JP7468904B2 - Information management method and vehicle operation history management device - Google Patents

Description

This disclosure relates to an information management method and a vehicle operation history management device.

2. Description of the Related Art There are known in-vehicle devices that are mounted on vehicles and used in such vehicles, and some of these in-vehicle devices include a GPS (Global Positioning System) receiver for receiving position information.
Such an in-vehicle device may be used, for example, as a vehicle operation history management device. The vehicle operation history management device has a function of storing vehicle position history information (hereinafter also referred to as GPS log data) related to the route of vehicle operation using position information (hereinafter also referred to as GPS data) received from a GPS satellite.

The in-vehicle device stores GPS log data including multiple GPS data by recording the GPS data in an internal recording unit (e.g., an internal memory, etc.) of the in-vehicle device. The in-vehicle device can also transmit the GPS log data in the internal recording unit to an external device (e.g., a server device, etc.) by data uploading using a wireless communication network, and store the GPS log data in the external device. This allows the user of the in-vehicle device to check the vehicle driving route after the fact based on the GPS log data in the external device, even if the GPS log data is deleted from the in-vehicle device.

By increasing the recording density of the GPS data recorded as GPS log data (in other words, by shortening the period during which GPS data is acquired), the vehicle route can be recorded in more detail. However, as the recording density of the GPS log data increases, the amount of data per unit time increases, and the maximum time for which the vehicle route can be recorded in the internal recording unit becomes shorter.

In response to this, a technology has been proposed that extends the maximum time for which vehicle travel routes can be stored by lowering the recording density of GPS log data when the GPS log data has been recorded up to the capacity limit of the internal recording unit (Patent Document 1). Specifically, in the GPS log data recorded in the internal recording unit, a process of thinning out (deleting) one GPS data for every two GPS data is performed to ensure free space in the internal recording unit. After that, one GPS data is recorded every time two GPS data are acquired. Note that lowering the recording density of GPS log data corresponds to lengthening the acquisition cycle of GPS data, in other words.

Japanese Patent Application Laid-Open No. 4-369682

However, when the recording density of the GPS log data recorded in the internal recording section is changed, management of the GPS log data may become complicated.
That is, for example, in order to change the recording density of the GPS log data to a lower value, some GPS data in the multiple recording areas may be deleted, resulting in multiple recording areas corresponding to a series of GPS log data being in a dispersed state. In this case, if the recording locations (in other words, the recording order) of the series of GPS log data in the multiple recording areas are changed randomly (irregularly), the management of the GPS log data may become complicated.

Alternatively, when rearranging multiple recording areas corresponding to a series of GPS log data from a discrete state to a continuous state, the process of moving the multiple GPS data in the recording area of the internal recording unit (in other words, the rearrangement process) may become complicated. In this case, the time required for the process of moving the multiple GPS data may become long. Also, it may be necessary to increase the size of the working area (primary data recording area) required for the movement process.

Therefore, it is desirable for the present disclosure to provide an information management method and a vehicle operation history management device that can prevent the management of vehicle position history information from becoming complicated when changing the recording density of vehicle position history information that includes multiple pieces of position information.

A method according to one aspect of the present disclosure is an information management method for managing vehicle location history information. The information management method includes a location information acquisition step, an initial setting step, a first recording step, a first index change step, and a second recording step.

The vehicle position history information is location information that indicates the vehicle position. The vehicle position history information includes multiple pieces of location information at different times. Furthermore, the vehicle position history information is information recorded in a recording area.

The recording area includes a position information area and an index area.
The location information area includes a plurality of information frames configured to record the vehicle location history information. The plurality of information frames include M information frames arranged consecutively from a 0th information frame to an (M-1)th information frame. The 0th information frame to the (M-1)th information frame are each assigned an individual frame number. The M is an integer equal to or greater than 2 and is a value corresponding to a power of 2. The 0th information frame to the (M-1)th information frame may each be assigned an individual frame number. For example, the 0th information frame to the (M-1)th information frame may each be assigned a frame number from 0 to (M-1). Alternatively, the 0th information frame to the (M-1)th information frame may each be assigned M consecutive frame numbers whose starting point is a number other than 0. Examples of M consecutive frame numbers whose starting point is a number other than 0 include a plurality of frame numbers from 1 to M and a plurality of frame numbers from 2 to (M+1).

The index area includes a plurality of index frames. The plurality of index frames are configured to record reference order information. The reference order information represents the reference order in the plurality of information frames.

The plurality of index frames includes M index frames arranged consecutively from a first index frame to an Mth index frame. Each of the plurality of index frames is configured to record the frame number of each of the 0th information frame to the (M-1)th information frame from the first index frame to the Mth index frame.

The reference order information is determined based on the order of the frame numbers recorded from the 0th information frame to the (M-1)th information frame.
In the position information acquiring step, the position information is acquired for each predetermined first period in a first section spanning a predetermined basic acquisition time.

In the initial setting step, the frame numbers corresponding to the 0th information frame through the (M-1)th information frame are recorded in the 1st index frame through the Mth index frame in that order.

In the first recording step, the position information is recorded for each first period in the first section from the 0th information frame to the (M-1)th information frame based on the reference order information recorded in the initial setting step. In the first recording step, the position information acquired in the position information acquisition step is recorded in each of the 0th information frame to the (M-1)th information frame.

In the first index change step, the reference order information of the index area is changed for a second section following the first section. In the first index change step, the frame numbers corresponding to the position information that is recorded and retains its record even after the reference order information is changed among the recorded position information are recorded in order from the first index frame to each of the (M/2)th index frames. In the first index change step, the frame numbers corresponding to the position information that is recorded and retains its record but not after the reference order information is changed among the recorded position information are recorded in order from the ((M/2)+1)th index frame to each of the Mth index frames.

In the second recording step, the position information is recorded in the information frame for each second period in the second section based on the reference order information recorded in the first index change step. The second period is twice the first period. In the second recording step, the position information is recorded in the information frame corresponding to the frame number according to the order of the frame numbers recorded from the ((M/2)+1) index frame to the M index frame.

In this information management method, when the recording section of the location information transitions from the first section to the second section, there is no need to perform a process of moving (in other words, a process of rearranging) the location information recorded in the information frame in the location information area.

Therefore, the information management method can prevent the management of vehicle position history information in the position information area from becoming complicated when changing the recording density of the vehicle position history information (in other words, changing the acquisition period of the position information).

In addition, the information management method does not require the process of moving multiple pieces of location information when changing the recording density of vehicle position history information. Therefore, the information management method can prevent the time required for the process of moving multiple pieces of location information from increasing. In addition, the information management method can prevent the working area (primary data recording area) required for the process of moving location information from becoming large.

The reference order information is specified by the entire frame numbers recorded in each of the multiple index frames.
Next, in the first index changing step, for each of the first index frame to the (M/2)th index frame, the frame number recorded in the ((n×2)−1)th index frame at the completion of the first recording step may be recorded in the nth index frame. In the first index changing step, further, for each of the ((M/2)+1)th index frame to the Mth index frame, the frame number recorded in the ((k×2)−M)th index frame at the completion of the first recording step may be recorded in the kth index frame. The n is an integer from 1 to M/2, and the k is an integer from (M/2+1) to M.

