Position estimation system, position estimation method, and position estimation program

Abstract

A position estimation system (10) according to the present invention comprises a client terminal (40) and an estimation server (20) that estimates the position and orientation of the client terminal (40) in a global coordinate system. The client terminal (40) includes: a client unit (42) that acquires an estimated value (Ps) from the estimation server (20) and calculates the position and orientation (Pn) of the client terminal (40); a display unit (45) that displays an object, and suspends update of the object display or releases the suspension of update through user operation; a calculation unit (43) that calculates a relative movement amount (Mpq) of the client terminal (40) from the suspension of update to the release of the suspension of update; and a correction unit (44) that corrects the position and orientation of the client terminal (40) using the relative movement amount (Mpq) as a correction value.

Description

Position estimation system, position estimation method, and position estimation program

[0001] The present invention relates to a position estimation system, a position estimation method, and a position estimation program.

[0002] There are self-localization technologies that estimate the three-dimensional position and orientation of devices, robots, and mobility. Self-localization technologies include methods that use images and methods that use LiDAR. For example, in image-based self-localization, image features are first extracted from multiple images of a space, and three-dimensional information of the image features (hereinafter referred to as feature space) is calculated by performing three-dimensional reconstruction. Next, image features are also extracted from a query image of the space, and the shooting position and orientation of the query image are estimated by comparing them with the feature space.

[0003] Masahiko Tsuji, Takahiro Matsumoto, Taiga Yoshida, and Yutaka Chiaki, "Proposal of a self-location estimation method using images with a camera and 3D-LiDAR," 26th Image Recognition and Understanding Symposium

[0004] For example, if the amount of texture is small, the image features will also be small. Therefore, if there is little texture in the space, it is not possible to extract a sufficient amount of image features, which leads to a problem of large estimation errors in the shooting position and orientation of the query image.

[0005] The present invention has been made in light of the above circumstances, and an object of the present invention is to provide a position estimation system, a position estimation method, and a position estimation program that are capable of performing position estimation with a small estimation error.

[0006] One aspect of the present invention is a position estimation system. The position estimation system includes a client terminal and an estimation server that estimates the position and orientation of the client terminal in a global coordinate system. The client terminal includes a client unit that acquires estimates from the estimation server and calculates the position and orientation of the client terminal, a display unit that displays an object and pauses or cancels updating of the display of the object in response to a user operation, a calculation unit that calculates the amount of relative movement of the client terminal from the time the update pause is stopped until the time the update pause is canceled, and a correction unit that corrects the position and orientation of the client terminal using the amount of relative movement as a correction value.

[0007] One aspect of the present invention is a position estimation method that includes the steps of calculating a position and orientation of a client terminal in a global coordinate system, displaying an object, pausing and releasing the update stop of the display of the object in response to a user operation, calculating a relative movement amount of the client terminal between the time the update stop is released and the time the update stop is released, and correcting the position and orientation of the client terminal using the relative movement amount as a correction value.

[0008] One aspect of the present invention is a location estimation program that causes a computer to execute at least some of the functions of the components of the location estimation system described above.

[0009] According to the present invention, there are provided a position estimation system, a position estimation method, and a position estimation program that can perform position estimation with a small estimation error.

[0010] FIG. 1 is a block diagram showing the functional configuration of a position estimation system according to an embodiment. FIG. 2 is a flowchart of the first half showing the flow of an example of operation of the position estimation system according to an embodiment. FIG. 3 is a flowchart of the second half showing the flow of an example of operation of the position estimation system according to an embodiment. FIG. 4 is a diagram showing a time series flow of an example of operation of the position estimation system according to an embodiment. FIG. 5 is a diagram showing the movement of a client terminal from a measurement time to a current time. FIG. 6 is a diagram showing the movement of a client terminal and an object from an update stop time to an update stop release time. FIG. 7 is a block diagram showing an example of the hardware configuration of a computer constituting each of a self-location estimation server, an AR object display position adjustment server, and a client terminal according to an embodiment.

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] (Functional Configuration) First, the functional configuration of a position estimation system 10 according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a block diagram showing the functional configuration of a position estimation system 10 according to an embodiment.

[0013] The position estimation system 10 includes a self-position estimation server 20 , an AR object display position adjustment server 30 , and a client terminal 40 .

