WO2023219014A1

WO2023219014A1 - Encoding device and decoding device

Info

Publication number: WO2023219014A1
Application number: PCT/JP2023/016866
Authority: WO
Inventors: 一朗大西; 智恵子兼松; 寛之瀧澤; 吉田　真弓; 大輝岡本
Original assignee: ＡｐＴｅｃｈ株式会社
Priority date: 2022-05-09
Filing date: 2023-04-28
Publication date: 2023-11-16

Abstract

An encoding device according to the present invention comprises: a data acquisition means that acquires a plurality of pieces of data to be encoded; a space identification means that regards each piece of data constituting the plurality of pieces of data acquired by the data acquisition means as one-dimensional data, respectively, thereby defines the number of pieces of data constituting the plurality of pieces of data as a number of dimensions, and identifies, from among unit spaces obtained by virtually dividing a multi-dimensional space corresponding to the number of dimensions, a unit space corresponding to the plurality of pieces of data; and an encoding means that outputs, as encoded data of the plurality of pieces of data, identification information assigned to the unit space identified by the space identification means.

Description

Encoding device and decoding device

The present invention relates to an encoding device and a decoding device.

In order to reduce storage costs, communication costs, etc., it is desirable to suppress the amount of data. When the amount of data is relatively small, it is usually necessary to reversibly reduce the amount of data. This is because a change in the value of one bit has a large effect, and in many cases, the change in value makes the data meaningless.

A conventional method for reversibly reducing the amount of data is to use continuous data, such as position data representing the position of a moving object, to calculate the change from the previous position as a difference, and to generate difference data representing the difference. There is a differential method that allows transmission. In this difference method, after transmitting position data, difference data is transmitted instead of the position data, thereby reducing the amount of data to be transmitted and received. However, in the difference method, if the receiving side cannot receive the position data or the difference data, the receiving side cannot restore the position data. In response to such problems, it is also possible to reduce the amount of data by discarding predetermined high-order digits by planning the geographical locations of the receiving and transmitting sides in advance (see, for example, Patent Document 1). ).

JP2018-166248A

The position data whose upper digits are discarded is a data group including longitude data and latitude data. Such position data can be obtained by satellite positioning (satellite positioning system). In the method of reducing the amount of data by discarding the upper digits, the receiving side uses satellite positioning to generate data for the upper digits that are discarded for each of the longitude data and position data, and then restores the original position data. It is designed to restore accurately. However, in order to do this, the geographical locations of the receiving and transmitting sides must be planned in advance, and when transmitting and receiving location data, both the receiving and transmitting sides, that is, the encoding and decoding sides, must plan in advance. Must be moved to a geographical location. If this is not done, the receiving side cannot generate the upper digit data necessary for restoring the position data.

For this reason, the method of reducing the amount of data by discarding the upper digits requires different data to restore position data than the difference method. The existence of such data has another drawback in that it has low versatility and has very large restrictions on its use. If such problems are taken into consideration, it seems important to achieve reversible encoding (compression) of data while avoiding the need to acquire necessary data at any time. It is also important to be able to handle data groups that include multiple pieces of data, such as location data.

An object of the present invention is to provide an encoding device capable of reversibly encoding a data group without acquiring necessary data at any time, and a decoding device capable of restoring the data group. .

An encoding device according to an aspect of the present disclosure includes a data acquisition unit that acquires a plurality of data to be encoded, and a data acquisition unit that converts each data constituting the plurality of data acquired by the data acquisition unit into one-dimensional data. By considering that the number of data constituting the plurality of data is the number of dimensions, the unit corresponding to the plurality of data is selected from among the unit spaces that virtually divide the multidimensional space according to the number of dimensions. The apparatus includes a space specifying means for specifying a space, and an encoding means for outputting identification information assigned to the unit space specified by the space specifying means as encoded data of the plurality of data.

According to the present invention, data groups can be reversibly encoded without acquiring necessary data as needed. Furthermore, a data group can be restored from the data obtained by the encoding.

FIG. 2 is a diagram illustrating an application example of an encoding device and a decoding device according to an embodiment of the present invention. 1 is a diagram showing an example of a circuit configuration of a mobile body equipped with an encoding device according to an embodiment of the present invention. FIG. 1 is a functional block diagram showing an example of a functional configuration realized on a mobile body equipped with an encoding device according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an example of an encoding method adopted by an encoding device according to an embodiment of the present invention. FIG. 3 is a diagram illustrating an example of quantization of the entire space. 3 is a flowchart illustrating an example of each flow of encoding processing and decoding processing.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. Note that the embodiments described below are merely examples, and the technical scope of the present invention is not limited thereto. The technical scope of the present invention also includes various modifications.

FIG. 1 is a diagram illustrating an application example of an encoding device and a decoding device according to an embodiment of the present invention.
This application example is an example in which an encoding device is mounted on the moving body 1 in order to confirm the position of the moving body 1 and the like. Thereby, the mobile body 1 encodes the position data and transmits the position data as encoded data.

The movable body 1 may be an object that itself can be moved, but it may also be an object that is intended to be carried by a person or installed on an object that can be moved. Thereby, the mobile object 1 may be, for example, a smartphone, a smart watch, a drone, an airplane, or a car. It may also be implemented as a communication device mounted on or combined with the mobile body 1.