The process of changing the frame numbers in a plurality of index frames in this manner is an example of how to achieve the first index changing step.
The above-mentioned information management method may include a second index changing step and a third recording step.

In the second index change step, the reference order information of the index area is changed for the third and fourth sections following the second section. In the second index change step, the frame numbers corresponding to the position information that is recorded and retains its record even after the reference order information is changed among the recorded position information are recorded in order in each of the first index frame to the (M/2)th index frame. In the second index change step, the frame numbers corresponding to the position information that is recorded and retains its record but not retained after the reference order information is changed among the recorded position information are recorded in order in each of the ((M/2)+1)th index frame to the Mth index frame.

In the third recording step, the position information is recorded in the information frame for each third period in the third and fourth sections, based on the reference order information recorded in the second index change step. The third period is twice the second period. In the third recording step, the position information is recorded in the information frame corresponding to the frame number according to the order of the frame numbers recorded from the ((M/2)+1) index frame to the M index frame.

This information management method allows vehicle location history information to be recorded for a longer period of time. This makes it possible to record vehicle locations for a longer period of time even when the size of the recording area is limited.

This information management method can further prevent the management of vehicle position history information from becoming complicated when the recording section of the position information transitions from the second section to the third section. The information management method can also prevent the time required for the movement processing of multiple pieces of position information from becoming longer when the recording section of the position information transitions from the second section to the third section. The information management method can also prevent the working area required for the movement processing of the position information from becoming larger.

In the second index change step, the frame number recorded in the ((n×2)-1)th index frame at the completion of the second recording step may be recorded in the nth index frame for each of the first index frame to the (M/2)th index frame. In the second index change step, the frame number recorded in the ((k×2)-M)th index frame at the completion of the second recording step may further be recorded in the kth index frame for each of the ((M/2)+1)th index frame to the Mth index frame. The n is an integer from 1 to M/2, and the k is an integer from (M/2+1) to M.

The process of changing the frame numbers in a plurality of index frames in this manner is an example of how to realize the second index changing step.
The data capacity that can be recorded in the information frame may be larger than the data capacity that can be recorded in the index frame.

When the recording capacity of an information frame is large, rearranging the position information recorded in multiple information frames requires a larger working area, which may result in longer processing times. In contrast, the information management method described above eliminates the need to rearrange the position information recorded in multiple information frames, allowing for quick expansion of free space in the recording area.

In another aspect of the present disclosure, a vehicle operation history management device includes a recording unit and a recording control unit. The recording unit includes a recording area for recording vehicle position history information. The recording control unit is configured to record the vehicle position history information in the recording area.

The vehicle position history information is position information that indicates a vehicle position. The vehicle position history information includes a plurality of pieces of the position information at different times.
The recording area includes a position information area and an index area.

The location information area includes a plurality of information frames configured to record the vehicle location history information. The plurality of information frames include M information frames arranged consecutively from the 0th information frame to the (M-1)th information frame. The 0th information frame to the (M-1)th information frame are each assigned an individual frame number. The M is an integer equal to or greater than 2 and is a value corresponding to a power of 2. The 0th information frame to the (M-1)th information frame may each be assigned an individual frame number. For example, the 0th information frame to the (M-1)th information frame may each be assigned a frame number from 0 to (M-1). Alternatively, the 0th information frame to the (M-1)th information frame may each be assigned M consecutive frame numbers whose starting point is a number other than 0. Examples of M consecutive frame numbers whose starting point is a number other than 0 include a plurality of frame numbers from 1 to M, and a plurality of frame numbers from 2 to (M+1).

The index area includes a plurality of index frames. The plurality of index frames are configured to record reference order information. The reference order information represents the reference order in the plurality of information frames.

The plurality of index frames includes M index frames arranged consecutively from a first index frame to an Mth index frame. Each of the plurality of index frames is configured to record the frame number of each of the 0th information frame to the (M-1)th information frame from the first index frame to the Mth index frame.

The reference order information is determined based on the order of the frame numbers recorded from the 0th information frame to the (M-1)th information frame.
The recording control unit includes a position information acquisition unit, an initial setting unit, a first recording processing unit, a first index changing unit, and a second recording processing unit.

The position information acquisition unit is configured to acquire the position information for each predetermined first period in a first interval spanning a predetermined basic acquisition time.
The initial setting unit is configured to record the frame numbers corresponding to the 0th information frame to the (M-1)th information frame, respectively, in the 1st index frame to the Mth index frame, respectively, in that order.

The first recording processing unit is configured to record the position information from the 0th information frame to the (M-1)th information frame based on the reference order information recorded by the initial setting unit for each of the first cycles in the first section. The first recording processing unit is configured to record the position information acquired by the position information acquisition unit in each of the 0th information frame to the (M-1)th information frame.

The first index change unit is configured to change the reference order information of the index area for a second section following the first section. The first index change unit records the frame numbers corresponding to the position information that will retain its record even after the reference order information is changed among the recorded position information, in each of the first index frame to the (M/2)th index frame in order. The first index change unit records the frame numbers corresponding to the position information that will not retain its record after the reference order information is changed among the recorded position information, in each of the ((M/2)+1)th index frame to the Mth index frame in order.

The second recording processing unit is configured to record the position information in the information frame based on the reference order information recorded by the first index changing unit for each second period, which is twice the first period, in the second section. The second recording processing unit records the position information in the information frame corresponding to the frame number according to the order of the frame numbers recorded from the ((M/2)+1) index frame to the M index frame.

This vehicle operation history management device achieves the same effect as the above-mentioned information management method. In other words, this vehicle operation history management device can prevent the management of vehicle position history information in the position information area from becoming complicated when changing the recording density of the vehicle position history information (in other words, changing the period for acquiring the position information).

In addition, this vehicle operation history management device eliminates the need to move multiple pieces of location information when changing the recording density of vehicle position history information, which makes it possible to prevent the time required for the process of moving multiple pieces of location information from increasing.In addition, this vehicle operation history management device can prevent the work area (primary data recording area) required for the process of moving location information from becoming too large.

Next, the first index change unit may be configured to record, in the nth index frame, the frame number that was recorded in the ((n×2)-1)th index frame when the first recording processing unit completed recording of the position information, for each of the first index frame to the (M/2)th index frame. The first index change unit may further be configured to record, in the kth index frame, the frame number that was recorded in the ((k×2)-M)th index frame when the first recording processing unit completed recording of the position information, for each of the ((M/2)+1)th index frame to the Mth index frame. The n is an integer from 1 to M/2, and the k is an integer from (M/2+1) to M.

The vehicle operation history management device described above may include a second index changing unit and a third record processing unit.
The second index change unit may be configured to change the reference order information of the index area for a third section and a fourth section following the second section. The second index change unit may record the frame numbers corresponding to the position information that retains a record of the recorded position information even after the reference order information is changed, in each of the first index frame to the (M/2)th index frame in order. The second index change unit may be configured to record the frame numbers corresponding to the position information that does not retain a record of the recorded position information after the reference order information is changed, in each of the ((M/2)+1)th index frame to the Mth index frame in order.

