FR2951889A1 - Data transmitting method for e.g. radio transmitter/receiver carried by soldier in military application, involves receiving electrical signal corresponding to data in electronic equipment, and processing signal for recuperating data - Google Patents

Abstract

The method involves connecting electronic equipments e.g. computer (3), radio transmitter/receiver (4) and telescope sight (5), by a connection establishment unit for forming a data transmission circuit between the equipments, where one of the established connections implements external capacitive coupling. An electrical signal corresponding to the data is introduced in the transmission circuit from one of the equipments, such that the signal transits in the form of field in the connection. The signal is received in another equipment, and the signal is processed for recuperating the data. An independent claim is also included for an assembly of electronic equipments, comprising an electrical signal processing unit.

Description

The present invention relates to a method of data transmission between two electronic equipment carried by at least one user. The invention also relates to a set of at least two devices for implementing this method. Advances in electronics and computers, miniaturization of components and increased battery life have enabled some professionals, such as soldiers, to equip themselves with electronic devices or equipment to provide them with assistance. fulfillment of their missions. Among these electronic equipment, there is, in a nonlimiting manner, a display device which is housed on the helmet and allows a close vision and / or in low light condition, a communication assembly comprising a transmitter / receiver associated with a microphone and to a listener, a computer allowing the recording and / or the consultation of information, a telescope mounted on the weapon ... These different equipments are connected to each other in such a way that, for example, Images from the viewfinder or display device can be transmitted to the computer for storage in the transmitter and the transmitter / receiver for transmission to the command center. Similarly, electrical signals from a keypad or any command on equipment may be received and executed by other equipment located some distance from the first. The equipment is fixed or inserted into pockets in different places of the soldier's clothing, as well as on his helmet, on his weapon, etc. The equipment is connected to each other via cables that can reach a total length of several meters and a weight of several kilograms. These cords are integrated into the garment as much as possible, but go beyond it (for example, the one who climbs towards the helmet or the one who goes towards the weapon) and risks being hooked during the evolutions of the soldier. In addition, the movements of the soldier or the falls of the latter may involve the exercise of tensile force, torsion, shear on both the cables and the connectors that connect them to the equipment. Connectors may also be fouled by the presence of sludge or sand and must be sealed, connected or not, to prevent moisture from establishing electrical leaks and electrolytically destroying the connector contacts. Protective measures of cables and connectors, such as the integration of these in the clothing and the presence of waterproof caps, increase the weight of the garment and the cost of it. The connections are also a fragile area whose relative unreliability can jeopardize a mission. It has been envisaged that at least part of the wired links will be replaced by wireless links and particularly radio links such as those complying with the IEE 802 standard. However, such radio links have disadvantages: they can be detected , intercepted and / or scrambled, - they assume the presence of antennas with a directivity, all the more important as they are close to the body, and a sensitivity to polarization which can prevent the transmission of data in certain positions of the soldier. Infrared wireless links have also been envisaged, but these do not bring any significant improvements to the aforementioned drawbacks. An object of the invention is to provide a means for transmitting signals while minimizing the use of wired links while at least partly improving the aforementioned drawbacks. Considering that the desired transmission distance is small (a few cm to 1 m), the proposed solution uses an electric field (also called near field or unformed field) as a means of transmission. Unlike the electromagnetic waves used in the radio solution, an electric field alone is created by the surface of any conductor carried under tension. If this voltage is modulated, the field is also modulated and the modulation is transmitted to another non-zero surface conductor, which will then constitute the second armature of a capacitor. For this purpose, according to the invention, a method of data transmission between a first electronic equipment and a second remote electronic equipment is provided, the method comprising the steps of: connecting the two devices by means of a first link and a second link for forming a data transmission circuit between the devices, the first link implementing at least one external capacitive coupling and the second link implementing at least one external capacitive coupling or a conduction for example in the body of the user, since the first equipment introduce into the transmission circuit an electrical signal corresponding to the data in such a way that the signal transits in the form of a field in the connection (s) operating by capacitive coupling, and in the form of a current in the bond or the connecting portion using a conduction with for example the body as a conductor, - rec have the signal in the second equipment and process the signal to retrieve the data.

Since the distance separating the equipment is small because it is limited to the dimensions of the body of the user in the case where the equipment is worn by the user, the conductive surfaces can have any shape since their dimensions are small relative to the user's body. at the greatest distance of transmission envisaged. The transmission of electric fields is possible even if the surfaces extend in perpendicular planes. This is all the more interesting as the transmission of the electric field is insensitive to corrosion, the conductive surfaces can also be covered with an insulating coating. By external capacitive coupling is meant that the capacitive coupling is established outside the equipment, in the "open air" and not inside an electronic component. The electrical signal may be continuous or alternating and be a control signal or a data signal. The signal is, for example, modulated to transmit data and the field is therefore modulated accordingly. A simple demodulation at the second equipment therefore allows, after capture, amplification, and possibly shaping of the electrical signal, to recover the data contained therein.

