WO2000014564A2 - Localisation d'un dispositif d'abonne mobile a l'aide d'un systeme a deux satellites - Google Patents

Localisation d'un dispositif d'abonne mobile a l'aide d'un systeme a deux satellites Download PDF

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Publication number
WO2000014564A2
WO2000014564A2 PCT/US1999/020255 US9920255W WO0014564A2 WO 2000014564 A2 WO2000014564 A2 WO 2000014564A2 US 9920255 W US9920255 W US 9920255W WO 0014564 A2 WO0014564 A2 WO 0014564A2
Authority
WO
WIPO (PCT)
Prior art keywords
subscriber device
movable subscriber
satellite
movable
estimate
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.)
Ceased
Application number
PCT/US1999/020255
Other languages
English (en)
Other versions
WO2000014564A3 (fr
Inventor
Thomas Peter Emmons, Jr.
Robert Anthony Peters
Mike Dane Ince
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Motorola Solutions Inc
Original Assignee
Motorola Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Motorola Inc filed Critical Motorola Inc
Priority to AU59079/99A priority Critical patent/AU5907999A/en
Publication of WO2000014564A2 publication Critical patent/WO2000014564A2/fr
Publication of WO2000014564A3 publication Critical patent/WO2000014564A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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
    • G01S1/022—Means for monitoring or calibrating
    • G01S1/026—Means for monitoring or calibrating of associated receivers
    • 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
    • G01S5/0246—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 involving frequency difference of arrival or Doppler 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
    • G01S5/01—Determining conditions which influence positioning, e.g. radio environment, state of motion or energy consumption
    • G01S5/019—Energy consumption
    • 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
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/15—Active relay systems
    • H04B7/185—Space-based or airborne stations; Stations for satellite systems
    • H04B7/1853—Satellite systems for providing telephony service to a mobile station, i.e. mobile satellite service
    • H04B7/18545—Arrangements for managing station mobility, i.e. for station registration or localisation
    • H04B7/18547—Arrangements for managing station mobility, i.e. for station registration or localisation for geolocalisation of a station
    • H04B7/1855—Arrangements for managing station mobility, i.e. for station registration or localisation for geolocalisation of a station using a telephonic control signal, e.g. propagation delay variation, Doppler frequency variation, power variation, beam identification
    • 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
    • G01S2205/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
    • G01S2205/001—Transmission of position information to remote stations
    • G01S2205/007—Transmission of position information to remote stations for management of a communication system
    • 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
    • G01S2205/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
    • G01S2205/001—Transmission of position information to remote stations
    • G01S2205/008—Transmission of position information to remote stations using a mobile telephone network
    • 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
    • G01S5/0009—Transmission of position information to remote stations
    • G01S5/0018—Transmission from mobile station to base station
    • G01S5/0027—Transmission from mobile station to base station of actual mobile position, i.e. position determined on mobile