The third recording processing unit may be configured to record the position information in the information frame based on the reference order information recorded by the second index change unit for each third period in the third section and the fourth section. The third period is twice the second period. The third recording processing unit may be configured to record the position information in the information frame corresponding to the frame number according to the order of the frame numbers recorded from the ((M/2)+1) index frame to the M index frame.

The second index change unit may record, in the nth index frame, the frame number that was recorded in the ((n×2)-1)th index frame when the second recording processing unit completed recording of the position information for each of the first index frame to the (M/2)th index frame. The second index change unit may further be configured to record, in the kth index frame, the frame number that was recorded in the ((k×2)-M)th index frame when the second recording processing unit completed recording of the position information for each of the ((M/2)+1)th index frame to the Mth index frame. The n is an integer from 1 to M/2, and the k is an integer from (M/2+1) to M.

The amount of data that can be recorded in the information frame may be greater than the amount of data that can be recorded in the index frame.

1 is a configuration diagram illustrating a schematic configuration of a drive recorder according to a first embodiment. 13 is a flowchart showing the contents of a history information management process. FIG. 2 is an explanatory diagram showing the concept of a recording area for vehicle position history information in a recording unit. FIG. 11 is an explanatory diagram showing an update state of an index area. FIG. 11 is an explanatory diagram showing an updated state of a position information area. FIG. 11 is a diagram illustrating a configuration of a drive recorder according to another embodiment.

Hereinafter, embodiments to which the present disclosure is applied will be described with reference to the drawings.
It goes without saying that the present disclosure is in no way limited to the following embodiments, and various forms can be adopted as long as they fall within the technical scope of the present disclosure.

[1. First embodiment]
[1-1. overall structure]
A vehicle drive recorder 1 (hereinafter, simply referred to as the drive recorder 1) according to the first embodiment is configured to be mounted on a vehicle.

The drive recorder 1 is configured to record video of the vehicle's surroundings. The drive recorder 1 is configured to use GPS (Global Positioning System) data (hereinafter also referred to as location information) to store GPS log data (hereinafter also referred to as vehicle location history information). The vehicle location history information is location information that indicates the vehicle location, and includes multiple pieces of location information at different times. In other words, the vehicle location history information corresponds to information that indicates the vehicle's driving route.

As shown in FIG. 1 , the drive recorder 1 includes a main body 3 , a camera 5 , a GPS module 7 , and a communication module 9 .
The main body 3 is a main part of the drive recorder 1. The main body 3 is configured to execute various processes such as a location history information recording process and a video recording process.

The camera 5 is disposed on the vehicle so as to capture images of the surroundings of the vehicle. The camera 5 is configured to transmit image data relating to the captured image to the main body unit 3. The image capturing direction of the camera 5 is not limited to one direction, and the camera 5 may be configured to capture images in multiple directions.

The GPS module 7 is configured to transmit position information received from GPS satellites to the main body 3. When the drive recorder 1 is mounted on a vehicle, the position information represents the position of the vehicle. The history data of the position information corresponds to vehicle position history information.

The communication module 9 is configured to transmit and receive various information via a wireless communication network based on a predetermined communication protocol. The communication module 9 executes, for example, a communication process for transmitting vehicle position history information from the main body 3 to an external device (e.g., an external server, a management device, a communication terminal device, etc.). The communication module 9 may execute a communication process for transmitting information or commands from an external device to the main body 3. Examples of the wireless communication network include a communication network using mobile phone communication, LTE communication, Bluetooth (registered trademark) communication, wireless LAN (local area network) communication, etc. The communication module 9 transmits and receives information between the drive recorder 1 and an external device installed at a location away from the drive recorder 1.

The main body 3 includes a control unit 11, a recording unit 13, a location information acquisition unit 15, a communication unit 17, a recording medium attachment unit 19, an operation log generation unit 21, a write frame determination unit 23, and an operation log restoration information generation unit 25.

The control unit 11 is configured to control each unit provided in the main body unit 3. The control unit 11 includes a CPU, ROM, RAM, and NVRAM, which are not shown. The CPU is configured to execute processes according to a computer program stored in the ROM. The RAM is used as a working area when the CPU executes processes. The NVRAM is an electrically rewritable non-volatile memory, and stores various data referenced when the CPU executes processes. The processes executed by the control unit 11 are realized by the CPU executing processes according to the computer program stored in the ROM.

The control unit 11 is configured to, for example, record the video data received from the camera 5 on a recording medium (not shown) mounted on the recording medium mounting unit 19. The control unit 11 executes a process of recording location information (hereinafter also referred to as GPS data) on the recording unit 13.

The recording unit 13 includes an internal RAM (not shown) for recording data. The recording unit 13 includes a recording area for recording various types of information. The various types of information include video data, vehicle position history information, and the like. The recording area for the vehicle position history information includes a position information area and an index area. The position information area and index area will be described later.

The location information acquisition unit 15 is configured to acquire location information from the GPS module 7 in accordance with a control command from the control unit 11 .
The communication unit 17 is configured to transmit and receive various information to and from the communication module 9 in accordance with a control command from the control unit 11. The communication unit 17 transmits and receives various information via the communication module 9 and a wireless communication network based on a predetermined communication protocol.

The recording medium mounting unit 19 has a slot for removably mounting a recording medium (not shown). The recording medium may be a memory card or the like. The recording medium mounting unit 19 is configured to write data to the recording medium based on a control command from the control unit 11. Furthermore, the recording medium mounting unit 19 is configured to read data from the recording medium based on a control command from the control unit 11. The recording medium may be used to record video data. The recording medium may be used to record vehicle position history information.

The operation log generating unit 21 is configured to generate vehicle position history information using the position information recorded in the recording unit 13 based on a control command from the control unit 11. In detail, the operation log generating unit 21 generates vehicle position history information using multiple pieces of position information recorded in the position information area and the reference order information recorded in the index area. When multiple pieces of position information are recorded randomly in the recording unit 13, the operation log generating unit 21 generates vehicle position history information by rearranging the multiple pieces of position information in chronological order based on the reference order information. The operation log generating unit 21 can generate vehicle position history information in a data format that can be used by external devices, etc.

The write frame determination unit 23 is configured to determine, based on a control command from the control unit 11, an information frame into which position information is to be written, from among a plurality of information frames in the position information area of the recording unit 13. The write frame determination unit 23 holds information relating to the formulas (4) and (5) described below.

The operation log restoration information generation unit 25 is configured to copy and record the information recorded in the index area and position information area of the recording unit 13 as is, based on a control command from the control unit 11. In other words, the operation log restoration information generation unit 25 can back up the information recorded in the recording unit 13 as is. The operation log restoration information generation unit 25 uses the backed up reference order information and multiple pieces of position information to rearrange the multiple pieces of position information in chronological order, thereby restoring vehicle position history information in a data format that can be used by external devices, etc. Because the operation log restoration information generation unit 25 copies and records the information in the recording unit 13 as is, the process of rearranging the multiple pieces of position information can be omitted, and the information in the recording unit 13 can be backed up in a short time.

