JP5586129B2 - Positioning system and relay device - Google Patents

Description

  The present invention relates to a positioning system that estimates a target position using a plurality of relay devices.

  For example, many methods for measuring a target position using radio wave radiation have been known. As an example, a method is known in which weak radio waves radiated from a target are received by a plurality of detection devices, and a target position is estimated by referring to the plurality of detection signals. However, when such a method is adopted, the amount of detection signal information is large in spite of the limitation of communication resources, so that the detection signal that can be sent is limited. On the other hand, in the following Patent Documents 1 to 4, methods for reducing the amount of information by deleting redundant portions from the detection signal information and transmitting in a limited band are proposed.

  Specifically, in Patent Documents 1 to 3 below, positioning of a target position is performed using data of a single sensor. In this case, since it is easy to guess a portion that can be deleted in the sensor data, it is easy to extract a characteristic portion. Also, in Patent Document 4 below, a certain sensor sends transmission information to another sensor separately from the detection signal, and each of the plurality of sensors performs positioning using the transmitted information. In this case, the transmission information is shared among a plurality of devices, thereby realizing a reduction in bandwidth.

  Another means for improving transmission efficiency is network coding technology. In conventional packet communication, each node performs an exchange process that distributes input information to a desired destination, but does not process user information in the packet. On the other hand, in the network coding technique, each node performs coding (encoding) in addition to exchange, thereby enabling efficient transmission as a whole network (see Non-Patent Documents 1 to 3 below).

JP 2003-240845 A JP 2005-121426 A JP-A-3-295485 JP-A-5-297125 R. Ahlswede et. al., “Network information flow” IEEE trans. on Information Theory, vol.46, no.4, July, 2000, pp. 1204-1216 Miki Yamamoto “Network Coding” Journal of IEICE Vol. 90, no. 2, February 2007, pp. 111-116 S.Y. R. Li et. Al., “Linear network coding,” IEEE trans. on Information Theory, vol.49, no. 2, Feb. 2003, pp. 371-381

  However, in the case of using a plurality of sensors, unlike the cases of Patent Documents 1 to 3, it is difficult to estimate a characteristic part by individual sensor data determination. Therefore, in the case of a plurality of sensors, a feature data extraction method different from the case of a single sensor is required, but this is not described.

  Moreover, in the said patent document 4, the process which relays efficiently the information which several sensors detected is not described in particular.

  Moreover, in the said nonpatent literature 1-3, although it describes conceptually about making transmission efficient by performing a linear operation to data in each node, the concrete assumption which actual original data in a communication network was assumed. There is no mention of any significant processing.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a positioning system capable of improving transmission efficiency when a plurality of nodes transmit detection data via a network.

  In order to solve the above-described problems and achieve the object, the present invention provides a relay device configured to relay a signal radiated from a target to be measured as detection information, and the relay device configured by the relay devices. A positioning system that collects a plurality of pieces of detection information obtained from a network and performs positioning of the target, wherein the relay device receives two pieces of detection information when receiving a plurality of pieces of detection information. Information pattern comparing means for comparing two detection information relative to each other as a unit and retaining the information pattern when an information pattern indicating a characteristic match or mismatch is extracted; When an information pattern is held, new detection information including the information pattern as a first encoding result is generated, while the information pattern If not, a predetermined encoding process is performed using the two detection information for which the information pattern could not be extracted, and new detection information including the encoding result as the second encoding result is obtained. Encoding means for generating, and detection information transmitting means for transmitting any one of the detection information generated by the encoding means for all combinations of the two detection information as a unit. And

  According to the present invention, when a plurality of pieces of detection information are received by a plurality of relay apparatuses, encoding by network coding is performed, so that the amount of information can be reduced as much as possible and efficient data transmission is realized. There is an effect that it is possible.

  Hereinafter, embodiments of a positioning system according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment.
FIG. 1 is a diagram illustrating a configuration example of a positioning system according to the present embodiment. The positioning system shown in FIG. 1 has a target 1 as a positioning target, and includes a detection relay device 2-m (m = 1, 2,...) And a positioning device 3, and each detection relay device and the positioning device 3 are connected to a communication network 4. Connected through. Each detection relay device and positioning device 3 includes an antenna 5.

