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
  • 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
  • G01S5/0247—Determining attitude
• • 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
• • 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
  • G01S5/14—Determining absolute distances from a plurality of spaced points of known location

Definitions

• Positioning system in a place opaque to the signals of a satellite navigation system.
• the present invention relates to a terrestrial positioning system enabling a user to know his position and his orientation in a place opaque to the signals emitted by known satellite navigation systems. It is known that satellite navigation systems generally allow a terrestrial user to determine his position and, possibly, his altitude.
• the present invention aims to overcome this disadvantage.
• the system for the terrestrial positioning of a user in a place where the signals emitted by the satellite navigation systems can not be received is remarkable in that it comprises:
• each beacon arranged around said place, outside of said place, and able to emit radio signals comprising information on their respective terrestrial positions, the transmission wavelength of each beacon being at less decametric;
• At least one equipment associated with said user comprising at least: reception means able to receive said radioelectric signals emitted by said beacons, calculating means capable of calculating, from said radio-electric signals emitted by said beacons, the land position and orientation of said equipment, and indicating means able to inform said user of the land position and orientation of said equipment; equipment thus calculated.
• the present invention is based on the observation that the cause of the opacity of said locations to the signals emitted by the satellite navigation systems lies in the small wavelength (of the order of 20 cm) of said signals. On the contrary, according to the invention, it implements significant wavelengths, at least HF and, preferably, MF and even Telec, able to transmit the beacon position information inside said opaque locations. microwave signals from satellite navigation systems.
• the calculation means are able, by known calculation methods, to determine the position and the orientation of said equipment (that is to say of said user) relative to said beacons and, by following, the land position and orientation of that equipment.
• the emission wavelengths of said beacons may be different from each other, each wavelength being specific to a beacon.
• said receiving means can identify each beacon by its own transmission frequency and said beacons can transmit simultaneously.
• said transmission wavelengths of said beacons may be identical, said radio signals emitted by said beacons then comprise identification codes specific to each of them and identifiable by said reception means.
• said beacons must emit alternately.
• said beacons may comprise input means, such as for example a keyboard, so that an operator can communicate said information to them on their positions. This information can be recorded by said operator using a geographical map or indications given by a satellite navigation system.
• said beacons may comprise means for receiving and processing signals transmitted by a satellite navigation system.
• each beacon comprises receiving and processing means able to listen to the electrical signals emitted by the other beacons.
• the operation of the system according to the invention is done from a master beacon, installed first, the triggering of the other beacons taking place in cascade as and when they are installed .
• the user can know his position and his orientation before the end of the deployment of all the beacons of the system.
• said means for receiving said equipment associated with the user comprise at least three loop-type antennas whose planes are not coplanar. Preferably, these planes are two to two orthogonal.
• the user of the system according to the invention can be of any kind, for example it can be a robot or a human being.
• said antennas are arranged on a headset, able to be worn by the head of said user.
• a portable housing by said user.
• Such a housing can be sealed to allow use in water or in the presence of an aggressive medium.
• said indicating means it is advantageous for said indicating means to be able to represent the position and orientation of said user, human or not, on a map, a map of said place or any other similar geographical reference. It will be noted that the system according to the invention has the advantage of requiring no equipment, other than that associated with the user, within said location. Its implementation can therefore be particularly discreet.
• Figure 1 is a schematic plan view showing a plurality of beacons arranged around a place opaque to the signals of the satellite navigation systems.
• FIG. 2 shows the block diagram of an exemplary beacon implemented by the invention.
• Figures 3 and 4 are views, respectively from the side and from above, of a helmet equipped with loop type receiving antennas.
• FIG. 5 shows the block diagram of an example of equipment associated with said user and adapted to the helmet of FIGS. 3 and 4.
• Figures 6 and 7 are views respectively similar to Figures 3 and 4, a helmet variant used by the present invention. '
• FIG. 1 there is shown a user 1 (for example a human operator) located in a place 2 (for example a building, a forest, an underground structure, etc.) inside which the signals emitted by a satellite navigation system can not be received.
• a place 2 for example a building, a forest, an underground structure, etc.
• a plurality of beacons 3 designated respectively by the references 3.1, 3.2, 3.3, ..., 3.n (n being an integer at least equal to 3), able to emit on a carrier of wavelength at least decametric, but preferably hectometric or kilometer.
• each tag 3.1, 3.2,..., 3.n comprises:
• a transmitter 4 capable of transmitting on such a wavelength and provided with a transmitting antenna 5, of the magnetic loop type, of axis x-x;
• Such means 6 may comprise equipment 6A receiving position signals 7 of a satellite navigation system and / or a keyboard 6B (or any other similar means) capable of manually entering position information, for example recorded on a map ; a receiver 8 enabling each beacon 3.1, 3.2, ... to listen to the transmissions of the other beacons, thanks to a receiving antenna 9, also of the magnetic loop type; and