The drive recorder 1 may include a display unit and an input unit, not shown. The display unit may be configured using a liquid crystal display or the like. The display unit may be controlled by the control unit 11 to display images captured by the camera 5. Alternatively, the display unit may display various operation screens.

The input unit may receive an operation from a user and transmit a corresponding operation signal to the control unit 11. The input unit may include, for example, mechanical keys that can be pressed by the user. The input unit may include a touch panel disposed adjacent to the display unit.

[1-2. History information management]
Next, the history information management process executed by the control unit 11 will be described with reference to FIG.
The history information management process is a process for managing the vehicle position history information recorded in the recording unit 13. Specifically, when the free space for recording the vehicle position history information in the recording area of the recording unit 13 becomes empty or falls below a predetermined amount, the history information management process is a process for deleting part of the position information in the recorded recording area to secure free space and record new position information.

When the control unit 11 starts the history information management process, it first initializes the index variable n and the stage variable x in S110 (S stands for step). Both the index variable n and the stage variable x are internal variables used for internal processing in the control unit 11. The index variable n is an internal variable that represents the index number of the index area. The stage variable x is an internal variable that represents the change stage regarding the recording density of the vehicle position history information (in other words, the change stage regarding the acquisition period of the position information). Immediately after the start of the history information management process, the stage variable x = 1. If a negative judgment is made in S170 (described later) and the recording density is changed, the stage variable x is incremented by 1 in S190 (described later) to become x = 2. Thereafter, as the recording density is further changed, the stage variable x is incremented by 1.

In S110, the control unit 11 sets initial values for the index variable n and the stage variable x. In this embodiment, the initial values of the index variable n and the stage variable x are both 1 (n=1, x=1).

The location information acquisition time TCx at the xth stage (x=1) is set based on formula (1).

TCa is the basic acquisition time. The basic acquisition time TCa corresponds to the maximum time of the vehicle position history information recorded in the recording unit 13 in the first stage (x=1). The position information acquisition time TCx corresponds to the maximum time of the vehicle position history information recorded in the recording unit 13 in the xth stage.

Now, with reference to FIG. 3, we will explain the recording area of the recording unit 13, which is the recording area for the vehicle position history information. As described above, the recording area includes a position information area and an index area.

FIG. 3 shows the position information area and index area in each stage from the first stage (x=1) to the third stage (x=3).
The location information area includes a number of information frames configured to record vehicle location history information. The number of information frames includes M information frames arranged consecutively from a 0th information frame to an (M-1)th information frame. M represents the number of information frames, is an integer equal to or greater than 2, and is a value corresponding to a power of 2. For example, when M is the mth power of 2, M can be expressed by the following formula (2).

3 shows a case where the location information area includes 16 information frames (M=16=2 ⁴ , m=4) from the 0th information frame F0 to the 15th information frame F15. The information frames are configured to record location information included in the vehicle location history information. In the first stage, location information D1 to D16 is recorded in each of the 0th information frame F0 to the 15th information frame F15.

The index area includes a plurality of index frames configured to record reference order information. The reference order information indicates the reference order of each information frame in the plurality of information frames. The plurality of index frames includes M index frames arranged consecutively from the first index frame to the Mth index frame. In this embodiment, the index area includes 16 (M=16) index frames arranged consecutively from the first index frame I1 to the 16th index frame I16.

Each of the multiple index frames records the frame number of the information frame to be referenced. The multiple index frames are configured to record reference order information in the order of the frame numbers recorded from the first index frame I1 to the sixteenth index frame I16. The reference order information represents the reference order of the multiple information frames.

The data capacity that can be recorded in an information frame is determined according to the data size of the location information. The data capacity that can be recorded in an index frame is determined according to the data size for representing a frame number. In this embodiment, the data size of the location information is larger than the data size for representing a frame number. Therefore, the data capacity that can be recorded in an information frame is larger than the data capacity that can be recorded in an index frame. In this embodiment, the data size of the location information per point is set within the range of 10 to 100 bytes. The data size for representing one frame number is set within the range of 1 to 8 bytes.

In the first stage, each of the multiple index frames is configured to record the frame numbers of the 0th information frame F0 to the 15th information frame F15, from the first index frame I1 to the 16th index frame I16. The reference order information at this time indicates the order in which the 0th information frame F0 to the 15th information frame F15 are referenced in this order.

In the next step S120, the control unit 11 sets an acquisition period Tx and starts measuring the passage of time. The acquisition period Tx corresponds to the period for acquiring location information via the GPS module 7. The acquisition period Tx is set based on formula (3), where x is an integer equal to or greater than 1.

The acquisition period Tx is set to a different value for each x stage. As the update of the x stage progresses (in other words, as x becomes larger), a larger value is set for the location information acquisition time TCx, and a larger value is set for the acquisition period Tx.

In the next step S130, the control unit 11 measures the passage of time and determines whether it is time to obtain location information. If the determination is affirmative, the control unit 11 proceeds to S140, and if the determination is negative, the control unit 11 waits by repeating the same step. The control unit 11 makes a positive determination in S130 each time the acquisition period Tx elapses.

In the next step S140, the control unit 11 acquires position information via the GPS module 7.
In the next step S150, the control unit 11 specifies the frame number N of the information frame into which the position information is to be written. The control unit 11 is configured to transmit a control command to the write frame determination unit 23 and receive the frame number N calculated by the write frame determination unit 23 using the formulas (4) and (5). The control unit 11 may also be configured to read information relating to the formulas (4) and (5) from the write frame determination unit 23 and calculate the frame number N using the formulas (4) and (5).

Equation (4) is a formula for identifying the nth index frame In included in the Pth target section among the M index frames when the entire period of the xth stage is divided into target sections for each basic acquisition time TCa.

P represents the number of the target section that includes the target index variable n among the target sections obtained by dividing the entire period of the xth stage by the basic acquisition time TCa. The number x of target sections in the xth stage (hereinafter also referred to as the number of sections MPx) is calculated using formula (6).

For example, in the first stage (x=1), the number of sections MP1=1. That is, in the first stage, the target section obtained by dividing the entire period of the location information acquisition time TC1 (=1×TCa) for each basic acquisition time TCa is one. Therefore, the target section in the first stage is only the first target section, and the value that P can take is only 1. In the second stage (x=2), the number of sections MP2=2. That is, in the second stage, the target sections obtained by dividing the entire period of the location information acquisition time TC2 (=2×TCa) for each basic acquisition time TCa are two. Therefore, the target sections in the second stage are the first target section and the second target section, and the value that P can take is 1 or 2. In the third stage (x=3), the number of sections MP3=4. That is, in the third stage, the target sections obtained by dividing the entire period of the location information acquisition time TC3 (=4×TCa) for each basic acquisition time TCa are four. Therefore, the target interval in the third stage is the first target interval to the fourth target interval, and the possible values of P are 1, 2, 3, and 4.

