Self-position acquisition device

Abstract

The purpose of the present invention is to provide a self-position acquisition device capable of stably performing high-precision positioning while suppressing costs by performing positioning as much as possible by using an individual positioning method by minimizing the use of a network assistance method. In the present invention, a first positioning method (e.g., CLAS or HAS) and a second positioning method (network assistance method) are switched on the basis of a hindering period in which precision is reduced in the first positioning method and a valid period in which enhancement information is valid. The first positioning mode performs positioning based on receiving information of positioning electric waves received from a positioning satellite and enhancement information for enhancing the receiving information; the second positioning mode performs positioning based on the received information and positioning auxiliary information received from the positioning server via the network.

Description

Technical Field

[0001] The invention relates to a device for acquiring a self position. Background Art

[0002] Conventionally, technologies for measuring the current position of a mobile object are known. For example, there is a known independent positioning method, in which a vehicle independently locates its own vehicle based on reception information carried in radio waves received from positioning satellites. Furthermore, there is also known a network-assisted method, in which the vehicle's own positioning is performed based on reception information and positioning assistance information received from a positioning server via a network. Furthermore, Patent Document 1 discloses a technology that combines these two positioning methods.

[0003] In the technology of Patent Document 1, when the vehicle is detected in a closed space above, is predicted to move in the near future, or the quality of radio waves is lower than a specified level, the positioning method is switched from the independent positioning method to the network-assisted method. Prior art literature Patent Literature

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2009-115573 Summary of the Invention Problems to be solved by the invention

[0005] However, even in enclosed spaces, such as pedestrian bridges, there are many cases where the distance between the positioning satellite and the vehicle is momentarily blocked. Even in such situations, switching to network-assisted mode every time, as in the technique described in Patent Document 1, may result in excessive network usage fees and other costs.

[0006] The present invention is completed in view of the above-mentioned problems, and its purpose is to provide a self-position acquisition device, which minimizes the use of network assistance and uses independent positioning as much as possible for positioning, thereby being able to stably perform high-precision positioning while suppressing costs. Technical means to solve the problem

[0007] In order to solve the above problems, the self-position acquisition device of the present invention is mounted on the self-vehicle, and switches between the first positioning mode and the second positioning mode. The first positioning mode performs positioning based on the reception information of the positioning radio waves received from the positioning satellite and the enhanced information that enhances the reception information. The second positioning mode performs positioning based on the reception information and the positioning auxiliary information received from the positioning server via the network. The self-position acquisition device switches the first positioning mode to the second positioning mode based on the obstruction period during which the accuracy is reduced in the first positioning mode and the validity period of the enhanced information. Effects of the Invention

[0008] According to the present invention, a self-position acquisition device can be provided that minimizes the use of a network-assisted method and performs positioning by independent positioning as much as possible, thereby enabling stable high-precision positioning at a reduced cost. Other problems, structures, and effects than those described above will become clear from the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a block diagram illustrating the configuration of the self-position acquisition device according to the first embodiment. Figure 2 To illustrate the Figure 1 Flowchart showing an example of the flow of the positioning method switching process performed by the self-position acquisition device shown. Figure 3 This is a diagram illustrating the relationship between each frame of enhanced information and the effective period of the enhanced information according to the first embodiment. Figure 4A This is a diagram showing, in chronological order, the state of the effective period of enhanced information when the reception of enhanced information is blocked in the first embodiment. Figure 4B 1 and 2 are diagrams showing, in chronological order, the states of the effective period of the enhanced information when the reception of the enhanced information is temporarily blocked according to the first embodiment. Figure 5 This is an explanatory diagram regarding selection of positioning satellites when calculating the amount of movement of the own vehicle based on satellite positioning according to the second embodiment. Figure 6 This is a block diagram illustrating the configuration of a self-position acquisition device according to a second embodiment. Figure 7 To indicate Figure 6 1 is a flowchart of an example of a determination process for switching the own vehicle movement amount calculation method by the calculation method switching unit shown. Figure 8 3 is a block diagram showing a self-position acquisition device according to a third embodiment. DETAILED DESCRIPTION

[0010] Hereinafter, embodiments of the present invention will be described using the accompanying drawings. Configurations assigned the same reference numerals in each embodiment have the same functions in each embodiment unless otherwise specified, and description thereof will be omitted.

[0011] [First embodiment] Figure 1This is a block diagram illustrating the configuration of the own position acquisition device 1 of the first embodiment. The own position acquisition device 1 is mounted on the own vehicle and acquires the own vehicle's position relative to a travel path such as a straight road or a curve as the own position and transmits it to other devices in the vehicle.

[0012] The self-position acquisition device 1 is connected to a positioning device 2 and an external recognition device 3 .

[0013] The positioning device 2 is mounted on the vehicle and includes a first receiver 21 that receives positioning radio waves from multiple positioning satellites; a second receiver 22 that receives augmentation information from other positioning satellites than the multiple positioning satellites to enhance the positioning radio wave reception information; a third receiver 23 that receives positioning assistance information from a positioning server via a network to supplement the positioning radio wave reception information; and a positioning engine 24 that performs positioning calculations using either a first positioning method based on the positioning radio wave reception information and the augmentation information, or a second positioning method based on the positioning radio wave reception information and the positioning assistance information. The positioning radio wave reception information includes at least one of the date and time the positioning satellite transmits the positioning radio wave, the positioning satellite's own position information, orbital information of other positioning satellites, and ionospheric information.

[0014] The first and second receivers 21, 22 are GNSS receivers that receive positioning radio waves or augmentation information from positioning satellites such as GPS satellites and Quasi-Zenith Satellites. The third receiver 23 is a communication device for receiving positioning assistance information used in positioning methods generally known as Network RTK-GNSS. The positioning engine 24, comprised of, for example, a microcontroller, performs positioning operations to calculate the device's own position information, such as latitude, longitude, altitude, and time, and outputs it to the device 1. The positioning device 2 also outputs the augmentation information acquired by the second receiver 22 to the device 1.

[0015] The first receiver 21 and the second receiver 22 are not limited to GNSS receivers, but may be simple devices that track signals from positioning satellites based on received positioning radio wave information. In this case, the self-position information is calculated in the self-position acquisition device 1. The first receiver 21 and the second receiver 22 are not limited to separate receivers, but may be integrally formed within the same body to receive both positioning radio waves and augmented information.

[0016] The first positioning method is a separate positioning method that calculates the current position based solely on positioning radio waves from positioning satellites. In the self-position acquisition device 1 of this embodiment, the first positioning method is the preferred positioning method used as long as the reception of positioning radio waves is not blocked, making positioning difficult. In the first positioning method, high-precision positioning is achieved by using positioning enhancement information services such as CLAS (Centimeter Level Augmentation Service) and HAS (High Accuracy Service) using enhanced information transmitted from specific positioning satellites.

[0017] In the first positioning method, the amount of error for each major factor, such as satellite clock error, satellite orbit error, satellite signal bias, and ionospheric delay error, is obtained from the augmentation information. This error amount for each major factor is then used to correct the positioning radio wave reception information received from multiple other positioning satellites, thereby achieving high-precision positioning.

[0018] The first positioning mode requires continuous reception of one frame of augmentation information. For example, in CLAS, receiving one frame of augmentation information from the Quasi-Zenith Satellite guidance system takes 30 seconds. For example, if an obstruction such as a pedestrian bridge, overpass, or tunnel exists between the specific positioning satellite transmitting the augmentation information and the receiving antenna of positioning device 2 during the reception of one frame of augmentation information, preventing the second receiver 22 from receiving the augmentation information, the augmentation information cannot be used, and the error correction for each major factor contained in the frame cannot be performed.

[0019] Furthermore, enhanced information has the following characteristics: even when reception of a single frame is completed without interruption, the error amounts due to various factors change over time. Therefore, after a certain period of time has passed since reception was completed, the enhanced information becomes unusable, and correction of the error amounts due to various factors contained in the frames using the enhanced information becomes unavailable. The time from the completion of enhanced information reception until it becomes unusable varies depending on the type of positioning enhancement information service and the expected positioning accuracy, but is generally set at approximately 60 seconds.

