surveying iii (topographic and geodetic surveys) - Modern Prepper

(5) Accuracy of stop-and-go baseline measurements will usually well exceed 1 part in 5,000;therefore, third-order classification for horizontal control can be effectively, efficiently, and accuratelyestablished using this technique. For many projects, this order of horizontal accuracy will be more thanadequate; however, field procedures should be designed to provide adequate redundancy for open-endedor spur points. Good satellite geometry and minimum multipath are also essential in performingacceptable stop-and-go surveys.c. Kinematic Surveying. Kinematic surveying using differential carrier phase tracking is similar tostop-and-go kinematic and static differential carrier phase GPS surveying because it also requires tworeceivers recording observations simultaneously. Kinematic surveying is often referred to as dynamicsurveying. As in stop-and-go surveying, the reference receiver remains fixed on a known control pointwhile the roving receiver collects data on a constantly moving platform (such as a vehicle, a vessel, anaircraft, or a backpack). Unlike stop-and-go surveying, kinematic surveying techniques do not requirethe rover receiver to remain motionless over the unknown point. The observation data are laterpostprocessed with a computer and the relative vector or coordinate differences to the roving receiver arecalculated.(1) A kinematic survey requires two L1 receivers. One receiver is set over a known point(reference station) and the other is used as a rover (moved from point to point or along a path). Beforethe rover receiver can move, a period of static initialization or antenna swap must be performed. Thisperiod of static initialization is dependent on the number of satellites visible. Once this is done, therover receiver can move from point to point as long as satellite lock is maintained on at least fourcommon satellites (common with the known reference station). If loss of lock occurs, a new period ofstatic initialization must take place. It is important to follow manufacturers' specifications whenperforming a kinematic survey.(2) Kinematic data-processing techniques are similar to those used in static surveying. Whenprocessing kinematic GPS data, the user must ensure that satellite lock is maintained on four or moresatellites and that cycle slips are adequately resolved within the data recorded.(3) Differential (carrier phase) kinematic survey errors are correlated between observationsreceived at the reference and rover receivers, as in differential static surveys. Experimental test resultsindicate kinematic surveys can produce results in centimeters. Test results from an experimental fullkinematicGPS-S conducted by Topographic Engineer Center (TEC) personnel at White Sands MissileRange, New Mexico, verified (under ideal test conditions) that kinematic GPS surveying could achievecentimeter-level accuracy over distances up to 30 kilometers.d. Pseudokinematic Surveying. Pseudokinematic GPS surveying is similar to stop-and-gosurveying except that loss of lock is tolerated when the receiver is transported between occupation sites(the roving receiver can be turned off during5-31 EN0593