Equation (5) is an arithmetic expression for identifying the frame number of an information frame referenced by the n-th index frame In included in the target section P at the x-th stage. In equation (5), when the exponent ^(x-m-1) of 2(x-m-1) is less than 0, 2 ^(x-m-1) is calculated as "0".

The control unit 11 then performs a process of writing the position information into the information frame of frame number N identified in S150 at S160. This causes the position information to be recorded in the information frame of frame number N.

The control unit 11 next determines whether the index variable n is equal to or less than M in S170, and if the determination is affirmative, proceeds to S180, and if the determination is negative, proceeds to S190. In S170, the control unit 11 acquires M pieces of location information and determines whether the location information has been recorded in all of the M information frames. If there is free space in the M information frames (in other words, M pieces of location information have not been acquired), the control unit 11 makes a positive determination in S170. If location information has been recorded in all of the M information frames (in other words, M pieces of location information have been acquired), the control unit 11 makes a negative determination in S170.

If the control unit 11 judges in S170 as positive, it increments the index variable n by 1 (n=n+1) in S180. Thereafter, the control unit 11 executes S130 again. The control unit 11 records M pieces of position information in the recording unit 13 by repeatedly executing the processes from S130 to S180 until the control unit 11 judges in S170 as negative. This causes the vehicle position history information for the entire period of the xth stage to be recorded in the recording unit 13.

If the control unit 11 judges in S170 that the result is negative, in S190, the control unit 11 increments the stage variable x by 1 (x = x + 1). This updates the stage related to the recording density. For example, the stage is updated from the first stage to the second stage, or from the second stage to the third stage.

The control unit 11 changes a part of the reference order information in the index area in the next step S200. The control unit 11 changes the frame number in each of the first index frame to the (M/2)th index frame. In detail, the control unit 11 records the frame number that was recorded in the ((n×2)-1)th index frame at the time of completion of the first recording step in the nth index frame in each of the first index frame to the (M/2)th index frame.

In this embodiment, the control unit 11 changes the frame number in each of the first index frame I1 to the eighth index frame I8 in S200. The frame number to be recorded in each index frame may be determined using the above-mentioned formula (5).

The control unit 11 then sets the index variable n using formula (7) in S210. As a result, in the subsequent processing, recording of position information is performed starting from the ((M/2)+1)th index frame, rather than the first index frame.

Thereafter, the control unit 11 executes S120 again, whereby the control unit 11 moves to the next step and executes recording of the position information.
After the second stage (x≧2), the control unit 11 repeatedly executes the processes from S130 to S180 to first record position information in the information frame of frame number N referenced by the ((M/2)+1)th index frame. Next, the control unit 11 records position information in the information frame based on the frame numbers recorded in each of the ((M/2)+1)th index frame to the Mth index frame.

The update state of the index frame when moving from the first stage to the second stage to the third stage will now be explained with reference to Figure 4. In Figure 4, the top row shows the index area at the completion of the first stage, the middle row shows the index area at the completion of the second stage, and the bottom row shows the index area at the completion of the third stage.

When moving from the first stage to the second stage, the frame numbers (F0 to F15) recorded in each index frame move as shown by the dotted arrows at the top of Figure 4. As a result, when the second stage is completed, the frame numbers N recorded in each index frame are as shown in the middle of Figure 4. In the second stage, the frame numbers N recorded in each index frame are set based on the above-mentioned formulas (4) and (5).

When moving from the second stage to the third stage, the frame numbers (F0 to F15) recorded in each index frame move in the same way, so that the index area at the completion of the third stage will be as shown in the bottom row of Figure 4.

Next, the update state of the location information area when moving from the first stage to the second stage to the third stage will be explained using Figure 5. In Figure 5, the top row shows the location information area at the completion of the first stage, and then the rows below show the update state of the location information area as time passes.

When moving from the completed state of the first stage to the initial state of the second stage, the control unit 11 changes the reference order information of the index area. In other words, the control unit 11 retains the record of half of the position information D1 to D16 recorded in the 16 information frames F0 to F15 even after changing the reference order information, and does not retain the other half of the position information after changing the reference order information. In FIG. 5, the position information to be retained is the position information recorded in the information frame with a frame number of 0 or an even number, and the position information not to be retained is the position information recorded in the information frame with an odd frame number. In FIG. 5, the information frames that retain position information have position information written in them, and the information frames that do not retain position information are shown as blanks. The information frames that do not retain position information have newly acquired position information recorded in the second stage.

When the basic acquisition time TCa has elapsed from the initial state of the second stage and transition has been made to the completion state of the second stage, the control unit 11 records the newly acquired position information D17, D19, D21, D23, D25, D27, D29, and D31 in blank information frames F1, F3, F5, F7, F9, F11, F13, and F15.

Here, the acquisition period Tx of the location information in the first stage (hereinafter also referred to as the first period T1) is T1=CYa/16 by substituting x=1 and M=16 into formula (3). The acquisition period Tx of the location information in the second stage (hereinafter also referred to as the second period T2) is T2=CYa/8 by substituting x=2 and M=16 into formula (3). Thus, in the second stage, the acquisition period (in other words, the acquisition time interval) of the location information is longer (T1<T2) than in the first stage, and the recording density of the location information is reduced. However, in the second stage, the location information can be recorded for a longer period than in the first stage. In other words, in the second stage, the recording density of the location information is reduced compared to the first stage, and vehicle location history information is recorded for a longer period.

When the second stage is completed, as shown in the middle of Figure 3, vehicle position history information can be obtained by referencing the position information in the position information area based on the reference order information recorded in the index area. The entire period of the second stage (position information acquisition time TC2) spans the first interval CY1 and the second interval CY2, and corresponds to twice the period of the first interval CY1, which is the entire period of the first stage (position information acquisition time TC1). Both the first interval CY1 and the second interval CY2 correspond to the same length as the basic acquisition time TCa.

In FIG. 5, when moving from the completed state of the second stage to the initial state of the third stage, the control unit 11 changes the reference order information of the index area. In other words, the control unit 11 retains half of the 16 pieces of position information recorded in the 16 information frames F0 to F15 even after changing the reference order information, and does not retain the other half of the position information after changing the reference order information. In FIG. 5, information frames that retain position information have position information written in them, and information frames that do not retain position information are shown as blanks. Information frames that do not retain position information have newly acquired position information recorded in the third stage.

When the basic acquisition time TCa has elapsed from the initial state of the third stage and the state has transitioned to the intermediate state of the third stage, the control unit 11 records the newly acquired position information D33, D37, D41, and D45 in blank information frames F2, F6, F10, and F14.

Furthermore, when the basic acquisition time TCa has elapsed from the intermediate state of the third stage to the completed state of the third stage, the control unit 11 records the newly acquired position information D49, D53, D57, and D61 in the blank information frames F3, F7, F11, and F15.

Here, the acquisition period Tx of the location information in the second stage (in other words, the second period T2) is T2=CYa/8 as described above. The acquisition period Tx of the location information in the third stage (hereinafter also referred to as the third period T3) is T3=CYa/4 by substituting x=3 and M=16 into formula (3). Thus, in the third stage, the acquisition period (in other words, the acquisition time interval) of the location information is longer (T2<T3) than in the second stage, and the recording density of the location information is reduced. However, in the third stage, location information can be recorded for a longer period than in the second stage. In other words, in the third stage, vehicle location history information is recorded for a longer period while the recording density of the location information is reduced compared to the second stage.

