CA2171333A1 - Apparatus and method for locating cellular telephones and similar transmitters - Google Patents
Apparatus and method for locating cellular telephones and similar transmittersInfo
- Publication number
- CA2171333A1 CA2171333A1 CA002171333A CA2171333A CA2171333A1 CA 2171333 A1 CA2171333 A1 CA 2171333A1 CA 002171333 A CA002171333 A CA 002171333A CA 2171333 A CA2171333 A CA 2171333A CA 2171333 A1 CA2171333 A1 CA 2171333A1
- Authority
- CA
- Canada
- Prior art keywords
- transmitter
- phone
- portable receiver
- predetermined range
- determining
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S1/00—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith
- G01S1/02—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith using radio waves
- G01S1/08—Systems for determining direction or position line
- G01S1/20—Systems for determining direction or position line using a comparison of transit time of synchronised signals transmitted from non-directional antennas or antenna systems spaced apart, i.e. path-difference systems
- G01S1/24—Systems for determining direction or position line using a comparison of transit time of synchronised signals transmitted from non-directional antennas or antenna systems spaced apart, i.e. path-difference systems the synchronised signals being pulses or equivalent modulations on carrier waves and the transit times being compared by measuring the difference in arrival time of a significant part of the modulations, e.g. LORAN systems
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W64/00—Locating users or terminals or network equipment for network management purposes, e.g. mobility management
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
- G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
- G01S5/06—Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
- G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
- G01S5/12—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M11/00—Telephonic communication systems specially adapted for combination with other electrical systems
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
- G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
- G01S5/04—Position of source determined by a plurality of spaced direction-finders
Abstract
The field of locating cellular telephones suffers from high multipath city environments which affect accuracy. This problem can be overcome by a two tiered approach including a general location determination using cellular base station located system (10) and subsequent finite location using a portable receiver (26) capable of functioning in high multipath environments. Applications include emergency calls and criminal investigations.
Description
~ w096/02007 2 ~ 7 I 3 ~ 3 PCT~S95/08527 , APPARAT~S AND M~ FOR ~OCATING r~rrm-~ TE~h~N~S
AND SIMIr-AR TRANSh~ ~KS
S
Bac~lou.,d o~ the Invention Field of the Invention The present invention generally relates to the function of locating cellular telephones and other mobile transmitters, and particularly, to a method and apparatus which use a two stage approach including a long range, variable accuracy technique in combination with a short range, high accuracy technigue.
IS 8tatement of the Prior Art The proliferation of cellular telephones, or cell phones, and their technology and usage, has revealed various applications for the ability to locate cell phones and similar transmitters. These applications include ~911~ calls, tourist and travel information, the tracking of commercial, government and stole Yehicles, and the identification of unauthorized cell ~-~one usage and illegal activities, to name a few. The basic cell phone systems can only determine the nearest cell phone base station, which locates the cell pho~e to within 3 to 10 miles.
A goal of any such system for use with cellul~
phones is the use of as much existing eguipment as possible or at least compatibility with existing eguipment. Examples of this are use with unmodified cellular phones and compatibility with existing cellular base stations.
A great deal of technoloqy already exists concerning the tracking or locating of radio transmitters. One W096/02007 3 PCT~S~5/~85~.7 least in such applications as LORAN and GPS. The application of this process to cell phones includes accurately measuring the time of arrival of the same signal at a multiplicity of base stations and comparing 5 the times to determine the difference between transmission times to each base station. Tdoa techni~ues do not re~uire any modifications of the transmitters, because they operate on the ordinary signal transmitted.
Tdoa techni~ues are also compatible with existing 10 omnidirectional cell phone, base station antennas.
One such application of tdoa technology combined with direction finding and applied to cellular phones is described in US Patent No. 5,317,323. The system described therein uses GPS timing signals at the 15 receivers to determine the time of signal reception.
Direction f;n~;ng is used to reduce multipath and co-channel interference. Unfortunately, the use of direction finding requires the use of a steerable antenna or array and i8 thus not compatible with the existinq 20 omnidirectional antenna structures used in the cell phone industry. Even sectored antennas, which may be used for cell phones, do not provide sufficient accuracy. The patent does show the importance of ~-.~ving multipath interference. Thus, it is a goal of any such locating system for cellular telephones to distinguish between a direct signal from a cell phone and multipath reflections of the same signal from buildings and other reflectors.
Reflected signals, which take a longer and unknown path to the receiver, provide less accurate location 30 information.
