Self-position estimation device

Abstract

This own position estimation device has: a position information acquiring unit of a vehicle; a first memory having encoded map information stored therein; a microcomputer that reads the map information, performs a computation based on information obtained from the position information acquiring unit, and outputs driving assistance information; and a second memory that holds the map information and current position information transferred by the microcomputer. The position information acquiring unit, the first memory, and the second memory are connected to the microcomputer via a communication line. The second memory is a non-volatile memory in the vehicle, and stores own position information, encoded surrounding area map information, and decoded surrounding area map information, during operation of the vehicle.

Description

[Technical Field]

[0001] The present invention relates to a self-position estimation device and a driving assistance device, and more particularly to a self-position estimation device for driving assistance that stores map data in a non-volatile memory, and a driving assistance device having a self-position estimation function. [Background technology]

[0002] In recent years, many non-volatile memories characterized by a high number of rewrite cycles have been realized, and some of them have been commercialized. Representative examples include magnetoresistive random access memory (MRAM), ferroelectric random access memory (FeRAM), resistive random access memory (ReRAM), phase change random access memory (PRAM), and carbon nanotube random access memory (NRAM). Due to their high rewrite cycles and non-volatility, they are expected to be used in a variety of applications.

[0003] An example of a device using such nonvolatile memory is described in Patent Document 1. This publication describes a control method for maximizing access performance when using FeRAM or the like as RAM. Patent Document 2 also describes the use of FeRAM as a storage area for writing programs. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-21450 [Patent Document 2] Japanese Patent Application Publication No. 2019-185398 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, there has been an increasing need for self-location estimation functions in automobile driving assistance functions. This is due to the increasing need for driving assistance based on self-location and corresponding map data, including the mandatory support for ISA (Intelligent Speed ​​Assistance) in Europe.

[0006] However, conventional self-location estimation devices have various problems, two of which are particularly significant. The first is the length of time it takes from startup until the self-location information can be used for driving assistance. This is because it takes time to calculate location information from GNSS and because it is necessary to obtain and deploy surrounding map information after the self-location information estimation is complete. As a result, driving assistance based on the self-location information cannot be implemented for a certain period of time after the ignition is turned on.

[0007] The other reason is that large amounts of memory are required to handle the large amounts of map data, and inexpensive microcomputers that do not have a DRAM interface in particular are unable to process map data due to their small RAM capacity, necessitating the use of expensive SoCs. The latter in particular is what makes self-location estimation devices expensive, and is one of the factors that hinder the spread of more advanced driving assistance functions. [Means for solving the problem]

[0008] An example of a self-location estimation device according to the present invention includes: a vehicle location information acquisition unit; a first memory in which encrypted map information is stored; a microcomputer that reads the map information, performs calculations based on the information obtained from the location information acquisition unit, and outputs driving assistance information; a second memory for storing the map information and the current position information transferred by the microcomputer; and the location information acquisition unit, the first memory, and the second memory are connected to the microcomputer via a communication line; The second memory is a non-volatile memory of the vehicle, and stores self-position information, encrypted surrounding area map information, and decrypted surrounding area map information while the vehicle is in operation.

[0009] An example of a driving assistance device according to the present invention includes the above-described self-position estimation device, A self-location estimation function; a function of performing driving assistance using the self-position estimated by the self-position estimation function; have. [Effects of the Invention]

[0010] By using a self-location estimation device according to one example of the present invention, it becomes possible to handle map data in a system that uses an inexpensive microcomputer that does not have a DRAM I / F, thereby making it possible to reduce the price of the self-location estimation device.

[0011] Furthermore, by using a self-location estimation device according to an example of the present invention, it becomes possible to acquire surrounding map information from an external source via the Internet, etc., and perform calculations in a system using an inexpensive microcomputer that does not have a DRAM I / F, thereby enabling the self-location estimation device to be cheaper.

