A method and system for establishing an indoor absolute coordinate system

Abstract

The present invention provides a method and system for establishing an indoor absolute coordinate system, including starting to move from an initial position, and a combined measurement device carried during the movement to obtain observation data in real time; the combined measurement device includes a global navigation satellite system, a camera, a lidar, and an inertial measurement unit, and the observation data includes image data captured by the camera, point cloud data captured by the lidar, inertial data captured by the inertial measurement unit, and absolute coordinate data obtained by the global navigation satellite system outdoors; processing the observation data of adjacent frames to obtain the current coordinate calculation result, the calculation result including the absolute coordinates of a first target object in the indoor, the first target object being a positioning base station or a sensor, and further calculating the absolute coordinates of the second target object based on the absolute coordinates of the first target object in the indoor. The unified establishment of a high-precision and high-efficiency indoor and outdoor absolute coordinate system is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of indoor and outdoor positioning, and particularly to a method and system for establishing an indoor absolute coordinate system. Background Art

[0002] With the enrichment of human activity patterns and the improvement of mobile efficiency, indoor and outdoor positioning technologies have developed vigorously, demanding timeliness, accuracy, and unity of location information. GNSS positioning, ultrasonic positioning, WiFi positioning, UWB positioning, visual positioning, etc. are gradually moving towards multi-mode combined positioning, and the seamless switching of indoor and outdoor positioning tends to be integrated. Currently, in outdoor unobstructed areas, GNSS positioning technology can be used to achieve absolute positioning of targets; for indoor scenarios, only relative coordinates between an object and a positioning base station can be obtained. In particular, there is a need to unify indoor and outdoor coordinates into an absolute coordinate system in large stations, shopping malls, underground garages, industrial and mining sites, etc. At the same time, there are scenarios in the positioning field where multiple position sensing modules operate simultaneously to complete positioning tasks, and an accurate relative position relationship between various sensors needs to be established to unify the measurement results into an absolute coordinate system. For example, in multi-beam surveying in the marine surveying field, underwater acoustic systems, on-water GNSS positioning, attitude sensors, and other sensing modules need to operate synchronously to obtain accurate absolute coordinates of underwater terrain and features. As shown in Figure 1a-1 Figure b, expensive precision attitude sensors are basically installed at the geometric center position of the relatively safe ship cockpit plane, GNSS devices are installed on the top of the cockpit without signal obstruction, and underwater acoustic systems are basically installed at a certain side of the ship's hull. By measuring the positions of sensors distributed at different indoor and outdoor locations, an accurate relative position relationship is established to facilitate the conversion between synchronous measurement data of various sensors and unify them into the GNSS absolute coordinate system.

[0003] Currently, to unify the current indoor relative coordinate system to the outdoor absolute coordinate system, positioning devices such as total stations are used to introduce the absolute coordinate benchmark of outdoor reference points into the indoor area, and accurate absolute coordinates are assigned to indoor positioning base stations through total station measurements. This operation mode not only requires the production of a certain number of absolute coordinate reference points outdoors, but also requires additional measurement stations at corners and blocked areas to ensure line-of-sight between the total station and indoor positioning base stations, resulting in low operation efficiency. During the actual operation process, to quickly obtain the relative position relationship, operators will choose to directly measure the distance with a tape measure or a laser rangefinder, and directly make a right-angle horizontal or vertical turn at the corner. The right angle is also roughly estimated by the operator, resulting in low relative position measurement accuracy. Summary of the Invention

[0004] Based on the above problems, the present invention provides a [solution], aiming to solve the technical problems of low indoor positioning accuracy, low efficiency, and cumbersome measurement in the prior art.

[0005] A method for establishing an indoor absolute coordinate system includes two processes: pre-acquiring the absolute coordinates of at least one first target object in the indoor environment and acquiring the absolute coordinates of a second target object.