[0014] Hereinafter, the coordinate system of the self-location estimation server 20 will be referred to as the "global coordinate system," and the coordinate system of the client terminal 40 will be referred to as the "local coordinate system." The self-location estimation server 20 has already generated a feature space of the space and can estimate the position using an image. The self-location estimation server 20 estimates the position and orientation in the global coordinate system (feature space).

[0015] The self-location estimation server 20 includes a self-location estimation unit 21 and a feature space DB (database) 22 .

[0016] The self-location estimation unit 21 receives a request for self-location estimation including an image from the client terminal 40, references the feature space DB 22 that has information on the three-dimensional feature space, and estimates the position and orientation in the global coordinate system in which the image was captured. The self-location estimation unit 21 returns the estimation result to the client terminal 40 as a request response.

[0017] The AR object display position adjustment server 30 includes a feature amount space display unit 31 and an AR object display position adjustment unit 32 .

[0018] The feature space display unit 31 displays a three-dimensional feature space based on information in the feature space DB 22 of the self-location estimation server 20. The information in the feature space DB 22 is imported into the AR object display position adjustment server 30 from the self-location estimation server 20 via a network, for example. Alternatively, the information in the feature space DB 22 may be imported into the AR object display position adjustment server 30 by storing a storage device that replicates the feature space DB 22 in the AR object display position adjustment server 30.

[0019] The three-dimensional feature space is displayed, for example, by converting the three-dimensional positions of image features stored in the feature space DB 22 into a point cloud file and displaying it. The point cloud file only needs to contain information on xyz coordinate positions, and may be, for example, a file such as ply, e57, or las. RGB information may also be added to the point cloud file.

[0020] The AR object display position adjustment unit 32 places the AR object in the three-dimensional feature amount space. The AR object display position adjustment unit 32 also transmits the position and orientation Pa of the placed AR object to the client terminal 40.

[0021] The client terminal 40 includes a sensor 41 , a self-position estimation client unit 42 , a relative movement amount calculation unit 43 , an error correction unit 44 , and an AR object display unit 45 .

[0022] The sensor 41 is a device that measures a space. For example, the sensor 41 is a camera or LiDAR. The sensor 41 measures a space and records measurement data and measurement time Ts. The measurement data is, for example, an image captured by a camera or a point cloud measured by LiDAR.

[0023] The self-location estimation client unit 42 requests self-location estimation from the self-location estimation server 20. The self-location estimation client unit 42 transmits the measurement data measured by the sensor 41 and the measurement time Ts together with the request for self-location estimation to the self-location estimation server 20. Thereafter, the self-location estimation client unit 42 obtains, as a request response, the position and attitude estimate value Ps of the client terminal 40 in the global coordinate system, which is the estimation result of the self-location estimation server 20.

[0024] The relative movement amount calculation unit 43 calculates the relative movement amount of the client terminal 40 in the local coordinate system. The relative movement amount calculation unit 43 is, for example, an inertial measurement unit (IMU). For example, the relative movement amount calculation unit 43 calculates the relative movement amount Mxy of the client terminal 40 in the local coordinate system from an arbitrary time Tx to a time Ty.

[0025] The self-position estimation client unit 42 also acquires, for example, a relative movement amount Msn from the measurement time Ts to the time Tn from the relative movement amount calculation unit 43. The self-position estimation client unit 42 also adds the relative movement amount Msn to information on the measured position / attitude estimated value Ps in the global coordinate system, calculates the position / attitude Pn of the client terminal 40 in the global coordinate system at the time Tn, and transmits it to the error correction unit 44.

[0026] The AR object display unit 45 has a display device such as a touch panel display, etc. The AR object display unit 45 displays the AR object based on the position and orientation Pa of the AR object in the global coordinate system acquired from the AR object display position adjustment unit 32 of the AR object display position adjustment server 30 and the position and orientation Pn of the client terminal 40 in the global coordinate system at time Tn acquired from the error correction unit 44.

[0027] The AR object display unit 45 stops updating and releases the update stop of the display of the AR object in response to a user operation. The user operation may be, for example, a touch operation on the touch panel display or a gesture operation on the sensor 41 (camera or LiDAR). The AR object display unit 45 receives an instruction from the user to stop updating and release the update stop by detecting the touch operation or recognizing the gesture operation.

