Abstract:
The preferred embodiment provides an ultra-wide band radio frequency real-time location system (RTLS), synchronized with a GPS location system to provide reliable location data, in and around concrete and steel superstructures to a BIM graphic model system, to gather and display worker location data and coordinate its display for use. The RTLS system continuously locates each participant through the use of an active RFID tag and/or GPS location device, which may be placed in a personnel badge and verified. The location system logs the participant locations in a database for real-time information retrieval and upload into a BIM display system.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to the building construction field. More specifically, the invention relates to integration of personnel tracking technologies into computer aided design software to identify the location and descriptions of construction workers. 
       BACKGROUND OF THE INVENTION 
       [0002]    Participants in the construction industry are constantly challenged to deliver successful projects despite tight budgets, limited manpower, accelerated schedules, and limited or conflicting information. The significant disciplines such as architectural, structural and plumbing and electrical must be coordinated to ensure efficiency. 
         [0003]    In the past, traditional building design was largely reliant upon two-dimensional drawings (plans, elevations, sections, etc.). However, modern building techniques include electronic building information modeling (BIM). BIM extends traditional building design beyond two dimensional drawings by providing electronic display of projects in three dimensions. BIM also covers spatial relationships between components and equipment installation, light analysis, geographic information, and quantities and properties of building components. 
         [0004]    The BIM concept provides a virtual construction of a facility prior to its actual physical construction, in order to reduce uncertainty, improve safety, and increase efficiency between sub-contractors. Sub-contractors from various disciplines can input critical information into the electronic model before beginning construction, with opportunities to pre-fabricate or pre-assemble some systems off-site. Waste can be minimized on-site and products delivered on a “just-in-time” basis rather than being stock-piled on-site. 
         [0005]    Quantities and shared properties of materials can be extracted easily. Project scope work can be isolated and defined. Systems, assemblies and sequences can be shown in a relative scale with the entire facility or group of facilities. BIM also prevents errors by enabling conflict or ‘clash detection’ whereby the computer model visually highlights to the team where parts of the building (e.g., structural frame and building services pipes or ducts) may wrongly intersect. 
         [0006]    The BIM concept involves representing a design as combinations of “objects.” The objects are typically undefined, generic or product-specific, solid shapes or void-space (like the shape of a room), that carry their geometry, relations and attributes. BIM design tools allow extraction of different views from a building model including objects for drawing production and other uses. These different views are automatically consistent, being based on a single definition of each object. 
         [0007]    For the professionals involved in a construction project, BIM enables a virtual information model to be handed from the design team (architects, surveyors, civil, structural and building services engineers, etc.) to the main contractor and subcontractors and then on to the owner/operator; each professional adds discipline-specific data to the single shared model. This reduces information losses that traditionally occurred when a new team takes ‘ownership’ of the project, and provides more extensive information to owners of complex structures. 
         [0008]    Use of the BIM concept extends beyond the planning, design and construction phases of a project, into the building life cycle, including uses in cost management, maintenance management, and facility operation. 
         [0009]    Many software programs are available for implementing a BIM concept. For example, Revit is available from Autodesk of San Rafael, Calif. Revit products use “.RVT” files for storing BIM models. Typically, a building model is constructed using 3D wireframe objects to create walls, floors, roofs, structure, windows, doors ductwork, electrical systems and other objects as needed. These 3D objects are generally organized “families” and are saved in appropriate files in a database, and to be later imported into a graphics display routine. 
         [0010]    A BIM “model” is typically a database file represented in the various ways which are useful for design work. Such representations can be plans, sections, elevations, legends, and schedules. Because changes to each representation of the database model are made to one central model, changes made in one representation of the model (for example, a plan) are propagated to other representations of the model (for example, elevations). Thus, drawings and schedules are always fully coordinated in terms of the building objects shown in drawings. 
         [0011]    Revit is only one of many varieties of BIM software which support an open XML-based IFC standard. This file type makes it possible to standardize workflow from different discipline consultants of a building project. 
