JP2018125726A - Search device and communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the time until mountain victims are discovered, by increasing the possibility of discovering the mountain victims compared with conventional one.SOLUTION: A search device 1A receives satellite signals and measures the current position of the own machine upon receiving a satellite reception start instruction from a user (period 331), and transmits a response confirmation signal containing satellite reception instruction information, in a sixth period 314-3. Upon receiving the response confirmation signal, a searched device 2A receives the satellite signals and measures the current position of the own machine (period 341). Upon completion of measurement of the current position, the searched device 2A transmits a response signal containing the positional information of the own machine, in fourth period 322-5. The search device 1A calculates the distance and direction of the searched device 2A from the position of the own machine and the position of the searched device 2A, and displays the identification information of the searched device 2A and the information about the distance and direction of the searched device 2A on the screen of a display 12.SELECTED DRAWING: Figure 15

Description

  The present invention relates to a search device for searching for another communication device (searched device), and a communication system including the search device and the searched device.

  There is a radio beacon system that informs the rescuer who carries a receiver by transmitting a radio wave (a small transmitter) carried by the climber when a climber is lost due to an avalanche. (Patent Document 1, Patent Document 2, Non-Patent Document 1, etc.).

  In this radio beacon system, the transmission device transmits 457 kHz radio waves as a rescue signal, and the reception device can know the direction and approximate distance of the transmission device from the received radio waves.

  In addition, in order to facilitate the search when it is missing, a supervisor holds a terminal device equipped with a GPS (Global Positioning System) function for a child or an elderly person, and a search target person ( 2. Description of the Related Art A system that acquires position information of a terminal device holder) and displays the position information on a map to grasp the position of a search target person is known (see, for example, Patent Document 3). The GPS function measures the position (latitude, longitude) of the own device based on the GPS signal received from the GPS satellite.

JP 2003-198389 A JP 2005-229449 A JP-A-8-65413

Report on the study of advanced beacon system for searching for mountain victims (March 2005 Study session on advanced beacon system for searching for mountain victims)

  However, since the radio beacon system uses a medium-frequency band (457 kHz) and the transmission output is limited to a minute power range due to restrictions based on the Radio Law, the radio wave reception distance is about 100 m at the maximum. It cannot be searched if the distance between them is more than that.

  In addition, the system that displays the position of the search target person on the map makes it difficult to grasp the position of the search target person in environments such as mountains and sea where there are no landmarks such as buildings or roads. . In addition, this type of system requires the installation of a base station, which requires running costs (communication costs).

  In addition, the radio beacon system device and the terminal device that communicates with the base station consume a large amount of battery, so it is difficult to use continuously for a long period of time, and there is a limit to miniaturization and weight reduction.

  The object of the present invention has been made in view of the above points, and in comparison with conventional ones, the possibility of finding a search target person in an environment such as in the mountains or at sea is increased, and until it is discovered. To provide a search device and a communication system capable of reducing time.

  The search device of the present invention is a portable search device that performs direct wireless communication with a portable search target device, and includes a positioning unit that measures the position of its own device using a signal from a satellite, and the search target Based on the receiving means for receiving a signal including the position information of the searched device from the device, the distance between the own device and the searched device based on the position of the own device and the position of the searched device, and the own device And a control unit that estimates the direction of the device to be searched as viewed from the viewpoint and displays information on the estimated distance and direction.

  The communication system of the present invention is a communication system that includes a portable search device and a portable search device that performs wireless communication with the search device, and the search device is connected to the search target device. On the other hand, a first transmission means for transmitting an instruction signal instructing reception of a signal from a satellite, a first positioning means for measuring the position of the own device using a signal from the satellite, Based on the first receiving means for receiving a signal including position information of the searched device, the position of the own device and the position of the searched device, and the distance between the own device and the searched device and the own device First control means for estimating a direction of the searched device and displaying information on the estimated distance and direction, wherein the searched device receives the instruction signal from the searching device. And receiving the instruction signal After comprises a second positioning means for measuring a signal of its own position using the satellite, the second transmission means for transmitting a signal including location information of its own, and a configuration.

  According to the present invention, it is possible to increase the possibility of finding a search target person in an environment such as in the mountains or the sea, and to shorten the time until discovery.

1 is an external view of a search device according to Embodiment 1 of the present invention. 1 is an external view of a search target device according to Embodiment 1 of the present invention. The block diagram which shows the structure of the search device which concerns on Embodiment 1 of this invention. The block diagram which shows the structure of the to-be-searched apparatus which concerns on Embodiment 1 of this invention. The sequence diagram which shows the mode of communication with the search device which concerns on Embodiment 1 of this invention, and a to-be-searched device. The sequence diagram which shows the mode of communication with the search device which concerns on Embodiment 1 of this invention, and a to-be-searched device. Diagram showing the relationship between distance and received signal strength The figure which shows the directivity formed by the search device which concerns on Embodiment 1 of this invention. The figure which shows the information table stored in the memory part of the search device which concerns on Embodiment 1 of this invention. The figure which shows the display screen of the search device which concerns on Embodiment 1 of this invention. The flowchart which shows the flow of operation | movement of the search device which concerns on Embodiment 1 of this invention. The flowchart which shows the flow of operation | movement of the search device which concerns on Embodiment 1 of this invention. The flowchart which shows the flow of operation | movement of the to-be-searched apparatus which concerns on Embodiment 1 of this invention. The block diagram which shows the structure of the search device which concerns on Embodiment 2 of this invention. The block diagram which shows the structure of the to-be-searched apparatus which concerns on Embodiment 2 of this invention. The sequence diagram which shows the mode of communication with the search device and search target device concerning Embodiment 2 of this invention The figure which shows the display screen of the search device which concerns on Embodiment 2 of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
The communication system according to Embodiment 1 of the present invention includes a search device 1 (see FIGS. 1 and 3) and one or a plurality of search target devices 2 (see FIGS. 2 and 4). The search device 1 performs wireless communication with each search target device 2. The search device 1 has all the functions of the search target device 2 and can perform wireless communication with other search devices as the search target device.

[Communication mode]
Search device 1 of this embodiment performs one of the following communication modes based on a user's instruction.
(1) Individual search mode (2) Full search mode (3) Group search mode (4) Searched mode

  (1) In the individual search mode, the search device 1 performs wireless communication with the single searched device 2 instructed by the user, and estimates the relative position (distance and direction) of the single searched device 2. Mode. Note that the search device 1 can register the search target device 2 in advance in association with a registration number (for example, 1 to 10).

  (2) The all search mode is a mode in which the search device 1 requests transmission of response signals for all the search target devices 2 and specifies the search target devices 2 that can receive the response signals and communicate with each other.

  (3) In the group search mode, the search device 1 requests transmission of a response signal to all the search target devices 2 registered in advance, and receives the response signal to identify the searchable device 2 that can communicate. Mode.

  (4) The search mode is a mode in which the search device 1 performs wireless communication with another search device as the search target device.

[Structure of search device 1]
First, the structure of the search device 1 will be described with reference to FIG. FIG. 1 is an external view of a search device 1 according to the present embodiment. 1A is a front view, FIG. 1B is a right side view, FIG. 1C is a rear view, and FIG. 1D is a cross-sectional view along AA.

  The search device 1 has a size (for example, width W: 64 mm, height H: 107 mm, thickness T: 13 mm) and weight (for example, 70 g) that a user (general person) can carry.

  The casing 11 of the search device 1 has a substantially rectangular shape and is formed of a non-conductive member. The front surface 11a of the housing 11 has a flat plate shape. A display unit 12 and an operation unit 13 are provided on the front surface 11 a of the housing 11.

  The display unit 12 is provided on the front surface 11a of the housing 11, and has a screen configured by, for example, an LCD (Liquid Crystal Display). The display screen in each communication mode will be described later.