[0020] The second positioning method is a network-assisted method that calculates the current position based on the positioning assistance information received from the positioning server via the communication network and the reception information of the positioning radio waves from the positioning satellite. As a second positioning method, for example, in addition to the positioning radio waves from the positioning satellite, an RTK (Real Time Kinematic) method based on the observation information of the positioning radio waves of the reference station set or set near the own vehicle can also be used for positioning. The RTK method is a method of eliminating positioning errors based on dual phase differences, and there is no need to continue to receive enhanced information such as the above-mentioned positioning enhancement information service. In the second positioning method, it is necessary to continue to obtain the observation information of the reference station via the communication line. Therefore, when a charged network is used in the communication between the positioning server, communication costs are incurred.

[0021] The outside world recognition device 3 is mounted on the own vehicle and recognizes the outside world around the own vehicle. As the outside world recognition device 3, mainly considered are sensors such as stereo cameras or LiDAR that measure the distance or position relationship with the object. In addition, as the outside world recognition device 3, a device that can observe the size and type of the object is preferred. The outside world recognition device 3 obtains information about objects in spaces where the positioning accuracy is reduced due to the inability to receive enhanced information from specific positioning satellites (hereinafter also referred to as object information). The object information includes information about the distance to the object, preferably including information about the distance to the object, the arrival time of the own vehicle at the object, the positional relationship between the own vehicle and the object, the size of the object, and the type of the object. The outside world recognition device 3 sends the object information obtained by measurement to the own position acquisition device 1.

[0022] In this embodiment, obstacles such as pedestrian bridges and overpasses related to the vehicle's path, as well as buildings along the vehicle's path, that block the path between the specific positioning satellite transmitting augmented information and the receiving antennas of each receiver are considered obstructions. In other words, obstacles in the external environment that have the potential to block the airspace above the vehicle are considered obstructions. Furthermore, the distance to the obstruction, the arrival time, the magnitude of the obstruction, the positional relationship between the vehicle and the obstruction, and the type of obstruction are used as obstruction object information (hereinafter referred to as obstruction information). Furthermore, "obstruction" refers to obstruction between the specific positioning satellite and the receiving antennas of each receiver, resulting in a reduction in positioning accuracy due to external environmental factors.

[0023] The self-position acquisition device 1 is composed of, for example, one or more microcontrollers, which include a central processing unit (CPU), a memory such as ROM and RAM, a timer, and an input and output unit. Figure 1As shown, the self-position acquisition device 1 includes a position acquisition unit 101, a blocking period calculation unit 102, an effective period acquisition unit 103, and a positioning mode switching unit 104, and these units are implemented by software processing of a microcontroller.

[0024] The position acquisition unit 101 acquires the vehicle's own position information from the positioning device 2. The position acquisition unit 101 transmits the acquired position information to other devices within the vehicle. For example, the position acquisition unit 101 may acquire the latitude, longitude, altitude, time, etc. obtained by performing positioning calculations on the first receiver 21.

[0025] The position acquisition unit 101 may also acquire the vehicle's own position information from the outside world recognition device 3. For example, the vehicle's own position may be estimated based on information such as signs, billboards, storefronts, and road markings captured using a monocular camera of the outside world recognition device 3, and a map. Alternatively, the vehicle's own position information may be acquired by observing the vehicle using sensors installed on an independent infrastructure separate from the vehicle via wireless communication, optical communication, or the internet.

[0026] The obstruction period calculation unit 102 calculates the obstruction period during which the accuracy of the first positioning method for acquiring the vehicle's position is reduced. The obstruction period calculation unit 102 obtains object information transmitted from the external recognition device 3 to calculate the obstruction period. For example, using a stereo camera, the unit identifies obstacles such as pedestrian bridges or overpasses in the vehicle's path that may block the path between the specific positioning satellite transmitting the augmentation information and the receiving antenna of the positioning device 2, and measures the distance and size of these obstacles.

[0027] The obstruction period calculation unit 102 decodes the received positioning radio waves from the specific positioning satellite that transmits the augmentation information to obtain the elevation and azimuth angles of the specific positioning satellite that transmits the augmentation information. The obstruction period calculation unit 102 uses the distance from the vehicle to the object and the object's size, as included in the acquired object information, the decoded elevation and azimuth angles of the specific positioning satellite, and the vehicle's speed and direction of travel to determine whether the reception of the augmentation information is obstructed. The obstruction period calculation unit 102 transmits the determination result to the positioning mode switching unit 104.

[0028] If it is determined that the reception of enhanced information is obstructed, the obstruction period calculation unit 102 further calculates the obstruction start time based on the object information, primarily the distance to the object, the positional relationship between the own vehicle and the object, the own vehicle's speed, the own vehicle's direction of travel, and the elevation and azimuth angles of specific positioning satellites. Next, based on the obstruction start time and the object information, primarily the size and type of the object, the obstruction end time is calculated. The obstruction start time is the time when the object begins to obstruct the reception of enhanced information. The obstruction end time is the time when the object ceases to obstruct the reception of enhanced information. The period from the obstruction start time to the obstruction end time is called the obstruction period. The obstruction period calculation unit 102 transmits the calculated obstruction period information to the positioning mode switching unit 104. The obstruction period can also be referred to as the obstruction period during which the airspace above the own vehicle is obstructed.

[0029] While the example of a stereo camera has been used as a means of identifying obstacles, LiDAR can also be used. Alternatively, the vehicle's position can be determined using other sensors such as cameras, combined with map information to identify obstacles and calculate the start or end time of the obstruction. Alternatively, the obstruction duration can be obtained by receiving it through external communication.

[0030] The obstruction period calculation unit 102 calculates the position of the vehicle t seconds from now based on, for example, the distance to the object, the positional relationship between the vehicle and the object, the vehicle's speed, and the vehicle's travel direction. Based on the calculated vehicle position and the elevation and azimuth angles of the specific positioning satellite, the unit determines whether the object is blocking the path between the specific positioning satellite and the receiving antenna. If it is determined that the object is blocking the path between the specific positioning satellite and the receiving antenna, the time t seconds from now is designated as the obstruction start time.

[0031] When calculating the obstruction end time, the obstruction period calculation unit 102 may also determine, based on the object type, whether the obstruction is momentary or continuous, lasting for a predetermined period or longer. Specifically, in the case of a short-passable object such as a billboard mounted on a gantry, a pedestrian overpass, or a bicycle overpass, since the object passes under it in a short time, such as approximately one second, it is identified as a momentary obstruction, and (t+1) is used as the obstruction end time. On the other hand, in the case of an object that lasts for a long time, such as tens of seconds or longer, such as a tunnel or the underpass of a multi-story road, it is identified as a continuous obstruction lasting for a predetermined period or longer, and the value t plus a certain value is used as the obstruction end time.

[0032] In addition, when an object that could become the target, such as an obstacle or shield, cannot be observed on the path of the own vehicle, or when the target is far away or the speed of the own vehicle is low and the target is not reached within a specified time, such as within the frame length of the enhanced information, it can also be calculated as an object without obstruction.

[0033] Furthermore, to reduce the processing load of image recognition, the recognition targets can be simplified. For example, only obstacles caused by obstructions above the vehicle can be detected.

[0034] The validity period acquisition unit 103 acquires the validity period of the augmentation information used for positioning. Within the augmentation information received from a specific positioning satellite, the validity period acquisition unit 103 acquires the time at which the augmentation information is received, which serves as the start point of the validity period of the augmentation information. For example, in the case of CLAS augmentation information, the validity period acquisition unit 103 decodes the augmentation information transmitted from the specific positioning satellite in the L6 frequency band. The frame length of the augmentation information is known according to the specifications of each augmentation information.

[0035] In the case of CLAS-based augmentation information, the satellite clock is set to 5 seconds, and information such as ionospheric correction, atmospheric correction, and satellite orbit is transmitted every 30 seconds. The message format, length, and bit rate are also strictly defined. Furthermore, these details are distinguished by the subtype number in the satellite message. Therefore, the validity period acquisition unit 103 can obtain the enhanced information reception completion time based on the decoding results. The enhanced information reception completion time refers to the time when the reception of one frame of enhanced information is completed.

[0036] The information contained in the enhanced information deviates from the actual state over time. If this occurs for an extended period, the information may deviate to such an extent that it becomes unusable. Therefore, the validity period acquisition unit 103 determines the validity period of the enhanced information. The validity period of the enhanced information is the period during which the deviation from the actual state can be tolerated during use. For example, in this embodiment, it is set to 60 seconds from the moment the enhanced information is received.