         [0012]    Despite its advantages, the BIM concept of the prior art lacks the ability to track the real time location, expertise and other attributes of construction workers while they are on-site. “Collisions” of workers, including duplication of effort, attendance and allocation of resources are not integrated into the BIM concept. Applicant has recognized that a need exists to integrate worker tracking into the BIM concept to enable efficient allocation of various skill levels and disciplines of workers, and to identify and isolate problems such as choke points and excess labor force allocation. 
         [0013]    Applicant has also realized that no one tracking technology provides the dependability required to efficiently and reliably track and identify construction workers in a “live” building construction project. For example, large moving steel equipment, concrete, construction barriers, walls and high current electric devices such as air handlers and generators present on a live construction site all interfere to some degree with different tracking technologies at different times leading to failure. 
         [0014]    Despite their limitations, certain known technologies, when combined in a way described by Applicant, provide a novel solution to the problems of tracking and monitoring workers in a live construction project. 
         [0015]    One generally reliable tracking technology is a radio-frequency identification system (“RFID”). The RFID system uses electronic tags attached to the objects to be identified. 
         [0016]    The RFID tag stores information electronically in a non-volatile memory. The RFID tag includes a small RF transmitter and receiver. An RFID reader transmits an encoded radio signal to interrogate the tag. The tag receives the message and responds with its identification information. The response generally includes a unique tag serial number, and product-related information such as a stock number, lot or batch number, production date, or other specific information. RFID tags usually contain an integrated circuit for storing and processing information, modulating and demodulating a radio-frequency (RF) signal, collecting DC power from the incident reader signal, and other specialized functions and an antenna for receiving and transmitting radio frequency signals. 
         [0017]    Another known technology utilized by Applicant is the Global Positioning System or GPS. GPS provides location and time information in all weather conditions, anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. The system provides critical capabilities to military, civil and commercial users around the world. It is maintained by the United States government and is freely accessible to anyone with a GPS receiver. 
         [0018]    GPS receivers may include an input for differential corrections, using the RTCM SC-104 format. This is typically in the form of an RS-232 port at 4,800 bit/s speed. Data is actually sent at a much lower rate, which limits the accuracy of the signal. Receivers with internal DGPS receivers can outperform those using external RTCM data. 
         [0019]    Many GPS receivers can relay position data using the NMEA 0183 protocol. Although this protocol is officially defined by the National Marine Electronics Association (NMEA), references to this protocol have been compiled from public records, allowing open source tools like “gpsd” to read the protocol. Proprietary protocols also exist, such as the SiRF and MTK protocols. Receivers can interface with other devices using methods including a serial connection, USB, or Bluetooth. 
         [0020]    Civilian GPS devices provide latitude and longitude information, but, are not considered sufficiently accurate or continuously available enough (due to the possibility of signal blockage and other factors) to rely on exclusively to transmit highly accurate location information over a wide range of building construction equipment due primarily to interference from concrete and steel structures. 
         [0021]    The prior art has attempted several piecemeal solutions using either RFID or GPS, but none have attempted to combine positioning systems with a BIM model or other 3-D construction modeling systems and none have been completely satisfactory. 
         [0022]    For example, a known method for attaching an RFID tag to a worker is U.S. Pat. No. 8,191,292 to Cummings, et al. and U.S. Pat. No. 8,193,940 to Cummings, et al. Cummings, et al. disclose a device for displaying a recognition award includes a hard hat and an RFID tag located in a detachable holder on the hard hat. The device is used to provide a hands free way to position an RFID tag at an easily recognizable location on the construction worker. But, Cummings, et al. do not disclose a way to integrate the RFID tag with a BIM model. 
         [0023]    International Patent Publication No. WO 2006/013587 to Di Floriano describes a system including a plurality of sensors in a targeted area tracking a plurality of people carrying RFID devices. Di Floriano lacks the means or necessary systems to precisely track location, having only the ability to ascertain if a person carrying an RFID device is inside the targeted area. 
         [0024]    U.S. Patent Publication No. 2003/0013146 to Werb discloses a real-time locating system using a hybrid tag device having a dedicated location position system transmitter and a beacon transmitter. However, Werb does not disclose a way to input location information into a BIM system or to compensate for problems caused by obstructions on a construction site which interfere with the locating system. 