[0028] The AR object display unit 45 records the update stop time Tp and the update stop release time Tq of the display of the AR object. The AR object display unit 45 transmits the recorded update stop time Tp and update stop release time Tq to the error correction unit 44. When the update stop of the display of the AR object is released, the AR object display unit 45 resumes updating the display of the AR object, and the AR object is displayed at the original position and orientation Pa in the global coordinate system.

[0029] The error correction unit 44 acquires the position and orientation Pn of the client terminal 40 in the global coordinate system at time Tn from the self-position estimation client unit 42. The error correction unit 44 acquires the update stop time Tp and the update stop release time Tq of the display of the AR object from the AR object display unit 45, and acquires the relative movement amount Mpq of the client terminal 40 between the update stop time Tp and the update stop release time Tq from the relative movement amount calculation unit 43. The error correction unit 44 adds the relative movement amount Mpq to the position and orientation Pn of the client terminal 40 in the global coordinate system at time Tn as a position and orientation correction value, and calculates a corrected position and orientation P'n of the client terminal 40 in the global coordinate system.

[0030] (Operation Example) Next, an operation example of the position estimation system 10 according to the embodiment will be described with reference to Fig. 2, Fig. 3, and Fig. 4. Fig. 2 and Fig. 3 are flowcharts showing the flow of the operation example of the position estimation system 10 according to the embodiment. Fig. 4 is a diagram showing the time series flow of the operation example shown in Fig. 2 and Fig. 3.

[0031] 2 and 3 and the time series flow shown in Fig. 4 show the processing up to correcting the position and orientation of the client terminal 40 and initially displaying the object in the correct position and orientation at the initial stage of operation of the position estimation system 10. After that, the position estimation system 10 uses the corrected position and orientation of the client terminal 40 to display the object in the correct position and orientation.

[0032] First, as a preparation stage, in step S1, the feature space display unit 31 displays a three-dimensional feature space based on the feature space DB 22 of the self-location estimation server 20. Furthermore, the AR object display position adjustment unit 32 places an AR object in the three-dimensional feature space, and adjusts the position and orientation Pa of the AR object in the global coordinate system.

[0033] In addition, in step S2, the AR object display unit 45 acquires the position and orientation Pa of the AR object in the global coordinate system from the AR object display position adjustment server 30.

[0034] Next, in order to display the AR object, in step S3, the sensor 41 measures the surrounding space, records the measurement data and the measurement time Ts, and transmits them to the self-location estimation client unit 42.

[0035] In step S4, the self-location estimation client unit 42 makes a request for self-location estimation to the self-location estimation server 20. The request for self-location estimation includes the measurement data acquired from the sensor 41 and the measurement time Ts.

[0036] In step S5, the self-position estimation unit 21 receives a request for self-position estimation from the self-position estimation client unit 42, estimates the position and attitude estimation value Ps of the client terminal 40 in the global coordinate system at the measurement time Ts from the measurement data, and transmits the position and attitude estimation value Ps to the self-position estimation client unit 42.

[0037] In step S6, the self-location estimation client unit 42 acquires the position and orientation estimate Ps of the client terminal 40 in the global coordinate system at the measurement time Ts, which is the estimation result, from the self-location estimation server 20.

[0038] In step S7, the self-position estimation client unit 42 requests the relative movement amount calculation unit 43 to calculate the relative movement amount Msn of the client terminal 40 in the local coordinate system from measurement time Ts to time Tn, and acquires the relative movement amount Msn.

[0039] In step S8, the self-position estimation client unit 42 adds the relative movement amount Msn in the local coordinate system from the measurement time Ts to the time Tn, which is acquired from the relative movement amount calculation unit 43, to the position / orientation estimated value Ps in the global coordinate system at the measurement time Ts, to calculate the position / orientation Pn of the client terminal 40 in the global coordinate system at the time Tn, and transmits this to the error correction unit 44. The error correction unit 44 also transmits the acquired position / orientation Pn of the client terminal 40 to the AR object display unit 45.

[0040] In step S9, the AR object display unit 45 displays the AR object based on the position and orientation Pa of the AR object in the global coordinate system obtained from the AR object display position adjustment server 30 in step S2 and the position and orientation Pn of the client terminal 40 in the global coordinate system at time Tn obtained from the error correction unit 44.

