CN1152262C - System and method for locating a mobile wireless communication transceiver - Google Patents

Abstract

The present invention relates to a method and a device for positioning a mobile wireless communication transceiver in a cellular phone or a honeycomb type communication system. The method uses a simplified system to passively monitor signals transmitted by a transceiver, and two receiving base stations can determine arrival time marks of the signals of the remote transceiver; then, the time mark information and the subsidiary position sensitive information are combined to determine the possible position of the transceiver. The present invention has special adaptability for road transport. Because the present invention is helpful to enhance emergency service and roadside aid in response to call aid, the traffic flow can be monitored passively.

Description

System and method for locating a mobile wireless communication transceiver

technical field

The present invention relates to determining the geographic location of a mobile wireless communication transmitter as part of a wireless cellular communication system to facilitate emergency services response, roadside assistance, traffic monitoring, or other services where applicable or supported by location information.

Background technique

Currently, cellular telephone systems provide rapid communication using wireless telephones. Cellular telephones typically operate on an analog system of Frequency Division Multiple Access (FDMA). Digital technologies, including Time Division Multiple Access (TDMA) or Code Division Multiple Access (CDMA), provide greater capacity and allow more individuals to use cellular phone service at the same time. In addition, "cellular" communication systems, such as Personal Communication Systems (PCS), can further increase the number of people using wireless communication networks.

A cellular telephone or cellular communication system is a system with a network of fixed base stations serving a local area ("cell") that hosts a number of mobile transmitter/receiver ("transceiver") components, known as cellular Telephone, providing comprehensive communication services. Such communication networks attempt to communicate with each transceiver from the base station, which provides the best communication. The best base station is usually, but not necessarily, the one closest to the mobile transceiver. In order to provide optimal communication support, the network does not need to pinpoint the geographic location of the mobile transceiver, but more needs to determine which base station to use.

The inability of existing communication networks for cellular telephones or cellular communication systems to accurately determine the location of mobile transmitters is a major shortcoming in emergency services. For example, public safety officials in Los Angeles estimate that one in four people who call emergency numbers (“9-1-1”) on a cell phone currently do not know their location, noting that more than 60 percent of traffic disasters in the U.S. Happened on a country road. Delays due to location uncertainty compound the long response times inherent in providing emergency services in rural areas.

Over the years, the problem of locating mobile radio transceivers has been solved in a variety of ways, not including cellular telephones or cellular communication systems. A viable, simple, low-cost solution for large-scale surveillance of mobile phones has not been found. A practical difficulty in implementing any type of mobile wireless transceiver location is the cost of required modifications to the transceiver or communication network (infrastructure) used to determine the location of the mobile transceiver. It is also rare, if ever, to use any of the designated transceivers to request emergency or roadside assistance. Therefore, transceiver suppliers and communication network operators have little economic incentive to increase the complexity (and cost) of transceivers or to install extensive and expensive infrastructure to support these rarely used services in the absence of government mandates. Even if it doesn't make money in the short term, the value of emergency assistance and roadside assistance services undoubtedly has value in providing and enhancing personal and public safety. The use of mobile communication systems to ameliorate the increasing incidence of violent incidents and growing concerns about personal safety is a respectable policy goal and has the potential to realize enormous benefits for subscribers, network operators and the general public. However, recognizing that the aforementioned goals are so important and so valuable, a practical, inexpensive infrastructure is needed to uniquely identify citizens requesting or reporting need for assistance, communicate with them, and provide response assistants with their location.

Technology exists to pinpoint a person's location in applications other than providing emergency or roadside assistance. For example, the satellite-based Global Positioning System (GPS), utilizing dedicated receivers for wireless GPS signals broadcast by the satellites, enables the location of locations where the GPS signals are received to be determined. However, using GPS to obtain the location of a communications transceiver requires that the mobile transceiver contain a GPS receiver. And GPS receivers are expensive. Even if its cost can be reduced through mass production, there is still a need to integrate GPS receivers with existing and future mobile transceivers. Considering how little this service is used, especially in light of the enormous number of mobile transceivers already in use within the United States and abroad that require location capability, the costs associated with the above scheme appear to be prohibitively high.