[0037] The validity period of the augmentation information can also be determined by using the values specified for each piece of information included in the augmentation information. For example, in the case of CLAS, the specifications define a 10-second validity period for the satellite clock and a 60-second validity period for information such as ionospheric correction, atmospheric correction, and satellite orbit. However, because augmentation information may deviate from actual conditions over time, the validity period of the augmentation information can be set to a shorter value, particularly when accuracy is required.

[0038] For example, if the fluctuation in ionospheric delay error increases due to the occurrence of a solar flare, the effective period of the augmentation information can be changed based on the fluctuation in the error information. Specifically, during periods of active solar flares, where ionospheric disturbances increase, the effective period of the augmentation information can be set shorter. Conversely, during periods of quiet solar flares, the effective period of the augmentation information can be set longer.

[0039] The positioning mode switching unit 104 determines whether a period during which the enhanced information received by the positioning device 2 cannot be used has occurred based on the blocking period and the enhanced information validity period. For example, if it is determined that the blocking period is longer than the enhanced information validity period, resulting in a period during which the enhanced information cannot be used, an instruction is output to the positioning device 2 to switch the positioning mode of the positioning device 2 from the first positioning mode to the second positioning mode in advance. On the other hand, if it is determined that even if a blocking period occurs, it is within the enhanced information validity period, resulting in a period during which the enhanced information cannot be used, the positioning mode is not switched, and an instruction is output to the positioning device 2 to maintain the first positioning mode.

[0040] When switching the positioning method from the first positioning method to the second positioning method, the positioning device 2 needs to establish a communication link, select a nearby base station, or send the latitude and longitude of the vehicle used to generate positioning assistance information to the positioning server, and wait for a response from the server. Therefore, the positioning method switching unit 104 outputs an instruction to the positioning device 2 before switching to the second positioning method to initiate preparatory processing for switching to the second positioning method, such as establishing a communication link.

[0041] When the blocking period ends and the enhanced information can be used while the second positioning method is being executed, the positioning method switching unit 104 outputs an instruction to the positioning device 2 to restore the second positioning method to the first positioning method.

[0042] Figure 2 Yes Figure 1 Flowchart showing an example of the flow of the switching process of the positioning method of the self-position acquisition device 1.

[0043] The blocking period calculation unit 102 of the own position acquisition device 1 acquires the enhanced information from the second receiver 22 (step S101 ). The acquired enhanced information is provided to the positioning method switching unit 104 via the valid period acquisition unit 103 .

[0044] The obstruction period calculation unit 102 calculates the obstruction period (step S102). The obstruction period calculation unit 102 determines the presence of an object based on the object information obtained by the external recognition device 3, the elevation angle and azimuth angle of the specific positioning satellite obtained by decoding the enhanced information, and the vehicle's own vehicle speed and direction of travel. If an object is observed, the obstruction period is calculated and information including the start and end times of the obstruction period is provided to the positioning mode switching unit 104. If the object is not observed or the object is not reached within the specified time, the obstruction period calculation unit 102 provides the positioning mode switching unit 104 with information indicating that there is no obstruction period.

[0045] The positioning mode switching unit 104 checks whether an obstruction period exists (step S103). If it is determined that an obstruction period exists ("Yes" in step S103), the unit identifies the enhanced information that was received before the obstruction period and determines the first time tA at which the validity period of the identified enhanced information ends (step S104). The positioning mode switching unit 104 compares the obstruction start time with the enhanced information reception completion time and identifies the enhanced information that is closest to the obstruction start time and received before the obstruction period. For this identified enhanced information, the first time tA is determined as the time at which the validity period of the enhanced information ends.

[0046] After determining the first time tA, the positioning mode switching unit 104 determines the second time tB, which is the start time of the effective period of the enhanced information to be received after the end of the blocking period (step S105). The positioning mode switching unit 104 compares the blocking end time during the blocking period with the enhanced information reception completion time and determines the enhanced information closest to the blocking end time and received after the blocking end time. Then, for this determined enhanced information, the start time of the effective period of the enhanced information is determined as the second time tB.

[0047] Specifically, the second time tB can be determined using the following formula. Let the obstruction end time be trep, the period of one enhanced information frame be tint, and the time when the previous enhanced information reception was completed be told. First, the minimum P is calculated using the following formula. As mentioned above, the obstruction end time and the period of the enhanced information frame are known. [Formula 1] trep<told+tint×P

[0048] Next, the second time tB is calculated using the following formula. [Formula 2] tB=told+tint×P

[0049] When determining the first time tA and the second time tB, the positioning mode switching unit 104 determines whether the second time tB arrives before the first time tA (step S106). If the second time tB does not arrive by the first time tA (No in step S106), that is, if the second time tB arrives after the first time tA, a period during which any augmentation information sequentially received by the positioning device 2 cannot be used has occurred, and an instruction is output to the positioning device 2 to switch the positioning mode of the positioning device 2 from the first positioning mode to the second positioning mode in advance (step S107). On the other hand, if the second time tB arrives before the first time tA (Yes in step S106), continuity between the validity periods of the plurality of augmentation information can be maintained, and an instruction is output to the positioning device 2 to maintain the first positioning mode (step S110).

[0050] The positioning mode switching unit 104 outputs an instruction to the positioning device 2 to switch the positioning mode from the first positioning mode to the second positioning mode in coordination with the first time tA. Preferably, the positioning mode switching unit 104 begins pre-processing for switching to the second positioning mode, such as establishing a communication link, before the first time tA, and outputs the instruction to the positioning device 2, so that once the pre-processing is completed, the positioning device 2 switches to the second positioning mode before the first time tA arrives.

[0051] The positioning mode switching unit 104 outputs an instruction to the positioning device 2 to return the positioning mode from the second positioning mode to the first positioning mode at the second time tB (step S108). After the positioning mode is returned from the second positioning mode to the first positioning mode, the positioning mode switching unit 104 outputs an instruction to the positioning device 2 to execute a process such as disconnecting the communication link used in the second positioning mode (step S109).

[0052] Figure 3 This is a diagram showing the relationship between each frame of enhanced information and the effective period of the enhanced information according to the present embodiment. Figure 3 The times t1 , t2 , t3 , t4 , and t5 shown are divided at regular intervals. Although not shown, the operation of the self-position acquisition device 1 of this embodiment continues without interruption after t5 .

[0053] A specific positioning satellite transmits unique enhancement information in sequence at predetermined intervals. Each enhancement information is transmitted continuously without interruption. Each enhancement information has the same fixed frame length, and the frame reception time required for the positioning device 2 to receive one frame is also the same length. For example, in this embodiment, Figure 3 As shown, the positioning device 2 continuously receives augmentation information A, B, C, D, and E from a specific positioning satellite. Although not specifically shown, the augmentation information is continuously received after E. In the positioning device 2, when the reception of the previous augmentation information is completed, the reception of the next augmentation information is continuously started. Figure 3 In the example shown, if the reception of the enhanced information A is completed at time t1, the reception of the enhanced information B starts at the same time t1.

[0054] The validity period of enhanced information begins when reception of one frame of enhanced information is completed. The validity period of enhanced information is set so that the validity period of one enhanced information partially overlaps with the validity period of the next enhanced information. For example, in this embodiment, the validity period of enhanced information is set to twice the frame reception time required to receive one frame. If positioning device 2 can continuously and normally receive one frame of enhanced information, the validity period is set to the time from the moment reception is completed to the moment the frame reception time required for the two preceding frames has elapsed.

[0055] exist Figure 3 In the example shown, the second half of the effective period A' of enhanced information A overlaps with the first half of the effective period B' of enhanced information B. The effective period A' of enhanced information A runs from time t1 to time t3, while the effective period B' of enhanced information B runs from time t2 to time t4. For the portion where the effective period of an enhanced information overlaps with the effective period of the next enhanced information, the self-position acquisition device 1 utilizes the newer information, the next enhanced information, provided that either enhanced information has been received.

[0056] exist Figure 3 In the example shown, there is no blocking period, and no period during which the augmented information cannot be used. Therefore, the positioning mode switching unit 104 does not output a positioning mode switching instruction, and the first positioning mode is maintained as the positioning mode of the positioning device 2 .

[0057] Figure 4A and Figure 4B This is a diagram showing the state of the effective period of enhancement information when the reception of enhancement information is blocked according to the present embodiment in a chronological order.

[0058] The following uses Figure 4A and Figure 4BThe operations of the positioning method switching unit 104 according to the present embodiment (1) switching to the second positioning method mode and (2) maintaining the first positioning method mode will be described in detail.