Position data is a group of data obtained by satellite positioning. The position data includes, for example, longitude data, latitude data, and altitude data. The mobile body 1 encodes the position data PD including these three pieces of data, and transmits the encoded position data PD. Furthermore, the mobile body 1 encodes and transmits state data SD representing the state of the mobile body 1 itself, the state of the person carrying the mobile body 1, or the environment in which the mobile body 1 is placed. It has become. The state data SD to be encoded is a data group containing two or more pieces of data.

The state data SD of the person carrying the device includes data (biological information) such as heart rate, heart rate variability, blood oxygen concentration, body temperature, activity level evaluation value, and sleep evaluation value. The status data SD may be part of a data group defined by standards such as ISO (International Organization for Standardization) 13606, HL (Health Level) 7, or open EHR (Electronic Health Records). That is, the status data SD may be data representing blood pressure value, AST (GOT), ALT (GPT), γ-GT (γ-GTP), or the like. The status data SD may be identification information assigned to a pattern (for example, a stamp) representing a message or the like that the person wants to convey.

If it is the status data SD of the moving body 1 itself, for example, data such as a fault code representing the occurring malfunction, moving speed, moving direction, oil consumption, simple remaining battery level, degree of battery consumption, air-fuel ratio, etc. can be mentioned. If the mobile object 1 is a car, a DTC (Diagnostic Trouble Code) may be adopted. DTC is a code consisting of alphanumeric characters.

If the status data SD represents the environment in which the mobile body 1 is placed, for example, data such as atmospheric pressure, temperature, humidity, etc. can be cited. Any of the status data SD is just an example, and the status data SD may be determined depending on the type of mobile body 1, its use, etc. For this reason, the state data SD is not particularly limited. Strictly speaking, any data that may change depending on the situation etc. may be used.

The encoding device on the mobile body 1 is realized by installing, for example, an executable encoding program AP1, which is an application program (hereinafter abbreviated as "application"), on the mobile body 1. The position data PD and the status data SD, each of which is a data group, that is, a plurality of data, are separately encoded by the encoding program AP1 and transmitted from the communication module 11.

The encoding program AP1 may be distributed by being recorded on a removable medium, or may be distributed via a network N2, etc., which will be described later. For this reason, the recording medium on which the encoding program AP1 is recorded may be one mounted on or attached to an information processing device directly or indirectly connected to the network N2, etc., or an externally accessible device. It may be installed or attached to. This also applies to the decoding program AP2, which will be described later.

In this embodiment, a decoding device that restores encoded position data PD by decoding is installed in the server 2. The server 2 and the mobile object 1 are capable of communicating via the network N1. A communication module 21 installed in the server 2 enables communication via the network N1.

This server 2 is also connected to network N2. A person who owns or uses the mobile object 1 or who is involved in the management of the mobile object 1 can access the restored position data PD or the like by accessing the information terminal 3 to the server 2 via the network N2. The position represented by the position data PD can be confirmed. The server 2 is equipped with a communication module 22 to enable communication via the network N2.

The decryption device on the server 2 is realized by, for example, installing a decryption program AP2, which is an application, on the server 2 in an executable manner. The encoded position data PD and status data SD received by the communication module 21 are respectively decoded and restored by the decoding program AP2.

The network N2 is a network group including, for example, the Internet, a public telephone network, a mobile phone network, and the like. The information terminal 3 is an information processing device that is connected to, for example, a LAN (Local Area Network) or a mobile phone network, and is capable of communicating with the server 2 via the network N2.

If the mobile body 1 can be connected to a LAN, public telephone network, mobile phone network, etc., the mobile body 1 and the information terminal 3 may communicate directly via the network N2. However, in reality, the area that can be connected to a LAN, public telephone network, mobile phone network, etc. is limited. The reality is that the area that can be connected to LAN, public telephone networks, mobile phone networks, etc. accounts for a very small percentage of Japan as a whole. Therefore, position data PD and the like are transmitted and received between the mobile body 1 and the information terminal 3 via the network N1 and the server 2.

From this, it is assumed that the network N1 is one that enables communication in areas that cannot be covered by the network N2. An example of such a network N1 is an LPWA (Low-Power Wide-Area) network.

Characteristics of communication via an LPWA network include low power consumption, low bit rate, wide area coverage, etc. As a result, when the LPWA network is used as the network N1, areas not covered by the network N2 can be efficiently covered, that is, with a small number of base stations. It is also planned to use artificial satellites such as low-orbit satellites as base stations.

In an LPWA network, the number of bytes that can be stored in the payload is usually relatively small, partly due to the low bit rate. For example, there are communication specifications that limit the payload to 12 bytes for upstream and 8 bytes for downstream. Therefore, in communication via an LPWA network, it is desirable to reduce the amount of data to be transmitted. For this reason, in this embodiment, the moving body 1 is equipped with an encoding device in order to further reduce the amount of data stored in the payload. This allows the encoded position data PD and state data SD to be stored in one payload.

Encoding increases the confidentiality of the data to be encoded. The arrangement of the position data PD and state data SD in the payload, the number of bits assigned to them, the type of data included as the state data SD, etc. are information that does not need to be specifically disclosed to the outside. For example, the state data SD may include data representing the state of the mobile body 1, data representing the environment in which the mobile body 1 is placed, data representing the state of the person moving with the mobile body 1, etc. It is also difficult to identify the type of data. It can be said that most people cannot understand the meaning of the DTC that indicates the status of the mobile object 1 as it is.

