Patent Abstract:
An enhanced positioning and navigational system for use within a building or otherwise separated by a line-of-sight barrier from an orbiting global navigation satellite system such as Navstar GPS. An antenna placed at a known location within line of sight of orbiting global navigation satellites receives global position and navigation signals and relays the signals through the line-of-light barrier to an identifier which identifies the signals and couples the signals for individual broadcast from each of an array of broadcast antennae located at known fixed locations within the building (behind the line-of-sight barrier). A receiver located within the building receives the signals broadcast from the antenna array and through use of a processor interprets the signals to provide position and navigation information to the user of the receiver. 
     In an alternate embodiment, a signal generator generates navigation and positions information signals of a multiplicity of broadcast beacons. The information signals are separated into parcels corresponding to individual beacons and then are separately broadcast from each of all array of antennae located at fixed, known locations within a building. A radio position and navigation receiver equipped with a processor provided with appropriate software receives the signals and provides radio position and navigation receiver information to the user of the GPS receiver. In another alternative embodiment, plural pseudolites are placed at accurately established fixed locations within a building. A controller causes the pseudolites to sequentially broadcast global navigational satellite system signals. A GPS receiver equipped with a processor provided with appropriate software receives the signals and provides navigation and positioning information to the user of the GPS receiver. Alternative methods for sequencing the signals broadcast by the pseudolites are also disclosed.

