`United States Patent
`[191
`
`Sheffer et al.
`
`11111111111111111 lllli 1111111111111111111111111 lllll lllll 111111111111111111
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`
`
`
`
`
`US005218367 A
`
`[11]Patent Number:5,218,367
`[45]Date of Patent:Jun. 8, 1993
`
`[54]VEHICLE TRACKIN� SYSTEM
`
`343/457 4,596,988 6/1986 Wanka .................................
`
`
`3/1987 Gray et al. .......................... 342/457
`4,651,157
`[75]Inventors: Eliezer A. Sheffer; Marco J.
`
`
`
`
`
`4,740,792 4/1988 Sagey et al. ......................... 342/457
`
`
`Thompson, both of San Diego, Calif.
`
`
`4,891,650 1/1990 Sheffer ................................ 342/457
`
`
`
`4,907,290 3/1990 Crompton .......................... 455/33.1
`
`
`
`5,055,851 10/1991 Sheffer ................................ 342/457
`
`
`
`
`5,121,126 6/1992 Clagett .............................. 379/59 X
`
`[73]Assignee:
`
`
`Trackmobile, San Diego, Calif.
`
`[21]Appl. No.: 891,805
`
`[22]Filed:Jun. 1, 1992
`
`[56]
`
`
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`FOREIGN PATENT DOCUMENTS
`0011444 5/1980 European Pat. Off . .
`[51]Int. CJ.5 ........................ GOlS 3/02; H04M 11/00
`
`
`
`
`0242099 10/1987 European Pat. Off . .
`379/59
`[52] U.S. CI •.......................................
`342/457;
`
`
`
`2016770 9/1979 United Kingdom .
`
`342/457, 463; 455/33.
`
`
`[58]Field of Search ............... l;
`
`
`
`2207787 2/1989 United Kingdom .
`
`379/58, 59, 63
`Primary Examiner-Mark Hellner
`
`
`
`
`
`
`Attorney, Agent, or Firm-Brown, Martin, Haller &
`McClain
`
`
`2,204,438 6/1940 Neufeld ................................... 250/2
`[57]
`ABSTRACT
`
`
`2,922.142 1/1960 Lappin ................................ 340/150
`
`
`
`A vehicle tracking system makes use of a conventional
`
`
`1/1962 Kleist et al. .......................... 343/6.8
`3,018,475
`
`
`
`
`3,058,106 10/1962 Cutler .................................. 343/100
`
`
`
`
`
`cellular telephone network including a plurality of fixed
`
`
`
`3,137,854 6/1964 Anderson ............................ 343/112
`
`
`
`
`cellular transmitter sites each covering a predetermined
`
`Slifer, Jr .............................. 343/100
`
`3,357,020 12/1967
`
`
`
`area. The system includes a plurality of cellular signal
`
`
`
`
`3,419,865 12/1968 Chisholm ............................ 343/112
`
`
`
`processing units for installation at hidden locations in
`
`
`
`3,518,674 6/1970 Moorehead et al. ............... 343/112
`
`
`
`
`vehicles to be monitored. Each unit is connected to one
`
`
`
`3,531,801 9/1970 Huebscher ............................ 343/15
`
`
`
`3,680,121 7/1972 Anderson et al. .................. 343/112
`
`
`
`or more different sensors in the vehicle, at least one of
`
`9/1972 McMurray ......................... 179/5 R
`3,694,579
`
`
`
`
`the sensors being a break-in detector for detecting tam­
`
`
`
`3,793,635 2/1974 Potter .................................. 343/112
`
`
`
`
`pering with the vehicle, and to a cellular antenna, and
`
`
`
`3,828,306 8/1974 Angeloni ............................... 340/32
`
`
`
`
`includes a controller for monitoring the sensor outputs
`
`
`
`
`3,848,254 11/1974 Drebinger et al. ................. 343/112
`
`
`
`
`and initiating an emergency message transmission to a
`
`
`3,886,553 5/1975 Bates ................................... 343/112
`
`
`
`remote monitoring station in the event of actuation of a
`3,922,678 11/1975
`
`
`Frenkel ............................... 343/112
`
`
`3,947,807 3/1976 Tyler et al. ........................... 340/23
`
`
`
`sensor. The car processing unit monitors site identifying
`
`
`
`
`3,997,868 12/1976 Ribnick et al. ........................ 340/33
`
`
`
`
`signals and signal strengths of transmissions from adja­
`
`
`
`4,101,873 7/1978 Anderson et al. .................. 340/539
`
`
`
`
`cent cellular transmitter sites in an emergency, and the
`
`
`
`4,112,421 9/1978 Freeny, Jr ........................... 343/112
`
`
`emergency message includes vehicle identifying infor­
`
`
`
`364/460 .................................. 4,139,889 2/1979 Ingels
`
`
`
`mation, cell site identifying information, and signal
`
`
`
`4,152,693 5/1979 Ashworth. Jr. ....................... 340/24
`
`
`
`strength information which will be dependent on dis­
`
`
`
`4,177,466 12/1979 Reagan ................................ 343/112
`
`
`340/65 4,187,497 2/1980 Howell et al. ........................
`
`
`
`tance from the cell site. The monitoring station includes
`
`
`
`4,209,787 6/1980 Freeny, Jr. .......................... 343/112
`
`
`
`a computer for determining and displaying an approxi­
`
`
`
`4,247,846 1/1981 Zedler ................................. 340/523
`
`
`
`mate vehicle location from the incoming cell site identi­
`
`
`340/32 4,369,426 1/1983 Merkel ..................................
`
`
`fying and signal strength information.
`
`
`
`
`4,475,010 10/1984 Huensch et al. ................. 179/2 EB
`
`
`
`4,494,119 1/1985 Wimbush .............................. 33/457
`
`
`
`340/539 et al. ...................... 4,577,182 3/1986 Millsap
`
`
`16 Claims, 7 Drawing Sheets
`
`19
`
`TELEPHONE
`COMPANY CO
`
`12
`
`Cisco v. TracBeam / CSCO-1010
`Page 1 of 14
`
`