         [0025]    U.S. Patent Publication No. 2008/0312946 to Valentine, et al. proposes location based services including real-time tracking and information management for trade show events. Valentine, et al. do not describe a system for initiating tracking information with a construction BIM or a redundant position system which compensates for obstructions. 
         [0026]    U.S. Patent Publication No. 2008/0195434 to Broughton discloses a system for managing construction information based on a graphic model. Parameters such as installation status, cost status, and delivery times are associated in a database with a component in the graphical model. RFID tags are used to analyze the location of the object and its status as “installed” or “uninstalled.” However, Broughton does not disclose a way to integrate location information of personnel or construction workers into a BIM model nor does it provide a way to track or avoid constantly moving items (like workers) and compensate for building construction obstructions. 
         [0027]    Various embodiments disclosed address the need for worker location system for building construction projects which allows integration of personnel location information from synchronized RFID and GPS location systems and a coordinated upload of location information into a BIM format for display. Other disclosed embodiments provide synchronizing of location information to greatly improve the reliability of GPS information with RFID information. 
       SUMMARY OF INVENTION 
       [0028]    The preferred embodiment provides an ultra-wide band radio frequency real-time location system (RTLS), synchronized with a GPS location system to provide reliable location data, in and around concrete and steel superstructures to a BIM graphic model system, to gather and display worker location data and coordinate its display for use. 
         [0029]    The RTLS system continuously locates each participant through the use of an active RFID tag and/or a GPS location device, which may be placed in a personnel badge and verified. The location system logs the participant locations in a database for real-time retrieval and upload into a BIM display system. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    In the detailed description of the preferred embodiments, reference is made to the accompanying drawings. 
           [0031]      FIG. 1  is a block diagram of the preferred embodiment of the system disclosed. 
           [0032]      FIG. 2A  is a depiction of cell areas defined by a set of sensor nodes of a preferred embodiment of the system. 
           [0033]      FIG. 2B  is a block diagram of a sensor node of a preferred embodiment. 
           [0034]      FIG. 3  shows an exemplary deployment of disclosed system. 
           [0035]      FIG. 4  is a flow chart of a process of deployment of a preferred embodiment of the system disclosed. 
           [0036]      FIG. 5  shows a flow chart of a process of tag set up of a preferred embodiment of the system disclosed. 
           [0037]      FIG. 6  is a flow chart of the steps of use of a preferred embodiment. 
           [0038]      FIG. 7  is a flow chart of the process carried out by the RTLS control system of a preferred embodiment. 
           [0039]      FIG. 8  is a flow chart of the functions of a GPS module of the preferred embodiment. 
           [0040]      FIG. 9  is a flow chart of a synchronization method of a preferred embodiment of the system. 
           [0041]      FIG. 10  is a flow chart of the preferred embodiment of method of eliminating conflicting data and synchronization mismatches. 
           [0042]      FIG. 11  is a flow chart of a preferred embodiment of deriving a color transparency value. 
           [0043]      FIG. 12  is a graphic representation of display generated by the BIM modeler of a preferred embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0044]    It will be appreciated by those skilled in the art that aspects of the present disclosure may be illustrated and described herein in any of a number of patentable classes or context including any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof. Therefore, aspects of the present disclosure may be implemented entirely in hardware, entirely in software (including firmware, resident software, micro-code, etc.) or combining software and hardware implementation that may all generally be referred to herein as a “circuit,” “module,” “component,” or “system.” Further, aspects of the present disclosure may take the form of a computer program product embodied in one or more computer readable media having computer readable program code embodied thereon. 
         [0045]    Any combination of one or more computer readable media may be utilized. The computer readable media may be a computer readable signal medium or a computer readable storage medium. For example, a computer readable storage medium may be, but not limited to, an electronic, magnetic, optical, electromagnetic, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include, but are not limited to: a portable computer diskette, a hard disk, a random access memory (“RAM”), a read-only memory (“ROM”), an erasable programmable read-only memory (“EPROM” or Flash memory), an appropriate optical fiber with a repeater, a portable compact disc read-only memory (“CD-ROM”), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. Thus, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. 