Full Description:
CROSS REFERENCE TO CO-PENDING PROVISIONAL APPLICATION 
     This application claims the benefit under 35 U.S.C. §119(e) and 37 C.F.R. §1.78 of copending provisional patent application entitled “Enhanced Global Position System”, Ser. No. 60/060,515 filed Sep. 30, 1997, from which this application claims priority. The disclosure of provisional patent application Ser. No. 60/060,515 is hereby incorporated in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to facilitating the use of radio signals for positioning and navigation where a barrier (solid or non-solid) precludes direct usage of public line-of-sight radio positioning/navigation beacons. Although several embodiments of the present invention are described herein, the focus is on the use of repeated geometrically non-linear Global Navigation Satellite System signals within a line-of-sight barrier. 
     DISCUSSION OF THE PRIOR ART 
     A common need of our society is to accurately track and record positions of aircraft, land vehicles, geographical landmarks, materials, buildings, animals, people, and other items. One system currently used to accomplish this goal in direct line-of-sight is use of public radio positioning/navigation signals and associated equipment. Radio positioning/navigation can be broadly defined as the use of radio waves to transmit information, which in turn can then be received and utilized to determine position and to navigate. Some radio positioning/navigation systems currently in use are Loran, Omega, LMN, DGPS, and Global Navigation Satellite Systems (GNSS) such as NAVSTAR, GLONASS (the Russian variant), and European systems (GNSS1, GNSS2, NAVSTAT and GRANAS). The radio navigation systems quickly becoming the standard worldwide are Global Navigation Satellite Systems (GNSS) including, in the United States, the NAVSTAR Global Positioning System. 
     The NAVSTAR GPS signal transmission system presently consists of twenty-four orbiting satellites, spaced in six separate circular orbits, with each accommodating four satellites. Of these, twenty-one are normally operational and three serve as spares. Each NAVSTAR GPS satellite reappears above the same ground reference approximately every twenty-three hours and fifty-six minutes. The spacing of satellites is designed to maximize probability that earth users will always have at least four satellites in good geometrical view for navigational use. 
     The basic method of position determination via radio positioning and navigation signals derives from the concept of triangulation. The term triangulation used herein refers to the general process of determining distance, a.k.a. range, from the present position to multiple known beacons, and mathematically solving for the point in space which satisfies these conditions. As applied to GNSS, the procedure requires calculation of signal travel time, which, when multiplied by the speed of light, renders distance. 
     In support of this computation, the normal radio signals transmitted by each broadcasting NAVSTAR GPS satellite are currently configured as follows: a 1575.42 MHZ “L1” carrier modulated by the 10.23 MHZ P-code (Precision), the 1.023 MHZ C/A-code (Coarse/Acquisition), and the 50 Hz navigation code; and a 1227.60 MHZ “L2” carrier modulated by the 10.23 MHZ P-code and the 50 Hz navigation code. Because the system was principally designed for military use, the P-code is classified, and the L2 carrier is not officially supported for civilian use. 
     Each satellite repeats its pre-defined, unique 1023-bit C/A-code every millisecond. This code identifies the sending satellite and, since the pattern is exactly known, the code-point at which the signal arrives serves as a marker for estimating arrival time (complex algorithms are applied for refining measurement accuracy). 
     The NAVSTAR GPS navigation message transmits various data including precise time information every six seconds, orbital parameters (ephemeris data), correction statistics, and satellite status. The basic data is divided among five frames over thirty seconds, with the total message spread over 12.5 minutes. The layout of data is designed such that once a receiver has accumulated the necessary background data, it acquires an update of precise time every six seconds from which navigation calculations can be made. The position of the satellite at time of transmission is computed based on its known orbital path along with current ephemeris data. 
     Initial range calculations are called “pseudoranges” since receiver clocks are not precisely synchronized to NAVSTAR GPS time, and propagation through the atmosphere introduces delays into the navigation signal propagation times. These result, respectively, in clock bias error and atmospheric bias error. Clock bias errors may be as large as several milliseconds. 
     Conventionally, a minimum of four GNSS satellites are sampled to determine a terrestrial position estimate (e.g. Cartesian X,Y,Z coordinates; or longitude, latitude, and altitude in any of various systems including WGS84, NAD83, NAD27, Indian, etc.). Three of the satellites are used for basic triangulation, and a fourth is used to solve for clock bias between the satellite system and the receiver. Ephemeris correction statistics from the navigation message assist in amelioration of atmospheric bias. 
     Other errors which affect GNSS position computations include receiver noise, signal reflections, shading, satellite path shifting, and in the case of NAVSTAR GPS, purposely induced accuracy degradation called selective availability (S/A). 
     A process known as differential positioning compensates for many of the errors which are common in radio positioning/navigation systems. An antenna at a known location receives line-of-sight (LOS) GNSS signals and broadcasts a signal with current correction adjustments for each satellite which can be received by any differential receiver within its signal range. 
     Location accuracy via GNSS is continually evolving. Standard GNSS receivers can typically produce position estimates within ±60-100 meter accuracy. Sub-meter accuracy of location can be achieved using differential positioning, known as DGPS. Some other techniques for improving accuracy are “Carrier-phase GPS”, “Augmented GPS”, and GPS Interferometry. 
