Guidelines for the use of GNSS in surveying and mapping
Guidelines for the use of GNSS in surveying and mapping
Guidelines for the use of GNSS in surveying and mapping
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Appendix E: Sample procedures relat<strong>in</strong>g to a<br />
<strong>GNSS</strong> survey<br />
These sample procedures are based on a simple<br />
method statement which could be given <strong>for</strong> a basic<br />
<strong>GNSS</strong> survey <strong>of</strong> an open site area, <strong>for</strong> example a<br />
road bypass site, where <strong>GNSS</strong> might be <strong>use</strong>d <strong>for</strong><br />
<strong>the</strong> whole work.<br />
Method statement – <strong>GNSS</strong> survey<br />
1 Site work<br />
1.1 Fur<strong>the</strong>r to a site reconnaissance any exist<strong>in</strong>g<br />
survey control will be <strong>in</strong>spected <strong>for</strong> stability <strong>and</strong><br />
mark<strong>in</strong>g.<br />
1.2 New control stations shall be <strong>in</strong>stalled, marked<br />
<strong>and</strong> prepared on station description sheets <strong>in</strong><br />
accordance with <strong>the</strong> specification. They shall be<br />
selected <strong>in</strong> <strong>GNSS</strong> friendly location – where <strong>the</strong>re<br />
exists a clear view <strong>of</strong> <strong>the</strong> sky to m<strong>in</strong>imise cycle<br />
slips, multipath <strong>and</strong> o<strong>the</strong>r <strong>in</strong>terference. Markers<br />
shall be road nails or earth anchors, as appropriate<br />
to <strong>the</strong> surface <strong>in</strong> which <strong>the</strong>y are <strong>in</strong>stalled.<br />
1.3 The follow<strong>in</strong>g equipment shall be <strong>use</strong>d <strong>for</strong> this<br />
survey … (state manufacturer, model/type)<br />
1.4 One <strong>GNSS</strong> base station shall be established at<br />
a central location <strong>in</strong> <strong>the</strong> survey area. This shall be<br />
<strong>in</strong> an area with an open view <strong>of</strong> <strong>the</strong> sky as<br />
described above <strong>in</strong> paragraph 1.2.<br />
1.5 As required, national control station(s) shall be<br />
observed or downloaded (via RINEX) to connect <strong>the</strong><br />
survey to <strong>the</strong> national grid system.<br />
1.6 Rov<strong>in</strong>g <strong>GNSS</strong> receivers will be established at<br />
o<strong>the</strong>r control stations <strong>for</strong>m<strong>in</strong>g a network around <strong>the</strong><br />
whole site. These shall log data <strong>in</strong> a static mode at<br />
a rate <strong>and</strong> duration to achieve <strong>the</strong> accuracy<br />
required.<br />
1.7 For <strong>the</strong> detail survey Real Time K<strong>in</strong>ematic<br />
(RTK) techniques shall be <strong>use</strong>d with<strong>in</strong> <strong>the</strong> above<br />
control network.<br />
2 Office work<br />
2.1 All <strong>GNSS</strong> survey data will be downloaded to<br />
<strong>of</strong>fice computers.<br />
2.2 Survey data process<strong>in</strong>g shall be carried out <strong>in</strong><br />
… (state name <strong>of</strong> manufacturer’s s<strong>of</strong>tware).<br />
2.3 Prior to process<strong>in</strong>g <strong>the</strong> control network,<br />
antenna heights shall be checked twice, once on<br />
import <strong>and</strong> once dur<strong>in</strong>g set up <strong>of</strong> process<strong>in</strong>g<br />
parameters. Basel<strong>in</strong>es shall be processed <strong>and</strong><br />
checked, loop closures shall be computed <strong>and</strong> a<br />
network adjustment shall be per<strong>for</strong>med. Coord<strong>in</strong>ates<br />
shall be output <strong>in</strong> <strong>the</strong> specified grid<br />
system with <strong>the</strong>ir precision values, toge<strong>the</strong>r with a<br />
list<strong>in</strong>g conta<strong>in</strong><strong>in</strong>g <strong>the</strong> full details <strong>of</strong> <strong>the</strong><br />
trans<strong>for</strong>mation <strong>and</strong> parameters <strong>use</strong>d.<br />
64 | GUIDELINES FOR THE USE OF <strong>GNSS</strong> IN LAND SURVEYING AND MAPPING
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