`

`U.S. Patent June 8, 1993 Sheet 1 of 7 5,218,367
`
`J
`
`N
`
`Cisco v. TracBeam / CSCO-1010
`Page 2 of 14
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`

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`Cisco v. TracBeam / CSCO-1010
`Page 3 of 14
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`Cisco v. TracBeam / CSCO-1010
`Page 4 of 14
`
`

`

`U.S. Patent June 8, 1993 Sheet 4 of 7 5,218,367
`
`KEYBOARD
`77
`
`INPUT
`
`13
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`
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`
`7
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`
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`
`Cisco v. TracBeam / CSCO-1010
`Page 5 of 14
`
`

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`
`Cisco v. TracBeam / CSCO-1010
`Page 6 of 14
`
`

`

`U.S. Patent June 8, 1993
`
`5,218,367
`Sheet 6 of 7
`
`SECTORIZED
`CELL 2
`
`FIG. 7
`
`FIG.8
`
`Cisco v. TracBeam / CSCO-1010
`Page 7 of 14
`
`

`

`U.S. Patent June 8, 1993 Sheet 7 of 7 5,218,367
`
`m
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`
`Cisco v. TracBeam / CSCO-1010
`Page 8 of 14
`
`

`

`5,218,367
`
`1
`
`VEHICLE TRACKING SYSTEM
`
`2
`information lar transceiver for receiving cell identifying
`
`
`
`
`
`
`
`and signal strength information from all adjacent fixed
`
`
`cellular phone sites in the vicinity when an alarm se-
`BACKGROUND OF THE INVENTION
`
`
`
`quence is initiated, the controller being programmed to
`
`
`dial up a predetermined telephone number correspond­
`
`
`
`
`The present invention relates generally to vehicle
`S
`
`
`
`in the ing to the alarm monitoring station computer
`
`
`
`
`
`tracking and locating systems for locating vehicles in an
`
`event of an alarm and to transmit a packet of informa­
`emergency.
`
`
`
`tion to the computer via an adjacent cellular phone site,
`
`
`In U.S. Pat. Nos. 4,891,650 and 5,055,851 of Sheffer a
`
`
`
`
`vehicle locating system was described which relied on
`
`
`MTSO and central telephone office. The packet of
`
`the use of the existing nationwide cellular radio net-10
`
`
`
`information includes an alarm code, vehicle identifying
`
`work used in mobile telecommunications (cellular
`
`
`
`
`information, adjacent cell identifying information, and
`
`
`
`
`phone system). Cellular telephone networks rely on a
`
`
`
`
`
`the relative signal strengths of signals received by the
`
`
`fixed array of cell sites; each cell site covering a prede­
`
`
`
`
`transceiver from adjacent cells. The computer at the
`
`
`
`
`termined area and having a wireless signal detecting and
`
`
`
`alarm monitoring station is programmed to determine
`
`
`generating unit at a central location in the area. These IS
`
`
`
`
`the actual cell site locations from the incoming cell
`
`
`
`
`cell sites receive and transmit signals to and from cellu-
`
`
`
`identifying information, and to compute an approximate
`
`lar phones within their area on their own set of frequen­
`
`
`
`
`vehicle location from the cell relative signal strength
`
`cies, and are linked via conventional land lines to a
`information.
`
`
`mobile telecommunication switching office (MTSO) for
`Preferably, the computer is programmed to display a
`
`
`
`
`
`
`transmission to other cell sites, receivers, or conven-20
`
`
`
`
`
`map of the active cells region on a suitable display mon­
`
`
`
`tional phones via a telephone company central office
`
`
`
`itor linked to the computer and to indicate the com­
`(CO).
`
`
`puted vehicle location on the map in the form of a blink­
`U.S. Pat. Nos. 4,891,650 and 5,055,851 describe a
`
`
`
`
`
`ing colored dot or the like. According to a preferred
`
`
`
`system for detecting an emergency in a vehicle, such as
`
`
`embodiment of the invention, the system also includes
`25
`
`
`
`forced entry, and using the existing cellular radio net-
`
`
`
`
`similar cellular processing units for installation in field
`
`
`
`work to transmit an alarm signal from the vehicle to
`
`
`
`response unit (FRU) vehicles to be dispatched to the
`
`
`
`adjacent cell sites. The mobile telephone switching or
`approximate
`
`
`
`vehicle location computed in the event of
`
`
`MTSO is modified in order to transmit a signal indicat­
`
`
`an emergency, and the computer is also programmed.to
`
`
`
`
`ing the signal strength of the received alarm signal to an
`
`
`
`
`compute the approximate locations of.these FRU vehi­
`30
`
`
`
`
`external, to telephone company, central alarm station.
`
`cles and display them on the map in the form of differ-
`
`
`
`