[0041] In step S10, the AR object display unit 45 stops updating the display of the AR object and releases the update stop in response to a user operation, and records the update stop time Tp and the update stop release time Tq. In more detail, the AR object display unit 45 temporarily stops updating the display of the AR object and then releases the update stop in order to move the client terminal 40 in order to correct a deviation in position and orientation between the client terminal 40 and the AR object, and records the update stop time Tp and the update stop release time Tq and transmits them to the error correction unit 44.

[0042] Therefore, the AR object display unit 45 displays information instructing the user to stop updating the display of the AR object, move the client terminal 40 so that the AR object is displayed at a predetermined position and attitude, and cancel the stop of updating the display of the AR object. Instructions to the user may be conveyed outside the system, such as in a manual, instead of being conveyed by the AR object display unit 45.

[0043] The user performs operations to stop updating the display of the AR object, move the client terminal 40 so that the AR object is displayed at a predetermined position and orientation, and release the update stop of the display of the AR object. The operations to stop updating and release the update stop of the display of the AR object may be, for example, a touch operation on the touch panel display or a gesture operation on the sensor 41. The AR object display unit 45 receives instructions from the user to stop updating and release the update stop by detecting the touch operation or recognizing the gesture operation.

[0044] When the AR object display unit 45 receives an instruction from a user to stop updating the display of the AR object, it stops updating the display of the AR object, records the update stop time Tp, and waits for the user to cancel the stop of updating the display of the AR object.

[0045] Thereafter, when the AR object display unit 45 receives an instruction to cancel the stop of updating the display of the AR object through a user operation, it cancels the stop of updating the display of the AR object and records the update stop cancellation time Tq.

[0046] In step S11, the error correction unit 44 requests the relative movement amount calculation unit 43 to calculate the relative movement amount Mpq of the client terminal 40 from the update stop time Tp to the update stop release time Tq. The relative movement amount calculation unit 43 calculates the relative movement amount Mpq between the position / orientation Pp of the client terminal 40 at the update stop time Tp and the position / orientation Pq of the client terminal 40 at the update stop release time Tq. The error correction unit 44 obtains the relative movement amount Mpq from the relative movement amount calculation unit 43.

[0047] In step S12, the error correction unit 44 adds the relative movement amount Mpq obtained from the relative movement amount calculation unit 43 in step S11 to the position and orientation Pn of the client terminal 40 in the global coordinate system at time Tn as a position and orientation correction value, calculates the corrected position and orientation P'n of the client terminal 40 in the global coordinate system at time Tm, and transmits it to the AR object display unit 45.

[0048] In step S13, the AR object display unit 45 displays the AR object based on the position and orientation Pa of the AR object in the global coordinate system obtained in step S2 and the corrected position and orientation P'n of the client terminal 40 in the global coordinate system at time Tm obtained from the error correction unit 44.

[0049] (Method for calculating position and orientation of client terminal 40 at time Tn) Next, a method for calculating the position and orientation of the client terminal 40 at time Tn will be described with reference to Fig. 5. As shown in Fig. 5, it is assumed that the client terminal 40 has relatively moved from the position and orientation estimated value Ps to the position and orientation Pn by a relative movement amount Msn between measurement time Ts and time Tn.

[0050] The estimated position and orientation value Ps of the client terminal 40 at the measurement time Ts is given by the following equation (1): The rotation angle representing the orientation is the Euler angle.

[0051]

[0052] The relative movement amount Msn of the client terminal 40 from the measurement time Ts to the time Tn is set as follows.

[0053]

[0054] At this time, the estimated position and orientation value Pn of the client terminal 40 at time Tn can be calculated according to the following formula.

[0055]

[0056] (Method for correcting position and orientation of client terminal 40 at time Tn) Next, a method for correcting position and orientation of client terminal 40 at time Tn will be described with reference to Fig. 6. As shown in Fig. 6, it is assumed that the client terminal 40 has relatively moved from position and orientation estimated value Pp to position and orientation Pq by a relative movement amount Mpq between update stop time Tp and update stop release time Tq of the AR object display.

[0057] The estimated position and orientation value Pn of the client terminal 40 at time Tn is set as follows: The rotation angle representing the orientation is set as Euler angles.

[0058]

[0059] The relative movement amount Mpq of the client terminal 40 from time Tp to time Tq is defined as follows:

[0060]

[0061] At this time, the corrected position and orientation P'n of the client terminal 40 can be calculated according to the following formula.

[0062]

[0063] In this way, when the AR object is moved by the relative movement amount Mpq, the AR object is displayed in its original position. In other words, the position and orientation of the client terminal 40 corrected by the relative movement amount Mpq is the correct position and orientation of the client terminal 40.

[0064] (Effect) According to the embodiment, even in a space with a small amount of texture, it is possible to estimate the position and orientation of the client terminal 40 with a small estimation error. Moreover, the estimation of the position and orientation of the client terminal 40 can be performed by a simple operation by the user without the need to install markers or the like in the space.

[0065] (Hardware Configuration) Next, a description will be given of the hardware configurations of the self-location estimation server 20, the AR object display position adjustment server 30, and the client terminal 40 of the position estimation system 10. For example, the self-location estimation server 20, the AR object display position adjustment server 30, and the client terminal 40 are each configured as a computer. Examples of computers include a personal computer, a server computer, a smartphone, an AR device, etc.

[0066] 7 is a block diagram showing an example of the hardware configuration of each of the self-location estimation server 20, the AR object display position adjustment server 30, and the client terminal 40 according to the embodiment, in other words, the hardware configuration of a computer 100 that constitutes each of the self-location estimation server 20, the AR object display position adjustment server 30, and the client terminal 40. The computer 100 has a control device 120, an input device 140, and an output device 150.

[0067] The control device 120 controls the entire computer 100. The control device 120 includes a processor 121, a read only memory (ROM) 122, a random access memory (RAM) 123, and an auxiliary storage device .

[0068] The processor 121, ROM 122, RAM 123, auxiliary storage device 124, input device 140, and output device 150 are electrically connected to one another via a bus 130, and can transmit and receive data.

[0069] The processor 121 is configured by a general-purpose hardware processor including, for example, a CPU (Central Processing Unit), a GPU (Graphical Processing Unit), etc. The processor 121 executes various functions of the computer 100 by executing programs deployed in the RAM 123.

[0070] The ROM 122 is a non-volatile memory that constitutes part of the main storage device. The ROM 122 non-temporarily stores a startup program required to start up the computer 100. The processor 121 loads the startup program in the ROM 122 into the RAM 123 and executes it to start up the computer 100. The ROM 122 is configured, for example, from an erasable programmable read-only memory (EPROM), and is capable of storing various startup settings in addition to the startup program.

[0071] The RAM 123 is a volatile memory that constitutes part of the main storage device. The RAM 123 temporarily stores programs required for processing by the processor 121 and data required for executing the programs. In other words, the RAM 123 functions as a work area for the processor 121.

[0072] The auxiliary storage device 124 is configured with non-volatile memory such as a hard disk drive (HDD) or a solid state drive (SSD). The auxiliary storage device 124 can non-temporarily store various programs executed by the processor 121 and data required to execute the programs. The processor 121 executes various functions of the computer 100 by loading the programs in the auxiliary storage device 124 into the RAM 123 and executing them.

[0073] The input device 140 is a device for a user to input information and instructions, and accepts input of information and instructions. The input device 140 includes a keyboard, a pointing device, etc. The pointing device includes a mouse, a trackpad, a touch screen, etc.

[0074] The output device 150 is a device that outputs information to provide information to a user. The output device 150 is, for example, a display device that displays characters, images, etc. on a screen. For example, the output device 150 is a liquid crystal display, an organic EL display, a plasma display, etc.

[0075] The output device 150 and the input device 140 may be configured as an input / output device having the functions of both. Such an input / output device may be configured as, for example, a touch panel display.

[0076] The input device 140 may also include a device that inputs information or data from an external device. For example, the input device 140 may include a wired or wireless interface or receiving device. The input device 140 may also include a sensor that measures space, such as a camera or LiDAR.

[0077] The output device 150 may also include a device that outputs information or data to the outside. For example, the output device 150 may include a wired or wireless interface or transmission device.

