【正文】 , cycle time, and consecutive time. The startstop time tool operates like a stopwatch: the user indicates through keystrokes both the start and stop time. PAVIC+ reads the time of the keystroke from a time stamp placed on the audio track and records cycle time tool is used when the same work sequence is repeated. The keystroke used to indicate the stop of an activity also indicates the start of the successive activity, which eliminates the need to press two keys simultaneously. The consecutive time tool is appropriate for a group of correlated activities, such as a crane serving multiple crews. Each activity is assigned a unique key that is struck when the activity ends. This keystroke indicates the stop of the associated activity and the start of the successive activity. Frank (2001) describes a very similar system used to extract information from digital presents and discusses the Digital Video Analysis Tool (DVAT) and notes that PAVIC+ was the basis on which DVAT was developed. DVAT is a software package specifically developed for stripping information from digital video. The extracted information can be used to generate crew balance charts or to develop input for puter simulation models. These traditional data collection methods have relied upon manual tools limited to the field of view of the observer. Researchers have turned to technology for tools that are both automated and not restricted to field of view. Kannan (1999) describes the use of onboard instrumentation systems for recording data from earthmoving operations. He used mechanical parameters recorded by the Vital Information Management System (VIMS) and the Total Payload Management System (TPMS) produced by Caterpillar to obtain operational data. Such systems place a virtual observer in the equipment, and thus the equipment is always in the virtual field of view.Kannan (1999) states that when using onboard instrumentation, the sensors must be able to detect a change in the status of the truck. This change in status indicates the start or stop of an activity. Kannan and Vorster (2000) state that mechanical parameters can be translated to production measures through the use of surrogate measures and protocol rules. Kannan (1998) describes the use of suspension strut pressure, gear control lever position,bed raise switch position, and speed to derive the duration of truck cycle ponents. Truck cycle ponents or activities are defined in terms of the parameters. It is evident from the literature reviewed that traditional datacollection methods are limited by the ability of an observer to instantaneously decide activity start and stop times within a narrow and static field of view. Modern techniques remove this limitation by using sensorbased datacollection techniques to identify key times through changes in sensor output. A thorough understanding of the methods for reviewing, reducing, and analyzing GPS data from construction operations requires background knowledge of how and what data are collected.Data Capture An automated data capture system based on GPS technology was used to record the raw data at a userspecified time interval, including date, time, velocity, and horizontal position. The system consists of a data box, junction box, and sensor pack and was developed based on field evaluations of mercially available systems. The data acquisition and storage box is a weathertight enclosure that houses the system circuitry and the CompactFlash media on which the data is stored. The sensor pack consists of a Garmin GPS35 LVC receiver and a Vector 2X magnetic pass manufactured by Precision Navigation, Inc. In addition to the GPS and pass, the system has been developed such that additional analog and digital sensors can be incorporated into the system for future research. The junction box serves as a central location for all electrical connections to be made. Power is made available in the box at 5 V for any additional analog sensors incorporated into the system. Data are recorded in ma delimited ASCII text format, with a separate data file for each day of collection to ensure files of a manageable size. The parameters recorded by the system include unit identification number, date, UTM time, latitude, longitude,velocity, type of GPS fix, output from the five analog and eight digital sensors, and direction of travel from the pass. Preliminary ReviewA tradeoff exists between the volume of data recorded and the level of detail provided by the data. Large volumes of data are produced when recorded at a time interval sufficiently short to facilitate operations analysis. The several thousand records produced daily on each machine must be reduced to the relatively few key records necessary to calculate activity times. The large volume of data dictates that the data reduction process be automated.The format of the data, a text string repeatedly recorded at aset time interval, is conducive to analysis in a spreadsheet environment supported by capable graphics. Microsoft Excel was chosen as the data processing engine as it is a widely used and recognized program already familiar to many potential users, thereby minimizing or eliminating the learning curve. Excel is a mon and robust spreadsheet application that can be automated through the Visual Basic for Applications (VBA) language and provides the means to graphically represent data.Processing the collected data for evaluation and reduction is performed in three steps: the data into Excel。 recorded horizontal position from geodetic to planar coordinates。 and graphical representations of the data. These three steps have been automated using VBA code, and this routine is available from the system user interface, provided as Fig. 1. The process of importing, converting, and graphing is executed by selecting the Import Text option, which allows the user to point to the desired data file.Once the file is identified, the data are imported into