Missouri Code of State Regulations › Title 20 - DEPARTMENT OF COMMERCE AND INSURANCE › Division 2030 - Missouri Board for Architects, Professional Engineers, Professional Land Surveyors, and Professional Landscape Architects › Chapter 18 - First and Second Order Horizontal and Vertical Control › Section 20 CSR 2030-18.050 - GPS Survey Guidelines

Current through Register Vol. 49, No. 14, July 15, 2024
PURPOSE: This rule is being amended to reflect
				  modern-day terminology and to be in compliance with HB 650, which was passed in
				  2013 and moves the State Land Surveyor's Office from the Missouri Department of
				  Natural Resources to the Missouri Department of Agriculture.
(1) Direct connections must be made to any
				adjacent observable National Spatial Reference System ( NSRS) and/or Missouri
				Geographic Reference System (MO GRS) station located five kilometers (5 km) or
				less from any new station.
(2) At
				least three (3) existing higher or equal order control points must be included
				in any proposed Global Positioning System (GPS) survey. Whenever possible,
				these should be three (3) three- (3-) dimensional control stations. Otherwise,
				two (2) sets of three (3) stations (three (3) two- (2-) dimensional horizontal
				stations and three (3) vertical control stations) must be used. These control
				stations should be chosen to be roughly equidistant on the periphery of the
				proposed project so that they enclose as much of the project as
				possible.
(3) Each new station to
				be established by the proposed GPS survey must be occupied at least two (2)
				separate times to enable proper checking of blunders (for example, incorrect
				point, setup errors, incorrect antenna heights). A separate occupation is one
				in which the antenna and its supporting device (tripod) have been taken down
				and set up again and the receiver restarted.
(4) Each station must be connected by
				simultaneous occupations ( baselines) to at least three (3) other stations in
				the network after outlier baselines have been rejected from the adjustment.
				Because it is generally easier to resolve the integer phase ambiguities over
				shorter base line, adjacent stations should be connected wherever
				possible.
(5) At least two (2)
				receivers must be used for relative positioning, although three (3) or more may
				be used for more efficient operation and increased station reoccupation and
				base line repeatability.
(6) A
				preanalysis should be performed to determine the minimum occupation time
				required to achieve the required standard of accuracy. In addition, the most
				appropriate satellites to observe at each site should also be selected for
				receivers unable to track all of the "visible" satellites. The preanalysis
				should be specific for carrier phase relative positioning.
(7) In order to meet second order accuracies,
				the carrier beat phase must be observed together with a time tag for each
				observation. Pseudo-range observations are not precise enough for control
				surveys and cannot be used.
(8) A
				detailed field log must be kept during observation taken at each station. At
				the very least the following information must be recorded:
(A) Universal Time Coordinated (UTC) date of
				observations;
(B) Station
				identification (name and number);
(C) Session identification;
(D) Serial numbers of receiver, antenna, and
				data logger;
(E) Receiver
				operator;
(F) Antenna height and
				offset from monument, if any, to one millimeter (1 mm). Note should be made as
				to whether the height is measured as a slant height or vertical
				height;
(G) Diagram illustrating
				stamping on the monument;
(H) Other
				stations observed during session;
(I) Starting and ending time (UTC) of
				observations;
(J) Satellites
				observed (including time of changes); and
(K) Completed field log data forms for each
				station occupation will be submitted either using those provided by the
				Missouri Department of Agriculture (MDA) or some other type containing all
				necessary information included on the MDA forms.