JP7817697B2 - Data transmission device, data collection device, and data collection system - Google Patents

Description

The present invention relates to technology for retrieving data from devices that store data, such as data loggers.

For example, Patent Document 1 discloses an observation system for collecting observation data from observation equipment. This observation system includes multiple observation equipment installed at observation locations, and a multicopter equipped with power transmission and communication equipment. The multicopter flies autonomously from a base station to above the observation equipment. When the multicopter reaches above the observation equipment, the power transmission and communication equipment supplies power to the observation equipment and collects the observation data from the observation equipment. When the power transmission and communication equipment finishes supplying power and collecting the observation data, the multicopter returns to the base station.

Patent No. 6666663

Patent Document 1 does not specifically disclose how the power transmission and communication equipment and the observation equipment will operate if a communication error occurs between the power transmission and communication equipment and the observation equipment when the power transmission and communication equipment retrieves observation data from the observation equipment.

The object of the present invention is to provide technology for reliable communication when retrieving data.

The data transmission device of the present invention comprises an antenna and a communication unit, wherein the communication unit modulates a reflected wave of an unmodulated signal received by the antenna and transmits a plurality of ordered data blocks in sequence, and when the communication unit has completed transmission of the nth data block and receives an unmodulated signal in a first standby state waiting for the resumption of reception of the unmodulated signal, it transmits data blocks in sequence starting from the n- _ndth data block, where n _d is a predetermined value and is also 0 or a natural number.

The data recovery device of the present invention comprises an antenna, a transmitter, a receiver, and a data recovery control unit. The transmitter transmits an unmodulated signal from the antenna based on instructions from the data recovery control unit. The receiver receives a data block carried on a reflected wave of the unmodulated signal via the antenna, and outputs the received data block if no error is detected in the received data block, or does not output the received data block if an error is detected in the received data block. The data recovery control unit stores the acquired data block if it receives a data block from the receiver within a predetermined period of time, and instructs the transmitter to temporarily stop transmitting the unmodulated signal if it does not receive a data block from the receiver within the predetermined period of time.

The data collection system of the present invention comprises the data transmission device of the present invention and the data collection device of the present invention.

The present invention enables reliable communication when retrieving data.

FIG. 1 is a conceptual diagram of a data collection system 10 according to a first embodiment of the present invention. FIG. 2 is a block diagram of the data collection device 20 according to the first embodiment. FIG. 3 is a block diagram of a data transmission device 30 according to the first embodiment. FIG. 4 is a state transition diagram showing the data collection process of the data collection control unit 24 according to the first embodiment. FIG. 5 is a state transition diagram showing the data transmission process of the communication control unit 36 according to the first embodiment. FIG. 6 is a first example of a timing chart showing the data collection process of the data collection system 10 according to the first embodiment. FIG. 7 is a second example of a timing chart showing the data collection process of the data collection system 10 according to the first embodiment. FIG. 8 is a third example of a timing chart showing the data collection process of the data collection system 10 according to the first embodiment. FIG. 9 is a diagram for explaining how to determine n _d . FIG. 10 is a state transition diagram showing the data transmission process of the communication control unit 36 according to the modified example of the first embodiment. FIG. 11 is an example of a timing chart showing the data collection process of the data collection system 10 according to the modified example of the first embodiment. FIG. 12 is a state transition diagram showing the data transmission process of the communication control unit 36 according to the second embodiment. FIG. 13 is an example of a timing chart showing the data collection process of the data collection system 10 according to the second embodiment. FIG. 14 is a state transition diagram showing the data transmission process of the communication control unit 36 according to the modified example of the second embodiment. FIG. 15 is an example of a timing chart showing the data collection process of the data collection system 10 according to the modified example of the second embodiment.

The following describes several embodiments for implementing the present invention. Each embodiment is an example, and partial substitution or combination of the configurations shown in different embodiments is possible. In each embodiment, differences from those described in previous embodiments will be explained. In particular, similar effects resulting from similar configurations will not be mentioned in each embodiment.

First Embodiment
1 is a conceptual diagram of a data collection system 10 according to a first embodiment of the present invention. The data collection system 10 includes a drone 11, a data collection device 20, an observation device 12, and a data transmission device 30. The data collection device 20 is mounted on the drone 11. The data transmission device 30 is installed near the observation device 12 and communicates with the observation device 12 via wired or wireless communication. The observation device 12 and the data transmission device 30 are installed, for example, at an observation site on the ground.