Techniques also exist for determining the location of a mobile communication transceiver by passively monitoring its wireless emissions. In the simplest method, however, wireless positioning does not take into account distortions in the apparent position due to multipath interference (multipath processing techniques). Multipath processing involves radio signals bouncing off objects such as cars, buildings, and hillsides. If the above effects are not considered, the apparent position of the transceiver will be distorted. For short-wave, wireless communications, multipath propagation is common because relatively small objects can reflect a large number of transmitted signals, especially in cities with many buildings that reflect signals. Therefore, potential multipath-induced distortion in the apparent position of mobile transceivers is a problem that must be addressed in passive location radio transmitters to support applications such as providing emergency or roadside assistance.

While signal analysis and source localization procedures are used to refine potential distortions in the apparent position, the multipath propagation environment does not necessarily prevent the localization of the transceiver. For example, US Patent No. 4,728,959 to Maloney et al., shows how to apply a direction finding process with which the direction of arrival (DOA or AOA) of a signal can be measured by means of two or more receiving base stations. Determining location using the passive monitoring of communication signals described in this patent is an exceptional application because it enables the determination of the location of a mobile transceiver in a network service area with at least two receivers of known locations stand. This method of direction finding is simple and accurate, but requires directional antennas at each receiving station. Also, taking into account multipath effects, the need for directional antennas can be alleviated by using Time Difference of Arrival (TDOA) measurements, which can be obtained with omnidirectional antennas and accurate time base maintenance equipment. Positioning using TDOA measurements requires reception at three or more locations, since only one TDOA measurement can be made per pair of locations, and each TDOA measurement only determines the hyperbola (two-dimensional) where one transmitter is located. Even in environments affected by multipath, the transmitter position can be obtained by analyzing the TDOA measurements of the receive position with at least one triplet. However, the need to utilize time maintenance equipment to jointly receive a common signal at three or more locations adds complexity and cost to the TDOA approach beyond what some cell phone or PCS companies are currently or willing to accept.

Typically, in addition to time stamp and orientation data that can be derived from received signal characteristics, other information related to the location of the mobile radio transceiver can be derived or obtained. For example, in a system designed to provide roadside emergency assistance, we can assume that the person requesting assistance is in a vehicle on or close to a road. Such assumptions can be tested, for example, by asking the person to speak if he or she is on the road. Such additional geographic or topological information, referred to herein as "ancillary information," is generally available to dispatchers. By combining auxiliary information with time-stamped information from two (rather than three or more) base stations, it is sufficient to determine the range of the location of the mobile radio so that emergency and roadside assistance services can be dispatched. Obtaining the location of the transceiver based only on the observed characteristics of the radio transmissions received at the two locations is sufficient, making the need for additional base station information to obtain the location redundant. However, no attempt has been made so far to use such ancillary information to make the need for additional base stations superfluous.

Monitoring mobile transceivers located on vehicles has many advantages over merely providing support for responding and requesting services. One advantage is the ability to monitor traffic flow at a high cost performance ratio. Unexpected traffic events ("traffic jams") block highways, thereby having detrimental effects on safety, the environment, and the economy. Telegram traffic in a large city is a class of ancillary information that can be combined with observed information related to position and velocity, as well as topographical information (e.g., driving maps) to indicate which roads are passable and which traffic crowded. However, traffic flow information, emergency services, and roadside assistance are not the main reasons for establishing a communication system, so the communication system does not currently provide such services. The cost of adding equipment to the communications infrastructure to provide traffic flow information is justified to the communications company only if it can be achieved with minimal additions to the infrastructure.

Currently, technologies exist that provide a partially comprehensive solution to the problem of providing geographic location with sufficient accuracy to assist emergency and roadside assistance personnel. However, such systems rely on observation information obtained from two or more directional receptions, and three or more receptions of time-stamped wireless transmissions, or navigational information from devices unrelated to the communication transceiver. No system has attempted to obtain location information by combining observed time-stamped information obtained from only one pair of wireless communication receptions with ancillary information such as obtained from street maps. It is therefore an object of the present invention to provide a simple and efficient way to identify and determine the location of a mobile radio transceiver in any wireless communication system, including existing or desired, such as those used in personal communication systems ( PCS), cellular telephones, dedicated mobile radios (SMRs), and personal digital assistants (PDAs). It is an object of the present invention to provide an automatic location identification (ALI) and an automatic " Digital "Identification (ANI), ALI and ANI facilitate domestic and international, rural and urban emergency notification and personal safety, and highway surveillance.