         [0046]    A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. The propagated data signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code embodied on a computer readable signal medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, or any suitable combination thereof. 
         [0047]    Computer program code for carrying out operations for aspects of the present disclosure may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Scala, Smalltalk, Eiffel, JADE, Emerald, C++, C#, VB.NET, Python or the like, conventional procedural programming languages, such as the “C” programming language, Visual Basic, Fortran 2003, Perl, COBOL 2002, PHP, ABAP, dynamic programming languages such as Python, Ruby and Groovy, or other programming languages. 
         [0048]    Aspects of the present disclosure are described with reference to flowchart illustrations and/or block diagrams of methods, systems and computer program products according to embodiments of the disclosure. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable instruction execution apparatus, create a mechanism for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. 
         [0049]    These computer program instructions may also be stored in a computer readable medium that when executed can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions when stored in the computer readable medium produce an article of manufacture including instructions which when executed, cause a computer to implement the function/act specified in the flowchart and/or block diagram block or blocks. The computer program instructions may also be loaded onto a computer, other programmable instruction execution apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatuses or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. 
         [0050]    Referring to  FIG. 1 , system  100  includes server  102 . In a preferred embodiment, is a UNIX system operated on a modern server hardware platform including at least one processor, and a random access memory with at least one local storage drive organized to contain various data structures. 
         [0051]    The server is connected to display  104  and database  106 . The server includes several software modules. GPS management module  108  resides in memory and is responsible for collecting GPS position data from a number of GPS tags, to be later described. 
         [0052]    The server includes synchronization routine  110 , which resides in memory, and is responsible for synchronizing location information from the RTLS control system and the GPS tags, as will be further described later. 
         [0053]    The server includes overlay generator  112 , which resides in memory. The overlay generator is responsible for converting tabular location information into a graphics file, compatible with the BIM modeler to be displayed in real-time in association with the BIM construction model. 
         [0054]    The server includes BIM modeler  114 , which resides in memory. The BIM modeler is a graphics display routine which displays various graphics files or “overlays” in a construction model, such as a .CSV file. In a preferred embodiment, the BIM modeler uses Revit System, available from Autodesk, as previously described. 
         [0055]    System executable file  115  activates and coordinates the function of the various modules of the system and is responsible for execution of the various methods of system set up and installation. 
         [0056]    RTLS com  113  is a module responsible for communications and upload of data from the RTLS control system. 
         [0057]    In a preferred embodiment, the server is connected to network  116 , which is in turn connected to RTLS control system  118  and cellular repeater  120 . In one preferred embodiment, the network is the internet. In another preferred embodiment, network  116  can be an intranet such as an Ethernet connection which connects the repeater, the RTLS control system and the server. 
         [0058]    In a preferred embodiment, the RTLS control system includes central timing element  198  that synchronizes each sensor one to another. The RTLS control system, which also includes a central processor, is connected to the network. The RTLS system can provide simply proximity information based on the position of the RFID tag relative to the sensor position. In a preferred embodiment, the closest sensor is reported as the RFID tag location. The RTLS system also may be programmed to triangulate positions of the RFID tags, and thereby report a more accurate location of the RFID tag as a combination of signals from different sensors. The sensors, being synchronized, are capable of detecting pulses and measuring time difference of arrival (TDoA) of RFID tag. Processor  199  may also be programmed to utilize the TDoA data to compute velocity vectors and to compute quality of detected positions. 
         [0059]    A suitable RTLS system for the preferred embodiment is the Series 7000 RTLS platform from Ubisense, Ltd. which employs UWB RF tags capable of sustaining a continuous 160 Hz update rate, so that a RFID tag location can be provided every 6.25 ms from each sensor and cell area. The Ubisense system utilizes a 2.4 GHz ISM band wireless network to accomplish communications between the RFID tags and the system. Other RTLS systems that provide proximity notification will also suffice. 