[0078] The input device 140 may also include a device that reads data from a computer-readable recording medium 160 that non-temporarily records data such as a program. For example, the recording medium 160 includes disks such as flexible disks, optical disks (CD-ROM, CD-R, DVD-ROM, DVD-R, etc.), magneto-optical disks (MO, etc.), semiconductor memories, etc. The input device 140 includes drives, readers, etc. for these.

[0079] The program stored in the auxiliary storage device 124 is provided to the computer 100, for example, via the recording medium 160. Alternatively, the program may be stored on a server on a network and provided to the computer 100 by downloading it.

[0080] For example, when the computer 100 starts up, the processor 121 executes a startup program in the ROM 122 to start up the operating system (OS). Under the control of the OS, the processor 121 monitors input instructions, connections to external devices, etc. Also, under the control of the OS, the processor 121 sets up a program area and a data area in the RAM 123.

[0081] In response to an instruction to start a program, processor 121 reads the program from auxiliary storage device 124 into the program area of ​​RAM 123, and also reads data necessary for executing the program from auxiliary storage device 124 into the data area of ​​RAM 123. Processor 121 calculates the data in the data area in accordance with the program and writes the calculation results into the data area.

[0082] Through these operations, the processor 121, RAM 123, and auxiliary storage device 124 work together to execute at least a portion of the functions of the control device 120. Furthermore, the control device 120, input device 140, and output device 150 work together to execute at least a portion of the functions of the computer 100.

[0083] The programs non-temporarily stored in the auxiliary storage device 124 include a program that causes the processor 121 to execute at least some of the functions of the control device 120. In other words, the processor 121 executes this program to execute at least some of the functions of the control device 120.

[0084] As a result, the control device 120 cooperates with the input device 140 and the output device 150 to execute at least part of the functions of the self-location estimation server 20 , the AR object display position adjustment server 30 , or the client terminal 40 .

[0085] (Other) Embodiments of the present invention have been described above with reference to the drawings. However, the above embodiment is merely an example of a configuration that embodies the present invention. In other words, it is clear that the present invention is not limited to the above embodiment. Therefore, additions, omissions, substitutions, and other modifications of components may be made within the scope of the technical concept of the present invention.

[0086] In short, the present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the embodiments may be implemented in appropriate combinations, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combining selected elements from the disclosed elements. For example, if the problem can be solved and the desired effect can be obtained even if some elements are deleted from all elements shown in the embodiments, the configuration from which these elements are deleted can be extracted as an invention.

[0087] 10... Position estimation system 20... Self-position estimation server 21... Self-position estimation unit 22... Feature space database 30... AR object display position adjustment server 31... Feature space display unit 32... AR object display position adjustment unit 40... Client terminal 41... Sensor 42... Self-position estimation client unit 43... Relative movement amount calculation unit 44... Error correction unit 45... AR object display unit 100... Computer 120... Control device 121... Processor 122... ROM 123... RAM 124... Auxiliary storage device 130... Bus 140... Input device 150... Output device 160... Recording medium

Claims

1. A position estimation system comprising: a client terminal; and an estimation server that estimates the position and orientation of the client terminal in a global coordinate system, wherein the client terminal comprises: a client unit that obtains estimated values ​​from the estimation server and calculates the position and orientation of the client terminal; a display unit that displays an object and stops and releases the update stop of the display of the object in response to a user operation; a calculation unit that calculates the amount of relative movement of the client terminal from the stop of the updating to the release of the updating stop; and a correction unit that corrects the position and orientation of the client terminal using the amount of relative movement as a correction value.

2. The position estimation system according to claim 1, wherein the display unit displays information instructing the user to stop updating the display of the object, move the client terminal, and release the stoppage of updating the display of the object in order to move the client terminal to correct a deviation in position and orientation between the client terminal and the object.

3. A position estimation method comprising the steps of: calculating the position and orientation of a client terminal in a global coordinate system; displaying an object; stopping and releasing the update stop of the display of the object in response to a user operation; calculating the amount of relative movement of the client terminal between the stopping of the update and the releasing of the update stop; and correcting the position and orientation of the client terminal using the amount of relative movement as a correction value.

4. A location estimation program that causes a computer to execute at least a portion of the functions of each component of the location estimation system according to claim 1.

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