When the third stage is completed, as shown in the bottom row of Figure 3, vehicle position history information can be obtained by referencing the position information in the position information area based on the reference order information recorded in the index area. The entire period of the third stage spans the first interval CY1 to the fourth interval CY4, which is four times the period of the first stage, the first interval CY1. Both the third interval CY3 and the fourth interval CY4 are equal in length to the basic acquisition time TCa.

In this way, the control unit 11 makes a positive determination in S130 and executes S140 to acquire position information for each first period T1 in the first interval CY1 spanning the basic acquisition time TCa. The control unit 11 at this time corresponds to an example of a position information acquisition unit in this disclosure. The processing of the control unit 11 at this time corresponds to an example of a position information acquisition step in this disclosure.

The control unit 11 repeatedly executes S150 while changing the index variable n in S180, thereby recording a predetermined frame number in each of the first index frame to the Mth index frame. In the first stage (x=1), the control unit 11 records the frame numbers corresponding to the 0th information frame to the (M-1)th information frame in that order in each of the first index frame to the Mth index frame. The control unit 11 at this time corresponds to an example of an initial setting unit in the present disclosure. The processing of the control unit 11 at this time corresponds to an example of an initial setting step in the present disclosure.

When the stage variable x is 2 or more (x≧2), the control unit 11 first executes S200 and S210 to set the index variable n to n=(M/2+1), and then repeatedly executes S150 while changing the index variable n in S180. In this way, the control unit 11 records a predetermined frame number in each of the first index frame to the Mth index frame.

That is, in the second stage (x=2), the control unit 11 first records a predetermined frame number in sequence for each of the first index frame to the (M/2)th index frame. The predetermined frame number at this time is the frame number corresponding to the position information recorded in the first stage whose record is also retained in the second stage. Next, the control unit 11 records a predetermined frame number in sequence for each of the ((M/2)+1)th index frame to the Mth index frame. The predetermined frame number at this time is the frame number corresponding to the position information recorded in the first stage whose record is not retained in the second stage.

In detail, in the second stage (x=2), the control unit 11 first records the frame number recorded in the ((n×2)-1)th index frame at the completion of the first stage in the nth index frame for each of the first index frame to the (M/2)th index frame, where n is an integer from 1 to M/2. Furthermore, the control unit 11 records the frame number recorded in the ((k×2)-M)th index frame at the completion of the first stage in the kth index frame for each of the ((M/2)+1)th index frame to the Mth index frame, where k is an integer from (M/2+1) to M.

The control unit 11 at this time corresponds to an example of a first index changing unit in the present disclosure. The processing of the control unit 11 at this time corresponds to an example of a first index changing step in the present disclosure.

In addition, in the third stage (x=3), the control unit 11 first records, in order, the frame numbers corresponding to the position information recorded in the second stage that will be retained in the third stage, in each of the first index frame to the (M/2)th index frame. Next, the control unit 11 records, in order, the frame numbers corresponding to the position information recorded in the second stage that will not be retained in the third stage, in each of the ((M/2)+1)th index frame to the Mth index frame.

In detail, in the third stage (x=3), the control unit 11 first records the frame number recorded in the ((n×2)-1) index frame at the completion of the second stage in the nth index frame for each of the first index frame to the (M/2)th index frame, where n is an integer from 1 to M/2. Furthermore, the control unit 11 records the frame number recorded in the ((k×2)-M) index frame at the completion of the second stage in the kth index frame for each of the ((M/2)+1)th index frame to the Mth index frame, where k is an integer from (M/2+1) to M.

The control unit 11 at this time corresponds to an example of a second index changing unit in the present disclosure. The processing of the control unit 11 at this time corresponds to an example of a second index changing step in the present disclosure.

The control unit 11 repeatedly executes S160 while changing the index variable n in S180, thereby recording the position information acquired in S140 in each of the 0th information frame to the (M-1)th information frame. In the first stage (x=1), the control unit 11 records position information from the 0th information frame to the (M-1)th information frame based on the reference order information for each first period T1 in the first interval CY1. The control unit 11 at this time corresponds to an example of a first recording processing unit in the present disclosure. The processing of the control unit 11 at this time corresponds to an example of a first recording step in the present disclosure.

In the second stage (x=2), the control unit 11 records position information in the second section CY2 for each second period T2 in accordance with the order of the frame numbers recorded from the ((M/2)+1) index frame to the M index frame based on the reference order information. The control unit 11 records the position information for the information frames corresponding to the frame numbers recorded from the ((M/2)+1) index frame to the M index frame. The control unit 11 at this time corresponds to an example of a second recording processing unit in the present disclosure. The processing of the control unit 11 at this time corresponds to an example of a second recording step in the present disclosure.

In the third stage (x=3), the control unit 11 records position information in the third interval CY3 and the fourth interval CY4 in accordance with the order of the frame numbers recorded from the ((M/2)+1) index frame to the M index frame for each third period T3 based on the reference order information. The control unit 11 records the position information for the information frames corresponding to the frame numbers recorded from the ((M/2)+1) index frame to the M index frame. The control unit 11 at this time corresponds to an example of a third recording processing unit in the present disclosure. The processing of the control unit 11 at this time corresponds to an example of a third recording step in the present disclosure.

[1-3. Effects]
As described above, when the recording section of the position information transitions from the first section CY1 to the second section CY2, the vehicle drive recorder 1 of this embodiment updates the reference order information by performing a movement process of the frame numbers recorded in the index area in the recording area of the recording unit 13. By updating the reference order information in this manner, the drive recorder 1 does not need to perform a movement process (in other words, a rearrangement process) of the position information recorded in the information frames in the position information area when the recording section of the position information transitions from the first section CY1 to the second section CY2.

As a result, when the drive recorder 1 changes the recording density of the vehicle position history information (in other words, when changing the period during which the position information is acquired), it is possible to prevent the management of the vehicle position history information in the position information area from becoming complicated.

In addition, when changing the recording density of the vehicle position history information, the drive recorder 1 does not need to move multiple pieces of position information. Therefore, the drive recorder 1 can prevent the time required for the process of moving multiple pieces of position information from becoming long. In addition, since the drive recorder 1 does not need the process of moving position information, it can prevent the working area (primary data recording area) required for the process of moving position information from becoming large.

Next, after recording the position information in the second section CY2, the drive recorder 1 changes the reference order information of the index area for the third section CY3 and the fourth section CY4 that follow the second section CY2. This allows the drive recorder 1 to record not only vehicle position history information over the first section CY1 and the second section CY2, but also vehicle position history information over a longer period of time. This allows the drive recorder 1 to record vehicle positions over a longer period of time even when the size of the recording area is limited.