The invention also relates to a set of equipment each comprising an electrical signal processing unit connected to a first electrically conductive plate and a second electrically conductive plate which are arranged to establish two links with the other equipment so forming a data transmission circuit between the equipment, the first plate of each equipment being arranged to be fixed substantially facing and in the vicinity of the skin of a user, the equipment processing units being arranged to implement the procedure as above. Other features and advantages of the invention will emerge on reading the following description of particular non-limiting embodiments of the invention. Reference is made to the accompanying drawings, in which: FIG. 1 represents in elevation a set of equipment according to the invention, FIG. 2 is a schematic view illustrating the principle of operation of the method according to a mode of implementation. FIG. 3 is a diagrammatic perspective view with cutaway of an equipment of an assembly according to the invention; FIG. 4 is a partial sectional view of an assembly according to the invention; invention in position on the body of the user, - Figure 5 is a partial top view with cutaway of an assembly according to a second va-laughing implementation of the invention, - Figure 6 is a cross-sectional view illustrating a connection means between equipment in this variant.

With reference to FIGS. 1 to 3, the equipment assembly according to the invention is here incorporated into a garment, generally designated 1, having the shape of a vest intended to equip a soldier and comprising a plurality of pockets of which some receive equipment. These devices are here a computer 3, a radio transmitter / receiver 4, a window 5 integral or not with a weapon 6. Each equipment 3, 4 comprises a housing 7 of electrically insulating material containing a processing unit 12 arranged to ensure the transmission and reception of electrical signals carrying data and capable of extracting, from an electrical signal received, the data contained therein. The housing 7 comprises an outer lower face covered with a plate 13 made of electrically conductive material and an outer upper surface covered with a metallization layer forming an electrically conductive plate 14. The plates 13, 14 can be in the housing and / or have identical structures. The plates must be remote from the conductive parts such as the integrated circuit boards of the processing unit in order to avoid a capacitive overload in transmission mode and an unfavorable capacitive ratio in reception mode. If to keep a reduced thickness to the housing, this is not possible, the plates can be offset (see the description of the bezel 5) or have a frame shape framing the housing. The bezel 5 comprises a housing enclosing a processing unit connected to conductive plates 9, 10 offset and secured to the grips 11 of the weapon. Each of the devices 3 and 4 is received in the pockets of the garment 1 in such a way that the electrically conductive plate 13 opens onto an inner surface 8 of the garment 1 (only the plate 13 of the computer 3 has been shown). The transmission method of the invention is here described in connection with the transmission of data, for example between the radio transmitter / receiver 4 and the computer 3. The method is implemented by connecting in series the equipment 3, 4 by a first link I and a second link II to form between these two devices a data transmission circuit. The link I implements a capacitive coupling. The link II implements a current conduction in the body H of the user. The data transmission method comprises the steps of: - from one of the equipment, for example the radio transceiver 4, introducing into the body of the user an electrical signal corresponding to the data, for example audio (analog signal called "audio" or digital signal), so that the signal passes through the link II and thus into the user's body and into the link I by capacitive coupling between the plates 14, - receive the signal in another equipment, for example the computer 3, and process the signal to extract the data. The signal emitted here is an alternating signal modulated at a predetermined frequency or a digital signal itself transmitted as such or after modulation. It is possible to provide as many carrier frequencies or types of modulation or sequential or non-sequential modulation codes (TDMA, CDMA, DSL for example) as equipment to avoid interference between the signals or to select the receiving equipment of the device. signal using for transmission the frequency or the coding or recognition means (multiplexing techniques) assigned to this equipment. The plates 13 are fixed on the inner face of the garment with regard to the equipment worn by the garment. When the plates 13 are in direct contact with the skin of the user, an electrical contact is established between each plate 13 and the body of the user so that the data signal is transmitted by conduction of a current between the equipment via the user's body. When a layer of clothing, such as an undergarment or lining of the garment 1, is interposed between the plates 13 and the skin, this layer of clothing does not interfere with the transmission of the signal via the body between the equipment. , a capacitive coupling is established between each equipment and the body allowing the transfer of signals in the form of electric field between each equipment and the body, and the signals passing through the body by conduction in the form of current. It is thus understood that several layers of clothing could be interposed between the plates and the body of the user. When the inter-posed garment is dirty or wet (perspiration, rain, fording), the transmission is not degraded, it is instead improved. It can be expected that the garment and the plates are in direct contact with the skin of the user such as the plate 9 of the telescopic sight 5 which is in direct contact with the skin of the user when the latter does not wear gloves while the plate 10 is left uncovered for a capacitively coupling connection or in contact with an electrically conductive surface covering the skin or the garment for transmission of the electrical signal by both conduction and capacitive coupling. Conduction transmission is particularly useful for the transmission of continuous or low frequency signals. Capacitive coupling transmission is effective for higher frequencies and is sufficient when the transmission of a DC component is not necessary. In the variant of Figure 4, the garment 1 comprises an electrically conductive layer 16 which is in contact with the plates 14 of the equipment 3, 4. The conductive layer 16 comprises for example conductive particles embedded in the fabric of the garment, fibers conductors mixed with the fabric of the garment or a conductive coating attached to the garment. The fabric is made conductive during weaving (by the insertion of conductive fibers) by impregnation or even by deposition (coating or particles). The link I then transmits the signal by conduction in the conductive layer, which makes it possible to limit the attenuation of the signal, and by capacitive coupling at the level of the conductive layer / plate interfaces 14. In the variant of FIG. garment 1 comprises a conductive layer formed of two strips 16.1, 16.2 independent to form the link I. The strips 16.1, 16.2 respectively connect: - the plate 14.1 of an equipment 15 to the plate 14 of the computer 3, - the plate 14.2 of the equipment 15 to the plate 14 of the radio transceiver 4. The link II between the equipment 3, 15 and the equipment 4, 15 is of the same type as that previously described. Simultaneous communication of the equipment 3 and 4 with the equipment 15 is thus possible.