Contents of the invention

Another object of the present invention is to provide a system in which location and identification are inexpensively provided as a communication adjunct for domestic and international wireless Enhanced 9-1-1 (E9-1-1) emergency and daily roadside assistance notification; estimate road speed and provide transit information such as traffic congestion and flow characteristics; provide the above capabilities in a system that is both relatively easy to deploy and inexpensive to build; provide a system with a transportable configuration, Therefore, it can be used temporarily to monitor fixed areas, such as road construction areas, or places for special events such as sports competitions, conferences or concerts; providing a combination of processes and attributes in the form of an adjunct to a communication system, forming Inexpensive and robust positioning and identification system.

The present invention provides an apparatus for determining the position of a mobile radio communication transceiver in a radio communication system, the apparatus comprising two sensor stations of known location, each sensor station having a A receiving antenna for wireless signals, a clock mechanism such as a GPS-based receiver to maintain an inter-station synchronized time standard, and a signal characterization processing unit for determining the difference between the wireless signals transmitted by the mobile wireless transceiver to the sensor station time-of-arrival (TOA) of specific components, a source of ancillary information about other signal characteristics of the mobile transceiver or the operating environment, a multidimensional parameter correlation processing unit for determining the probable location of the mobile transceiver based on the TDOA and associated ancillary information, and an output device representing the probable location of the mobile transceiver.

The present invention provides a simplified system for determining the location of a mobile radio transceiver in a cellular telephone or cellular communication system using passive monitoring of signals transmitted by a mobile transceiver. In the present invention, the TDOA trajectory (ie, two-dimensional hyperbola) of the mobile transceiver location is determined by receiving the processing by the base station at two known locations with inter-station synchronization. This TDOA trajectory is then combined with the accompanying information to determine the probable location of the transceiver. The invention is particularly suitable for road transportation because it facilitates emergency (9-1-1) services and roadside assistance, and it allows passive monitoring of traffic flow. Ancillary information includes location information obtained from other non-wireless location methods. Such information may include topological information of the traffic map in the area of the base station, or other information such as the derived speed of the transceiver, if available, or information obtained from the caller's personal communications or from equipment located at the caller's location .

The present invention does not need to determine position by combining two or more equivalent hyperbolas from three or more base stations; two base stations are sufficient. This capability is particularly useful in CDMA communication networks where enhanced capabilities are obtained through dynamic power control such that fewer base stations are likely to receive transmissions from transceivers. Nevertheless, the present invention does not prevent the use of more than two base stations to further confirm the accuracy of the position, or to determine the position of a mobile radio transceiver without available adjunct information. Being able to determine position from two locations using the TOA/TDOA method is particularly advantageous for emergency assistance in more environments where two-site reception can be applied, requires less infrastructure, and can greatly reduce costs. The invention is particularly useful for monitoring traffic flow in rural areas where few roads have cellular facilities close to the road and it is highly unlikely that signals will be captured in three or more locations. Therefore, in rural areas, the location of mobile transceivers along the observed TDOA trajectory (hyperbola) can be better represented by ancillary information in the form of route topology. The present invention also provides methods and apparatus for determining the position of a mobile radio transceiver in a radio communication system, methods and apparatus for determining the TDOA trajectory of a mobile radio communication transceiver, and for combining ancillary information with the TDOA trajectory A method and apparatus for determining the location of a mobile wireless transceiver wherein the wireless communication system includes two or more sensor stations of known location.

According to the present invention, there is provided a system for locating a mobile radio communication transceiver in an operating environment served by a radio communication system, comprising: first and second sensing stations of known position, each sensing station receiving A radio signal from the mobile transceiver; a time stamp (timing) processing unit, which determines time difference information of signal arrival based on the radio signals received at the first and second sensor stations; and a position processing unit, which determines the time difference information based on The auxiliary information and the time difference information of signal arrival determine the possible location of the mobile transceiver, wherein the auxiliary information is related to the location of the mobile transceiver.

According to the present invention, there is provided a method for locating a mobile transceiver in a wireless communication system comprising first and second sensor stations, the method comprising the steps of: (a) Two sensor stations receive radio signals from the mobile transceiver; (b) access ancillary information related to the location of the mobile transceiver; (c) determine the location of signal arrival based on the radio signals received at the first and second sensor stations time difference information; and (d) determining the possible location of the mobile transceiver based on the time difference information of signal arrival and ancillary information.