  The operation unit 13 is provided in the vicinity of the bottom surface 11b side (lower end side) on the front surface 11a of the housing 11 and has a plurality of buttons. The operation unit 13 converts the button operation content based on the user's will into an electric signal and transmits it to a CPU (Central Processing Unit) 131 (see FIG. 3).

  The side surfaces 11c and 11d of the housing 11 are thinner on the flat surface 11e side (upper end side) than the bottom surface 11b (lower end side) with the central portion as a boundary. A power switch 14 is provided on the right side surface 11c.

  A substrate 15 is housed inside the housing 11. The antenna 101 is patterned on the plane 11e side (upper end side) from the center of the substrate 15. Various circuits (see FIG. 3) are placed on the substrate 15.

  The antenna 101 includes a first antenna element 111 serving as a radiator at the center, and a second antenna element 112 and a third antenna element 113 each serving as a director or a reflector on both sides thereof.

  The length of the first antenna element 111 is ¼ (λ / 4) of the wavelength λ. For example, when the search device 1 performs wireless communication using 920 MHz, the length (λ / 4) of the first antenna element 111 is about 81.5 mm. The lengths of the second antenna element 112 and the third antenna element 113 are the same and are slightly shorter than the first antenna element 111.

  Each antenna element 111, 112, 113 is formed in a folded pattern so as to be accommodated in a space of length H1 (for example, 40 mm), and is patterned on both surfaces of the substrate 15 and connected in a through hole.

  A recess 16 is provided at the center of the back surface 11 f of the housing 11. When the user holds the search device 1 so that the user can press the button of the operation unit 13 with the first finger (thumb), the user can stabilize the search device 1 by placing the second finger (index finger) in the recess 16. Can have.

[Structure of searched device 2]
Next, the structure of the search target device 2 will be described with reference to FIG. FIG. 2 is an external view (front view) of the search target device 2 according to the present embodiment.

  The search target device 2 has a size (for example, width W: 40 mm, height H: 63 mm, thickness T: 13 mm) and weight (for example, 20 g) that can be carried by a user (general person).

  The casing 21 of the search device 2 has a substantially square shape and is formed of a non-conductive member. An LED (Light Emitting Diode) 22 and a power switch 23 are provided on the front surface 21 a of the housing 21.

  The LED 22 emits light (flashes) at a predetermined timing, for example, when a radio wave is received from the search device 1 in the individual search mode.

  An antenna (see FIG. 4) and a substrate (not shown) are housed inside the housing 21. Various circuits (see FIG. 4) are placed on the substrate.

  On the plane (upper end) of the housing 21, a convex portion 24 having a hole 24a for passing a string or the like is provided. By tying the string passed through the hole 24a to the user's clothes (such as a belt), the searched device 2 does not leave the user even when the user is in an avalanche or the like.

[Circuit Configuration of Searching Device 1 (Block Diagram)]
Next, the circuit configuration of the search device 1 will be described with reference to FIG. FIG. 3 is a block diagram showing a configuration of search device 1 according to the present embodiment. The search device 1 includes a housing 11 (not shown in FIG. 3), a display unit 12, an operation unit 13, a power switch 14 (not shown in FIG. 3), and a substrate 15 (not shown in FIG. 3). ), The antenna 101, the wireless unit 102, the control unit 103, the ringing unit 104, and the battery 105. The wireless unit 102 and the control unit 103 are placed on the substrate 15.

  The wireless unit 102 processes a wireless signal. The wireless unit 102 includes a transmission unit 121, a reception unit 122, a wireless control unit 123, a first clock 124, a first switch 125, a second switch 126, and a third switch 127.

  The transmission unit 121 performs radio transmission processing such as modulation, amplification, and up-conversion on the baseband digital signal output from the CPU 131 and transmits the radio signal from the first antenna element 111. The frequency of the radio wave (call signal or the like) transmitted from the transmission unit 121 is 710 MHz or more and 960 MHz or less.

  The reception unit 122 performs wireless reception processing such as amplification, down-conversion, and demodulation on the wireless signal received by the first antenna element 111 and outputs a baseband digital signal to the CPU 131. In addition, the reception unit 122 measures a received signal strength indicator (RSSI) of a radio wave received by the first antenna element 111 and outputs a measurement value (analog value) to the radio control unit 123.

  The wireless control unit 123 controls each unit in the wireless unit 102 using the clock signal of the first clock 124. In addition, the wireless control unit 123 converts the measurement value of the received signal strength output from the receiving unit 122 into a digital value and outputs the digital value to the CPU 131. Details of the control performed by the wireless control unit 123 for the switches 125, 126, and 127 will be described later.

  The first clock 124 is a high-speed and high-accuracy clock, and generates a reference clock signal having a predetermined frequency (for example, 36 MHz) for use inside the wireless unit 102.

  The first switch 125 connects either the transmission unit 121 or the reception unit 122 and the first antenna element 111 in accordance with an instruction from the radio control unit 123. The second switch 126 connects / disconnects between the substrate 15 and the second antenna element 112 in accordance with an instruction from the wireless control unit 123. The third switch 127 connects / disconnects between the substrate 15 and the third antenna element 113 in accordance with an instruction from the wireless control unit 123.

  The control unit 103 performs baseband signal processing. The control unit 103 includes a CPU 131, a memory unit 132, a second clock 133, a third clock 134, and a logical operation unit 135.

  The CPU 131 is a central processing unit of the control unit 103 and executes various programs using the memory unit 132 as a work memory. In particular, the CPU 131 generates a signal to be transmitted to the search target device 2, and when the radio wave is received from the search target device 2, the CPU 131 displays the acquired predetermined information on the display unit 12, and the ringing unit 104 notifies the notification sound. Is output.

  The memory unit 132 includes a ROM (Read Only Memory) and a RAM (Random Access Memory), and stores various programs executed by the CPU 131 and various data.

  The second clock 133 is a low-speed clock, and generates a reference clock signal having a predetermined frequency (for example, 32 kHz) for use inside the control unit 103 in a standby state or the like. The third clock 134 is a high-speed and high-accuracy clock, and generates a reference clock signal having a predetermined frequency (for example, 40 MHz) for use inside the control unit 103 in a communication state with the search target device 2 or the like.

  The logical operation unit 135 cooperates with the CPU 131 to determine the difference between the transmission timing of the transmission frame and the reference clock of the third clock 134, the difference between the reception timing of the reception frame and the reference clock of the third clock 134, Based on the difference between the transmission timing of the transmission frame and the reference clock of the third clock 234 (see FIG. 4) and the difference between the reception timing of the reception frame and the reference clock of the third clock 234 in the search device 2 The propagation delay time of the transmission line between 2 is calculated.

  The ringing unit 104 outputs a notification sound from the speaker at a predetermined timing, for example, when receiving an instruction from the user.

  The battery 105 is housed in the housing 11, and supplies power to each part of the search device 1 when a user turns on the power via the power switch 14.

[Function of CPU 131]
Next, functions of the CPU 131 of the search device 1 will be described with reference to FIG. The CPU 131 includes a signal generation unit 131a, a signal acquisition unit 131b, a distance estimation unit 131c, and a direction estimation unit 131d as functions according to the present invention.

  The signal generation unit 131a generates a digital signal sequence (transmission frame) including various types of information based on a user instruction (electrical signal input from the operation unit 13) and outputs the digital signal sequence (transmission frame) to the transmission unit 121. In the individual search mode, the signal generation unit 131a includes the identification information of the single searched device 2 and the identification information of the own device instructed by the user in the digital signal. In the all search mode, the signal generation unit 131a includes, in the digital signal, information indicating that all of the search target devices 2 request transmission of response signals. In the group search mode, the signal generation unit 131a includes identification information of all search target devices 2 belonging to the group instructed by the user in the digital signal. In the search mode, when the signal generation unit 131a inputs information requesting transmission of identification information of its own device from the signal acquisition unit 131b, the signal generation unit 131a receives the identification information of its own device and the identification information of the communication partner searching device 1 as a digital signal. Include in In the individual search mode, the signal generation unit 131a includes, in the digital signal (response confirmation signal), information that instructs the search target device 2 to emit light or output a notification sound based on an instruction from the user. Also good.