  In the positioning system of FIG. 1, a plurality of detection relay devices receive a radiated wave radiated from the target 1. Information of detection signals (hereinafter referred to as detection information) received by a plurality of detection relay devices is relayed by the detection relay device and collected by the positioning device 3 via the communication network 4. The positioning device 3 estimates the position of the target 1 based on the collected detection signals. In the communication network 4, the detection information is transmitted through an appropriate route according to the network status. The antenna 5 receives the reflected wave from the target 1. In addition, detection information is exchanged between the detection relay devices or between each detection relay device and the positioning device 3.

  Further, it is assumed that each of the detection relay devices and the positioning device 3 is mounted on an aircraft or a ship and moves. These may be fixed on the ground. In this embodiment, an example is shown in which a detection relay device having the functions of a detection device and a relay device and a positioning device are installed. However, the detection device, the relay device, and the positioning device are each installed as one device. May be. Moreover, you may install the apparatus which has a function of a detection apparatus, a relay apparatus, and a positioning apparatus.

  2 and 3 are diagrams schematically showing a usage pattern of the positioning system of the present embodiment. 2 and 3, only the detection relay apparatuses 2-1 and 2-2 are displayed as the detection relay apparatuses. FIG. 2 shows a case where positioning is performed using a radiated wave radiated by the target 1 for its own purpose. FIG. 3 shows a case where a reflected wave from the target 1 with respect to a general radio wave such as a broadcast wave is used. This is the case.

  FIG. 4 is a block diagram illustrating a configuration example of the detection relay device 2-m. The detection relay device includes a detection signal reception unit 21, an information storage unit 22, a delay addition unit 23, an information pattern comparison unit 24, an information pattern storage unit 25, an encoding unit 26, and a detection information transmission unit 27. . When receiving the detection signal from the antenna 5, the detection signal receiving unit 21 stores the detection signal in the information storage unit 22. The delay adding unit 23 reads the detection signal from the information storage unit 22 and delays by adding several kinds of values determined by the combination of the shift register and the counter. When the information pattern comparison unit 24 compares the detection signals after the delay is added and detects the feature of the signal pattern, the information pattern comparison unit 24 stores the detected signal characteristics in the information pattern storage unit 25. The encoding unit 26 encodes the detection signal by linear calculation, creates detection information, and outputs the detection information to the detection information transmission unit 27. The detection information transmission unit 27 transmits detection information.

  FIG. 5 is a block diagram illustrating a configuration example of the positioning device 3. The positioning device includes a detection information receiving unit 31, an information storage unit 32, a decoding unit 33, and a positioning unit 34. Also, an antenna 5 is provided. When the detection information reception unit 31 receives a plurality of detection information (for example, detection information # 1 to #n) via the antenna 5, the detection information reception unit 31 stores the detection information in the information storage unit 32. The decoding unit 33 acquires and decodes the detection information from the information storage unit 32 according to a command from the detection information reception unit 31, and the original detection signal, that is, the radiated wave from the target 1 is first received by the detection relay device. Get the signal when done. The positioning unit 34 estimates the position of the target 1 using the decoded detection signal and outputs a positioning result.

  FIG. 6 is a conceptual diagram showing an example of a network configuration assumed by the positioning system of the present embodiment. Here, the detection relay device has a multi-stage configuration, and detection information relayed by a plurality of detection relay devices is collected by the positioning device.

  In FIG. 6, numbers from # 1 to # 11 are assigned to the detection relay devices. Further, positioning devices 3A and 3B are provided as positioning devices. The radiated waves s1, s2, and s3 radiated from the target 1 are transmitted toward the first detection relay devices # 1, # 2, and # 3, respectively. The radiated waves s1, s2, and s3 are relayed as detection signals X1, X2, and X3 by the first-stage detection relay device and transmitted toward the second-stage detection relay devices # 4, # 5, # 6, and # 7. Is done. The detection signals X1, X2, and X3 are processed by the second-stage detection relay device, relayed as detection information, and transmitted to the third-stage detection relay devices # 8, # 9, # 10, and # 11. The Further, the detection information is relayed by the third-stage detection relay device and transmitted toward the positioning device 3A or 3B.