A similar approach to locating cell ~hone~ is 6 described in US Patent No. 5,327,144. This approach employs tdoa techni~ues by collecting all data transmitted by cell rho~es on the rever~e control channel ~ w096/02007 21 71333 PCT~S~S/~8~27 and cross correlating that data to identify and locate those cell phones. This approach demonstrates an inherent deficit in using the tdoa techni~ue alone with unmodified cell phones in that the signal which is being S measured is limited to a 30 KHz transmission channel.
This limited bandwidth limits the accuracy of the tdoa measurement under ideal conditions to a theoretical 300 feet. Whenever any sort of multipath or co-channel interference is encountered, this accuracy deteriorates significantly.
S~MM~Y OF THE lN V~. .lON
Accordingly, it is a object of the present invention to provide an apparatus and method for determ; n; ng the location of cellular telephones and similar transmitters which provides a hi~h degree of accuracy.
It is a further object of the present invention to perform such location f;n~;ng on ordinary cell phones and similar transmitters which are not specially modified.
It is still a further object of the present invention to perform such location f;n~;ng in the presence of high levels of multipath reflected signals.
It is yet a further object of the present invention to perform such location f;n~; n~ using antennas and antenna structures which are normally used for typical cell phone operation.
In one embodiment, the present invention provides a method for determ;n;ng the location of a cellular telephone or similar transmitter, comprising the steps of 30 detPrm; n; ng the general location of the phone or transmitter within a predetermined range by receiving transmissions thereof at a plurality of locations and signal processing the received signals, receiving tr~ncmission signals from the phone or transmitter with a wo~ 0~7 2~333 PCT~595108527 ~
portable receiver located within the predetermined range of the phone or transmitter, and determ;ning the precise location of the cell phone or transmitter in response to the transmission signals received by the portable S receiver. ~, In another embodiment, the present invention provides an apparatus for determin;ng the location of a cell phone or similar transmitter, comprising means for determ; n; n~ the general location of the phone or transmitter within a predetermined range thereof including means for receiving transmissions therefrom at a plurality of locations and means for signal processing the received signals, and portable receiver means adapted for movement to within the predetermined range of the lS phone or transmitter for receiving tr~n~mi~sion signals from the phone or transmitter and including means for determining the precise location of the cell phone or transmitter in response to the received transmission signals.
BRIEF DESCRl, ~10~ OF THE DRAWIN~S
The present invention is illustratively described in reference to the appended drawings in which:
Fig. 1 is a system block diagram of an apparatus constructed in accordance with a portion of one embodiment of the present invention.
DETATr~r~!n DEgCR'CPTION OF ~HE DRAWING~g Fig. 1 shows one embodiment of a cell phone locating system 10 which would take advantage of existing cell phone base stations and antennas. System 10 generally includes a multiplicity of existing cellular ba~e stations 12-14, to which apparatus of the present invention is added. Base stations 12-14 make use of 21 713~3 existing transmit and receive antennas 16 which may be identical in form and function. Added to each base station is an additional GPS (Global Positioning System) antenna 18 which receives timing signals from the S existing civilian GPS for use in the locating function.
Each of the base stations includec further equipment for performing the locating function. This equipment generally includes means for sampling or digitizing the signals received from the cell phone or transmitter 22 and time stamping the resulting data with signals derived from the received GPS signal.
Com~l~nication lines 19 are shown connecting at least two remote base stations 12,13 with a central base station 14. Central base station 14 includes equipment lS not present in the remote base stations 12,13 in the form of tdoa CPU 20 for proce~cing signals received by all base stations 12-14. Tdoa CPU 20 may be located at any one of the base stations or m~y be located separately from such base stations. Such separate location would include the interconnection of all comm. lines 19 directly between the base stations and tdoa CPU 20.
Tdoa CPU 20 receives the digitized, time stamped data from each of the receiving base stations and cross correlates similar data. The time ~tamps on the correlated data thereupon provide time difference of arrival data between the correlated data and the correspondin~ base stations, which have known locations.
The general location of cell phone or transmitter 22 may then be determined in accordance with well known techniques.