  In a communication mode other than the search mode, the signal acquisition unit 131b acquires identification information of the search target device 2 from the digital signal sequence (reception frame) of the received response signal and outputs the identification information to the display unit 12. In the searched mode, the signal acquisition unit 131b acquires information from the digital signal sequence (reception frame) of the received call signal, and when the information requests transmission of identification information of the own device, The fact is output to the signal generator 131a. In the all search mode, the signal acquisition unit 131b is based on the user's instruction, and (1) only the one having the highest received signal strength among the acquired identification information of the search target device 2 is registered (2). Any one of (3) that matches the existing identification information may be output to the display unit 12.

  The distance estimation unit 131c estimates the distance to the search target device 2 based on the received signal strength of the radio wave measured by the reception unit 122 or the propagation delay time calculated by the logic operation unit 135 in the individual search mode. The estimated value is output to the display unit 12. Details of the distance estimation in the present embodiment will be described later.

  The direction estimation unit 131d receives the received signal strength when the second switch 126 is ON and the third switch 127 is OFF and the reception when the second switch 126 is OFF and the third switch 127 is ON in the individual search mode. Based on the signal strength, the direction of the search target device 2 is estimated, and the estimated value is output to the display unit 12. Details of direction estimation in the present embodiment will be described later.

[Circuit Configuration of Searched Device 2 (Block Diagram)]
Next, the circuit configuration of the search target device 2 will be described with reference to FIG. FIG. 4 is a block diagram showing a configuration of searched device 2 according to the present embodiment. The searched device 2 includes a housing 21 (not shown in FIG. 4), an LED 22, a power switch 23 (not shown in FIG. 4), a substrate (not shown), an antenna 201, and a wireless unit 202. And a control unit 203, a ringing unit 204, and a battery 205.

  The radio unit 202 processes radio signals. The wireless unit 202 includes a transmission unit 221, a reception unit 222, a wireless control unit 223, a first clock 224, and a first switch 225.

  The transmission unit 221 performs radio transmission processing such as modulation, amplification, and up-conversion on the baseband digital signal output from the CPU 231, and transmits a radio signal from the antenna 201. The frequency of the radio wave (response signal or the like) transmitted from the transmission unit 221 is 710 MHz or more and 960 MHz or less.

  The reception unit 222 performs wireless reception processing such as amplification, down-conversion, and demodulation on the wireless signal received by the antenna 201 and outputs a baseband digital signal to the CPU 231.

  The wireless control unit 223 controls each unit in the wireless unit 202 using the clock signal of the first clock 224.

  The first clock 224 is a high-speed and high-accuracy clock, and generates a reference clock signal having a predetermined frequency (for example, 36 MHz) for use inside the wireless unit 202.

  The first switch 225 connects either the transmission unit 221 or the reception unit 222 and the antenna 201 in accordance with an instruction from the wireless control unit 223.

  The control unit 203 performs baseband signal processing. The control unit 203 includes a CPU 231, a memory unit 232, a second clock 233, and a third clock 234.

  The CPU 231 is a central processing unit of the control unit 203 and executes various programs using the memory unit 232 as a work memory. In particular, the CPU 231 generates a signal to be transmitted to the search device 1, and causes the LED 22 to emit light when the radio wave is received from the search device 1 or when an instruction is received from the search device 1. Is output.

  The memory unit 232 includes a ROM (Read Only Memory) and a RAM (Random Access Memory), and stores various programs executed by the CPU 231 and various data.

  The second clock 233 is a low-speed clock, and generates a reference clock signal having a predetermined frequency (for example, 32 kHz) to be used inside the control unit 203 in a standby state or the like. The third clock 234 is a high-speed and high-accuracy clock, and generates a reference clock signal having a predetermined frequency (for example, 40 MHz) to be used inside the control unit 203 in a communication state with the search device 1 or the like.

  The ringing unit 204 outputs a notification sound from the speaker at a predetermined timing, for example, when a radio wave is received from the search device 1.

  The battery 205 is housed in the housing 21, and supplies power to each part of the search target device 2 when a user turns on the power via the power switch 23.

[Function of CPU 231]
Next, functions of the CPU 231 of the search target device 2 will be described with reference to FIG. The CPU 231 includes a signal generation unit 231a and a signal acquisition unit 231b as functions according to the present invention.

  When the signal generation unit 231a receives information requesting transmission of its own identification information from the signal acquisition unit 231b, the signal generation unit 231a includes a digital signal sequence (transmission frame) including the identification information of the own device and the identification information of the search device 1 of the communication partner ) And output to the transmission unit 221.

  The signal acquisition unit 231b acquires information from the digital signal sequence (reception frame) of the received call signal, and if the information requests transmission of identification information of the own device, generates a signal to that effect. To the unit 231a. Further, the signal acquisition unit 231 b causes the LED 22 to emit light and output a notification sound from the ringing unit 204 when receiving radio waves from the search device 1 or receiving an instruction from the search device 1.

[Communication sequence in individual search mode]
Next, communication in the individual search mode between search device 1 and search target device 2 according to the present embodiment will be described using the sequence diagram of FIG.

  After the power is turned on, the search device 1 is in a standby state until an instruction from the user (button operation of the operation unit 13) is received. In the standby state, power is not supplied to each unit of the search device 1 in order to reduce power consumption (sleep state). However, power is supplied from the battery 105 to the operation unit 13 and the second clock 133. The second clock 133 always counts by operating a low-speed clock circuit.

  The searched device 2 enters a standby state after being powered on. In the standby state, power is not supplied to each unit of the searchee device 2 in order to reduce power consumption (sleep state). However, power is supplied from the battery 205 to the second clock 233. The second clock 233 always counts by operating a low-speed clock circuit.

  The searchee device 2 supplies power to each unit at each first interval (for example, 3 s) until the count value of the second clock 233 expires (starting state). In the activated state, the searchee device 2 performs reception processing in the first period 321 (for example, 3 ms). At this time, the first clock 224 performs a count operation by operating the clock circuit.

  Then, in the first period 321, the searchee device 2 returns to the sleep state when the information requesting transmission of the identification information of the own device cannot be acquired.

  In the standby state, when the search apparatus 1 is instructed by the user to identify the search target apparatus 2 to be searched (search instruction), the search apparatus 1 supplies power to each unit and starts searching for the search target apparatus 2 (search state). ). At this time, the first clock 124 and the third clock 134 perform a counting operation by operating a high-speed clock circuit.

  The search device 1 that has entered the search state first performs reception processing in the second period 311 (for example, 5 ms) in order to confirm that the other search devices 1 are not transmitting radio waves. Then, when the search device 1 does not receive the radio wave from the other search device 1 during the second period 311, the search device 1 in the third period 312 (for example, 3.5 s) longer than the first interval. The call signal including the identification information, the identification information of the search target device 2 to be searched, and the timing information indicating the transmission timing of the response signal to the search target device 2 is repeatedly transmitted.

  The searched device 2 starts communication with the search device 1 (communication state) when receiving the calling signal during any of the first periods 321-3. At this time, the third clock 234 performs a count operation by operating a high-speed clock circuit. Then, in the fourth period 322-1 (for example, 2 ms) designated by the timing information included in the call signal, the searched device 2 detects its own identification information, identification information of the communication partner searching device 1, and distance information ( A response signal including the difference between the transmission timing of the transmission frame and the reference clock of the third clock 234 and the difference between the reception timing of the reception frame and the reference clock of the third clock 234 (in the following description, the call signal is received) Then, the first response signal to be transmitted is referred to as “call response signal”).