For this reason, the decoding program AP2 not only decodes and restores the position data PD and state data SD, but also encodes the restored position data PD and state data SD in a form that is easy for people to understand. The provided functions may also be installed. It may be possible to set the information terminal 3 that can view the provided data, that is, the individual or corporation that uses the information terminal 3, so that only the set information terminal 3 can receive the data.

The restoration of the position data PD and state data SD needs to be compatible with the encoding of the position data PD and state data SD. Therefore, in this embodiment, files that can be used for encoding and decoding are prepared on both the mobile body 1 side and the server 2 side (see FIG. 6). The file may be a file with an intelligent conversion function, for example, a metafile with an AI (Artificial Intelligence) function.

By using such a file, end-to-end encryption of the position data PD and state data SD will be realized. The amount of data stored in the payload can be further reduced, and an LPWA network can also be used. With the availability of LPWA networks, the area that can be covered on earth will become wider. As a result, services for transmitting and receiving position data PD or status data SD can be provided securely, at lower cost, and over a wider range.

FIG. 2 is a diagram showing an example of a circuit configuration of a mobile body equipped with an encoding device according to an embodiment of the present invention.
This moving object 1 is, for example, a drone. As shown in FIG. 2, in addition to the communication module 11, the mobile body 1 includes an FC (Flight Controller) 10, a transmission/reception module 12, a motor group 13, an ESC (Electric Speed Controller) group 14, a touch panel 15, and a camera 16. , and sensor group P.

The transmitter/receiver module 12 is a module that enables communication with a transmitter/receiver (proportional system, abbreviated as "propo" in FIG. 3) for operating the mobile body 1. This transceiver module 12 causes the mobile body 1 to operate according to instructions given by the transceiver.

The motor group 13 is a plurality of motors that each rotate a corresponding rotor (propeller). The ESC group 14 is a plurality of ESCs each driving a corresponding motor.
The touch panel 15 is an input/output device that allows display of various information or instructions.
The camera 16 is a device that captures moving images or still images according to settings. The settings can be made using the touch panel 15.

The sensor group P is various sensors used when the mobile object 1 flies. As shown in FIG. 2, the sensor group P includes a gyro sensor P1, an acceleration sensor P2, a magnetic direction sensor P3, an atmospheric pressure sensor P4, a GNSS (Global Navigation Satellite System) receiving module P5, a ranging module group P6, etc. It will be done.

The gyro sensor P1 is a sensor for measuring the angular velocity of the moving body 1 in each of three axes, for example. The acceleration sensor P2 is a sensor for detecting the posture of the moving body 1 in each of three axes, for example. The magnetic direction sensor P3 is a sensor for detecting the direction in which the moving body 1 is facing.

The atmospheric pressure sensor P4 is a sensor for detecting atmospheric pressure. This atmospheric pressure sensor P4 can also detect the approximate current altitude of the mobile object 1. The GNSS receiving module P5 generates position data PD representing the longitude, latitude, and altitude where the mobile object 1 is located by satellite positioning, that is, by receiving radio waves transmitted from a positioning satellite. The distance measuring module group P6 is a plurality of distance measuring modules for measuring distances to objects that exist in each direction, for example, front and back, left and right, and up and down directions of the moving body 1. The moving body 1 can be moved without coming into contact with other objects by the distance measuring module group P6. Note that each distance measuring module is capable of measuring the distance to an object by emitting ultrasonic waves or laser light, for example.

The FC 10 controls the entire mobile body 1. Processing of instructions received by the transmitting/receiving module 12, communication via the communication module 11, drive control of the motor group 13 via the ESC group 14, input/output via the touch panel 15, control of the camera 16, and communication from the sensor group P. Signal processing and the like are performed by the FC 10. For this purpose, the FC 10 is equipped with a microcontroller 100.

As shown in FIG. 2, this microcontroller (hereinafter abbreviated as "microcomputer") 100 includes a CPU (Central Processing Unit) 101, a flash memory 102, a RAM (Random Access Memory) 103, and an I/F (InterFace) controller. Groups 104 are included and are connected to the bus.

The CPU 101 controls the entire mobile body 1 by reading various programs stored in the flash memory 102 into the RAM 103 and executing them. The various programs include an encoding program AP1 shown in FIG.

The I/F controller group 104 is a plurality of controllers that enable communication with each of the sensors P1 to P6, the ESC group 14, the touch panel 15, and the camera 16 that constitute the sensor group P, for example. The communication module 11 and the transmission/reception module 12 are connected to a bus, like the flash memory 102 and the like.

This I/F controller group 104 allows the CPU 101 to capture and process the signals obtained from each sensor P1 to P6 as data. Further, the camera 16 can be controlled at any time, and the imaging results etc. output from the camera 16 can be stored in the flash memory 102 or the like. By driving the motor group 13 via the ESC group 14, the movable body 1 can be moved.

FIG. 3 is a functional block diagram showing an example of a functional configuration realized on a mobile body equipped with an encoding device according to an embodiment of the present invention. Note that this functional configuration example is just an example, and the functional configuration is not particularly limited.

As shown in FIG. 3, the CPU 101 constituting the microcomputer 100 of the mobile object 1 has an operation recognition section 1001, a screen generation section 1002, an instruction recognition section 1003, a drive control section 1004, and a route registration section 1005, as shown in FIG. , an autopilot unit 1006, a distance measurement unit 1007, a camera control unit 1008, a failure diagnosis unit 1009, an encoding unit 1010, and a setting change unit 1011. In order to realize such functional components on the CPU 101, the flash memory 102 has a common encryption key storage section 1201, a route information storage section 1202, and a setting information storage section 1203 as areas for storing information. is ensured.

