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Title:
METHOD AND WEARABLE ELECTRONIC DEVICE FOR RESCUING A PERSON IN DISTRESS
Document Type and Number:
WIPO Patent Application WO/2021/209921
Kind Code:
A1
Abstract:
The invention relates to a method for rescuing a person in distress, comprising equipping at least a first person with a first wearable electronic device (10a) and a second person with a second wearable electronic device(10b), referred hereafter as the person in distress and the rescuer respectively, each wearable device comprising a processing unit (12a), a memory (12b), a Global Navigation Satellite System-GNSS receiver (16), a Low Power Wide Area Network (LPWAN) transmitter/receiver (14), an antenna (15) adapted to emit and receive a signal through the LPWAN and to receive a signal from the GNSS, a user interface (20) for inputting a distress signal, and a display unit (26) for displaying the location of a person in distress, wherein the processing unit (12a) is configured to execute a software stored in the memory (12b) of the wearable electronic device to turn the electronic device from a standby mode either into a tracking mode for locating and finding a person in distress or into an SOS mode for sending SOS signals. The method further comprises the steps of: a. turning the first wearable device (10a) by the person in distress through its user interface (20) from a standby mode into an SOS mode; b. obtaining the GNSS coordinates of the first wearable electronic device (10a) worn by the person in distress; emitting from the first wearable electronic device (10a), through the LPWAN, one or more SOS signals at a given constant emission power until a first SOS signal is picked up by the second wearable electronic device (10b) worn by the rescuer, and d. processing, by the processing unit (12a) of the second wearable electronic device (10b), at several time intervals, SOS signals sent by the first wearable electronic device and current GNSS coordinates of the second wearable electronic device (10b) to provide guiding information on the display (26) of said second wearable electronic device (10b) as a function of the location of the person in distress and the rescuer as the rescuer moves towards the person in distress.

Inventors:
AESCHIMANN RÉMI (CH)
Application Number:
PCT/IB2021/053075
Publication Date:
October 21, 2021
Filing Date:
April 14, 2021
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
SYNCTECH SA (CH)
International Classes:
G01S19/47; G01S5/00; G01S5/02
Foreign References:
US20180356533A12018-12-13
JP2014027377A2014-02-06
US6222484B12001-04-24
TW201701262A2017-01-01
US6414629B12002-07-02
Attorney, Agent or Firm:
P&TS SA (CH)
Download PDF:
Claims:
CLAIMS

1. Method for rescuing a person in distress, comprising - equipping at least a first person with a first wearable electronic device (10a) and a second person with a second wearable electronic device (10b), referred hereafter as the person in distress and the rescuer respectively, each wearable device comprising a processing unit (12a), a memory (12b), a Global Navigation Satellite System-GNSS receiver (16), a Low Power Wide Area Network (LPWAN) transmitter/receiver (14), an antenna (15) adapted to emit and receive a signal through the LPWAN and to receive a signal from the GNSS, a user interface (20) for inputting a distress signal, and a display unit (26) for displaying the location of a person in distress, wherein the processing unit (12a) is configured to execute a software stored in the memory (12b) of the electronic device to turn the wearable electronic device from a standby mode either into a tracking mode for locating and finding a person in distress or into an SOS mode for sending SOS signals, the method further comprising the steps of: a. turning the first wearable device (10a) by the person in distress through its user interface (20) from a standby mode into an SOS mode, b. obtaining the GNSS coordinates of the first wearable electronic device (10a) worn by the person in distress, c. emitting from the first wearable electronic device (10a), through the LPWAN, one or more SOS signals at a given constant emission power until a first SOS signal is picked up by the second wearable electronic device (10b) worn by the rescuer, wherein each SOS signal sent by the first wearable electronic device (10a) contains the location of the person in distress, and d. processing, by the processing unit (12a) of the second wearable electronic device (10b), at several time intervals, SOS signals sent by the first wearable electronic device and current GNSS coordinates of the second wearable electronic device (10b) to provide guiding information on the display (26) of said second wearable electronic device (10b) as a function of the location of the person in distress and the rescuer as the rescuer moves towards the person in distress, wherein the emission power of said first wearable electronic device (10a) is regulated as a function of the distance between the rescuer and the person in distress, said emission power decreasing as the rescuer moves towards the person in distress.