[0012] Furthermore, by using a self-location estimation device according to an example of the present invention, it is possible to avoid the risk of map information being extracted from the self-location estimation device after traveling.

[0013] Furthermore, by using a self-position estimation device according to an example of the present invention, it becomes possible to start driving assistance using self-position estimation shortly after startup, thereby achieving the effect of realizing driving assistance from the start of driving.

[0014] Furthermore, as in one example of a driving assistance device according to the present invention, it is also possible to integrate a device that provides a self-location estimation function and a device that performs driving assistance using information provided by the self-location estimation device. [Brief explanation of the drawings]

[0015] [Figure 1] 1 illustrates a configuration of a self-position estimation device according to a first embodiment. [Figure 2] 2 illustrates a memory configuration and data movement of the self-location estimation device according to the first embodiment. [Figure 3] 4 is a flowchart showing the flow of operations of the self-location estimation device according to the first embodiment. [Figure 4] 10 illustrates a configuration of a self-position estimation device according to a second embodiment. [Figure 5] 10 is a flowchart showing the flow of operations of the self-location estimation device according to the third embodiment. [Figure 6] 10 is a flowchart showing the flow of operations of the self-location estimation device according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, first to fourth embodiments relating to a self-position estimation device and a fifth embodiment relating to a driving assistance device will be described with reference to the drawings.

[0017] [Example 1] 1 shows the configuration of a self-location estimation device according to a first embodiment of the present invention. The self-location estimation device 101 includes a microcomputer 102, a vehicle position information acquisition unit 103, a non-volatile memory 104 (second memory), and a large-capacity memory 105 (first memory). The microcomputer 102 has a processor. The position information acquisition unit 103 includes a group of sensors related to position information acquisition, such as a GNSS information acquisition unit 106 (GNSS: Global Navigation Satellite System) and an IMU sensor 107 (IMU: Inertial Measurement Unit). The GNSS information acquisition unit 106 can acquire information provided by satellite navigation.

[0018] The position information acquisition unit 103 (more specifically, the GNSS information acquisition unit 106 and the IMU sensor 107), the non-volatile memory 104, and the large-capacity memory 105 are each connected to the microcomputer 102 via a communication line.

[0019] Encrypted map information is stored in the large-capacity memory 105. For example, the large-capacity memory 105 stores wide-area encrypted map information 110. The non-volatile memory 104 stores surrounding map information. The surrounding map information includes encrypted surrounding map information 109, which is a copy of necessary parts from the encrypted map information 110, and decrypted surrounding map information 108, which is created by decrypting the encrypted surrounding map information 109.

[0020] The nonvolatile memory 104 can be MRAM, FeRAM, ReRAM, PRAM, or NRAM. These memories are suitable because they can be rewritten many times. The large-capacity memory 105 is a nonvolatile memory such as NAND Flash, which is characterized by low cost and large capacity, but is not limited to these memories as long as it has these characteristics.

[0021] Furthermore, the GNSS information acquisition unit 106 and the IMU sensor 107 are described as examples of the location information acquisition unit 103, but these are representative examples of sensors that can be used to acquire location information, and the type of sensor is not limited to these. For example, a sensor that uses a camera may also be used.

[0022] Furthermore, with regard to the encrypted map information 110 and the encrypted surrounding map information 109, the term "encryption" does not limit the encryption method. It may also include obfuscated information rather than so-called encryption. For example, even if the information does not fall within the specific definition of the term "encryption," it may be difficult to read compared to the map information before processing. As a specific example, it includes information that can be read by performing a predetermined calculation without knowing the decryption key.

[0023] 2 shows the memory configuration and data movement of the self-location estimation device 101 according to this embodiment. In particular, FIG. 2 focuses on the movement of data in the self-location estimation device 101.