The present invention has the advantage that the location of a mobile wireless transceiver can be determined without requiring special equipment, such as a GPS receiver, to be embedded in or integrated with the mobile transceiver. In fact, the present invention is capable of locating all existing cellular phones. The cost of deploying the positioning system of the present invention is relatively low. Low start-up costs mean that the system can be deployed quickly so users can realize its benefits sooner and at lower cost.

Description of drawings

Figure 1 shows the location of a cellular telephone transceiver obtained by utilizing the present invention to correlate time difference of arrival (TDOA) information with road location information inherent in a road network map.

FIG. 2 shows an enlarged view of the intersection of the TDOA line shown in FIG. 1 with the road of interest.

Figure 3 illustrates the functional components of a system capable of combining TDOA and other signature information with ancillary geographic information obtained from other sources to obtain the location of a wireless transceiver for standard communication operations.

Figure 4 shows the intersection display of TDOA data measurements and roads traveled by the cell phone in use, enabling its speed to be calculated and its direction of movement to be estimated.

FIG. 5 shows the configuration of a system to which the functions described in FIG. 3 are applied.

Detailed ways

Figure 1 shows how the invention determines the location of a mobile transceiver. Figure 1 shows ancillary information in the form of a street map of a portion of Annandale, Virginia, USA, and a mobile radio transceiver in the form of a cellular telephone. Vehicles equipped with cellular phones are located in the area marked number 1 along highway 2 . A series of TDOA trajectories 3 at different times were determined using sensing stations located at positions 10 and 11.

The TDOA track 3 is superimposed on topological data 20 representing the street map of the area. Vectorized map data for urban areas are readily available, for example, from ETAK, Menlo Park, CA; Navigation Technologies, Sunnyvale, CA; Roadnet Technologies, Timonium, Maryland; or the U.S. Department of Commerce Population Obtained by the Census Bureau. These maps represent ancillary information in the form of the topology of the area in which mobile radios operate. The present invention seeks to use such ancillary information to allow the control station (located at location 12 in FIG. 1 ) to determine the location of a mobile radio transceiver operating in Area 1 using TDOA trajectories and ancillary information obtained from two sensor stations.

FIG. 2 shows an enlarged view of the location area 1 shown in FIG. 1 . TDOA Track 3 is indicated as the intersection of Parkwood Terrace and Marc Drive. From any of the TDOA traces 3, it is not possible to determine which street the mobile transceiver is located on. Any two TDOA trajectories, however, provide TDOA variations corresponding to certain geographic distances covered by mobile transceivers in Area 1 . By recording the time at which each TDOA trajectory is measured, the control system 12 is enabled to determine the approximate passing speed of the mobile transceiver in area 1 . For a cell phone that is communicating, a higher passing speed, such as 80km/hr (50mph), means that the mobile transceiver is on a highway arterial 2, rather than on a residential street where road signs The speed limit is 40km/hr (25mph), which is half the speed observed. Thus, by applying additional information about signposted speed limits or in the form of the average speed distribution of the roads shown in FIG. 2 , the control station 12 is able to deduce on which street to place the possible location area 1 .

In the above example, the control station 12 does not appear to be able to determine whether the mobile transceiver is on the highway 2 or on the street based solely on the TDOA trajectory unless the transceiver is also moving at a very high speed. For the location of stationary transceivers, emergency (9-1-1) assistance will require some other form of ancillary information. For example, a dispatcher offering assistance could obtain additional information by asking whether the party requesting assistance is on a major road, and if not, seeking other forms of descriptive information, such as street names or features to distinguish secondary streets. If the geographic information inherent in the request data described above is combined with the location information from the TDOA measurements, it is possible to estimate the location of the transceiver.

Furthermore, even non-moving is important for other purposes such as monitoring traffic flow. Based on common traffic characteristics, the control station 12 can assume that the majority of cell phone calls from Area 1 originate from Arterial Highway 2 . The transponder shall prominently display the ground speed corresponding to the signposted limit for that highway. If the characteristic speed observed for this transceiver is significantly lower than the speed under normal road conditions in or around Area 1, then this information suggests that Arterial Highway 2 is abnormally congested. If an accident is believed to have occurred, traffic warnings indicating congestion may be issued, and emergency or other service vehicles may be dispatched to investigate the cause of the congestion. The above functionality does not require additional information beyond time stamping of the different TDOA trajectories and knowledge of normal road characteristics, but if any such information is available, it can always be added.

Figure 3 shows a block diagram of a system implementing the invention. The sensor subsystem 30 includes an RF antenna 31 connected to a signal characterization processing component 32 . The RF antenna 31 may be an existing communication antenna. A signal characterization processing component 32 identifies the time of RF signal measurements obtained according to an inter-station synchronized time-stamping standard, such as a GPS receiver. The sensor system passively receives radio frequency signals generated during normal use of the wireless communication system 34 and converts them into information for the control system 35 described below. This information includes the time of arrival of the signal component being processed, the representation of that component (if required) and the identification of the transceiver. This information can also include observed location-related characteristics such as direction of movement or rate of change in TDOA (relative Doppler shift), signal strength, direction of signal arrival or rate of change, and Two-way signal propagation time in tightly controlled transceiver communication systems of signal bandwidth. By extending the duration over which the captured signal is analyzed (ie the integration time or "dwell" time), this process can yield a measure of the rate of change of TDOA (ie relative Doppler shift) as well as TDOA itself. The above-mentioned rate of change can be detected from an extended measurement procedure, since the standard assumption of fixed TDOA during the measurement procedure will be invalid and will produce degraded measurements when receiving signals from perceptibly mobile radio transceivers. The rate of change of TDOA is related to the vertical movement speed of the communicating transceiver. As an additional measure of transceiver position, the characterization process can determine the received signal energy (ie, the variance or mean square of the unbiased signal level). Signal energy indicates (by means of signal propagation estimates discussed below) the range or distance from the receiving location to the mobile transceiver, and the rate of change of signal energy or other energy change characteristics can indicate not only the radial velocity of the transceiver but also the Physical obstruction or cause of multipath interference due to accompanying signal propagation from a known area. The unimpeded two-way signal propagation time is proportional to twice the time from the receiving location to the location of the mobile transceiver. All physical characteristics measured from the received radio signal form the basis of the positioning process, where the measurements have a known relationship to the guessed transceiver position and movement.

Measurement time and uncertainty information is collected from the two sensor stations and then inserted into the multidimensional parameter correlation processing part 36 . The processing component 36 combines the time stamp information with other ancillary information from the input 32, 37 or 38 to determine the position of the vehicle. The phrase "ancillary information" should be used to enhance the observed characteristics of the time-stamped data, and also includes information obtained from sources other than the wireless transmission of the mobile wireless transceiver. Ancillary information includes information about the environment in which the mobile transceiver is considered to operate, such as the configuration of the road network, terrain features and boundaries, signal propagation characteristics, information about the weather and its impact on signal propagation and the road traffic environment, including Dictated or other descriptions of highway numbers, road names, speeds, nearby features, or other location-sensitive information from mobile transceiver communications. Road and terrain representation data for use in geographic information system mapping databases can be obtained from the above-mentioned designated vendors. Additional data representing posted speed limits for road sections included in the database are also usually available from map data producers or state government departments of transport. In addition, typical speed distributions of traffic on various road sections as a function of time, weather conditions, day of the week, and season can often be obtained from traffic flow studies routinely conducted by state departments of transportation. On the other hand, from the traffic statistical information collected on specific occasions using the present invention, such data representing the relationship between position and traffic flow can be accumulated, and then recursively updated, so as to obtain more rapid, More robust decisions. The relationship between signal strength (ie energy) and distance is supporting information, which can be obtained in the database when the ancillary data characterizes the signal propagation. The standard relationship between strength and distance is that the received signal strength (ie energy) is inversely proportional to the square of the range. However, in multipath environments typically characterized by short-wave communications, such as cellular systems, strength typically scales inversely with distance to the second power and is highly dependent on the direction of signal arrival and weather conditions. Therefore, the use of signal strength as a range indicator depends on the accuracy of the database of ancillary information representing the distance transform of the signal, ie the signal propagation characteristics. For an approximate correlation measure of the ratio of signal power to the estimated distance from the receiver to the mobile transceiver, signal propagation analysis can apply static or dynamic projections of RF propagation measurements. Computer software to facilitate such signal propagation projections is available from Applied Spectrum Research, Boulder, CO; C.E.T. Corporation, Edgewater, FL; SoftWright, Denver, CO; or H2A Communications, Moscow, ID. Propagation analysis is free to take into account weather effects, ground topography and construction, building heights, and direction-dependent interference or background noise.

