Self-location acquisition device

Abstract

To provide a self-position acquisition device which enables stable, high-precision positioning while suppressing the cost.SOLUTION: A self-position acquisition device disclosed herein is configured to switch between a first positioning method for performing positioning based on signal reception information of positioning radio waves received from positioning satellites and reinforcement information for reinforcing the signal reception information, and a second positioning method for performing positioning based on the signal reception information and positioning auxiliary information received from a positioning server via a network, according to an inhibition period accompanying accuracy deterioration in the first positioning method and a validity period of the reinforcement information.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a self-location acquisition device. [Background technology]

[0002] Conventionally, there are known techniques for measuring the current position of a moving object. For example, there is a known standalone positioning method in which the vehicle itself determines its own position based on received information carried on radio waves received from a positioning satellite. There is also known a network-assisted method in which the vehicle itself determines its position based on the received information and positioning assistance information received from a positioning server via a network. Patent Document 1 discloses a technique that uses a combination of the above two positioning methods.

[0003] The technology in Patent Document 1 detects that a vehicle is located in a space with an enclosed top, or predicts that it will move in the near future, or switches the positioning method from a standalone positioning method to a network-assisted method when the quality of radio waves drops below a predetermined level. [Prior art documents] [Patent documents]

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

[0005] However, even in a closed space above, there are many cases where the line of sight between the positioning satellite and the vehicle may be momentarily blocked, such as on a pedestrian bridge, etc. Even in such cases, switching to the network-assisted method each time, as in the technology described in Patent Document 1, may result in excessive additional costs such as network usage fees.

[0006] The present invention has been made in consideration of the above, and aims to provide a self-positioning device that can perform stable, high-precision positioning while keeping costs down by minimizing the use of network-assisted methods and performing positioning using standalone positioning methods as much as possible. [Means for solving the problem]

[0007] In order to solve the above problem, the self-location obtaining device of the present invention is a self-location obtaining device mounted on a vehicle that switches between a first positioning method that performs positioning based on received information of positioning radio waves received from a positioning satellite and reinforcement information that reinforces the received information, and a second positioning method that performs positioning based on the received information and positioning auxiliary information received from a positioning server via a network, and is characterized in that it switches from the first positioning method to the second positioning method based on an inhibiting period during which accuracy decreases in the first positioning method and the validity period of the reinforcement information. [Effects of the Invention]

[0008] According to the present invention, by minimizing the use of the network-assisted method and performing positioning using a standalone positioning method as much as possible, it is possible to provide a self-positioning device that can perform stable, high-precision positioning while keeping costs down. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram illustrating the configuration of a self-location acquisition device according to a first embodiment. [Figure 2] 4 is a flowchart illustrating an example of the flow of a process for switching the positioning method performed by the self-positioning device shown in FIG. [Figure 3] FIG. 4 is a diagram illustrating the relationship between each frame of supplemental information and the validity period of the supplemental information according to the first embodiment. [Figure 4A] 5A and 5B are diagrams showing, in chronological order, the state of the validity period of the reinforcement information when reception of the reinforcement information is interrupted according to the first embodiment. [Figure 4B] 5A and 5B are diagrams showing, in chronological order, the state of the validity period of the reinforcement information when reception of the reinforcement information according to the first embodiment is interrupted for a short period of time. [Figure 5] FIG. 10 is an explanatory diagram regarding selection of a positioning satellite when calculating the amount of movement of the vehicle based on satellite positioning according to the second embodiment. [Figure 6] FIG. 10 is a block diagram illustrating the configuration of a self-position acquisition device according to a second embodiment. [Figure 7] 7 is a flowchart showing an example of a determination process performed by a calculation method switching unit shown in FIG. 6 to switch the method for calculating the amount of movement of the host vehicle. [Figure 8] FIG. 10 is a block diagram showing a self-location acquisition device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that components with 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] 1 is a block diagram illustrating the configuration of a self-location obtaining device 1 according to the first embodiment. The self-location obtaining device 1 is mounted on a vehicle, obtains the position of the vehicle relative to a driving route such as a straight road or a curve, as its own position, and transmits it to another device in the vehicle.

[0012] A positioning device 2 and an external environment recognition device 3 are connected to a self-location acquisition device 1.

[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 that augments the received information of the positioning radio waves from a positioning satellite other than the multiple positioning satellites, a third receiver 23 that receives positioning aiding information that augments the received information of the positioning radio waves from a positioning server via a network, and a positioning engine 24 that performs positioning calculations using either a first positioning method based on the received information of the positioning radio waves and the augmentation information, or a second positioning method based on the received information of the positioning radio waves and the positioning aiding information. The received information of the positioning radio waves includes at least one of the date and time when the positioning satellite transmitted the positioning radio waves, the position information of the positioning satellite itself, orbital information of the other positioning satellites, and ionospheric information.

[0014] The first receiver 21 and the second receiver 22 are GNSS receivers that receive positioning radio waves and augmentation information from positioning satellites such as GPS satellites and quasi-zenith satellites, and the third receiver 23 is a communication device for receiving positioning auxiliary information used in a positioning method generally known as network-type RTK-GNSS. The positioning engine 24 is configured, for example, by a microcontroller, and performs processing to calculate self-position information such as latitude, longitude, altitude, and time through positioning calculations and output this to the self-position acquisition device 1. The positioning device 2 also outputs the augmentation information acquired by the second receiver 22 to the self-position acquisition 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 information of positioning radio waves, in which case self-position information is calculated in the self-positioning device 1. The first receiver 21 and the second receiver 22 are not limited to being separate devices, but may be configured as an integrated unit within the same aircraft and configured to receive both positioning radio waves and augmentation information.

[0016] The first positioning method is a standalone positioning method that calculates the current position solely based on the positioning radio waves of positioning satellites. In the self-positioning device 1 according to this embodiment, the first positioning method is a positioning method that is used preferentially unless reception of the positioning radio waves is blocked and positioning becomes difficult. The first positioning method performs high-precision positioning by using augmentation information transmitted from specific positioning satellites through positioning augmentation information services such as CLAS (Centimeter Level Augmentation Service) and HAS (High Accuracy Service).

[0017] In the first positioning method, the amount of error for each factor, such as satellite clock error, satellite orbit error, satellite signal bias, and ionospheric delay error, contained in the augmentation information is acquired, and high-precision positioning is performed by correcting the received information of positioning radio waves received from multiple other positioning satellites using the amount of error for each factor.

[0018] In the first positioning method, it is necessary to continuously receive one frame of augmentation information. For example, in CLAS, it takes 30 seconds to receive one frame of augmentation information transmitted from the Quasi-Zenith Satellite System Michibiki. For example, if an obstacle such as a footbridge, overpass, or tunnel is placed between a specific positioning satellite transmitting the augmentation information and the receiving antenna of the positioning device 2 during reception of one frame of augmentation information, preventing the second receiver 22 from receiving the augmentation information, the augmentation information becomes unusable, and correction using the amount of error for each factor contained in the frame becomes impossible.

[0019] Furthermore, a feature of augmentation information is that even if reception of one frame is completed without interruption, the amount of error for each factor changes over time. Therefore, after a certain amount of time has passed since reception was completed, the augmentation information becomes unusable, and correction using the amount of error for each factor contained in the augmentation information frame becomes impossible. The time from completion of reception of the augmentation information until the augmentation information becomes unusable varies depending on the type of positioning augmentation information service and the expected positioning accuracy, but is often set to around 60 seconds.

[0020] The second positioning method is a network-assisted method that calculates the current position based on positioning assistance information received from a positioning server via a communication network and information received from positioning radio waves from positioning satellites. For example, the second positioning method can be the Real Time Kinematic (RTK) method, which performs positioning based on positioning radio waves from positioning satellites as well as observation information of positioning radio waves from a reference station installed or set near the vehicle. The RTK method eliminates positioning errors based on double phase difference and does not require continuous reception of augmentation information like the aforementioned positioning augmentation information service. The second positioning method requires continuous acquisition of observation information from the reference station via a communication line. Therefore, if a paid network is used for communication with the positioning server, communication fees will be incurred.