  The search device 1 performs reception processing in the fifth period 313 (for example, 100 ms). Then, as soon as the search device 1 receives the call response signal, in the sixth period 314-1 (for example, 2 ms), the response confirmation signal including the identification information of the own device and the identification information of the search target device 2 to be searched. Send. Note that the radio frequency of the response confirmation signal is different from that of the call signal. Therefore, even if the searched device 2 receives the response confirmation signal and the calling signal from the other searching device 1 at the same time, no interference occurs.

  The searched device 2 performs reception processing in a seventh period 323-1 (for example, 3 ms) immediately after the fourth period 322-1. And the to-be-searched apparatus 2 will transmit a response signal again in the 4th period 322-2 after the 2nd space | interval (for example, 100 ms) shorter than a 1st interval will pass, if a response confirmation signal is received.

  Thereafter, the communication system repeats transmission / reception of response signals and transmission / reception of response confirmation signals until a disconnection instruction is received from the user. Each time the search device 1 receives a response signal, the search device 1 estimates the distance and direction of the search target device 2 using the response signal, and obtains identification information of the search target device 2 and information on the distance and direction of the search target device 2. It is displayed on the screen of the display unit 12.

  When there is a disconnection instruction from the user, in the next sixth period 314-7, the search device 1 disconnects its own identification information, identification information of the search target device 2 to be searched, and the search target device 2. A disconnection signal including information for transmitting is transmitted.

  When the searchee device 2 receives the disconnection signal in the corresponding seventh period 323-7, in the next fourth period 322-8, the searchee device 2 receives the identification information of the own device, the identification information of the communication partner search device 1, and the disconnection signal. A disconnection response signal including information indicating that it has been received is transmitted.

  In the next sixth period 314-8, search device 1 transmits a disconnection confirmation signal including its own identification information, identification information of search target device 2 to be searched, and information indicating that a disconnection response signal has been received. Return to the standby state. In addition, when the searchee device 2 receives the disconnection confirmation signal in the next seventh period 323-8, the searchee device 2 returns to the standby state.

[Communication sequence in full search (group search) mode]
Next, the state of communication in the individual search mode between search device 1 and search target device 2 according to the present embodiment will be described using the sequence diagram of FIG. Note that the sequence of the group search mode is the same as that of the full search mode. In addition, since the states of the search device 1 and the search target device 2 in the standby state are the same in all communication modes and have already been described with reference to FIG. 5, description thereof is omitted here.

  In FIG. 6, it is assumed that there are four search target devices 2 (2-1, 2-2, 2-3, 2-4) in a range where radio waves of the search device 1 reach.

  In the all search mode, the search device 1 in the communication state first performs reception processing in the second period 311 (for example, 5 ms) in order to confirm that the other search devices 1 are not transmitting radio waves. Then, when the search device 1 does not receive radio waves from the other search devices 1 during the second period 311, the search device 1 performs all the coverage in the third period 312 (for example, 3.5 s) longer than the first interval. The calling signal including information requesting the search device 2 to transmit identification information is repeatedly transmitted.

  When each search target device 2 receives a call signal during any of the first periods 321-12, 321-22, 321-31, and 321-41, the first interval time from the start of the first period 321 is received. In a fourth period 322 after the elapse, a call response signal including identification information of the own device is transmitted.

  After the expiration of the third period 312, the search device 1 receives the call response signal in a fifth period 313 (for example, 3.5 s) longer than the first interval.

  Thereafter, the communication system repeats transmission / reception of the paging signal and transmission / reception of the paging response signal for a predetermined number N. The search device 1 displays the identification information of the search target device 2 included in the received call response signal on the screen of the display unit 12. Thereafter, the searching device 1 and each searched device 2 return to the standby state.

[Distance estimation]
Next, a method for estimating the distance to the search target device 2 by the search device 1 according to the present embodiment will be described. As a distance estimation method in the field of wireless communication, a first distance estimation method based on received signal strength and a second distance estimation method based on propagation delay time are known.

  FIG. 7 is a diagram illustrating the relationship between distance and received signal strength. In FIG. 7, the horizontal axis represents distance (m), and the vertical axis represents received signal strength (dBm). As shown in FIG. 7, there is a correlation between the distance and the received signal strength, and the longer the distance, the lower the received signal strength. The first distance estimation method is a method of estimating a distance using a correlation between this distance and the received signal strength.

  Here, as shown in FIG. 7, the longer the distance is, the smaller the fluctuation amount of the received signal strength with respect to the unit distance is. Therefore, when the distance to the search target device 2 is short, the search device 1 can estimate the distance with high accuracy by using the first distance estimation method. On the other hand, when the distance to the search target device 2 is long, the radio wave fluctuation becomes gentle. Therefore, when the first distance estimation method is used, the distance cannot be estimated with high accuracy.

  The second distance estimation method is a method for estimating the distance by multiplying the calculated propagation delay time by the speed of the radio wave. The estimation accuracy of the second distance estimation method is substantially constant regardless of the distance. In addition, when the distance to the search target device 2 is long, higher estimation accuracy is not required than when the distance is short.

  In view of the above points, the distance estimation unit 131c of the search device 1 according to the present embodiment receives signals when the measured received signal strength is greater than a predetermined threshold (for example, −50 dBm) (short-distance mode). The distance to the search target device 2 is estimated using the first distance estimation method based on the signal strength, and the search target is searched using the second distance estimation method based on the propagation delay time when it is equal to or less than a predetermined threshold (wide area mode). The distance to the device 2 is estimated.

  In the present embodiment, hysteresis control is used to switch the estimation method, the first threshold for switching from the first distance estimation method to the second distance estimation method, and the second distance estimation method to the first distance estimation method. A second threshold value (> first threshold value) for switching may be set. As a result, it is possible to prevent the estimated distance from greatly changing in a short time due to frequent switching of the estimation method.

  Further, in the present embodiment, switching from the first distance estimation method to the second distance estimation method is performed based on the magnitude relationship between the received signal strength and the third threshold value, and the second distance estimation method to the first distance estimation method. Switching to may be performed based on the magnitude relationship between the propagation delay time and the fourth threshold value.

[Antenna control and direction estimation]
Next, a method for controlling the antenna 101 by the search device 1 and a method for estimating the direction of the search target device 2 according to the present embodiment will be described.

  When receiving the radio wave (response signal), the radio control unit 123 controls the first switch 125 to connect the first antenna element 111 and the receiving unit 122.

  In the individual search mode, the wireless control unit 123 turns on the second switch 126 and connects the substrate 15 and the second antenna element 112 in the first partial period during the reception period of the radio wave (response signal). Then, the third switch 127 is turned OFF to disconnect between the substrate 15 and the third antenna element 113.

  By this control, the connected second antenna element 112 and substrate 15 are longer than the first antenna element 111 (radiator) as a whole, and thus act as a reflector. Moreover, since the 3rd antenna element 113 becomes shorter than the 1st antenna element 111 (radiator), it acts as a waveguide.

  As a result, the first reception directivity 801 in FIG. 8 is formed in the first partial period. At this time, if the user holds the search device 1 substantially horizontally with the plane 11e side (upper end side) in front, the search device 1 can strongly receive radio waves from diagonally forward right.

  In addition, the wireless control unit 123 turns off the second switch 126 and disconnects the substrate 15 from the second antenna element 112 in the second partial period during the reception period of the radio wave (response signal), and the third switch 127 is turned on to connect between the substrate 15 and the third antenna element 113.