`The transmitted signal also includes vehicle identifying
`
`
`
`ent colored dots. The actual location of the FRU vehi­
`
`
`
`information. At the central alarm station, the approxi­
`
`
`
`cles can also be entered manually by the computer oper­
`
`
`
`mate vehicle position can be estimated based on the
`
`
`
`ator and compared to the computed locations in order
`
`
`
`
`relative strengths of the signal received from the vehi­
`
`
`cle at adjacent cell sites. A police car can then be dis-3S
`
`
`
`to indicate a correction factor to be applied to the com­
`
`
`
`
`
`
`patched towards the approximate vehicle location. The
`
`
`puted approximate location of the vehicle being sought,
`
`
`
`tracking vehicle turns on its own cellular car radio so
`
`
`
`allowing the position to be continuously corrected as
`
`
`
`
`that the tracking vehicle is itself tracked using the same
`
`the FRU vehicles home in on the target.
`
`
`
`technique. In this way, an operator in the central alarm
`The cellular processing unit installed in the vehicle is
`
`
`
`
`
`
`
`
`
`monitoring station can observe the relative position of 40
`
`
`
`
`preferably similar to a conventional cellular telephone
`
`
`
`
`the original vehicle and the tracking vehicle or vehicles.
`
`
`
`unit and includes all the circuitry necessary for opera­
`
`
`
`Since the exact position of the tracking vehicle is
`
`
`
`tion as a conventional cellular phone. However, the
`
`
`known, this can be used to provide the tracking vehicle
`
`
`circuitry is modified to enable the unit to monitor the
`
`
`with instructions for moving towards the target.
`
`
`
`sensors and prepare and send the alarm message if an
`
`
`
`
`One disadvantage of this previous vehicle location 4S
`
`
`
`a memory alarm condition is detected. The unit includes
`
`system is that it requires modification of the software at
`
`
`
`
`
`or monitoring unit connected to the alarm sensors, a
`
`the MTSO so that it will generate the required signal
`
`
`
`
`central controller, and the transceiver for receiving
`strength signals for transmission to the central monitor­
`
`
`
`
`
`
`
`
`incoming signals and for transmitting outgoing signals
`ing station. This would be a relatively complex and
`
`
`
`
`
`
`to a is preferably linked via the antenna. The controller
`
`expensive procedure.
`SO
`
`
`
`conventional cellular phone handset for normal cellular
`
`
`phone communications. The unit is connected via a
`SUMMARY OF THE INVENTION
`
`
`
`
`switching circuit to a power supply. Preferably, the unit
`
`
`
`
`It is an object of the present invention to provide a
`
`
`
`is normally powered by the standard vehicle battery,
`new and improved vehicle tracking system for locating
`
`
`
`
`
`
`but is also connected to a back-up battery for use in the
`and tracking vehicles in emergency situations. SS
`
`
`
`
`
`event that the vehicle battery power is too low. The
`
`
`
`
`According to the present invention, a vehicle track­
`
`
`
`
`switching circuit is arranged to connect the memory
`
`
`
`a cellular pro­ing system is provided which comprises
`
`unit to the power supply at all times, but connects
`the
`
`
`
`
`cessing unit for installation in a vehicle, a plurality of
`
`power supply to the remainder of the unit only while
`
`
`
`alarm sensors connected to the cellular unit, the sensors
`
`
`the ignition is on or when an alarm condition is de­
`
`
`
`
`
`including break-in sensors for detecting an ignition start 60
`
`
`
`tected. The memory unit is arranged to monitor the
`
`
`without the car key, towing or emergency panic switch,
`
`
`sensor outputs at all times and to connect the power
`
`
`
`at least one cellular antenna connected to the cellular
`
`
`supply to the remainder of the circuit if an alarm is
`
`
`processing unit, and_ a remote alarm monitoring station
`
`
`
`
`detected while the ignition is off. Thus, break-in of a
`
`
`
`
`including a computer connected to a central telephone
`
`
`
`parked vehicle will initiate an alarm sequence. The
`
`
`
`network. The cellular processing unit mounted in the 6S
`
`
`
`
`controller is programmed to operate alternatively either
`
`
`
`vehicle includes a controller for monitoring .the output
`
`
`
`as a standard cellular communication unit or to transmit
`
`
`
`of the sensors and initiating an alarm sequence in the
`
`
`
`alarm messages to a pre-programmed telephone num-
`
`
`event of actuation of any one of the sensors, and a cellu-
`
`Cisco v. TracBeam / CSCO-1010
`Page 9 of 14
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`