The operation recognition unit 1001 recognizes operations performed on the touch panel 15. Other components function depending on this recognition result.
The screen generation unit 1002 generates a screen to be displayed on the touch panel 15. The recognition result of the operation recognition unit 1001 is used for determining whether or not to generate a screen, specifying the type of screen to be generated, and the like.

The instruction recognition unit 1003 recognizes the content of the instruction given by operating the transceiver 5. For recognition, the data received by the transmitting/receiving module 12 and input to the CPU 101 is passed to the instruction recognition unit 1003.

The drive control unit 1004 performs drive control of the motor group 13 via the ESC group 14. For this purpose, the instruction recognition result by the instruction recognition unit 1003 is passed to the drive control unit 1004. Further, for posture control and the like, information such as the rotational speed of each motor constituting the motor group 13, digital data of signals from the gyro sensor P1, the acceleration sensor P2, etc., are also passed to the drive control unit 1004.

The route registration unit 1005 corresponds to the registration of a route along which the mobile body 1 should move autonomously. Information representing the registered route is stored as route information in the route information storage unit 1202 secured in the flash memory 102. For route registration, an operation recognition unit 1001 and a screen generation unit 1002 also function to provide a necessary UI (user interface).

The autopilot unit 1006 enables the mobile body 1 to autonomously move along the route represented by the route information stored in the route information storage unit 1202. Actual movement is realized under the control of the drive control unit 1004. To enable movement along the route, position data PD output from the GNSS receiving module P5 from time to time is used. Autopilot using the position data PD allows the mobile device 1 to move along the route represented by the route information. Thereby, the automatic machine 1 can be used for various investigations, various measurements, delivery of products, etc. in areas where communication with the transceiver 5 is impossible.

The distance measurement unit 1007 processes data output from each distance measurement module that constitutes the distance measurement module group P6, for example, and measures (calculates) distances to objects that exist in each of the front and back, left and right, and up and down directions. do. This measurement result is passed to the drive control section 1004 or the autopilot section 1006. Thereby, the moving body 1 is autonomously controlled so as not to come into contact with the object.

The camera control unit 1008 controls the camera 16 and causes the camera 16 to capture moving images or still images as necessary. It corresponds to the storage of a captured moving image or still image in the flash memory 102 and the transmission of the moving image to the transceiver 5 via the transmitting/receiving module 12. Thereby, the person operating the transceiver 5 can check the image captured by the camera 16 on the condition that the transceiver 5 is located within the range where the transceiver module 12 can communicate.

The failure diagnosis unit 1009 performs diagnosis to detect failures including defects that occur in the mobile body 1. When a failure is detected, information representing the failure, such as a failure code, is identified and stored in, for example, the flash memory 102. The failure code is data corresponding to the status data SD.

The encoding unit 1010 encodes the position data PD output from the GNSS receiving module P5, and transmits the encoded position data PD via the communication module 11. Encoding of the position data PD is performed with reference to a group of common encryption keys stored in the common encryption key storage unit 1201 secured in the flash memory 102. Details of the encoding including the common encryption key will be described later. This encoding unit 1010 also encodes the state data SD separately from the encoding of the position data PD.

The data to be encoded is ultimately determined by the encoding unit 1010. For this reason, the encoding unit 1010 corresponds to all of the data acquisition means, space identification means, and encoding means in this embodiment. The setting change unit 1011 corresponds to a setting means. The data to be encoded also includes various status data SD generated by the failure diagnosis unit 1009 and the like.

The setting change unit 1011 corresponds to setting changes in encoding of the position data PD by the encoding unit 1010. A setting information storage section 1203 secured in the flash memory 102 is used to store setting information representing the setting contents. Details of the settings will also be described later.

As described above, the mobile object 1 is a flying object, such as a drone, that can be controlled by the transceiver 5. In this embodiment, it is also assumed that the mobile object 1 is caused to move (fly) to a place where communication with the transceiver 5 is not possible. For this reason, the position of the mobile object 1 can be confirmed using communication via the network N1. Here, it is assumed that the user terminal 6 confirms the position of the mobile object 1, in other words, the user terminal 6 is the destination of the encoded position data PD. Thereby, this user terminal 6 becomes an information processing device that realizes a decoding device by executing the decoding program AP2 shown in FIG.

The user terminal 6 itself is an information processing device used by the person who operates the transceiver 5 or by a person related to the person. The information processing device is not particularly limited, but in FIG. 3, a tablet PC (Personal Computer) or the like capable of communication via the network N1 is assumed.

As shown in FIG. 3, the user terminal 6 includes a communication module 61, a CPU 62, a flash memory 63, and a touch panel 64.
The communication module 61 is a module that enables communication via the network N1. A common encryption key storage section 631 is secured in the flash memory 63, as in the mobile body 1. The contents of the common encryption key group stored in the common encryption key storage section 631 are also the same as those of the mobile body 1. The "common" in the common encryption key represents this.

The decryption program AP2 is stored in the flash memory 63, for example. By executing this decoding program AP2, a bit data restoring section 621, a decoding section 622, and a setting changing section 623 are implemented on the CPU 62 as a functional configuration. Details of each function of the bit data restoration section 621, decoding section 622, and setting changing section 623 will be described later.