The tdoa system described above provides a meAnc for det~nm; ni ng a general location of a cell phone or similar transmitter 22 within a predetermined range represented by circle 24. This general location function may be w096/02007 PCT~S95/08S27 provided by any other suitable technique such as direction finding. One acceptable tdoa method is described in US Patent Application Number 08/272,725 filed July 8, 1994 for APPARATUS AND METHOD FOR LOCATING
5 CELLULAR TELEPHONES by the same inventor hereof, the contents of which are hereby incorporated by reference herein.
Once the general location of circle 24 is known, a portable receiver 26 may be transported to that area and used for precisely locating the phone or transmitter 22.
Where a local police force carries the portable receiver in a number of patroling police cars, such a portable reciever may already be located within the general location of circle 24. The size of circle 24 technically lS depends upon the accuracy of the location e~uipment described above. However, it is much more practical if the size of circle 24 is ~ curate with the receiving capability of the portable receiver 24. Due to the limited elevation of the portable receiver 26, terrain will have an impact upon receiver performance.
The portable receiver 26 may also be of any suitable type and make. One such type is described in US Patent Application No. 08/272,724, Filed July 8, 1994 entitled APs?ARATUS AND sYETHOD FOR FINDING A SIGNAL EMISSION SOURCE
by David I.. Herrick and William F. Matthews III, the contents of which are hereby incorporated by reference herein. The portable receiver in ~Sestion u~es relative -lovc...e5lt between the receiver and the phone or transmitter 22 to determine the general direction thereof. The described techni~ue is useful in high multipath enviLol55--c5lts such as buildings. Other fors~s of direction finding may also be suitable.
In order for the portable receiver 26 to accurately locate the cell phone or transmitter 22, it will be WO 96/02007 l 333 PCTlUS9~i/08S~7 necessary to determine the transmitting frequency of the phone or transmitter 22 and receive that signal. In the case of a cellular phone 22, the transmission frequency will depend upon a channel allocation from the local cell S phone system. To determine the proper channel allocation it may be preferable to establi~h a co~un;cation link between receiver 26 and the local cellular system to receive the channel assignment.
The locating system thus provided overcomes any inaccuracies present in the long range system without requiring significant additional expen~e. Such inaccuracies may even be impossible to avoid in high multipath enviro~llel~ts. The addition expense of a high accuracy system located in cellular base stations is significant given the number of operating base stations.
The embodiments described above are intended to be taken in an illustrative and not a limiting sense.
Various modifications and changes may be made to the above embodiments by per~ons skilled in the art without departing from the scope of the present invention as defined in the appended claims.
AND SIMIr-AR TRANSh~ ~KS
S
Bac~lou.,d o~ the Invention Field of the Invention The present invention generally relates to the function of locating cellular telephones and other mobile transmitters, and particularly, to a method and apparatus which use a two stage approach including a long range, variable accuracy technique in combination with a short range, high accuracy technigue.
IS 8tatement of the Prior Art The proliferation of cellular telephones, or cell phones, and their technology and usage, has revealed various applications for the ability to locate cell phones and similar transmitters. These applications include ~911~ calls, tourist and travel information, the tracking of commercial, government and stole Yehicles, and the identification of unauthorized cell ~-~one usage and illegal activities, to name a few. The basic cell phone systems can only determine the nearest cell phone base station, which locates the cell pho~e to within 3 to 10 miles.
A goal of any such system for use with cellul~
phones is the use of as much existing eguipment as possible or at least compatibility with existing eguipment. Examples of this are use with unmodified cellular phones and compatibility with existing cellular base stations.
A great deal of technoloqy already exists concerning the tracking or locating of radio transmitters. One W096/02007 3 PCT~S~5/~85~.7 least in such applications as LORAN and GPS. The application of this process to cell phones includes accurately measuring the time of arrival of the same signal at a multiplicity of base stations and comparing 5 the times to determine the difference between transmission times to each base station. Tdoa techni~ues do not re~uire any modifications of the transmitters, because they operate on the ordinary signal transmitted.
Tdoa techni~ues are also compatible with existing 10 omnidirectional cell phone, base station antennas.
One such application of tdoa technology combined with direction finding and applied to cellular phones is described in US Patent No. 5,317,323. The system described therein uses GPS timing signals at the 15 receivers to determine the time of signal reception.
Direction f;n~;ng is used to reduce multipath and co-channel interference. Unfortunately, the use of direction finding requires the use of a steerable antenna or array and i8 thus not compatible with the existinq 20 omnidirectional antenna structures used in the cell phone industry. Even sectored antennas, which may be used for cell phones, do not provide sufficient accuracy. The patent does show the importance of ~-.~ving multipath interference. Thus, it is a goal of any such locating system for cellular telephones to distinguish between a direct signal from a cell phone and multipath reflections of the same signal from buildings and other reflectors.