[0059] (1) Switch to the second positioning mode exist Figure 4A In the example shown, blocking period t10 begins while enhanced information B is being received, and ends while enhanced information D is being received. Therefore, positioning device 2 cannot use enhanced information B, C, or D. However, it can use enhanced information E starting at time t5, when enhanced information E, which begins receiving after blocking period t10, is received. Consequently, a period during which enhanced information cannot be used occurs from time t3, when the effective period A' of enhanced information A ends, to time t5, when enhanced information E can begin using it.

[0060] exist Figure 4A In the example shown, the positioning mode switching unit 104 determines that a blocking period t10 exists and determines that enhanced information A has been received before the start time t11 of the blocking period. Time t3, at which the validity period of this enhanced information A ends, is then determined as the first time tA. Next, enhanced information E is determined to begin receiving after the end time t12 of the blocking period t10, and the start time t5 of the validity period of enhanced information E is determined as the second time tB. Furthermore, because the second time tB (time t5) does not arrive before the first time tA (time t3), the positioning mode switching unit 104 determines that a period has occurred during which any of the enhanced information sequentially received by the positioning device 2 cannot be used, and outputs an instruction to the positioning device 2 to preemptively switch its positioning mode from the first to the second positioning mode.

[0061] Thus, the positioning device 2 switches the positioning method from the first positioning method to the second positioning method at time t3p before the first time tA (time t3), and performs positioning using the second positioning method until the second time tB (time t5).

[0062] Preferably, the positioning device 2 performs preliminary processing (such as establishing a communication link) for switching to the second positioning mode according to the instruction of the positioning mode switching unit 104 at time tp before the first time tA (time t3).

[0063] Furthermore, since the augmented information can be used from the second time tB (time t5), the positioning mode switching unit 104 outputs an instruction to the positioning device 2 to return the positioning mode of the positioning device 2 from the second positioning mode to the first positioning mode.

[0064] As a result, the positioning device 2 switches the positioning method from the second positioning method to the first positioning method at the second time tB (time t5 ), and performs positioning using the first positioning method from the second time tB (time t5 ).

[0065] (2) Maintain the first positioning mode exist Figure 4B In the example shown, blocking period t10 begins and ends midway through the reception of enhanced information B. Therefore, positioning device 2 cannot use enhanced information B. However, it can use enhanced information C starting at time t3, when enhanced information C, which begins receiving after blocking period t10, is received. Consequently, both the end of effective period A' of enhanced information A and the start of use of enhanced information C are at time t3.

[0066] exist Figure 4B In the example shown, the positioning mode switching unit 104 determines that a momentary blocking period t10 exists and determines that enhanced information A has been received before the start time t11 of blocking period t10. Time t3, at which the validity period of this enhanced information A ends, is then determined as the first time tA. Next, enhanced information C is determined to begin receiving after the end time t12 of blocking period t10, and the start time t3 of the validity period of enhanced information C is determined as the second time tB. Furthermore, since the second time tB (time t3) arrives before the first time tA (time t3), the positioning mode switching unit 104 determines that continuity between the validity periods of the multiple pieces of enhanced information sequentially received by positioning device 2 is maintained and outputs an instruction to maintain the first positioning mode to positioning device 2. Consequently, positioning device 2 performs positioning while maintaining the first positioning mode.

[0067] As described above, the vehicle's own position acquisition device 1 of this embodiment is mounted on the vehicle and switches between a first positioning method, wherein the first positioning method performs positioning based on reception information of positioning radio waves received from positioning satellites and enhancement information that enhances this reception information, and a second positioning method, wherein the second positioning method performs positioning based on this reception information and positioning assistance information received from a positioning server via a network. The vehicle's own position acquisition device 1 of this embodiment switches from the first positioning method to the second positioning method based on a period of obstruction during which the accuracy of the first positioning method is reduced and the period during which the enhancement information is valid.

[0068] The self-position acquisition device 1 of this embodiment ( Figure 1 ) Based on whether the enhanced information that can be used before and after the blocking period can be used continuously, that is, whether the effective period of the enhanced information that can be used before and after the blocking period is continuous ( Figure 2The first positioning mode is switched to the second positioning mode in S106 of the embodiment. The self-position acquisition device 1 of the present embodiment switches to the second positioning mode in the case that the effective period of the enhanced information that can be used before and after the blocking period is continuous ( Figure 2 The S106 is, Figure 3 、 Figure 4B ), since positioning can be continued by the first positioning method, the switch from the first positioning method to the second positioning method is not performed, and the first positioning method is maintained ( Figure 2 S110). Thus, the self-position acquisition device 1 of this embodiment can suppress the occurrence of useless switching from the first positioning method to the second positioning method. In addition, the self-position acquisition device 1 of this embodiment is used in the case where the effective period of the enhanced information that can be used before and after the blocking period is not continuous ( Figure 2 No, Figure 4A ), the first positioning method is switched to the second positioning method at the end of the validity period of the enhanced information that can be used before the blocking period ( Figure 2 S107), the second positioning method is switched to the first positioning method at the beginning of the effective period of the enhanced information that can be used after the blocking period ( Figure 2 S108). Thus, the self-position acquisition device 1 of this embodiment can maintain high-precision self-position acquisition without compromising positioning accuracy, while preventing unnecessary costs such as communication fees associated with the second positioning method. Therefore, the self-position acquisition device 1 of this embodiment can achieve stable, high-precision positioning while suppressing costs.

[0069] Furthermore, based on the blocking period and the validity period of the enhanced information, the self-position acquisition device 1 of this embodiment determines a first time tA, which is the end of the validity period of the enhanced information received before the blocking period, and a second time tB, which is the start of the validity period of the enhanced information received after the blocking period. The self-position acquisition device 1 of this embodiment compares the first time tA and the second time tB and switches from the first positioning mode to the second positioning mode.

[0070] The self-position acquisition device 1 of this embodiment ( Figure 1 ) by determining the first time tA and the second time tB ( Figure 2 S104 and S105), it is possible to specifically grasp the effective period of the enhanced information that can be used before and after the blocking period, and thus it is possible to accurately grasp the period during which positioning can be achieved using the first positioning method ( Figure 3 、 Figure 4A 、 Figure 4B). In addition, the self-position acquisition device 1 of this embodiment can also accurately grasp the period during which positioning cannot be performed by the first positioning method, and thus can set the period during which positioning cannot be performed by the first positioning method as the period during which positioning is performed by the second positioning method ( Figure 4A ). As a result, the self-position acquisition device 1 of this embodiment is less likely to cause unnecessary switching from the first positioning method to the second positioning method, and it is easy to maintain high-precision self-position acquisition without reducing positioning accuracy. Therefore, according to the self-position acquisition device 1 of this embodiment, it is possible to further reduce costs and stably perform high-precision positioning.

[0071] Furthermore, the own position acquisition device 1 of this embodiment maintains the first positioning method when the second time tB arrives before the first time tA, and switches to the second positioning method when the second time tB arrives after the first time tA.

[0072] The self-position acquisition device 1 of this embodiment ( Figure 1 ) arrives before the first moment tA by the second moment tB ( Figure 2 The S106 is, Figure 3 、 Figure 4B ), specifically, it indicates that the effective period of the enhanced information that can be used before and after the blocking period is continuous. In addition, the self-position acquisition device 1 of this embodiment reaches ( Figure 2 No. of S106, Figure 4A ), specifically indicating that the effective period of the enhanced information that can be used before and after the blocking period is discontinuous. The self-position acquisition device 1 of this embodiment can correctly distinguish the situation of maintaining the first positioning method ( Figure 2 S110) and the case where the first positioning mode is switched to the second positioning mode ( Figure 2 Thus, it is easy to prevent unnecessary switching from the first positioning method to the second positioning method. Therefore, according to the self-position acquisition device 1 of this embodiment, it is possible to further reduce costs and stably perform high-precision positioning.

[0073] Furthermore, the own position acquisition device 1 of the present embodiment defines the blocking period during which the sky above the own vehicle is blocked as the blocking period.