2. The method for rescuing a person in distress according to claim 1, wherein the first wearable electronic device (10a) turns from the standby mode into the SOS mode when an SOS command is activated by the person in distress through the user interface (20) of the first wearable electronic device (10a).

3. The method for rescuing a person in distress according to any preceding claim, wherein the second wearable electronic device (10b) turns from the standby mode into the tracking mode upon receipt of an SOS signal emitted by the first wearable electronic device (10a).

4. The method for rescuing a person in distress according to claim 3, wherein said second wearable electronic device (10b) is programmed to go more frequently into a listening sate in the tracking mode than in the standby mode.

5. The method for rescuing a person in distress according to any preceding claim, wherein each of said first and second wearable electronic devices (10a, 10b) further comprises an Inertial measurement Unit - IMU (18), and wherein the IMU output is also obtained and processed under step d. together with said SOS signals and GNSS coordinates to provide guiding information to the rescuer.

6. The method for rescuing a person in distress according to any preceding claim, wherein each SOS signal received by the second wearable electronic device (10b) comprises a unique identifier and the location of the person in distress and wherein said unique identifier is processed by the processing unit (12a) of said second electronic wearable device (10b) in order to verify that the SOS signal has been sent by the first wearable electronic device (10a),

7. The method for rescuing a person in distress according to claim 6, wherein an acknowledgement of receipt signal is sent by the second wearable electronic device (10b) to the first wearable electronic device (10a), through the LPWAN, upon successful authentication of said unique identifier, said acknowledgement of receipt signal comprising the location of the rescuer.

8. The method for rescuing a person in distress according to claim 7, wherein the first wearable electronic device (10a) provides location of the rescuer on the display (26) of said first wearable device upon receipt of said acknowledgment of receipt signal.

9. The method for rescuing a person in distress according to claim 8, wherein the first wearable electronic device (10a) sends regularly SOS signals once the SOS command has been activated, the second wearable electronic devices (10b) sending an acknowledgement of receipt signal comprising the location of the rescuer for each SOS signal received from the first wearable electronic device (10a) in order to display the direction and the distance between the rescuer and the person in distress on the display (26) of said first wearable electronic device (10a) as the rescuer moves towards the person in distress.

10. The method for rescuing a person in distress according to any preceding claim, wherein each person from a group of more than two persons, for example from three to ten persons or more, is equipped with a wearable electronic device (10a, 10b, 10c, 10d, 10e) having the same hardware than the first and second wearable electronic devices, and wherein SOS signals sent by one wearable electronic device (10e) are received directly by the other wearable electronic devices (10a, 10b, 10c, 10e), or indirectly through an acknowledgement receipt signal sent by one or more of said other wearable electronic devices upon receipt of said SOS signals.

11. The method for rescuing a person in distress according to claim 10, wherein said acknowledgement receipt signal comprises the location of the person in distress in order to send said location to other wearable electronic devices which have not received any SOS signal or not all SOS signals sent by said one wearable electronic device (10e) of the person in distress.

12. The method for rescuing a person in distress according to any preceding claim, wherein each of the wearable electronic devices (10a, 10b, 10c, 10d, 10e) is a smartwatch.