The drone 11 autonomously flies from a base station (not shown) to the sky above the data transmission device 30, and then hovers above the data transmission device 30. When the drone 11 begins hovering, the data collection device 20 transmits an unmodulated signal to the data transmission device 30. This unmodulated signal is, for example, a microwave. In this specification, microwaves are electromagnetic waves with a frequency of 300 MHz to 300 GHz. The data transmission device 30 wakes up upon receiving the unmodulated signal and transitions from sleep mode to operating mode. The data transmission device 30 then reads the observation data from the observation device 12 and transmits the observation data to the data collection device 20 via backscattering communication. The transmitted data consists of multiple ordered data blocks, and the data blocks are transmitted in order. The data collection device 20 receives and stores the observation data. When the data collection device 20 finishes collecting the observation data, the drone 11 returns to the base station by autonomous flight.

Note that data collection may be performed when the drone 11 has landed, rather than while the drone 11 is hovering.

Figure 2 is a block diagram of the data collection device 20 according to the first embodiment. The data collection device 20 includes antennas 211 and 212, a transmitter 22, a receiver 23, a data collection control unit 24, and a memory unit 25.

The transmitter 22 transmits an unmodulated signal from the antenna 211 based on an instruction from the data collection control unit 24. The transmitter 22 conforms to the standard for specified low-power radio stations established by the Association of Radio Industries and Businesses (ARIB) and performs carrier sense before starting transmission, transmits for a predetermined time or less, and then stops transmission for a predetermined time or more. For example, the transmitter 22 conforms to the standard ARIB STD-T107 for specified low-power radio stations, 920 MHz band mobile unit identification radio equipment, established by the Association of Radio Industries and Businesses. Specifically, the transmitter 22 stops transmitting the unmodulated signal for time _T2 every time _T1 . Furthermore, the transmitter 22 independently stops transmission in accordance with the standard, without following an instruction from the data collection control unit 24.

Note that it is not essential that the transmitter 22 conform to the standard specifications for specific low-power radio stations.

The receiver 23 has an RF circuit, an A/D conversion circuit, and a data processing unit. The RF circuit demodulates the signal received by the antenna 212. The A/D conversion circuit converts the signal extracted by the RF circuit into a digital signal. The data processing unit processes the data contained in the signal output from the A/D conversion circuit. The data processing unit is composed of a CPU, memory, etc., and performs predetermined processing by executing a program.

The receiver 23 receives the data block carried on the reflected wave of the unmodulated signal (i.e., the unmodulated carrier wave) at the antenna 212. The receiver 23 performs error detection on the received data block in its data processing unit. Error detection methods include, for example, checksum, parity check, and CRC. If the receiver 23 does not detect an error in the received data block, it outputs the received data block; if it detects an error in the received data block, it does not output the received data block.

Note that the transmitter 22 and receiver 23 use antennas 211 and 212, respectively, but they may share a single antenna.

The data collection control unit 24 controls the entire data collection device 20. The data collection control unit 24 obtains data blocks in which no errors have been detected from the receiver 23 and stores the data blocks. The data collection control unit 24 also outputs a transmission control signal to the transmitter 22. The data collection control unit 24 commands the transmitter 22 to start transmission by raising the transmission control signal, and commands the transmitter 22 to stop transmission by lowering the transmission control signal. Furthermore, the data collection control unit 24 communicates with the drone 11 as appropriate. The data collection control unit 24 is composed of a CPU, memory, etc., and performs predetermined processing by executing programs.

The data collection control unit 24 temporarily stores the data blocks in its own memory, and after data collection is complete, writes the data blocks to the storage unit 25. The storage unit 25 is a non-volatile memory such as an SD memory card.

Figure 3 is a block diagram of a data transmission device 30 according to the first embodiment. The data transmission device 30 includes an antenna 31 and a communication unit 32. The communication unit 32 includes a rectification modulation circuit 33, a voltage detection circuit 34, a voltage holding circuit 35, and a communication control unit 36.

The rectifying and modulating circuit 33 rectifies and converts the unmodulated signal received by the antenna 31 into a DC voltage and outputs the DC voltage to the voltage detection circuit 34. The rectifying and modulating circuit 33 also modulates the reflected wave of the unmodulated signal received by the antenna 31 by changing the load on the antenna 31 based on the modulating signal ms output from the communication control unit 36.

