Guidelines for the use of GNSS in surveying and mapping

3 GNSS survey operations
3.1 Planning
After the tender process and award of contract for
the survey, the guidelines listed in Table F should
be used in the planning stage of a GNSS survey.
Any issues, problems or questions that arise can
then be resolved before the survey commences.
See Table F (p. 18).
3.2 Fieldwork and observations
After planning of the survey, the guidelines listed in
Table G should be followed during execution of the
fieldwork. These guidelines and explanations are a
summary of best practice. A full explanation and
more detailed coverage is given in Part 2.
See Table G (p. 19).
3.3 Data processing
Table H sets out guidelines for the processing of
GNSS survey data and is a summary of section 7.5
in Part 2.
3.4 Co-ordinate systems
The selection of an appropriate co-ordinate system
and reference control point will be aided by the
guidelines listed in Table I. These are applicable for
use of differing co-ordinate systems in GNSS
surveys. The guidelines in Table I (p. 21) summarise
section 6 in Part 2.
3.5 Reporting
Table J (pp. 22–23) sets out guidelines to be used
when producing the report for a survey which has
included an element of GNSS measurement.
3.6 Essential considerations for GNSS
surveys
It is recommended that surveyors are appropriately
trained and experienced in recognising the
difficulties involved in GNSS surveys. When the
requirements of a client are assessed, it is
important that any difficulties unforeseen by the
client are communicated to them. In extreme cases,
the specification for the GNSS part of the survey
may have to be altered to allow for these
difficulties. Typical difficulties include:
+ atmospheric refraction – ionospheric and
tropospheric problems
+ multipath
+ interference.
Guidelines to overcoming these issues are
considered in Tables K1 to K4 (pp. 24–27).
GUIDELINES FOR THE USE OF GNSS IN LAND SURVEYING AND MAPPING |17