• each beacon can, thanks to its transmitter 4 and its antenna 5, send to the user 1 located in said location 2, a radio signal 11 constituted by a decametric, hectometric or Telec carrier modulated by the information of its own position.
• each beacon 3.1, 3.2, ... receives the radio signal emitted by the other beacons: in FIG. 2, the signal thus received by a beacon is symbolized by the arrow 12.
• the carriers of the different tags 3.1, 3.2, ..., 3.n can have different frequencies, to identify them. However, for the purpose of simplification, all tags preferably use the same carrier frequency. It is then essential that the transmitter 4 of each beacon incorporates the radio signal 1 1 it emits an identification code of the corresponding beacon.
• each transmitter 4 can incorporate further information in its radio signal 11.
• the processors 1 0 of each of them control the corresponding transmitter 4 so that, at each moment, only one of said tags emits its signal radio 1 1.
• an advantageous sequencing mode allowing a gradual deployment of the n tags 3.1, 3.2, 3.3 ... around the zone 2, while ensuring a service to the user 1 during this deployment, is the following (considering by example that n is equal to 7 and that a sequencing cycle is divided into n + 1 ⁇ 8 phases):
• the first beacon 3.1 installed around zone 2, serves as master to initialize the sequence: it transmits its radio signal 11 for one-eighth of the time, repeats it to occupy the 7 eighths of the following time and listens during the last eighth of the time;
• the second beacon 3.2 to be installed listens to the first beacon 3.1 (radio signal 1 2), deduces that its code is 2 and transmits its signal 1 1 during the silence of said first beacon 3.1: the latter having heard the second beacon 3.2 delays its transmission recovery by one-eighth cycle and also reduces its transmission time by one-eighth cycle;
• the third tag 3.3 to be installed listens to the first tag 3.1, then the second tag 3.2, and deduces that its code is 3; she emits her radio signal 1 1, immediately after the transmission of the signal 1 1 of the second beacon 3.2;
• the first beacon 3.1 which listens to the beacons 3.2 and 3.3, delays its resumption of transmission by one eighth cycle and, in addition, reduces its transmission duration by also one eighth of a cycle;
• the user 1 is equipped with reception means 20 able to receive the radio signals 11 emitted by the beacons 3.1 to 3.n, means 21 for processing said signals.
• receivers comprising calculation means 22 able to calculate, from said signals, the land position and orientation of said equipment, and indicating means 23 able to inform said user of the land position and orientation of said equipment.
• the means 20 to 23 are made so as to be easily carried by said user 1.
• the means 21, 22 and 23 are incorporated in a portable box B, while, as represented by FIG. 3, the reception means 20 allowing directional reception of the radio signals 11 emitted by the beacons 3.1 to 3. n have three antennas 24, 25 and 26 incorporated in a helmet 27 adapted to be worn by the head of the user 1.
• the antennas 24, 25 and 26 are of the loop type and they are arranged so that their respective axes X, Y and Z form a three-dimensional orthogonal axis system serving as a geometric reference for the user 1, that is to say to say that the planes of said antennas are two to two orthogonal.
• the processing means 21 comprise, for each antenna 24, 25, 26 (see FIG. 4), a band-pass filter 28, an amplifier 29 and a sampler 30, carrying out the filtering, the amplification and the sampling. simultaneous transmission of the signals received from the three antennas 24, 25 and 26.
• the processing means 21 further comprise an analog-digital converter 31 receiving the signals from the three samplers 30 and addressing them to the calculation means 22. These control the three samplers 30 and, as needed, adjust the gain of the three amplifiers 29.
• the calculation means 22 calculate, for each tag 3.1 to 3.n (by known mathematical methods):
• the computing means 22 calculate the apparent angles between said beacons, then (by the known method of the able arcs) the position and the orientation of the user 1 with respect to the beacons 3.1 to 3.4. Since the terrestrial positions of the latter are known (by the means 6), the calculation means 22 derive from them the position and the earth orientation of said user 1. These are transmitted to the indication means 23, which may include a system for displaying this position and this orientation on a map or a plan of said place 2.
• FIGS 6 and 7 there is shown a helmet 40, similar to the helmet 27, provided with four loop antennas 41 to 44 arranged in a tetrahedron.
• the previous calculations must take into account the angles between said antennas to deduce the directions of the tags in the geometric reference of the user.
• Such an embodiment with four antennas has the advantage that, whatever the direction of the beacons, it is safe to have at least three non-zero signals, which allows an excellent resolution of the equations, even in the presence of noise electric.
• the present invention is not limited to determining the position and orientation of a single user 1: on the contrary, what has been explained above can be applied to a plurality of users 1 lying in the place 2.
• one of the advantages of the present invention resides in the fact that it does not require any preinstalled equipment inside the locus 2, so that its implementation can be particularly discrete.
• possibly some users may themselves be equipped with a transmitter also working at low frequency to transmit their calculated position from the external tags, thus acting as a complementary tag and thereby allowing other users 1 to include this information in the calculation of their own positioning.
• these complementary beacons can be listened from outside to know the position of the complementary beacon carriers.

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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)
• Position Fixing By Use Of Radio Waves (AREA)

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• 2008
  • 2008-02-20 FR FR0800912A patent/FR2927704B1/fr not_active Expired - Fee Related
• 2009
  • 2009-02-16 EP EP09722465A patent/EP2245476A2/de not_active Ceased
  • 2009-02-16 WO PCT/FR2009/000169 patent/WO2009115676A2/fr not_active Ceased
  • 2009-02-16 US US12/867,076 patent/US8698672B2/en not_active Expired - Fee Related

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