Reflected signals, which take a longer and unknown path to the receiver, provide less accurate location 30 information.
A similar approach to locating cell ~hone~ is 6 described in US Patent No. 5,327,144. This approach employs tdoa techni~ues by collecting all data transmitted by cell rho~es on the rever~e control channel ~ w096/02007 21 71333 PCT~S~S/~8~27 and cross correlating that data to identify and locate those cell phones. This approach demonstrates an inherent deficit in using the tdoa techni~ue alone with unmodified cell phones in that the signal which is being S measured is limited to a 30 KHz transmission channel.
This limited bandwidth limits the accuracy of the tdoa measurement under ideal conditions to a theoretical 300 feet. Whenever any sort of multipath or co-channel interference is encountered, this accuracy deteriorates significantly.
S~MM~Y OF THE lN V~. .lON
Accordingly, it is a object of the present invention to provide an apparatus and method for determ; n; ng the location of cellular telephones and similar transmitters which provides a hi~h degree of accuracy.
It is a further object of the present invention to perform such location f;n~;ng on ordinary cell phones and similar transmitters which are not specially modified.
It is still a further object of the present invention to perform such location f;n~;ng in the presence of high levels of multipath reflected signals.
It is yet a further object of the present invention to perform such location f;n~; n~ using antennas and antenna structures which are normally used for typical cell phone operation.
In one embodiment, the present invention provides a method for determ;n;ng the location of a cellular telephone or similar transmitter, comprising the steps of 30 detPrm; n; ng the general location of the phone or transmitter within a predetermined range by receiving transmissions thereof at a plurality of locations and signal processing the received signals, receiving tr~ncmission signals from the phone or transmitter with a wo~ 0~7 2~333 PCT~595108527 ~
portable receiver located within the predetermined range of the phone or transmitter, and determ;ning the precise location of the cell phone or transmitter in response to the transmission signals received by the portable S receiver. ~, In another embodiment, the present invention provides an apparatus for determin;ng the location of a cell phone or similar transmitter, comprising means for determ; n; n~ the general location of the phone or transmitter within a predetermined range thereof including means for receiving transmissions therefrom at a plurality of locations and means for signal processing the received signals, and portable receiver means adapted for movement to within the predetermined range of the lS phone or transmitter for receiving tr~n~mi~sion signals from the phone or transmitter and including means for determining the precise location of the cell phone or transmitter in response to the received transmission signals.
BRIEF DESCRl, ~10~ OF THE DRAWIN~S
The present invention is illustratively described in reference to the appended drawings in which:
Fig. 1 is a system block diagram of an apparatus constructed in accordance with a portion of one embodiment of the present invention.
DETATr~r~!n DEgCR'CPTION OF ~HE DRAWING~g Fig. 1 shows one embodiment of a cell phone locating system 10 which would take advantage of existing cell phone base stations and antennas. System 10 generally includes a multiplicity of existing cellular ba~e stations 12-14, to which apparatus of the present invention is added. Base stations 12-14 make use of 21 713~3 existing transmit and receive antennas 16 which may be identical in form and function. Added to each base station is an additional GPS (Global Positioning System) antenna 18 which receives timing signals from the S existing civilian GPS for use in the locating function.
Each of the base stations includec further equipment for performing the locating function. This equipment generally includes means for sampling or digitizing the signals received from the cell phone or transmitter 22 and time stamping the resulting data with signals derived from the received GPS signal.
Com~l~nication lines 19 are shown connecting at least two remote base stations 12,13 with a central base station 14. Central base station 14 includes equipment lS not present in the remote base stations 12,13 in the form of tdoa CPU 20 for proce~cing signals received by all base stations 12-14. Tdoa CPU 20 may be located at any one of the base stations or m~y be located separately from such base stations. Such separate location would include the interconnection of all comm. lines 19 directly between the base stations and tdoa CPU 20.
Tdoa CPU 20 receives the digitized, time stamped data from each of the receiving base stations and cross correlates similar data. The time ~tamps on the correlated data thereupon provide time difference of arrival data between the correlated data and the correspondin~ base stations, which have known locations.
The general location of cell phone or transmitter 22 may then be determined in accordance with well known techniques.
