Patent Publication Number: US-2023136133-A1

Title: Parking assistance system, parking assistance device, parking assistance method, and non-transitory computer readable medium

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation application of International Patent Application No. PCT/JP2021/023041 filed on Jun. 17, 2021, which designated the U.S. and claims the benefit of priority from Japanese Patent Application No. 2020-122104 filed on Jul. 16, 2020. The entire disclosures of all of the above applications are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a parking assistance system, a parking assistance device, a parking assistance method, and a non-transitory computer readable medium storing a parking assistance program configured to assist in automatic valet parking of a vehicle. 
     BACKGROUND 
     As a parking assistance system, an automatic valet parking technique is well-known in which a management device on a parking lot side guides an autonomous vehicle from an alighting area to a parking area within a parking area. 
     SUMMARY 
     One aspect of the present disclosure provides a parking assistance system configured to assist in automatic valet parking of a vehicle. The parking assistance system includes an autonomous vehicle configured to perform autonomous driving between a boarding-alighting area and a parking area in a parking lot; and a management device configured to manage entering and exiting of an autonomous vehicle in the parking lot. 
     The management device includes a route generation unit, a map provision unit, and a route provision unit. The route generation unit configured to generate a guide route from the boarding-alighting area to the parking area that is a target position when a entering instruction for entering the autonomous vehicle is input while the autonomous vehicle is located in the boarding-alighting area. 
     The map provision unit is configured to extract a route map representing parking lot map information of a portion related to the guide route from previously prepared parking lot map information including positions of a passage of the parking lot, the boarding-alighting area, and the parking area, and provide the route map to the autonomous vehicle. The route provision unit configured to provide the guide route to the autonomous vehicle. 
     The map provision unit is a first provision unit. The management device further includes a second provision unit configured to provide the autonomous vehicle with a near-side map representing parking lot map information of a portion from a near-side region set in advance to the boarding-alighting area in the parking lot map information when the autonomous vehicle is located in the near-side region before the entering instruction is input and before the autonomous vehicle arrives at the boarding-alighting area. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a top view illustrating an example of a parking lot. 
         FIG.  2    is a block diagram illustrating a configuration of a parking assistance system. 
         FIG.  3    is a functional block diagram of a control unit of a management device. 
         FIG.  4    is a flowchart illustrating a movement management process executed by the management device. 
         FIG.  5    is a flowchart illustrating a movement setting process executed by the management device. 
         FIG.  6    is a flowchart illustrating an automatic parking process executed by an autonomous vehicle. 
         FIG.  7    is a flowchart illustrating a map information update process executed by the autonomous vehicle. 
         FIG.  8 A  is a diagram exemplifying the entire route of the parking lot map information regarding a guide route. 
         FIG.  8 B  is a diagram illustrating a first portion of the parking lot map information regarding the guide route. 
         FIG.  8 C  is a diagram illustrating a second portion of the parking lot map information regarding the guide route. 
         FIG.  8 D  is a diagram illustrating a third portion of the parking lot map information regarding the guide route. 
         FIG.  9 A  is a top view illustrating an example of division of parking lot map information regarding a guide route. 
         FIG.  9 B  is a diagram illustrating the first portion of the parking lot map information regarding the guide route. 
         FIG.  9 C  is a diagram illustrating the second portion of the parking lot map information regarding the guide route. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     To begin with, a relevant technology will be described first only for understanding the following embodiments. 
     Typically, an autonomous vehicle is configured to travel along a guide route transmitted from the management device. 
     In the above technique, it is preferable that the autonomous vehicle is provided with parking lot map information indicating positions of passages and the like in the parking lot such that the autonomous vehicle can travel safely. However, as a result of detailed studies by the inventor, a problem has been found in which parking lot map information has a huge amount of data, and if all of the parking lot map information is stored in an autonomous vehicle, and a capacity of a memory of the autonomous vehicle becomes tight. 
     One aspect of the present disclosure is to achieve a technique that in a parking assistance system configured to assist in automatic valet parking of a vehicle, when parking lot map information is stored in an autonomous vehicle, a capacity of a memory of the autonomous vehicle is less likely to be tight. 
     A first aspect of the present disclosure is a parking assistance system configured to assist in automatic valet parking of a vehicle. The parking assistance system includes an autonomous vehicle configured to perform autonomous driving between a boarding-alighting area and a parking area in a parking lot; and a management device configured to manage entering and exiting of the autonomous vehicle in the parking lot. The management device includes: a route generation unit configured to generate a guide route from the boarding-alighting area to the parking area that is a target position when an entering instruction for the autonomous vehicle to park is input while the autonomous vehicle is located in the boarding-alighting area; a map provision unit configured to (i) extract a route map from previously prepared parking lot map information including position information of a passage of the parking lot, the boarding-alighting area, and the parking area and (ii) provide the route map to the autonomous vehicle, the route map being indicative of a portion of the parking lot map information regarding the guide route; and a route provision unit configured to provide the guide route to the autonomous vehicle. The map provision unit is a first provision unit, and the management device further includes a second provision unit configured to provide the autonomous vehicle with a near-side map indicative of a portion of the parking lot map information from a near-side region set in advance to the boarding-alighting area when the autonomous vehicle is located in the near-side region and before the entering instruction is input and the autonomous vehicle arrives at the boarding-alighting area. 
     A second aspect of the present disclosure is a parking assistance device configured to assist in automatic valet parking of a vehicle. The vehicle is an autonomous vehicle configured to perform autonomous driving between a boarding-alighting area and a parking area in a parking lot. The parking assistance device includes: a route generation unit configured to generate a guide route from the boarding-alighting area to the parking area that is a target position when a entering instruction for the autonomous vehicle to park is input while the autonomous vehicle is located in the boarding-alighting area; a map provision unit configured to (i) extract a route map from previously prepared parking lot map information including position information of a passage of the parking lot, the boarding-alighting area, and the parking area and (ii) provide the route map to the autonomous vehicle, the route map being indicative of a portion of the parking lot map information regarding the guide route; and a route provision unit configured to provide the guide route to the autonomous vehicle. The map provision unit is a first provision unit, and the management device further includes a second provision unit configured to provide the autonomous vehicle with a near-side map indicative of a portion of the parking lot map information from a near-side region set in advance to the boarding-alighting area when the autonomous vehicle is located in the near-side region and before the entering instruction is input and the autonomous vehicle arrives at the boarding-alighting area. 