The voltage detection circuit 34 outputs a voltage V _nms to the voltage holding circuit 35 and the communication control unit 36 in accordance with the output voltage of the rectification modulation circuit 33. When the output voltage of the rectification modulation circuit 33 is higher than the reference voltage, the voltage detection circuit 34 sets the voltage V _nms to a high level, and when the output voltage of the rectification modulation circuit 33 is lower than the reference voltage, the voltage detection circuit 34 sets the voltage V _nms to a low level.

The voltage holding circuit 35 has an RS latch or an RS flip-flop, and has a set terminal S, a reset terminal R, and a power supply terminal F. When the voltage V _nms rises to a high level, that is, when the voltage at the set terminal S rises to a high level, the voltage holding circuit 35 connects the power supply terminal F to a power source (not shown) and maintains this state, thereby supplying power to the communication control unit 36. When the communication control unit 36 raises the voltage at the reset terminal R to a high level, the voltage holding circuit 35 stops the connection between the power supply terminal F and the power source, thereby terminating the power supply to the communication control unit 36.

Note that the voltage holding circuit 35 may also be comprised of other types of latches or flip-flops.

The communication control unit 36 determines the reception status of the unmodulated signal by monitoring the voltage V _nms . That is, when the voltage V _nms is at a high level, the communication control unit 36 determines that an unmodulated signal is being received, and when the voltage V _nms is at a low level, the communication control unit 36 determines that an unmodulated signal is not being received. The communication control unit 36 also reads observation data from the observation device 12 and processes the observation data for transmission. Furthermore, the communication control unit 36 transmits the observation data by outputting a modulated signal ms carrying the observation data to the rectification modulation circuit 33. The communication control unit 36 is composed of a CPU, memory, etc., and performs predetermined processing by executing a program.

When the drone 11 arrives above the data transmission device 30, it notifies the data collection control unit 24 of the data collection device 20 that it has arrived at its destination. Upon receiving this notification, the data collection control unit 24 commands the transmitter 22 to begin transmission. Upon receiving this command, the transmitter 22 begins transmitting an unmodulated signal to the data transmission device 30.

When the antenna 31 of the data transmission device 30 receives the unmodulated signal, the rectifying/modulating circuit 33 outputs a DC voltage, the voltage detecting circuit 34 raises the voltage V _nms to a high level, the voltage holding circuit 35 supplies power to the communication control unit 36, and the communication control unit 36 transitions from sleep mode to operating mode. The communication control unit 36 then reads observation data from the observation device 12, processes the observation data for transmission, and outputs a modulated signal ms to the rectifying/modulating circuit 33, thereby notifying the data collection device 20 that preparations for transmission are complete.

Upon receiving this notification, the data collection control unit 24 of the data collection device 20 commands the transmitter 22 to stop transmission, and then commands the transmitter 22 to start transmission again. After notifying that preparation for transmission is complete, the communication control unit 36 detects a rise in the voltage V _nms and starts transmitting the data block.

The notification that transmission preparation is complete is sent so that the transmission suspension specified in the standard does not occur between the notification of transmission preparation completion and the suspension of transmission caused by that notification.

FIG. 4 is a state transition diagram showing the data collection process of the data collection control unit 24 according to the first embodiment. FIG. 5 is a state transition diagram showing the data transmission process of the communication control unit 36 according to the first embodiment. FIG. 6 is a first example of a timing chart showing the data collection process of the data collection system 10 according to the first embodiment. In the first example shown in FIG. 6, the data collection device 20 and the data transmission device 30 are communicating normally. FIG. 7 is a second example of a timing chart showing the data collection process of the data collection system 10 according to the first embodiment. In the second example shown in FIG. 7, the data collection device 20 detects an error in a data block. FIG. 8 is a third example of a timing chart showing the data collection process of the data collection system 10 according to the first embodiment. In the third example shown in FIG. 8, the power transmitted from the data collection device 20 to the data transmission device 30 temporarily decreases. FIG. 9 is a diagram for explaining how n _d is determined. FIG. 9 shows the period during which each data block is transmitted from the data transmission device 30 to the data collection device 20.

6 to 8, "unmodulated signal" indicates the period during which the transmitter 22 transmits and the period during which the transmitter 22 stops transmitting. The period during which the transmitter 22 performs carrier sense is not shown. "Voltage V _nms " indicates the waveform of the voltage V _nms . "Data transmission" indicates the period during which each data block is transmitted from the data transmitting device 30 to the data collection device 20. "Error detection" indicates the period during which the receiver 23 performs error detection. "Data acquisition" indicates the period during which the data collection control unit 24 acquires and stores the data blocks. "Transmission control signal" indicates the waveform of the transmission control signal.

4, when the data collection control unit 24 receives notification that preparation for transmission is complete and then commands the transmitter 22 to start transmission again, it sets i to 2 and n _sm to 0. i represents the mode. n _sm represents the number of data blocks acquired by the data collection control unit 24 from the start or restart of transmission of the unmodulated signal to the present without stopping the transmission of the unmodulated signal.

The data collection control unit 24 again commands the transmitter 22 to start transmission and then waits for acquisition of a data block (S11, S12). If a data block is acquired within the time T _ad [i] from the transition to state S12, it stores the data block in its own memory and increments the value of n _sm by 1. If n _sm is equal to 1, it sets i to 0 and returns to state S12. If n _sm is equal to N _s , it sets i to 1, sets n _sm to 0 and returns to state S12. Otherwise, it returns to state S12. _{T ad} [0] represents the time the data collection control unit 24 waits for the next data block after acquiring and saving the data block, without stopping transmission of the unmodulated signal. _{T ad} [1] represents the time the data collection control unit 24 waits for the next data block after acquiring and saving the data block, stopping transmission of the unmodulated signal according to the standard. T _ad [2] represents the time it takes for the data collection control unit 24 to wait for a data block after instructing the transmitter 22 to start transmission. N _s represents the number of data blocks that the data collection control unit 24 acquires from the start or restart of unmodulated signal transmission until time T ₁ , assuming that communication is proceeding normally. In other words, N _s represents the number of data blocks that the communication control unit 36 completes transmitting from the start or restart of unmodulated signal transmission until time T ₁ , assuming that communication is proceeding normally. _{N s} is a natural number. In the examples shown in FIGS. 6 to 8 , N _s is set to 6.

In addition, if the data collection control unit 24 acquires a data block that has already been acquired, it may discard the acquired data block without saving it.

If the data collection control unit 24 does not acquire a data block within the time T _ad [i] from the transition to state S12, it commands the transmitter 22 to stop transmission and waits for the time T _ss to pass (S11, S13). After the time T _ss has passed from the transition to state S13, it commands the transmitter 22 to resume transmission, sets i to 2, sets n _sm to 0, and returns to state S12. T _ss is the time at which the data collection control unit 24 lowers the transmission control signal to low level when it detects a missing data block.

Note that the transmission of the unmodulated signal will stop after the command, and the transmission of the unmodulated signal will start after the command.

The data collection control unit 24 ends data collection when it receives a notification of data transmission completion from the data transmission device 30 while in state S12, or when it has not finished data collection by time T _em after receiving a notification of arrival at the destination. T _em represents the time the data collection control unit 24 waits before canceling the data collection process.

5, when the communication control unit 36 detects a rising edge of the voltage V _nms after notifying the data collection device 20 that preparation for transmission is complete, it sets n and n _ss to 0 and transmits the (n+1)th data block (S21). n represents the number of data blocks that the communication control unit 36 considers to have transmitted up to the present. n _ss represents the number of data blocks transmitted by the communication control unit 36 from the start or restart of transmission of the unmodulated signal to the present without a stop of transmission of the unmodulated signal.

If the communication control unit 36 detects a falling edge of the voltage V _nms during transmission of the n+1th data block, it stops transmitting the n+1th data block, i.e., it stops outputting the modulated signal ms carrying the n+1th data block, and waits for detection of a rising edge of the voltage V _nms (S22). State S22 is an example of the "first standby state" of the present invention. If a rising edge of the voltage V _nms is detected, it sets n to the smaller of 0 and n-n _d -1, sets n _ss to 0, and transitions to state S21. If a rising edge of the voltage V _nms is not detected within the time T _es elapsed after transitioning to state S22, the data transmission process ends. n _d corresponds to the integer part of the quotient obtained by dividing T _d by T _db and is 0 or a natural number. Here, T _d is the time, assuming that the receiver 23 detects an error in the data block, from when the communication control unit 36 completes transmission of that data block to when the communication control unit 36 stops transmitting the data block due to the error in that data block. T _db is the time required to transmit one data block. In the examples shown in Figures 6 to 8, n _d is set to 0. In the example shown in Figure 9, n _d is set to 1. _{T es} represents the time that the communication control unit 36 waits before terminating the data transmission process.