13. A wearable electronic device (10a, 10b) for rescuing a person in destress comprising a processing unit (12a), a memory (12b), a Global Navigation Satellite System-GNSS receiver (16), a Low Power Wide Area Network-(LPWA) transmitter/receiver (14), an antenna (15) adapted to emit and receive a signal through the LPWA, an Inertial Measurement Unit (18), a user interface (20) for inputting a distress signal, and a display unit (26) for displaying the location of a person in distress and the location of a rescuer, wherein the processing unit (12a) of the wearable electronic device (10a, 10b) is configured to run a software store in the memory (12b) to turn the wearable electronic device (10a, 10b) either into a tracking device for locating and finding a person in distress or into an SOS device for sending SOS signals,

14. The wearable electronic device (10a, 10b) according to claim 13, wherein said electronic device is programmed to turn into an SOS device when an SOS command is activated by a person in distress through the user interface (20).

15. The wearable electronic device (10a, 10b) according to claim 13, wherein said electronic device is programmed to turn into a tracking device upon receipt of:

- an SOS signal containing the location of the person in distress, or

- an acknowledgment of receipt signal sent by another wearable electronic device upon receipt of said SOS signal by said another electronic device.

16. The wearable electronic device (10a, 10b) according to claim 15, wherein said device is programmed to go more frequently into a listening state when said wearable electronic device (10a, 10b) has been turned into a tracking device.

17. The wearable electronic device (10a, 10b) according to any of claims 13 to 16, wherein said device is a smartwatch.

Description:
Method and wearable electronic device for rescuing a person in distress Field of the invention

[0001] The present invention relates to a method and a wearable electronic device which may in particular be used to provide information on location and direction for rescuing a person lost typically at sea or in unfamiliar wooded terrain. The method and the wearable electronic device may also be used to find a lost kid for example in a crowded area.

Description of related art

[0002] Wearable electronic devices configured to provide direction information to a specific location based on the current location of the person wearing the device already exist. [0003] TW20171262, for example, relates to a trip positioning method, in which a master device is carried by a trip leader and a plurality of sub-devices are carried by trip members. When in use, the master device is activated in order to input time and place of gathering through a control module and then transmit the information to the sub-devices. Once the information has been received by the sub-devices, the time for gathering is repetitively compared by a processor in the sub-devices with current time. Once the gathering time is checked, a route indicating information between the current place and the gathering place is provided through a comparison carried out by a GPS module. An e-compass is activated for displaying in a display the direction to the gathering place.

[0004] The above method relies on a master device having a hardware that is different from the hardware of the sub-devices and a sub-device cannot therefore take over the functionalities of the master device and vice- versa which may be needed under some circumstances. Moreover, the master device and sub-devices do not have a function that permits to send and receive a distress signal for locating and rescuing a person in distress. [0005] US 6,414,629 discloses a tracking system that includes a target unit and a locating unit. The target unit comprises a GPS receiver, a signal transmitter to send a signal including a position of the target unit, and a processor to calculate an optimal time interval for transmission of the signal. The locating unit comprises a GPS signal receiver, a compass to provide a reference direction of the locating unit, a signal receiver to receive the signal sent by the transmitter of the target unit, a processor to calculate a range and bearing from the locating unit to the target unit, and an indicator to display the range and bearing.

[0006] As for TW20171262, the tracking system of US 6,414,629 relies on a target unit having a hardware that is different from the hardware of a locating unit. It is therefore essential to equip a person who is at risk of becoming in a distress situation and a person who may act as a rescuer with the right unit which may be difficult to foresee in some circumstances.

[0007] In addition, US 6,414,629 relies on the inertial data from an accelerometer to determine when the target unit is at or near the crest of the wave for determining an optimal time interval for transmission of target position encoded signals from the target unit that are more likely to reach the locating unit. A major inconvenient of US 6,414,629 stems from the fact that the locating unit is highly energy consuming since it is typically powered on at all times and therefore may require an AC power supply or a high- capacity battery leading to a cumbersome or bulky locating unit. [0008] An aim of the present invention is therefore to provide a method for locating and rescuing a person in distress, which can be used typically for a person lost at sea or in unfamiliar wooded terrain, which overcomes the limitation of the prior art. [0009] More particularly, an aim of the present invention is to provide a method for locating and rescuing a person in distress which uses two or more wearable electronic devices that are energy efficient, light and easy to wear.

