METHOD FOR GEOLOCATING A RECEIVER

Abstract

A method for geolocating a receiver by measuring times of reception, by the receiver, of a plurality of geolocation signals originating from a plurality of emitters, the geolocation signals are emitted on multiple different wavelengths, at least one geolocation signal having a frequency less than 1 GHz.

Claims

1. A method for geolocating a receiver by measuring times of reception, by the receiver, of a plurality of geolocation signals originating from a plurality of emitters, the geolocation signals are emitted on multiple different wavelengths, at least one geolocation signal having a frequency less than 1 GHz.

2. The method according to claim 1, the receiver having a clock synchronized with the emitters, the method comprising the steps of: determining the propagation times of the geolocation signals from the emitters and to the receiver, computing the distances between the receiver and the emitters based on these propagation times, and determining the position of the receiver using a localization technique on the basis of the computed distances.

3. The method according to claim 1, the receiver not having a clock synchronized with the emitters, the method comprising the steps of: for at least three transmitters, determine, for at least one couple M1 and M2 of its transmitters, a slice delimited by two hyperbolic surfaces of revolution around the line linking the transmitters M1 and M2, the two hyperbolas are defined by the position of the emitters M1 and M2 and a difference in length of the points of the hyperbolas at the two positions of the emitters M1 and M2, determine the position of the receiver by intersection of said slice and a plane formed by the three transmitters.

4. The method according to claim 1, the receiver not having a clock synchronized with the emitters, the method comprising the steps of: determining, for multiple pairs of emitters M1 and M2, a slice delimited by two hyperbolic surfaces revolving about the straight line linking the emitters M.sub.1 and M.sub.2, the two hyperbolas are defined by the position of the emitters M.sub.1 and M.sub.2 and a difference in length between the points of the hyperbolas at the two positions of the emitters M.sub.1 and M.sub.2, determining the position of the receiver by intersecting the slices.

5. The method according to claim 4, the difference in length between the points of the hyperbolas at the two positions of the emitters M.sub.1 and M.sub.2 are computed by: measuring the reception times of the geolocation signals emitted by the emitters M1 and M2, respectively, computing the differences dt.sub.1 and dt.sub.2 between the reception times of the geolocation signals and their time of emission by the emitters M1 and M2, respectively, computing the offset dt between the clock of the receiver and the clock of the emitters, the difference in length are equal to c.sub.1*dt.sub.1−c2*dt.sub.2−dt*(c.sub.1−c.sub.2), c1 and c2 are the propagation speeds of the geolocation signals emitted by the emitters M1 and M2, respectively.

6. The method according claim 1, further comprising, prior to, following or at the same time as receiving the geolocation signals, receiving additional electromagnetic signals comprising data used to compute and authenticate the geolocation.

7. The method according to claim 6, wherein some of the additional electromagnetic signals accompanying the geolocation signals are “information signals”, the information signal accompanying a geolocation signal comprising data relating to the position of the emitter of said geolocation signal and/or comprising an identifier providing information about the position of the emitter.

8. The method according to claim 7, wherein the information signal further comprises weather data providing information about the weather, and/or speed data providing information about the propagation speeds of electromagnetic waves in directions and at distances in which the geolocation signal is liable to be used.

9. The method according to claim 6, wherein some of the additional electromagnetic signals are received following the geolocation signals are “certification signals”, the receiver receiving, within a predetermined duration, at least two certification signals following each geolocation signal used to compute said geolocation and emitted by the same emitter.

10. The method according claim 1, further comprising computing, in addition to the position of the receiver, temporal information providing information about the time at which the geolocation signals were received.

11. The method according claim 1, further comprising computing, in addition to the position of the receiver, the speed of the receiver and the direction of said speed.

12. The method according to claim 1, further comprising the step of certifying the position of the receiver.

13. The method according to either one of claim 11, wherein the computed time, the computed speed or the computed acceleration are certified, the certification.

14. The method according to claim 1, wherein information relating to the received signals that were used to compute it and/or the accuracies on the performed geolocation computations is recorded.

15. The method according to claim 1, wherein the receiver has a map of the relief, of the surface and of the height of buildings, and of the thickness and spacings of the floors and walls and their composition, and/or the depth of the underwater surfaces and propagation speeds of the waves in these waters, and/or in the grounds at the various wavelengths liable to be received by said receiver.

16. The method according to claim 1, wherein geolocation signals originating from at least two emitters coincide in time, said geolocation signals having different wavelengths.

17. The method according to claim 1, wherein the geolocation signals are emitted on multiple different wavelengths.

18. The method according to claim 1, wherein at least one of the emitters are terrestrial.

19. The method according to claim 1, wherein the geolocation signals originating from emitters having time-synchronized clocks.