[0021] The external environment recognition device 3 is mounted on the vehicle and recognizes the external environment around the vehicle. The external environment recognition device 3 is primarily intended to be a type of sensor that measures the distance and positional relationship to an object, such as a stereo camera or LiDAR. In addition, the external environment recognition device 3 is preferably capable of observing the size and type of an object. The external environment recognition device 3 acquires information about objects (hereinafter also referred to as object information) such as a space where positioning accuracy is reduced due to the inability to receive augmentation information from a specific positioning satellite. The object information includes information about the distance to the object, and preferably includes information about the distance to the object, the arrival time for the vehicle to reach the object, the positional relationship between the vehicle and the object, the size of the object, and the type of object. The external environment recognition device 3 transmits the object information obtained by measurement to the self-position acquisition device 1.

[0022] In this embodiment, obstacles that block the space above the vehicle, such as pedestrian bridges and viaducts over the vehicle's path and buildings along the vehicle's path, are considered to be obstacles that block the space above the vehicle, i.e., external environmental obstacles that may block the space above the vehicle. The distance to the obstruction, the arrival time, the size of the obstruction, the positional relationship between the vehicle and the obstruction, and the type of obstruction are considered to be obstruction object information (hereinafter simply referred to as obstruction information). Note that "obstruction" refers to an external environmental factor blocking the space between the specific positioning satellite and the receiving antenna of each receiver, causing a decrease in positioning accuracy.

[0023] The self-location acquisition device 1 is configured by, for example, one or more microcontrollers equipped with a central processing unit (CPU), memories such as ROM and RAM, a timer, and an input / output unit. As shown in Fig. 1, the self-location acquisition device 1 is equipped with a position acquisition unit 101, an inhibition period calculation unit 102, a valid period acquisition unit 103, and a positioning method switching unit 104, and each of these units is realized by software processing of the microcontroller.

[0024] The position acquisition unit 101 acquires the self-position information of the vehicle from the positioning device 2. The position acquisition unit 101 transmits the acquired self-position information to another device in the vehicle. The position acquisition unit 101 may acquire, for example, latitude, longitude, altitude, time, etc., obtained by positioning calculation by the first receiver 21.

[0025] The position acquisition unit 101 may acquire self-position information of the vehicle from the external environment recognition device 3. For example, the self-position may be estimated based on a map and information such as signs, billboards, store exteriors, and road markings obtained by photographing the outside of the vehicle using the monocular camera of the external environment recognition device 3. Furthermore, self-position information obtained by observing the vehicle using a sensor installed on an infrastructure side independent from the vehicle may be acquired via wireless communication, optical communication, or communication via the Internet.

[0026] The inhibition period calculation unit 102 calculates an inhibition period during which accuracy decreases in the first positioning method for acquiring the vehicle's position. The inhibition period calculation unit 102 calculates the inhibition period by acquiring object information transmitted from the external environment recognition device 3. For example, a stereo camera is used to recognize obstacles that may block the path between a specific positioning satellite that transmits augmentation information and the receiving antenna of the positioning device 2, such as a pedestrian bridge or viaduct over the vehicle's travel path, and measure the distance and size of those obstacles.

[0027] The inhibition period calculation unit 102 obtains the elevation angle and azimuth angle of the specific positioning satellite transmitting the augmentation information by decoding the received positioning radio wave information from the specific positioning satellite transmitting the augmentation information. The inhibition period calculation unit 102 determines whether reception of the augmentation information is inhibited based on the distance from the vehicle to the object and the size of the object contained in the acquired object information, the elevation angle and azimuth angle of the specific positioning satellite obtained by decoding, and the vehicle speed and traveling direction of the vehicle. The inhibition period calculation unit 102 transmits the determination result to the positioning method switching unit 104.

[0028] When it is determined that reception of the reinforcement information is blocked, the inhibition period calculation unit 102 further calculates an inhibition start time based on the object information, mainly the distance to the object, the positional relationship between the host vehicle and the object, the host vehicle speed, the host vehicle traveling direction, and the elevation angle and azimuth angle of a specific positioning satellite. Next, it calculates an inhibition end time based on the inhibition start time and the object information, mainly the size and type of the object. The inhibition start time refers to the time when the object starts blocking reception of the reinforcement information. The inhibition end time refers to the time when the object ends blocking reception of the reinforcement information. The period from the inhibition start time to the inhibition end time is called the inhibition period. The inhibition period calculation unit 102 transmits information on the calculated inhibition period to the positioning method switching unit 104. The inhibition period can also be said to be a period during which the sky above the host vehicle is blocked.

[0029] Although a stereo camera has been used as an example of a means for recognizing obstacles, LiDAR may also be used, or the vehicle's position may be identified using another sensor such as a camera, and then the obstacle may be recognized by combining this with map information to calculate the obstruction start time and obstruction end time. Alternatively, the obstruction period may be received and acquired via external communication.

[0030] The inhibition period calculation unit 102 calculates the position of the host vehicle t seconds from now based on, for example, the distance to the object, the positional relationship between the host vehicle and the object, the host vehicle speed, and the traveling direction of the host vehicle, and determines whether the object will block the path between the specific positioning satellite and the receiving antenna based on the calculated host vehicle position and the elevation angle and azimuth angle of the specific positioning satellite. If it is determined that the object will block the path between the specific positioning satellite and the receiving antenna, the time t seconds from now is set as the inhibition start time.

[0031] When calculating the obstruction end time, the obstruction period calculation unit 102 may determine whether the obstruction is momentary or continuous for a predetermined period of time or longer depending on the type of object. That is, for objects that can be passed through in a short time, such as a signboard installed on a gantry, a footbridge, or a single-lane overpass, the obstruction is recognized as a momentary obstruction because the object passes underneath in a short time, for example, about one second, and (t+1) is set as the obstruction end time. On the other hand, for objects that last for a long time, for example, several tens of seconds or longer, such as a tunnel or a lower road of a multi-layered road, the obstruction is recognized as a continuous obstruction for a predetermined period of time or longer, and the value obtained by adding a certain value to t is set as the obstruction end time.

[0032] In addition, if a potential target such as an obstacle or obstruction cannot be observed on the vehicle's route, or if the target is far away or the vehicle is traveling at a slow speed and the target cannot be reached within a specified time, for example, within the frame length of the reinforcement information, the obstruction period may be calculated as not existing.

[0033] Furthermore, in order to reduce the processing load of image recognition, the recognition target may be simplified. For example, it may be possible to simply detect obstructions caused by obstructions above the vehicle.

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

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

[0036] The information included in the reinforcement information may deviate from the actual state over time, and if too much time passes, the information may deviate so much from the actual state that it becomes unusable. For this reason, the validity period acquisition unit 103 determines the validity period of the reinforcement information. The validity period of the reinforcement information is a period during which the deviation from the actual state is sufficient for the information to be usable, and in this embodiment, for example, is set to 60 seconds from the time when the reinforcement information is completely received.

[0037] The validity period of the augmentation information may be determined using the specification values ​​determined for each piece of information included in the augmentation information. For example, in the case of CLAS, the specification specifies that the satellite clock is 10 seconds, and information such as ionospheric correction, atmospheric correction, and satellite orbit is 60 seconds. However, since the augmentation information may gradually become less accurate over time, the validity period of the augmentation information may be set shorter when particularly high accuracy is required.

[0038] The validity period of the augmentation information may be changed in accordance with fluctuations in the error information, such as when fluctuations in the ionospheric delay error increase with the occurrence of a solar flare. Specifically, the validity period of the augmentation information may be set shorter during periods of active solar flares because ionospheric disturbances increase, and conversely, the validity period of the augmentation information may be set longer during periods of calm solar flares.

