FR3114460A1 - UWB RADIO TRANSMITTER DEVICE COMPRISING A PHYSICAL PROPERTY STATE SENSOR FOR ITS TRANSMISSION - Google Patents

Abstract

UWB RADIO TRANSMITTER DEVICE COMPRISING A PHYSICAL PROPERTY STATE SENSOR FOR ITS TRANSMISSION UWB radio transmitter device (EM1) comprising a UWB radio transmitter module and a UHF radio receiver module for collecting signals in order to electrically supply the UWB transmission module, characterized in that said UWB tag comprises a state sensor of a physical property of an element of said sensor (C1), a change of state of said physical property of the element (ELT1) resulting in a modification of an electrical state of an electrical interface (I/O1) of said sensor (C1), the transmission of a UWB signal comprising the transmission of a datum corresponding to the electrical state of the interface electric. Figure for abstract: Fig. 1

Description

UWB RADIO TRANSMITTER DEVICE COMPRISING A PHYSICAL PROPERTY STATE SENSOR FOR ITS TRANSMISSION

Field of invention

The field of the invention relates to the field of UWB radio transmitter devices, of the radio tag type, comprising a UHF radio energy reception module to supply the electronic components of said transmitter device. The field of the invention relates to transmitter devices associated with physical sensors.

State of the art

There are transmitter devices of radio tag type collecting radio energy to supply the electronic components of said tag. However, the existing solutions do not make it possible to send a state variable other than data recorded in a memory of the tag for lack of sufficient energy.

There is a need to define a transmitter device which sends back a physical variable from a sensor when the latter is not powered or does not have enough energy to transmit such a variable.

According to one aspect, the invention relates to a UWB radio transmitter device comprising a UWB radio transmitter module and a UHF radio receiver module for collecting signals in order to electrically power the UWB transmitter module, characterized in that said tag UWB comprises a state sensor of a physical property of an element of said sensor, a change of state of said physical property of the element leading to a modification of an electrical state of an electrical interface of said sensor, the transmission of a UWB signal comprising the transmission of a datum corresponding to the electrical state of the electrical interface.

An advantage is to allow to physically store a state of the sensor which will be transferred when the tag has enough energy. According to one embodiment, the state of the physical property is sent regularly each time a UWB message is sent.

According to one embodiment, changing the state of the physical property passively affects the electrical conductivity of a physical region of the sensor. This region preferably forms an electrical interface of said transmitter device. It is connected to the reading inputs of a transmitter device electronic chip, the transmission of a UWB signal comprising the reading of the electrical state of said electrical interfaces and the transmission of data corresponding to said electrical state.

According to one embodiment, the transmission is carried out from the energy collected by the UHF radio reception module.

According to one embodiment, the data transmitted further comprises an identifier stored in a memory of the transmitter device and data characterizing the type of sensor.

According to one embodiment, the modification of the state of the physical property relates to a modification of a chemical property of a material, to a modification of the conductivity of a zone of said sensor, to a modification of the mechanical state of a zone of said sensor.

According to one embodiment, the modification of the conductivity of a zone of said sensor corresponds to a modification of the voltage, of the impedance of said zone.

According to one embodiment, the sensor is made removable from the transmitter device.

According to one embodiment, when sufficient energy is collected by the UHF radio wave reception module, the UWB transmission module automatically reads the value of the physical state of the sensor and automatically transmits a UWB message comprising said data .

When it wakes up, the sending device reads at least two inputs from a microchip. At least one of the data can be data saved in memory.

The UHF radio wave receiving module generates energy within an electrical energy storage capacity. The electrical energy is for example obtained from a rectifier to transform the analog signal into an electrical signal.

According to one embodiment, the sensor is a sensor from among the set of following sensors:

• a shock sensor comprising an accelerometer;
• a tread;
• a mechanical witness of a seal;
• a container of a chemical reagent;
• a sensor comprising a thermofusible material;
• a pressure sensor;
• a humidity sensor comprising a pellet whose conductivity is modified when the humidity of said pellet exceeds a threshold;
• a usage counter;
• a pull-out detector.

Other characteristics and advantages of the invention will become apparent on reading the following detailed description, with reference to the appended figure, which illustrates:

• [Fig.1]: an exemplary embodiment of the invention comprising a transmitter device associated with a sensor of a physical state.

The “UWB” notation designates the “Ultra Wide Band” frequency band in English terminology. The "UHF" notation designates the "Ultra High Frequency" band in English terminology.

FIG. 1 represents an embodiment of a transmitter device EM ₁ associated with a sensor C ₁ . According to one embodiment, the transmitter device EM ₁ comprises the sensor. According to another embodiment, the transmitter device EM ₁ can be associated with a removable sensor C ₁ . These two parts EM ₁ and C ₁ can be part of the same object, or be clippable with each other. When the two parts {transmitting device; sensor} are clip-on, the object may consist of a radio plate attached to a base support of the sensor.

The transmitter device EM ₁ comprises an antenna ANT ₀ making it possible to receive radio signals to supply the components of the transmitter device EM ₁ and more particularly a UWB radio transmitter module transmitting signals in the UWB band. The UWB antenna is not shown in Figure 1.

The sensor C ₁ comprises an element ELT ₁ whose physical modification causes a change of state of an electrical interface I/O ₁ . One advantage is to allow an electronic chip (not shown) of the transmitter device to read the electrical state of the electrical interfaces in order to integrate the data read into a UWB message when the latter is transmitted.

An advantage is to save a data during a long sleep time of the transmitter device and to transmit the latter when the radio transmitter wakes up when it receives enough radio energy.

According to one embodiment, the transmitter device EM1 is a radio tag, also called TAG. It includes a transmission function in the UWB band and a reception function in the UHF band.

According to one embodiment, the sensor C1 is based on a mechanical, chemical, etc. aspect. in order to persist in its state and operate without electrical energy. The mechanical/chemical sensor behaves like a state switch. The state will be read by the I/O1 interface of the radio transmitter device part EM ₁ .

The UWB radio transmission module has at least one input of an electrical I/O interface for retrieving a state at the time of sending. According to another embodiment, the transmitter device EM ₁ comprises a function making it possible to inhibit the transmission of the UWB signal or to cause spontaneous transmission depending on the mechanical, chemical or electrical state of the sensor C ₁ , for example by a switch function of the sensor C ₁ . In another case, depending on the value of the mechanical, chemical or electrical state of the sensor C ₁ , the UHF wave reception function for energy collection can be active or inhibited.

If the electronic chip of the transmitter device EM ₁ does not include a read I/O, according to one embodiment, a sensor switch is implemented to stop the UWB transmission or to stop the collection of UHF waves for their conversion into electrical energy.

In the latter case, the non-reception of UWB signals by the beacons may mean that the switch is open. On the other hand, the emission of UWB signals and therefore their reception by at least one beacon can mean that the switch is closed.

According to one embodiment, to avoid false positives/negatives, the transmitter device of the invention may comprise two electronic chips making it possible to read two pieces of information on the I/O ₁ electrical interfaces. The transmitter device EM ₁ can comprise two UWB antennas to have a first active permanent antenna and a second antenna controlled by the switch of the sensor C ₁ .

According to different examples, the sensor associated with or integrated in the transmitter device EM1 can be of different types.

According to a first example, it may be a shock sensor. The shock triggers a switch beyond a certain acceleration. This switch can for example be locked mechanically. It can be activated by breaking a vial containing a conductive liquid or by an armed spring blade which is triggered beyond an acceleration and remains blocked in a stable final state.

According to a second example, it may be a tread wear sensor. In this case, the switch opens when the tread containing a thread is worn. This may for example be an HS tire.

According to a third example, it may be an expiry sensor. In this case, it may be a vial with a chemical reagent which is activated when the transmitter device EM ₁ is installed. The reagent reacts for a long period, for example by migration on a substrate. When the reagent reaches the end of its migration or its reaction, it touches a conductive part or inhibits conduction and acts as a switch.

According to a fourth example, it may be a sensor detecting a break in the cold chain. A part composed of a frozen liquid spreads in the event of a break in the cold chain. The flowing liquid then initiates, or inhibits, conduction for the switch.

According to a fifth example, it may be a pressure sensor. In this case, a mechanical part engages and remains locked if a high or low pressure threshold is exceeded.

According to a sixth example, it may be a sensor comprising a seal indicator, such as an indicator of the opening of a package or an object. In this case, a self-adhesive strip contains a closed track connected to the transmitter device EM ₁ . This strip is stuck on the package or on an object at the level of its opening. If the seal is cut or torn off, the track is open and the switch is then in the open position.

According to a seventh example, it may be a humidity sensor. A pad becomes conductive, or degrades and becomes non-conductive, in the presence of moisture within a threshold time. We then know if a package or an object has been wet or exposed to excessive humidity.

According to an eighth example, it may be a usage counter. In this case, a mechanical device is actuated by a small feeler/lever. Each time it is activated, it activates a toothed wheel like that of car speedometers, for example old-fashioned cars. When the wheel has finished counting its maximum, the switch opens or closes. The invention then makes it possible to know whether a cycle of use has been exceeded when the UWB message comprising this data is received by a reception beacon.

According to a ninth example, it may be a tear-out detection sensor. In this case, a sensor triggers the opening or closing of a switch permanently if it is torn from the support. This mode can be, for example, integrated on a fire extinguisher if the pin is pulled out.

According to a tenth example, a radio transmitter device EM ₁ is integrated on a mask, for example, when it takes the form of a small wafer. When the mask has been worn long enough, the sensor C ₁ triggers a modification of a physical state, for example by detecting a humidity threshold. Such a mask makes it possible to locate infected people or to know when the mask has expired. According to one embodiment, the detection of an expired mask makes it possible to grant or deny access to a given zone.

According to one embodiment, the sensor comprises a physical mechanism implementing a manual reset system to reuse the transmitter device EM ₁ subsequently.

According to one embodiment, when the change of state is a change of chemical state, the sensor comprises a removable part representing a consumable which can be replaced. The transmitter device EM ₁ can then be retained in order to be reassociated with a new consumable.

Example of realization of a UWB radio transmitter device

A UWB radio transmitter device may comprise an electronic medium comprising a modulator and a UWB antenna. The radio transmitter device transmits messages in the form of sequences of ultra-wideband radio pulses, known as “UWB messages”. Such UWB messages, formed by a sequence of radio pulses, are also referred to as “Ultra Wide Band-Impulse Radio” or UWB-IR in Anglo-Saxon literature. The transmitter device of the invention can be likened to a radio tag when it is intended to be affixed or fixed to an object in order to be located.

The UWB transmitter device includes a modulator and an antenna for transmitting a signal in the UWB band. The data is modulated by the modulator. According to one embodiment, a memory and a computer can be integrated into the radio transmitter device to process, store and format the data to be transmitted in the messages or the UWB signals.

According to an exemplary embodiment, the UWB radio transmitter device comprises a power supply in order to supply a voltage to the various components. According to another embodiment, the power supply comes from a capacitor which is charged thanks to the reception and collection of radio waves, for example in the UHF band.

According to one embodiment, the UWB radio transmitter device comprises a control module configured to control the transmissions of UWB messages. According to one embodiment, the transmission period, the transmission power, the data coding, the UWB modulation, etc. are configured in the control module to perform UWB message transmissions. According to one example, an accumulated energy threshold makes it possible to trigger the transmission of a UWB message. According to one embodiment, the different functions listed can be supported by different components or be implemented by the same component.

According to an exemplary embodiment, the UWB radio transmitter device comprises a radio reception module for receiving a stream of radio waves. In this embodiment, a transmitter beacon of a radio stream allows the UWB radio transmitter device to collect radio frequency energy.

According to one embodiment, a transmitter beacon of a radio stream can be one or more wireless power supply stations distributed over the geographical area covered by the UWB reception beacons. In this embodiment, the wireless power supply stations remotely supply the tags 20 with electrical energy. According to one embodiment, the transmitting beacons, also called “wireless power supply stations” or UHF generator, are distinct from the receiving beacons. Nothing however excludes, according to other examples, having one or more of said wireless power supply stations which are integrated in one or more UWB receiving beacons, so that at least one piece of equipment of said estimation system station is both a wireless power station and a receiving beacon.

According to the embodiment, the UWB transmitter device comprises a rectifier for converting the spectral power received by the radio reception module into an electric voltage or current. The converted energy can then be stored in an electric accumulator, such as a capacitor. The electric accumulator therefore behaves like a battery making it possible to deliver the energy necessary for the transmission of UWB messages. According to one example, the capacitor can be controlled electrically from an electrical instruction generated by component or directly by itself when a charge level is reached.

According to one embodiment, the transmitter device of the invention could also power a sensor and/or a computer, for example a microprocessor, which interface with the UWB modulator.

According to one embodiment, the UWB radio transmitter device comprises a simplex communication module. By "simplex", we mean that the communication module is suitable only for sending UWB messages but does not allow receiving UWB messages sent by other third-party equipment.

According to one example, the simplex communication module is for example in the form of an electrical circuit comprising equipment such as an antenna, an amplifier, a local oscillator, a mixer, an analog filter and any other equipment that can contribute to transmission of UWB signals.

According to one example, the simplex communication module is configured to transmit the UWB messages in a frequency band centered on 4 gigahertz (GHz) and/or centered on 7.25 GHz. However, nothing excludes considering frequency bands centered on other frequencies.

UWB messages, transmitted in the form of radio signals, present at a given instant an instantaneous frequency spectrum of predetermined width, for example between 500 megahertz (MHz) and 2.5 GHz, which corresponds to radio pulses of durations respectively between a few nanoseconds and a few tenths of a nanosecond.

In one embodiment, the simplex communication module is configured to transmit the UWB messages using an all or nothing radio pulse modulation (“On Off Keying” or OOK in the English literature) to encode bits at emit. That is to say, the values of the bits to be transmitted are encoded by the presence or absence of a radio pulse. For example, if at a given moment the bit to be transmitted is "1" then the simplex communication module transmits a radio pulse, whereas if the bit to be transmitted is "0" said simplex communication module does not transmit a pulse. radio. Such arrangements are advantageous in that they make it possible to reduce the electrical consumption necessary to transmit a UWB message, since the transmission of bits to be transmitted at “0” consumes almost no electrical energy.

According to another embodiment, a position modulation of radio pulses (“Pulse Position Modulation” or PPM in the Anglo-Saxon literature) can be implemented in the method of the invention. For example, considering that the bits to be transmitted in the form of radio pulses are clocked at a predetermined period Tc, then at each period Tc, the pulses are transmitted with an offset relative to the period Tc, the value of said offset depending the value of the bit to send.

According to one embodiment, each ultra-wideband radio pulse can be formed by multiplying a sinusoidal signal by a pulse envelope. In this case, the local oscillator forming the sinusoidal signal corresponding to the carrier frequency of the radio pulses can remain activated continuously over the duration of the UWB message, and the amplitude of said sinusoidal signal is modulated by said pulse envelope. Apart from the instants of emission of radio pulses, the amplitude of the sinusoidal signal is modulated by a signal of zero value.

The modulated signal obtained after amplitude modulation of the sinusoidal signal is then provided at the input of the amplifier, which can also remain activated for the entire duration of the UWB message to be transmitted. By modulating the sinusoidal signal by a pulse envelope before amplifying, the radio pulses are formed before the amplifier. Said amplifier therefore no longer forms the radio pulses but merely amplifies said previously formed radio pulses. It should be noted that it is nevertheless possible to deactivate the amplifier between the radio pulses in order to reduce the power consumption of the amplifier.

According to one embodiment, the control module comprises one or more processors and storage means (magnetic hard disk, electronic memory, optical disk, etc.) in which a computer program product is stored, in the form of a set of program code instructions to be executed.

Alternatively or in addition, the control module comprises one or more programmable logic circuits (FPGA, PLD, etc.), and/or one or more specialized integrated circuits (ASIC).

According to one embodiment, the control module includes a set of means configured in software (specific computer program product) and/or hardware (FPGA, PLD, ASIC, discrete electronic components, etc.).

In order to reconstruct the position of a transmitter device, the server comprises means for performing:

• A consistency check between each message received by a plurality of reception beacons, the consistency corresponding to a difference in arrival time of the messages below a predefined threshold and;
• A construction of the position of a transmitting device by a trilateration algorithm between the arrival times of the different UWB messages.

Such a method is based on the exploitation of the different flight times of the UWB messages transmitted by a transmitting device and received by each receiving beacon.

In order to implement such an algorithm, according to one example, the system comprises a device for transmitting a clock which broadcasts synchronization data to the various reception beacons. Each beacon B ₁ , B ₂ , B ₃ receives a synchronization signal coming for example from another system or from a “master” beacon. The synchronization signal is, for example, a signal comprising a time marker distributed to each beacon, said signal being generated from a remote clock.

According to one embodiment, each beacon includes a computer for:

• extracting at least one identification data item from said radio tag;
• calculating time information timestamping the reception of a message transmitted by the transmitter device, said time marker being generated from a clock and a synchronization message. In the latter case, each beacon comprises, for example, an interface for receiving said synchronization signal.

Claims (9)

UWB radio transmitter device (EM ₁ ) comprising a UWB radio transmitter module and a UHF radio receiver module for collecting signals in order to electrically supply the UWB transmitter module, characterized in that said UWB tag comprises a sensor of state of a physical property of an element of said sensor (C ₁ ), a change of state of said physical property of the element (ELT ₁ ) leading to a modification of an electrical state of an electrical interface (I /O ₁ ) of said sensor (C ₁ ), the emission of a UWB signal comprising the emission of a datum corresponding to the electrical state of the electrical interface (I/O ₁ ). Transmitter device (EM ₁ ) according to claim 1, characterized in that the modification of the state of the physical property passively affects the electrical conductivity of a physical region of the sensor (C ₁ ), said physical region forming an interface of said transmitter device (EM ₁ ) and being connected to the read inputs of a transmitter device electronic chip (EM ₁ ), the transmission of a UWB signal comprising the reading of the electrical state of said electrical interfaces and the transmission of a datum corresponding to said electrical state. Transmitter device (EM ₁ ) according to claim 1, characterized in that the transmission is carried out from the energy collected by the UHF radio reception module. Transmitter device (EM ₁ ) according to claim 1, characterized in that the data transmitted further comprises an identifier stored in a memory of the transmitter device (EM ₁ ) and data characterizing the type of sensor. Transmitter device (EM ₁ ) according to Claim 1, characterized in that the modification of the state of the physical property relates to a modification of a chemical property of a material, to a modification of the conductivity of a zone of said sensor (C ₁ ), to a modification of the mechanical state of an area of said sensor (C ₁ ). Transmitter device (EM ₁ ) according to one of Claims 2 and 5, characterized in that the modification of the conductivity of a zone of the said sensor (C ₁ ) corresponds to a modification of the voltage, the impedance of the said zone . Transmitter device (EM ₁ ) according to Claim 1, characterized in that the sensor is made removable from the transmitter device (EM ₁ ) Transmitter device (EM ₁ ) according to claim 1, characterized in that when sufficient energy is collected by the UHF radio wave reception module, the UWB transmission module automatically reads the value of the physical state of the sensor and automatically sends a UWB message comprising said datum. Transmitting device (EM₁) according to claim 1, characterized in that the sensor is one of the set of the following sensors:

• a shock sensor comprising an accelerometer;
• a tread;
• a mechanical witness of a seal;
• a container of a chemical reagent;
• a sensor comprising a thermofusible material;
• a pressure sensor;
• a humidity sensor comprising a pellet whose conductivity is modified when the humidity of said pellet exceeds a threshold;
• a usage counter;
• a pull-out detector.