System and method to locate radiomobiles outside the coverage of a cellular network

• US 20020183073A1
• Filed: 04/26/2002
• Published: 12/05/2002
• Est. Priority Date: 04/27/2001
• Status: Active Grant

• Current Assignee: Thales SA
• Original Assignee: Thales SA
• Inventors: Morgand, Philippe, Monot, Jean-Jacques
• Granted Patent: US 7,398,086 B2
• Time in Patent Office: Days
• US Class Current: 455/456.1
• CPC Class Codes: G01S 2205/006 for emergency situations
• CPC Class Codes: G01S 2205/008 using a mobile telephone network
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

Method for detection of one or more mobiles using a search device located at a certain altitude above the mobile comprising at least a cellular network simulation step to activate one or more mobiles on standby within range of the signals from the simulated signals and wherein it determines at least a parameter representative of one or more signals transmitted by the activated mobile(s).

Claims

1. - Method for detection of one or more mobiles using a search device located at a certain altitude above the mobile wherein it comprises at least a cellular network simulation step to activate one or more mobiles on standby within range of the signals issued from the simulation step and wherein it determines at least a parameter representative of one or more signals transmitted by the activated mobile(s).

2. - Method according to claim 1, wherein the network simulator is used to activate mobiles located outside the network or at the limit of the network.

3. - Method according to claim 1, wherein it uses an emergency frequency at the limit of the network.

4. - Method according to one of claims 1 to 3, wherein it deter mines an angular direction of the signals transmitted by the mobile(s), such as the angle of elevation and/or the azimuth angle.

5. - Method according to one of claims 1 to 4, wherein the simulator is adapted to a GSM or UMTS cellular network.

6. - Method according to claim 5, wherein the BSS modifies the parameters of the broadcast channel of the simulated network to force the mobile to repeat the location updating procedures by simulating a change of cell.

7. - Method according to claim 5 or 6, wherein the detection and goniometry are carried out on S_GSM type signals:

RACH, SDCCH and FACCH or S_UMTS type;

PRACH, DPPCH exchanged between the mobile and the network simulator.

8. - Method according to one of claims 4 to 7, wherein it comprises a measurement of the distance between the activated mobile and the network simulator, the distance measurement being associated with the measurement of angular direction to determine the position of the mobile(s) on standby.

9. - Method according to one of claims 1 to 8, wherein it uses a flat plate or trihedric antenna equipped with N radioelectric sensors to detect the transmissions from the mobiles.

10. - Method according to claim 9, wherein it comprises a step to tare the antenna'"'"'s reception channels, with a frequency generator positioned as close as possible to the antenna and used for self-calibration of the reception system up to the signal digitization.

11. - Application of the method according to one of claims 1 to 10 to the location in three dimensions of a person in difficulty equipped with a radiomobile in standby mode or a mobile telephone.

13. - System according to claim 12, wherein the simulator is adapted to a GSM network or to a UMTS network.

14. - System according to claim 13, wherein it is adapted to carry out detection and goniometry of S_GSM type signals:

RACH, SDCCH and FACCH or S_UMTS type;

PRACH, DPPCH exchanged between the mobile and the network simulator.

12. - System for detection and/or location of one or more mobiles at the limit of or outside a cellular communication network, wherein it comprises at least:

a device adapted to simulate a cellular communication network, in order to activate one or more mobiles on standby within range of the simulated signals,

a device to detect the signals exchanged between a mobile and the network simulator,

a signal processing device.

15. - System according to one of claims 12 to 14, wherein it uses a flat plate or trihedric antenna equipped with N radioelectric sensors to detect the transmissions from the mobiles.