[0039] The positioning method switching unit 104 determines whether a period during which the reinforcement information received by the positioning device 2 cannot be used will occur, based on the inhibition period and the validity period of the reinforcement information. For example, if it is determined that the inhibition period is longer than the validity period of the reinforcement information and a period during which the reinforcement information cannot be used will occur, it outputs an instruction to the positioning device 2 to switch the positioning method of the positioning device 2 from the first positioning method to the second positioning method in advance. On the other hand, if it is determined that even if there is an inhibition period, it is within the validity period of the reinforcement information and no period during which the reinforcement information cannot be used will occur, it does not switch the positioning method and outputs an instruction to the positioning device 2 to maintain the first positioning method.

[0040] When switching the positioning method from the first positioning method to the second positioning method, the positioning device 2 needs time to establish a communication link and select a nearby reference station, or to transmit the latitude and longitude of the vehicle to the positioning server for generating positioning auxiliary information and wait for a response from the server. Therefore, the positioning method switching unit 104 outputs an instruction to the positioning device 2 to start pre-processing for switching to the second positioning method, such as establishing a communication link, at a timing prior to switching to the second positioning method.

[0041] When the inhibition period ends while the second positioning method is being executed and the reinforcement information becomes available, the positioning method switching unit 104 outputs an instruction to the positioning device 2 to perform processing to switch from the second positioning method to the first positioning method.

[0042] FIG. 2 is a flowchart showing an example of the flow of the positioning method switching process performed by the self-position obtaining device 1 shown in FIG.

[0043] The inhibition period calculation unit 102 of the self-location acquisition device 1 performs a process of acquiring augmentation information from the second receiver 22 (step S101). The acquired augmentation information is provided to the positioning method switching unit 104 via the validity period acquisition unit 103.

[0044] The inhibition period calculation unit 102 performs a process of calculating the inhibition period (step S102). The inhibition period calculation unit 102 determines the presence or absence of an object based on the object information obtained by the external environment recognition device 3, the elevation angle and azimuth angle of a specific positioning satellite obtained by decoding the reinforcement information, and information on the host vehicle's speed and traveling direction. Then, when an object is observed, the inhibition period calculation unit 102 calculates an inhibition period and provides information including the start time and end time of the inhibition period to the positioning method switching unit 104. When an object is not observed or when an object does not arrive within a predetermined time, the inhibition period calculation unit 102 provides information to the positioning method switching unit 104 that there is no inhibition period.

[0045] The positioning method switching unit 104 checks whether or not there is an inhibition period (step S103). If it is determined that there is an inhibition period (Yes in step S103), the unit identifies reinforcement information whose reception will be completed before the inhibition period, and identifies a first time tA, which is the time when the validity period of the identified reinforcement information will end (step S104). The positioning method switching unit 104 compares the inhibition start time with the reception completion time of the reinforcement information, and identifies the reinforcement information that is closest to the inhibition start time and whose reception will be completed before the inhibition period. Then, the unit performs a process of identifying the time when the validity period of the identified reinforcement information will end as the first time tA.

[0046] After identifying the first time tA, the positioning method switching unit 104 identifies a second time tB, which is the start time of the validity period of the reinforcement information that will start receiving after the end of the inhibition period (step S105). The positioning method switching unit 104 compares the inhibition end time of the inhibition period with the reception completion time of the reinforcement information, and identifies the reinforcement information that is closest to the inhibition end time and will start receiving after the inhibition end time. Then, for the identified reinforcement information, a process is performed to identify the start time of the validity period of the reinforcement information as the second time tB.

[0047] Specifically, the second time tB can be determined using the following formula. Assuming that the interference end time is trep, the period of one frame of reinforcement information is tint, and the time when the previous reinforcement information was received is told, the minimum P is first calculated using the following formula. Note that, as mentioned above, the interference end time and the period of the reinforcement information frame are known. [Number 1] trep <told+tint×P

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

[0049] After identifying the first time tA and the second time tB, the positioning method switching unit 104 performs a process of determining whether the second time tB will arrive by the first time tA (step S106). If it is determined that the second time tB will not arrive by the first time tA (No in step S106), that is, if it is determined that the second time tB will arrive after the first time tA, it determines that a period will occur during which none of the reinforcement information sequentially received by the positioning device 2 can be used, and outputs an instruction to the positioning device 2 to cause the positioning device 2 to execute a process of switching the positioning method of the positioning device 2 from the first positioning method to the second positioning method in advance (step S107). On the other hand, if it is determined that the second time tB will arrive before the first time tA (Yes in step S106), it is determined that continuity between the validity periods of each of the multiple reinforcement information can be ensured, and an instruction is output to the positioning device 2 to cause the positioning device 2 to perform processing to maintain the first positioning method (step S110).

[0050] The positioning method switching unit 104 outputs an instruction to switch the positioning method from the first positioning method to the second positioning method at the first time tA to the positioning device 2. Preferably, the positioning method switching unit 104 starts pre-processing for switching to the second positioning method, such as establishing a communication link, at a timing before the first time tA, and once the pre-processing is completed, outputs an instruction to the positioning device 2 to switch to the second positioning method before the first time tA arrives.

[0051] The positioning method switching unit 104 outputs an instruction to the positioning device 2 to switch back the positioning method from the second positioning method to the first positioning method at the timing of the second time tB (step S108). After the positioning method switches back from the second positioning method to the first positioning method, the positioning method switching unit 104 outputs an instruction to the positioning device 2 to cause the positioning device 2 to execute processing to disconnect the communication link used for the second positioning method (step S109).

[0052] 3 is a diagram showing the relationship between each frame of the reinforcement information and the validity period of the reinforcement information according to this embodiment. Times t1, t2, t3, t4, and t5 shown in Fig. 3 are divisions of fixed time periods, and although not shown, they continue without interruption after t5 during the operation of the self-location obtaining device 1 according to this embodiment.

[0053] A specific positioning satellite sequentially transmits unique augmentation information that is different from one another at predetermined time intervals. Each augmentation information is transmitted consecutively without interruption. Each augmentation 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. For example, in this embodiment, as shown in FIG. 3, the positioning device 2 sequentially receives augmentation information A, B, C, D, and E from a specific positioning satellite. Although not shown, the positioning device 2 continues to receive augmentation information after E without interruption. Upon completing reception of the previous augmentation information, the positioning device 2 starts receiving the next augmentation information consecutively. In the example shown in FIG. 3, when reception of augmentation information A is completed at time t1, reception of augmentation information B starts at the same time t1.

[0054] The validity period of the reinforcement information starts from the time when reception of one frame of the reinforcement information is completed. The length of the validity period of the reinforcement information is set so that the validity period of one reinforcement information and the validity period of the next reinforcement information partially overlap. For example, in this embodiment, the validity period of the reinforcement information is set to be twice the frame reception time for receiving one frame, and in the case of reinforcement information for which one frame's worth of reinforcement information has been successfully received consecutively by the positioning device 2, the validity period is from the time reception is completed to a time that is two frames' worth of frame reception time later.

[0055] 3, the latter half of the validity period A' of reinforcement information A overlaps with the first half of the validity period B' of reinforcement information B. The validity period A' of reinforcement information A is from time t1 to time t3, and the validity period B' of the subsequent reinforcement information B is from time t2 to time t4. For the portion where the validity period of one reinforcement information and the validity period of the next reinforcement information overlap, the self-location acquisition device 1 uses the next reinforcement information, which is fresher information, on the assumption that both pieces of reinforcement information have been received.

[0056] 3, there is no inhibited period, and no period during which the reinforcement information cannot be used. Therefore, the positioning method switching unit 104 does not output an instruction to switch the positioning method, and the first positioning method is maintained as the positioning method of the positioning device 2.

[0057] 4A and 4B are diagrams showing, in chronological order, the state of the validity period of the reinforcement information when reception of the reinforcement information according to this embodiment is interrupted.