Definitions

  • the invention relates to satellite communications and, more particularly, to techniques for locating a movable subscriber device at or near the surface of the earth.
  • an orbiting satellite In a satellite communication system, where orbiting satellites provide communication services to earth-based subscribers, it is particularly important to be able to determine the location of the subscriber. Consequently, in order to provide relatively efficient and low-cost communication services, an orbiting satellite must accurately locate earth-based subscribers. This allows the satellite to radiate signals to only those areas occupied by earth-based subscribers. Accurate location of subscribers also allows the satellite to generate receive beams from the particular direction occupied by a subscriber and avoid in-band interfering signals from those areas where subscribers do not exist. As satellite communication systems transmit and receive increasing amounts of information to and from earth-based subscribers, transmit and receive antenna beams must become correspondingly more narrow.
  • the need for narrow transmit and receive antenna beams stems from the increased gain requirements which transmit and receive antenna beams must possess in order to convey larger amounts of data per unit time to and from earth-based subscribers. Additionally, transmissions to earth-based subscribers must penetrate difficult environments such as forested areas or other locations where significant propagation loss can occur. Thus, the locations of earth-based subscribers must be known with greater accuracy as these transmit antenna beams become progressively more narrow.
  • Conventional methods for geolocation of movable subscriber devices such as pagers, cellular telephones, and other devices which receive messages from orbiting satellites, do not provide sufficient accuracy for advanced spacecraft in determining the area in which a particular movable subscriber device is located. Additionally, as more sophisticated geolocation methods are employed, more sophisticated movable subscriber devices are required.
  • the movable subscriber device must be capable of receiving information from an orbiting satellite at all times.
  • the movable subscriber device must be powered ON for a substantial period of time in order to receive geolocation, paging, and other information beams from the orbiting satellite. This places a strain on the power requirements of the movable subscriber device.
  • the resulting battery or other charge storage element within the movable subscriber device must then be larger or more often recharged. Both of these are undesirable to the user of the movable subscriber device.
  • FIG. 1 illustrates an orbiting satellite moving in relation to the earth's surface in accordance with a preferred embodiment of the invention
  • FIG. 2 illustrates an angle which represents a beam scan angle measured from the nadir of the satellite in the fore and aft directions in accordance with a preferred embodiment of the invention
  • FIG. 3 illustrates a Doppler frequency shift as a function of the angle ⁇ shown FIG. 2 in accordance with a preferred embodiment of the invention
  • FIG. 4 illustrates a second derivative of a Doppler frequency with respect to angle ⁇ of FIG. 3 in accordance with a preferred embodiment of the invention
  • FIG. 5 illustrates an angle ⁇ which represents a beam scan angle measured in a side-to-side dimension perpendicular to the direction of motion of an orbiting satellite in accordance with a preferred embodiment of the invention
  • FIG. 6 illustrates a change in time of arrival of information conveyed from an orbiting satellite with respect to angle ⁇ of FIG. 5 in accordance with a preferred embodiment of the invention
  • FIG. 7 illustrates a second orbiting satellite moving in relation to the earth's surface in accordance with a preferred embodiment of the invention
  • FIG. 8 illustrates a satellite transmit antenna beam sweep from a maximum scan angle, ® m , to a minimum scan angle in accordance with a preferred embodiment of the invention
  • FIG. 9 illustrates a method for geolocation of a movable subscriber device using dual satellites in accordance with a preferred embodiment of the invention
  • FIG. 10 illustrates a movable subscriber device in accordance with a preferred embodiment of the invention.
  • a method and apparatus for geolocation using dual satellites facilitates the accurate location of an earth-based movable subscriber device. This allows a satellite communication system to deliver messages to a particular area wherein a movable subscriber device is located using a narrow transmit antenna beam. Additionally this geolocation can be achieved with only a minimal increase in the complexity of the movable subscriber device.
  • FIG. 1 illustrates an orbiting satellite moving in relation to the earth's surface in accordance with a preferred embodiment of the invention.
  • satellite 10 transmits timing information to movable subscriber device 100, which is located at or near the surface of the earth.
  • Satellite 10 can be an orbiting communication satellite moving in a non-geostationary orbit.
  • satellite 10 can be another type of moving communications node which moves relative to earth-based movable subscriber device 100.
  • FIG. 1 illustrates a satellite
  • the present invention is not limited to the use of orbiting communication satellites but can include other moving communications nodes such as suitably equipped aircraft.
  • a transmit beam is radiated from the satellite's antenna.
  • this beam comprises geolocation information in the form of timing and frequency data and is transmitted to areas substantially directly beneath the satellite and to the sides of satellite 10.
  • the transmit beam is directed toward areas substantially perpendicular to the direction of motion of satellite 10, while the amount of energy radiated in front of or behind the satellite is minimal.
  • movable subscriber device 100 can obtain both Doppler frequency shift information as well as time of arrival information from the transmission from satellite 10. As will be discussed in reference to FIG. 4, this allows movable subscriber device 100 to locate itself on or near the surface of the earth with accuracy sufficient for many applications. Additionally, as is discussed in reference to FIG. 7, when a second satellite 20 is moving in an orbit which is nonparallel to the path of satellite 10, movable subscriber device 100 can locate itself on the surface of the earth with exceptional accuracy.
  • FIG. 2 illustrates an angle ⁇ which represents a beam scan angle measured from the nadir of the satellite in the fore and aft directions in accordance with a preferred embodiment of the invention.
  • Areas behind satellite 10 assume negative values of angle ⁇ , while areas in front of satellite 10 assume positive values of angle ⁇ .
  • Satellite 10 is assumed to be in motion relative to movable subscriber device 100.
  • FIG. 3 illustrates a Doppler frequency shift as a function of the angle ⁇ shown FIG. 2 in accordance with a preferred embodiment of the invention. As illustrated in FIG. 3, the larger positive and negative values of angle ⁇ correspond to those areas significantly in front of and behind satellite 10 of FIG. 1 , respectively.
  • Doppler frequency rate of change it is desirable to make use of Doppler frequency rate of change during those intervals when satellite 10 passes overhead or to the side of movable subscriber device 100.
  • Doppler frequency rate of change information such as a first or second derivative
  • movable subscriber device 100 is not required to possess extreme frequency accuracy in order to determine that satellite 10 has passed overhead or to the side of movable subscriber device 100.
  • this corresponds to a location on strip of constant Doppler frequency shift 50.
  • strip of constant Doppler frequency shift 50 reduces in width. For many paging applications, this provides sufficient geolocation for the efficient delivery of paging messages.
  • FIG. 4 illustrates a second derivative of a Doppler frequency with respect to angle ⁇ of FIG. 3 in accordance with a preferred embodiment of the invention.
  • the second derivative of a Doppler frequency shift when taken with respect to angle ⁇ , assumes a value of zero when angle ⁇ assumes a value of zero.
  • This technique is insensitive to frequency measurement errors inherent in any frequency generation or frequency measurement system.
  • the significance of FIG. 4 will be appreciated by those skilled in the art as providing an indication of Doppler frequency crossover without requiring precise frequency measurement by movable subscriber device 100. Movable subscriber device 100 can obtain a precise indication that satellite 10 has crossed strip of Doppler frequency shift 50 without requiring accurate Doppler signal frequency measurement by the movable subscriber device.
  • FIG. 5 illustrates an angle ⁇ which represents a beam scan angle measured in a side-to-side dimension perpendicular to the direction of motion of an orbiting satellite in accordance with a preferred embodiment of the invention.
  • Satellite 10 of FIG. 5 moves in a direction coming out of the page.
  • negative values of angle ⁇ denote directions to the left of satellite 10
  • positive values of angle ⁇ denote directions to the right of satellite 10.
  • FIG. 6 illustrates a change in time of arrival of information conveyed from an orbiting satellite with respect to angle ⁇ of FIG. 5 in accordance with a preferred embodiment of the invention.
  • DTOA delayed time of arrival
  • DTOA delayed time of arrival
  • a different signal should be broadcast by satellite 10.
  • the relative change in the delayed time of arrival can be assessed in order to determine whether the DTOA is increasing or decreasing. The ambiguity as to the polarity of angle ® can thus be removed.
  • FIG. 7 illustrates a second orbiting satellite moving in relation to the earth's surface in accordance with a preferred embodiment of the invention.
  • satellite 20 moves substantially perpendicular to the satellite of FIG. 1. Although shown and discussed as moving substantially perpendicular to satellite 10, this is only intended to facilitate an understanding of the present invention and is not intended to be limiting. The only requirement on the orbital path of satellite 20 is that the orbital path be nonparallel to that of satellite 10.
  • geolocation information similar to that transmitted by satellite 10 of FIG. 1 is radiated from satellite 20.
  • This second transmission of geolocation information allows movable subscriber device 100 to locate itself in an area along strip of constant Doppler frequency shift 51. Additionally, as is the case for the moving satellite 10 of FIG. 1 , movable subscriber device 100 can make use of the time of arrival information to further identify the location of movable subscriber device 100.
  • DTOA information is not required in order to locate movable subscriber device 100.
  • satellite 20 moves in an orbit that is not substantially perpendicular to that of satellite 10.
  • strips of constant Doppler frequency shift 50 and 51 intersect at other than right angles.
  • the area of intersection between strips of constant Doppler frequency shift encompass more area on the surface of the earth 30.
  • the second transmission of geolocation information from satellite 20 provides no significant capability for movable subscriber device 100 to refine its location since the strips of constant Doppler frequency shift 50 and 51 will not intersect.