     GNSS relies on no visual, magnetic, or other point of reference and this is particularly important in applications such as aviation and naval navigation that traverse polar regions where conventional magnetic navigational means are rendered less effective by local magnetic conditions. Magnetic deviations and anomalies common in standard radio positioning/navigation systems do not hinder GNSS. In addition, GNSS equipment is typically fabricated of standard, solid state electronic hardware, resulting in low cost, low maintenance systems, having few or no moving parts, and requiring no optics. GNSS does not have the calibration, alignment, and maintenance requirements of conventional inertial measuring units. Also, GNSS is available 24 hours per day on a worldwide basis. 
     During the development of the NAVSTAR GPS program the United States Government made decisions to extend its use to both domestic and international communities. Its applications range from navigation over the land, in the air, and on the seas, to precision surveys, the tracking of trains and trucks, and even locating undetonated mines left behind in the Gulf War. It is important to note that GNSS solutions are only accomplished when the GNSS receiver is in direct line-of-sight (LOS) with the orbiting GNSS satellites. In other words, if the GNSS receiver&#39;s antenna is used in heavily forested areas, in steep and narrow canyons, within a structure, or adjacent to the outer walls of buildings, the GNSS receiver will be unable to obtain a good repeatable reading, or in many cases, any reading at all. 
     What is needed is a system that relays GNSS signals beyond a line-of-sight barrier (LSB) and mathematically corrects satellite pseudorange calculations to account for geometrically nonlinear satellite signal paths. The result of such a system is accurate, consistent readings for multitudes of applications which need, or require, positioning and navigation information when out of the line of sight of a GNSS satellite system. 
     SUMMARY OF INVENTION 
     The present invention provides a system for use of GPS receivers separated by a barrier from being in the line of sight of orbiting GNSS satellites, hereinafter referred to as “within a line-of-sight barrier”. An exterior receiving antenna is positioned outside the line-of-sight barrier at a known location to receive ephemeris and pseudorange signals from a GNSS system of orbiting satellites. Optional correction signals from a DGPS antenna may also be used. The signals received by the exterior antenna are passed through the line-of-sight barrier, such as a building roof, to a signal identifier which identifies and may amplify the signals and then transmits the signals to a plurality of broadcast antennae placed at known locations within the line-of-sight barrier, preferably at differing spacings from the ceilings of the building in which the invention is being employed. Each of the broadcast antennae broadcasts the identified signals either sequentially or at different frequencies. A standard GPS receiver capable of receiving GPS and optional DGPS signals may be co-positioned with the exterior antenna. The retransmitted signals are received by a GPS receiver coupled to a host computer. Allowance for the displacement of the signal path from a linear path to a three-dimensional multilegged path is made by the host computer in order that the data received by the GPS receiver operating within the line-of-sight barrier is used to calculate the position into that which would be received by the receiver if no roof or other line-of-sight barrier interrupted the line-of-sight path of the GPS signals transmitted by the orbiting GNSS satellites. 
     In an alternate embodiment of the invention, a plurality of broadcast antennae located within a building emit signals imitative of a GNSS system of satellites. Line-of-sight data received by GPS receivers located in the building from any four of the broadcast antennae permit the GPS receivers to display or transmit location, altitude and navigational data while in line-of-sight range of any four interior broadcast antennae. 
     Accordingly, it is the primary objective of the present invention to extend the current use of the existing line-of-sight GNSS system to locations within a line-of-sight barrier. 
     The present invention specifically comprises a receiver with antenna positioned in direct line-of-sight of a public radio positioning/navigation transmission system (e.g. GNSS, NAVSTAR GPS, GLONASS). The acquired signals are passed through the line-of-sight barrier, identified, amplified (as needed), and relayed to a strategically arrayed constellation of broadcast antennae. The radio positioning/navigation receiver located within a line-of-sight barrier receives the repeated, geometrically non-linear signals and utilizes appropriate software to calculate its coordinates within a line-of-sight barrier, to be used for positioning and navigational purposes. 
     The present invention utilizes the following: GPS receiving antenna, signal identifier/amplifier/repeater (IAR), GPS broadcast only antennas, GPS receivers, supplemental data links and a host computer/data processor, GPS signal processing software, and three-dimensional, parametric, database-driven, geometric solution software (vector geometry). Optionally, a DGPS receiving antenna and DGPS receivers may be used for enhanced accuracy. 
     The primary method of accomplishing the objective utilizes geometrically non-linear, non line-of-sight, repeated GPS signals to calculate accurate location data for applications within a line-of-sight barrier (LSB). 
     The primary invention is an accurate extension of GPS from a line-of-sight only (LOS) to a system that can be used within a line-of-sight barrier (LSB) which derives data from the GPS satellite signals and the optional DGPS correction signals, which are passed through a line-of-sight barrier (LSB), and used in conjunction with a supplemental data link and a host computer/data processor. 