[0058] The operations of the positioning method switching unit 104 according to this embodiment in (1) the pattern for switching to the second positioning method and (2) the pattern for maintaining the first positioning method will be described in detail below with reference to FIGS. 4A and 4B.

[0059] (1) Pattern for switching to the second positioning method 4A, the inhibition period t10 starts in the middle of receiving the reinforcement information B, and ends in the middle of receiving the reinforcement information D. Therefore, the positioning device 2 cannot use the reinforcement information B, C, and D, and can use the reinforcement information E from the reception completion time t5 of the reinforcement information E, which starts to be received after the inhibition period t10 ends. As a result, a period occurs in which the reinforcement information cannot be used, from the time t3 when the validity period A' of the reinforcement information A ends to the time t5 when the use of the reinforcement information E can start.

[0060] 4A , the positioning method switching unit 104 determines that there is an inhibition period t10, and identifies reinforcement information A whose reception will be completed before start time t11 of the inhibition period. Then, time t3, at which the validity period of the identified reinforcement information A ends, is identified as the first time tA. Next, reinforcement information E whose reception will begin after end time t12 of the inhibition period t10 is identified, and the validity period start time t5 of the reinforcement information E is identified as the second time tB. Then, because the second time tB (time t5) does not arrive by the first time tA (time t3), the positioning method switching unit 104 determines that a period will occur during which none of the reinforcement information sequentially received by the positioning device 2 can be used, and outputs an instruction to the positioning device 2 to switch the positioning method of the positioning device 2 from the first positioning method to the second positioning method in advance.

[0061] As a result, 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) arrives, and performs positioning using the second positioning method until the second time tB (time t5).

[0062] Preferably, the positioning device 2 performs pre-processing (such as establishing a communication link) for switching to the second positioning method in accordance with an instruction from the positioning method switching unit 104 at time tp, which is a timing before the first time tA (time t3).

[0063] Furthermore, since the period from the second time tB (time t5) onwards is a period in which the reinforcement information can be used, the positioning method switching unit 104 outputs an instruction to the positioning device 2 to switch the positioning method of the positioning device 2 back from the second positioning method to the first positioning method.

[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) Pattern that maintains the first positioning method 4B, the inhibition period t10 starts in the middle of receiving the reinforcement information B, and ends in the middle of receiving the reinforcement information B. Therefore, the positioning device 2 cannot use the reinforcement information B, and can use the reinforcement information C from the reception completion time t3 of the reinforcement information C, which starts to be received after the inhibition period t10 ends. As a result, the time when the validity period A' of the reinforcement information A ends and the time when the use of the reinforcement information C can start are both time t3.

[0066] In the example shown in FIG. 4B , the positioning method switching unit 104 determines that there is a momentary inhibition period t10, and identifies reinforcement information A whose reception is completed before start time t11 of the inhibition period t10. Then, time t3, at which the validity period of the identified reinforcement information A ends, is identified as the first time tA. Next, reinforcement information C whose reception begins after end time t12 of the inhibition period t10 is identified, and the start time t3 of the validity period of the reinforcement information C is identified as the second time tB. Then, the positioning method switching unit 104 determines that the second time tB (time t3) arrives before the first time tA (time t3), and therefore the continuity of the validity periods of the multiple pieces of reinforcement information sequentially received by the positioning device 2 can be ensured, and outputs an instruction to maintain the first positioning method to the positioning device 2. As a result, the positioning device 2 performs positioning while maintaining the first positioning method.

[0067] As described above, the self-location obtaining device 1 according to this embodiment is mounted on a vehicle and switches between a first positioning method that performs positioning based on reception information of positioning radio waves received from a positioning satellite and augmentation information that augments the reception information, and a second positioning method that performs positioning based on the reception information and positioning auxiliary information received from a positioning server via a network. The self-location obtaining device 1 according to this embodiment switches from the first positioning method to the second positioning method based on an inhibition period during which accuracy decreases in the first positioning method and the validity period of the augmentation information.

[0068] The self-location acquiring device 1 (FIG. 1) according to this embodiment switches from the first positioning method to the second positioning method based on whether available augmentation information is continuously available before and after the inhibition period, i.e., whether the validity periods of the available augmentation information are continuous before and after the inhibition period (S106 in FIG. 2). If the validity periods of the available augmentation information are continuous before and after the inhibition period (Yes in S106 in FIG. 2, FIGS. 3 and 4B), the self-location acquiring device 1 according to this embodiment can continue to perform positioning using the first positioning method, so it does not switch from the first positioning method to the second positioning method and maintains the first positioning method (S110 in FIG. 2). This allows the self-location acquiring device 1 according to this embodiment to prevent unnecessary switching from the first positioning method to the second positioning method. Furthermore, when the validity periods of the available reinforcement information before and after the inhibition period are not consecutive (No in S106 of FIG. 2, FIG. 4A), the self-location acquiring device 1 according to this embodiment switches from the first positioning method to the second positioning method when the validity period of the available reinforcement information before the inhibition period ends (S107 of FIG. 2), and switches from the second positioning method to the first positioning method when the validity period of the available reinforcement information after the inhibition period begins (S108 of FIG. 2). This allows the self-location acquiring device 1 according to this embodiment to maintain high-accuracy self-location acquisition without reducing positioning accuracy, and also prevents unnecessary costs, such as communication charges, incurred by the second positioning method. Therefore, the self-location acquiring device 1 according to this embodiment can perform stable, high-accuracy positioning while keeping costs down.

[0069] Furthermore, the self-location obtaining device 1 according to this embodiment identifies a first time tA, which is the time at which the validity period of the reinforcement information that completes reception before the inhibition period ends, and a second time tB, which is the start time of the validity period of the reinforcement information that starts reception after the inhibition period ends, based on the inhibition period and the validity period of the reinforcement information. The self-location obtaining device 1 according to this embodiment compares the first time tA with the second time tB, and switches from the first positioning method to the second positioning method.

[0070] The self-location acquiring device 1 (FIG. 1) according to this embodiment can specifically determine the validity period of the reinforcement information available before and after the inhibition period by identifying the first time tA and the second time tB (S104 and S105 in FIG. 2). Therefore, the self-location acquiring device 1 according to this embodiment can accurately determine the period during which positioning is possible using the first positioning method (FIGS. 3, 4A, and 4B). In addition, the self-location acquiring device 1 according to this embodiment can accurately determine the period during which positioning is impossible using the first positioning method. Therefore, the self-location acquiring device 1 according to this embodiment can set the period during which positioning is impossible using the first positioning method as the period during which positioning is possible using the second positioning method (FIG. 4A). This makes it less likely that unnecessary switching from the first positioning method to the second positioning method will occur, and makes it easier to maintain high-precision self-location without degrading positioning accuracy. Therefore, the self-location acquiring device 1 according to this embodiment can further perform stable, high-precision positioning while reducing costs.

[0071] Furthermore, the self-positioning device 1 according to this embodiment maintains the first positioning method if the second time tB arrives before the first time tA, and switches to the second positioning method if the second time tB arrives after the first time tA.

[0072] The self-location acquiring device 1 according to this embodiment (FIG. 1) specifically shows a state in which the validity period of the available reinforcement information is continuous before and after the inhibition period, because the second time tB arrives before the first time tA (Yes in S106 in FIG. 2, FIGS. 3 and 4B). Furthermore, the self-location acquiring device 1 according to this embodiment specifically shows a state in which the validity period of the available reinforcement information is not continuous before and after the inhibition period, because the second time tB arrives after the first time tA (No in S106 in FIG. 2, FIG. 4A). By specifically showing the comparison index between the first time tA and the second time tB, the self-location acquiring device 1 according to this embodiment can accurately distinguish between a case in which the first positioning method is maintained (S110 in FIG. 2) and a case in which the first positioning method is switched to the second positioning method (S107 in FIG. 2). This makes it easy to prevent unnecessary switching from the first positioning method to the second positioning method. Therefore, the self-position acquiring device 1 according to this embodiment can furthermore perform stable and highly accurate positioning while suppressing costs.