[0074] The self-position acquisition device 1 of this embodiment ( Figure 1 ) It is clear that the obstacle (obstruction factor) that blocks the positioning of the own vehicle exists above the own vehicle. Therefore, the own position acquisition device 1 of this embodiment can capture an appropriate object as an obstacle (obstruction factor), so it is easy to calculate the obstruction period ( Figure 2As a result, the self-position acquisition device 1 of this embodiment can also easily determine the first time tA and the second time tB according to the blocking period and the effective period of the reinforcement information ( Figure 2 Therefore, according to the self-position acquisition device 1 of this embodiment, it is possible to further reduce costs and stably perform high-precision positioning.

[0075] Furthermore, the self-position acquisition device 1 of this embodiment can further simplify the identification targets of the outside world recognition device 3. This can reduce the processing load, thereby increasing the speed of acquiring obstacle information and enabling the self-position acquisition device 1 to be constructed using cheaper hardware.

[0076] [Second embodiment] Next, use Figure 5 、 Figure 6 and Figure 7 Next, a self-position acquisition device 1 according to a second embodiment will be described. In the self-position acquisition device 1 according to the second embodiment, descriptions of the same configuration and operation as those of the self-position acquisition device 1 according to the first embodiment will be omitted.

[0077] The self-position acquisition device 1 of the second embodiment differs from the self-position acquisition device 1 of the first embodiment in that it further includes an inner boundary recognition device 4, a movement amount calculation unit 111, a state acquisition unit 112, and a calculation method switching unit 113.

[0078] In the first embodiment, the blocking period calculation unit 102 was described as having a function to calculate blocking periods for objects between the specific positioning satellite transmitting augmentation information and the receiving antenna. Furthermore, the blocking period calculation unit 102 of the second embodiment may also include a function to predict blocking periods for positioning satellites other than the specific positioning satellite. Specifically, the blocking period calculation unit 102 of the second embodiment can obtain the elevation and azimuth angles of each positioning satellite based on the reception information contained in the radio waves. Thus, the blocking period calculation unit 102 of the second embodiment can calculate blocking periods for positioning satellites other than the specific positioning satellite, similar to the specific positioning satellite transmitting augmentation information.

[0079] The self-position acquisition device 1 of the first embodiment acquires the vehicle's self-position using the first positioning method when there is no obstruction. On the other hand, during an obstruction period, the self-position acquisition device 1 of the first embodiment compares the first time tA with the second time tB. If the second time tB arrives after the first time tA, the self-position acquisition device 1 acquires the vehicle's self-position using the second positioning method. In this case, the vehicle's self-position is acquired by the position acquisition unit 101 as an estimated self-position obtained by interpolating the vehicle's movement relative to past positioning results. Therefore, even when the second positioning method is used, the accuracy of self-position acquisition during an obstruction period may be lower than when there is no obstruction.

[0080] Therefore, the self-position acquisition device 1 of the second embodiment solves the above-mentioned problem by calculating the self-vehicle movement amount for estimating the vehicle's self-position based on satellite positioning using positioning satellites that have not been obstructed, or calculating the self-vehicle movement amount for estimating the vehicle's self-position based on the wheel odometry method during the obstruction period.

[0081] Hereinafter, a description will be given of how the own-vehicle position acquisition device 1 according to the second embodiment calculates the own-vehicle movement amount for estimating the own-vehicle position.

[0082] The second embodiment of the self-position acquisition device 1 is based on the premise that the obstruction period calculation unit 102 can individually calculate the obstruction period of each positioning satellite and that the future driving path of the self-vehicle can be identified in the position acquisition unit 101. The device calculates the amount of movement of the self-vehicle based on positioning satellites that have not yet been obstructed. This calculation method is referred to as the first calculation method. As the first calculation method, the self-vehicle movement amount is calculated based on the selected positioning satellites that can be observed, have a margin until the obstruction period, and match the self-vehicle's orientation. The selected positioning satellites are those for which the time until the onset of the obstruction is greater than a specified value Tthr, and the self-vehicle's traveling orientation Dvehicle based on the driving path and the positioning satellite's azimuth angle Dsat are within a specified range Dthr. Specifically, as shown in the following equation 3, it is preferable to select positioning satellites whose angles relative to the direction of travel are within ±Dthr / 2, that is, those located in front of or behind the direction of travel. As shown in the following equation 4, it is more preferable to select positioning satellites whose angles relative to the direction of travel are within Dthr / 2, that is, those located behind the direction of travel. The "%" here indicates a remainder sign. [Formula 3] ∣Dvehicle-Dsat∣%180<Dthr [Formula 4] Dvehicle-Dsat%180<Dthr

[0083] As the first calculation method, it is preferable to use a known method for calculating the speed between a specific positioning satellite and the own vehicle (observer), such as a calculation method based on Doppler shift or a calculation method based on carrier phase difference. Alternatively, as the first calculation method, in order to stably determine the speed even when multipath exists in radio waves from some satellites, the speed between the own vehicle and a plurality of observable satellites may be calculated, and the own vehicle speed and movement direction may be calculated using the least squares method of the plurality of calculation results.

[0084] Figure 5 This is an explanatory diagram regarding the selection of positioning satellites when calculating the amount of movement of the own vehicle based on the positioning satellites.

[0085] use Figure 5 The calculation method of the first calculation method is schematically described. Assume that vehicle 10 is traveling upward in the figure, with pedestrian bridge 11 in front and building 12 to the right. Positioning satellites S1 to S4 are located around vehicle 10. Here, the positioning satellites selected when calculating vehicle speed using either the Doppler shift method or the carrier phase difference method are described. Positioning satellites that must be observable from vehicle 10 are eliminated from the list because they are obstructed by building 12. Positioning satellite S1, which will be obstructed in the near future, is likely to violate the constraint that the time until the obstruction begins is at least Tthr, and is therefore eliminated from the list. Positioning satellite S3 is likely to violate the constraint that the vehicle's travel direction and the positioning satellite's azimuth angle are within Dthr, and is therefore eliminated from the list. Positioning satellite S2, located behind vehicle 10 in its travel direction, satisfies all of the aforementioned constraints. Therefore, the first calculation method calculates the vehicle's speed based on positioning satellite S2, achieving highly accurate speed. Here, an example using only one satellite is described. However, if there are multiple positioning satellites that meet the conditions, they can also be used to calculate the speed using the least squares method or the like.

[0086] If there are no positioning satellites that meet the above conditions, the vehicle's movement amount is calculated using the well-known wheel odometry method, which estimates the relative motion of the vehicle based on the vehicle's steering angle and tire rotation. This calculation method is referred to as the second calculation method.

[0087] Figure 6 It is a block diagram showing a self-position acquisition device 1 according to the second embodiment.

[0088] like Figure 6 As shown in FIG. 1 , the self-position acquisition device 1 in the second embodiment is connected to the inner boundary recognition device 4. Figure 6As shown, the self-position acquisition device 1 of the second embodiment includes a movement amount calculation unit 111 , a state acquisition unit 112 , and a calculation method switching unit 113 .

[0089] The inner boundary recognition device 4 is mounted on the own vehicle and measures the movement of the own vehicle. As the inner boundary recognition device 4, it is intended to be a sensor type that measures the speed of the own vehicle, such as a millimeter wave radar, a wheel speed pulse sensor, an acceleration sensor, and an angular velocity sensor, as well as a sensor device that measures the posture of the own vehicle, such as an anti-skid system (ESC) and an inertial measurement unit (IMU). The inner boundary recognition device 4 can be set outside the own position acquisition device 1 or inside the own position acquisition device 1. The inner boundary recognition device 4 sends information related to the acquired movement of the own vehicle (hereinafter also referred to as own vehicle movement information) to the own position acquisition device 1.

[0090] The movement amount calculation unit 111 calculates the vehicle movement amount using either a first calculation method based on positioning satellites or a second calculation method based on wheel odometry. The vehicle behavior information obtained from the inner boundary recognition device 4 is used for wheel odometry.

[0091] The state acquisition unit 112 acquires the own vehicle behavior information sent from the inner boundary recognition device 4. The state acquisition unit 112 determines the accuracy state of the wheel odometry method based on the own vehicle behavior information. As the accuracy state of the wheel odometry method, if the tire torque does not change sharply even once within the specified time, it is determined that the accuracy state of the wheel odometry method is good. On the other hand, if the tire torque changes sharply multiple times within the specified time, or if the tire torque is less than usual within the specified time, it is estimated that the road surface is bumpy or prone to slipping, and it is determined that the accuracy state of the wheel odometry method is poor. The state acquisition unit 112 sends the information on the determined wheel odometry accuracy state to the calculation method switching unit 113.