     The system derives accurate position information from line-of-sight data signals directly from the GPS satellites, and optional DGPS antennae at a fixed receiver location outside the line-of-sight barrier (LSB). The GPS receiver operating in line-of-sight view of the GPS satellites then transmits positional data to a host computer database. Simultaneously, the signals are passed through the line-of-sight barrier (LSB) to a signal identifier/amplifier/repeater (IAR). After the signals are identified, they are sent to a set of broadcast antennas located at known fixed locations, contained within the line-of-sight barrier (LSB). The receiver within the line of sight barrier (LSB) then directly receives the repeated, passed through GPS signals that can be processed and used within the line-of-sight barrier (LSB) for location and navigation purposes that are ultimately only an extension of an existing GPS. 
     Alternatively, a secondary general configuration is a more self-contained system that will create line-of-sight positioning data within a line-of-sight such as a building. This secondary solution to the present invention will employ its own master clock, a host computer/data processor, GPS broadcast-only antennas, signal amplifiers, supplemental data links, GPS signal processing software, and specially programmed three-dimensional, parametric, database-driven, geometric solution software, and GPS receivers. 
     It is an object of the invention to utilize GNSS satellite radio positioning/navigation signals which have been acquired outside a line-of-sight barrier. 
     It is a further object of the invention to pass GNSS satellite signals through a line-of-sight barrier. 
     It is still a further object of the invention to identify, distribute by means of switching in a controlled manner, amplify, and re-radiate the GNSS satellite signals within a line-of-sight barrier. 
     It is still a further object of the invention to use a GNSS receiver made from commercially available hardware, to receive geometrically non-linear, GNSS satellite signals within a line-of-sight barrier. 
     It is still a further object of the invention to integrate commercially available processor hardware and software to collect standard GNSS signals and associated data to calculate positioning and navigation solutions within a line-of-sight barrier. 
     It is still a further object of the invention to utilize GPS information for recording the locations of people, resources, products, inventory, work-in-process all outside the line of sight of the global navigation satellite system satellites. 
     These and other objects will be better understood from review of the detailed description which follows and in which the following definitions are applicable. 
     DEFINITIONS 
     Global Navigation Satellite System (GNSS)—A generic term for specific systems such as the Russian GLONASS and the United States NAVSTAR GPS, utilizing equipment which receives signals from a relevant constellation of navigational satellites in earth orbit. 
     NAVSTAR Global Positioning System (NAVSTAR GPS)—The United States Government&#39;s satellite navigation system which broadcasts time and ranging data globally. Designed to provide a highly accurate, reliable, continuous  24 -hour, worldwide coverage for position reporting and navigation. 
     Differential Global Positioning System (DGPS) or Differential Global Navigation Satellite System (DGNSS)—A positioning system which also includes an antenna that is precisely surveyed to a known location. The antenna receives GPS signals and broadcasts current correction data for each satellite which can be received by a DGPS antenna. Location accuracy within one meter can be achieved. 
     Time of Arrival (TOA)—A broadcast beacon sends out a signal starting at some precise instant in time and a receiver which acquires the signal at some later point in time. This time difference is the TOA. 
     Time Delay (TD)—The total time a signal is delayed, versus straight line through a vacuum, as it travels from one fixed location to another. 
     Line-of-Sight—(LOS) Unobstructed linear signal path between radio positioning/navigation transmitters and receiving antennae. 
     Line-of-Sight Barrier—(LSB) Any barrier, solid or non-solid, that restricts direct linear receipt of any radio positioning/navigation signal. 
     Radio Frequency (RF)—Radio transmission of data. 
     Selective Availability (S/A)—The Military dithers the satellite clock and manipulates ephemeris data to deny navigational precision to potential adversaries. These errors, in turn, lead to a reduction in precision of position estimates. 
     Simulated Global Navigation Satellite System (SGNSS)—GNSS satellite data which is generated and broadcast within a line-of-sight barrier. 
     Radio Positioning/Navigation Signal (RPNS)—Any radio positioning/navigation signal, such as LORAN, OMEGA, etc. broadcast within a line-of-sight barrier. 
     Receiver—Hardware that is capable of receiving radio positioning/navigation signals 
     Processor 
     a. Integrated Processing System (IPS)—A radio positioning/navigation receiver with an integrated solution processor. 
     b. External Processing System (EPS)—A radio positioning/navigation receiver that is linked via RF or hardwire to an external computer data processor. 
     Geographical Information System (GIS)—Any information system that is designed to work with data referenced by spatial or geographic coordinates. A GIS is both a database system with specific capabilities for spatially-referenced data, as well as a set of operations for mapping and analyzing the data. 
     Wide Area Augmentation System (WAAS)—A system where a network of ground reference stations monitors GNSS satellite signals and passes the information to a Master Station. The Master Station uplinks correction data to Geostationary satellites (not the GNSS navigation satellites) which in turn downlink the correction data to a user&#39;s GNSS receiver. This system is designed to improve integrity, accuracy, availability, and continuity of service, with a view to accuracy being compatible with aircraft approach and landing aids, and other uses where such accuracy is required. 
     Triangulation—Any mathematical procedure to calculate position based on the intersection of ranges from known points (includes all variations such as trilateration and resection, etc., whether or not angles, per se, are used). 
    