[0073] Furthermore, the self-position obtaining device 1 according to this embodiment defines a blocking period in which the sky above the vehicle is blocked as an obstruction period.

[0074] The self-location acquiring device 1 (FIG. 1) according to this embodiment clarifies that an obstacle (obstruction factor) that blocks the positioning of the vehicle exists in the air above the vehicle. This allows the self-location acquiring device 1 according to this embodiment to identify the appropriate object as the obstacle (obstruction factor), making it easy to calculate the obstruction period (S102 in FIG. 2). As a result, the self-location acquiring device 1 according to this embodiment can easily identify the first time tA and the second time tB from the obstruction period and the validity period of the reinforcement information (S104 and S105 in FIG. 2), making it easy to determine whether to perform positioning using the first positioning method or the second positioning method. Therefore, the self-location acquiring device 1 according to this embodiment further enables stable, high-precision positioning while reducing costs.

[0075] Furthermore, the self-location acquisition device 1 according to this embodiment can further simplify the recognition target of the external environment recognition device 3. This can reduce the processing load, thereby improving the speed at which inhibition factor information is acquired, and also enabling the self-location acquisition device 1 to be constructed using less expensive hardware.

[0076] [Second embodiment] Next, a self-location acquiring device 1 according to a second embodiment will be described with reference to Fig. 5, Fig. 6, and Fig. 7. In the self-location acquiring device 1 according to the second embodiment, the description of the same configuration and operation as those of the self-location acquiring device 1 according to the first embodiment will be omitted.

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

[0078] It has also been described that the inhibition period calculation unit 102 according to the first embodiment has a function of calculating an inhibition period for an object between a specific positioning satellite that transmits augmentation information and the receiving antenna. In addition, the inhibition period calculation unit 102 according to the second embodiment may also have a function of predicting inhibition for positioning satellites other than the specific positioning satellite. That is, the inhibition period calculation unit 102 according to the second embodiment can acquire the elevation angle and azimuth angle of each positioning satellite from reception information included in the radio waves. This allows the inhibition period calculation unit 102 according to the second embodiment to individually calculate the inhibition period for positioning satellites other than the specific positioning satellite, as well as for the specific positioning satellite that transmits augmentation information.

[0079] The position acquisition device 1 according to the first embodiment acquires the vehicle's position using the first positioning method when the vehicle is not obstructed. On the other hand, during an obstruction period, the position acquisition device 1 according to the first embodiment compares a first time tA with a second time tB, and acquires the vehicle's position using the second positioning method when the second time tB arrives after the first time tA. In this case, the position acquisition unit 101 acquires the vehicle's position as an estimated position obtained by interpolating the amount of movement of the vehicle from past positioning results. Therefore, even if the second positioning method is used, the accuracy of acquiring the vehicle's position during an obstruction period may be lower than when the vehicle is not obstructed.

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

[0081] Hereinafter, how the self-position obtaining device 1 according to the second embodiment calculates the amount of movement of the vehicle to estimate the self-position of the vehicle will be described.

[0082] The position acquisition device 1 according to the second embodiment calculates the vehicle movement amount based on positioning satellites that have not yet been blocked, on the premise that the blockage period calculation unit 102 can individually calculate the blockage period of each positioning satellite, and the position acquisition unit 101 can recognize the vehicle's future driving route. This calculation method is called the first calculation method. The first calculation method selects a positioning satellite that is observable, has a grace period until the blockage period begins, and is in accordance with the vehicle's heading, and calculates the vehicle movement amount based on the selected positioning satellite. The positioning satellite to be selected is one that can be observed, has a time until the start of blockage that is equal to or greater than a predetermined value Tthr, and whose vehicle traveling heading Dvehicle based on the driving route and azimuth angle Dsat of the positioning satellite are within a predetermined range Dthr. That is, it is preferable to select a positioning satellite whose angle with respect to the direction of travel is within ±Dthr / 2, i.e., in front of or behind the direction of travel, as shown in the following formula 3, and it is even more preferable to select a positioning satellite whose angle with respect to the direction of travel is within Dthr / 2, i.e., behind the direction of travel, as shown in the following formula 4. Note that "%" here means the remainder symbol. [Number 3] |Dvehicle-Dsat|%180 <Dthr [Number 4] Dvehicle-Dsat%180 <Dthr

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

[0084] FIG. 5 is an explanatory diagram regarding the selection of a positioning satellite when the amount of movement of the vehicle is calculated based on the positioning satellite.

[0085] The calculation method of the first calculation method will be explained using FIG. 5. Assume that the host vehicle 10 is traveling upward in the figure, with a pedestrian bridge 11 ahead and a building 12 on the right, and positioning satellites S1 to S4 present around the host vehicle 10. Here, the positioning satellites selected when calculating the host vehicle speed using either the method based on Doppler shift or the method based on carrier phase difference will be explained. From the viewpoint that the positioning satellite must be observable from the host vehicle 10, the positioning satellite S4 is excluded from the selection candidates because it is blocked by the building 12. The positioning satellite S1, which will be blocked in the near future, is excluded from the selection candidates because it may not satisfy the constraint that the time until the start of the blockage is equal to or longer than Tthr. The positioning satellite S3 is excluded from the selection candidates because it may not satisfy the constraint that the azimuth angle between the host vehicle's traveling direction and the positioning satellite is within Dthr. The positioning satellite S2, which is present behind the host vehicle 10 in the traveling direction, satisfies all of the above constraints. Therefore, the first calculation method can obtain a highly accurate speed by calculating the vehicle speed based on the positioning satellite S2. Here, an example using only one satellite has been described, but if there are multiple positioning satellites that satisfy the conditions, they may 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 movement amount is calculated based on the well-known wheel odometry method, which estimates the relative movement of the vehicle from the steering angle and tire rotation amount of the vehicle. This calculation method is called the second calculation method.

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

[0088] As shown in Fig. 6, an internal recognition device 4 is connected to the self-location acquisition device 1 according to the second embodiment. Also, as shown in Fig. 6, the self-location acquisition device 1 according to the second embodiment includes a movement amount calculation unit 111, a state acquisition unit 112, and a calculation method switching unit 113.

[0089] The internal environment recognition device 4 is mounted on the vehicle and measures the behavior of the vehicle. The internal environment recognition device 4 is intended to include sensors that measure the speed of the vehicle, such as millimeter-wave radar, wheel speed pulse sensors, acceleration sensors, and angular velocity sensors, as well as sensor devices that measure the attitude of the vehicle, such as an electronic stability control (ESC) and an inertial measurement unit (IMU). The internal environment recognition device 4 may be provided outside the self-location acquisition device 1 or may be provided within the self-location acquisition device 1. The internal environment recognition device 4 transmits the acquired information regarding the behavior of the vehicle (hereinafter also referred to as self-vehicle behavior information) to the self-location acquisition device 1.

[0090] The movement amount calculation unit 111 calculates the movement amount of the host vehicle using either a first calculation method based on positioning satellites or a second calculation method based on wheel odometry. The host vehicle behavior information obtained from the internal environment recognition device 4 is used to perform the wheel odometry.

[0091] The status acquisition unit 112 acquires the vehicle behavior information transmitted from the internal environment recognition device 4. The status acquisition unit 112 determines the accuracy state of the wheel odometry method based on the vehicle behavior information. Regarding the accuracy state of the wheel odometry method, if there is no sudden change in tire torque within a predetermined time, the accuracy state of the wheel odometry method is determined to be good. On the other hand, if there are sudden changes in tire torque multiple times within a predetermined time or if the tire torque is lower than normal for a predetermined time, it is estimated that the road surface is uneven or slippery, and the accuracy state of the wheel odometry method is determined to be bad. The status acquisition unit 112 transmits information about the determined wheel odometry accuracy state to the calculation method switching unit 113.