The tdoa system described above provides a meAnc for det~nm; ni ng a general location of a cell phone or similar transmitter 22 within a predetermined range represented by circle 24. This general location function may be w096/02007 PCT~S95/08S27 provided by any other suitable technique such as direction finding. One acceptable tdoa method is described in US Patent Application Number 08/272,725 filed July 8, 1994 for APPARATUS AND METHOD FOR LOCATING
5 CELLULAR TELEPHONES by the same inventor hereof, the contents of which are hereby incorporated by reference herein.
Once the general location of circle 24 is known, a portable receiver 26 may be transported to that area and used for precisely locating the phone or transmitter 22.
Where a local police force carries the portable receiver in a number of patroling police cars, such a portable reciever may already be located within the general location of circle 24. The size of circle 24 technically lS depends upon the accuracy of the location e~uipment described above. However, it is much more practical if the size of circle 24 is ~ curate with the receiving capability of the portable receiver 24. Due to the limited elevation of the portable receiver 26, terrain will have an impact upon receiver performance.
The portable receiver 26 may also be of any suitable type and make. One such type is described in US Patent Application No. 08/272,724, Filed July 8, 1994 entitled APs?ARATUS AND sYETHOD FOR FINDING A SIGNAL EMISSION SOURCE
by David I.. Herrick and William F. Matthews III, the contents of which are hereby incorporated by reference herein. The portable receiver in ~Sestion u~es relative -lovc...e5lt between the receiver and the phone or transmitter 22 to determine the general direction thereof. The described techni~ue is useful in high multipath enviLol55--c5lts such as buildings. Other fors~s of direction finding may also be suitable.
In order for the portable receiver 26 to accurately locate the cell phone or transmitter 22, it will be WO 96/02007 l 333 PCTlUS9~i/08S~7 necessary to determine the transmitting frequency of the phone or transmitter 22 and receive that signal. In the case of a cellular phone 22, the transmission frequency will depend upon a channel allocation from the local cell S phone system. To determine the proper channel allocation it may be preferable to establi~h a co~un;cation link between receiver 26 and the local cellular system to receive the channel assignment.
The locating system thus provided overcomes any inaccuracies present in the long range system without requiring significant additional expen~e. Such inaccuracies may even be impossible to avoid in high multipath enviro~llel~ts. The addition expense of a high accuracy system located in cellular base stations is significant given the number of operating base stations.
The embodiments described above are intended to be taken in an illustrative and not a limiting sense.
Various modifications and changes may be made to the above embodiments by per~ons skilled in the art without departing from the scope of the present invention as defined in the appended claims.
Claims (11)
1. A method for determining the location of a cellular telephone or similar transmitter, comprising the steps of:
determining the general location of the phone or transmitter within a predetermined range by receiving transmissions thereof at a plurality of locations and signal processing the received signals;
receiving transmission signals from the phone or transmitter with a portable receiver located within the predetermined range of the phone or transmitter; and determining the precise location of the cell phone or transmitter in response to the transmission signals received by the portable receiver.
determining the general location of the phone or transmitter within a predetermined range by receiving transmissions thereof at a plurality of locations and signal processing the received signals;
receiving transmission signals from the phone or transmitter with a portable receiver located within the predetermined range of the phone or transmitter; and determining the precise location of the cell phone or transmitter in response to the transmission signals received by the portable receiver.
2. The method of claim 1, wherein the plurality of locations of transmission reception are base stations of a cellular telephone network.
3. The method of claim 2, wherein the predetermined range is determined by the reception capabilities of the portable receiver.
4. The method of claim 3, wherein the step of determining the general location is accomplished using time difference of arrival signal processing techniques.
5. The method of claim 1, further comprising the step of transporting the portable receiver to within the predetermined range of the phone or transmitter to be located.
6. The method of claim 1, wherein the step of determining the precise location includes measuring a characteristic of the transmission signal received within the predetermined range while moving the portable receiver and moving the portable receiver in response to the measured characteristic.
7. An apparatus for determining the location of a cell phone or similar transmitter, comprising:
means for determining the general location of the phone or transmitter within a predetermined range thereof including means for receiving transmissions therefrom at a plurality of locations and means for signal processing the received signals; and portable receiver means adapted for movement to within the predetermined range of the phone or transmitter for receiving transmission signals from the phone or transmitter and including means for determining the precise location of the cell phone or transmitter in response to the received transmission signals.
means for determining the general location of the phone or transmitter within a predetermined range thereof including means for receiving transmissions therefrom at a plurality of locations and means for signal processing the received signals; and portable receiver means adapted for movement to within the predetermined range of the phone or transmitter for receiving transmission signals from the phone or transmitter and including means for determining the precise location of the cell phone or transmitter in response to the received transmission signals.