         [0060]    The system further includes sensor node array  122 . Sensor node array  122  consists of a series of interconnected sensor cells, as will be further described. The system includes a set of RFID tags, such as RFID tags  124 ,  126  and  128 . In a preferred embodiment, the RFID tags are pulsed source tags available from Ubisense, Ltd. in conjunction with the series 7000 RTLS platform. The RFID tags generate a continuous stream of UWB RF pulses for ranging. The RFID tag devices in combination with a separate wireless network are capable of encoding information bits that are passed to the RTLS system. 
         [0061]    The system includes Cellular repeater  120 . Cellular repeater  120  is a compact  3 G indoor wireless access point which provides cellular service inside concrete and steel structures such as buildings. The cellular repeater is designed to assure continuous coverage regardless of proximity and connections to other macro networks. 
         [0062]    The system includes a set of GPS tags, such as GPS tags  130 ,  132  and  134 . GPS tags communicate through cellular repeater  120  to network  116  to transmit coordinate locations. In a preferred embodiment, each GPS tag is the Simvalley GT-280 GPS Tracker, available from Simvalley Mobile of Campbell, Calif. 
         [0063]    Referring to  FIG. 2A , in the preferred embodiment, a depiction of cell areas  200  is shown. The sensors are arranged in a set of sensor cells  290  made up of interconnected compound sensor nodes  291 . The sensor nodes are connected to RTLS control system  118 . 
         [0064]    While the sensor nodes may be configured in an infinite number of geometrical configurations, the preferred embodiment is to place the sensor nodes such as to form hexagonal shaped sensor cells. The hexagonal shape is advantageous because it capitalizes on the beam pattern of known antennas to maximize power usage and to eliminate both the presence of deadspots and increase the efficiency of cell-to-cell hand-off for positional and velocity determination near cell borders. Other shapes, such as square or perpendicular polygons are also possible. Further, three dimensional arrangements are possible for construction projects with multiple levels. The typical physical size of sensor cells are approximately 90 feet in diameter and the typical positional resolution of the Ubisense based RTLS is 15 cm in three dimensions. 
         [0065]    Referring to  FIG. 2B , each sensor node in the set of sensor nodes  291  contains a plurality of sensors capable of sensing information transmitted from pulsed signal sources and the directionality of pulsed signals generated from the pulsed signal sources. Each sensor node  291  contains an array of sensors  292 A,  292 B, and  292 C. In a preferred embodiment, these sensors are positioned at 120° angles to each other in each sensor node. In other embodiments, each sensor node can incorporate a different number of sensors, from 1 to 10, depending on the radiation pattern emitted. Sensors can be paired at different angles. 
         [0066]    RFID tag  295  emits UWB RF pulses which are detected by sensor node  291  among other sensor nodes. In the preferred embodiment, ultra wide band (UWB) radio frequency (RF) pulses are utilized for the RFID tag signals. Other embodiments may use different types of signals such as ultrasound or RF signals such as those used by cellular networks. The sensors are capable of detecting the angle of arrival (AoA) of UWB RF pulses generated from the UWB pulsed sources. Each sensor is capable of measuring the angle of arrival, AoA  296 , of the signal from the RFID tag. In other embodiments, the sensors can be set to run in “proximity mode,” indicating only if an RFID tag is present or not. 
         [0067]    The sensor array also includes dedicated sensor “portals,” such as portals  205  and  210 . The portals are generally positioned at fixed locations on the construction site, away from the sensor array, such as doors, gates and construction elevators. In a preferred embodiment, each portal includes a MOD3 reader cabinet which includes both a reader emit and mounted in a weather proof cabinet, available from Industrial Portals, a Jamison Door Company of Hagerstown, Md. 
         [0068]    Referring to  FIG. 3 , an exemplary deployment of the system at a construction site is described. Exemplary construction site  300  includes a perimeter  302 , usually fenced. The perimeter has entry/exit gates  304  and  306  at which portals  322  and  318  are located. The construction site includes an elevator  308  at which portal  320  is located. A building  310  is located within the perimeter. The building can include several floors, or levels. Each level of the building includes a set of site survey control points  312  and  314 . A “honey comb” RTLS deployment is shown at  316 . Sensors are located at the corner of each honeycomb cell. Each level, or floor, of building  310  includes a separate RTLS deployment. A series of four quadrilateral “zones” are shown as defined in the BIM model at  330 ,  331 ,  332 , and  333 . 