[0092] As an example of the above-mentioned determination, the status acquisition unit 112 may determine that the accuracy of the wheel odometry method is poor based on the detection results of an anti-skid device observing an instantaneous change in tire torque, or an acceleration sensor or a vehicle speed sensor detecting unevenness on the road surface. Alternatively, the status acquisition unit 112 may compare the output of a wheel speed pulse sensor with ground vehicle speed information obtained by a millimeter-wave radar, and determine the accuracy of the wheel odometry method based on the consistency between these different sensors. Similarly, the status acquisition unit 112 may determine the accuracy of the wheel odometry method based on the consistency between the host vehicle movement amount and angle change amount obtained from the integrated value of the sensor output of the inertial measurement unit and the host vehicle movement amount and angle change amount 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 the vehicle movement amount that is in line with the current state of the vehicle, based on information on the accuracy state of the wheel odometry method acquired from the status acquisition unit 112 and information such as the elevation angle and direction of each positioning satellite acquired from the inhibition period calculation unit 102 according to 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 inhibition.

[0094] FIG. 7 is a flowchart showing an example of a determination process performed by the calculation method switching unit 113 shown in FIG. 6 when switching the method for calculating the vehicle movement amount.

[0095] As shown in FIG. 7, the determination process performed by the calculation method switching unit 113 to switch the method for calculating the vehicle movement amount is roughly as follows.

[0096] First, the calculation method switching unit 113 determines whether there are a predetermined number of positioning satellites available for calculating the amount of movement of the vehicle behind the vehicle in the traveling direction. If there are a predetermined number of positioning satellites available for calculating the amount of movement of the vehicle behind the vehicle in the traveling direction, the calculation method switching unit 113 switches the calculation method to the first calculation method.

[0097] If there are not a predetermined number of positioning satellites available for calculating the vehicle movement amount behind the vehicle, the calculation method switching unit 113 then determines whether the wheel odometry method has good accuracy. If the wheel odometry method has good accuracy, the calculation method switching unit 113 switches the calculation method to the second calculation method.

[0098] If the accuracy state of the wheel odometry method is poor, then the calculation method switching unit 113 switches the calculation method to the first calculation method.

[0099] If the accuracy state of the wheel odometry method is in a state that can withstand calculation of the host vehicle movement amount using the second calculation method, then the calculation method switching unit 113 determines whether there are a predetermined number of positioning satellites that can be used to calculate the host vehicle movement amount in the forward / backward direction of the host vehicle traveling direction. If there are a predetermined number of positioning satellites that can be used to calculate the host vehicle movement amount in the forward / backward direction of the host vehicle traveling direction, the calculation method switching unit 113 switches the calculation method to the first calculation method. If there are not a predetermined number of positioning satellites that can be used to calculate the host vehicle movement amount in the forward / backward direction of the host vehicle traveling direction, the calculation method switching unit 113 switches the calculation method to the second calculation method.

[0100] The determination process performed by the calculation method switching unit 113 to switch the method for calculating the amount of movement of the vehicle 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) It must be observable from the vehicle. (b) The time until the onset of inhibition is equal to or greater than a predetermined value Tthr. (c) The azimuth angle is within Dthr / 2 relative to the vehicle's direction of travel.

[0102] The calculation method switching unit 113 determines whether the number N1 of positioning satellites counted in step S201 is equal to or greater than a predetermined first threshold Nsat1 (step S202). Note that the greater the value of the number N1 of positioning satellites counted, the higher the accuracy of the calculated vehicle movement amount. If the number N1 of positioning satellites is less than the predetermined first threshold Nsat1 (No in step S202), the calculation method switching unit 113 proceeds to step S203. If the number N1 of positioning satellites is equal to or greater than the predetermined first threshold Nsat1 (Yes in step S202), the calculation method switching unit 113 proceeds to step S208.

[0103] The calculation method switching unit 113 determines whether the index Ind of the accuracy state of the wheel odometry method acquired from the status acquisition unit 112 is less than a predetermined first threshold Det1 (step S203). Note that the smaller the numerical value of the index Ind of the accuracy state of the wheel odometry method, the better the accuracy state of the wheel odometry method. If the index Ind of the accuracy state of the wheel odometry method is less than the predetermined first threshold Det1 (Yes in step S203), the calculation method switching unit 113 proceeds to step S207. If the index Ind of the accuracy state of the wheel odometry method is equal to or greater than the predetermined first threshold Det1 (No in step S203), the calculation method switching unit 113 proceeds to step S204.

[0104] The calculation method switching unit 113 determines whether the index Ind of the accuracy state of the wheel odometry method acquired from the status acquisition unit 112 is less than a predetermined second threshold Det2 (step S204). Note that the index Ind of the accuracy state of the wheel odometry method in step S204 is the same as the index Ind of the accuracy state of the wheel odometry method in step S203. Therefore, the index Ind of the accuracy state of the wheel odometry method is equal to or greater than the predetermined first threshold Det1. If the index Ind of the accuracy state of the wheel odometry method is less than the predetermined second threshold Det2 (Yes in step S204), the calculation method switching unit 113 proceeds to step S205. If the index Ind of the accuracy state of the wheel odometry method is equal to or greater than the predetermined second threshold Det2 (No in step S204), the calculation method switching unit 113 proceeds to step S208. The predetermined second threshold value Det2 is a value that determines whether the accuracy of the wheel odometry method is sufficient to support the calculation of the host vehicle movement amount using the second calculation method.

[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) It must be observable from the vehicle. (b) The time until the onset of inhibition is equal to or greater than a predetermined value Tthr. (d) The azimuth angle is within ±Dthr / 2 relative to the vehicle's direction of travel.

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

[0107] If the index Ind of the accuracy state of the wheel odometry method is less than a predetermined first threshold Det1 (Yes in step S203), or if the number N2 of positioning satellites is less than a predetermined second threshold Nsat2 (No in step S206), the calculation method switching unit 113 switches the calculation method to the second calculation method (step S207).

[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 equal to or greater than a predetermined first threshold Nsat1 (Yes in step S202), when the index Ind of the accuracy state of the wheel odometry method is equal to or greater than a predetermined second threshold Det2 (No in step S204), or when the number N2 of positioning satellites is equal to or greater than a predetermined second threshold Nsat2 (Yes in step S206).

[0109] In steps S203 and S204, the values ​​of the first threshold Det1 and the second threshold Det2, which are defined as targets for comparison with the index Ind of the accuracy state of the wheel odometry method, can be changed. Specifically, before detection by the internal environment recognition device 4, the external environment recognition device 3 measures the road surface condition and transmits information about the measured road surface condition to the self-position acquisition device 1. The calculation method switching unit 113 predicts the future accuracy state of the wheel odometry method based on the information about the road surface condition transmitted from the external environment recognition device 3. If the calculation method switching unit 113 determines that the future accuracy state of the wheel odometry method may become poor, it decreases the values ​​of the first threshold Det1 and the second threshold Det2.

[0110] As described above, the self-position obtaining device 1 according to the second embodiment obtains information on the accuracy state of the wheel odometry method using the internal environment recognition device 4 mounted on the vehicle, and, during the obstruction period, switches to a calculation method for calculating the amount of movement of the vehicle to estimate the self-position, depending on the following formula 5 relating to the number of positioning satellites and the following formula 6 relating to the accuracy state of the wheel odometry method. If formula 5 holds, the method switches to a first calculation method that calculates the amount of movement of the vehicle based on the positioning satellites. If formula 5 does not hold or formula 6 holds, the method switches to a second calculation method that calculates the amount of movement of the vehicle based on the wheel odometry method. [Number 5] N1 ≥ Nsat1 N1: Number of satellites that meet all of the following conditions Positioning satellites that can be observed Time until the onset of inhibition is greater than or equal to a predetermined value (Tthr) The vehicle's heading based on the driving route (Dvehicle), the azimuth angle of the positioning satellite (D sat) and within a specified range (Dthr) satisfy the following relationship: Dvehicle-Dsat%180 <Dthr Here, "%" means the remainder symbol. Nsat1: a predetermined first threshold for the number of satellites [Number 6] Ind <Det1 Ind: Index of the accuracy status of the wheel odometry method Det1: A predetermined first threshold for the accuracy state of the wheel odometry method

[0111] The self-location obtaining device 1 (FIG. 6) according to the second embodiment can accurately calculate (S207 or S208 in FIG. 7) the amount of vehicle movement to estimate the vehicle's own position based on either observable positioning satellites (S2 in FIG. 5) or wheel odometry, as appropriate, using a known measurement device and a known measurement method during the inhibition period, using the above-described Equation 5 (S201 and S202 in FIG. 7) and Equation 6 (S203 in FIG. 7). As a result, the self-location obtaining device 1 according to the second embodiment can obtain the self-location with high accuracy by interpolating the calculated amount of vehicle movement based on previously calculated positioning results, even during the inhibition period. Therefore, the self-location obtaining device 1 according to this embodiment can further perform stable, high-precision positioning while reducing costs.