  • FIG. 8 illustrates a satellite transmit antenna beam sweep from a maximum scan angle, ® m , to a minimum scan angle in accordance with a preferred embodiment of the invention.
  • satellite 10 positions an antenna and transmits the geolocation information beam beginning at an outer scan angle ⁇ m .
  • geolocation beam 70 is scanned in a manner such that geolocation information is received at movable subscriber devices 101 and 102 which are at or near the earth's surface at substantially the same time.
  • timing information from satellite 10 enables movable subscriber devices 101 and 102 to use DTOA from the satellite as discussed in relation to FIG. 6 as an indication of position.
  • timing information from satellite 10 is used to update the internal clocks of movable subscriber devices 101 and 102. Therefore, when satellite 10 transmits a second timing signal, movable subscriber devices 101 and 102 can use DTOA to determine distance from satellite 10.
  • This equation specifies the amount of precorrection which satellite 10 desirably applies to the timing information transmitted from the satellite to a plurality of movable subscriber devices, such as 101 and 102.
  • a correspondingly larger amount of precorrection is applied.
  • the amount of precorrection is approximately equal to 4.95 microseconds.
  • FIG. 9 illustrates a method for geolocation of a movable subscriber device using dual satellites in accordance with a preferred embodiment of the invention.
  • a movable subscriber device is activated and placed in a receive state. This activation can be the result of a timer or other control element determining that a satellite is expected to pass within range of the movable subscriber device. Desirably, a satellite passes within communications range of the movable subscriber device approximately every 10 minutes according to the ephemeris of the satellite; however, more or less frequent satellite passes may occur according to the orbits chosen for a particular application.
  • a satellite communications node transmits a geolocation information signal to a movable subscriber device.
  • step 220 is executed.
  • the movable subscriber device remains in an activated state until a geolocation information signal is received.
  • the movable subscriber device can develop an estimate of its current location, as in step 240.
  • the movable subscriber device makes an estimate of its location through the use of Doppler frequency shift and a derivative, or using time of arrival information.
  • the movable subscriber device estimates its location relative to the path of a first satellite communications node.
  • the movable subscriber device registers a new position through a transmission to the orbiting satellite, as in step 250.
  • the movable subscriber device may optionally wait for the second transmission before reregistering to provide increased accuracy. For this case, step 250 is not executed.
  • step 260 After completing the calculation of a new position, as in step 240, and optional registration, as in step 250, the movable subscriber device then executes step 260 which includes waiting for a second geolocation information signal.
  • the movable subscriber device executes step 280, where it refines the previous estimate of its current location.
  • step 290 a registration is performed by transmitting the current location to the satellite communications node. The device then returns to a sleep mode, as in step 300, and the process returns to step 200.
  • Step 300 is then executed, where the device returns to a sleep mode. The process then returns to step 200.
  • FIG. 10 illustrates a movable subscriber device in accordance with a preferred embodiment of the invention.
  • signals are received through antenna 110 and conveyed to receiver 120.
  • Receiver 120 functions to convert signals received from first and second moving communications nodes through antenna 110 to baseband. These baseband signals are then interpreted through processor 130.
  • Subscriber data such as text or other information, is presented to the user through display 170.
  • Signaling data such as geolocation and timing information, is used by processor 130 to develop an estimate of its location. This signaling data can comprise Doppler frequency and timing information signals.
  • Processor 130 is coupled to memory 140, which stores a past estimate of the location of the movable subscriber unit. In a preferred embodiment, these estimates are in the form of indications that either a first or second moving communications node has passed overhead.
  • Movable subscriber device 100 also comprises timer 160, which functions to alert processor 130 and receiver 120 that a predetermined interval of time has elapsed. In a preferred embodiment, this predetermined interval is determined in accordance with the ephemeris for the satellite constellation.
  • processor 130 determines that movable subscriber device 100 has changed locations
  • acknowledge messages are generated and transmitted through transmitter 150 and antenna 110.
  • a method and apparatus for geolocation using dual satellites facilitates the accurate location of an earth-based movable subscriber device. This function is performed by the movable subscriber device without requiring the movable subscriber device to maintain accurate timing or frequency references. Additionally, the receive function of the movable subscriber device does not need to be activated at all times. The resulting system provides guaranteed delivery of messages from the orbiting communication satellite while minimizing costs to subscribers.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Astronomy & Astrophysics (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Signal Processing (AREA)
  • Radio Relay Systems (AREA)
  • Position Fixing By Use Of Radio Waves (AREA)