When the communication control unit 36 completes transmission of the (n+1)th data block, it increments the values of n and n _ss by one.

Then, the communication control unit 36 returns to state S21 if n is not equal to N and n _ss is not equal to N _s , where N represents the total number of data blocks that the communication control unit 36 will transmit.

After incrementing the values of n and _{n_ss} by 1 as described above, if n is not equal to N and _{n_ss} is equal to _{N_s} , the communication control unit 36 waits for the passage of time _{T_sd} from the completion of transmission of the nth data block (S23). After the passage of time _{T_sd} , the communication control unit 36 waits for the detection of a high-level voltage _{V_nms} (S24). State S24 is an example of the "second standby state" of the present invention. If the communication control unit 36 detects a high-level voltage _{V_nms} , it sets _{n_ss} to 0 and transitions to state S21. If the communication control unit 36 does not detect a high-level voltage _{V_nms} within the time δ elapsed since transitioning to state S24, it transitions to state S22. _{T_sd} is set to satisfy _{T_sd} < _{T_s} < _{T_sd} + δ, where _{T_s} = _{T_1} + _{T_2} - _{T_db} × _{N_s} . δ is the time during which the communication control unit 36 waits for detection of the high-level voltage V _nms when in state S24.

After incrementing the values of n and _{n_ss} by 1 as described above, if n is equal to N, the communication control unit 36 notifies the data collection device 20 of the completion of data transmission (S25), and ends the data transmission process.

Here, the set value of time _Tss will be described. Time _Tss is set long enough so that the following conditions are satisfied. First, time _Trt exceeds time _Tsd + δ. Assuming that the data collection control unit 24 detects a missing data block, _Trt represents the time during which voltage _Vnms is at a low level due to the missing data block. Second, assuming that the data collection control unit 24 detects a missing data block, after issuing an instruction to resume transmission of the unmodulated signal, the data collection control unit 24 acquires only the data blocks that the communication control unit 36 began transmitting after issuing the instruction to resume transmission.

Furthermore, the constants used in the data collection system 10 will be described. The values of _T1 , _T2 , _Ns , _Tad [i], _Tss , _Tem , _Tsd , δ, _nd , and _Tes are predetermined and do not change during data collection. The value of N is determined during transmission preparation and does not change during data collection.

In the first example shown in FIG. 6 , when the data collection control unit 24 raises the transmission control signal to a high level, the transmitter 22 begins transmitting an unmodulated signal. When the communication control unit 36 detects the rising edge of the voltage V _nms , it transmits data blocks in order, starting with the first one. When the receiver 23 receives a data block, it performs error detection on that data block. When the data collection control unit 24 acquires a data block from the receiver 23, it stores that data block. Here, the data collection control unit 24 waits for the first data block for a time T _ad [2] from the rising edge of the transmission control signal. Furthermore, for the second to sixth data blocks, the data collection control unit 24 acquires and stores the data block, and then waits for the next data block for a time T _ad [0]. After transmitting the sixth data block, the communication control unit 36 stops transmitting the data block. The transmitter 22 transmits an unmodulated signal for a time T ₁ , and then stops transmitting the unmodulated signal for a time T ₂ . The communication control unit 36 waits a time _Tsd after completing the transmission of the sixth data block, and if it detects a high-level voltage _Vnms within the time δ, it starts transmitting the seventh data block. When the receiver 23 receives the seventh data block, it performs error detection on that data block. When the data collection control unit 24 acquires the seventh data block from the receiver 23, it stores that data block. Here, the data collection control unit 24 waits a time _Tad [1] for the seventh data block after acquiring and storing the sixth data block. The data collection process is performed in the same manner thereafter.

In the second example shown in Figure 7, the receiver 23 detects an error in the tenth block of data. The data recovery control unit 24 does not acquire block data within time T _ad [0] after acquiring and saving the ninth data block, so it lowers the transmission control signal to low level for time T _ss . The transmitter 22 temporarily stops transmitting the unmodulated signal in response to the falling edge and subsequent rising edge of the transmission control signal. The communication control unit 36 detects the falling edge of voltage V _nms during transmission of the eleventh block of data and stops transmission of the eleventh data block. Thereafter, when the communication control unit 36 detects the rising edge of voltage V _nms , it transmits data blocks in order, starting with the tenth.