20. The method according to claim 19, wherein the clocks of the emitters taking into account the altitude and the speed at which they traveled or were located since their last synchronization in order to compute the time.

21. A receiver configured so as to: receive geolocation signals originating from a plurality of emitters, at least two emitters emitting at different wavelengths, at least one geolocation signal having a frequency less than 1 GHz, determine the geolocation of the receiver by measuring times of reception of the geolocation signals.

22. The receiver according to claim 21, further comprising a detection unit configured so as to detect the reception time of the signals emitted by the emitters.

23. The receiver according to claim 22, wherein the receiver is arranged in an indoor environment.

24. A system for implementing the method according to claim 1, comprising a plurality of emitters, each designed to emit geolocation signals, at least one of the emitters emitting electromagnetic signals in wavelength ranges different from one of the other emitters, at least one geolocation signal having a frequency less than 1 GHz, at least one receiver designed to receive the electromagnetic signals emitted by the emitters and configured so as to: determine the position of the receiver based on the geolocation signals.

25. The system according to claim 24, wherein at least two emitters each emitting geolocation signals in different wavelengths.

26. A method for certifying a transaction or a payment, wherein: the geolocation of the transaction or of the payment, or even the time of the transaction or the payment, is computed by implementing the geolocation method according to claim 1 or using the receiver according to claim 21 or using the system according to claim 24, and the geolocation and/or the geolocation of the co-signatories of the transaction or of the payment are/is optionally certified.

27. A method for securing a transaction or a payment, comprising the steps of: if the transaction is performed using two terminals remote from one another, displaying, on one of the terminals or on both terminals, the location of the other terminal, computing the geolocation of a receiver associated with a transaction or payment system by implementing the geolocation method according to any one of claims 1 to 20 or using the receiver according to any one of claims 21 to 23 or using the system according to either one of claims 24 and 25, in the event of failure of the computation, or else if the computation of the geolocation is not accurate enough with regard to a geolocation accuracy predefined for said transaction or for said payment, preventing the transaction or the payment.

28. A method for restricting the use of a license or a right by a user, wherein: the geolocation of the user, or even the time and/or the date at which the user requests access, are computed by implementing the geolocation method according to any one of claims 1 to 20 or using the receiver according to any one of claims 20 to 23 or using the system according to either one of claims 24 and 25, it is verified whether the geolocation belongs to a list of authorized positions, and/or whether said date and/or time is within a predetermined time range, and in the event of a negative outcome, preventing use of the license or the right.

29. A method for restricting access to data able to be read by an apparatus: the geolocation of a receiver associated with the apparatus, or even the time and/or the date at which the access was requested, are computed by implementing the geolocation method according to any one of claims 1 to 20 or using the receiver according to any one of claims 21 to 23 or using the system according to either one of claims 24 and 25, it is verified whether the geolocation belongs to a list of authorized positions, or even whether said time and/or the date is within a predetermined time range, and in the event of a negative outcome, declining access to the data.

30. A method for tracking a path of goods or vehicles, wherein one or more receivers periodically record the geolocation, or even the certified time and/or the certified date or the speed of the goods or the vehicle by implementing the geolocation method according to claim 1 or using the receiver according to claim 21 or using the system according to claim 24.

31. A method for geolocating a stationary object using a mobile receiver according to claim 21, said mobile receiver is geolocated by implementing the method according to claim 1, method in which the receiver receives at different times in at least two different places geolocation signals from the stationary object, and calculates the position of the stationary object by implementing the method according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0287] The invention will be able to be better understood upon reading the following detailed description of non-limiting exemplary implementations thereof, and upon examining the appended drawing, in which:

[0288] FIG. 1 schematically and partially shows a system for implementing a geolocation method according to the invention,

[0289] FIG. 2 shows one example of a geolocation method according to the invention,

[0290] FIG. 3 is a block diagram illustrating various steps of one example of a method implementing the method of FIG. 2,

[0291] FIG. 4 is a block diagram illustrating various steps of one example of a method implementing the method of FIG. 2,

[0292] FIG. 5 is a block diagram illustrating various steps of one example of a method implementing the method of FIG. 2, and

[0293] FIG. 6 is a block diagram illustrating various steps of one example of a method implementing the method of FIG. 2.

DETAILED DESCRIPTION

[0294] FIG. 1

[0295] FIG. 1 illustrates one example of a system 1 for implementing a certification method according to the invention.

[0296] This system 1 comprises a receiver 10. Preferably, the receiver 10 comprises a plurality of reception antennas, for example three of them, in particular magnetic induction-based circular ones, the antennas preferably being placed in orthogonal planes so as to be able to receive signals originating from all directions in space.