  By this control, the connected third antenna element 113 and substrate 15 are longer than the first antenna element 111 (radiator) as a whole, and thus act as a reflector. Moreover, since the 2nd antenna element 112 becomes shorter than the 1st antenna element 111 (radiator), it acts as a waveguide.

  As a result, the second reception directivity 802 in FIG. 8 is formed in the second partial period. At this time, if the user holds the search device 1 substantially horizontally with the plane 11e side (upper end side) in front, the search device 1 can strongly receive radio waves from the diagonally left front.

  When the search target device 2 to be searched exists on the right side of the user, the received signal strength in the first partial period is higher than the received signal strength in the second partial period. Conversely, when the search target device 2 to be searched exists on the left side of the user, the received signal strength in the first partial period is lower than the received signal strength in the second partial period.

  Therefore, according to the present embodiment, the direction of searched device 2 can be estimated from the magnitude and magnitude relationship of the difference in received signal strength between the first partial period and the second partial period.

  Note that the radio control unit 123 turns off the second switch 126 and the third switch 127 during radio wave transmission in the individual search mode, in the full search mode, in the group search mode, and in the searched mode, and the search device 1 is omnidirectional. Sexual transmission / reception may be performed.

  In the present embodiment, as shown in FIG. 9, the memory unit 132 stores an information table indicating an estimated direction based on the magnitude of the difference in received signal strength and its sign (magnitude relationship). The direction estimation unit 131d estimates the direction of the search target device 2 with reference to the information table of FIG. 9 from the received signal strengths measured in the first partial period and the second partial period, and calculates the estimation result. Output to the display unit 12.

  Note that the direction estimation unit 131d may estimate the direction of the search target device 2 using a plurality of measured values of received signal strength. Thereby, the influence of the fluctuation | variation of a propagation path can be absorbed. “Using a plurality of measured values of received signal strength” means, for example, averaging a plurality of received signal strengths for each directivity (simple moving average, weighted moving average, etc.) and using the average value.

[Display screen]
Next, information displayed on the screen of the search device according to the present embodiment will be described with reference to FIG.

  FIG. 10A is a screen at the time of starting the individual search mode when starting the search for the already-searched apparatus 2 that has already been registered. On this screen, an identification number (identification information) 1001 of the search target device 2 to be searched is displayed together with the registration number. When the user instructs search execution in this display state, the search apparatus 1 executes the individual search mode for the search target apparatus 2 whose identification number is displayed on the screen.

  FIG. 10B is a screen at the start of the individual search mode when starting the search for the unregistered search target device 2. This screen displays a portion 1002 in which the input of the identification number (identification information) of the search target device 2 to be searched is completed. When the user instructs the search execution in this display state after completing the input of the identification number, the search device 1 executes the individual search mode (see FIG. 5) for the searched device 2 whose identification number is displayed on the screen. .

  FIG. 10C is a screen at the start of the full search mode. On this screen, a character 1003 of “ALL” is displayed. When the user instructs search execution in this display state, the search device 1 executes the all-in-one search mode (see FIG. 6).

  FIG. 10D is a screen at the start of the group search mode. On this screen, a character 1004 of “registration ALL” is displayed. When the user instructs search execution in this display state, the search device 1 executes the group search mode (see FIG. 6) for all the search target devices 2 registered in advance.

  FIG. 10E is a screen when the individual search mode is executed and a response signal is received from the searchee device 2. This screen shows the identification information 1005-1 of the searched device 2 that has responded, the information 1005-2 about the distance to the searched device 2, the information 1005-3 about the direction of the searched device 2, and the received signal strength. Information 1005-4 and the like are displayed on the screen.

  In the present embodiment, the update of the information 1005-3 regarding the direction of the searchee device 2 is limited to one step at a time. For example, when the previous direction estimation result is 75 ° left and the next direction estimation result is 30 ° right, the screen approaches from the left 75 ° to 30 ° right by one step (15 °). Information indicating the left 60 ° is displayed. Thereafter, when the direction estimation result is continuously 30 ° to the right, information indicating 45 ° left, 30 ° left 15 ° left, 0 °, 15 ° right, and 30 ° right is sequentially displayed on the screen. Is done. Thereby, the influence of the temporary and rapid fluctuation | variation of the estimated direction by radio wave interruption etc. can be absorbed. In addition, the directivity of FIG. 8 varies depending on the user's way of holding the search device 1 and the like, and the direction estimated from the received signal strength and the actual direction of the search target device 2 do not necessarily match. The direction estimation of the form can roughly estimate the direction of the search target device 2 and is sufficiently effective.

  FIG. 10F is a screen when the full search mode or the group search mode is executed and a call response signal is received from the searchee device 2. On this screen, identification information 1006 of all searched devices 2 to be searched is displayed on the screen. At this time, the identification information 1006 of the search target device 2 is displayed from the top in descending order of the received signal strength.

[Description of flow]
Next, the flow of the operation of search device 1 according to the present embodiment will be described using FIG. 11A and FIG. 11B.

  Search device 1 enters a sleep state when power is turned on (ST1101), and waits for an instruction from the user in this state (ST1102).

  When the instruction from the user is the individual search mode (ST1102: individual search mode), the search device 1 transmits a call signal to the search target device 2 (ST1103, ST1104). Then, search device 1 performs reception processing at the timing instructed to searched device 2 in the call signal (ST1105).

  If the call response signal cannot be received in ST1105 (ST1106: NO), search device 1 repeats the steps from ST1104 to ST1106 (ST1107: NO, ST1108). If the call response signal is not received even if the call signal is transmitted M times (ST1107: YES), search device 1 displays a message indicating that there is no response on the screen of display unit 12 (ST1109). Then, the flow proceeds to ST1132.

  If the call response signal can be received in ST1105 (ST1106: YES), search device 1 immediately transmits a response confirmation signal to searched device 2 (ST1110). Search device 1 measures the received signal strength of the response signal (ST1111), estimates the distance to search target device 2 (ST1112), and estimates the direction of search target device 2 (ST1113). Then, search device 1 displays the identification information of search target device 2 and the information related to the distance and direction of search target device 2 on the screen of display unit 12 (ST1114).

  After that, if there is no instruction to end the search from the user (ST1115: NO) and the timer does not end after counting a predetermined time (ST1116: NO), the search device 1 performs the receiving process again at a predetermined interval ( ST1117).

  When the response signal cannot be received in ST1117 (ST1118: NO), search device 1 repeats steps ST1115 to ST1117. On the other hand, if a response signal can be received in ST1117 (ST1118: YES), the flow returns to ST1110, and search device 1 repeats the steps from ST1110 to ST1117 (communication state).

  In this communication state, when the user gives an instruction to end the search (ST1115: YES), or when the timer ends by measuring a predetermined time (ST1116: YES), the search device 1 transmits a disconnection signal, A disconnection signal reception and disconnection confirmation signal transmission disconnection process is performed (ST1119). Then, the flow proceeds to ST1132.

  In ST1102, when the instruction from the user is the full search mode or the group search mode (ST1102: full search mode, group search mode), search device 1 is registered for all search target devices 2 or in advance. Call signals are transmitted to all the searched devices 2 all at once (ST1121, ST1122), and reception processing is performed over a predetermined period (ST1123). Searching apparatus 1 repeats steps ST1122 and ST1123 N times (ST1124, ST1125).

  When no response signal has been received in N times of ST1123 (ST1126: NO), search device 1 displays a message indicating that there is no response on screen of display unit 12 (ST1127). ). Then, the flow proceeds to ST1132.

  If even one response signal can be received in N times of ST1123 (ST1126: YES), searching device 1 displays the identification information of searched device 2 on the screen of display unit 12 (ST1128).

  After that, if there is no instruction to shift to the individual search mode or an instruction to end the search from the user (ST1129: NO, ST1130: NO), and the timer does not end after measuring a predetermined time (ST1131: NO), search device 1 Repeats step ST1128.