[0024] First, the self-position estimation device 101 of this embodiment copies encrypted map information of a predetermined range around the self-position from encrypted map information 110 stored in the large-capacity memory 105 based on self-position estimation information (for example, information indicating the estimated self-position of the vehicle) to the non-volatile memory 104 as encrypted surrounding map information 109. At this time, since the data is transferred sequentially, it does not matter if the RAM size of the microcomputer 102 itself is smaller than the data size of the encrypted surrounding map information 109.

[0025] Next, the microcomputer 102 sequentially reads the data contained in the encrypted surrounding map information 109 and writes it to the non-volatile memory 104 as decrypted surrounding map information 108. At this time, the data is also sequentially transferred and processed, so it does not matter if the RAM size of the microcomputer 102 itself is smaller than the data size of the encrypted surrounding map information 109 and the decrypted surrounding map information 108.

[0026] The non-volatile memory 104 stores self-position estimation information 205 (self-position information) that indicates the estimated self-position of the vehicle, and the microcomputer 102 can read and write the self-position estimation information 205. The self-position estimation information 205 can be obtained from the position information acquisition unit 103, for example.

[0027] In this way, the nonvolatile memory 104 holds the map information (for example, the encrypted surrounding map information 109 and the decrypted surrounding map information 108) transferred by the microcomputer 102 and the current position information (for example, the self-position estimation information 205).

[0028] FIG. 3 is a flowchart showing the operation of the self-location estimation device 101 according to this embodiment, particularly showing the behavior during operation (normal operation). While traveling, the self-location estimation device 101 periodically updates the self-location estimation information 205 based on information acquired from the location information acquisition unit 103 (S100). Then, based on the self-location estimation information 205, it determines whether it is necessary to read the next surrounding map information (S110). For example, it determines whether all map information within a predetermined range based on the self-location has been read, and if there is any portion that has not been read, it determines that it is necessary to read the next surrounding map information. If it is necessary to read the next surrounding map information, it deletes the unused surrounding map information from the non-volatile memory (S120). At this time, it deletes the corresponding portion from both the encrypted surrounding map information 109 and the decrypted surrounding map information 108.

[0029] After the deletion frees up space in the non-volatile memory 104, the encrypted surrounding map information 109 is read based on the area where the surrounding map is needed and copied to the non-volatile memory 104 (S130). After that, the microcomputer 102 decrypts the encrypted surrounding map information 109 newly expanded in the non-volatile memory 104 while reading it, and writes the decrypted surrounding map information 108 to the non-volatile memory (S140).

[0030] In this way, the non-volatile memory 104 stores self-position information (e.g., self-position estimation information 205), encrypted surrounding map information (e.g., encrypted surrounding map information 109), and decrypted surrounding map information (e.g., decrypted surrounding map information 108) while the vehicle is operating.

[0031] After the decoded surrounding map information 108 is decoded, the microcomputer 102 provides the driving assistance device with information necessary for driving assistance based on the self-position estimation information 205 and the information included in the decoded surrounding map information 108 (S150). In this way, the microcomputer 102 reads the map information, performs calculations based on the information obtained from the position information acquisition unit 103, and outputs driving assistance information. The driving assistance information includes, for example, information about speed limits, information about sharp curves, information about road gradients, etc.

[0032] If it is determined in S110 that the next reading of the surrounding map is not necessary, the information necessary for driving assistance is provided to the driving assistance device based on the self-position estimation information 205 and the decoded surrounding map information 108 currently stored in the non-volatile memory 104 (S150).

[0033] As described above, according to the self-location estimation device 101 of this embodiment, even when an inexpensive microcomputer 102 that does not have a DRAM I / F and has a relatively small RAM size is used, it is possible to handle practical map data, thereby making it possible to reduce the price of the self-location estimation device 101.

[0034] [Example 2] Second Embodiment A configuration of a self-location estimation device according to a second embodiment of the present invention is shown in Fig. 4. Hereinafter, explanation of parts common to the first embodiment may be omitted.

[0035] The self-position estimation device 401 includes therein a microcomputer 102, a vehicle position information acquisition unit 103, a non-volatile memory 104 (memory), and a communication IC 405 (network interface).