[0092] As an example of the above-mentioned determination, the anti-skid device observes instantaneous changes in tire torque, or the acceleration sensor or vehicle speed sensor detects unevenness in the road surface. Based on these detection results, the status acquisition unit 112 determines that the wheel odometry accuracy is poor. Alternatively, for example, the output of a wheel speed pulse sensor may be compared with ground speed information from a millimeter-wave radar. Based on the compatibility between these different types of sensors, the status acquisition unit 112 determines the accuracy of the wheel odometry accuracy. Similarly, the status acquisition unit 112 may determine the accuracy of the wheel odometry accuracy based on the consistency between the amount of movement and angular change of the own vehicle obtained from the accumulated values of the sensor output of the inertial measurement unit and the amount of movement and angular change of the own vehicle obtained from the wheel speed pulse sensor and the steering angle sensor.

[0093] The calculation method switching unit 113 switches to a calculation method for calculating the amount of movement of the own vehicle based on the current state of the own vehicle, based on the information on the accuracy of the wheel odometry method obtained from the state acquisition unit 112 and information such as the elevation angle and azimuth of each positioning satellite obtained from the obstruction period calculation unit 102 of the second embodiment. In other words, the calculation method switching unit 113 switches to either the first calculation method or the second calculation method, taking into account the accuracy of the wheel odometry method and the degree of obstruction.

[0094] Figure 7 It means by Figure 6 1 is a flowchart of an example of a determination process of switching the own vehicle movement amount calculation method by the calculation method switching unit 113.

[0095] like Figure 7 As shown in FIG. 1 , the determination process of switching the own vehicle movement amount calculation method by the calculation method switching unit 113 is roughly as follows.

[0096] First, the calculation mode switching unit 113 determines whether there are a predetermined number of positioning satellites behind the vehicle in the direction of travel that can be used to calculate the vehicle's movement. If there are a predetermined number of positioning satellites behind the vehicle in the direction of travel that can be used to calculate the vehicle's movement, the calculation mode switching unit 113 switches the calculation mode to the first calculation mode.

[0097] If there are no predetermined number of positioning satellites behind the vehicle in the direction of travel that can be used to calculate the vehicle's movement, the calculation method switching unit 113 then determines whether the wheel odometry accuracy is satisfactory. If the wheel odometry accuracy is satisfactory, the calculation method switching unit 113 switches the calculation method to the second calculation method.

[0098] If the wheel odometry accuracy is not good, the calculation method switching unit 113 switches the calculation method to the first calculation method.

[0099] If the wheel odometry accuracy is acceptable for calculation of the vehicle's movement amount using the second calculation method, the calculation method switching unit 113 then determines whether a predetermined number of positioning satellites are available in the front-to-rear direction of the vehicle's travel that can be used to calculate the vehicle's movement amount. If the predetermined number of positioning satellites are available in the front-to-rear direction of the vehicle's travel that can be used to calculate the vehicle's movement amount, the calculation method switching unit 113 switches the calculation method to the first calculation method. If the predetermined number of positioning satellites are not available in the front-to-rear direction of the vehicle's travel that can be used to calculate the vehicle's movement amount, the calculation method switching unit 113 switches the calculation method to the second calculation method.

[0100] The determination process of switching the own vehicle movement amount calculation method by the calculation method switching unit 113 is specifically as follows.

[0101] The calculation method switching unit 113 counts the number N1 of positioning satellites that meet all of the following conditions (a) to (c) (step S201 ). (a) Observable from the own vehicle. (b) The time until the start of the blockage is equal to or longer than a predetermined value Tthr. (c) The azimuth angle relative to the vehicle's direction of travel is within Dthr / 2.

[0102] The calculation mode switching unit 113 determines whether the number of positioning satellites N1 counted in step S201 is greater than a predetermined first threshold value Nsat1 (step S202). The greater the number of positioning satellites N1 counted, the more accurately the vehicle's movement amount is calculated. If the number of positioning satellites N1 is less than the predetermined first threshold value Nsat1 ("No" in step S202), the calculation mode switching unit 113 proceeds to step S203. If the number of positioning satellites N1 is greater than the predetermined first threshold value Nsat1 ("Yes" in step S202), the calculation mode switching unit 113 proceeds to step S208.

[0103] The calculation mode switching unit 113 determines whether the indicator Ind of the wheel odometry accuracy state obtained from the state acquisition unit 112 is less than a predetermined first threshold value Det1 (step S203). The smaller the value of the indicator Ind of the wheel odometry accuracy state, the better the wheel odometry accuracy state. If the indicator Ind of the wheel odometry accuracy state is less than the predetermined first threshold value Det1 ("Yes" in step S203), the calculation mode switching unit 113 proceeds to step S207. If the indicator Ind of the wheel odometry accuracy state is greater than the predetermined first threshold value Det1 ("No" in step S203), the calculation mode switching unit 113 proceeds to step S204.

[0104] The calculation mode switching unit 113 determines whether the wheel odometry accuracy indicator Ind obtained from the status acquisition unit 112 is less than a predetermined second threshold value Det2 (step S204). The wheel odometry accuracy indicator Ind in step S204 is the same as the wheel odometry accuracy indicator Ind in step S203. Therefore, the wheel odometry accuracy indicator Ind is greater than the predetermined first threshold value Det1. If the wheel odometry accuracy indicator Ind is less than the predetermined second threshold value Det2 ("Yes" in step S204), the calculation mode switching unit 113 proceeds to step S205. If the wheel odometry accuracy indicator Ind is greater than the predetermined second threshold value Det2 ("No" in step S204), the calculation mode switching unit 113 proceeds to step S208. The predetermined second threshold value Det2 is a value that determines whether the wheel odometry accuracy is at a critical point that can be tolerated in the calculation of the vehicle's movement amount based on the second calculation mode.

[0105] The calculation method switching unit 113 counts the number N2 of positioning satellites that meet all of the following conditions (a), (b), and (d) (step S205 ). (a) Observable from the own vehicle. (b) The time until the start of the blockage is equal to or longer than a predetermined value Tthr. (d) The azimuth angle relative to the vehicle's direction of travel is within ±Dthr / 2.

[0106] The calculation mode switching unit 113 determines whether the number of positioning satellites N2 counted in step S205 is greater than or equal to a predetermined second threshold value Nsat2 (step S206). The greater the number of positioning satellites N2 counted, the more accurately the vehicle's movement amount is calculated. If the number of positioning satellites N2 is less than the predetermined second threshold value Nsat2 ("No" in step S206), the calculation mode switching unit 113 proceeds to step S207. If the number of positioning satellites N2 is greater than or equal to the predetermined second threshold value Nsat2 ("Yes" in step S206), the calculation mode switching unit 113 proceeds to step S208.

[0107] The calculation method switching unit 113 switches the calculation method to the second calculation method (step S207) when the indicator Ind of the accuracy state of the wheel odometry method is less than the specified first threshold Det1 ("Yes" in step S203) or when the number of positioning satellites N2 is less than the specified second threshold Nsat2 ("No" in step S206).

[0108] The calculation method switching unit 113 switches the calculation method to the first calculation method (step S208) when the number N1 of positioning satellites is greater than the prescribed first threshold value Nsat1 ("Yes" in step S202), the indicator Ind of the accuracy state of the wheel odometry method is greater than the prescribed second threshold value Det2 ("No" in step S204), or the number N2 of positioning satellites is greater than the prescribed second threshold value Nsat2 ("Yes" in step S206).

[0109] Furthermore, in steps S203 and S204, the values of the first threshold value Det1 and the second threshold value Det2, which are specified as comparison targets for the indicator Ind of the wheel odometry accuracy, can be changed. Specifically, before detection by the inner boundary recognition device 4, the outer boundary recognition device 3 measures the road surface condition and transmits the measured road surface condition information to the self-position acquisition device 1. The calculation mode switching unit 113 predicts the future wheel odometry accuracy based on the road surface condition information transmitted from the outer boundary recognition device 3. If the calculation mode switching unit 113 determines that the future wheel odometry accuracy is likely to deteriorate, it changes the values of the first threshold value Det1 and the second threshold value Det2 to smaller values.