FIG. 6 shows the strip 16.1 separated in two sections 16.1.a and 16.1.b which are connectable via an electrically-conductive button, a portion 17.a of which is integral with the section 16.1.a and a portion 17.b is in solidarity with section 16.1.b. The pushbutton can be used as a switch. Other connection methods are possible and for example VELCRO self-gripping elements, zippers ... Of course, the invention is not limited to the embodiments described but encompasses any variant within the scope of the invention. the invention as defined by the claims. In particular, although the invention has been described in a military application, civil applications are quite feasible for communicating electronic equipment worn by the city such as telephones, cameras or music players. The electrical signals may be of alternating modulated or non-modulated type, or alternating with DC component. If the quality of the signal received is too low, partly because its level must be limited to the emission so as not to present a discomfort (or of course a danger) physiological, and account also on the other hand. As it undergoes attenuation and distortion in the body, it is possible to use different types of analog modulations, and in particular frequency, amplitude, single-sideband, phase, quadrature, or other modulations. , but also numerical modulations whose list is not limited either. All known signal extraction techniques can be favorably used.

If necessary, to reduce the attenuation of the signal, it is possible to increase the transmission frequency, use plates of larger areas or decrease the capacity existing between the two plates (dedicated to the links II and I respectively).

The signal processing for extracting the data can be a digital or analog processing, possibly associated with corrections in case of non-linearity and / or data recovery techniques lost in case of BER (Bit Error Rate ) Student.

The signals can also be multiplexed. The plates can be arranged on the sides of the housings. The equipment may comprise several plates each dedicated to the formation of a link II with other equipment.

The two links established between the devices can implement a capacitive coupling, without conduction by the human body, especially when the equipment is far from the human body and more generally from an electrically conductive element. It is obvious that the equipment must however be sufficiently close to each other to allow the capacitive coupling to be established. Each link may implement one or more capacitive couplings and / or one or more conductions.

Claims (15)

REVENDICATIONS1. A method of transmitting data between a first electronic equipment and a second remote electronic equipment, the method comprising the steps of. connecting the two devices by means of establishing a first link and a second link to form a data transmission circuit between the devices, at least the first link implementing at least one external capacitive coupling. from the first device, introducing into the transmission circuit an electrical signal corresponding to the data in such a way that the signal transits in the form of a field in the first link; receiving the signal in the second device and processing the signal to recover the data; . 2. The method of claim 1, wherein the second link implements at least one capacitive coupling. 3. The method of claim 1, wherein the first link implements several capacitive couplings in series. 4. The method of claim 1, wherein the setting means are arranged for the second link implements a conduction, the electrical signal corresponding to the data transiting in the form of current in the second link. 5. The method of claim 4, wherein, the equipment being worn by at least one user in the vicinity of his body, the second link passes through the body of the user. 6. The method of claim 5, wherein the establishment means are arranged to establish an electrical contact between each equipment and the body of the user. 7. The method of claim 5, wherein the setting means are arranged to form a capacitive coupling between each equipment and the body of the user. 8. The method of claim 5, wherein the conduction is done directly in the body of the user. 9. The method of claim 5, wherein the conduction is by a conductor extending on the skin of the user. An assembly of at least two devices each comprising an electrical signal processing unit connected to a first electrically conductive plate and a second electrically conductive plate which are arranged to establish two links with the other equipment so as to form a circuit. transmission of data between the equipment, the second plate of each equipment being arranged to be fixed substantially opposite and in the vicinity of the skin of a user, the equipment processing units being arranged to implement the method according to preceding claims. 11. The assembly of claim 10, wherein the equipment is integral with a garment, the first plates of the equipment opening on an inner surface of the garment. 12. The assembly of claim 11, wherein the garment comprises an electrically conductive layer extending opposite the first plates of the equipment. 13. An assembly according to claim 12, wherein the conductive layer comprises at least one of the following elements: an electrically conductive product impregnating a part of the garment; an electrically conductive product sprayed on a part of the garment; electrically conductive extending in a fabric of the garment; - an electrically conductive film fixed facing a part of the garment. 14. The assembly of claim 11, wherein the garment comprises a layer extending facing the second plates of the equipment. 15. The assembly of claim 10, wherein one of the equipment is integral with an object having a gripping area for a hand of the user and the second plate of the equipment is fixed on the gripping area.