[0112] Furthermore, when the above-mentioned formulas 5 and 6 do not hold, the self-position acquisition device 1 according to the second embodiment switches to the second calculation method if formula 7 holds true, depending on the following formula 7 relating to the accuracy state of the wheel odometry method and the following formula 8 relating to the number of positioning satellites, and switches to the first calculation method if formula 7 does not hold true or formula 8 holds true. [Number 7] Det1≦Ind <Det2 Ind: Index of the accuracy status of the wheel odometry method Det1: A predetermined first threshold for the accuracy state of the wheel odometry method Det2: A predetermined second threshold for the accuracy state of the wheel odometry method [Number 8] N2 ≥ Nsat2 N2: Number of satellites that meet all of the following conditions Positioning satellites that can be observed Time until the onset of inhibition is greater than or equal to a predetermined value (Tthr) The vehicle's heading based on the driving route (Dvehicle), the azimuth angle of the positioning satellite (D sat) and within a specified range (Dthr) satisfy the following relationship: |Dvehicle-Dsat|%180 <Dthr Here, "%" means the remainder symbol. Nsat2: a second predetermined threshold for the number of satellites

[0113] The self-location acquiring device 1 (FIG. 6) according to the second embodiment can calculate the vehicle movement amount (S207 or S208 in FIG. 7) for estimating the vehicle's self-location based on either observable positioning satellites or wheel odometry, using a known measurement device and a known measurement method during the inhibition period, using Equation 7 (S204 in FIG. 7) and Equation 8 (S205 and S206 in FIG. 7), which have wider tolerance ranges than Equation 5 (S201 and S202 in FIG. 7) and Equation 6 (S203 in FIG. 7). This allows the self-location acquiring device 1 according to the second embodiment to easily acquire a highly accurate self-location even during the inhibition period by interpolating the calculated self-location amount based on previously calculated positioning results. Therefore, the self-location acquiring device 1 according to this embodiment can further perform stable, highly accurate positioning while reducing costs.

[0114] Furthermore, the self-position obtaining device 1 according to the second embodiment changes the predetermined first threshold value relating to the accuracy state of the wheel odometry method based on the road surface state obtained by the external environment recognition device 3 mounted on the vehicle.

[0115] The self-location acquiring device 1 (FIG. 6) according to the second embodiment determines in advance, based on road surface condition information measured by the external environment recognition device 3, that the accuracy state of the wheel odometry method may become poor during the inhibition period, and adjusts the predetermined first threshold value (S203 in FIG. 7) related to the accuracy state of the wheel odometry method to be smaller, using the calculation method switching unit 113. As a result, the self-location acquiring device 1 according to the second embodiment preferentially uses the first calculation method (S208 in FIG. 7) as the calculation method. As a result, the self-location acquiring device 1 according to the second embodiment can improve the speed of determining the calculation method and can easily acquire a highly accurate self-location using a known measurement device and a known measurement method. Therefore, the self-location acquiring device 1 according to this embodiment can further perform stable, highly accurate positioning while reducing costs.

[0116] [Third embodiment] Next, a self-location acquiring device 1 according to a third embodiment will be described with reference to Fig. 8. In the self-location acquiring device 1 according to the third embodiment, the description of the same configuration and operation as those of the self-location acquiring device 1 according to the first and second embodiments will be omitted.

[0117] The self-location obtaining device 1 according to the third embodiment differs from the self-location obtaining device 1 according to 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 further connected to a communication unit 6. The self-location obtaining device 1 according to the first and second embodiments operates on its own vehicle alone and performs the same operation in the same environment, but the self-location obtaining device 1 according to the third embodiment differs in that it keeps records as necessary and communicates with the outside.

[0118] FIG. 8 is a block diagram showing a self-position obtaining device 1 according to the third embodiment.

[0119] The self-position obtaining device 1 according to the third embodiment includes a history storage unit 121 and a map 122, as shown in FIG.

[0120] The history storage unit 121 stores at least one of the inhibition period and the validity period of the reinforcement information as a past history. The history storage unit 121 transmits the stored past history to the inhibition period calculation unit .

[0121] The map 122 is a database containing information about surrounding objects at each point, and may contain information about obstacles that do not change much, such as buildings and artificial structures, recorded in advance. The map 122 may be, for example, a function of a known car navigation system installed in a vehicle. The position acquisition unit 101, the inhibition period calculation unit 102, and the calculation method switching unit 113 are capable of using the information contained in the map 122.

[0122] For example, the position acquisition unit 101 may insert the acquired own position into the map 122 to predict the travel path of the vehicle based on road information included in the map 122. The inhibition period calculation unit 102 may acquire object information from the map 122. The calculation method switching unit 113 may acquire points where an inhibition may occur from the map 122 in advance, and may change a predetermined threshold related to the number of satellites so that the second calculation method is used preferentially over the first calculation method near the acquired points. Specifically, the first threshold Nsat1 and the second threshold Nsat2 for the numbers N1 and N2 of positioning satellites that meet the conditions are set to larger values. The second threshold Det2 for the index Ind of the accuracy state of the wheel odometry method is also set to larger values. The second calculation method is used preferentially over the first calculation method by either or both of the above.

[0123] There is a concern that the content of the map 122 will become outdated over time, resulting in a deviation from the actual environmental structure. To address this issue, the self-location acquisition device 1 according to the third embodiment may be connectable to an external map server 5. The map 122 may communicate with the map server 5 or exchange information using a recording medium or the like to update information about buildings and the like that it includes.

[0124] As shown in FIG. 8, a communication unit 6 is connected to the self-position obtaining device 1 according to the third embodiment.

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

[0126] In the self-location obtaining device 1 according to the third embodiment, the connected communication unit 6 communicates with one or more of other vehicles, road equipment, and facilities, and receives information obtained by a party other than the own vehicle, including one or more of object information observed by a party other than the own vehicle, road surface slippage conditions, and content recorded as history. The self-location obtaining device 1 according to the third embodiment, which is connected to the communication unit 6, may determine one or more of an obstruction period and a validity period of reinforcement information based on the information received by the communication unit 6.

[0127] As described above, the self-location obtaining device 1 according to the third embodiment stores at least one of the inhibition period and the validity period of the reinforcement information as a past history.

[0128] The self-location acquiring device 1 according to the third embodiment (FIG. 8) stores previously acquired inhibition periods and validity periods of reinforcement information in the history storage unit 121 and refers to them as past history, thereby being able to calculate the inhibition period, the first time tA, and the second time tB for a position different from the vehicle's current position, which would not be possible to calculate otherwise. This allows the self-location acquiring device 1 according to the third embodiment to improve positioning accuracy and also to determine in advance whether to switch the positioning method. In addition, the self-location acquiring device 1 according to the third embodiment can prevent costs such as communication fees from being incurred again if the past history to be referenced is from when positioning was performed using the second positioning method. Therefore, the self-location acquiring device 1 according to the third embodiment further enables stable, high-precision positioning while reducing costs.