[0036] The position information acquisition unit 103 (more specifically, the GNSS information acquisition unit 106 and the IMU sensor 107), the communication IC 405, and the non-volatile memory 104 are connected to the microcomputer 102 via a communication line.

[0037] The communication IC 405 is connected via a network to a map server 411 in a data center 410. In response to a request from the communication IC 405 for a specific area, the map server 411 acquires map information for the relevant area from the wide-area encrypted map information 412 and transmits it to the communication IC. The communication IC 405 receives this map information and transfers it to the microcomputer 102.

[0038] Surrounding area map information is stored in the non-volatile memory 104. The surrounding area map information includes received encrypted surrounding area map information 109 and decrypted surrounding area map information 108 created by decrypting the encrypted information.

[0039] In this way, the nonvolatile memory 104 stores encrypted map information (for example, encrypted surrounding map information 109) and current position information (for example, self-position estimation information) that the microcomputer 102 has acquired and transferred via the network.

[0040] The nonvolatile memory 104 is not limited to the described memory as long as it has the same characteristics as the nonvolatile memory 104 according to the first embodiment. The communication IC 405 is connectable to an external network such as Ethernet (registered trademark) and is an IC compatible with a communication method capable of handling large amounts of data such as map data, but the communication method is not limited thereto.

[0041] Similarly to the position information acquisition unit 103 according to the first embodiment, the type of sensor used in the position information acquisition unit 103 is not limited.

[0042] Furthermore, the encryption method for the encrypted map information 412 and the encrypted surrounding map information 109 is not limited, and the information may be obfuscated rather than so-called encrypted.

[0043] The operation of the self-location estimation device 401 according to the second embodiment is based on the operation of the self-location estimation device 101 according to the first embodiment, and differs only in whether the encrypted map is stored inside or outside the self-location estimation device. Therefore, the map server 411 corresponds to the mass memory 105 in Fig. 1, but the other data flows are the same, and the operation in Fig. 3 is the same as that of the self-location estimation device (1) according to the first embodiment.

[0044] In particular, the microcomputer 102 performs calculations and outputs driving assistance information based on information obtained from the position information acquisition unit 103. Furthermore, the non-volatile memory 104 stores self-position information (e.g., self-position estimation information 205), encrypted surrounding map information (e.g., encrypted surrounding map information 109), and decrypted surrounding map information (e.g., decrypted surrounding map information 108) while the vehicle is in operation.

[0045] As described above, according to the self-location estimation device 401 of this embodiment, even if an inexpensive microcomputer 102 without a DRAM I / F is used, it is possible to acquire surrounding map information from the outside via the Internet, etc., and perform calculations. This makes it possible to reduce the price of the self-location estimation device.

[0046] [Example 3] The self-location estimation device according to Example 3 is obtained by adding a termination operation to the self-location estimation device according to Example 1 or 2 from the viewpoint of security. Hereinafter, the description of the parts common to Example 1 or 2 may be omitted.

[0047] Fig. 5 is a flowchart showing the flow of operations of the self-location estimation device according to the third embodiment. Fig. 5 shows processing relating to the end of the operation of the self-location estimation device.

[0048] When the self-location estimation device receives an operation stop request (which may also be called a termination notification) due to, for example, turning off the ignition of the vehicle (S200), the self-location estimation device erases the decoded surrounding area map information 108 stored in the non-volatile memory 104 (S210). Thereafter, the self-location estimation device checks whether the erasure of the decoded surrounding area map information 108 has been completed (S220), and if not completed (S220: NO), executes or continues the erasure process of the decoded surrounding area map information 108 that has not been erased (S210 described above). In this way, the microcomputer 102 discards the decoded surrounding area map information in response to the operation stop request. When the erasure of the decoded surrounding area map information 108 is confirmed (S220: YES), the microcomputer 102 stops operation (S230).