    
     DESCRIPTION OF THE DRAWING FIGURES 
     FIG. 1 is a schematic representation of the preferred embodiment of the invention wherein location and time data from GNSS satellites is transmitted through a line-of-sight barrier, identified, amplified and rebroadcast from an array of antennae to any receiving unit within the line-of-sight barrier. 
     FIG. 2 is a schematic representation of an alternative embodiment of the invention which is deployed entirely within a line-of-sight barrier. 
     FIG. 3 is a schematic representation of another alternate embodiment of the invention similar to the alternate embodiment of FIG.  2 . 
     FIG. 4 is a schematic representation of the interrelated components within the processor unit employed within the system invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is now described with reference to the figures wherein like reference numbers denote like elements. 
     The present invention is a system which can fulfill the position/navigation accuracy of locating a radio positioning/navigation receiver operating within a line-of-sight barrier  100  using passed through, geometrically non-linear radio positioning/navigation signals. In the preferred embodiment of the present invention, this is accomplished by utilizing standard, and/or modified, radio positioning/navigation hardware and integrating commercially available software into a signal and data processor without the need for additional data or communication. 
     In describing the various embodiments of the present invention references will be made to a preferred embodiment and illustrative advantages of the invention. Several alternative embodiments of the present invention will also be illustrated in the following discussion. However, those skilled in the art and familiar with the instant disclosure of the present invention will recognize additions, deletions, modifications, substitutions, and other changes which will fall within the purview of the subject inventions and claims. 
     FIG. 1 illustrates the general configuration of the preferred embodiment of the present invention of a radio positioning/navigation system which is operating within a solid or non-solid line-of-sight barrier  100 . Examples of a solid line-of-sight barrier  100  include the roof of a structure, a heavy tree canopy, steep and narrow canyon walls, the walls of tall buildings, or within any enclosure. Examples of non-solid line-of-sight barriers  100  would include, but are not limited to, atmospheric anomalies, magnetic fields, etc. 
     The basic necessary elements of this system used to determine the positioning and navigational coordinates of a radio positioning/navigation receiver operating within a line-of-sight barrier  100  include: a constellation of broadcast antennae  130 ,  131 ,  132 ,  133  accurately surveyed to fixed, known locations relative to the user&#39;s choice of system coordinates, and a mobile receiver/processor  150  operating within the line-of-sight barrier  100  within line of sight of the broadcast antennae  130 ,  131 ,  132 ,  133 . The broadcast antennae  130 ,  131 ,  132 ,  133  are arranged in a geometrical pattern that is efficient for accurate triangulation with either a two- or three-dimensional radio positioning/navigation system, as applicable. Specifically, it should be noted that in a two-dimensional system the operating centers of the antennae are not all located co-linear, and in a three-dimensional system the operating centers of the antennae are not all located co-linear or co-planar. The transmission paths  140 ,  141 ,  142 ,  143  are direct line-of-sight distances from the fixed, known location, broadcast antennae  130 ,  131 ,  132 ,  133  to any mobile receiver/processor  150  which is operating within the line-of-sight barrier  100 . A fixed receiver/processor  160  with appropriate software uses data received from GNSS antenna  200 , to collect external pseudorange data, and transmits via transmission path  113  to processor  420 . The mobile receiver/processor  150  with appropriate software, uses the radio positioning/navigation signals received from the broadcast antennae  130 ,  131 ,  132 ,  133  to collect total time of arrival of the signal from the satellites  101 ,  102 ,  103 ,  104 . This data is transmitted via transmission path  113  to processor  420 . Specifically, in a three-dimensional system the operating center of the antennae cannot all be located co-planar. The transmission paths  140 ,  141 ,  142 ,  143  are direct line-of-sight distances from the broadcast antennae  130 ,  131 ,  132 ,  133  to the mobile receiver/processor  150  which is operating within line-of-sight barrier  100 . The processor  420  with appropriate software, uses the data collected from mobile receiver/processor  150  and fixed receiver/processor  160  to determine the present coordinates of mobile receiver/processor  150  by appropriate two- or three-dimensional geometric triangulation. 
     The preferred embodiment of the present invention illustrated in FIG. 1 focuses on the use of repeated, geometrically non-linear extension of GNSS signals within a line-of-sight barrier  100 . Twelve or more GNSS satellites may be in line of sight of the GNSS antenna  200 . At any one time only four satellites are needed for three-dimensional position determination, and are thus shown for clarity (more or fewer may be used in applications as desirable). These satellites are labeled as  101 ,  102 ,  103 ,  104 . The fixed receiver/processor  160  may be located inside or outside the line-of-sight barrier  100 . The GNSS signals are passed through the line-of-sight barrier  100 , split by signal splitter  109 , and transmitted via transmission paths  110  and  111  to the Identifier/Amplifier/Repeater  115  and receiver/processor  160  respectively. These transmission paths  110  and  111  may be either hard wired, or wireless. Transmission path  110  will cause individual time delays of the satellite signals which are being repeated. These delays in time must be factored into the calculation of the positioning and navigational coordinates for the mobile receiver/processor  150  operating within a line-of-sight barrier  100 . 
     The Identifier/Amplifier/Repeater  115  identifies the individual GNSS satellites  101 ,  102 ,  103 ,  104  by any of the following methods either singularly or in combination: splitting, tuning, heterodyning and deheterodyning (frequency shifting), tagging within the GNSS navigation signal. In one variation, the Identifier/Amplifier/Repeater  115  may separate the GNSS signals into identified separate signals corresponding to the individual signal sets received from each of satellites  101 ,  102 ,  103 ,  104 . The Identifier/Amplifier/Repeater  115  amplifies, and selects a channel to transmit the passed through satellite data via transmission paths  120 ,  121 ,  122 ,  123  to broadcast antennae  130 ,  131 ,  132 ,  133  respectively. 
     Re-radiating GNSS signals simultaneously from multiple indoor broadcast antennae is subject to a “near-far” problem. This problem arises because of the large variation of the user-to-broadcast antennae range. The average power being received from the GNSS space vehicles remains approximately constant due to the large distance of the space vehicles from the GNSS receiver(s). On the other hand, the broadcast antenna power from broadcast antennae  130 ,  131 ,  132 ,  133  varies a great deal, inversely proportional to the square of the GNSS receiver&#39;s distance from the broadcast antennae, and can overwhelm incoming GNSS satellite vehicle signals. A unique aspect of all embodiments of this invention is the sequencing of GNSS satellite vehicle signals in a controlled pattern to the broadcast antennae  130 ,  131 ,  132 ,  133  located with the line-of-sight barrier  100 . In this way the “near-far” problem is eliminated. Another way to eliminate this problem is heterodyning and deheterodyning the signal to different frequencies for each of the broadcast antennae  130 ,  131 ,  132 ,  133 . The mobile receiver/processor  150  is designed to handle GNSS satellite vehicle data coming from the sequenced broadcast through the indoor array of broadcast antennae  130 ,  131 ,  132 ,  133 . 