     A third aspect of the present disclosure is a parking assistance method executed by a parking assistance device configured to assist in automatic valet parking of a vehicle. The vehicle is an autonomous vehicle configured to perform autonomous driving between a boarding-alighting area and a parking area in a parking lot. The parking assistance method includes: generating a guide route from the boarding-alighting area to the parking area that is a target position when an entering instruction for the autonomous vehicle to park is input while the autonomous vehicle is located in the boarding-alighting area; extracting a route map from previously prepared parking lot map information including position information of a passage of the parking lot, the boarding-alighting area, and the parking area and providing the route map to the autonomous vehicle, the route map being indicative of a portion of the parking lot map information regarding the guide route; and providing the guide route to the autonomous vehicle; and providing the autonomous vehicle with a near-side map indicative of a portion of the parking lot map information from a near-side region set in advance to the boarding-alighting area when the autonomous vehicle is located in the near-side region and before the entering instruction is input and the autonomous vehicle arrives at the boarding-alighting area. 
     A fourth aspect of the present disclosure is a non-transitory computer readable medium storing a parking assistance program executed by a computer mounted in a parking assistance device that is configured to assist in automatic valet parking of a vehicle. The vehicle is an autonomous vehicle configured to perform autonomous driving between a boarding-alighting area and a parking area in a parking lot. The parking assistance program includes instructions, when executed by the computer, causing the computer to: generate a guide route from the boarding-alighting area to the parking area that is a target position when an entering instruction for the autonomous vehicle to park is input while the autonomous vehicle is located in the boarding-alighting area; extract a route map from previously prepared parking lot map information including position information of a passage of the parking lot, the boarding-alighting area, and the parking area, the route map being indicative of a portion of the parking lot map information regarding the guide route; provide the route map to the autonomous vehicle; provide the guide route to the autonomous vehicle; and provide the autonomous vehicle with a near-side map indicative of a portion of the parking lot map information from a near-side region set in advance to the boarding-alighting area when the autonomous vehicle is located in the near-side region and before the entering instruction is input and the autonomous vehicle arrives at the boarding-alighting area. 
     According to such a configuration, the management device transmits only the route map related to the guide route in the parking lot map information to the autonomous vehicle, and thus the autonomous vehicle does not need to store all of the parking lot map information. Therefore, when the parking lot map information is stored in the autonomous vehicle, it is possible to restrict the capacity of the memory of the autonomous vehicle from becoming tight. 
     1. Embodiment 
     [1-1. Configuration of Parking Assistance System  1 ] 
     A configuration of a parking assistance system  1  will be described with reference to  FIGS.  1  to  3   . As illustrated in  FIG.  1   , the parking assistance system  1  includes a vehicle entering section  3  set as an alighting area where a user gets off, and a vehicle exiting section  5  set as a boarding area where the user gets on, a parking area  7 , and a rotary  9 . Hereinafter, a region including the vehicle entering section  3 , the vehicle exiting section  5 , the parking area  7 , and the rotary  9  will also be referred to as the parking lot. The vehicle entering section  3  and the vehicle exiting section  5  will be collectively referred to as boarding-alighting areas  3  and  5 . 
     The parking lot and the outside of the parking lot are separated by an entrance gate  15 G disposed at an entrance  15  and an exit gate  27 G disposed at an exit  27 . An entrance road  14 A and an exit road  14 B are respectively connected to the outside of the entrance  15  and the outside of the exit  27 . 
     An autonomous vehicle  18  that uses the parking lot travels along the entrance road  14 A and approaches the entrance  15  with manual driving that is driving by a user. Before the autonomous vehicle  18  arrives at the entrance  15 , the autonomous vehicle  18  enters from an impossible region  1 B where communication with the management device  39  of the parking assistance system  1  is impossible into a possible region  1 A where communication with the management device  39  is possible. The inside of the parking lot is set to the possible region  1 A. In  FIG.  1   , a boundary between the impossible region  1 B and the possible region  1 A is illustrated only around the entrance  15 , but the possible region  1 A is set to include the entire parking lot. In the present embodiment, the region from the entrance road  14 A to the entrance  15  is described as a region where the vehicle moves with manual driving, but the vehicle may move with autonomous driving. 
     When the autonomous vehicle  18  enters the possible region  1 A, the management device  39  and the autonomous vehicle  18  start communication before the autonomous vehicle  18  arrives at the entrance gate  15 G. When this communication is started, the management device  39  performs various determinations such as whether the autonomous vehicle  18  can be parked in the parking lot by using an automatic valet parking function. 
     As a result of various determinations, if parking is possible, the management device  39  opens the entrance gate  15 G and permits the autonomous vehicle  18  to enter the parking lot. The autonomous vehicle  18  enters the rotary  9  after passing through the entrance gate  15 G. The rotary  9  is a region that connects a parking region other than the parking area  7  of the parking lot, that is, the vehicle entering section  3 , the vehicle exiting section  5 , the entrance  15 , and the exit  27 , and is a region where the autonomous vehicle  18  can move freely without receiving instructions from the management device  39 . The autonomous vehicle  18  travels on the rotary  9  with manual driving. The possible region  1 A in the regarding outside the parking lot and the rotary  9  correspond to a near-side region in the present disclosure. 
     In the present embodiment, the rotary  9  is described as a region where the autonomous vehicle  18  moves with manual driving, but may move with autonomous driving. The vehicle entering section  3  and the vehicle exiting section  5  are each provided with multiple sections. The autonomous vehicle  18  moves to a section of the vehicle entering section  3  specified by the management device  39 . 
     The autonomous vehicle  18  has an automatic valet parking function. The automatic valet parking function includes a function of traveling from the vehicle entering section  3  to a parking position in the parking area  7  and parking and a function of traveling from the parking position in the parking area  7  to the vehicle exiting section  5  with autonomous driving. In other words, the autonomous vehicle  18  only needs to be able to perform the automatic valet parking function in the vehicle entering section  3 , the vehicle exiting section  5 , and the parking area  7 , and does not need to have the function of performing autonomous driving outside the parking lot and inside the rotary  9 . Alternatively, the autonomous vehicle  18  may have the function of performing autonomous driving outside the parking lot and inside the rotary  9 . 
     The automatic valet parking function includes particularly a function of repeatedly acquiring position information of the autonomous vehicle  18  and transmitting the position information to the management device  39  that is a parking assistance device of the present disclosure, and a function of receiving a guide route from the management device  39  and controlling the autonomous vehicle  18  to travel along the guide route. The position information of the autonomous vehicle  18  indicates an estimation result of the current location of the autonomous vehicle  18 , and includes, for example, coordinate values in a region of the parking lot. 
     The guide route includes position information of nodes that the autonomous vehicle  18  is required to pass through and markers that are detected when the autonomous vehicle  18  travels along the nodes. The marker is also called a landmark and is, for example, a two-dimensional barcode. The marker is disposed on a road surface or wall surface in the parking lot. The marker has, for example, a rectangular shape. The position information of the markers included in the guide route represents position information of four corners of the rectangular markers. The guide route may include information regarding a set speed when the autonomous vehicle  18  passes through the node. 