[0129] Furthermore, the self-location obtaining device 1 according to the third embodiment calculates the inhibition period using a map.

[0130] The self-location obtaining device 1 according to the third embodiment (FIG. 8) uses, for example, a function of a known car navigation system as the map 122, so that it is possible to easily grasp the obstruction start time and the size of an object that causes continuous obstruction for a predetermined period of time or more, such as a tunnel. This allows the self-location obtaining device 1 according to the third embodiment to more accurately calculate the obstruction period by utilizing a known function. Therefore, the self-location obtaining device 1 according to the third embodiment further enables stable and high-precision positioning while suppressing costs.

[0131] Furthermore, in the self-position obtaining device 1 according to the third embodiment, the map 122 is updated.

[0132] The self-location acquiring device 1 (FIG. 8) according to the third embodiment can prevent the map 122 from deteriorating over time. As a result, the self-location acquiring device 1 according to the third embodiment can acquire accurate object information from the map 122 even if the object changes over time. As a result, the self-location acquiring device 1 according to the third embodiment can accurately calculate the inhibition period even over time. Therefore, the self-location acquiring device 1 according to the third embodiment can further perform stable, high-precision positioning while suppressing costs.

[0133] Furthermore, the self-location obtaining device 1 of the third embodiment performs at least one of the following: calculates the obstruction period using information obtained by a party other than the own vehicle, which is obtained by the communication unit 6 mounted on the own vehicle communicating with one or more of other vehicles, road equipment, and facilities; or obtains the validity period of the reinforcement information from reinforcement information obtained by a party other than the own vehicle, which is obtained by the communication unit communicating with one or more of other vehicles, road equipment, and facilities.

[0134] The self-location obtaining device 1 (FIG. 8) according to the third embodiment can obtain object information and reinforcing information that cannot be obtained by the vehicle itself by using, as the communication unit 6, for example, a device equipped with a known V2X communication function, which communicates with one or more of other vehicles, road equipment, and facilities. This allows the self-location obtaining device 1 according to the third embodiment to improve the accuracy of positioning, and also to determine in advance whether to switch the positioning method by using the object information and reinforcing information that the vehicle itself cannot yet obtain. Therefore, the self-location obtaining device 1 according to the third embodiment can further perform stable, high-precision positioning while suppressing costs.

[0135] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0136] Furthermore, the above-described configurations, functions, processing units, processing means, etc. may be partially or entirely realized by hardware, for example, by designing them as integrated circuits. The above-described configurations, functions, etc. may also be realized by software, in which a processor interprets and executes a program that realizes each function. Information such as the program, tape, and file that realizes each function can be stored in a memory, a recording device such as a hard disk or solid state drive (SSD), or a recording medium such as an IC card, SD card, or DVD.

[0137] In addition, the control lines and information lines shown are those that are considered necessary for the explanation, and do not necessarily show all the control lines and information lines in the product. In reality, it can be assumed that almost all components are interconnected. [Explanation of symbols]

[0138] REFERENCE SIGNS LIST 1 ···Self-position acquisition device, 2···Positioning device, 3···External environment recognition device, 21···First receiver, 22···Second receiver, 23···Third receiver, 24···Positioning engine, 101···Position acquisition unit, 102···Inhibition period calculation unit, 103···Valid period acquisition unit, 104···Positioning method switching unit, tA···First time, tB···Second time

Claims

1. A self-positioning device mounted on a vehicle switches between a first positioning method that performs positioning based on reception information of positioning radio waves received from a positioning satellite and augmentation information that augments the reception information, and a second positioning method that performs positioning based on the reception information and positioning auxiliary information received from a positioning server via a network, A self-location obtaining device, characterized in that the first positioning method is switched to the second positioning method based on an inhibiting period during which accuracy in the first positioning method decreases and a validity period of the reinforcement information.

2. Based on the inhibition period and the validity period of the reinforcement information, a first time that is a time at which a validity period of the reinforcement information that completes reception before the inhibition period ends; a second time that is a start time of a validity period of the reinforcement information that starts receiving after the end of the inhibition period; The self-position obtaining device according to claim 1 , wherein the first time and the second time are compared to switch the first positioning method to the second positioning method.

3. If the second time arrives before the first time, the first positioning method is maintained; 3. The self-location obtaining device according to claim 2, wherein when the second time arrives after the first time, the self-location obtaining device switches to the second positioning method.

4. 2. The self-position obtaining device according to claim 1, wherein the obstruction period is a blocking period in which the sky above the vehicle is blocked.

5. An internal environment recognition device mounted on the vehicle acquires information about the accuracy state of the wheel odometry method, During the obstruction period, a calculation method for calculating the amount of movement of the vehicle for estimating the vehicle's own position is performed according to the following formula 1 relating to the number of positioning satellites and the following formula 2 relating to the accuracy of the wheel odometry method: If Equation 1 is satisfied, the method switches to a first calculation method that calculates the amount of movement of the vehicle based on the positioning satellite; 2. The self-position obtaining device according to claim 1, wherein when formula 1 is not true but formula 2 is true, the self-position obtaining device switches to a second calculation method that calculates the amount of movement of the vehicle based on a wheel odometry method. [Equation 1] N1 ≧ Nsat1 N1: Number of satellites that meet all of the following conditions Positioning satellites that can be observed The time until the onset of inhibition is greater than or equal to a predetermined value (Tthr) The vehicle's heading based on the travel route (Dvehicle), the azimuth angle of the positioning satellite (D sat) and a positioning satellite within a predetermined range (Dthr) that satisfies the following relationship: Dvehicle-Dsat%180<Dthr Here, "%" means the remainder symbol. Nsat1: a predetermined first threshold for the number of satellites [Equation 2] Ind<Det1 Ind: Index of the accuracy of the wheel odometry method Det1: A predetermined first threshold value for the accuracy state of the wheel odometry method

6. When the formulas 1 and 2 are not satisfied, the following formula 3 regarding the accuracy of the wheel odometry method and the following formula 4 regarding the number of positioning satellites are used: If Equation 3 is satisfied, the second calculation method is used.

6. The self-position obtaining device according to claim 5, wherein when the formula 3 is not satisfied or the formula 4 is satisfied, the self-position obtaining device switches to the first calculation method. [Equation 3] Det1≦Ind<Det2 Ind: Index of the accuracy of the wheel odometry method Det1: A predetermined first threshold value for the accuracy state of the wheel odometry method Det2: A predetermined second threshold value for the accuracy state of the wheel odometry method. [Equation 4] N2 ≧ Nsat2 N2: Number of satellites that meet all of the following conditions Positioning satellites that can be observed The time until the onset of inhibition is greater than or equal to a predetermined value (Tthr) The vehicle's heading based on the travel route (Dvehicle), the azimuth angle of the positioning satellite (D sat) and a positioning satellite within a predetermined range (Dthr) that satisfies the following relationship: |Dvehicle-Dsat|%180<Dthr Here, "%" means the remainder symbol. Nsat2: a predetermined second threshold for the number of satellites

7. 6. The self-position obtaining device according to claim 5, wherein the predetermined first threshold value relating to the accuracy state of the wheel odometry method is changed based on the road surface state obtained by an external environment recognition device mounted on the vehicle.

8. 2. The self-location acquisition device according to claim 1, wherein at least one of the inhibition period and the validity period of the reinforcement information is stored as a past history.

9. The self-location acquisition device according to claim 1 , wherein the inhibition period is calculated using a map.

10. The self-location obtaining device according to claim 9, wherein the map is updated.

11. A communication unit mounted on the vehicle calculates the inhibition period using information acquired by a device other than the vehicle, the information being obtained by communicating with one or more of other vehicles, road equipment, and facilities, or The self-location acquisition device according to claim 1, characterized in that the communication unit acquires at least one of the following: a validity period of the reinforcement information from reinforcement information acquired by a vehicle other than the vehicle itself, which is obtained by communicating with one or more of other vehicles, road equipment, and facilities.

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