Furthermore, according to the drive recorder 1, when the recording section of the position information transitions from the second section CY2 to the third section CY3, the frame number recorded in the index area in the recording area of the recording unit 13 is moved, thereby updating the reference order information. As a result, the drive recorder 1 does not need to move (in other words, rearrange) the position information recorded in the information frame when the recording section of the position information transitions from the second section CY2 to the third section CY3. This makes it possible for the drive recorder 1 to prevent the management of vehicle position history information from becoming complicated, and further prevents the time required for the movement process of multiple pieces of position information from becoming long.

The drive recorder 1 is configured such that the amount of data that can be recorded in an information frame is greater than the amount of data that can be recorded in an index frame. In contrast, the drive recorder 1 does not need to rearrange the position information recorded in multiple information frames, so it can quickly expand the free space in the recording area.

[1-4. Correspondence of Words]
Here, the correspondence between the words will be described.
The vehicle drive recorder 1 corresponds to an example of a vehicle operation history management device in the present disclosure, the recording unit 13 corresponds to an example of a recording unit in the present disclosure, and the control unit 11 corresponds to an example of a recording control unit in the present disclosure.

The control unit 11 that executes S140 corresponds to an example of a location information acquisition unit in this disclosure. The control unit 11 that repeatedly executes S150 in the first stage corresponds to an example of an initial setting unit in this disclosure, and the processing of the control unit 11 at this time corresponds to an example of an initial setting step in this disclosure. The control unit 11 that repeatedly executes S160 in the first stage corresponds to an example of a first recording processing unit in this disclosure, and the processing of the control unit 11 at this time corresponds to an example of a first recording step in this disclosure.

In the second stage, the control unit 11 that executes S200 and S210 and then repeatedly executes S150 corresponds to an example of a first index changing unit in the present disclosure, and the processing of the control unit 11 at this time corresponds to an example of a first index changing step in the present disclosure. The control unit 11 that repeatedly executes S160 in the second stage corresponds to an example of a second recording processing unit in the present disclosure, and the processing of the control unit 11 at this time corresponds to an example of a second recording step in the present disclosure.

In the third stage, the control unit 11 that executes S200 and S210 and then repeatedly executes S150 corresponds to an example of a second index changing unit in the present disclosure, and the processing of the control unit 11 at this time corresponds to an example of a second index changing step in the present disclosure. The control unit 11 that repeatedly executes S160 in the third stage corresponds to an example of a third recording processing unit in the present disclosure, and the processing of the control unit 11 at this time corresponds to an example of a third recording step in the present disclosure.

2. Other embodiments
Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and can be embodied in various forms without departing from the gist of the present disclosure.

(a) In the drive recorder 1 of the above embodiment, the main body 3 is configured to include a control unit 11, a recording unit 13, a location information acquisition unit 15, a communication unit 17, a recording medium mounting unit 19, an operation log generation unit 21, a write frame determination unit 23, and an operation log restoration information generation unit 25. However, the vehicle operation history management device disclosed herein is not limited to such a configuration.

For example, as in the second drive recorder 101 shown in FIG. 6, the main body may be configured to be separable into a first main body 103 and a second main body 104. The first main body 103 includes a control unit 11, a location information acquisition unit 15, a recording medium mounting unit 19, and a first USB communication unit 112. The second main body 104 may be configured to include a recording unit 13, a communication unit 17, an operation log generation unit 21, a write frame determination unit 23, an operation log restoration information generation unit 25, a second USB communication unit 114, and a location information receiving unit 115.

The first body unit 103 and the second body unit 104 are connected to each other via a connection cable 106. The connection cable 106 may be realized, for example, by a USB cable 106. The first USB communication unit 112 and the second USB communication unit 114 transmit and receive various information via the connection cable 106, thereby enabling transmission and reception of information between the first body unit 103 and the second body unit 104. The first body unit 103 and the second body unit 104 as a whole correspond to the body unit 3 of the first embodiment.

The second drive recorder 101 achieves the same effects as the vehicle drive recorder 1 by the control unit 11 executing the history information management process.
(b) The number of information frames is not limited to 16, i.e., 0th to 15th information frames, but may be 16, i.e., 1st to 16th information frames, or 16, i.e., 2nd to 17th information frames. In other words, the starting number of the frame numbers of the information frames is not limited to 0. In addition, the number of information frames is not limited to 16 (M=16), but may be any value that is an integer of 2 or more and corresponds to a power of 2.

(c) The recording unit may be a built-in recording unit such as the recording unit 13 described above. The recording unit may also be an external recording unit (such as an SD card). Furthermore, the recording unit may be configured to include both a built-in recording unit and an external recording unit.

(d) The M information frames are not limited to the 0th to (M-1)th information frames, but may be the 1st to Mth information frames, or the 2nd to (M+1)th information frames. Furthermore, the frame numbers need only be assigned individually to each information frame, and the number as the name of the information frame and the frame number do not have to be the same number.

(e) The function of one component in the above embodiments may be distributed among multiple components, or the functions of multiple components may be integrated into one component. At least a part of the configuration of the above embodiments may be replaced with a known configuration having a similar function. A part of the configuration of the above embodiments may be omitted. At least a part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments. Any aspect included in the technical idea identified only by the wording described in the claims is an embodiment of the present disclosure.

1...vehicle drive recorder, 3...main body, 5...camera, 7...GPS module, 9...communication module, 11...control unit, 13...recording unit, 15...location information acquisition unit, 17...communication unit, 19...recording medium mounting unit, 21...operation log generation unit, 23...write frame determination unit, 25...operation log restoration information generation unit, 101...second drive recorder, 103...first main body, 104...second main body, 106...connection cable, 106...USB cable, 112...first USB communication unit, 114...second USB communication unit, 115...location information receiving unit.

Claims (10)