  Here, the operation of the positioning system configured as described above will be described focusing on the flow of detection signals. FIG. 7 is a flowchart showing signal transmission processing in the positioning system. In FIG. 6, the radiated wave radiated from the target 1 is relayed by the first-stage detection relay device, the second-stage detection relay device, and the third-stage detection relay device, and reaches the positioning device. In FIG. 7, steps S2 to S4 are processing by the first-stage detection relay device, step S5 is processing by the second and subsequent detection relay devices, and steps S6 to S9 are processing by the positioning device. In the present embodiment, an example in which the detection relay device has three stages is shown, but the same is true even if there are more stages.

  In FIG. 7, when the target 1 emits a radiated wave (step S1), the detection signal receiving unit 21 of the first-stage detection relay device receives this as a detection signal (step S2). And the received detection signal is memorize | stored in each information storage part 22 as detection information (step S3). In the example of FIG. 6, the detection relay apparatus in the first stage receives only one detection signal, so that the detection signal reception unit 21 sends the delay addition unit 23, the information pattern comparison unit 24, and the encoding unit 26 to that effect. To be notified. Upon receiving this notification, the delay adding unit 23 and the information pattern comparing unit 24 stop the processing. In addition, the encoding unit 26 that has received this notification reads out the detection information from the information storage unit 22 and outputs the detection information to the detection information transmission unit 27 without performing encoding. The detection information transmission unit 27 transmits the detection information to the next stage (second stage) detection relay device via the communication network 4 (step S4). Next, processing by the second and subsequent detection relay devices is performed (step S5).

  FIG. 8 is a flowchart for explaining the details of the processing in the detection relay apparatus in the second and subsequent stages (here, the second and third stages). Here, the detection relay device # 5 of FIG. 6 will be described as an example. The detection relay device # 5 receives the radiation wave radiated from the target 1 as detection information X1 and X2 via the detection relay devices # 1 and # 2.

  In FIG. 8, when receiving the detection information X1 and X2 from the upstream detection relay device, the detection signal reception unit 21 of the detection relay device # 5 stores the detection information in the information storage unit 22 (step S11). Next, the delay adding unit 23 reads the detection information X1 and X2 from the information storage unit 22, and adds a delay to the detection information X1 and X2 (step S12). Since this delay is added to relatively shift the detection information X1 and X2, it is not necessary to add it to both of the detection information X1 and X2. For example, it may be added to only one of them. Good. In the present embodiment, one data, for example, the timing of the detection signal X1 is sequentially shifted using a counter, and the detection information X1 after adding a delay and the detection information X2 without adding a delay are information patterns. Output to the comparison unit 24. Then, the information pattern comparison unit 24 sequentially compares the received detection information (step S12), and when the characteristic of the detection information pattern (corresponding to characteristic coincidence or non-coincidence described later) can be extracted (step S13: Yes), this is stored in the information pattern storage unit 25 as an information pattern (step S14), and that is notified to the encoding unit 26. In addition, the process which produces | generates the information pattern by said step S12, S13 is corresponded to the encoding by network coding. On the other hand, when the feature of the detection information pattern cannot be extracted (step S13: No), the information pattern comparison unit 24 notifies the encoding unit 26 to that effect.