8. The apparatus of claim 7, wherein the plurality of locations of transmission reception are base stations of a cellular telephone network.
9. The apparatus of claim 8, wherein the predetermined range is determined by the reception capabilities of the portable receiver.
10. The apparatus of claim 9, wherein the means for signal processing includes a time difference of arrival algorithm.
11. The apparatus of claim 7, wherein the portable receiver means includes means for measuring a characteristic of the received signal during movement of the receiver means for providing an indication of the direction of the precise location.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/272,725 US5512908A (en) | 1994-07-08 | 1994-07-08 | Apparatus and method for locating cellular telephones |
| US08/272,725 | 1994-07-08 | ||
| US08/272,724 US5625364A (en) | 1994-07-08 | 1994-07-08 | Apparatus and method for finding a signal emission source |
| US08/272,724 | 1994-07-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2171333A1 true CA2171333A1 (en) | 1996-01-25 |
Family
ID=26955698
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002171333A Abandoned CA2171333A1 (en) | 1994-07-08 | 1995-07-07 | Apparatus and method for locating cellular telephones and similar transmitters |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0717852A1 (en) |
| KR (1) | KR960705222A (en) |
| AU (1) | AU2964695A (en) |
| CA (1) | CA2171333A1 (en) |
| NZ (1) | NZ289719A (en) |
| WO (1) | WO1996002007A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6741863B1 (en) | 1998-12-18 | 2004-05-25 | Lucent Technologies Inc. | Method and apparatus for locating a wireless mobile unit |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE513158C2 (en) * | 1999-03-31 | 2000-07-17 | Satsafe Mls Ab | Method and portable system for location of mobile phone |
| SE522597C2 (en) * | 2001-03-26 | 2004-02-24 | Telia Ab | Device and methods for positioning mobile communication devices |
| GB0117951D0 (en) * | 2001-07-24 | 2001-09-19 | Koninkl Philips Electronics Nv | Methods and apparatus for determining the position of a transmitter and mobile communitcations device |
| FI116996B (en) * | 2004-11-02 | 2006-04-28 | Nethawk Oyj | Procedure for positioning mobile equipment, mobile positioning system, base station and network elements |
| KR101039873B1 (en) | 2011-03-02 | 2011-06-09 | (주)한국전산감리원 | Electronic anklet notification system and electronic anklet notification method |
| RU2594759C1 (en) * | 2015-10-28 | 2016-08-20 | Федеральное государственное казенное военное образовательное учреждение высшего профессионального образования "ВОЕННАЯ АКАДЕМИЯ СВЯЗИ имени Маршала Советского Союза С.М. Буденного" Министерства обороны Российской Федерации | Method and device for determining coordinates of a radio emission |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5003317A (en) * | 1989-07-11 | 1991-03-26 | Mets, Inc. | Stolen vehicle recovery system |
| US5343493A (en) * | 1993-03-16 | 1994-08-30 | Hughes Aircraft Company | Personal assistance system and method for use with a cellular communication system |
| US5327144A (en) * | 1993-05-07 | 1994-07-05 | Associated Rt, Inc. | Cellular telephone location system |
-
1995
- 1995-07-07 AU AU29646/95A patent/AU2964695A/en not_active Abandoned
- 1995-07-07 WO PCT/US1995/008527 patent/WO1996002007A1/en not_active Application Discontinuation
- 1995-07-07 EP EP95925550A patent/EP0717852A1/en not_active Withdrawn
- 1995-07-07 CA CA002171333A patent/CA2171333A1/en not_active Abandoned
- 1995-07-07 KR KR1019960701286A patent/KR960705222A/en not_active Application Discontinuation
- 1995-07-07 NZ NZ289719A patent/NZ289719A/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6741863B1 (en) | 1998-12-18 | 2004-05-25 | Lucent Technologies Inc. | Method and apparatus for locating a wireless mobile unit |
Also Published As
| Publication number | Publication date |
|---|---|
| NZ289719A (en) | 1997-02-24 |
| AU2964695A (en) | 1996-02-09 |
| WO1996002007A1 (en) | 1996-01-25 |
| KR960705222A (en) | 1996-10-09 |
| EP0717852A1 (en) | 1996-06-26 |
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