         [0069]    Each construction site is different and typically requires a different number of workers, a different building configuration and a different perimeter. Each system will have common elements, but the number and configuration of those elements typically changes for each construction project. 
         [0070]    Referring to  FIG. 4 , process  400  of deployment of the system is described. At step  402 , site survey points are calibrated to GPS coordinates, for this way, the BIM model is accurately calibrated to provide “real-world” coordinates. In a preferred embodiment, the GPS location of each site survey point is located with a hand-held GPS locator. At step  404 , the RTLS sensors are installed at the building facility and calibrated. Calibration of the RTLS systems requires locating each sensor in a defined three dimensional space and determining its exact location and orientation in space (its roll, pitch and yaw). 
         [0071]    At step  406 , “zones” are determined in the BIM model. “Zones” are predefined areas within the building construction project. The zones are independent of the RTLS sensor locations. At step  408 , the zones are imported into the RTLS system. During import, an offset is acquired from the calibrated site survey points. The offset orients relative three-dimensional information related to the site survey points into absolute GPS compatible positions. 
         [0072]    At step  410 , the required GPS transponders are installed at the construction site. At step  412 , the RFID tags are configured. At step  414 , the GPS tags are configured. 
         [0073]    The BIM zone object is a complex object having various display parameters. In a preferred embodiment, the parameters include relative GPS coordinates that define a three-dimensional area of space at the construction site. A color hue parameter is also provided. This parameter includes a table of colors to indicate different information. In a preferred embodiment, the information includes number of workers, area of expertise and a percentage job completion. Other parameters may be specified in the table. In the preferred embodiment, a color density, opacity or intensity may also be employed to indicate numerical values. 
         [0074]    Referring to  FIG. 5 , process  500  of RFID tag and GPS tag configuration will be discussed. At step  502 , the server registers a unique personnel id for each person to be tracked with the system. At step  504 , each person is assigned a unique RFID tag. At step  506 , each person is assigned a specific GPS cell number. Each person may be associated with a single RFID tag, a single GPS cell number, or both. This is important on construction sites where one type of tag is not functional throughout the entire site due to “dead spots” or obstructions, moving or fixed. 
         [0075]    At step  508 , the server receives demographic data about the person, such as name, field of expertise and authorization level for various zones. 
         [0076]    At step  510 , the server receives construction job data which identifies the job location, BIM map information, and other information, such as insurance status, pay scale status, contract status, and work zone completion benchmarks. 
         [0077]    Referring to  FIG. 6 , use of system  600  will be described. At step  602 , the RTLS control system is activated and begins collected data from the RTLS tags and storing it in an RTLS data table. The data table is continuously updated with new RTLS tag locations. At step  604 , the system executable file pings cellular repeater  120  to make sure it is active. At step  606 , the system executable file uploads the RTLS data table from the RTLS control system for a predetermined time period t 1 . At step  608 , the system executable file communicates with the GPS management module to upload the GPS data table for predetermined time period t 1 . 
         [0078]    At step  610 , the server synchronizes the RTLS data table and the GPS data table into a master data table, to be further described. 
         [0079]    At step  611 , the processor updates the master data table with location data for each time period t. At step  612 , the system executable file constantly monitors the BIM model module for requests for information. If not received, the process returns to step  606 . If a BIM model request is received, the process proceeds to step  613 . 
         [0080]    At step  613 , the BIM request is analyzed for requested zones. At step  614 , the process queries the master data table to obtain which tags are located in the requested zone. At step  616 , a .CSV file is prepared. Preparation of the .CSV file includes the novel comparison of various numerical values to a color hue density table to arrive at “translucency” parameters which provide data to color each particular requested zone with a particular translucent color, to be displayed by the BIM modeler, as will be further described. 
         [0081]    At step  618 , database  106  is queried to correlate personnel identification data with the location data from the master table. In a preferred embodiment, the personnel identification data is tabulated for display by the BIM modeler. 
         [0082]    At step  620 , the .CSV file and correlated personnel identification data are queued for upload to the BIM modeler. At step  622 , the .CSV and correlated personnel identification data file is uploaded to the BIM display system. At step  624 , the BIM modeler displays the graphics file including the graphics overlay, to be further described. 
         [0083]    Referring to  FIG. 7 , process  700  carried out by the RTLS control system  118  will be further described. At step  702 , the RTLS control system receives a start command from the server. At step  704 , the RTLS control system begins to monitor the sensor nodes to receive signals from each of the RTLS tags. In a preferred embodiment, the signals include proximity signals, AoA signals and t disl  signals. At step  706 , the RTLS signals are received. At step  708 , each RFID tag ID is logged along with location according to a predetermined number of zones. At step  710 , the location information is correlated with a time stamp or a predetermined time interval t 1 . 
         [0084]    At step  712 , the RTLS control system prepares the data table for upload, which includes the RFID tag ID, location and time stamp. An event notification can be sent to the server of movement of one or more of the RTLS tags. 
         [0085]    At step  714 , the RTLS control system advances to the next time interval t and returns to step  704 . 
         [0086]    Referring to  FIG. 8 , functions  800  of GPS management module  108  will be described. At step  802 , the GPS management module receives GPS transponder information from each GPS tag via cellular repeater  120 . In an alternate preferred embodiment, each GPS tag communicates with a local cellular tower which is provided to GPS management module  108  through network  116 . At step  804 , the GPS management module receives GPS tag location from the cellular tower. At step  806 , the GPS management module logs the longitude and latitude received from the GPS tag. At step  808 , the time stamp or predetermined time period t 1  is associated with the tag location and GPS tag ID. In the preferred embodiment, the GPS tag ID is the cellular phone number associated with the GPS tag. 
         [0087]    At step  810 , the GPS management module prepares a data table for upload the system executable file  115 . At step  812 , the GPS management module advances to the next time interval t and returns to step  802 . 
         [0088]    Referring to  FIG. 9 , the synchronization method  900  of the master table accomplished by synchronization module  110  will be further described. 
         [0089]    At step  902 , the synch module uploads the RFID location table. At step  904 , the module uploads the GPS location table. At step  906 , the synchronization module creates a master table based on tag ID. As shown below in Table 1, for each personnel ID there may be an associating RFID tag number and/or GPS tag number. If both an RFID and GPS tag number are included, the synchronization module will upload two separate tables whose data may or may not agree as to tag location, for each time interval. In order to eliminate conflicting data, synchronization module compares and examines the GPS location data against the tag location data. 
         [0090]    A table showing an example of the data as read and the synchronization determined by the method  1000  is below: 
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Time 
                 GPS Location 
                 Tag Location 
                 Synch Location 
               
               
                   
               
             
             
               
                 t 1   
                 1 
                 1 
                 1 
               
               
                 t 2   
                 1 
                 1 
                 1 
               
               
                 t 3   
                 2 
                 1 
                 2 
               
               
                 t 4   
                 2 
                 2 
                 2 
               
               
                 t 5   
                 2 
                 3 
                 3 
               
               
                 t 6   
                 3 
                 3 
                 3 
               
               
                   
               
             
          
         
       
     
         [0091]    Referring then to  FIG. 10 , method  1000  of eliminating conflicting data and synchronization mismatches will be described. 