In the third example shown in FIG. 8 , an unmodulated signal is transmitted from time t _b1 to time t _b2 , but the voltage V _nms is low. The communication control unit 36 detects the falling edge of the voltage V _nms at time t _b1 and stops transmitting the ninth data block. Then, it detects the rising edge of the voltage V _nms at time t _b2 and starts transmitting the eighth data block. Because the receiver 23 does not receive the entire ninth data block, it does not perform error detection on the ninth data block. Because the data recovery control unit 24 does not acquire the ninth data block within time T _ad [0] after acquiring and saving the eighth data block, it lowers the transmission control signal to low for time T _ss . The transmitter 22 temporarily stops transmitting the unmodulated signal in response to the falling edge and subsequent rising edge of the transmission control signal. The communication control unit 36 detects the falling edge of the voltage V _nms during transmission of the eighth data block and stops transmitting the eighth data block. Then, it detects the rising edge of the voltage V _nms and transmits data blocks sequentially, starting with the seventh data block.

When data collection is complete, the data collection control unit 24 of the data collection device 20 stops transmission from the transmitter 22 and notifies the drone 11 of the completion of data collection. The data collection control unit 24 then writes the data blocks stored in its own memory to the storage unit 25. Upon receiving the notification of the completion of data collection, the drone 11 returns to the base station. When the communication control unit 36 of the data transmission device 30 detects a low-level voltage V _nms continuously for more than a predetermined time, it transitions to sleep mode.

10 is a state transition diagram showing the data transmission process of the communication control unit 36 according to a modification of the first embodiment. The data transmission process according to the modification of the first embodiment differs from the data transmission process according to the first embodiment in the following respects. Specifically, after completing the transmission of the (n+1)th data block and incrementing the values of n and n _ss by 1, if n is not equal to N, the communication control unit 36 returns to S21. Furthermore, if a falling edge of the voltage V _nms is detected during the transmission of the (n+1)th data block and n _ss is equal to N _s , the communication control unit 36 waits for the passage of time T _sd from the completion of the transmission of the nth data block (S23). If a falling edge of the voltage V _nms is detected during the transmission of the (n+1)th data block and n _ss is not equal to N _s , the communication control unit 36 transitions to state S22.

11 is an example of a timing chart showing the data collection process of the data collection system 10 according to a modified example of the first embodiment. The communication control unit 36 detects a falling edge of the voltage V _nms during transmission of the seventh data block and stops transmission of the seventh data block. Thereafter, the communication control unit 36 detects a rising edge of the voltage V _nms and starts transmission of the seventh data block.

According to the first embodiment, if the data recovery device 20 detects an error in a received data block or if a data block that was scheduled to be received is not received within a predetermined time, it temporarily stops transmitting the unmodulated signal. The data transmission device 30 then transmits or retransmits the data block after resuming transmission of the unmodulated signal. By correcting communication errors in this way, reliable communication can be achieved.

Furthermore, the data collection device 20 and data transmission device 30 do not need to perform two-way communication. The transmitter 22 does not need to transmit a modulated signal, and the data transmission device 30 does not need a receiver. This simplifies the collection process and system configuration.

Second Embodiment
The data collection system according to the second embodiment of the present invention differs from the data collection system according to the first embodiment of the present invention in terms of data transmission processing. The configuration of the data collection system according to the second embodiment is substantially the same as the configuration of the data collection system according to the first embodiment of the present invention shown in Figures 1 to 3. Therefore, the components of the data collection system according to the second embodiment that are substantially the same as the components of the data collection system according to the first embodiment are denoted by the same reference numerals as those components of the data collection system according to the first embodiment, and a description of the configuration of the data collection system according to the second embodiment will be omitted.

12 is a state transition diagram showing the data transmission process of the communication control unit 36 according to the second embodiment. The data transmission process according to the second embodiment differs from the data transmission process according to the first embodiment in the following respect. After completing transmission of the (n+1)th data block and incrementing the values of n and n _ss by 1, if n is not equal to N and n _ss is equal to _Ns , the communication control unit 36 waits for detection of a rising edge of the voltage V _nms (S22).