[0297] In the illustrated example, the receiver 10 furthermore comprises a detection unit configured so as to detect the reception time of the signals emitted by the emitters, said unit preferably comprising an integrated circuit or an integrated subcircuit, the circuit or the subcircuit preferably being configured so as to operate at a frequency of 60 GHz.

[0298] The receiver 10 may be arranged in any environment, in particular in an indoor environment, in particular inside a building.

[0299] As illustrated in FIG. 1, the system 1 also comprises a plurality of emitters 20.

[0300] The emitters 20 emit electromagnetic signals 23 that are used to compute the position of the receiver 10, called “geolocation signals”.

[0301] In addition to the geolocation signals 23, the emitters 20 each emit additional electromagnetic signals comprising data used to compute the position and to authenticate this position.

[0302] The additional electromagnetic signals comprise signals 25 received following the geolocation signals, called “certification signals”.

[0303] The additional electromagnetic signals comprise signals 27 accompanying the geolocation signals, called “information signals”.

[0304] The information signal 27 accompanying a geolocation signal 23 comprises data relating to the position of the emitter of said geolocation signal and/or comprising an identifier providing information about the position of the emitter, the information signal preferably comprising temporal information about the date and time of emission of said geolocation signal.

[0305] The information signal 27 furthermore comprises weather data providing information about the weather, in particular pressure, cloud coverage, temperature, hygrometry in an area surrounding the emitter, and/or speed data providing information about the propagation speeds of electromagnetic waves in directions and at distances in which the geolocation signal is liable to be used.

[0306] As a variant, the weather and speed data are accessible from a remote server 40.

[0307] In the illustrated example, the information signal 26 furthermore comprises information indicating the time at which the following certification signal should be emitted.

[0308] The certification and information signals each comprise a digital signature of the transported data.

[0309] The emitters 20 may be terrestrial. They are for example arranged at altitude or on top of buildings, in particular towers, and preferably at different altitudes.

[0310] As a variant, the emitters 20 are arranged on satellites in geostationary orbit or moving around the Earth.

[0311] Preferably, these emitters 20 are able to transmit the geolocation signals 23 and the certification signals 25 directionally.

[0312] For example, the emitters 20 each comprise a directional antenna, for example a dipole antenna. As an alternative, the emitters 20 each comprise a director and/or reflector arranged in the trajectory of the signal emitted by the emitter so as to direct it in a predefined direction.

[0313] FIG. 2

[0314] A description will be given below, with reference to FIG. 2, of a geolocation method according to the invention.

[0315] Step 101 corresponds to the receiver 10 receiving geolocation signals 23 emitted by the emitters 20.

[0316] Prior to, or at the same time as or following step 101, the geolocation signals are analyzed in step 102 with a view to verifying their authenticity. To this end, the system 1 may comprise a plurality of inspection terminals 30.

[0317] The authenticity of the geolocation signals is verified by each inspection terminal 30 by verifying the digital signature of the information and certification signals, by computing an average transmission speed of the geolocation signals between their emitters and the inspection terminal, and by comparing said computed average transmission speed with a range of possible transmission speeds.

[0318] In the example, the range of possible transmission speeds is determined taking into account the weather situation, including in particular atmospheric pressure, temperature and the hygrometry of the spaces traveled through by the signal between its emitter and the inspection terminal.

[0319] If the result of the analysis performed for a geolocation signal 23 in step 102 is negative, that is to say if the transmission speed of this signal is not within the range of possible values and/or if all of the data in the message attached to the signal are not valid, then a predefined action for fraudulent signals is triggered in step 103 so as to prevent the emitter emitting the fraudulent geolocation signal from sending a certification signal following this fraudulent signal or the receiver from receiving this certification signal.

[0320] In the illustrated example, the predefined action for fraudulent signals comprises jamming, in particular by way of one or more jamming stations associated with the inspection terminal, the certification signal expected by the receiver 10 for certifying the geolocation following the reception of the fraudulent geolocation signal.

[0321] In the illustrated example, the jamming is limited to an area Z defined by: [0322] (i) the position of the emitter 20 of the imprecise geolocation signal 23, computed by trilateration using the inspection terminals, and by [0323] (ii) a power of the geolocation signal 23, the identified area Z corresponding to an area that has been traveled through by the imprecise geolocation signal with a signal power greater than or equal to a minimum threshold.

[0324] The minimum threshold may be predetermined for an emitter of the plurality of emitters, for a group of these emitters, or for all of these emitters, below which threshold the receiver is not able to use said certification signal to certify a geolocation.