  Here, the details of the comparison process of the detection information executed by the information pattern comparison unit 24 will be described. FIG. 9A is a diagram illustrating a waveform example of the detection information X1, and FIG. 9B is a diagram illustrating a waveform example of the detection information X2. In these figures, the horizontal axis represents time, and the vertical axis represents the amplitude of detection information. Also, the time “T0” is set as the reference time. The detection information X1 and the detection information X2 are obtained by sampling the radiation wave radiated from the same target 1 by the detection relay device and sampling at intervals dt, and the amplitudes of many parts are equal. FIGS. 9-3 and 9-4 are diagrams for comparing the patterns of the detection information X1 and the detection information X2. FIG. 9C is a diagram illustrating a state in which the detection information X1 of FIG. 9-1 and the detection information X2 of FIG. As illustrated in FIG. 9C, the detection information X1 and the detection information X2 indicate different values over a period from time T1 to time (T1 + T2). 9-4 is a diagram illustrating a state in which the signal obtained by delaying the detection information X1 of FIG. 9-1 by one sampling time unit (dt) and the detection information X2 of FIG. 9-2 are overlapped. In FIG. 9-4, the detection information X1 (dt delay) and the detection information X2 indicate values that are substantially the same over a period from time (T1 + dt) to time (T1 + dt + T2). A characteristic match or mismatch between the detection information X1 and X2 can be extracted by, for example, taking an exclusive OR of the detection information added with delay and verifying the result.

  The obtained comparison result is recorded in the information pattern table in the information pattern storage unit 25 by the information pattern comparison unit 24 of the detection relay device. FIG. 10 is a diagram illustrating an example of data in the information pattern table. The information pattern table includes, for example, an identifier of detection information 1 (X1), an identifier of detection information 2 (X2), a delay added to each detection information, a start time when a characteristic pattern was seen, a characteristic Data such as the time at which a continuous pattern was observed, the type of pattern, and the like are stored. For example, “mismatch / match” is registered as the pattern type. In the example of FIG. 9-3, the detection information X1 (zero delay) and the detection information X2 (zero delay) indicate a mismatch (characteristic mismatch) exceeding a predetermined range over a period from time T1 to time (T1 + T2). (See FIG. 9-3), the information pattern is registered as in the first entry in FIG. Further, in the example of FIG. 9-4, a match (characteristic match) in which the detection information X1 (delay 1) and the detection information X2 (zero delay) are within a predetermined range over a period from time T1 + 1 to time (T1 + 1 + T2). Therefore, the information pattern is registered as in the second entry in FIG.

  As described above, after the processing of steps S13 and S14 is completed, the encoding unit 26 that receives the notification from the information pattern comparison unit 24 registers whether or not the detection information to be relayed is registered in the information pattern table of the information pattern storage unit 25. Is determined (step S15). If an information pattern exists (step S15: Yes), the information pattern (for example, registered data in FIG. 10) is set as detection information transmitted by the own apparatus as a result of encoding by network coding (step S16). ). On the other hand, when there is no information pattern (step S15: No), the original detection information (detection information X1 and X2) stored in step S11 is read from the information storage unit 22 and is used to code the network coding. And the encoding result is set in the detection information transferred by the own apparatus (step S17). The above encoding is based on a general method shown in the above-mentioned Non-Patent Documents 1 to 3. Next, the encoding unit 26 outputs the obtained detection information to the detection information transmission unit 27, and the detection information transmission unit 27 passes the received detection information to the detection relay device in the next stage via the communication network 4. Transmit (step S18). In addition, when transmitting an information pattern as detection information, information transmission with small resources is possible. The detection information in which the information pattern is set in step S16 and the detection information in which the encoding result is set in step S17 include a flag for identifying them. Further, the detection information further includes information indicating which detection relay device has been obtained.

  The third and subsequent detection relay devices will be described by taking, for example, the detection relay device # 9 in FIG. 6 as an example (flow chart in FIG. 7: step S5). Here, processing different from the detection relay device # 5 will be described. Further, it is assumed that the detection relay device # 9 receives three detection information from the detection relay devices # 4, # 5, and # 6. For example, the detection relay device # 9 performs the processing of FIG. 8 for all combinations of two when the detection information in which the encoding results in three or more steps S17 are set is obtained. Further, the detection relay device # 9 determines that the combination of the detection information obtained from the detection relay devices # 4, # 5, and # 6 is the detection information in which the encoding result in step S17 is set. 8 is performed. On the other hand, when one of the pieces of detection information obtained from the detection relay devices # 4, # 5, and # 6 is detection information in which the encoding result obtained in step S17 is set, the detection relay device # 9 Processing such as extraction and encoding is not performed, and processing similar to that of the first-stage detection relay device is performed for the detection information. When the information pattern is obtained from the detection information, the information amount of the information pattern is sufficiently reduced, so no further processing is performed, and the detection information is processed in the same manner as the first-stage detection relay device. .