     The vehicle entering section  3  and the vehicle exiting section  5  are adjacent to an entrance  23  of a facility  22  such as a store. In the present embodiment, the vehicle entering section  3  and the vehicle exiting section  5  are disposed with the rotary  9  separated from the entrance  23 . An occupant of the autonomous vehicle  18  loaded into the vehicle entering section  3  can get off the autonomous vehicle  18  and proceed to the entrance  23  on foot. The occupant can proceed to the vehicle exiting section  5  from the entrance  23  of the facility  22  on foot. 
     The vehicle exiting section  5  is disposed closer to the exit  27  than the vehicle entering section  3 . The autonomous vehicle  18  can move from the vehicle exiting section  5  to the outside of the parking lot through the rotary  9  and the exit gate  27 G with manual driving by the user. The management device  39  opens the exit gate  27 G to the autonomous vehicle  18  for which the payment of a parking fee for the parking lot has been completed. After passing through the exit gate  27 G, the autonomous vehicle  18  can travel on the exit road  14 B and head for a destination. While traveling on the exit road  14 B, the autonomous vehicle  18  moves from the possible region  1 A where communication with the management device  39  is possible to the impossible region  1 B where communication is impossible. 
     The parking area  7  is a place in which multiple autonomous vehicles  18  can be parked. Multiple sections are provided in the parking area  7 . Each section provided in the vehicle entering section  3 , the vehicle exiting section  5 , and the parking area  7  is a region in which one autonomous vehicle  18  can be parked. The autonomous vehicle  18  can travel from the vehicle entering section  3  to the parking area  7 . The autonomous vehicle  18  can travel from the parking area  7  to the vehicle exiting section  5 . 
     As illustrated in  FIG.  2   , the parking assistance system  1  includes the management device  39 , an infrastructure  41 , and a terminal device  43 . The management device  39  includes a control unit  47  and a communication unit  49 . The control unit  47  includes a microcomputer including a CPU  51  and, for example, a semiconductor memory (hereinafter referred to as a memory  53 ) such as a RAM or a ROM. The management device  39  can manage multiple autonomous vehicles  18 . 
     Each function of the control unit  47  is realized by the CPU  51  executing a program stored in a non-transitory tangible storage medium. The program includes a parking assistance program of the present disclosure. In this example, the memory  53  corresponds to a non-transitory tangible storage medium storing the program. A method corresponding to the program is executed by executing the program. The control unit  47  may include one microcomputer or multiple microcomputers. 
     The control unit  47  has a configuration for transmitting, to the autonomous vehicle  18 , a guide route to a target position such as a parking position in the parking area  7 , an exiting position, map information of the parking lot, a parking start instruction, and an exiting start instruction. For example, as illustrated in  FIG.  3   , the control unit  47  includes a route generation unit  47 A, a first map provision unit  47 B, a route provision unit  47 C, a second map provision unit  47 D, and a communication establishment unit  47 E. An operation of each of the units  47 A to  47 E forming the control unit  47  will be described later. The first map provision unit  47 B of the present embodiment corresponds to a first provision unit of the present disclosure, and the second map provision unit  47 D of the present embodiment corresponds to a second provision unit of the present disclosure. 
     The memory  53  stores parking lot map information that is map information of the parking lot. The parking lot map information also includes information representing a state of a section in the parking area  7 . As the state of the section, there are an empty state (hereinafter referred to as an empty state) and a state occupied by the autonomous vehicle  18  (hereinafter referred to as an occupied state). The communication unit  49  can perform communication with the autonomous vehicle  18 . 
     In addition to the above information, the map information includes, for example, position information of a parking frame, position information of a node, a link, and an obstacle in the parking lot, position information of a marker, and information indicating a travel boundary referred to when the autonomous vehicle  18  estimates its own position. 
     The infrastructure  41  has a function of acquiring information (hereinafter referred to as in-parking lot information) representing an internal situation of the parking assistance system  1  and providing the in-parking lot information to the management device  39 . The infrastructure  41  includes a camera, a lidar, and the like that capture images of the inside of the parking lot. 
     Examples of the in-parking lot information include information representing a position of an obstacle, information representing a state of a section in the parking area  7 , and position information of the autonomous vehicle  18  present in the parking assistance system  1 . 
     As illustrated in  FIG.  1   , the terminal device  43  is installed in the vicinity of the vehicle entering section  3 . The terminal device  43  outputs a parking request signal in response to an input operation, for example, a parking request that is the intention of a user to load the autonomous vehicle  18 . The parking request signal is a signal for requesting that the autonomous vehicle  18  in the vehicle entering section  3  is transported to the parking area  7  and parked therein. When the terminal device  43  outputs a signal corresponding to the input operation to the management device  39 , the terminal device  43  outputs identification information and the like of the autonomous vehicle  18 . 
     The terminal device  43  outputs an exiting request signal in response to an input operation, for example, an exiting request that is the intention of the user to unload the autonomous vehicle  18 . The exiting request signal is a signal for requesting that the autonomous vehicle  18  parked in the parking area  7  is guided to the vehicle exiting section  5 . 
     The terminal device  43  outputs identification information of the autonomous vehicle  18  in response to an input operation, for example. The identification information is, for example, information such as a number plate for uniquely specifying the autonomous vehicle  18 . 
     The terminal device  43  may be configured as a mobile terminal device such as a smart phone owned by the user, for example. Hereinafter, the parking request and the exiting request will be collectively referred to as a movement request, and the parking request signal and the exiting request signal will be collectively referred to as a movement request signal. 
     As described above, the autonomous vehicle  18  has an automatic valet parking function. As illustrated in  FIG.  2   , the autonomous vehicle  18  includes a control unit  69 , a sensor group  71 , a position information acquisition unit  73 , and a communication unit  75 . 
     The control unit  69  includes a microcomputer including a CPU  691  and, for example, a semiconductor memory (hereinafter referred to as a memory  692 ) such as a RAM or a ROM. The control unit  69  controls each unit of the autonomous vehicle  18 . The control unit  69  performs control for realizing the autonomous driving function. Functions executed by the control unit  69  include functions as a storage unit and a deletion unit in the present disclosure. These functions will be described later. 
     The autonomous vehicle  18  acquires the map information of the parking lot and the guide route from the management device  39 , and uses the map information of the parking lot and the guide route when autonomous driving is performed. 
     The sensor group  71  acquires peripheral information representing a peripheral situation of the autonomous vehicle  18 . Examples of details of the peripheral information include a position of an obstacle present around the autonomous vehicle  18 . The sensor group  71  includes, for example, a camera and a lidar. The autonomous vehicle  18  uses the peripheral information when performing autonomous driving. 