13 is an example of a timing chart showing the data collection process of the data collection system 10 according to the second embodiment. After completing the transmission of the sixth data block, the communication control unit 36 waits for the rising edge of the voltage V _nms . When the rising edge of the voltage V _nms is detected, the communication control unit 36 transmits data blocks in order, starting from the sixth data block.

14 is a state transition diagram showing the data transmission process of the communication control unit 36 according to a modification of the second embodiment. The data transmission process according to the modification of the second embodiment differs from the data transmission process according to the second embodiment in the following respects. That is, when the communication control unit 36 completes transmission of the (n+1)th data block, it increments the value of n by 1 and returns to state S21. Furthermore, the communication control unit 36 does not need to define n _ss and N _s .

15 is an example timing chart showing the data collection process of the data collection system 10 according to a modified example of the second embodiment. The communication control unit 36 detects a falling edge of the voltage V _nms during transmission of the seventh data block and stops transmission of the seventh data block. Thereafter, the communication control unit 36 detects a rising edge of the voltage V _nms and starts transmission of the sixth data block.

According to the second embodiment, the collection process can be further simplified.

In another embodiment, the data collection device 20 may be mounted on another mobile body instead of the drone 11.

Alternatively, instead of being mounted on a mobile object, the data collection device 20 may be installed, for example, inside a building. The data collection device 20 may then transmit the observation data to a base station, for example, using a wide area network.

In addition, the data transmission device 30 may communicate with another data storage device instead of the observation device 12 and transmit other data instead of the observation data.

Finally, the above description of the embodiments is illustrative in all respects and not restrictive. Those skilled in the art may readily appreciate variations and modifications. The scope of the present invention is defined not by the above embodiments but by the claims. Furthermore, the scope of the present invention includes modifications from the embodiments within the scope of the claims and their equivalents.

F...power supply terminal R...reset terminal S...set terminal 10...data collection system 11...drone 12...observation device 20...data collection device 22...transmitter 23...receiver 24...data collection control unit 25...memory unit 30...data transmission device 31...antenna 32...communication unit 33...rectification modulation circuit 34...voltage detection circuit 35...voltage holding circuit 36...communication control units 211, 212...antenna

Claims (6)

An antenna and a communication unit are provided,
the communication unit modulates a reflected wave of the unmodulated signal received by the antenna and transmits a plurality of ordered data blocks in sequence;
A data transmitting device in which the communication unit has completed transmission of data blocks up to the nth data block, and when an unmodulated signal is received in a first standby state in which it waits for the resumption of reception of the unmodulated signal, it transmits data blocks in order from the n- _ndth data block, where n _d is a predetermined value and is also 0 or a natural number. When the communication unit no longer receives an unmodulated signal before completing transmission of _Ns data blocks without interruption, the communication unit transitions to the first standby state, where _Ns is a predetermined value and is a natural number;
the communication unit stops transmitting the data blocks after completing the transmission of the _Ns data blocks without stopping midway;
the communication unit transitions to a second standby state in which it waits for reception of an unmodulated signal after a predetermined time T _sd has elapsed since completion of transmission of the N _s data blocks;
the communication unit has completed transmission of the n-th data block and, when receiving an unmodulated signal in the second standby state, transmits data blocks in order from the n+1-th data block;
2. The data transmitting device according to claim 1, wherein the communication unit transitions to the first standby state if it does not receive an unmodulated signal until a predetermined time δ has elapsed since the transition to the second standby state. The data transmission device of claim 1, wherein the communication unit transitions to the first standby state when an unmodulated signal is no longer received during transmission of a data block. an antenna, a transmitter, a receiver, and a data collection control unit;
the transmitter transmits an unmodulated signal from the antenna based on a command from the data collection control unit;
The receiver receives the data block carried on the reflected wave of the unmodulated signal by the antenna, and if no error is detected in the received data block, outputs the received data block, and if an error is detected in the received data block, does not output the received data block;
The data recovery control unit stores the acquired data block if it acquires the data block from the receiver within a predetermined period, and instructs the transmitter to temporarily stop transmitting the unmodulated signal if it does not acquire the data block from the receiver within the predetermined period. A data collection system comprising the data transmission device of any one of claims 1 to 3 and the data collection device of claim 4. Further comprising a moving body and an observation device;
the data collection device is mounted on the moving body,
The data collection system according to claim 5 , wherein the data transmission device acquires observation data from the observation device and transmits a data block including the observation data.