  If there is an instruction to shift to the individual search mode after ST1128 (ST1129: YES), the flow proceeds to ST1103. If the search is instructed by the user (ST1130: YES), or if the timer expires after measuring a predetermined time (ST1131: YES), the flow proceeds to ST1132.

  If the power is not turned off in ST1132, (ST1132: NO), the flow returns to ST1101. On the other hand, if the power is turned off in ST1132 (ST1132: YES), the flow ends.

  In ST1102, when the instruction from the user is the search mode (ST1102: search mode), the flow proceeds to ST1201 in FIG. 12, and search device 1 operates as the search target device.

  Next, the flow of operation of the searchee device 2 according to the present embodiment will be described using FIG.

  The searchee device 2 enters a sleep state when the power is turned on (ST1201), and performs reception processing periodically (at the first interval) (ST1202).

  If the call signal cannot be received in ST1202 (ST1203: NO), searched device 2 returns to the sleep state of ST1201.

  When a call signal can be received in ST1202 (ST1203: YES), searched device 2 transmits a response signal to search device 1 at a designated timing (ST1204), and immediately performs reception processing (ST1205). .

  If a response confirmation signal can be received in ST1205 (ST1206: YES), searched device 2 transmits a response signal again to searching device 1 after a predetermined time (second interval) has passed (ST1204). Thereafter, when a response confirmation signal can be received (ST1206: YES), steps ST1204 and ST1205 are repeated.

  If no response confirmation signal is received in ST1205 (ST1206: NO) and a disconnection signal is received (ST1207: YES), searched device 2 performs a disconnection process of disconnection response signal transmission and disconnection confirmation signal reception (ST1208). . Then, the flow proceeds to ST1209.

  If neither a response confirmation signal nor a disconnection signal is received in ST1205 (ST1206: NO, ST1207: NO), the flow proceeds to ST1209.

  If the power is not turned off in ST1209 (ST1209: NO), the flow returns to ST1201. On the other hand, if the power is turned off in ST1209 (ST1209: YES), the flow ends.

[effect]
As described above, according to the present embodiment, the searched device 2 does not always need to transmit a periodic signal such as a beacon, and only receives a response signal when receiving a call signal from the searching device 1. Since transmission is sufficient, power consumption is reduced as compared to conventional devices. Therefore, the searched device 2 can continuously operate for a long period (for example, three months or more), and the battery runs out until the user descends even if the user turns on the power in advance such as when entering the mountain. There is no worry. Furthermore, if the search target device 2 is turned on in advance, the search target device 2 can perform wireless communication with the search device 1 without further user operation, so that the user is in an avalanche or the like. Even if the user loses his or her mind, the search device 1 can specify the position of the search target device 2.

  In addition, since the search device 1 and the search target device 2 perform wireless communication using a frequency of 710 MHz or more and 960 MHz or less, the searchable device 2 has a long radio wave receivable distance from the search device 1. A wide range (for example, 100 m to 5 km) can be searched. If a higher frequency is used like 2.4 GHz of WLAN, the antenna becomes shorter and the receivable distance becomes shorter. Further, when a higher frequency is used, the straightness of radio waves becomes stronger and the wraparound is reduced, so that the possibility of finding a search target person such as a victim in an environment where there is an obstacle is reduced. On the other hand, if a lower frequency is used, the antenna becomes longer and the device becomes larger.

  Further, by using the distance estimation method of the present embodiment, the search device 1 can accurately estimate the relative distance to the search target device 2 when the search target device 2 exists at a short distance. When the searched device 2 does not exist at a short distance, the relative distance to the searched device 2 can be estimated with a predetermined accuracy.

  Further, by using the antenna structure and switching control of the present embodiment, the circuit scale of the antenna portion can be reduced and the entire apparatus can be reduced in size and weight as compared with the case of using an array antenna. In the first antenna element 111 (radiator) that receives radio waves, switching for switching directivity is not performed, so that switching loss is minimized. Further, since the switching timing of the second switch 126 and the third switch 127 is the same, there is only one control system for switching the switch.

  Further, by providing the recess 16 at the center of the back surface 11f of the casing 11 of the search device 1 of the present embodiment, the user can press the button of the operation unit 13 with the first finger (thumb). When the search device 1 is held in the hand, the search device 1 can be stably held by placing the second finger (index finger) in the recess 16. Also, this way of holding can prevent the influence of the antenna directivity and stabilize the direction estimation accuracy because hands and fingers do not come around the antenna elements 111, 112, and 113.

  In addition, when the searched device 2 of the present embodiment receives radio waves from the searching device 1 or receives an instruction from the searching device 1, the LED 22 is caused to emit light and the sounding unit 204 outputs a notification sound. The user of the search device 1 can search the search target device 2 by his / her own visual or auditory sense.

  And according to this Embodiment, by said effect, possibility that a search subject person, such as a mountain victim, will be discovered more, and it can be anticipated that time until it is discovered is shortened more.

  In the above embodiment, a case has been described in which the search target device 2 always transmits a call response signal when receiving the call signal from the search device 1 in the full search mode or the group search mode. The search target device 2 stores the identification information of the predetermined search device 1 in advance, and when the call signal from the search device 1 is received, the search target device 2 stores the call information in the stored identification information of the search device 1. The paging response signal may be transmitted only when there is a match with the identification information of the search device 1 included in the signal.

  Thereby, the search device 1 can display only the identification information of the searched device 2 in which the identification information of the own device is registered. In addition, since the number of times of transmitting the call response signal is relatively reduced, the searched device 2 can suppress power consumption.

  Moreover, although the said embodiment demonstrated the case where the information regarding the estimated distance and direction of the to-be-searched apparatus 2 was displayed on screens, such as LCD of the search apparatus 1, this invention is not limited to this, The search apparatus 1 Other display methods may be used such as providing a plurality of LEDs on the front surface of the housing 11 and changing the position of the LED to emit light according to the distance and direction of the search target device 2.

  In the above embodiment, the case where the identification information of the search target device 2 is displayed on the screen of the search device 1 has been described. However, the present invention is not limited to this. For example, the search device 1 includes a speaker, The identification information of the search target device 2 may be output by voice from a speaker.

  Moreover, although the said embodiment demonstrated the case where the recessed part 16 was provided in the center part of the back surface 11f of the housing | casing 11 of the search device 1 in order to prevent affecting antenna directivity, this invention is not limited to this. However, a hand or a finger may be prevented from coming around the antenna elements 111, 112, and 113 by another configuration, such as providing a convex portion on the flat surface 11e side (upper end side) slightly from the center of the back surface 11f. .

(Embodiment 2)
In the second embodiment of the present invention, a communication system in which a search device and a search target device perform long-distance wireless communication in order to specify the position of a search target person far away (for example, 1 km or more) will be described.

  The communication system according to the present embodiment includes a search device 1A and one or a plurality of search target devices 2A. The search device 1A performs long-distance wireless communication with each search target device 2A by using a communication technique of an LPWA (Low Power Wide Area) network defined by IEEE802.15 / 4k or the like. By using the LPWA network communication technology (hereinafter referred to as “LPWA communication”), the searching device 1A and the searched device 2A can perform long-distance wireless communication without increasing the power consumption.

  Further, each of search device 1A and each searched device 2A receives a signal (hereinafter referred to as “satellite signal”) from an artificial satellite (not shown) of GNSS (Global Navigation Satellite System). GNSS is a general term for satellite navigation systems having performance (accuracy and reliability) that can be used for civil air navigation such as GPS, GLONASS, and Galileo.

  The structure of the search device 1A is the same as the structure of the search device 1 shown in FIG. The structure of the searched device 2A is the same as the structure of the searched device 2 shown in FIG.