     The position information acquisition unit  73  acquires the position information of the autonomous vehicle  18 . The position information acquisition unit  73  is, for example, a position estimation system based on a lidar and map information. The autonomous vehicle  18  uses the position information when performing autonomous driving. The communication unit  75  can perform communication with the management device  39 . 
     [1-2. Process] 
     [1-2-1. Movement Management Process Executed by Management Device  39 ] 
     A movement management process executed by the management device  39  will be described with reference to  FIG.  4   . The movement management process is, for example, a process that is started when the management device  39  is powered on, and then repeatedly executed. The processes after step (hereinafter referred to as “S”)  2  in the present process are executed for each autonomous vehicle  18  that has requested movement. Hereinafter, a process executed by the control unit  47  (particularly the CPU  51 ) of the management device  39  will also be referred to as a process executed by the management device  39 . 
     The management device  39  determines whether a movement request signal has been received in S 1  of the movement management process illustrated in  FIG.  4   . If the movement request signal has been received, the process proceeds to S 12 . If the movement request signal has not been received, the process proceeds to S 2 . 
     When a user such as an occupant of the autonomous vehicle  18  inputs a movement request corresponding to a parking request of the present disclosure by operating the terminal device  43  after getting off the vehicle, the terminal device  43  transmits a movement request signal corresponding to this input to the management device  39 . In this case, the user inputs vehicle information such as a number plate for specifying the vehicle, user information such as a user ID and a password for specifying the user, and other necessary types of information, to the terminal device  43 . 
     When the terminal device  43  is operated, unique information such as an identification ID for specifying the terminal device  43 , the vehicle information, and the user information is transmitted to the management device  39 . After performing operation for the movement request, the user can leave the parking lot and head for a destination such as the facility  22 . 
     Subsequently, in S 2 , the communication establishment unit  47 E of the management device  39  determines whether the autonomous vehicle  18  that is performing communication is a new communication vehicle that is about to be parked, that is, whether the vehicle has entered the possible region  1 A where communication is possible from the impossible region  1 B where communication is impossible. The communication establishment unit  47 E is configured to establish communication with the autonomous vehicle  18  that has entered the possible region  1 A. 
     When it is determined in S 2  that the vehicle is not a new communication vehicle, the process returns to  51 . When it is determined in S 2  that the vehicle is a new communication vehicle, in S 3  the second map provision unit  47 D of the management device  39  extracts a near-side map from the memory  53  and provides the near-side map to the autonomous vehicle  18 . The near-side map will also be referred to as near-side map information. The process in S 3  is performed before a entering intention such as a parking request is input and before the autonomous vehicle  18  arrives at the boarding-alighting areas  3  and  5 . The entering intention is an example of a entering instruction. 
     The near-side map is part of the parking lot map information, and is map information regarding a region including the entire rotary  9  (for example, a region  31  illustrated in  FIG.  1   ). In the present embodiment, the second map provision unit  47 D extracts data corresponding to the near-side map from the parking lot map information in which the entire parking lot is collected as one piece of data. However, as the parking lot map information, the near-side map and a map of other portions (for example, multiple divided maps or map information of the parking area  7 ) may be separated in advance as separate data and stored in the memory  53 . In this case, the second map provision unit  47 D may extract the near-side map separated in advance. 
     The memory  53  may store the near-side map information and multiple pieces of divided map information. Alternatively, the memory  53  may store the near-side map information and map information corresponding to the parking area  7 . When the memory  53  stores the map information corresponding to the parking area  7 , the first map provision unit  47 B extracts or creates multiple divided maps corresponding to the parking area  7  from the map information based on the guide route set for the autonomous vehicle  18 . 
     The parking lot map information includes positions of a passage of the parking lot, the boarding-alighting areas  3  and  5 , and the parking area  7 , and the passage includes information such as nodes and links commonly used in navigation maps. The parking lot map information may include at least a node indicating the position of the passage. By referring to the parking lot map, the autonomous vehicle  18  can recognize positions of passages, obstacles, parking frames, and the like on the map. 
     However, the near-side map is not map information of the entire parking lot, but map information of the rotary  9 . The near-side map includes information such as positions of the boarding-alighting areas  3  and  5 , positions of the gates  15 G and  27 G, and positions of travelable regions in the rotary  9 . 
     The autonomous vehicle  18  that has received the parking lot map information such as the near-side map is configured to store the parking lot map information in the memory  692 . 
     Subsequently, in S 4 , the management device  39  determines whether the autonomous vehicle  18  has arrived at the entrance gate  15 G. The management device  39  may perform the determination by using the position information transmitted from the autonomous vehicle  18 , the camera provided at the entrance gate  15 G, and the like. The management device  39  receives position information of the autonomous vehicle  18  transmitted from the autonomous vehicle  18  in S 42  that will be described later. 
     When it is determined in S 4  that the autonomous vehicle  18  has not arrived at the entrance gate  15 G, the present process repeats S 4 . When it is determined in S 4  that the autonomous vehicle  18  has arrived at the entrance gate  15 G, in S 5 , the second map provision unit  47 D continues to transmit the near-side map. 
     The process in S 5  may be omitted if the transmission of the near-side map is completed before the autonomous vehicle  18  arrives at the entrance gate  15 G. The transmission of the near-side map in S 3  may be omitted, and, in this case, the near-side map may be transmitted in S 5 . 
     Subsequently, in S 11 , the management device  39  determines whether a movement request signal has been received. When the movement request signal has not been received, the present process repeats S 11 . When the movement request signal has been received, the process proceeds to S 12 . The user parks the autonomous vehicle  18  in the boarding-alighting areas  3  and  5 , gets off the vehicle, and then operates the terminal device  43  to input a movement request. 
     Subsequently, the management device  39  transmits an AVP mode command in S 12 . The AVP mode command is a command for switching a driving mode of the autonomous vehicle  18  from manual driving by the user to autonomous driving by the control unit  69  of the autonomous vehicle  18 . When the autonomous vehicle  18  receives the AVP mode command, the autonomous vehicle  18  makes necessary preparations for autonomous driving, such as activating cameras and sensors necessary for the autonomous driving in the sensor group  71 . 
     Subsequently, the management device  39  receives the position information transmitted from the autonomous vehicle  18  in S 13 . The management device  39  performs a movement setting process in S 14 . The movement setting process is a process of generating a guide route and moving the autonomous vehicle  18  to a target position along this guide route. When the movement setting process is ended, the management device  39  ends the movement management process. 
     [1-2-2. Movement Setting Process] 
     A movement setting process executed by the management device  39  will be described with reference to  FIG.  5   . In the movement setting process, first, in S 21 , the management device  39  of the management device  39  selects a target position, here a parking position or an exiting position. 