[0325] By contrast, if the result of the analysis is positive, the receiver receives, in step 104, a first certification signal 25 from each emitter that emitted the geolocation signals 23.

[0326] In the same way as for the geolocation signal, the method may comprise a step 105 in which the authenticity of the certification signal is verified by the inspection terminals 30.

[0327] If the result of the analysis performed for the certification signal 25 in step 105 is negative, then a predefined action for fraudulent signals in step 106 is triggered in order to prevent the emitter emitting the fraudulent certification signal from sending a second certification signal following this fraudulent signal or the receiver from receiving this second certification signal.

[0328] Like the geolocation signal, the predefined action is preferably the jamming of the second fraudulent certification signal.

[0329] By contrast, if the result is positive, the receiver receives a second certification signal, in step 107, from each emitter that emitted the geolocation signal and the first certification signal.

[0330] The receiver computes its position in step 108 using the geolocation signals if it has not yet been computed. In the illustrated example, the position of the receiver 10 is computed by trilateration.

[0331] In this computing step 108, the receiver may furthermore compute time information providing information about the time at which the geolocation and/or certification signals were received.

[0332] The method also comprises, in step 108, computing, in addition to the position of the receiver, the speed of the receiver and the direction of said speed.

[0333] Preferably, the method comprises, in step 109, certifying the position of the receiver. With a view to certification, the receiver computes its position a second and a third time using the first and second certification signals.

[0334] The computation using the first certification signals following the geolocation signals is used to verify that these certification signals have not been jammed by an inspection terminal or a jamming station controlled by an inspection terminal.

[0335] The computation using the second certification signals makes it possible to verify that the inspection system has not detected any anomaly with its operation during the potential jamming of the first certification signal.

[0336] If no problem was detected in these position computations, then the receiver may certify, in step 110, its position computed in step 108 using the geolocation signals.

[0337] Preferably, the position of the receiver may be certified using an encrypted hash using an asymmetric cipher whose private key is stored in the emitter 20.

[0338] Step 110 also comprises certifying the computed time and/or the computed speed of the receiver, the certification is preferably performed using an encrypted hash, using an asymmetric cipher whose private key is stored in the emitters 20.

[0339] Step 111 comprises storing the computed position of the receiver and the computed time, along with information relating to the received signals that were used to compute them.

[0340] The storage is performed in a storage unit of the system, in particular of the receiver.

[0341] As a variant, this information is transmitted to a remote server 40 in order to be stored there.

[0342] In the illustrated example, the position of the receiver and/or the time and/or the speed of the receiver are stored and/or transmitted with information relating to the accuracy with which this information was computed.

[0343] This information may be stored and/or transmitted with information relating to the received geolocation signals that were used to compute it.

[0344] FIG. 3

[0345] FIG. 3 illustrates one example of a method for securing a transaction according to the invention.

[0346] As illustrated, in step 201, the position of a receiver associated with a transaction system is computed, or even certified by implementing the geolocation method described above.

[0347] In the event of failure to compute said position or to certify the position, the transaction is prevented in step 202.

[0348] FIG. 4

[0349] FIG. 4 illustrates a method for restricting the use of a license or a right by a user according to the invention.

[0350] This method comprises, in step 301, determining the position of the user, or even the time at which the user requests access, by implementing the geolocation method described above.

[0351] In step 302, it is verified whether this position belongs to a list of authorized positions, or even whether said time is within a predetermined time range.

[0352] If not, the use of the license or the right is prevented, this corresponding to step 303.

[0353] FIG. 5

[0354] FIG. 5 illustrates a method for restricting access to data able to be read by an apparatus according to the invention.

[0355] This method comprises, in step 401, geolocating is carried out, and optionally certifying the geolocation of, a receiver associated with the apparatus and the time at which access was requested by implementing the geolocation method described above.

[0356] In step 402, it is verified whether the geolocation belongs to a list of authorized positions, or even whether said time is within a predetermined time range, and

[0357] If not, access to the data is declined in step 403.

[0358] FIG. 6

[0359] FIG. 6 illustrates one example of a method for certifying a transaction according to the invention.

[0360] In step 501, the transaction, or even the time of the transaction, is geolocated by implementing the geolocation method according to the invention and optionally this geolocation as well as that of the co-signatories of the transaction is certified.

[0361] In step 502, the computed geolocation, or even the computed time of the transaction, is compared with a geolocation, or even a transaction time declared by the co-signatories, and optionally the geolocation of the co-signatories of the transaction is compared with a declared geolocation of the co-signatories.

[0362] In the event of a difference, the certification of the transaction is declined in step 503.

[0363] In the opposite case, the transaction is certified in step 504.

[0364] Of course, the invention is not limited to the described examples.