[Circuit Configuration of Searching Device 1A (Block Diagram)]
Next, the circuit configuration of the search device 1A will be described with reference to FIG. FIG. 13 is a block diagram showing a configuration of search apparatus 1A according to the present embodiment. In the configuration of the search device 1A shown in FIG. 13, the same reference numerals as those in FIG. 3 are assigned to portions common to the configuration of the search device 1 shown in FIG. 3, and detailed description thereof is omitted.

  The search apparatus 1A shown in FIG. 13 has a configuration in which a satellite antenna 151 is added to the search apparatus 1 shown in FIG. 3 and a satellite receiver 161 is added in the radio unit 102. Further, a new function is added to the CPU 131A of the search device 1A shown in FIG. 13 with respect to the CPU 131 of the search device 1 shown in FIG. In addition, in order to perform LPWA communication, a spreading process is added to the wireless transmission process performed by the transmission unit 121 of the search apparatus 1A, and a despreading process is added to the wireless reception process performed by the reception unit 122 of the search apparatus 1A. The In addition, a function for starting the satellite reception unit 161 is added to the wireless control unit 123 of the search device 1A.

  When receiving a satellite reception activation instruction from the user via the CPU 131A, the wireless control unit 123 activates the satellite reception unit 161. On the other hand, when receiving a satellite reception stop instruction from the user via the CPU 131A, the wireless control unit 123 stops the satellite reception unit 161.

  The satellite antenna 151 receives radio waves (satellite signals) having a predetermined frequency (1.5 GHz band) from the satellite.

  The satellite reception unit 162 performs radio reception processing such as amplification, down-conversion, demodulation, etc. on radio waves (satellite signals) received from the satellite antenna 151 in accordance with the activation instruction of the radio control unit 123, and performs baseband processing. Are output to the CPU 131A.

[Function of CPU 131A]
Next, functions of the CPU 131A of the search device 1A will be described with reference to FIG. In the CPU 131A shown in FIG. 13, a positioning unit 131e is added to the CPU 131 shown in FIG. Further, the signal generation unit 131a, the signal acquisition unit 131b, the distance estimation unit 131c, and the direction estimation unit 131d of the CPU 131A (FIG. 13) of the present embodiment have functions of the CPU 131 (FIG. 3) described in the first embodiment. Other new functions are added.

  The positioning unit 131e measures the current position (longitude, latitude) of its own device (search device 1A) based on the baseband digital signal of the satellite signal output from the satellite receiving unit 162 in the individual search mode, Is output to the distance estimation unit 131c and the direction estimation unit 131d.

  When receiving the satellite reception activation instruction from the user in the individual search mode, the signal generation unit 131a includes the identification information of the search target device 2A, the identification information of the own device, and the satellite reception instruction information in the digital signal (transmission frame). Further, in the individual search mode, the signal generation unit 131a, when receiving a satellite reception disconnection instruction from the user, converts the identification information of the search target device 2A, the identification information of the own device, and the satellite reception disconnection information into a digital signal (transmission frame). include.

  The signal acquisition unit 131b acquires the position information of the search target device 2A from the digital signal (reception frame) of the received response signal, and outputs the position information to the distance estimation unit 131c and the direction estimation unit 131d.

  In the individual search mode, the distance estimation unit 131c, when receiving a satellite reception activation instruction from the user, based on the position information of the own apparatus and the position information of the searched apparatus 2A, the distance from the own apparatus to the searched apparatus 2A And the estimated distance value is output to the display unit 12.

  When receiving a satellite reception activation instruction from the user in the individual search mode, the direction estimation unit 131d determines the direction of the searched device 2A relative to the own device based on the position information of the own device and the position information of the searched device 2A. The estimated value of the direction is output to the display unit 12.

[Circuit Configuration of Searched Device 2A (Block Diagram)]
Next, the circuit configuration of the search target device 2A will be described with reference to FIG. FIG. 14 is a block diagram showing a configuration of searched device 2A according to the present embodiment. In the configuration of the searchee device 2A shown in FIG. 14, the same reference numerals as those in FIG. 4 are given to the portions common to the configuration of the searchee device 2 shown in FIG.

  14A has a configuration in which a satellite antenna 251 is added to the search target device 2 illustrated in FIG. 4 and a satellite reception unit 261 is added in the wireless unit 202. Further, a new function is added to the CPU 231A of the searchee device 2A shown in FIG. 14 with respect to the CPU 231 of the searchee device 2 shown in FIG. In addition, a spreading process is added to the wireless transmission process performed by the transmission unit 221 of the searched device 2A, and a despreading process is added to the wireless receiving process performed by the receiving unit 222 of the searched device 2A. In addition, a function for starting the satellite reception unit 261 is added to the wireless control unit 223 of the searchee device 2A.

  When receiving a satellite reception activation instruction from the CPU 231A (signal acquisition unit 231b), the wireless control unit 223 activates the satellite reception unit 261. On the other hand, when receiving a satellite reception stop instruction from the user via the CPU 231A, the wireless control unit 223 stops the satellite reception unit 261.

  The satellite antenna 251 receives radio waves (satellite signals) having a predetermined frequency (1.5 GHz band) from the satellite.

  The satellite reception unit 261 performs radio reception processing such as amplification, down-conversion, and demodulation on radio waves (satellite signals) received from the satellite antenna 251 in accordance with the activation instruction of the radio control unit 223, and performs baseband processing. Are output to the CPU 231A.

[Function of CPU 231A]
Next, functions of the CPU 231A of the searchee device 2A will be described with reference to FIG. In the CPU 231A shown in FIG. 14, a positioning unit 231c is added to the CPU 231 shown in FIG. Further, a new function is added to the signal generation unit 231a and the signal acquisition unit 231b of the CPU 231A (FIG. 14) of the present embodiment in addition to the functions of the CPU 231 (FIG. 4) described in the first embodiment.

  The positioning unit 231c measures the current position (longitude, latitude) of the own device (searched device 2A) based on the baseband digital signal of the satellite signal output from the satellite receiving unit 261, and obtains the position information of the own device. It outputs to the signal generation part 231a.

  When the position information of the own device is input from the positioning unit 231c, the signal generation unit 231a includes the identification information of the own device, the identification information of the communication partner searching device 1A, and the position information of the own device in the digital signal (transmission frame). .

  When the received response signal includes satellite reception instruction information, the signal acquisition unit 231b instructs the radio control unit 223 to start satellite reception. In addition, when the received response signal includes satellite reception disconnection information, the signal acquisition unit 231b instructs the radio control unit 223 to stop satellite reception.

[Communication sequence in individual search mode]
Next, communication in the individual search mode between search device 1A and search target device 2A according to the present embodiment will be described using the sequence diagram of FIG. In the sequence of FIG. 15, operations common to the sequence of FIG. 5 are denoted by the same reference numerals as those in FIG. 5, and detailed description thereof is omitted.

  The operations of search device 1A and searched device 2A in the standby state and search state of the sequence of FIG. 15 are the same as the operations of search device 1 and search target device 2 in the standby state and search state of the sequence of FIG.

  1 A of search apparatuses start communication with to-be-searched apparatus 2A (communication state), will receive a satellite signal start instruction from a user, and will receive a satellite signal and will measure the present position of an own machine now (period 331), in the next sixth period 314-3, a response confirmation signal including its own identification information, identification information of the search target apparatus 2A to be searched, and satellite reception instruction information is transmitted.

  Upon receiving the response confirmation signal including the satellite reception instruction information, the searched device 2A receives the satellite signal and measures the current position of the own device (period 341). Upon completion of the measurement of the current position, the searched device 2A receives a response signal including the identification information of the own device, the identification information of the communication device searching device 1A, and the position information of the own device in the next fourth period 322-i. Send.