[0110] As described above, the self-position acquisition device 1 of the second embodiment obtains information related to the accuracy status of the wheel odometry method through the inner boundary recognition device 4 mounted on the self-vehicle, as a calculation method for calculating the movement amount of the vehicle used to estimate the self-position during the obstruction period, according to the following formula 5 related to the number of positioning satellites and the following formula 6 related to the accuracy status of the wheel odometry method, when formula 5 is established, it switches to the first calculation method for calculating the movement amount of the vehicle based on the positioning satellites, and when formula 5 is not established, or when formula 6 is established, it switches to the second calculation method for calculating the movement amount of the vehicle based on the wheel odometry method. [Formula 5] N1≧Nsat 1 N1: The number of satellites that meet all of the following conditions: The number of positioning satellites that can be observed, The time until the blockage starts is longer than the specified value (Tthr). The vehicle's travel direction (Dvehicle) based on the driving path, the azimuth of the positioning satellite (Dsat), and the positioning satellite within the specified range (Dthr) correspond to the following relationship: Dvehicle-Dsat%180<Dthr, Among them, "%" represents the remainder symbol; Nsat 1: The first threshold value of the regulation related to the number of satellites. [Formula 6] Ind<Det1 Ind: Indicator of the accuracy status of the wheel odometry method Det1: The first threshold value of the wheel odometry accuracy status

[0111] The self-position acquisition device 1 ( Figure 6 ), during the blocking period, using a known measuring device and a known measuring method, the above formula 5 ( Figure 7 S201 and S202) and Equation 6 ( Figure 7 S203), can be based on the positioning satellite that can be observed ( Figure 5 The vehicle's own vehicle movement amount ( Figure 7 (S207 of 7 or S208 of 7). Thus, the self-position acquisition device 1 of the second embodiment can achieve highly accurate self-position acquisition even during an obstruction period by interpolating the calculated self-vehicle movement amount from previously calculated positioning results. Therefore, the self-position acquisition device 1 of this embodiment can further reduce costs and stably perform high-precision positioning.

[0112] Furthermore, the self-position acquisition device 1 of the second embodiment switches to the second calculation method when the above-mentioned Formulas 5 and 6 do not hold true, based on the following Formula 7 related to the accuracy state of the wheel odometry method and the following Formula 8 related to the number of positioning satellites. When Formula 7 holds true, the device switches to the first calculation method when Formula 7 does not hold true or Formula 8 holds true. [Formula 7] Det1≤Ind<Det2 Ind: indicator of the accuracy status of the wheel odometry method, Det1: a first threshold value related to the accuracy of the wheel odometry method, Det2: A prescribed second threshold value related to the accuracy state of the wheel odometry. [Formula 8] N2≥Nsat2 N2: The number of satellites that meet all of the following conditions: Positioning satellites that can be observed, The time until the blockage starts is longer than the specified value (Tthr). The vehicle's travel direction (Dvehicle) based on the driving path, the azimuth of the positioning satellite (Dsat), and the positioning satellite within the specified range (Dthr) correspond to the following relationship: ∣Dvehicle-Dsat∣%180<Dthr Among them, "%" represents the remainder symbol; Nsat 2: The second threshold value related to the number of satellites.

[0113] The self-position acquisition device 1 ( Figure 6 ), during the blocking period, using a known measuring device and a known measuring method, by the above formula 5 ( Figure 7 S201 and S202) and Equation 6 ( Figure 7 S203) is wider than the allowable range of formula 7 ( Figure 7 S204) and Equation 8( Figure 7 The vehicle's own movement amount (S205 and S206) can be calculated based on any preferred one of the observable positioning satellite and wheel odometry method for estimating the vehicle's own position. Figure 7 (S207 of 7 or S208 of 7). Thus, the self-position acquisition device 1 of the second embodiment can easily acquire the self-position with high accuracy even during an obstruction period by interpolating the calculated self-vehicle movement amount from previously calculated positioning results. Therefore, the self-position acquisition device 1 of this embodiment can further reduce costs and stably perform high-precision positioning.

[0114] Furthermore, the own position acquisition device 1 of the second embodiment changes the predetermined first threshold value related to the accuracy state of the wheel odometry method based on the road surface state obtained by the outside world recognition device 3 mounted on the own vehicle.

[0115] The self-position acquisition device 1 ( Figure 6 ) The calculation mode switching unit 113 determines in advance that the accuracy of the wheel odometry method may become poor during the obstruction period based on the road surface condition information measured by the external recognition device 3, and sets the first threshold value ( Figure 7 Therefore, the self-position acquisition device 1 of the second embodiment preferentially uses the first calculation method ( Figure 7 As a result, the self-position acquisition device 1 of the second embodiment can improve the judgment speed related to the calculation method and easily acquire the self-position with high accuracy using a known measurement device and known measurement method. Therefore, the self-position acquisition device 1 of this embodiment can further reduce costs and stably perform high-precision positioning.

[0116] [Third embodiment] Next, use Figure 8A self-position acquisition device 1 according to a third embodiment will be described. In the self-position acquisition device 1 according to the third embodiment, descriptions of the same configuration and operation as those of the self-position acquisition device 1 according to the first and second embodiments will be omitted.

[0117] The self-position acquisition device 1 of the third embodiment differs from the self-position acquisition devices 1 of the first and second embodiments in that it further includes a history storage unit 121 and a map 122, is capable of communicating with a map server 5, and is connected to a communication unit 6. While the self-position acquisition devices 1 of the first and second embodiments operate solely on the vehicle itself and in the same environment, the self-position acquisition device 1 of the third embodiment differs in that it maintains records as needed and communicates with the outside world.

[0118] Figure 8 It is a block diagram showing a self-position acquisition device 1 according to a third embodiment.

[0119] like Figure 8 As shown, the self-position acquisition device 1 of the third embodiment includes a history storage unit 121 and a map 122 .

[0120] The history storage unit 121 stores one or more of the blocking period and the effective period of the reinforcement information as past history, and transmits the stored past history to the blocking period calculation unit 102 .

[0121] Map 122 is a database containing information about objects surrounding each location. It may also record small obstacles such as buildings and man-made structures. Map 122 may also be a function of a well-known car navigation system installed in a vehicle. The location acquisition unit 101, the obstruction period calculation unit 102, and the calculation mode switching unit 113 can utilize the information contained in map 122.

[0122] For example, the position acquisition unit 101 may insert its acquired position into the map 122 to predict the vehicle's path based on the road information contained in the map 122. Furthermore, the obstruction period calculation unit 102 may also acquire object information from the map 122. Furthermore, the calculation method switching unit 113 may pre-acquire locations where obstructions may occur from the map 122 and, near these locations, change a predetermined threshold related to the number of satellites to prioritize the second calculation method over the first. Specifically, the first threshold Nsat1 and the second threshold Nsat2 for the number of positioning satellites N1 and N2 that meet the requirements are set to larger values. Furthermore, the second threshold Det2 for the indicator Ind for the wheel odometry accuracy is further increased. By either or both of the above methods, the second calculation method is prioritized over the first.

[0123] Map 122 may become outdated over time and may deviate from the actual environment structure. To address this issue, the self-position acquisition device 1 of the third embodiment can also be connected to an external map server 5. Map 122 can communicate with the map server 5 or exchange information using a recording medium, etc., to update information on buildings and other items.

[0124] like Figure 8 As shown, a communication unit 6 is connected to the self-position acquisition device 1 of the third embodiment.

[0125] The communication unit 6 is mounted on the vehicle itself and communicates with one or more of other vehicles, road equipment, and facilities. The communication unit 6 is preferably a device having a known V2X communication function.

[0126] In the third embodiment of the self-position acquisition device 1, a connected communication unit 6 communicates with one or more other vehicles, road equipment, and facilities to receive one or more pieces of information other than the self-vehicle, including information on objects observed outside the self-vehicle, slippery road conditions, and historically recorded content. The self-position acquisition device 1 of the third embodiment, connected to the communication unit 6, can also determine one or more of a blocking period and a validity period of reinforcement information based on the information received by the communication unit 6.

[0127] As described above, the self-position acquisition device 1 of the third embodiment stores one or more of the obstruction period and the effective period of the reinforcement information as past history.

[0128] The self-position acquisition device 1 ( Figure 8 ) By storing previously acquired obstruction periods and the validity period of the enhanced information in the history storage unit 121 and referencing them as past history, the obstruction period, first time tA, and second time tB can be calculated for a location different from the current location of the own vehicle, which would otherwise be impossible to calculate. Thus, the own position acquisition device 1 of the third embodiment can improve positioning accuracy and make advance decisions about switching positioning modes. Furthermore, when the referenced past history is from positioning performed in the second positioning mode, the own position acquisition device 1 of the third embodiment can prevent the recurrence of costs such as communication fees. Therefore, the own position acquisition device 1 of the third embodiment can further reduce costs and achieve stable, high-precision positioning.