1. An information management method for managing vehicle location history information, comprising:
The vehicle position history information is position information representing a vehicle position and includes a plurality of pieces of the position information at different times, and the vehicle position history information is information recorded in a recording area,
the recording area includes a position information area and an index area,
the location information region comprises a plurality of information frames configured to record the vehicle location history information;
The plurality of information frames comprises M information frames arranged consecutively from a 0th information frame to an (M-1)th information frame,
The 0th information frame to the (M-1)th information frame are each assigned an individual frame number,
The M is an integer equal to or greater than 2 and corresponds to a power of 2;
the index area includes a plurality of index frames configured to record reference order information representing a reference order in the plurality of information frames;
The plurality of index frames include M index frames arranged consecutively from a first index frame to an Mth index frame,
Each of the plurality of index frames is configured to record the frame number of each of the 0th information frame to the (M-1)th information frame from the first index frame to the Mth index frame,
the reference order information is determined based on the order of the frame numbers recorded from the 0th information frame to the (M-1)th information frame,
The information management method is as follows:
a position information acquiring step of acquiring the position information for each predetermined first period in a first section spanning a predetermined basic acquisition time;
an initial setting step of recording the frame numbers corresponding to the 0th information frame to the (M-1)th information frame in the order of the 1st index frame to the Mth index frame;
a first recording step of recording, for each of the first periods in the first section, the position information acquired in the position information acquisition step in each of the 0th information frame to the (M-1)th information frame based on the reference order information recorded in the initial setting step;
a first index changing step of changing the reference order information of the index area for a second section following the first section, the first index changing step recording the frame numbers corresponding to the position information that is to be kept recorded even after the change of the reference order information among the recorded position information in each of the first index frame to the (M/2)th index frame in order, and recording the frame numbers corresponding to the position information that is to be kept recorded but is not to be kept recorded after the change of the reference order information among the recorded position information in each of the ((M/2)+1)th index frame to the Mth index frame in order;
a second recording step of recording the position information in the information frame corresponding to the frame number in accordance with the order of the frame numbers recorded from the ((M/2)+1) index frame to the M index frame based on the reference order information recorded in the first index changing step for each second period that is twice the first period in the second section;
An information management method comprising: 2. The information management method according to claim 1,
The first index changing step includes:
for each of the first index frame to the (M/2) index frame, the frame number recorded in the ((n×2)−1) index frame at the completion of the first recording step is recorded in the n-th index frame, and further, for each of the ((M/2)+1) index frame to the M index frame, the frame number recorded in the ((k×2)−M) index frame at the completion of the first recording step is recorded in the k-th index frame, where n is an integer from 1 to M/2 and k is an integer from (M/2+1) to M.
How information is managed. 3. The information management method according to claim 1, further comprising:
a second index changing step of changing the reference order information of the index area for a third section and a fourth section following the second section, the second index changing step recording the frame numbers corresponding to the position information that is to be kept recorded even after the change of the reference order information among the recorded position information in each of the first index frame to the (M/2) index frame in order, and recording the frame numbers corresponding to the position information that is to be kept recorded but is not to be kept recorded after the change of the reference order information among the recorded position information in each of the ((M/2)+1) index frame to the M index frame in order;
a third recording step of recording the position information in the information frame corresponding to the frame number in accordance with the order of the frame numbers recorded from the ((M/2)+1) index frame to the M index frame, based on the reference order information recorded in the second index changing step, for each third period that is twice the second period in the third section and the fourth section;
An information management method comprising: 4. The information management method according to claim 3,
The second index changing step includes:
for each of the first index frame to the (M/2) index frame, the frame number recorded in the ((n×2)−1) index frame at the completion of the second recording step is recorded in the n-th index frame, and further, for each of the ((M/2)+1) index frame to the M index frame, the frame number recorded in the ((k×2)−M) index frame at the completion of the second recording step is recorded in the k-th index frame, where n is an integer from 1 to M/2 and k is an integer from (M/2+1) to M.
How information is managed. 5. An information management method according to claim 1, further comprising:
A data capacity that can be recorded in the information frame is larger than a data capacity that can be recorded in the index frame.
How information is managed. A vehicle operation history management device,
A recording unit having a recording area for recording vehicle position history information;
a recording control unit configured to record the vehicle location history information in the recording area;
Equipped with
The vehicle position history information is position information representing a vehicle position, and includes a plurality of pieces of the position information at different times;
the recording area includes a position information area and an index area,
the location information region comprises a plurality of information frames configured to record the vehicle location history information;
The plurality of information frames comprises M information frames arranged consecutively from a 0th information frame to an (M-1)th information frame,
The 0th information frame to the (M-1)th information frame are each assigned an individual frame number,
The M is an integer equal to or greater than 2 and corresponds to a power of 2;
the index area includes a plurality of index frames configured to record reference order information representing a reference order in the plurality of information frames;
The plurality of index frames include M index frames arranged consecutively from a first index frame to an Mth index frame,
Each of the plurality of index frames is configured to record the frame number of each of the 0th information frame to the (M-1)th information frame from the first index frame to the Mth index frame,
the reference order information is determined based on the order of the frame numbers recorded from the 0th information frame to the (M-1)th information frame,
The recording control unit
a position information acquisition unit configured to acquire the position information for each predetermined first period in a first section spanning a predetermined basic acquisition time;
an initial setting unit configured to record the frame numbers corresponding to the 0th information frame to the (M-1)th information frame in the 1st index frame to the Mth index frame in that order;
a first recording processing unit configured to record the position information acquired by the position information acquisition unit into each of the 0th information frame to the (M-1)th information frame based on the reference order information recorded by the initial setting unit for each of the first period in the first section;
a first index change unit configured to change the reference order information of the index area for a second section following the first section, the first index change unit configured to record, in order, the frame numbers corresponding to the position information that is recorded and retained even after the reference order information is changed among the recorded position information, in each of the first index frame to the (M/2)th index frame, and to record, in order, the frame numbers corresponding to the position information that is recorded and retained but not retained after the reference order information is changed among the recorded position information, in each of the ((M/2)+1)th index frame to the Mth index frame;
a second recording processing unit configured to record the position information in the information frame corresponding to the frame number in accordance with the order of the frame numbers recorded from the ((M/2)+1) index frame to the M index frame based on the reference order information recorded by the first index changing unit for each second period that is twice the first period in the second section;
A vehicle operation history management device comprising: The vehicle operation history management device according to claim 6,
The first index change unit is
the frame number recorded in the ((n×2)−1)-th index frame at the time when the first recording processing unit completes recording of the position information in each of the first index frame to the (M/2)-th index frame is recorded in the n-th index frame, and further, the frame number recorded in the ((k×2)−M)-th index frame at the time when the first recording processing unit completes recording of the position information in each of the ((M/2)+1)-th index frame to the M-th index frame is recorded in the k-th index frame, wherein n is an integer from 1 to M/2 and k is an integer from (M/2+1) to M.
Vehicle operation history management device. The vehicle operation history management device according to claim 6 or 7,
a second index change unit configured to change the reference order information of the index area for a third section and a fourth section following the second section, the second index change unit configured to record, in order, the frame numbers corresponding to the position information that is to be kept recorded even after the change of the reference order information among the recorded position information, in each of the first index frame to the (M/2) index frame, and to record, in order, the frame numbers corresponding to the position information that is to be kept recorded but is not to be kept recorded after the change of the reference order information among the recorded position information, in each of the ((M/2)+1) index frame to the M index frame;
a third recording processing unit configured to record the position information in the information frame corresponding to the frame number in accordance with the order of the frame numbers recorded from the ((M/2)+1) index frame to the M index frame based on the reference order information recorded by the second index change unit for each third period that is twice the second period in the third section and the fourth section;
A vehicle operation history management device comprising: The vehicle operation history management device according to claim 8,
The second index change unit is
the frame number recorded in the ((n×2)−1)-th index frame at the time when the second recording processing unit completes recording of the position information in each of the first index frame to the (M/2)-th index frame is recorded in the n-th index frame, and further, the frame number recorded in the ((k×2)−M)-th index frame at the time when the second recording processing unit completes recording of the position information in each of the ((M/2)+1)-th index frame to the M-th index frame is recorded in the k-th index frame, wherein n is an integer from 1 to M/2 and k is an integer from (M/2+1) to M.
Vehicle operation history management device. A vehicle operation history management device according to any one of claims 6 to 9,
A data capacity that can be recorded in the information frame is larger than a data capacity that can be recorded in the index frame.
Vehicle operation history management device.

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