`

`5,218,367
`
`4
`3
`conventional telephone lines or microwave link 17
`
`
`
`ber, and will disable the cellular handset while an alarm
`
`
`
`
`
`through the MTSO station 18, CO 19 and to the central
`
`message is being transmitted.
`
`
`
`processing station 14, as will be explained in more detail
`
`
`This system allows a conventional cellular telephone
`below.
`
`
`
`network to be used as part of a vehicle tracking system
`
`
`
`in the event of an emergency, without any modification 5
`in a apparatus 10 for mounting The signal processing
`
`
`
`
`
`
`is illustrated in more detail in FIGS. 2 and 3.
`
`
`
`to the hardware or software of the existing cellular
`vehicle
`
`
`
`phone network being required. All that is necessary is to
`
`
`
`The apparatus includes a modified cellular or trans­
`
`
`
`ceiver phone-type unit 32 which is illustrated schemati­
`
`
`install the modified cellular processing units in all vehi­
`
`
`
`cles to be protected using this tracking system so that
`
`cally in FIG. 2 and in more detail in FIG. 3. Unit 32
`
`they can communicate with one or more alarm monitor-10
`
`
`includes modified cellular phone circuitry as well as
`
`
`ing stations in the event of an emergency, the monitor­
`
`
`
`
`built-in alarm signal generating circuitry and software
`
`
`for generating an alarm signal in the event of an emer­
`
`
`ing station computers being set up to track the vehicle
`
`
`
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`and dispatch emergency response or FRU vehicles to
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`at gency. A pair of cellular antennas 22, 23 are mounted
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`the computed vehicle location. The system will be rela­
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`different, hidden locations in the vehicle and linked to
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`tively inexpensive to set up and run, and will allow 15
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`unit 10, along with a series of alarm sensors 26, 28; 30 of
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`stolen vehicles to be found quickly and easily, providing
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`various types. For example, a sensor 28 may be pro-
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`a significant deterrent to theft. One of the sensors in the
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`vided to detect starting of the ignition without a key,
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`vehicle may be in the form of a panic button, for exam­
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`while another sensor 26 may be arranged to detect
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`in an alarm sequence ple, allowing the driver to initiate
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`towing. An emergency/panic switch 30 for actuation
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`the event of a medical emergency or attempted vehicle 20
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`by the vehicle driver may also be provided as one of the
`hijack.
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`alarm sensors. This may be provided as a push button on
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`the cellular phone handset 45. Any conventional type of
`BRIEF DESCRIPTION OF THE DRAWINGS
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`car break-in detector or sensor as used for actuating
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`The present invention will be better understood from
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`typical car alarms may be used in this system. The modi­
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`the following detailed description of a preferred em-25
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`fied cellular phone unit is similar to a standard cellular
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`phone unit and has all the necessary hardware and soft-
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`bodiment of the invention, taken in conjunction with
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`the accompanying drawings, in which like reference
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`ware for cellular phone communication purposes. How­
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`numerals refer to like parts, and in which:
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`ever, the hardware and software is modified to enable
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`FIG. 1 is a schematic block diagram of a vehicle
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`the unit to additionally operate as an alarm unit in an
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`tracking system according to a preferred embodiment
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`emergency situation.
`30
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`of the present invention;
`The vehicle unit includes the modified cellular trans­
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`processing unit FIG. 2 is a block diagram of a cellular
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`ceiver 32 which is linked to the antennas 22 and 23 for
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`for installation in a vehicle;
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`receiving incoming radio signals from the antennas and
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`FIG. 3 is a more detailed circuit diagram of the unit
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`transmitting alarm as well as standard cellular telephone
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`35 signals via the antennas. The various sensors are linked
`of FIG. 2;
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`
`FIG. 4 is a schematic block diagram of a central
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`to a memory unit 34 which is connected to central con­
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`monitoring station forming part of the system of FIG. 1;
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`troller 36. The unit is connected via switch unit 38 and
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`FIG. 5 is a schematic block diagram of the configura­
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`battery back-up charger 40 to both the car battery 42
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`tion and information flow in the central monitoring
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`and a back-up battery 44. Conventional cellular phone
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`station computer;
`40
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`handset 45 is· connected to the controller. Unit 10 is
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`in the vicin-FIG. 6 illustrates a vehicle unit location
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`small enough to be mounted in a concealed location in
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`ity of three fixed cell sites and graphically illustrates a
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`a vehicle for added security.
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`triangulation process for estimating the vehicle position;
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`between the The controller provides an interface
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`FIG. 7 graphically illustrates a sectoring computation
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`alarm sensors and the transceiver, and is illustrated in
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`for estimating vehicle position;
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`more detail in FIG. 3. As illustrated in FIG. 3, the
`45
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`FIG. 8 schematically illustrates cell sector border
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`controller includes a transmit/receive message format-
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`lines for three adjacent cells; and
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`ter 46 which has a series of inputs from AND gates 48.
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`FIG. 9 is a schematic illustration of a final stage in the
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`Each AND gate has one input connected directly to the
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`tracking process.
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`output of a respective one of the sensors, and another
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`50 input connected to the output of memory unit 34. The
`DESCRIPTION OF THE PREFERRED
`
`
`memory unit 34 comprises an OR gate 50 having inputs
`EMBODIMENT
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`connected to all of the sensor outputs and output con­
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`
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`A vehicle tracking system according to a preferred
`nected to the AND gates via "D" flip flop 52. The
`embodiment of the present invention is schematically
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`
`
`
`
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`controller is connected via modem 54 and handset con­
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`
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`illustrated in FIG. 1. The system basically comprises a 55
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`trol 56 to cellular phone handset 45, which may be of a
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`cellular signal processing unit 10 mounted in a vehicle
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`conventional type or may be modified to provide a
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`12 and a central processing or monitoring station 14 for
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`"listen-in" feature in which emergency personnel can
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`receiving alarm signals emitted from the processing unit
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`listen to the noises or voices in the vehicle in the event
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`10 and computing an approximate vehicle position from
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`that the panic button is pressed. Some conventional
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`cellular phone handsets have a "hands free" option
`
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`those signals.• The system makes use of the existing· 60
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`nationwide cellular telephone system consisting of a
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`which enables a driver to use the phone without holding
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`plurality of radio transmitters or cell sites 16 each cov­
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`
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`the handset. This option consists of a built-in micro­
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`ering a predetermined cell area. The cell sites 16 cover­
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`phone and speaker. A handset having this option may
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`
`ing a predetermined region are linked to the MTSO 18
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`be used, or an extra speaker/microphone may be built in
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`and to the telephone company central office or CO 19, 65
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`to the vehicle, for example beneath the dashboard.
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`
`as will be understood by those skilled in the field. Alarm
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`A PROM memory unit 60 linked to controller con­
`
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`11 emitted from unit 10 are transmitted to the
`signals
`
`tains alarm information to be used in the event of an
`closest
`
`
`adjacent cell site 16 and relayed from there over
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`emergency, including a vehicle I.D. number, primary
`
`Cisco v. TracBeam / CSCO-1010
`Page 10 of 14
`
`

`

`5,218,367
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`6
`s ·
`vehicle identifying information, and the frequency
`
`and secondary emergency phone numbers to be con­
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`
`tacted in the event of an emergency, and other unit
`
`
`
`channel information sectoring information, and signal
`parameters.
`
`
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`strength information received from all the adjacent cell
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`
`
`When no alarm or emergency condition exists, the
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`
`sites. The data communications between the vehicle
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`
`
`unit 10 can be operated conventionally as a cellular 5
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`
`
`unit and the computer at the monitoring station use
`
`
`conventional modem to modem communication with a
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`phone. The controller and modified cellular transceiver
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`
`
`cellular phone are similar to those used in conventional
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`reliable communication protocol.
`
`
`units but are modified in order to respond to emergency
`The vehicle unit 10 is powered by the car battery 42
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`with the back-up battery 44 providing fall-back power
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`indications from any of the sensors to generate and
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`transmit an alarm signal to a predetermined telephone 10
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`should the car battery be out of commission. The mem­
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`number to which the computer at the monitoring sta­
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`ory circuit 34 is the only part of the unit which is contin­
`
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`uously powered up, even when the car ignition is off, as
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`
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`tion is connected. The controller provides an exclusive
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`
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`OR condition between the cellular handset and the
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`monitors continuously indicated in FIG. 2. This circuit
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`alarm signal transmission feature. Only one of these
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`the sensors for an alarm output, and triggers the switch­
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`options can be used at a time. Thus, when an emergency
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`ing box and consequently the rest of the circuit to be­
`15
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`situation is detected, the cellular handset enters a state
`
`come operational in the event of an alarm detection.
`Since this part of the unit will draw power even when
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`where it is. deactivated while the alarm signal is trans­
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`the car is stationary and the car battery 42 is not being
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`mitted, to ensure that voice input will not interfere with
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`recharged, it must draw extremely low current. As
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`the alarm transmission. However, the voice channel is
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`
`illustrated in FIG. 3, when any of the sensors is actu­
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`shared between the on-going alarm data transmission
`20
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`ated, the output of OR gate SO will be positive, operat­
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`and the voice signal. (In case of emergency /panic the
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`
`with moni­driver would need to stay in voice contact
`
`ing the flip-flop device to close the switch 51 in unit 38
`
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`and connect the remainder of the circuit to the power
`
`
`toring alarm station, even though the alarm data is con­
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`tinuously transmitted.) Once the alarm status is con­
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`supply. Additionally, switching box 38 will be on when-.
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`cluded, memory module 34 is deactivated and the cellu-25
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`ever the ignition is on and the cellular phone is on.
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`The central monitoring station will now be described
`
`
`Jar handset can be used for voice signal transmission
`only.
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`in more detail with reference to FIGS. 4-8. The station
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`includes a computer 70 connected via modem 72 to the .
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`In a conventional cellular telephone network, all cell
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`sites continuously transmit identifying signals 62 (see
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`telephone line 73. The· computer 70 has a memory 74
`
`
`FIG. 1) containing information on the cell I.D., the 30
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`which includes stored information on customers and
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`vehicle i.d. numbers, as well as cell site information
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`control channel frequency, and the voice channel fre­
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`quency and signal strength measurements of cell sites as
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`including cell frequency and sectoring information and
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`respective metro areas digital maps, or any other maps
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`sensed by a vehicle cellular phone. These signals can be
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`replicating the true nature of roads, landmarks and
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`picked up by mobile cellular phone units in the vicinity,
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`other significant items. The computer is linked to a
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`so that a currently "active" cell is used for transmitting
`35
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`suitable output video monitor 76, which preferably
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`signals to and from the vehicle. In the modified cellular
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`unit 10 of this invention, the transceiver is programmed
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`includes a standard display as well as a digital map
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`to scan all control and voice channels of the adjacent
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`display, and has operator input via keypad unit 77. The
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`computer is suitably programmed to respond to incom­
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`cellular sites for their signal transmissions to obtain
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`ing alarm signals and accompanying information pack­
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`frequency channel identification, sectoring information, 40
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`and signal strength, whenever an emergency sensor is
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`ets by computing an approximate vehicle position, as
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`will be explained in more detail below with reference to
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`activated. The two antennas are hidden at different
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`locations in the vehicle, and the transceiver is pro­
`FIGS. 6-8.
`Additionally, in a preferred embodiment of the inven­
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`grammed to take signal strength readings alternately
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`
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`tion, the computer operator is able to listen to the
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`from the two antennas. These readings are stored and 45
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`subsequently compared, and the highest value readings
`
`
`sounds inside the vehicle once the alarm has been acti­
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`are selected for transmission.
`
`
`vated, and may also talk to the vehicle occupants, if
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`
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`desired, via the speaker/microphone installed in the
`
`
`In the event that one of the sensors is activated, the
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`
`
`cellular phone handset or elsewhere in the vehicle
`
`
`
`controller determines which sensor the signal is re­
`
`
`ceived from, and obtains an alarm code corresponding 50
`
`
`which is automatically activated on detection of an
`
`
`
`alarm condition and receipt of a command signal from
`to this sensor from memory 60. At the same time, the
`
`
`the monitoring station. As noted above, the cellular
`
`
`in-built modem or DTMF transmitter 54 automatically
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`
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`goes "Off-Hook" and the transceiver commences scan­
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`
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`handset is deactivated while the alarm information is
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`
`
`
`ning all adjacent cellular sites, for their signal strength
`
`
`being transmitted. If the operator at the remote moni­
`
`
`
`toring station now dials the phone number of that cellu­
`
`
`
`
`readings, selecting the highest value readings from 55
`
`
`lar phone unit, they will be able to listen to the voices in
`
`
`readings from the two antennas. At this time, the con­
`
`
`the vehicle and also talk to the vehicle's occupants if
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`
`
`
`troller initiates a dialing sequence to the appropriate
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`
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`desired. This feature is particularly useful where the
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`telephone number, per the numbers stored in memory
`
`
`
`
`driver of the vehicle has activated a manually operated
`
`
`60, to link up with the computer at the central monitor­
`
`
`panic button on the cellular phone handset or on front
`
`
`
`ing station. In conjunction with the controller, the 60
`
`
`
`panel of the vehicle, for example. The operator can
`
`
`
`transceiver transmits an alarm message or packet of
`determine
`
`
`what type of emergency has occurred and
`
`
`
`information to the central computer. This packet is
`
`
`
`
`can dispatch the appropriate emergency response vehi­
`
`
`
`
`continuously updated and transmitted at periodic inter­
`vals to the telephone number as long as the alarm condi­
`
`cle.
`FIG. S illustrates the schematic configuration and
`
`
`
`
`
`
`
`tion exists. The telephone number dialed automatically 65
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`
`
`information flow in computer 70 on receipt of an incom­
`
`
`
`corresponds to the computer installed at the central
`
`
`ing information packet 79 from a vehicle unit in which
`
`
`
`monitoring station. The packet of information will in­
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`
`
`an emergency situation has occurred and been detected.
`
`clude the type of alarm code, the vehicle i.d., other
`
`Cisco v. TracBeam / CSCO-1010
`Page 11 of 14
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`