[0010] Another aim of the present invention is to provide a wearable electronic device, such as a smartwatch, which is adapted to carry out the above method.

Brief summary of the invention

[0011] These aims are achieved by a method for rescuing a person in distress, comprising

- equipping at least a first person with a first wearable electronic device and a second person with a second wearable electronic device, referred hereafter as the person in distress and the rescuer respectively, each wearable device comprising a processing unit, a memory, a Global Navigation Satellite System-GNSS receiver, a Low Power Wide Area Network (LPWAN) transmitter/receiver, an antenna adapted to emit and receive a signal through the LPWAN and to receive a signal from the GNSS, a user interface for inputting a distress signal, and a display unit for displaying the location of a person in distress, wherein the processing unit is configured to run a software stored in the memory of the wearable electronic device to turn the said electronic device from a standby mode either into a tracking mode for locating and finding a person in distress or into an SOS mode for sending SOS signals.

The method further comprises the steps of: a, turning the first wearable device by the person in distress through its user interface from a standby mode into an SOS mode, b. obtaining the GNSS coordinates of the first wearable electronic device worn by the person in distress, c. emitting from the first wearable electronic device, through the LPWAN, one or more SOS signals at a given constant emission power until a first SOS signal is picked up by the second wearable electronic device worn by the rescuer, wherein each SOS signal sent by the first wearable electronic device contains the location of the person in distress, and d. processing, by the processing unit of the second wearable electronic device, at several time intervals, SOS signals sent by the first wearable electronic device and current GNSS coordinates of the second wearable electronic device to provide guiding information on the display of said second wearable electronic device as a function of the location of the person in distress and the rescuer as the rescuer moves towards the person in distress.

The emission power of the first wearable electronic device is regulated as a function of the distance between the rescuer and the person in distress, the emission power decreasing as the rescuer moves towards the person in distress,

[0012] In an embodiment, the first wearable electronic device turns from the standby mode into the SOS mode when an SOS command is activated by the person in distress through the user interface of the first wearable electronic device. [0013] In an embodiment, the second wearable electronic device turns from the standby mode into the tracking mode upon receipt of an SOS signal emitted by the first wearable electronic device. [0014] In an embodiment, the second wearable electronic device is programmed to go more frequently into a listening sate in the tracking mode than in the standby mode.

[0015] In an embodiment, each of said first and second wearable electronic devices further comprises an Inertial measurement Unit - IMU. The IMU output is also obtained and processed under step d. together with said SOS signals and GNSS coordinates to provide guiding information to the rescuer.

[0016] In an embodiment, each SOS signal received by the second wearable electronic device comprises a unique identifier and the location of the person in distress. The unique identifier is processed by the processing unit of the second electronic wearable device in order to verify that the SOS signal has been sent by the first wearable electronic device,

[0017] In an embodiment, an acknowledgement of receipt signal is sent by the second wearable electronic device to the first wearable electronic device, through the LPWAN, upon successful authentication of the unique identifier. The acknowledgement of receipt signal comprises the location of the rescuer.

[0018] In an embodiment, the first wearable electronic device provides location of the rescuer on the display of the first wearable device upon receipt of said acknowledgment of receipt signal,

[0019] In an embodiment, the first wearable electronic device sends regularly SOS signals once the SOS command has been activated. The second wearable electronic device sends an acknowledgement of receipt signal comprising the location of the rescuer for each SOS signal received from the first wearable electronic device in order to display the direction and the distance between the rescuer and the person in distress on the display of said first wearable electronic device as the rescuer moves towards the person in distress.

[0020] In an embodiment, each person from a group of more than two persons, for example from three to ten persons or more, is equipped with a wearable electronic device having the same hardware than the first and second wearable electronic devices. SOS signals sent by one wearable electronic device are received directly by the other wearable electronic devices, or indirectly through an acknowledgement receipt signal sent by one or more of said other wearable electronic devices upon receipt of said SOS signals.