     As the parking position, an empty section (vehicle chamber) in the parking area  7  is selected. As the exiting position, an empty section in the vehicle exiting section  5  is selected. For example, the management device  39  determines a state of each section as follows. When the autonomous vehicle  18  is parked in a certain section, the autonomous vehicle  18  sends identification information of the section and parking start information to the management device  39 . When the autonomous vehicle  18  leaves the section in which the autonomous vehicle  18  has been parked until then, the autonomous vehicle  18  sends the identification information of the section and parking end information to the management device  39 . 
     The management device  39  determines a state of each section based on the history of information sent from the autonomous vehicle  18 . The management device  39  may also determine a state of each partition based on information provided by the infrastructure  41 . 
     When there is only one empty section, the management device  39  selects that section as a parking position. When there are multiple empty sections, the management device  39  selects one of the multiple empty sections as a parking position based on a predetermined criterion. As the criteria, for example, there is a criteria of selecting a section closest to the vehicle entering section  3 , a criterion of selecting a section closest to the vehicle exiting section  5 , or a criterion of selecting a section in an area where empty sections are gathered. 
     Subsequently, in S 22 , the route generation unit  47 A of the management device  39  sets a guide route by using the parking lot map information. The management device  39  sets a guide route for the autonomous vehicle  18  to autonomously travel, the guide route being a route from the current location of the autonomous vehicle  18  to the parking position selected in S 21 . 
     Subsequently, the first map provision unit  47 B sends map information of a first portion  32 A out of the parking lot map information to the autonomous vehicle  18 . The first map provision unit  47 B first extracts a route map (also referred to as partial map information) representing a portion related to the guide route from the parking lot map information. 
     The portion related to the guide route represents a range within which target objects such as obstacles, markers, and lane lines can be sensed by sensors such as a camera and a sonar of the autonomous vehicle  18 . In addition to the passage in the parking area  7 , the position of each section of the boarding-alighting areas  3  and  5 , and the position of each section of the parking area  7 , the route map includes position information of target objects including obstacles, markers, and lane lines that can be sensed by the sensors of the autonomous vehicle  18 . The sensors of the autonomous vehicle  18  include sensors that detect a relative distance between the autonomous vehicle  18  and an object around the autonomous vehicle  18 . 
     In the example illustrated in  FIG.  1   , the route map indicates map information within a range including all ranges indicated by the first portion  32 A, a second portion  32 B, and a third portion  32 C. The first map provision unit  47 B does not transmit the entire parking lot map information to the autonomous vehicle  18 , but transmits a route map that is at least a part of the parking lot map information and includes the guide route and the sensible range. 
     Although the management device  39  may transmit the route map without any change, the guide route is divided into multiple routes at predetermined distances to form multiple divided routes. The parking lot map information of the portion related to the divided route is extracted as multiple divided maps obtained by dividing the route map. In the example illustrated in  FIG.  1   , map information of each of the first portion  32 A, the second portion  32 B, and the third portion  32 C corresponds to a respective one of the multiple divided maps. In the example illustrated in  FIG.  1   , the multiple divided maps are drawn to partially overlap each other, but the multiple portions may be in contact with each other. 
     The management device  39  may store an order of providing the multiple divided maps to the autonomous vehicle  18  along the guide route from the current location of the autonomous vehicle  18  to the selected parking position, and update position information that will be described later. 
     The first map provision unit  47 B provides the autonomous vehicle  18  with the multiple divided maps in descending order of distance from a target position in accordance with movement of the autonomous vehicle  18 . The first map provision unit  47 B transmits only map information of the first portion  32 A. 
     Subsequently, in S 24 , the route provision unit  47 C of the management device  39  uses the communication unit  49  to transmit information representing the guide route set in S 22  (hereinafter referred to as guide route information). As will be described later, the autonomous vehicle  18  and other vehicles that are autonomous vehicles  18  other than the autonomous vehicle  18  receive the guide route information and start autonomous driving along the guide route. 
     Subsequently, in S 25 , the management device  39  determines whether a reroute request has been received. The reroute request is a request transmitted from another vehicle or from the inside of the management device  39 , for example, when the other vehicle stops on the route due to trouble or when the guide route for the autonomous vehicle  18  cannot be used. 
     When a reroute request has not been received in S 25 , the management device  39  acquires the position information of the autonomous vehicle  18  in S 26 . Subsequently, in S 27 , the management device  39  determines whether the autonomous vehicle  18  has arrived at the update position. The update position is a position set in each of the portions excluding the third portion  32 C that is the last portion among the first portion  32 A, the second portion  32 B, and the third portion  32 C, and is a position serving as a trigger to provide map information of the next portion. The last portion indicates a divided map that is provided to the autonomous vehicle  18  last among the first portion  32 A, second portion  32 B, and third portion  32 C. 
     When it is determined in S 27  that the autonomous vehicle  18  has arrived at the update position, the management device  39  transmits the map information of the next portion to the autonomous vehicle  18  in S 28 . The next portion is a portion farthest from the target position among portions that have not been transmitted. 
     For example, if the map information of the first portion  32 A and the second portion  32 B has already been transmitted, the third portion  32 C corresponds to the next portion. In this case, the map information of the third portion  32 C is transmitted. On the other hand, when the autonomous vehicle  18  has not arrived at the update position in S 27 , or when S 28  has been performed, the process proceeds to S 39 . 
     An example in which the first map provision unit  47 B provides a route map or a divided map illustrating the parts related to the guide route will be described. 
       FIGS.  8 A,  8 B,  8 C, and  8 D  illustrate parking lot map information related to guide routes. As illustrated in  FIG.  8 A , when the route generation unit  47 A generates the guide route from the current location and the target position of the autonomous vehicle  18 , the first map provision unit  47 B extracts a region related to the guide route from the parking lot map information, and generates partial map information. The region related to the extracted guide route is within a range in which target objects such as obstacles, markers, and lane lines can be sensed by the sensors such as a camera and a sonar of the autonomous vehicle  18 . 
     As described above, the management device  39  may transmit the route map without any change, or may create multiple divided route maps. When the route map is divided into multiple routes, the route map may be divided based on a predetermined distance, or may be divided based on a data capacity (file size) of the route map. For example, when a data capacity of the partial map information is less than a predetermined reference value, the entire route map as illustrated in  FIG.  8 A  is transmitted to the autonomous vehicle  18  without dividing the partial map information. 
     On the other hand, when the data size of the partial map information is greater than the predetermined reference value, the partial map information is divided such that the data size of one divided map is smaller than the reference value, such as divided maps  32 D,  32 E, and  32 F illustrated in  FIGS.  8 B to  8 D . The predetermined reference value is, for example, a file size of map information that can be stored by the autonomous vehicle  18  or a size of the in-vehicle memory of the autonomous vehicle  18 . In this case, the management device  39  transmits the divided maps  32 D,  32 E, and  32 F to the autonomous vehicle  18  in the order of the divided maps  32 D,  32 E, and  32 F as the autonomous vehicle  18  moves toward the target position. 