For the user terminal 6 as a whole, encoded data is acquired by the communication module 61. Therefore, it can be said that the communication module 61 corresponds to the information acquisition means in this embodiment. However, if the encoded data is divided, the bit data restoring unit 621 is also required. From this, it can be said that the bit data restoration section 621 also corresponds to information acquisition means. The decoding unit 622 corresponds to both the data specifying means and the output means.

FIG. 4 is a diagram illustrating an example of an encoding method adopted by an encoding device according to an embodiment of the present invention. This encoding method is based on the assumption that position data PD is composed of longitude data, latitude data, and altitude data.

It is normal for the position data PD obtained by satellite positioning to have some degree of error. Examples of such errors include satellite clock errors, satellite orbit errors, ionospheric delay errors, and tropospheric delay errors. The total error depends on the sum of these errors. Due to the presence of such errors, the actual number of digits that are valid for each of the longitude data, latitude data, and altitude data changes.

Further, the accuracy required for the position data PD usually differs depending on the type, size, purpose, etc. of the moving body 1. For example, in large passenger planes, large ships such as tankers, etc., accuracy in meters is usually not required due to their size. Ships, automobiles, people, etc. are usually located at the sea surface or the ground surface, so there is no need to particularly consider altitude. Due to such precision requirements, the number of digits actually required for each of the longitude data, latitude data, and altitude data varies. Altitude data may not be necessary.

In this way, the number of digits actually required for each of the longitude data, latitude data, and altitude data changes depending on the error, required accuracy, etc. The smaller the number of digits, the more the amount of data can be reduced. In this embodiment, the space in which the position can be indicated by the position data PD is virtually quantized, that is, divided, in order to be able to cope with changes in the number of digits required. The minimum space used for this quantization is the unit space. A space whose position can be indicated by the position data PD will be hereinafter referred to as a "whole space" in order to more clearly distinguish it from a unit space. The top diagram in FIG. 4 represents an example of a method of dividing the entire space into unit spaces. Note that the overall space here is a three-dimensional space, but since the overall space itself is intended to encode a plurality of data, it may be a multidimensional space having two or more dimensions.

In this embodiment, a mesh number is assigned as identification information to each unit space in accordance with the quantization of the entire space. Thereby, the unit space including the position indicated by the position data PD is specified from the position data PD, and the position data PD is converted into a mesh number assigned to the specified unit space. In order to enable conversion into a mesh number, in addition to the mesh number, each unit space is also assigned, for example, a range of position data PD associated with that unit space. In reality, the range of the position data PD is treated as the range or shape of a unit space, and the mesh number is assigned to the range of the position data PD.

Mesh numbers can be assigned to unit spaces arbitrarily. The mesh number itself is data different from the position data PD. Therefore, converting the position data PD into a mesh number is not only encoding of the position data PD but also encryption. This mesh number is also used to decode the position data PD. For this reason, the mesh number serves as a common encryption key.

There is one position data PD that is associated with a mesh number. One of the position data PD may be calculated from the range of the position data PD, but it may also be prepared separately from data indicating the range of the position data PD. One of the position data PD may be obtained in different ways depending on the assumed unit space. For example, in a unit space that includes or touches the sea surface or the ground surface, the height of the sea surface or the ground surface may be used as the altitude data, and in other unit spaces, the intermediate height may be used as the altitude data. Because of this, there are no particular limitations on how to set one piece of position data PD. Note that one piece of position data PD associated with a unit space will be hereinafter referred to as "representative position data PD" in order to distinguish it from the others.

FIG. 5 is a diagram illustrating an example of quantization of the entire space. In FIG. 5, the height scale and maximum error represent the size of a unit space for quantizing the entire space. The target example is an example of a moving body 1 assumed to have a size of a corresponding unit space.

The height scale here refers to the number of divisions of a predetermined height range. Therefore, for example, if the height range is 0 to 10,000 meters and the height scale is 1000, the height of the unit space is 10 meters. When the height scale is 1, the unit space is treated as an area above the sea level or the ground surface. In this case altitude data is ignored.

The maximum error is, for example, an index defined as the length from the center of the unit space to the edge with the maximum distance in the horizontal direction. If the shape of the horizontal plane of the unit space is rectangular, the edge with the maximum distance will be all four corners or one or more corners. If the rectangle is, for example, a square with one side of approximately 11 m, the maximum error will be approximately 7 m, and the edges with the maximum error will be the four corners.

In FIG. 5, six unit space sizes are shown as examples. However, the size of the unit space is not particularly limited. Moreover, the shape is not particularly limited either. The target examples are also shown as representative examples assuming unit spaces of various sizes, and the relationship between the size of the unit space and the target examples is not particularly limited.

The correspondence between the position data PD and the unit space changes depending on the size of the unit space as shown in FIG. For this reason, in this embodiment, the size of the unit space can be arbitrarily selected as a setting for encoding the position data PD. The setting change unit 1011 shown in FIG. 3 is a function that allows the size of such a unit space to be changed as a setting. The setting information stored in the setting information storage unit 1203 is information representing the size of the unit space, that is, the content of quantization of the entire space.