     These broadcast antennae  130 ,  131 ,  132 ,  133  are selectively located at fixed, known locations relative to the user&#39;s choice of system coordinates. The transmission paths  120 ,  121 ,  122 ,  123  cause individual time delays of the satellite signals which are being passed through the Identifier/Amplifier/Repeater  115  and repeated within the line-of-sight barrier  100 . Passage of signals through the Identifier/Amplifier/Repeater  115  causes an individual time delay that must also be factored into the calculation to determine the positioning and navigational coordinates of the mobile receiver/processor  150  operating within the line-of-sight barrier  100 . The transmission paths  140 ,  141 ,  142 ,  143  are direct line-of-sight distances from the broadcast antennae  130 ,  131 ,  132 ,  133  to the mobile receiver/processor  150  which is operating within the line-of-sight barrier  100 . 
     In order to calculate the position of a mobile receiver/processor  150  operating within a line-of-sight barrier  100 , normal vector geometry techniques are utilized. The position/navigation solution of the mobile receiver/processor  150  is relative to the location of the broadcast antennae  130 ,  131 ,  132 ,  133  located within a line-of-sight barrier  100 . The solution calculates the standard Cartesian X,Y,Z coordinates, or latitude/longitude/altitude, or customized local coordinate systems. For those versions of the invention which involve relaying public navigation/position signals and retransmitting them within a line-of-sight barrier  100  (as opposed to signal generation within the line-of-sight barrier  100 ), a unique innovation is incorporated into the triangulation algorithm in order to account for the geometrically non-linear signal path. The core of the solution resides in use of the real space, three-dimensional, parametric, database driven, graphical solution software. 
     For one skilled in the art, the following describes the essential characteristics of a type of three-dimensional, parametric, database driven, graphical solution software which may be employed in the invention: 
     Works in real size (one-to-one scale); 
     Works three-dimensionally using vector geometry (Cartesian X,Y,Z coordinates); 
     Works with GIS mapping overlays and can apply the elements of time; 
     Works in real time; 
     Works with database variables which can be applied to the three-dimensional, parametric, database driven, graphical solution models; 
     Works with parameters as algebraic input; 
     Works by representing the specific positioning and navigational results graphically. 
     FIG. 4 illustrates the processor  420  which receives the geometrically non-linear, repeated GNSS data via transmission path  410  within a line-of-sight barrier. Processor  420  receives external pseudorange data via transmission path  113 . Processor  420  uses data acquisition software (DAQ)  510 , relational database management software  515 , satellite position prediction software  520 , and three-dimensional, parametric, database-driven, graphical software  530  which will calculate a post-processed solution of the repeated, geometrically non-linear GNSS or radio positioning/navigation signals which have been passed through line-of-sight barrier. Processor  420  may be a personal computer capable of operating the “Windows 95” operating system of Microsoft Corp. and may be of the type equipped with a Pentium processor operating at no less than 100 MHz and having internal memory of at least 16 megabytes. Processor  420  may be internal or external. An external processor may be shared with multiple mobile receiver/processors  150 . 
     The following commercially available software may be employed by processor  420  for the functions described above: 
     Data Acquisition software (DAQ)  510 : 
     Magellan GPS Post Processing Software published by Magellan System; 
     Relational Database Management System software (RDMS)  515 : 
     Oracle published by Oracle Corp.; 
     Paradox published by Corel Corp.; 
     Fox Pro published by Microsoft Corp.; 
     Dbase supported by Inprise Corp.; 
     Access published by Microsoft Corp.; 
     GNSS Satellite Position Prediction Software  520  (Optional): 
     SatNAV Toolbox published by GPSoft Inc.; 
     Jupiter 4.0 published by Position Inc.; 
     Aslab published by Accord Software System. 
     Three Dimensional, Parametric, Database Driven, Graphical software  530 : 
     AutoCAD Mechanical Desktop published by Autodesk, Inc.; 
     Solidworks published by Solidworks Inc.; 
     Matlab published by Mathworks Inc. 
     The above-referenced software may be integrated utilizing the following “Windows” Programming Development Tools: 
     Delphi published by Inprise Corp. 
     Visual Basic published by Microsoft Corp. 
     C++ Builder published by Inprise Corp. 
     The above referenced software is compatible with a variety of network operating systems including Windows 95, Windows 98, Windows NT, UNIX, and Novell Netware. 
     FIG. 4 also represents the processor  420  which is receiving a plurality of GNSS satellite or other public RF navigation/positioning geometrically non-linear signals which are transmitted via transmission path  410 . The processor  420  collects the radio positioning/navigation data elements which include satellite pseudorange, satellite vehicle identification, time tags, GNSS week, GNSS time, GNSS almanac data, longitude, latitude, and altitude, which are contained or derived from satellite signals which are transmitted via transmission path  410 . The processor  420  uses information generated by the GNSS satellite prediction software  520 , and any optional differential data. The data acquired from the DAQ software  510  and the GNSS satellite prediction software  520  is exported directly to the relational database management software  515 . The data is then categorized into appropriate fields of information in various data tables by the relational database management software  515 . 
     The appropriate template or model created for the defined space within a line-of-sight barrier is used by the three-dimensional, parametric, database-driven, graphical software  530  which is driven by data exported by the relational database management software  515 . The three-dimensional, parametric, database-driven, graphical software  530  solves the position/navigation location of mobile receiver/processor  150  operating within line-of-sight barrier  100 . 
     The positioning/navigation location solution data are digitally output via data link  540  in various formats and utilized by other radio positioning/navigation receiver(s) operating within or outside of a line-of-sight barrier, by GIS software, or a host computer database. 
     FIG. 4 illustrates the post processed solution to the position/navigation coordinates (X11, Y11, Z11) of mobile receiver/processor  150  within the line-of-sight barrier  100 . 
     To further understand the calculations and data needed to solve the position/navigation locations of a mobile receiver/processor  150  within a line-of-sight barrier  100  using repeated, geometrically non-linear signals, the following data elements must be determined: 
     constants of time delays (represented by three-dimensional, parametric, database-driven, graphical software  530  as curvilinear parameters) arising from the following: 
     Transmission path from antenna  200  to Identifier/Amplifier/Repeater  115 ; 
     Processing by the Identifier/Amplifier/Repeater  115 ; 
     Identifier/Amplifier/Repeater  115  to broadcast antennae  130 ,  131 ,  132 ,  133  via transmission paths  120 ,  121 ,  122 ,  123 ; 
     location coordinates (represented by three-dimensional, parametric, database-driven, graphical software  530  as earth centered Cartesian coordinates) of the following: 
     GNSS antenna  200  (coordinates are represented by X5,Y5,Z5); 
     Identifier/Amplifier/Repeater  115  (coordinates are represented by X6,Y6,Z6); 
     Broadcast antenna  130  (coordinates are represented with X7,Y7,Z7); 
     Broadcast antenna  131  (coordinates are represented with X8,Y8,Z8); 
     Broadcast antenna  132  (coordinates are represented by X9,Y9,Z9); 
     Broadcast antenna  133  (coordinates are represented by X10,Y10,Z10). 
     The following data element is an optional factor which may be determined when accuracy enhancement is desired: differentially measured variables (time of transmission) for each GNSS satellite  320 . 
     The total signal distance or total time of arrival (TOA) that mobile receiver/processor  150  acquired from the various non-linear signal transmission paths consists of the following equations where T n =elapsed time for signal travel over transmission path n: 
     From satellite  101  to mobile receiver/processor  150  via broadcast antenna  130   
     