     By the way, when it is determined in S 25  that a reroute request has been received, the process proceeds to S 30 . The management device  39  transmits a stop command to the autonomous vehicle  18  in S 30 . That is, when receiving the reroute request, the management device  39  transmits the stop command to the autonomous vehicle  18  before setting a new target position. In this case, the management device  39  transmits the stop command without determining a traveling state of the autonomous vehicle  18 . The autonomous vehicle  18  stops the autonomous vehicle  18  immediately after receiving the stop command. 
     However, the management device  39  may transmit the stop command only when necessary, such as when a traveling direction changes. In this case, after the guide route is set in S 36  that will be described later, the stop command may be transmitted as necessary. When the stop command is not sent, it is preferable to send a reroute command to reroute. 
     Subsequently, in S 31 , the management device  39  receives the position information. The present process is similar to S 26 . Subsequently, in S 32 , the management device  39  selects a target position. The present process is similar to S 21 , and may be omitted when the target position is not changed. 
     Subsequently, in S 36 , the route generation unit  47 A sets a guide route. The present process is similar to S 22 . Subsequently, in S 37 , the parking lot map information is transmitted. The parking lot map information transmitted here is parking lot map information related to the guide route after the rerouting, and may be a part of divided parking lot map information. Subsequently, in S 38 , the management device  39  provides the guide route. The present process is similar to S 24 . 
     Subsequently, in S 39 , the management device  39  determines whether the communication unit  49  has received a movement completion notification. The movement completion notification is a notification transmitted by the autonomous vehicle  18  when the autonomous vehicle  18  is parked at the target position. When the parking completion notification has been received, the present process is ended. When the parking completion notification has not been received, the process returns to S 25 . 
     [1-2-3. Automatic Parking Process] 
     An automatic parking process executed by the autonomous vehicle  18  will be described with reference to  FIG.  6   . The automatic parking process is a process that is started when communication with the management device  39  is established, and the autonomous vehicle  18  performs autonomous driving according to the movement management process executed by the management device  39 . Hereinafter, a process executed by the control unit  69  (particularly the CPU  691 ) of the autonomous vehicle  18  will also be referred to as a process executed by the autonomous vehicle  18 . 
     First, in S 40 , the autonomous vehicle  18  determines whether the communication unit  75  has received map information of the parking lot. The map information here is near-side map information. When the map information has been received, the autonomous vehicle  18  estimates the current location of the autonomous vehicle  18  in S 41 . Subsequently, in S 42 , the autonomous vehicle  18  transmits the estimation result of the current location to the management device  39  as position information of the autonomous vehicle  18 . 
     Subsequently, in S 43 , the autonomous vehicle  18  displays any information such as the acquired parking lot map information on a display of the vehicle. Subsequently, the autonomous vehicle  18  determines whether the autonomous vehicle  18  has arrived at the entrance gate  15 G. The arrival at the entrance gate  15 G can be recognized by the autonomous vehicle  18  through a notification from the management device  39 , image processing by the camera of the autonomous vehicle  18 , or the like. 
     When the autonomous vehicle  18  has not arrived at the entrance gate  15 G, the process returns to S 41 . When the autonomous vehicle  18  has arrived at the entrance gate  15 G, the process proceeds to S 45 . 
     By the way, when the autonomous vehicle  18  has not received the map information in S 40 , the autonomous vehicle  18  proceeds to S 45  and determines whether an AVP mode command has been received. When the AVP mode command has not been received, the process returns to S 40 . 
     When the AVP mode command has been received, the autonomous vehicle  18  transitions to an AVP mode and performs the processes in and after S 46 . That is, the autonomous vehicle  18  estimates the current location of the autonomous vehicle  18  in S 46 . In S 47 , the autonomous vehicle  18  transmits the estimation result of the current location to the management device  39  as position information of the autonomous vehicle  18 . 
     Subsequently, the autonomous vehicle  18  determines in S 48  whether parking lot map information has been received. The parking lot map information here is map information of any one of the divided first portion  32 A, second portion  32 B, and third portion  32 C related to the guide route. 
     When the parking lot map information has not been received, the autonomous vehicle  18  repeats S 48 , and when the map information has been received, the autonomous vehicle  18  determines in S 49  whether guide route information has been received. The received map information is updated in the process in S 62  that will be described later. The guide route information is information transmitted by the management device  39 . In S 49 , when the guide route information has not been received, the present process repeats S 49 . 
     In S 46 , when the guide route information has been received, the autonomous vehicle  18  starts autonomous driving of the autonomous vehicle  18  in S 52 . When the autonomous vehicle  18  performs autonomous driving, the autonomous vehicle  18  travels in accordance with the guide route included in the guide route information. In this case, the autonomous vehicle  18  compares positions of a passage, an obstacle, a section, and the like indicated by the map information with positions of a passage, an obstacle, a section, and the like recognized by the autonomous vehicle  18 , and correctly recognizes a position of the autonomous vehicle  18 . 
     Subsequently, the autonomous vehicle  18  determines in S 53  whether the autonomous vehicle  18  has received a stop command or a reroute command. The stop command or the reroute command is transmitted by the management device  39 . When the stop command or the reroute command has been received, the process proceeds to S 54 , and when the stop command has been received, the autonomous vehicle  18  stops the autonomous vehicle  18 . S 54  is omitted when the reroute command has been received. Including the case where S 54  is omitted, the present process returns to S 48  after the process in S 54 . 
     In S 53 , when the autonomous vehicle  18  has not received the stop command or the reroute command, the autonomous vehicle  18  continues to perform autonomous driving in S 55 . In this case, the autonomous vehicle  18  repeatedly transmits the position information of the autonomous vehicle  18  to the management device  39  until it is determined in S 57  that will be described later that parking has been completed. The transmitted position information is received by the management device  39 . 
     Subsequently, in S 56 , the autonomous vehicle  18  deletes the map information of the traveled route. The function of S 56  corresponds to a deletion unit in the present disclosure. The map information of the traveled route represents map information related to the guide route that the autonomous vehicle  18  has already traveled, in the parking lot map information stored in the autonomous vehicle  18 . For example, when the autonomous vehicle  18  stores only the map information of the first portion  32 A, and the autonomous vehicle  18  has passed through half of the section indicated by the first portion  32 A, map information of the half from the memory  692  is deleted. 
     Alternatively, when the autonomous vehicle  18  stores the map information of the first portion  32 A and the second portion  32 B, and the autonomous vehicle  18  has passed through the section indicated by the first portion  32 A, the map information of the first portion  32 A is deleted from the memory  692 . 