The position data PD decoding side must decode the position data PD according to the size of the unit space used during encoding. Therefore, as shown in FIG. 3, the setting change unit 623 is also implemented on the CPU 62 installed in the user terminal 6. The setting information is stored in the flash memory 63, for example. Since the decoding side cannot properly restore the position data PD unless the decoding side matches the settings of the encoding side, making the settings changeable is useful in realizing higher confidentiality of the position data PD.

The amount of data required to encode the position data PD by quantizing the entire space as described above, that is, the amount of data required to express the encoded position data PD is as follows. Here, a unit space with a standard height scale of 650 and a maximum error of about 7 m will be explained as an example. For ease of understanding, the entire space is assumed to be a rectangular parallelepiped section for convenience. Accordingly, the shape of the horizontal plane of the unit space is assumed to be a square with one side of 7 m.

First, the surface area of the earth is: Surface area of the earth≒510×10 ⁶ [km ² ]=510×10 ¹² [m ² ]
It is.
Assuming that this surface area is rectangular, and dividing it into square areas with sides of 11 m, the total number of areas will be: Total number of areas = 510 x 10 ¹² /121 ≒ 421 x 10 ¹⁰
becomes.

Assuming that this area is a block with a certain height, and 650 blocks are stacked vertically (if the expected height range is divided into 650), the total number of blocks will be: Total number of blocks ≒ 421 × 10 ¹⁰ × 650=274×10 ¹³
becomes. This total number of blocks is the total number of unit spaces.

Dividing this total number by 256 ⁶ (total number of numbers that can be expressed in 6 bytes) gives 274×10 ¹³ /256 ⁶ ≒9.73
becomes. Therefore, in order to express it in binary numbers, that is, binary data, in addition to 6 bytes, 10 in decimal number (the number of integers from 0 to 9) is required. In other words, four or more bits are required to express it as binary data. Therefore, the minimum number of bits required to express it as binary data is 6 bytes + 1 byte (minimum is 4 bits).

FIG. 4 shows that N bits + M bytes of data are generated by converting the mesh number into binary data. In the above example, N is an integer between 4 and 8, and M is an integer of 6 or more. 4 is the minimum value of N, and 6 is the minimum value of M.

Such values of N and M are three-dimensional data, and are realized as a result of a dimensional conversion operation from three dimensions to one dimension of position data PD composed of three data. This dimension conversion operation avoids the need to treat each of the three pieces of data separately and eliminates or minimizes redundancy. As a result, the amount of data can be reduced, and reversible data compression is also possible. Since the data is compressed by dimensional conversion, it will also be encrypted.

In this embodiment, it is assumed that position data PD after encoding is transmitted. Therefore, in this embodiment, M bytes of data are transmitted as encoded data of the position data PD, and the most significant N bits are used as control data for transmitting the encoded data. Therefore, here, the M-byte data corresponds to the first data, and the N-bit data corresponds to the second data. Note that binary data may be transmitted as the M+1 byte encoded data.

In order to make it possible to use N-bit data as control data for transmission, in this embodiment, a predetermined unit time is divided, and each time width obtained by the division is used for communication of encoded data. The time slots TS (TS1 to TSk) are the communication resources for. Thereby, as shown in FIG. 4, the N-bit control data is used for selecting a communication resource, that is, a time slot TS, and encoded data is transmitted in the selected time slot TS.

Specifically, for example, when representing decimal numbers 0 to 9 with N-bit data as described above, ten time slots TS1 to TS10 (k=10) are prepared as time slots TS. As a result, if the N-bit data represents 9 in decimal notation, time slot TS10, for example, is selected as time slot TS for transmitting 6-byte data. If the N-bit data represents 0 in decimal notation, time slot TS1, for example, is selected as time slot TS for transmitting 6-byte data. Through such selection of time slots TS, N-bit data can be expressed.

As a result, for example, when transmitting encoded data of position data PD according to a communication specification (communication standard) in which the payload is 12 bytes, it is possible to transmit 6 bytes of data at once in addition to the encoded data. . Note that the position of the N-bit data used for selecting the time slot TS on the binary data may be arbitrary. The N-bit data does not have to be continuous. In other words, the N-bit data may be distributed at multiple locations. This is because by determining the position in advance, the restored N-bit data can be inserted into that position.

The time slot TS used for transmitting encoded data can also be recognized on the receiving side. This is because the unit time, the number of time slots TS, the time width of each time slot TS, and the start time of each unit time can be treated as common settings in advance. Thereby, the decoding side can restore N-bit control data from the timing when the encoded data is received. Therefore, the decoding side can restore binary data composed of N bits of control data and M bytes of encoded data.

The restored binary data is the mesh number converted into a binary number. Therefore, after the binary data is restored, the decimal mesh number represented by the binary data is restored, and the unit space to which the mesh number is assigned is specified. By specifying the unit space, representative position data PD associated with the unit space is further specified. By specifying the representative position data PD, decoding is completed, and the specified representative position data PD is treated as restored position data PD.

The user terminal 6 shown in FIG. 3 marks the position represented by the position data PD restored in this way on a map or a topographic map displayed on the touch panel 64 using data stored in advance in the flash memory 63, for example. etc. to display it. Thereby, the user using the user terminal 6 can confirm the location of the mobile device 1. Note that the user who uses the user terminal 6 may be the same person as the user who operates the transceiver 5, or may be a different person.