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`5,218,367
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`8
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`7
`All incoming alarm signals are first displayed on the
`
`
`
`
`
`monitor 76 and stored in a buffer memory area 83 in the
`
`
`computer. If more than one alarm is present, the opera­
`
`
`
`tor selects the alarm having the highest priority for
`5
`
`
`
`
`
`processing. The computer includes several databases 80,
`where r is the circle radius, SS is the signal strength, and
`
`
`
`
`
`81, 82 containing information on customers, cell site
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`
`
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`K is a constant. Based on this relationship, all r's can be
`
`
`locations, and cell sector information, respectively.
`
`
`expressed in terms of r1 . ri is first assumed to be small,
`
`
`
`When an incoming information packet is received, the
`
`and is then incremented until all the r's meet, at which
`
`
`
`information is synchronized (84) and customer database
`
`
`
`point the calculation is stopped. At this point, A will be
`10
`
`
`80 is searched based on the vehicle i.d. The cell site and
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`
`
`at its smallest value. The same technique can be used for
`
`
`
`
`sector. information databases are searched to determine
`
`any number of cell sites, or r's.
`
`
`
`the adjacent cell locations from the incoming cell infor­
`
`
`Since this procedure only provides an approximate
`
`
`
`
`mation. The cell and active cell sector determined from
`
`
`
`vehicle location, the position is further refined using
`
`
`the database are input along with the signal strength 15
`
`
`
`
`sectoring information, as illustrated in FIG. 7. Trans­
`
`
`levels to a temporary input buffer memory 83, and then
`
`
`mitted data from the vehicle unit includes identification
`
`
`
`the information is processed at 85 in accordance to
`
`
`
`of the voice frequency channel of each detected cell
`
`
`
`stored program instructions to determine the vehicle
`
`
`
`
`site, and the actual cell sites can therefore be determined
`
`
`
`location as a longitude and latitude. The approximate
`
`
`
`from the information stored in the computer's memory.
`20
`
`
`
`Each cell site is divided into sectors, as illustrated in
`
`
`
`
`vehicle location is transmitted via output buffer 86 to a
`
`
`
`FIG. 7, and each sector has an antenna pattern overlap­
`digital map display 87 on output screen 76. The com­
`
`
`
`
`
`
`ping the antenna patterns of adjacent sectors. The infor­
`
`
`puter also includes a field response unit FRU database
`
`
`mation transmitted from the vehicle will also include
`
`
`
`88 for storing identifying information on FRU vehicles
`
`
`
`the sector inform