[0049] This has the effect of preventing the decoded surrounding area map information 108 from being read from an external device after the operation has stopped. In other words, it is possible to avoid the risk of map information being extracted from the self-position estimation device after it has traveled.

[0050] Note that the microcomputer 102 does not erase the self-location estimation information 205 and the encrypted surrounding map information 109 even if they are stored in the non-volatile memory 104. That is, the microcomputer 102 saves the self-location estimation information 205 and the encrypted surrounding map information 109 when the microcomputer 102 stops operating.

[0051] [Example 4] The self-location estimation device according to Example 4 is a device that uses the encrypted surrounding map information and self-location estimation information stored in the non-volatile memory at the time of startup in addition to the self-location estimation device according to Example 3, thereby enabling the start timing of driving assistance to be executed earlier. Hereinafter, explanations of parts common to Example 3 may be omitted.

[0052] The flow of operations of the self-location estimation device according to the fourth embodiment is shown in Fig. 6. Fig. 6 shows operations related to the start-up of the self-location estimation device.

[0053] When the self-location estimation device is started by turning on the ignition of the vehicle or the like (S300), the self-location estimation device checks whether the self-location estimation information 205 and the encrypted surrounding area map information 109 are stored in the non-volatile memory 104 (S310). In this way, in response to the start of the vehicle, the microcomputer 102 refers to the self-location estimation information 205 and the encrypted surrounding area map information 109 stored in the non-volatile memory 104.

[0054] If the self-location estimation information 205 and the encrypted surrounding map information 109 are stored (S310: YES), the microcomputer 102 decrypts the encrypted surrounding map information 109 (S320). In this way, if the self-location estimation information 205 and the encrypted surrounding map information 109 are stored in the non-volatile memory 104, the microcomputer 102 decrypts the encrypted surrounding map information 109 and stores it in the non-volatile memory 104.

[0055] After the decoded surrounding map information 108 has been output to the non-volatile memory, the microcomputer 102 reads out the self-location estimation information 205 and the decoded surrounding map information 108, and starts calculating information necessary for driving assistance based on these (S321), and starts driving assistance (S322). In this way, the microcomputer 102 outputs driving assistance information using the self-location estimation information 205 and the decoded surrounding map information 108.

[0056] Since the processing up to this point does not require GNSS, it is possible to obtain the effect of being able to start driving assistance at an earlier timing than a configuration in which the self-position is estimated from information such as GNSS and the encrypted surrounding map information is read only after the self-position estimation is completed. In other words, it is possible to start driving assistance using self-position estimation soon after startup, and it is possible to obtain the effect of realizing driving assistance from the start of driving.

[0057] In steps S320 to S322, if a sensor (the IMU sensor 107 or another sensor) is available, it may be used. When the GNSS becomes available, starting to use information from the GNSS at that point enables more accurate self-location estimation.

[0058] If the encrypted surrounding map information 109 is not stored in the non-volatile memory 104 (S310: NO), such as at the time of initial startup, the device acquires location information in the same manner as a conventional self-location estimation device (S330), and repeatedly checks whether acquisition of location information has been completed (S340). Once acquisition of location information has been completed, the device sequentially copies the necessary encrypted surrounding map information from the encrypted surrounding map information 109 to the non-volatile memory 104 (S350), decrypts the encrypted surrounding map information 109 (S351), reads out the self-location estimation information 205 and the decrypted surrounding map information 108 (S352), and starts calculating the information necessary for driving assistance based on these, thereby starting driving assistance (S353).

[0059] In this case, the effect of shortening the time from startup to the start of driving assistance is not obtained, but since the self-position estimation information 205 and encrypted surrounding map information 109 remain in the non-volatile memory when normal operation ends (see Example 3), the effect is not obtained in only a few cases.