By encoding the position data PD, the amount of data transmitted and received can be suppressed. For this reason, even if communication between the mobile unit 1 and the user terminal 6 is possible via a communication network such as an LPWA network where data transmission and reception are not restricted, such as a mobile phone network, the code of the position data PD is It may also be possible to perform Accordingly, the communication network used for transmitting and receiving data is not particularly limited. Further, the position data PD may be encoded in order to store the data in a recording medium. For example, in the moving object 1, the encoded position data PD may be stored in the flash memory 102, so that the actual moving route of the moving object 1 can be confirmed.

Regardless of the application, the data necessary for decoding can be prepared in advance on the decoding side, thereby avoiding the need to acquire data for decoding at any time. Therefore, there are few restrictions on the use of data encoding and decoding, and the versatility is extremely high. The data is not limited to position data PD, but can be applied to multiple data, in other words, each data needs to be one-dimensional data, so the scope of application of the data is very wide. Become.

FIG. 6 is a flowchart showing an example of each flow of encoding processing and decoding processing. The two flowcharts are based on the assumption that the position data PD is encoded as shown in FIG. The CPU 101 is assumed to be the entity that performs the encoding process, and the CPU 62 is assumed to be the entity that performs the decoding process. The encoding process is realized by the CPU 101 executing the encoding program AP1, and the decoding process is realized by the CPU 62 executing the decoding program AP2.

The GNSS receiving module P5 performs satellite positioning at time intervals set by the CPU 101, for example, and outputs position data PD obtained as a result. In such a case, the encoding process is triggered by the output of the position data PD of the GNSS receiving module P5. It is assumed that various settings including the size of the unit space are made in advance. Based on this assumption, the common encryption key group 7 is shown as data that is referred to on the encoding side and the decoding side depending on the setting. This common encryption key group 7 only corresponds to one setting, and for example, as described above, the range of the corresponding unit space and the representative position data PD are associated with each mesh number that is the common encryption key. ing. The common encryption key storage unit 1201 stores a settable number of such common encryption key groups 7. Note that the settings may include the amount of encoded data. Since there are various communication specifications, it is desirable to make the amount of encoded data configurable. The common encryption key group 7 may be automatically created to avoid the need to prepare it as data in advance.

First, in step S1, the CPU 101 acquires the position data PD output from the GNSS receiving module P5. In the next step S2, the CPU 101 refers to the common encryption key group 7, specifies the mesh number of the unit space corresponding to the acquired position data PD, and replaces the position data PD with the specified mesh number.

In the subsequent step S3, the CPU 101 converts the mesh number into binary data. In the following step S4, the CPU 101 determines whether a division setting (see FIG. 4) has been made in which the binary data is divided and one part is used to control the transmission timing of the remaining part. If the division setting has been made, the determination in step S4 is YES and the process moves to step S5. If the division setting has not been made, the determination in step S4 is NO, and the encoding process ends here. Thereby, the binary data obtained in step S3 will be transmitted as encoded data.

In step S5, the CPU 101 divides the binary data. After that, the encoding process ends. By dividing the binary data, one part is used to select a time slot TS for controlling the remaining transmission timing, and the remaining part is transmitted in the selected time slot TS.
In the encoding process, the above-mentioned process is executed. Thereby, as shown in FIG. 4, the position data PD is encoded, and the encoded data is transmitted using the time slot TS as a communication resource, if necessary.

On the other hand, the decoding process is started, for example, by receiving encoded data.
First, in step S11, the CPU 62 acquires, in addition to the binary data received as encoded data, the reception timing of the binary data, for example, data on the reception date and time. In the following step S12, the CPU 62 determines whether or not division settings have been made. If the division setting has been made, the determination in step S12 is YES and the process moves to step S13. If the division setting has not been made, the determination in step S12 is NO and the process moves to step S14.

In step S13, the CPU 62 converts the reception timing into data. As a result, in the example shown in FIG. 4, N bits of data are restored. As a result of this restoration, the process moves to step S14 in a state where binary data obtained by converting the mesh number, that is, complete binary data exists. If the transition is made with a NO determination in step S12, it means that complete binary data has been acquired in step S11.

In step S14, the CPU 62 restores the mesh number from the binary data. In the subsequent step S15, the CPU 62 refers to the common encryption key group 7, identifies the representative position data PD of the unit space corresponding to the restored mesh number, and decodes the identified representative position data PD with the decrypted position data PD. By doing so, the position data PD is restored. After that, the decoding process ends.

As described above, the restored position data PD includes errors in the vertical direction according to the height scale and errors within the maximum error in the horizontal direction. However, by selecting an appropriate unit space size, the position data PD can be encoded and decoded virtually without any problems. Even if the position data PD output by the GNSS receiving module P5 is encoded without reducing accuracy, the encoded data can be stored in a 12-byte payload with plenty of room.

If the accuracy is not reduced, the representative position data PD of the unit space associated with the position data PD may represent the position of a point specified by each value of longitude data, latitude data, and altitude data. In this case, the unit space is simply used for dimensional conversion operations on three data: longitude data, latitude data, and altitude data. Data compression is losslessly and reversibly encoded.

Since the unit space is used for such purposes, the number of data to be encoded at once, that is, the number of dimensions, need only be two or more. Thereby, a plurality of data may be collectively encoded as state data SD. In this embodiment, by encoding a plurality of pieces of data as state data SD separately from position data PD, it is possible to transmit more data at one time.

The shape of the unit space is basically determined according to the number of dimensions, and the size of the unit space can be determined according to the required accuracy, etc. As a result, the amount of encoded data can be suppressed to a value corresponding to the multiplication result obtained by multiplying the number of values to be expressed by each piece of data.