     Subsequently, the autonomous vehicle  18  determines whether the movement has been completed in S 57 . Completion of the movement means that the autonomous vehicle  18  arrives at the target position set in the management device  39 . When the movement has not been completed, the process returns to S 53 . 
     When the movement has been completed, the process proceeds to S 58 , the autonomous vehicle  18  uses the communication unit  75  to transmit a movement completion notification, and ends the present process. The management device  39  receives the transmitted movement completion notification. 
     [1-2-4. Map Information Update Process] 
     A map information update process executed by the autonomous vehicle  18  will be described with reference to  FIG.  7   . The map information update process is a process that is repeatedly executed when the autonomous vehicle  18  is powered on. 
     In the map information update process, first, in S 61 , the autonomous vehicle  18  determines whether parking lot map information has been received. The parking lot map information here is a divided map such as a near-side map or map information of the first portion  32 A. 
     When the parking lot map information has not been received in S 61 , the present process is ended. When the parking lot map information has been received in S 61 , the autonomous vehicle  18  stores the parking lot map information in the memory  692  in S 62 . The function of S 62  corresponds to a storage unit in the present disclosure. In this case, in addition to the parking lot map information already stored in the memory  692 , the received new parking lot map information is stored in the memory  692 . However, when rerouting is performed, the parking lot map information already stored in the memory  692  may be deleted. 
     [1-3. Advantageous Effects] 
     According to the first embodiment described in detail above, the following effects are achieved. 
     (1a) One aspect of the present disclosure is the parking assistance system  1  configured to assist in automatic valet parking of a vehicle, and includes the autonomous vehicle  18 , the management device  39 , and the terminal device  43 . The autonomous vehicle  18  is configured to perform autonomous driving between the boarding-alighting areas  3  and  5  in the parking lot and a parking position. The management device  39  is configured to manage entering and exiting of the autonomous vehicle  18  in the parking lot. The terminal device  43  is configured to be operable by a user. 
     The management device  39  includes the route generation unit  47 A, the first map provision unit  47 B, and the route provision unit  47 C. When the intention to load the autonomous vehicle  18  is input from the terminal device  43  while the autonomous vehicle  18  is located in the boarding-alighting areas  3  and  5 , the route generation unit  47 A is configured to generate a guide route from the boarding-alighting areas  3  and  5  to the parking position that is a target position. 
     The first map provision unit  47 B is configured to extract a route map representing parking lot map information of a portion related to the guide route from the previously prepared parking lot map information including positions of a passage of the parking lot, the boarding-alighting areas  3  and  5 , and the parking position and provide the route map to the autonomous vehicle  18 . The route provision unit  47 C is configured to provide the guide route to the autonomous vehicle  18 . 
     According to such a configuration, the management device  39  transmits only the route map related to the guide route out of the parking lot map information to the autonomous vehicle  18 , and thus the autonomous vehicle  18  does not need to store all of the parking lot map information. Therefore, when the parking lot map information is stored in the autonomous vehicle  18 , it is possible to restrict a capacity of the memory  692  of the autonomous vehicle  18  from becoming tight. 
     (1b) In one aspect of the present disclosure, the first map provision unit  47 B is configured to use multiple divided guide routes as multiple divided routes, extract parking lot map information of portions related to the divided routes as multiple divided maps obtained by dividing the route map, and provide the autonomous vehicle  18  with the multiple divided maps in descending order of distance from the target position in accordance with movement of the autonomous vehicle  18 . 
     According to such a configuration, since the divided maps, which are divided parking lot map information, are sequentially provided in accordance with movement of the autonomous vehicle  18 , a capacity of the parking lot map information to be stored in the autonomous vehicle  18  can be further reduced. Therefore, it is possible to further restrict the tightness of the memory capacity of the autonomous vehicle  18 . 
     (1c) In one aspect of the present disclosure, the second map provision unit  47 D is configured to extract a near-side map representing parking lot map information of a portion from a near-side region to the boarding-alighting areas  3  and  5  from the parking lot map information when the autonomous vehicle  18  is located in the near-side region set in advance before the entering intention is input and before the autonomous vehicle  18  arrives at the boarding-alighting areas  3  and  5 , and provide the near-side map to the autonomous vehicle  18 . 
     According to such a configuration, the management device  39  transmits the near-side map before the autonomous vehicle  18  arrives at the boarding-alighting areas  3  and  5 , and can thus perform any other processes before the autonomous vehicle  18  arrives at the boarding-alighting areas  3  and  5 . For example, the management device  39  can perform any check process as a process using the near-side map in a near-side region such as the entrance gate  15 G. More specifically, an operation check for autonomous driving during manual driving, checking of a self-position estimation and accuracy check, checking of tilting of a camera or a sensor, checking of hardware or an application, and the like can be performed. 
     (1d) In one aspect of the present disclosure, the autonomous vehicle  18  is configured to pass through the entrance gate  15 G that separates the inside and the outside of the parking lot from the outside of the parking lot and head for the boarding-alighting areas  3  and  5  with manual driving by a user. The communication establishment unit  47 E of the management device  39  is configured to establish communication in a near-side region set outside the gate. The second map provision unit  47 D is configured to extract a near-side map and provide the near-side map to the autonomous vehicle  18  when communication is established. 
     According to such a configuration, since the management device  39  starts to transmit the near-side map when communication with the autonomous vehicle  18  is established, the processing waiting time at the entrance gate  15 G can be reduced when there is a procedure such as checking to be completed at the entrance gate  15 G. 
     (1e) In one aspect of the present disclosure, the autonomous vehicle  18  is configured to store the route map in the memory  692  upon receiving the route map from management device  39 . The autonomous vehicle  18  is configured to delete, from the memory  692 , a portion in the route map in which the autonomous vehicle  18  has finished traveling. 
     According to such a configuration, since the autonomous vehicle  18  deletes, from the memory, the portion in the route map in which the autonomous vehicle  18  has finished traveling, it is possible to further reduce a capacity of the memory  692  of the autonomous vehicle  18  from becoming tight. 
     (1f) In one aspect of the present disclosure, when the route generation unit  47 A is configured to generate a new guide route from the current location of the autonomous vehicle  18  to a changed target position upon receiving a reroute command for changing the guide route. The first map provision unit  47 B is configured to extract parking lot map information of a portion related to the new guide route as a route map, and provide the route map to the autonomous vehicle  18 . 
     According to such a configuration, even when the guide route is rerouted, the management device  39  transmits the route map related to the new guide route to the autonomous vehicle  18 , and thus it is possible to provide the necessary and sufficient route map to the autonomous vehicle  18 . 
     (1g) In one aspect of the present disclosure, each of the multiple divided maps provided by the first map provision unit  47 B, excluding the divided map to be provided last to the autonomous vehicle  18 , is configured to include update positions. A guide route divided into multiple routes is defined as multiple divided routes, and parking lot map information of portions related to the divided routes is defined as multiple divided maps obtained by dividing the route map. 
     The first map provision unit  47 B is configured to provide the multiple divided maps to the autonomous vehicle  18  in descending order of distance from the target position in accordance with movement of the autonomous vehicle  18 . The first map provision unit  47 B is configured to determine whether the autonomous vehicle  18  has reached the update position, and provide the next divided map when it is determined that the autonomous vehicle  18  has reached the update position. 
     According to such a configuration, since the next divided map is provided every time the autonomous vehicle  18  arrives at the update position in the divided map, it is possible to restrict a large number of divided maps from being transmitted to the autonomous vehicle  18 . Therefore, it is possible to restrict the memory capacity of the autonomous vehicle  18  from becoming tight. 
     (1h) In one aspect of the present disclosure, the management device  39  is configured to acquire information regarding a magnitude of a capacity of the memory of the autonomous vehicle  18  from the autonomous vehicle  18  when communication with the autonomous vehicle  18  is established. 
     According to such a configuration, the memory capacity of the autonomous vehicle  18  is sent to the management device  39 . Therefore, the management device  39  can provide the parking lot map information after recognizing the memory capacity of the autonomous vehicle  18 . 
     (1i) In one aspect of the present disclosure, the route map includes position information of a passage of the parking lot, the boarding-alighting areas  3  and  5 , and the parking area  7 , and position information of a target object including at least any of an obstacle, a marker, and a lane line that can be sensed by sensors of the autonomous vehicle  18 . 
     According to such a configuration, since the route map includes the position information of the target object that can be sensed by the sensors of the autonomous vehicle  18 , the management device  39  can compare the position information of the target object sensed by the autonomous vehicle  18  with the position information of the target object in the route map. Therefore, the management device  39  can recognize a position of the autonomous vehicle  18  with higher accuracy. 
     2. Other Embodiments 
     Although the embodiment of the present disclosure has been described above, the present disclosure is not limited to the above embodiment, and can be realized in various modifications. 
     (2a) In the above embodiment, the management device  39  divides the parking lot map information regarding the guide route and provides the divided map information to the autonomous vehicle  18 , but the present disclosure is not limited to this. For example, the management device  39  may transmit the parking lot map information related to the guide route as one piece of map information (referred to as partial map information) without dividing the parking lot map information. 
     (2b-1) In the above embodiment, the management device  39  transmits a divided map obtained by dividing the route map each time the autonomous vehicle  18  travels a predetermined distance along the guide route, the present disclosure is not limited to this. For example, the management device  39  may transmit a divided map each time the autonomous vehicle  18  travels for a predetermined period of time. A magnitude of a data capacity of the divided map, for example, the number of divisions of the route map may be determined according to a magnitude of a capacity of the memory  692  of the autonomous vehicle  18 . The divided map may be transmitted earlier as a communication speed becomes lower. 
     The management device  39  may acquire information region the magnitude of the capacity of the memory  692  when communication with the autonomous vehicle  18  is established. The management device  39  preferably has a function of recognizing the speed of communication with the autonomous vehicle  18 . Alternatively, the management device  39  may acquire information regarding a file size of map information that can be stored by the autonomous vehicle  18 . 
     (2b-2) That is, in one aspect of the present disclosure, the management device  39  may be configured to acquire information regarding the file size of the route map that can be stored in the autonomous vehicle  18  from the autonomous vehicle  18 . 
     According to such a configuration, the file size of the route map that can be stored in the autonomous vehicle  18  is sent to the management device  39 . Therefore, the management device  39  can provide the parking lot map information after recognizing the file size of the route map that can be stored in the autonomous vehicle  18 . Although a timing at which the management device  39  acquires the file size information is freely selected, the management device  39  is preferably configured to acquire the file size information before providing the route map to the autonomous vehicle  18 . 
     (2c) In the above embodiment, the route map transmitted by the management device  39  to the autonomous vehicle  18  is map information of the parking lot along the set guide route, but the present disclosure is not limited to this. For example, the management device  39  may divide and store the parking lot map information in advance, and extract divided map information to include the guide route. 
       FIGS.  9 A,  9 B, and  9 C  illustrate parking lot map information related to a guide route. As illustrated in  FIG.  9 A , for example, the management device  39  divides the parking lot map of the parking lot into six areas  7 A,  7 B,  7 C,  7 D,  7 E, and  7 F and stores the divided areas. After setting the guide route for the autonomous vehicle  18 , the management device  39  extracts divided maps for the areas  7 A and  7 B that are divided maps including the guide route as illustrated in  FIGS.  9 B and  9 C . 
     The divided map for the area  7 A illustrated in  FIG.  9 B  corresponds to a first portion, and the divided map for the area  7 B illustrated in  FIG.  9 C  corresponds to a second portion. The management device  39  transmits the divided map for the area  7 A and then transmits the divided map for the area  7 B to the autonomous vehicle  18 . 
     When the map information can be transmitted as one file by calculating a file size of the map information corresponding to the guide route, it is not necessary to divide the map information into multiple files. Map information obtained by combining the map information for the area  7 A with the map information for the area  7 B may be transmitted to the autonomous vehicle  18 . 
     (2d) The control unit  47  and the method thereof described in the present disclosure may be implemented by a dedicated computer that is provided by configuring a processor and memory programmed to execute one or more functions embodied by a computer program. Alternatively, the control unit  47  and the method thereof described in the present disclosure may be realized by a dedicated computer provided by including a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit  47  and the method thereof described in the present disclosure may be realized by one or more dedicated computers configured by a combination of a processor and a memory programmed to execute one or multiple functions and a processor configured by one or more hardware logic circuits. The computer programs may also be stored in a computer readable non-transitory tangible recording medium as computer executable instructions. A method for realizing the functions of each unit included in the control unit  47  does not necessarily include software, and all the functions may be realized by using one or multiple pieces of hardware. 
     (2e) The multiple functions of one constituent element in the above embodiments may be realized by multiple constituent elements, or a function of one constituent element may be realized by multiple constituent elements. Multiple functions of multiple constituent elements may be realized by one constituent element, or one function realized by multiple constituent elements may be realized by one constituent element. A part of the configuration of the above embodiment may be omitted. At least a part of the configuration of the above embodiment may be added to or substituted for the configuration of the other embodiment. 
     (2f) In addition to the parking assistance system  1  described above, the present disclosure can be implemented in various forms, for example, a device such as the management device  39  having the parking assistance system  1  as a constituent element or the autonomous vehicle  18 , a program for causing a computer to function as the device, a non-transitory tangible storage medium such as a semiconductor memory recording the program, and a parking assistance method.