[0129] Furthermore, the self-position acquisition device 1 of the third embodiment calculates the obstruction period using a map.

[0130] The self-position acquisition device 1 ( Figure 8 ), by using, for example, a function of a well-known car navigation system as map 122, it is possible to easily grasp the start time and magnitude of the obstruction, even for objects such as tunnels where obstructions occur continuously for a predetermined period of time or longer. Thus, the self-position acquisition device 1 of the third embodiment can more accurately calculate the obstruction period while utilizing a well-known function. Therefore, the self-position acquisition device 1 of the third embodiment can further reduce costs and achieve stable, high-precision positioning.

[0131] Furthermore, the self-position acquisition device 1 of the third embodiment updates the map 122 .

[0132] The self-position acquisition device 1 ( Figure 8 ) can prevent map 122 from degrading over time. Thus, the self-position acquisition device 1 of the third embodiment can acquire accurate object information from map 122 even when the object changes over time. As a result, the self-position acquisition device 1 of the third embodiment can accurately calculate the obstruction period even after the passage of time. Therefore, the self-position acquisition device 1 of the third embodiment can further reduce costs and achieve stable, high-precision positioning.

[0133] Furthermore, the self-position acquisition device 1 of the third embodiment can perform at least any one of the following: use information obtained from outside the own vehicle through communication with any one or more other vehicles, road equipment and facilities through the communication unit 6 mounted on the own vehicle to calculate the obstruction period; or obtain the validity period of enhanced information from enhanced information obtained from outside the own vehicle through communication with any one or more other vehicles, road equipment and facilities through the communication unit.

[0134] The self-position acquisition device 1 ( Figure 8 ), by using, for example, a device with known V2X communication capabilities as the communication unit 6 to communicate with one or more other vehicles, road equipment, and facilities, it is possible to obtain object information or enhanced information that the own vehicle cannot obtain. Thus, the own position acquisition device 1 of the third embodiment can improve positioning accuracy and, by utilizing object information or enhanced information that the own vehicle cannot yet obtain, can make a preemptive decision on switching positioning methods. Therefore, the own position acquisition device 1 of the third embodiment can achieve stable, high-precision positioning while further reducing costs.

[0135] Furthermore, the present invention is not limited to the above-described embodiments and includes various variations. For example, the above-described embodiments are described in detail to facilitate understanding of the present invention and are not necessarily limited to embodiments having all the described configurations. Configurations from other embodiments may replace portions of the configurations of certain embodiments, and configurations from other embodiments may be added to the configurations of certain embodiments. Furthermore, other configurations may be added, deleted, or substituted for portions of the configurations of each embodiment.

[0136] Furthermore, each of the aforementioned components, functions, processing units, and the like may also be implemented through hardware, for example, by designing some or all of them using integrated circuits. Furthermore, each of the aforementioned components, functions, and the like may also be implemented through software, by having a processor interpret and execute programs that implement the respective functions. Information such as programs, tapes, and files that implement the respective functions may be stored in a storage device such as a memory, a hard disk, or an SSD (solid state drive), or in a recording medium such as an IC card, SD card, or DVD.

[0137] In addition, the control lines and information lines are those considered necessary for the purpose of explanation, and do not necessarily represent all control lines and information lines in the product. In reality, it can be assumed that almost all components are connected to each other. Explanation of symbols

[0138] 1…self-position acquisition device, 2…positioning device, 3…external identification device, 21…first receiver, 22…second receiver, 23…third receiver, 24…positioning engine, 101…position acquisition unit, 102…obstruction period calculation unit, 103…effective period acquisition unit, 104…positioning mode switching unit, tA…first moment, tB…second moment.

Claims

1. A self-position acquisition device, mounted on a vehicle, that switches between a first positioning method and a second positioning method, wherein the first positioning method performs positioning based on reception information of positioning radio waves received from a positioning satellite and enhanced information that enhances the received information, and the second positioning method performs positioning based on the received information and positioning assistance information received from a positioning server via a network, wherein the self-position acquisition device is characterized in that: The first positioning method is switched to the second positioning method based on a period during which the accuracy of the first positioning method is impeded and a valid period of the enhanced information.

2. The self-position acquisition device according to claim 1, characterized in that: determining a first time and a second time based on the blocking period and the validity period of the enhanced information; The first moment is the moment when the validity period of the enhanced information received before the blocking period ends. The second time is the start time of the effective period of the enhanced information that is received after the end of the blocking period. Compare the first moment and the second moment, and switch the first positioning mode to the second positioning mode.

3. The self-position acquisition device according to claim 2, characterized in that: When the second moment arrives before the first moment, the first positioning mode is maintained. When the second moment arrives after the first moment, switch to the second positioning mode.

4. The self-position acquisition device according to claim 1, wherein: The obstruction period is a blocking period during which the sky above the own vehicle is blocked.

5. The self-position acquisition device according to claim 1, wherein: The information related to the accuracy of the wheel odometry method is obtained by the inner boundary recognition device installed on the vehicle. During the obstruction period, the amount of movement of the vehicle used to estimate its own position is calculated using the following formula 1 related to the number of positioning satellites and the following formula 2 related to the accuracy of the wheel odometry method: When Equation 1 holds true, the method switches to the first calculation method of calculating the vehicle's movement amount based on positioning satellites. When Equation 1 is not satisfied and Equation 2 is satisfied, the second calculation method based on the wheel odometry method is used to calculate the vehicle's movement amount. [Formula 1] N1≧Nsat1 N1: The number of satellites that meet all of the following conditions: Positioning satellites that can be observed, The time until the blockage starts is longer than the specified value (Tthr). The vehicle's travel direction (Dvehicle) based on the driving path, the azimuth of the positioning satellite (Dsat), and the positioning satellite within the specified range (Dthr) correspond to the following relationship: Dvehicle-Dsat%180<Dthr, Among them, "%" represents the remainder symbol; Nsat 1: The first threshold value of the regulation related to the number of satellites, [Formula 2] Ind<Det1 Ind: indicator of the accuracy status of the wheel odometry method, Det1: A prescribed first threshold value related to the accuracy state of the wheel odometry.

6. The self-position acquisition device according to claim 5, characterized in that: When equations 1 and 2 do not hold true, according to the following equation 3 related to the accuracy of the wheel odometry method and the following equation 4 related to the number of positioning satellites, When equation 3 holds true, switch to the second calculation method. When equation 3 is not true or equation 4 is true, switch to the first calculation method. [Formula 3] Det1≤Ind<Det2 Ind: indicator of the accuracy status of the wheel odometry method, Det1: a first threshold value related to the accuracy of the wheel odometry method, Det2: a second threshold value related to the accuracy of the wheel odometry method, [Formula 4] N2≥Nsat2 N2: The number of satellites that meet all of the following conditions: Positioning satellites that can be observed, The time until the blockage starts is longer than the specified value (Tthr). The vehicle's travel direction (Dvehicle) based on the driving path, the azimuth of the positioning satellite (Dsat), and the positioning satellite within the specified range (Dthr) correspond to the following relationship: ∣Dvehicle-Dsat∣%180<Dthr, Among them, "%" represents the remainder symbol; Nsat 2: The second threshold value related to the number of satellites.

7. The self-position acquisition device according to claim 5, characterized in that: Based on the road surface state obtained by an external environment recognition device mounted on the own vehicle, a predetermined first threshold value related to the accuracy state of the wheel odometry method is changed.

8. The self-position acquisition device according to claim 1, characterized in that , At least one of the blocking period and the effective period of the reinforcement information is stored as past history.

9. The self-position acquisition device according to claim 1, characterized in that , The blocking period is calculated using a map.

10. The self-position acquisition device according to claim 9, characterized in that , Updates said map.

11. The self-position acquisition device according to claim 1, wherein: Do at least one of the following: The obstruction period is calculated using information other than the own vehicle obtained by communicating with one or more of other vehicles, road equipment, and facilities through a communication unit mounted on the own vehicle; or The validity period of the enhanced information is acquired from enhanced information other than that of the own vehicle obtained by communicating with one or more of other vehicles, road equipment, and facilities through the communication unit.

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