines > U40 Surveying methods
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Forest Science
Agrovoc terms:forest inventories, global positioning systems, navigation, measurement, methods
Keywords:forest inventory , in field-applications, real time-solutions, spatial information
URN:NBN:urn:nbn:se:slu:epsilon-e-521
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-521
ID Code:8853
Department:(S) > Dept. of Forest Resource Management
(NL, NJ) > Dept. of Forest Resource Management
Deposited By: Bo Jonsson
Deposited On:24 May 2012 10:05
Metadata Last Modified:02 Dec 2014 10:50

Repository Staff Only: item control page

Downloads

Downloads per year (since September 2012)

View more statistics

Downloads
Hits