       
           T   105   +T   110   +T   115   +T   120   +T   140 =Total TOA from Satellite  101   
       
     
     From satellite  101  to mobile receiver/processor  150  via broadcast antenna  131   
     
       
           T   106   +T   110   +T   115   +T   121   +T   141 =Total TOA from Satellite  101   
       
     
     From satellite  101  to mobile receiver/processor  150  via broadcast antenna  132   
     
       
           T   107   +T   110   +T   115   +T   122   +T   142 =Total TOA from Satellite  101   
       
     
     From satellite  101  to mobile receiver/processor  150  via broadcast antenna  133   
     
       
           T   108   +T   110   +T   115   +T   123   +T   143 =Total TOA from Satellite  101   
       
     
     All of the above data elements are known except for external pseudoranges  105 ,  106 ,  107 ,  108 , and the lengths of transmission paths. Upon the acquisition or prediction of the external pseudoranges  105 ,  106 ,  107 ,  108  by the fixed receiver/processor  160  or satellite position prediction software  520 , the problem will be reduced to one set of unknowns, namely lengths of transmission paths  140 ,  141 ,  142 ,  143  respectively for each of the above equations. Simple subtraction will yield the solution of the unknowns for the length of these transmission paths  140 ,  141 ,  142 ,  143 . 
     Once the external pseudorange  105  from Satellite  101  is known, the distance or total time of arrival from the broadcast antennae  130 ,  131 ,  132 ,  133  to mobile receiver/processor  150  can be determined by the following equations: 
     for Satellite  101 : (via broadcast antenna  130 ) 
     
       
           T   140 =Total TOA from Satellite  101 −( T   110   +T   115   +T   120   +T   105 )  
       
     
     for Satellite  101 : (via broadcast antenna  131 ) 
     
       
           T   141 =Total TOA from Satellite  101 −( T   110   +T   115   +T   121   +T   106 )  
       
     
     for Satellite  101 : (via broadcast antenna  132 ) 
     
       
           T   140 =Total TOA from Satellite  101 −( T   110   +T   115   +T   122   +T   107 )  
       
     
     for Satellite  101 : (via broadcast antenna  133 ) 
     
       
           T   140 =Total TOA from Satellite  101 −( T   110   +T   115   +T   123   +T   108 )  
       
     
     An alternate calculation for the total signal distance or total time of arrival (TOA) that mobile receiver/processor  150  acquired from the various non-linear signal transmission paths consists of the following equations where T n =elapsed time for signal travel over transmission path n: 
     From satellite  101  to mobile receiver/processor  150   
     
       
           T   105   +T   110   +T   115   +T   120   +T   140 =Total TOA from Satellite  101   
       
     
     From satellite  102  to mobile receiver/processor  150   
     
       
           T   106   +T   110   +T   115   +T   121   +T   141 =Total TOA from Satellite  102   
       
     
     From satellite  103  to mobile receiver/processor  150   
     
       
           T   107   +T   110   +T   115   +T   122   +T   142 =Total TOA from Satellite  103   
       
     
     From satellite  104  to mobile receiver/processor  150   
     
       
           T   108   +T   110   +T   115   +T   123   +T   143 =Total TOA from Satellite  104   
       
     
     All of the above data elements are known except for external pseudoranges  105 ,  106 ,  107 ,  108 , and the lengths of transmission paths. Upon the acquisition or prediction of the external pseudoranges  105 ,  106 ,  107 ,  108  by the fixed receiver/processor  160  or satellite position prediction software  520 , the problem will be reduced to one set of unknowns, namely lengths of transmission paths  140 ,  141 ,  142 ,  143  respectively for each of the above equations. Simple subtraction will yield the solution of the unknowns for the length of these transmission paths  140 ,  141 ,  142 ,  143 . 
     Once the external pseudoranges  105 ,  106 ,  107 ,  108  from Satellites  101 ,  102 ,  103 ,  104  are known, the distances or total time of arrival from the broadcast antennae  130 ,  131 ,  132 ,  133  to mobile receiver/processor  150  can be determined by the following equations: 
     for Satellite  101 : 
     
       
           T   140 =Total TOA from Satellite  101 −( T   110   +T   115   +T   120   +T   105 )  
       
     
     for Satellite  102 : 
     
       
           T   141 =Total TOA from Satellite  102 −( T   110   +T   115   +T   121   +T   106 )  
       
     
     for Satellite  103 : 
     
       
           T   142 =Total TOA from Satellite  103 −( T   110   +T   115   +T   122   +T   107 )  
       
     
     for Satellite  104 : 
     
       
           T   143 =Total TOA from Satellite  104 −( T   110   +T   115   +T   123   +T   108 )  
       