  In the example of FIG. 6, only the detection relay device at the first stage receives the radiated wave as a detection signal, but actually the detection relay devices at the second and subsequent stages may directly receive the detection signal. In this case, the directly received detection signal and the detection information obtained from the preceding detection relay device (detection information in which the encoding result in step S17 is set) are handled in the same row (step S11 in FIG. 8). When a plurality of these are received, the process of FIG. 8 is performed as described above.

  As described above, after the processing of the second and subsequent detection relay devices is completed (flowchart in FIG. 7: step S5), the detection information receiving unit 31 of the positioning device (here, the positioning device 3A) receives the previous detection information. When detection information (detection information # 1 to #n) is received from the apparatus (step S6), the information is stored in the information storage unit 32. Then, the decoding unit 33 decodes the original detection signal based on the collected detection information (step S7). The decoding here is based on, for example, a general method disclosed in Non-Patent Documents 1 to 3 described above. Finally, the positioning unit 34 estimates the target position based on the decoded detection information X1 and X2 (step S8), and outputs the obtained positioning result (step S9).

  In the detection relay device, when encoding by network coding is performed, the information of the detection information 1 and X2 may coincide with high accuracy (more than a predetermined probability) depending on the timing. In this case, most of the bits obtained by exclusive OR of the two pieces of information become zero. Therefore, in this embodiment, instead of sending the bit string data that is almost zero, the compressed data is transmitted by designating the bit position of one. Thereby, the transmission amount of data can be significantly reduced. Even if the data reduced in this way is transmitted, the decoding of the data in the positioning device can be realized in the same way as the normal network coding.

  As described above, in the positioning system of the present embodiment, the target radiated wave is received as a detection signal by a plurality of detection relay devices, and is encoded by network coding (detection information in steps S12 and S13 is time-sequentially). Equivalent to encoding for extracting an information pattern by performing a linear operation while shifting to, and encoding when the information pattern is not obtained in step S17). Then, the obtained encoded signal is transmitted as detection information. Further, the positioning device decodes the collected detection information and obtains a positioning result based on the decoding result. Thereby, when the information pattern can be extracted, the information pattern is transmitted, so that transmission of the detection signal itself having a large amount of information can be avoided.

  As described above, in the present embodiment, when a plurality of pieces of detection information are received by a plurality of detection relay apparatuses, the amount of information is reduced as much as possible by performing coding by network coding, and efficient data transmission is performed. It was decided to do. As a result, transmission efficiency can be improved, so that positioning using information obtained from a plurality of detection relay devices is possible even when it is difficult to send and receive large amounts of data due to the limitation of the bandwidth used in the communication network. Become. Furthermore, even when the detection signal is weak, such as when the target uses a radiation wave that is radiated by itself, it is possible to perform highly accurate positioning of the target by collecting a plurality of detection signals. In this case, since it is not necessary to emit the reference radio wave toward the target in order to obtain the reflected wave, it is possible to reduce the risk of the presence of the detection device being known from the target side.

  As described above, the positioning system according to the present invention is useful when the bandwidth of the communication network is limited, and is particularly suitable for performing high-precision positioning by collecting a large amount of data.

It is a figure which shows the structural example of a positioning system. It is a figure which shows the usage pattern of a positioning system typically. It is a figure which shows the usage pattern of a positioning system typically. It is a block diagram which shows the structural example of a detection relay apparatus. It is a block diagram which shows the structural example of a positioning apparatus. It is a conceptual diagram which shows an example of the network structure which a positioning system assumes. It is a flowchart which shows the transmission process of the signal in a positioning system. It is a flowchart for demonstrating the detail of the process in the detection relay apparatus after the 2nd step | paragraph. It is a figure which shows the example of a waveform of detection information 1st. It is a figure which shows the example of a waveform of the detection information 2nd. It is a figure for comparing the pattern of detection information part 1 and detection information part 2. It is a figure for comparing the pattern of detection information part 1 and detection information part 2. It is a figure which shows the example of data of an information pattern table.