Abstract

Cette invention permet de localiser avec précision un dispositif d'abonné mobile (100) dans un système de communication, dans lequel deux satellites en orbite (10, 20) se déplacent selon des trajectoires non parallèles. Chaque satellite transmet des informations de référence géographique qui sont reçues par le dispositif d'abonné mobile (100), lequel utilise ensuite des informations de changement de fréquence de Doppler ainsi que l'heure d'arrivée pour se localiser lui-même le long d'une première bande à la surface de la terre (30) qui s'étend perpendiculairement à la direction de déplacement du premier satellite (10). Lorsque les informations de référence géographique provenant du second satellite (20) sont reçues par le dispositif d'abonné mobile (100), celui-ci se localise lui-même le long d'une seconde bande à la surface de la terre (30) qui s'étend perpendiculairement à la direction de déplacement du second satellite (20). Le dispositif d'abonné mobile (100) peut alors être localisé avec précision à l'intersection de ces première et seconde bandes.
PCT/US1999/020255 1998-09-08 1999-09-02 Localisation d'un dispositif d'abonne mobile a l'aide d'un systeme a deux satellites Ceased WO2000014564A2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU59079/99A AU5907999A (en) 1998-09-08 1999-09-02 Movable subscriber device location using dual satellites

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US14906198A 1998-09-08 1998-09-08
US09/149,061 1998-09-08

Publications (2)

Publication Number Publication Date
WO2000014564A2 true WO2000014564A2 (fr) 2000-03-16
WO2000014564A3 WO2000014564A3 (fr) 2000-07-27

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PCT/US1999/020255 Ceased WO2000014564A2 (fr) 1998-09-08 1999-09-02 Localisation d'un dispositif d'abonne mobile a l'aide d'un systeme a deux satellites

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Country Link
AU (1) AU5907999A (fr)
WO (1) WO2000014564A2 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017156102A (ja) * 2016-02-29 2017-09-07 国立研究開発法人情報通信研究機構 位置推定システム
WO2023203730A1 (fr) * 2022-04-21 2023-10-26 日本電信電話株式会社 Procédé d'activation de dispositif de communication, système de communication sans fil et dispositif de communication sans fil

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2097974A1 (fr) * 1992-08-03 1994-02-04 Kristine P. Maine Determination de positions a distance
FR2721459B1 (fr) * 1994-06-21 1996-07-26 Alcatel Mobile Comm France Procédé de radiolocalisation d'un mobile à l'aide d'un satellite, dispositif de radiolocalisation, et procédé d'émission correspondants.
US5592175A (en) * 1995-08-25 1997-01-07 Motorola, Inc. Location determination method and apparatus for a communication unit
AU4643997A (en) * 1996-07-12 1998-02-09 Eagle Eye Technologies, Inc Method and apparatus for precision geolocation
US5844521A (en) * 1996-12-02 1998-12-01 Trw Inc. Geolocation method and apparatus for satellite based telecommunications system

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017156102A (ja) * 2016-02-29 2017-09-07 国立研究開発法人情報通信研究機構 位置推定システム
WO2017150323A1 (fr) * 2016-02-29 2017-09-08 国立研究開発法人情報通信研究機構 Système d'estimation d'emplacement
WO2023203730A1 (fr) * 2022-04-21 2023-10-26 日本電信電話株式会社 Procédé d'activation de dispositif de communication, système de communication sans fil et dispositif de communication sans fil
JPWO2023203730A1 (fr) * 2022-04-21 2023-10-26
JP7705083B2 (ja) 2022-04-21 2025-07-09 日本電信電話株式会社 通信装置の起動方法、無線通信システム及び無線通信装置

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Publication number Publication date
AU5907999A (en) 2000-03-27
WO2000014564A3 (fr) 2000-07-27

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