Knowledge of terrain conditions along the approximate path of signal arrival can be used to estimate their effect on signal propagation. In addition, geographic features such as hills, water boundaries, etc., can limit the area in which a transceiver can be placed in a known manner. Thus, such topographical information may also be used as side information to enhance the efficiency and accuracy of position determination.

In rural areas, it is expected that the combination of TDOA information with topological map matching (i.e., matching location information with known geographic information of roads or other features of the terrain) form ancillary information will be sufficient in most cases to monitor traffic along arterial traffic flow while facilitating the dispatch of emergency vehicles and roadside assistance. Rural areas have fewer roads, so the TDOA traces of two sensor stations and the intersection of the mobile radio are sufficient to uniquely identify the probable location of the mobile radio.

In urban areas, we believe that the use of time-stamp information and road traffic map information, by itself, does not appear to be sufficient to uniquely determine the location of a mobile radio. In this case, additional information may be required. The present invention contemplates the use of ancillary information in the knowledge-based location information processor 38 . Processor 38 is capable of integrating information from additional sources, such as geographic representations of the emergency assistance (9-1-1) center operator's knowledge and judgment regarding the apparent or probable location of the mobile wireless transceiver.

The present invention also contemplates receiving supporting descriptive information from a wireless communication system. The location-related information extracted from the received RF signal may be augmented with ancillary information from the wireless communication system 34 shown in FIG. 3 . For example, RF antenna 33 may be a base station of a cellular telephone system that is closest to a remote transceiver, ie, a cellular telephone. Wireless communication system 34 attempts to demodulate communications from remote transceivers. The descriptive information received through the wireless communication system may include location knowledge, such as a factual voice description sent from a vehicle on the road to describe the name of the road on which the mobile transceiver is driving. Used as ancillary information in the relative location processing of TDOA measurements. In the case of a request for assistance, such as a 9-1-1 call, the answering operator typically asks the person to access the call to identify their calling number and location. Callers, who do not know their location, can describe their environment over the phone. Accordingly, the present invention is designed to assist an operator in quickly providing an accurate location by utilizing information that the operator can quickly derive. With the road number or street name from the caller, the probable location of the caller is quickly provided by concatenating that road with the estimated signal time difference of arrival. When the caller does not know the road they are crossing, the assisting operator can request information about the speed of travel and nearby more prominent features. All such location-related information, whether obtained manually or through automated analysis, can be converted into geographic form, either through graphical interaction or automated geographic interpretation, for inclusion in evaluations related to the extracted signal features.

The input of geographic knowledge or the understanding of the operator's or human's source of information can be aided by graphical interaction between a human and a workstation terminal equipped with a graphical pointing device for automatic pointing determination. By viewing a computer-driven map display of related highway areas, the operator is able to use a graphical input device to select an approximate location, a highway identified by the caller's voice, or an ellipse or polygon based on a communication description. United States Geographical Survey Specialty Paper 1395, titled "Map Projections—A Workbook," by John P. Snyder, incorporated herein by reference, illustrates the relationship between planar projected coordinates used in geographic displays and surveyed reference coordinates used in navigation and positioning reference systems The position between represents the mathematical transformation of the conversion.

On the other hand, the operator may provide textual input of conveyed or inferred highway names, speeds, features or road intersections which may be communicated or in response to operator inquiries. The text data is then converted to approximate location information by transformation using a text location synthesis transformation database contained in an addressing database such as a United Parcel Service map, or a 9-1-1 database of a public service response center. In advanced system implementations, relevant information may be requested under the automatic control of speech synthesis, or through computer interaction with a processor integrated into the vehicle or user communication device, and may be processed through speech recognition, or used to extract The time-stamped and related feature measurements enter a direct data interface for correlation processing to analyze the response.

The multidimensional parameter correlation processing part 36 in Figure 3 combines the different parameter information from the inputs 32, 37 and 38 to generate a probabilistic description of the location and movement of the mobile transceiver. The knowledge representation of input information and its uncertainty can take many forms, such as discrete attribute vectors, where each element of the vector represents the value of a specific discrete attribute, which can be Boolean, integer, floating point, or symbolic, and Specifically chosen values will have an associated confidence level; a continuous numerical parameter with respect to statistical error; and/or a fuzzy logic parameter. The correlation process can use numerous engines and uncertainty management systems, each suitable for appropriate knowledge representations, such as maximum likelihood or least squares estimation, joint probabilistic data association algorithms, probability density functions for continuous parameters multi-object tracking systems a multi-hypothesis uncertainty management system; a rule-based expert system with multi-confidence production rules combining discrete logic assertions with continuous numerical information; a fuzzy logic engine; and a causal trust network.