[0021] In an embodiment, said acknowledgement receipt signal comprises the location of the person in distress in order to send said location to other wearable electronic devices which have not received any SOS signal or not all SOS signals sent by the one wearable electronic device of the person in distress.

[0022] In an embodiment, each of the wearable electronic devices is a smartwatch.

[0023] Another aspect of the invention relates to a wearable electronic device for rescuing a person in destress. The wearable electronic device comprises a processing unit, a memory, a Global Navigation Satellite System- GNSS receiver, a Low Power Wide Area Network -(LPWAN) transmitter/ receiver, an antenna adapted to emit and receive a signal through the LPWAN, an Inertial Measurement Unit, a user interface for inputting a distress signal, and a display unit for displaying the location of a person in distress and the location of a rescuer. The processing unit of the wearable electronic device is configured to run a software stored in the memory of the wearable electronic device to turn said wearable electronic device either into a tracking device for locating and finding a person in distress or into an SOS device for sending SOS signals,

[0024] In an embodiment, the electronic device is programmed to turn into an SOS device when an SOS command is activated by a person in distress through the user interface.

[0025] In an embodiment, the wearable electronic device is programmed to turn into a tracking device upon receipt of:

- an SOS signal containing the location of the person in distress, or

- an acknowledgment of receipt signal sent by another wearable electronic device upon receipt of said SOS signal by said another electronic device.

[0026] In an embodiment, the wearable electronic device is programmed to go more frequently into a listening state when the electronic device has been turned into a tracking device. [0027] In an embodiment, the wearable electronic device is a smartwatch.

Brief Description of the Drawings

[0028] The invention will be better understood with the aid of the description of several embodiments given by way of examples and illustrated by the figures, in which: - Figure 1 shows a schematic view of the method according to an embodiment using a smartwatch as a wearable electronic device;

- Figure 2 shows several smartwatches which are configured to communicate through a LPWA network having a MESH topology according to an embodiment; - Figure 3 shows a flow diagram of the different steps of the method for locating a person in destress and for guiding a rescuer to that person according to an embodiment,

- Figure 4 shows a block diagram of a wearable electronic device, e.g. a smartwatch, used to perform the different steps of Figure 3 according to an embodiment ;

Figure 5 shows a functional block flow diagram between two wearable electronic devices, i.e. the wearable electronic device of the person in distress and the wearable electronic device of a rescuer; - Figures 6a to 6d show an example of guiding information on the display of the wearable electronic device worn by a rescuer as he is heading towards the person in distress, and

Figures 7a to 7d show an example of information on the display of the wearable electronic device worn by the person in distress as the rescuer is approaching towards that person.

Detailed Description of several embodiments of the Invention

[0029] With reference to Figures 1-3, the method for rescuing a person in distress is implemented by means of at least two wearables electronic devices 10a, 10b which are preferably in the form of a smartwatch. In most cases, however, the method may be implemented by more than two smartwatches, for example by a group of people, e.g. from three to ten or more, wearing each a smartwatch. As shown in Figure 2, the smartwatches 10a-10e are configured to communicate through a Low Power Wide Area Network (LPWAN) such as LoRaWAN® open standard which enables transmissions with a range exceeding at least 5 km with low power consumption of the smartwatches. [0030] Each of the smartwatches 10a-10e have the same hardware configuration and is programmed to turn either into a tracking device or an SOS device. In the illustrated embodiment of Figure 2, assuming that the smartwatch 10e is worn by a person in distress, it turns into a SOS device when that person activates an SOS command to send a SOS signal. Each of the other smartwatches 10a-10d turn into a tracking device upon receipt of the SOS signal or upon receipt of an acknowledgement receipt signal (AR in Figure 2) sent by one or more of the other smartwatches 10a-10d.

[0031] Accordingly, if some of the persons wearing the smartwatches 10a- 10d do not receive the SOS signal, they will still be able to assist when they intercept an acknowledgement of receipt signal from at least one of the smartwatches 10a-10d that has received the SOS signal. Therefore, the smartwatches 10a-10d communicate with each other through said acknowledgement of receipt signal. Any smartwatch 10a-10e may thus be used interchangeably as a tracker device for locating and finding a person in distress, or as an SOS device for sending a SOS signal to one or more tracker devices.

[0032] Referring to Figures 1 and 3, the method for rescuing a person in distress implies that at least two persons is equipped with a smartwatch 10a, 10b having the same hardware.

[0033] In an embodiment, the method comprises the following steps:

S1 : the person in distress activates an SOS command through a user interface 20 (Figure 4) of his/her smartwatch 10a, That person may for example press a dedicated emergency button 22 for at least 2 or 3 seconds in order to turn the smartwatch 10a from a standby mode to an emergency mode upon activation of the SOS command. S2: the geographical coordinates of the person in distress are obtained using the GPS of his/her smart watch 10a,

S3: an SOS signal is sent by the smartwatch 10a of the person in distress via LPWA technology in peer-to-peer transmission without relying a host computer on a cloud. The SOS signal may contain a unique smartwatch identification number, the position of the person in distress, and a payload such as "SOS", or "I'm tired". The SOS signal may also comprise metadata such as checksum which provides information on the number of bits of the SOS signal, S4: upon receipt of the SOS signal or an acknowledgement of receipt signal by the smartwatch 10b worn by another person (hereafter rescuer), the geographical coordinates and geospatial position of a rescuer are obtained using the GPS and the measurements of an Inertial Measurement Unit 18 of his/her smartwatch. S5: the smartwatch 10b of the rescuer displays on a display unit 26 the direction and distance of the person in distress in reiation to the rescuer,

SS: the smartwatch 10b of the rescuer sends an acknowledgement of receipt signal to the person in distress. The acknowledgement signal may contain a unique smartwatch identification number, the position of the person in distress, and a payload with the position of the rescuer and a command such as "acknowledge" or "rescuer". The acknowledgement of receipt signal may also comprise metadata such as checksum.

[0034] In the illustrated embodiment of Figure 2, the smartwatches 10a-10d have been tuned into a tracker mode while the smartwatch 10e has been turned into an SOS mode for sending an SOS signal to each of the smartwatches 10a-10e. The smartwatch 10e transmits an SOS signal through a decentralized communication system using LPWA, such as as LoRaWAN®. In other words, the different signals are processed by a microcontroller of each smartwatch instead of relying on a host computer.

[0035] With reference to Figure 4, the hardware of each smartwatch comprises a microcontroller 12 comprising a processing unit 12a and a memory 12b, a LPWA receiver 14, a GPS receiver 16, an Inertial Measurement Unit (IMU) 18, preferably a 9-axis IMU, and a user interface 20 (comprising an emergency button 22) which are all electrically connected to the microcontroller 12. An antenna 15 is electrically coupled to the LPWA receiver 14 and the GPS receiver 16. The antenna 15 may be for example 3D MID dual-band antenna. The smartwatch further comprises a display unit 26 and optionally a vibrating motor 24 connected to outputs of the microcontroller 12. A battery 28 is arranged to power all the electric components of the smartwatch.

[0036] The memory 12b of the microcontroller 12 stored a software programmed to turn the smartwatch from a standby mode to an emergency mode when the emergency button 22 has been activated or when it has received an SOS signal or an acknowledgement of receipt signal. When the emergency button has been activated, LPWAN frequencies are set with the maximum authorized duty cycle to ensure connection with a second smartwatch in order to send the GNSS position of the person in distress to a smartwatch of a rescuer.

[0037] When the smartwatch is used as a tracker for locating and finding a person in distress the software is programmed to go more frequently into a listening state for scanning the radio frequency band when the smartwatch is in the emergency mode than when it is in the standby mode. Considering that the listening state consumes much more energy to pick up SOS signals, a compromise must be found on the time spent by the smartwatch in the listening state to increase the chances to pick up an SOS signal or acknowledgement of receipt signal without discharging the battery too fast.

[0038] The software is configured to execute logical operations as shown in the functional block flow diagram illustrated in Figure 5. Once the emergency button 22 has been activated, the microcontroller 12 gets the geographical position of the person in distress using the GPS of his/her smartwatch and sends an SOS signal. The SOS signal received by at least one or several other smartwatches 10a-10d (Figure 2) having the same hardware is checked to determine whether the signal received has been emitted by the smartwatch of the person in distress.

[0039] In that respect, the software generates a unique identifier for each smartwatch and store the identifier in a memory of the microcontroller 12. The identifier is sent along with the SOS signal for authentication of the smartwatch. Upon successful authentication of the signal, the microcontroller 12 of the rescuer smartwatch 10b may trigger an alarm and/or vibrate the smartwatch to alert the rescuer of an emergency and sends an acknowledgment of receipt signal to the smartwatch 10a of the person in distress and to other wearable electronic devices.

[0040] The acknowledgment of receipt signal contains the geographical position of the rescuer in order to display on the display unit of the smartwatch of the person in distress the location of the rescuer with the distance between the rescuer and the person in distress. The acknowledgement of receipt signal also contains the position of the distress person in order to send that information to other wearable electronic devices.

[0041] The microcontroller 12 of the rescuer smartwatch then acquires the geographical coordinates and the geospatial position of the rescuer using the GPS and the measurements of the 9-axis IMU 18 and process the geographical coordinates and the geospatial position of the rescuer together with the SOS signal to display on the display unit 26 of his/her smartwatch the direction and the distance of the person in distress as a function of the location of the person in distress and the rescuer.

[0042] The microcontroller 12 of the rescuer smartwatch regularly acquires up-to-date geographical coordinates and the geospatial position of the rescuer in order to update the direction and the distance between the rescuer and the person in distress on the display 26 as the rescuer is heading towards the person in distress as shown in Figures 6a-6d.

[0043] The emission power of the first wearable electronic device 10a is regulated as a function of the distance between the rescuer and the person in distress and decreases as the rescuer moves towards the person in distress in order to save the battery,

[0044] In an embodiment, the smartwatch 10a of the person in distress sends several SOS signals with his/her geographical position at regular intervals, for example every 10 seconds, so that the microcontroller 12 of the rescuer smartwatch 10b processes at regular intervals, for example every 10 seconds, each received SOS signal together with his/her current geographical coordinates and geospatial position in order to take into consideration any displacement of the person in distress when displaying his/her location on the display of the rescuer smartwatch.

[0045] Likewise, upon receipt of each SOS signal, the microcontroller 12 of the rescuer smartwatch 10b sends an acknowledgement of receipt signal containing the current location of the rescuer so that the display unit 26 of the smartwatch of the person in distress may display the progression of the rescuer as shown in Figures 7a-7d. [0046] The acknowledgement of receipt signal also contains the position of the person in distress so that other devices, too far away to receive the SOS signal, can be informed on the position of the person in distress.

[0047] Various modifications and variations to the described embodiments of the invention will be apparent to those skilled in the art without departing from the scope of the invention as defined in the appended claims. For example, the wearable electronic device may be any electronic portable device which may be carried notably in the pocket of a garment or attached to the waistband of a pair of trousers by means of a fastening clip.

Reference list

Electronic wearable device Smartwatch 10

Microcontroller 12 Processing unit 12a

Memory 12b

LPWA Transmitter/receiver 14 Antenna 15

3D MID dual-band antenna GNSS receiver 16

GPS receiver

Inertial Measurement Unit (IMU) 18 9-axis IMU User interface 20 Emergency button 22

Vibrating motor 24 Display 26 Battery 28

Low Power Wide Area Network (LPWAN)