     
     The three-dimensional, parametric, database-driven, graphical software  530  determines the coordinates (X11,Y11,Z11) of the mobile receiver/processor  150  located within a line-of-sight barrier  100  by using the following process steps: 
     a. The position of the mobile receiver/processor(s)  150  is represented by earth-centered coordinates (X11,Y11,Z11). These coordinates are determined by intersecting spheres which have radii equal to the internal pseudoranges  140 ,  141 ,  142 ,  143  which emanate respectively from fixed known location broadcast antennae  130 ,  131 ,  132 ,  133 . 
     b. Once that the position (X11,Y11,Z11) of receiver(s)  150  has been solved, the parametric graphical solution software  530  can calculate by using normal three-dimensional vector geometry the calculated pseudoranges  605 ,  606 ,  607 ,  608  from the satellites  101 ,  102 , 103 ,  104  by knowing the earth-centered Cartesian X,Y,Z coordinates of each satellite  101 ,  102 ,  103 ,  104  and the earth-centered Cartesian coordinates of any mobile receiver/processor  150  operating within the line-of-sight barrier  100 . 
     The earth-centered Cartesian coordinates (X11,Y11,Z11) which represent position, or discreet locations which can be averaged over time for navigation purposes or representations, may be transferred via data link  540  in multiple ways to various types of equipment in order to make the positioning/navigation data useful. The following are examples and are not all inclusive: 
     GIS maps for two- and/or three-dimensional positioning and navigational purposes. 
     Host computer with database for positioning and navigational analysis. 
     Broadcast to another mobile receiver/processor  150 . 
     Although the forgoing detailed description of the preferred embodiment of the present invention describes specific use of GNSS satellites, it is to be understood that certain aspects thereof are not limited solely to use with such satellite systems and may be used with signals received from other sources. Two alternative embodiments of the present invention are described in the detailed description of FIGS. 2 and 3. 
     FIG. 2 illustrates an alternative embodiment of the present invention which focus on the use of repeated, geometrically non-linear extensions of simulated GNSS (GNSS) signals, or any radio positioning/navigation signals (RPNS) within a line-of-sight barrier  100 . In the first alternative embodiment of the present invention illustrated in FIG. 2, the SGNSS or RPNS signals are software generated and synchronized using a high grade clock. The satellite signal generator  201  is comprised of a computer/processor  202  with appropriate software that creates SGNSS or RPNS signals. The signal generator is outfitted with software that provides the logic to drive a switching mechanism  205 . After the SGNSS or RPNS signals pass through the switching mechanism  205  they are amplified by a signal amplifier  206 . This software will compute SGNSS or RPNS signal data as if it were received at the fixed location in space of the signal generator  201 . This point simulates a SGNSS or RPNS receiving antenna and is necessary to provide a point of reference for collecting the SGNSS or RPNS data and simulating passing it through a line-of-sight barrier  100 . 
     The signal generator  201  selects a channel to transmit the simulated satellite data via transmission paths  120 ,  121 ,  122 ,  123  to broadcast antennae  130 ,  131 ,  132 ,  133  respectively. These broadcast antennae  130 ,  131 ,  132 ,  133  are accurately surveyed to fixed known locations relative to the user&#39;s choice of system coordinates. The transmission paths  120 ,  121 ,  122 ,  123  will cause individual time delays of the SGNSS or RPNS signals. The transmission paths  140 ,  141 ,  142 ,  143  are direct LOS distances from the fixed, known location, broadcast antennae  130 ,  131 ,  132 ,  133  to the mobile receiver/processor  150  which is operating within a line-of-sight barrier  100 . The mobile receiver/processor  150  with appropriate software, uses the SGNSS or RPNS signals received from the broadcast antennae located at fixed, known locations  130 ,  131 ,  132 ,  133 , via the transmission paths  140 ,  141 ,  142 ,  143  located within the line-of-sight barrier  100  to determine its present coordinates by appropriate triangulation. 
     FIG. 3 illustrates the second alternative embodiment of the present invention. This second alternate embodiment also focuses on the use of GNSS signals or radio positioning navigation signals within a line-of-sight barrier  100 . The combination of a transmitting antenna and signal generator is commonly referred to in the art as a pseudolite. Associated with each pseudolite  230 ,  231 ,  232 ,  233  within the line-of-sight barrier  100  is a satellite signal generator, which comprises a hardware subassembly similar to the signal generation section of a GNSS satellite (commercially available from companies such as Stanford Telecom). The pseudolites are synchronized with a computer/processor  203  outfitted with a high grade clock and power switching mechanism  205 . 
     Computer/processor  203  outfitted with a high grade clock and power switching mechanism  205  distributes power or a signal to initiate power via transmission paths  120 ,  121 ,  122 ,  123  to pseudolites  230 ,  231 ,  232 ,  233  respectively. These pseudolites  230 ,  231 ,  232 ,  233  are accurately surveyed to fixed known locations relative to the user&#39;s choice of system coordinates. The transmission paths  120 ,  121 ,  122 ,  123  will cause individual time delays of the sequenced power distribution. The transmission paths  140 ,  141 ,  142 ,  143  are direct LOS distances from the fixed, known location, pseudolites  230 ,  231 ,  232 ,  233  to the mobile receiver/processor  150  which is operating within a line-of-sight barrier  100 . The mobile receiver/processor  150  with appropriate software, uses the GNSS positioning/navigation signals received from the pseudolites  230 ,  231 ,  232 ,  233 , via the transmission paths  140 ,  141 ,  142 ,  143  located within the line-of-sight barrier  100  to determine its present coordinates by appropriate triangulation. 
     Differential accuracy enhancements are determined and may be applied to the various embodiments of the present invention. These differential corrections provide enhanced accuracy of the positioning/navigation data received within the line-of-sight barrier  100 . The process known as differential positioning compensates for many of the errors which are common in radio positioning/navigation systems. An antenna at a known location receives line-of-sight GNSS signals and broadcasts a signal with current correction adjustments for each satellite which can be received by any differential receiver within its signal range. Location accuracy via GNSS is continually evolving. Standard GNSS receivers can typically produce position estimates within ±60-100 meter accuracy. Sub-meter accuracy of location can be achieved using differential positioning, known as DGPS. 
     The DGNSS base station computes its position based on the current satellite data it is receiving. This computed position is compared to the known position of the DGNSS antenna. The time differences are calculated for each satellite currently in line-of-sight. These corrections are transmitted to any DGNSS receiver/processor for enhanced accuracy. 
     While certain embodiments of the system for providing GPS signals to receiver/processors operating within a line-of-sight barrier are described in detail above, it is contemplated that variations and modifications will be developed within the teaching of the present disclosure.

Technology Classification (CPC): 6