  The search device 1A calculates the distance and direction of the searched device 2A from the own device from the position of the own device and the position of the searched device 2A, and the identification information of the searched device 2A and the distance of the searched device 2 and Information on the direction is displayed on the screen of the display unit 12.

  When there is an instruction to disconnect satellite signal reception from the user, search device 1A stops receiving the satellite signal, performs the distance estimation and the direction estimation described in Embodiment 1, and performs the next sixth period 314- In j, a response confirmation signal including the identification information of the own device, the identification information of the search target device 2A to be searched, and the satellite reception disconnection information is transmitted.

  The searched device 2 </ b> A stops receiving the satellite signal when receiving the response signal including the satellite reception disconnection information in the corresponding seventh period 323-6.

  Thereafter, the search device 1A and the search target device 2A perform the same operations as the search device 1 and the search target device 2 described in the sequence of FIG.

  In the sequence of FIG. 15, a case has been described in which the search device 1A starts receiving satellite signals based on a user instruction (manually) and instructs the search target device 2A to start satellite reception. The embodiment is not limited to this, and search device 1A automatically starts receiving satellite signals at the timing when communication with search target device 2A is started, and instructs search target device 2A to start satellite reception. You may do it. Alternatively, the search device 1A first performs the distance estimation described in the first embodiment, and when the distance is greater than or equal to a threshold (for example, 200 m), starts receiving the satellite signal, and the search target device 2A receives the satellite. The start may be instructed to estimate the distance based on the position of the own device and the position of the search target device 2A.

  Further, in the sequence of FIG. 15, a case has been described in which the search device 1A stops receiving satellite signals based on a user instruction (manually) and instructs the search target device 2A to stop satellite reception. The form is not limited to this, and when the distance estimated based on the position of the own device and the position of the search target device 2A falls below a threshold (for example, 200 m), the satellite signal reception is automatically stopped, The distance estimation described in the first embodiment may be performed by instructing the search device 2A to stop satellite reception.

[Display screen]
The display screen of search device 1A of the present embodiment may be the same as the display screen of search device 1 shown in FIG. However, when the distance estimation and the direction estimation are performed based on the positioning result using the satellite signal, the search device 1A performs a screen display different from that shown in FIG. 10 as shown in FIG. May be.

  FIG. 16A is a so-called north-up display screen in which north (N) is displayed on the upper end side of the casing 11 of the search device 1 </ b> A centering on the own device. On this screen, the estimated position 1601-1 of the search target device 2A, information 1601-2 regarding the distance to the search target device 2A, and the like are displayed.

  Note that the search device 1A may be equipped with an orientation sensor, and the orientation sensor may acquire the orientation (absolute direction) of its own device and output it to the display unit 12. In this case, the direction 1601-3 of the own device is displayed on the screen.

  In addition, as shown in FIG. 16B, in the so-called head-up display screen that displays the traveling direction on the upper end side of the casing 11 of the search device 1A, the estimated position 1602-1 of the search target device 2A, the search target device 2A Information about the distance 1602-2, the direction 1602-3 of the own device may be displayed.

[effect]
As described above, according to the present embodiment, by using LPWA communication, the search device 1A and the search target device 2A can perform long-distance wireless communication without increasing power consumption. The searchable time can be extended and the searchable range can be expanded.

  In addition, according to the present embodiment, search device 1A and search target device 2A can measure their own positions based on satellite signal reception, so search device 1A and search target device 2A are far away. Even in the case of being away, the distance and direction of the search target device 2A from the search device 1A can be accurately estimated.

  For example, if the positioning error based on the satellite signal is 100 m, when the distance from the search device 1A to the search target device 2A is 10 km, the distance error is ± 2% and the direction error is ± 1 °. Note that the shorter the distance from the search device 1A to the search target device 2A, the greater the error in the distance and the error in the direction. Therefore, when the distance from the search device 1A to the search target device 2A is equal to or less than the threshold value, It is desirable to switch to the method described in Embodiment 1 and estimate the distance and direction.

  In addition, according to the present embodiment, since the search device 1A can display the distance and direction of the search target device 2A from the own device, the user of the search device 1A can also be used in an environment such as in the mountains or at sea. The position of the search target person can be easily grasped.

  In addition, according to the present embodiment, search device 1A and search target device 2A directly communicate, and search target device 2A can transmit a response signal including its own position information to search device 1A. Therefore, it is not necessary to install a base station or the like in order to acquire the position of the search target device 2A.

  Further, according to the present embodiment, since search device 1A can instruct start / stop of satellite signal reception to search target device 2A, the power consumed by satellite signal reception processing of search target device 2A can be reduced. It is possible to minimize the battery life of the searched device 2A.

[variation]
In the second embodiment, after the search device 1A receives the satellite signal, the search device 1A may transmit information indicating the satellite that has transmitted the satellite signal to the search target device 2A.

  As a result, the searchee device 2A can capture the satellite signal at high speed, and the power consumption can be further reduced.

  In the second embodiment, the case where the search device 1A communicates with the search target device 2A by LPWA communication from the start to the end has been described, but the present invention is not limited to this, and the search device 1A and the search target device The communication with the search target device 2A may be performed by LPWA communication only while the 2A is receiving the satellite signal.

  The present invention is suitable for use in a search device for searching for the position of another communication device, and a communication system including a search device and a searched device.

1, 1A Search device 2, 2A Search target device 11, 21 Case 12 Display unit 13 Operation unit 14, 23 Power switch 15 Substrate 16 Recess 22 LED
101, 201 Antenna 102, 202 Radio section 103, 203 Control section 104, 204 Ring section 105, 205 Battery (power supply section)
111 First antenna element 112 Second antenna element 113 Third antenna element 121, 221 Transmitter 122, 222 Receiver 123, 223 Radio controller 124, 224 First clock 125, 225 First switch 126 Second switch 127 Third Switch 131, 131A, 231, 231A CPU
131a, 231a Signal generation unit 131b, 231b Signal acquisition unit 131c Distance estimation unit 131d Direction estimation unit 131e, 231c Positioning unit 132, 232 Memory unit 133, 233 Second clock 134, 234 Third clock 135 Logic operation unit 151, 251 Satellite Antenna 161, 261 Satellite receiver

Claims (5)

A portable search device that performs direct wireless communication with a portable search target device,
Positioning means for measuring the position of the aircraft using signals from satellites;
Receiving means for receiving a signal including position information of the searched device from the searched device;
Based on the position of the own device and the position of the searched device, the distance between the own device and the searched device and the direction of the searched device viewed from the own device are estimated, and information on the estimated distance and direction Control means for displaying
A search device comprising: Further comprising a transmission means for transmitting an instruction signal for instructing the searched device to receive a signal from a satellite;
The search device according to claim 1. Performs wireless communication with the search target device using LPWA (Low Power Wide Area) network communication technology.
The search device according to claim 1 or 2. A communication system comprising a portable search device and a portable search target device that performs wireless communication with the search device,
The search device includes:
First transmitting means for transmitting an instruction signal for instructing the search target device to receive a signal from a satellite;
First positioning means for measuring the position of the aircraft using a signal from a satellite;
First receiving means for receiving a signal including position information of the searched device from the searched device;
Based on the position of the own device and the position of the searched device, the distance between the own device and the searched device and the direction of the searched device viewed from the own device are estimated, and information on the estimated distance and direction First control means for displaying
Comprising
The searched device is:
Second receiving means for receiving the instruction signal from the search device;
A second positioning means for measuring the position of the aircraft using a signal from a satellite after receiving the instruction signal;
Second transmission means for transmitting a signal including the position information of the own machine;
Comprising
Communications system. The search device and the search target device perform wireless communication using a communication technology of an LPWA (Low Power Wide Area) network.
The communication system according to claim 4.

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