Explanation of symbols

1 target 2-m detection relay device 3, 3A, 3B positioning device 4 communication network 5 antenna 21 detection signal reception unit 22 information storage unit 23 delay addition unit 24 information pattern comparison unit 25 information pattern storage unit 26 encoding unit 27 detection information Transmission unit 31 Detection information reception unit 32 Information storage unit 33 Decoding unit 34 Positioning unit

Claims (4)

When a detection signal that is a signal radiated from a target that is a positioning target is directly received, the received detection signal is relayed as first detection information, and when a single first detection information is received The received first detection information is relayed as it is, and when a plurality of the first detection information is received, the plurality of received first detection information is encoded, and the encoded result is relayed as the second detection information. A plurality of relay devices that relay the received second detection information as it is when the second detection information is received ;
A positioning device to collect the first detection information and the second detection information obtained from the configured relay network performs positioning of the target by the previous SL plurality of relay devices,
A positioning system comprising:
The relay device is
As a configuration for generating the second detection information,
A plurality of the first detection information is received, and for all combinations in which the two first detection information are used as a unit, the two first detection information are compared while relatively shifting the two first detection information. If there is a period in which the amplitudes of these are almost the same in many parts but not in a part, an information pattern indicating a characteristic mismatch regarding the non-matching period and the shift amount (delay amount) is displayed. If there is a period in which the amplitudes of the two pieces of first detection information do not match in many parts but match in some parts, the matching period and the shift amount (delay amount) And an information pattern comparing means for extracting an information pattern indicating a characteristic coincidence and holding the extracted information pattern as second detection information;
For each combination of the two first detection information could not extract the information pattern in the information pattern comparing means, have rows encoding process by network coding, and the coding results second detection information Encoding means for
And detection information transmission means for transmitting the second detection information generated in the second detection information and the encoding means being held in the previous SL information pattern comparing means,
A positioning system comprising: When the relay device that has received the signal radiated from the target has not received the first detection information from another relay device, the relay device transfers the received signal as the first detection information. When the first detection information is received from the relay device, the information pattern comparison unit performs comparison processing on the first detection information and the received signal and tries to extract the information pattern. The positioning system according to claim 1 . The relay device, a positioning system according to claim 1 or 2 reflected wave, characterized in that it can receive a signal emitted from the target with respect to a predetermined reference signal. When a detection signal that is a signal radiated from a target that is a positioning target is directly received, the received detection signal is relayed as first detection information, and when a single first detection information is received The received first detection information is relayed as it is, and when a plurality of the first detection information is received, the plurality of received first detection information is encoded, and the encoded result is relayed as the second detection information. A relay device that relays the received second detection information as it is when the second detection information is received ;
As a configuration for generating the second detection information,
A plurality of the first detection information is received, and for all combinations in which the two first detection information are used as a unit, the two first detection information are compared while relatively shifting the two first detection information. If there is a period in which the amplitudes of these are almost the same in many parts but not in a part, an information pattern indicating a characteristic mismatch regarding the non-matching period and the shift amount (delay amount) is displayed. If there is a period in which the amplitudes of the two pieces of first detection information do not match in many parts but match in some parts, the matching period and the shift amount (delay amount) And an information pattern comparing means for extracting an information pattern indicating a characteristic coincidence and holding the extracted information pattern as the second detection information;
For each combination of the two first detection information could not extract the information pattern in the information pattern comparing means, have rows encoding process by network coding, and the coding results second detection information Encoding means for
And detection information transmission means for transmitting the second detection information generated in the second detection information and the encoding means being held in the previous SL information pattern comparing means,
A relay device comprising:

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