In this embodiment, the settings for encoding are fixed. In other words, settings cannot be changed when encoding is performed. However, the settings may be changed in a situation where encoding is performed. Settings may be changed according to instructions from a person or according to a schedule, or may be changed autonomously.

For example, in the case of a flying moving object 1, the permissible error in the horizontal direction usually changes depending on the altitude. For example, the closer the moving object 1 is to the sea surface or the ground surface, the smaller the allowable error in the horizontal direction tends to be. This tendency is particularly strong when the moving body 1 is moved toward a destination or a target location on the sea surface or the ground surface. In view of this, the settings may be autonomously changed so that the closer the moving object 1 is to the sea surface or the ground surface, the smaller the maximum error in the horizontal direction becomes. Such an autonomous setting change is based on, for example, the distance to an object below the moving body 1 measured by the distance measuring unit 1007, and/or the altitude expected from the atmospheric pressure measured by the atmospheric pressure sensor P4, etc. The setting change unit 1011 may be made to do this.

When enabling autonomous setting changes, it is necessary to enable the decoding side to recognize the settings at the time of encoding. As shown in FIG. 5, when one of the six settings is selected, data of 3 bits or more is required in order to make the setting recognizable on the decoding side. The 3-bit data may be transmitted as 1-byte data together with the N-bit data. Even if data representing the settings is added, the total amount of data can be kept to 7 bytes, so in a 12-byte payload, 5 bytes can be allocated for transmitting other data. The autonomous setting change may be made in accordance with the speed of the moving body 1, the topography of the area in which the moving body 1 moves, and the like.

In this embodiment, the amount of encoded data to be transmitted is fixed. However, the amount of data may be changed depending on the combination of height scale and maximum error. Alternatively, combinations of height scales and maximum errors that can be combined may be presented according to the specified amount of data, and the user may be allowed to select a desired combination from the presented combinations. The target examples may be presented and the user may be allowed to select an assumed moving object from among the presented target examples.

1 Mobile object, 2 Server, 3 Information terminal, 5 Transmitter/receiver, 6 User terminal, 7 Common encryption key group, 10 FC, 11, 21, 22, 61 Communication module, 62, 101 CPU, 63, 102 Flash memory, 631 Bit data restoration unit, 632 Decoding unit, 623, 1011 Setting change unit, Drive control unit 1004, Route registration unit, 1005 Autopilot unit, 1007 Distance measurement unit, 1010 Encoding unit, 1201 Common encryption key storage unit, AP1 code program, AP2 decoding program, N1, N2 network, P sensor group, P5 GNSS reception module, P6 ranging module group.

Claims

a data acquisition means for acquiring a plurality of data to be encoded;
By regarding each data constituting the plurality of data acquired by the data acquisition means as one-dimensional data, the number of data constituting the plurality of data is taken as the number of dimensions, and multidimensional data corresponding to the number of dimensions is assumed. space specifying means for specifying the unit space corresponding to the plurality of data from among the unit spaces that virtually divide the space;
encoding means for outputting identification information assigned to the unit space specified by the space specifying means as encoded data of the plurality of data;
An encoding device comprising:
When the data acquisition means acquires position data indicating a position on the earth using at least longitude data and latitude data obtained by satellite positioning as the plurality of data, the spatial specifying means acquires the position data indicating the position on the earth using at least longitude data and latitude data. identifying the unit space by assuming that the position data is the plurality of data by considering at least each of the latitude data as the one-dimensional data;
The encoding device according to claim 1.
The data acquisition means acquires the position data including only the longitude data and the latitude data as the plurality of data,
The space specifying means sets the number of dimensions to 2, sets the multidimensional space as a two-dimensional plane, and sets an area that virtually divides the two-dimensional plane as the unit space, and identifies a plurality of areas existing on the two-dimensional plane. identifying an area corresponding to the longitude data and the latitude data,
The encoding means outputs identification information of the area specified by the space specifying means as the encoded data.
The encoding device according to claim 2.
The data acquisition means acquires the position data including the longitude data, the latitude data, and the altitude data as the plurality of data,
The space specifying means sets the number of dimensions to three, sets the multidimensional space as a three-dimensional space, and sets a hexahedron that virtually divides the three-dimensional space as the unit space, and identifies a plurality of objects existing in the three-dimensional space. Identifying a hexahedron corresponding to the longitude data, the latitude data, and the altitude data from among the hexahedrons,
The encoding means outputs identification information of the hexahedron identified by the space identifying means as the encoded data.
The encoding device according to claim 2.
further comprising a setting means for setting a shape including the size of the unit space,
The space specifying means specifies the unit space corresponding to the plurality of data, assuming the unit space having the shape set by the setting means.
The encoding device according to claim 1.
When outputting the encoded data for transmission, the encoding means outputs the encoded data separately into first data and second data, thereby converting the first data into the first data. Transmit at the transmission timing controlled by the data in 2.
The encoding device according to any one of claims 1 to 5.
Information acquisition means for acquiring the identification information output as the encoded data by the encoding device according to any one of claims 1 to 6;
data identifying means for identifying the unit space to which the identification information acquired by the information acquiring means is assigned, and further identifying the plurality of data associated with the identified unit space;
output means for outputting the plurality of data specified by the data specifying means as decoded data;
A decoding device comprising: