Reduction of short-interval GPS data for construction operations analysis

The systems that historically have been used to collect data for time studies of construction operations are manual in nature and limited to the observer's field of view. Global Positioning System (GPS) technology incorporated into an onboard instrumentation system can be used to autonomously collect position and velocity data without the field of view limitation. Data must be collected at a short time interval to provide the level of detail necessary for operations analysis. Thus the issue becomes managing the data and identifying the relatively key records that mark the start and stop of activities. A field observer identifies the key times in real time with instantaneous decisions of when one activity stops and the next starts based on enormous volumes of visual information. This work developed a methodology for making equivalent decisions based on GPS data and presents the procedures developed to identify the key records necessary to calculate activity durations. A case study is used to illustrate application of the system to an earthmoving operation. Also, it is postulated how the information can be used in discrete event simulation.