As an example of related processing, consider the following situation. It is detected that a certain transceiver is moving along a road in an urban area where the road information is not known, but some nearby features are known. TDOA trajectories with associated location confidence segments can be found to intersect numerous roads, features, rivers, and bodies of water, for example, by scanning these objects and subsequent pixel coverage detection, and then interrogating the database of these objects to find candidate The candidate object for intersection or close to the intersection of TDOA trajectory and other objects, such as the object closest to the intersection of TDOA trajectory and road. The results of the above queries are captured in an appropriate knowledge representation. Through uncertainty management, applying constraints derived from cell location or other more specific a priori ranges of signal strength, or from the caller's description of nearby features, can reduce the likelihood or confidence of certain candidates, while Increase the likelihood or confidence of other objects.

FIG. 4 shows how information obtained from successive measurements of signal time difference of arrival is used to calculate the velocity and direction of a mobile radio 40 moving south along a restricted access road (shown as Interstate 495). An operator or processor indicates intersections of TDOA trajectories with designated roads (map matching). The processor calculates the average velocity between successive points. The rate of change of the time difference of arrival of the signal from the mobile transceiver 40 is proportional to the velocity component of the transceiver which is orthogonal to the TDOA trajectory of the receiver and the mobile transceiver. Using the projection of this component on the tangent direction between the TDOA trajectory on the selected road and the road intersection, the corresponding speed and moving direction can be estimated. On the other hand, by continuously observing the time difference of arrival and evaluating the movement of the implication intersection with the alternative road trajectory, the movement parameters can be estimated more precisely. By correlating with a suitable representation of the road network speed distribution, and further estimating the probability of the estimated speed that each alternative road could reasonably occur, it is more possible to estimate the actual road along which the mobile transceiver will travel.

Devices useful in the present invention may include general purpose processing devices such as microprocessor workstations based on Intel 80486 or Pentium central processing units (CPUs) or Motorola 68040 or PowerPC CPUs. Correlation calculations will determine the best combination of time stamps and other possible characteristics of measurements, transport information, and/or human estimates using supporting ancillary information stored on mass storage such as disk, CD ROM, bubble Storage and tapes such as are commonly found in workstations and similar database servers. For rapid access to large volumes of geographic data of various types, high-utilization mass storage devices should be connected to data processing via high-throughput data communication paths, such as direct processor bus disk interfaces and Ethernet interprocessor networks equipment.

Figure 5 shows an implementation of the invention applied in a manner of monitoring traffic flow using an existing cellular telephone network as a wireless communication system. The purpose is to use the mobile transceiver 40 as a probe to determine the flow of traffic along the road 51 . A typical cellular telephone 40 transmits radio frequency signals which are intercepted by receivers 32 located at sensor stations 10 and 11 . Information relating to the time stamps of signal capture and other observed signal characteristics are then preferably transmitted to a control station or traffic control center 53 - transmitted time stamps and other characteristic information should be more accurate than received signals or other such underlying data have Higher priority to minimize the amount of information transmitted. Process the TDOA and related information, and then display the above information on the monitor 54 of the computer, as well as other useful information obtained therefrom, such as the passing speed of the vehicle on the highway 51 .

The principles, best mode and mode of operation of the invention have been set forth in the foregoing specification. The embodiments disclosed here should be interpreted as illustrating the present invention, not as limiting it. The above disclosure is not intended to limit the range of equivalent structures available to one of ordinary skill in any way, but rather to expand the range of equivalent structures in ways not previously imagined. Various changes or modifications may be made to the above-described illustrative embodiments without departing from the scope and spirit of the invention as set forth in the appended claims.

Claims (30)

1. one kind is used for providing the running environment of service to locate the system of mobile radio telecommunications transceiver at wireless communication system, comprising:

The first and second sensing stations of known location, each sensing station receives the radio signal from mobile transceiver;

A time mark processing element, these parts are determined the time difference information that signal arrives according to the radio signal that receives at the first and second sensing stations; And

A position processing element, these parts are determined the possible position of mobile transceiver according to the time difference information of satellite information and signal arrival, and wherein satellite information is relevant with the position of mobile transceiver.