[0060] [Example 5] The driving assistance device according to this embodiment is configured such that a device that performs self-location estimation using any of the self-location estimation devices according to embodiments 1 to 4 and outputs driving assistance information simultaneously performs driving assistance using the information. That is, the self-location estimation device 101 or 401 also functions as a driving assistance device. Hereinafter, a description of parts common to any of embodiments 1 to 4 may be omitted.

[0061] For example, the microcomputer 102 has a multi-core configuration, i.e., includes a plurality of processors, one or more of which implements the self-location estimation device according to any one of the first to fourth embodiments, and one or more of which implements the driving assistance device.

[0062] As described above, the driving assistance device according to this embodiment includes a self-location estimation device and has a self-location estimation function, and has a function of performing driving assistance using the self-location estimated by this self-location estimation function.

[0063] The specific content of the driving assistance is not particularly limited, but can be designed appropriately by a person skilled in the art based on known technology, and can provide assistance with operations such as accelerating, braking, steering, etc.

[0064] As an effect of the self-location estimation device according to Examples 1 to 4, since an inexpensive microcomputer can function as the self-location estimation device, it is possible to integrate it with a driving assistance device realized by an inexpensive microcomputer, and it is possible to obtain an effect that even a low-cost driving assistance device can realize high-performance driving assistance based on self-location estimation. In other words, it is possible to integrate a device that provides the self-location estimation function and a device that performs driving assistance using information provided by the self-location estimation device. [Explanation of symbols]

[0065] 101: Self-position estimation device (driving assistance device) 102: Microcomputer 103: Location information acquisition unit 104: Non-volatile memory (second memory, memory) 105: Large capacity memory (first memory) 106:GNSS information acquisition section 107: IMU sensor 108: Decoded surrounding area map information (decoded surrounding area map information) 109: Encrypted surrounding map information (encrypted surrounding map information) 110: Encrypted map information 205: Self-location estimation information (self-location information) 401: Self-position estimation device (driving assistance device) 405: Communication IC (Network Interface)

Claims

1. a vehicle location information acquisition unit; a first memory in which encrypted map information is stored; a microcomputer that reads the map information, performs calculations based on the information obtained from the location information acquisition unit, and outputs driving assistance information; a second memory for storing the map information and the current position information transferred by the microcomputer; and the location information acquisition unit, the first memory, and the second memory are connected to the microcomputer via a communication line; the second memory is a non-volatile memory of the vehicle, and stores self-location information, encrypted surrounding area map information, and decrypted surrounding area map information while the vehicle is in operation; Self-location estimation device.

2. a vehicle location information acquisition unit; a microcomputer that performs calculations based on the information obtained from the position information acquisition unit and outputs driving assistance information; a memory for storing encrypted map information and current location information acquired and transferred by the microcomputer through a network interface; and the location information acquisition unit, the network interface, and the memory are connected to the microcomputer via a communication line; the memory is a non-volatile memory of the vehicle, and stores self-location information, encrypted surrounding area map information, and decrypted surrounding area map information while the vehicle is in operation; Self-location estimation device.

3. 3. The self-location estimation device according to claim 1, The microcomputer discards the decoded surrounding area map information in response to the operation stop request, The microcomputer stores the self-location information and the encrypted surrounding map information when the microcomputer stops operating. Self-location estimation device.

4. The self-location estimation device according to claim 1 , In response to the start of the vehicle, the microcomputer refers to the self-location information and the encrypted surrounding area map information stored in the second memory, When the self-location information and the encrypted surrounding area map information are stored in the second memory, the microcomputer decrypts the encrypted surrounding area map information and stores it in the second memory; The microcomputer outputs driving assistance information using the self-position information and the decoded surrounding map information. Self-location estimation device.

5. The self-location estimation device according to claim 1 , the second memory is MRAM, FeRAM, ReRAM, PRAM or NRAM; Self-location estimation device.

6. a self-location estimation device according to claim 1 or 2; A self-location estimation function; a function of performing driving assistance using the self-position estimated by the self-position estimation function; A driving assistance device with

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