         [0092]    At step  1010 , the processor advances to a time period. At step  1015 , the processor reads the GPS tag location at time period t 1 . At step  1020 , the processor reads the tag location at time period t 1 . At step  1025 , the processor compares the GPS tag location at time period t 1  to the tag location at time period t 1 . If the two are “close,” then the processor moves to step  1030  where it reports the GPS location as the synch location. “Close” is a Boolean function that returns “true” if the two positions are within a predetermined distance. The processor then returns to step  1010 . If the GPS tag location at time period t 1  is not equal to time period t 1 , then the processor moves to step  1035 . At step  1035 , the processor reads the GPS location at the next increment of time t 2 . At step  1040 , the processor reads the tag location at the next increment of time t 2 . At step  1045 , the processor compares the GPS tag location at time t 1  to the GPS tag location at t 1 . If the two are not equal, the processor then proceeds to step  1050 . At step  1050 , the processor report the GPS tag location as the synch location. If the two are not equal, the processor proceeds to step  1055 . At step  1055 , the processor compares the tag location and time t 1  to the tag location and time t 2 . If the two are not equal, the processor then proceeds to step  1060 . At step  1060 , the processor reports the tag location and time t 2  as the synch location. The processor then returns to the step  1010 . If the tag location and time t 1  are equal to the tag location and time t 2 , then the processor reports the GPS location at time t 2  as the synch location and returns to step  1010 . 
         [0093]    The method applied by the synchronization modules results in the fastest and most reliable zone identification as between the two competing GPS and RFID systems. 
         [0094]    Referring to  FIG. 11 , a flow chart  1100  of a preferred embodiment of deriving a color transparency value will be described. At step  1102 , the processors sort the synchronized location data by geographic zone, allocating the location of each of the personnel for the predetermined time period into a specific zone, at a predetermined time period. 
         [0095]    At step  1104 , the processor counts total number of personnel for each zone. At step  1106 , a color transparency value is assigned according to a range of total number of personnel in each zone. In a preferred embodiment, lesser numbers of total personnel are assigned a higher transparency value. Likewise, higher numbers of total personnel in each zone are assigned a lower transparency value. Colors with high transparency values appear nearly transparent for each zone. Colors with low transparency values appear more opaque in each zone. Varying transparency provides a novel visual abstraction for each zone indicating “at a glance” the general number of personnel in each zone for any given time period. 
         [0096]    In other preferred embodiments, the visual abstraction can include a colored geometric representation of each person, located in a zone for the predetermined time period. 
         [0097]    At step  1108 , the processor assigns a geometric shape to each person, such as a sphere or a cube. The shape is scaled so as to be large enough to be recognized in BIM model. 
         [0098]    At step  1110 , a color is assigned to each person depending on chosen demographic criteria, such as profession. At step  1112 , the shape is located at the synchronized position for each person. 
         [0099]    At step  1114 , the color transparency values are imported into the .CSV file, to be used by the BIM modeler in each zone, for each time period. 
         [0100]    Referring to  FIG. 12 , a display generated by the BIM modeler will be described. The BIM modeler displays a wire frame model of building  310 , in three-dimensions. The overlay shades zones  1202  and  1203 , according to the transparency value, if personnel are present in those zones during the predetermined time period. In a preferred embodiment, the zones are color coordinated for easy visual identification. Geometric representations of personnel for the predetermined time period are shown at  1204 . 
         [0101]    A master data table  1205  is displayed on the screen, which indicates personnel ID  1206 , personnel location  1208 , time period  1210 , whether or not the personnel is authorized to be in the zone  1212 , and the expertise of the personnel  1214 . In this example, a plumber is shown as a “P,” an electrician is shown “E”. The data table may be sorted according to any column for ease of data interpretation. Legend data table  1216  is displayed on the screen which, in this example, shows a range of number of workers in the sensor zones. The master data file and/or the shaded zones form a visual abstraction of data relevant and timely to the BIM model. Of course, other information can be displayed in the legend data table. 
         [0102]    In an arcuate embodiment, the display generated by the BIM modeler includes a display and a series of overlays made in time order for a progressive series of time periods. The progressive display of overlays creates a “movie-like” presentation of the visual abstractions of the personnel data. For example, color transparency may vary from light to dark over time. Similarly, geometric representations of personnel will change in location. 
         [0103]    Although various embodiments have been described in detail, those skilled in the art will understand that changes, substitutions and alterations can be made without departing from the spirit and scope of what has been described. Accordingly, all such changes, substitutions and alterations are intended to be included as defined in the following claims.