2. the system of claim 1, wherein

The first sensing station comprises one first signal characterization processing element, and these parts are determined the very first time information with corresponding signal arrival of the time that receives radio signals at the first sensing station;

The second sensing station comprises secondary signal characterization parts, and these parts are determined second temporal information with corresponding signal arrival of the time that receives radio signals at the second sensing station; And

Described time mark processing element according to the very first time information of signal arrival and second temporal information of signal arrival, is determined the time difference information that signal arrives.

3. the system of claim 1, wherein satellite information comprises database information.

4. the system of claim 1, wherein satellite information comprises the signal propagation characteristic of the running environment of mobile transceiver.

5. the system of claim 1, wherein satellite information comprises that the user of wireless communication system describes.

6. the system of claim 1, wherein satellite information comprises the physical features of the radio signal of measurement, and does not comprise the signal time label information.

7. the system of claim 6, wherein the physical features of Ce Lianging comprises signal strength information.

8. the system of claim 6, wherein the physical features of Ce Lianging comprises the arrival direction from the signal of mobile transceiver.

9. the system of claim 1, wherein satellite information comprises the bilateral signal propagation time.

10. the system of claim 1, wherein satellite information comprise mobile transceiver running environment signal propagation characteristic, magnitude of traffic flow feature, wireless communication system user's description, topology information, standard routes information, cartographic information and convey a message at least one.

11. the system of claim 1, wherein the time mark processing element is determined the time difference information that a plurality of signals arrive.

12. the system of claim 11 also comprises the device that moves of determining mobile transceiver according to the time difference information of a plurality of signals arrival.

13. the system of claim 11 also comprises the device of determining the time difference rate of change information that signal arrives according to the time difference information of a plurality of signals arrival.

14. the system of claim 11 also comprises the device of determining the road monitor message according to the time difference information of a plurality of signals arrival.

15. the system of claim 1, wherein the possible position of mobile transceiver is used for the road supervision.

16. a method that is used at wireless communication system location mobile transceiver, this wireless communication system comprises the first and second sensing stations, and this method may further comprise the steps:

(a) in the radio signal of first and second sensing stations reception from mobile transceiver;

(b) the visit satellite information relevant with the position of mobile transceiver;

(c), determine the time difference information that signal arrives according to the radio signal that receives at the first and second sensing stations; And

(d), determine the possible position of mobile transceiver according to the time difference information and the satellite information of signal arrival.

17. the method for claim 16, wherein step (c) may further comprise the steps:

(i) definite very first time information that arrives with corresponding signal of the time that receives radio signals at the first sensing station;

(ii) determine second temporal information with corresponding signal arrival of the time that receives radio signals at the second sensing station; And

(iii), determine the time difference information that arrives according to the very first time information of signal arrival and second temporal information of signal arrival.

18. the method for claim 16, wherein satellite information comprises database information.

19. the method for claim 16, wherein satellite information comprises the signal propagation characteristic of the running environment of mobile transceiver.

20. the method for claim 16, wherein satellite information comprises that the user of wireless communication system describes.

21. the method for claim 16, wherein satellite information also comprises the physical features of the radio signal of measurement, and does not comprise the signal time label information.

22. the method for claim 21, wherein the physical features of Ce Lianging comprises signal strength information.

23. the method for claim 22, wherein the physical features of Ce Lianging comprises the arrival direction from the signal of mobile transceiver.

24. the method for claim 16, wherein satellite information comprises the bilateral signal propagation time.

25. the method for claim 16, wherein satellite information comprise mobile transceiver running environment signal propagation characteristic, magnitude of traffic flow feature, wireless communications method user's description, topology information, standard routes information, cartographic information and convey a message at least one.

26. the method for claim 16 also comprises the time difference information of determining that a plurality of signals arrive.

27. the method for claim 26 also comprises the step that moves of determining mobile transceiver according to the time difference information of a plurality of signals arrival.

28. the method for claim 26 also comprises the step of determining the time difference rate of change information that signal arrives according to the time difference information of a plurality of signals arrival.

29. the method for claim 26 also comprises the step of determining the road monitor message according to the time difference information of a plurality of signals arrival.

30. the method for claim 16 comprises that also the possible position that uses mobile transceiver carries out the step that road monitors.

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