[0006] The process of pre-acquiring the absolute coordinates of the first target object in the indoor environment includes the following steps:

[0007] Step A1: Carry a combined measurement device, select a point that can directly obtain absolute coordinates through the Global Navigation Satellite System (GNSS) as the starting position, and start the combined measurement device at the starting position. The combined measurement device includes a GNSS, a camera, a lidar, and an Inertial Measurement Unit (IMU). The absolute coordinates of the starting position are directly obtained by the GNSS.

[0008] Step A2: Start moving from the starting position and use the combined measurement device carried during the movement to obtain observation data in real time. The observation data includes image data captured by the camera, point cloud data captured by the lidar, inertial data captured by the IMU, and absolute coordinate data that can be directly obtained by the GNSS during the movement.

[0009] Step A3: Process the observation data of adjacent frames to obtain the coordinate calculation result of the first target object identified in the current frame. The coordinate calculation result includes the absolute coordinates of the first target object in the indoor environment, where the first target object in the indoor environment includes positioning base stations and / or sensors.

[0010] Step A4: Select a point that can directly obtain absolute coordinates through the GNSS as the end position to end the movement. The absolute coordinates of the end position are directly obtained by the GNSS.

[0011] Step A5: Based on the observation data obtained during the movement from the starting position to the end position, perform loop detection to correct the coordinate calculation result of the first target object obtained during the movement to obtain a coordinate correction result.

[0012] Step A6: Save the absolute coordinates of the positioning base stations and / or sensors in the coordinate correction result.

[0013] The steps for obtaining the absolute coordinates of the second target object in the indoor environment include:

[0014] Step B1: Calculate the absolute coordinates of the second target object based on the saved absolute coordinates of the positioning base stations and / or sensors.

[0015] Furthermore, Step A2 includes:

[0016] Step A21: Perform feature matching on the image data of adjacent frames to obtain a matching result, and perform registration processing on the point cloud data of adjacent frames to obtain a registration result.

[0017] Step A22: Obtain the coordinate calculation result of the first target object in the current frame being recognized by combining the matching result, the registration result, the inertial data of the current frame, and the coordinate calculation result of the first target object in the previous frame.

[0018] Further, in step A22, it includes obtaining the optimized coordinate calculation result after being optimized by a filter.

[0019] Further, the first target object includes a positioning base station, and the second target object is a moving carrier;

[0020] Step B1: Calculate the absolute coordinate of the moving carrier based on the absolute coordinates of the positioning base stations in the indoor environment according to the principle of resection.

[0021] Further, there are at least 4 positioning base stations in the indoor environment.

[0022] Further, in step A3, some of the first target objects include positioning targets set at the positioning base stations. Process the observation data of adjacent frames to obtain the coordinate calculation result of the recognized positioning targets, and further process based on the coordinate calculation result of the positioning targets to obtain the absolute coordinates of the corresponding positioning base stations.

[0023] A system for establishing an indoor absolute coordinate system, including the aforementioned method for establishing an indoor absolute coordinate system, comprising:

[0024] A trigger module, configured to start the system in the selected first trigger mode and close the system in the selected second trigger mode;

[0025] A combinable measurement device that can be carried, connected to the trigger module, and is configured to obtain observation data in real time during the moving process after being started, and stop obtaining observation data when the system is closed;

[0026] The combinable measurement device includes a global navigation satellite system, a camera, a lidar, and an inertial measurement unit. The observation data includes image data captured by the camera, point cloud data captured by the lidar, inertial data captured by the inertial measurement unit, and the observation data further includes absolute coordinate data that can be directly obtained by the global navigation satellite system during the movement process;

[0027] Wherein, both the starting position and the ending position of the movement are selected as points where the global navigation satellite system can directly obtain absolute coordinates; the global navigation satellite system directly obtains the absolute coordinates of the starting position when starting and the coordinates of the ending position when closing;

[0028] The first processing module, connected to the combined measurement device, is used to process the observation data of adjacent frames based on known absolute coordinate data to obtain the coordinate calculation result of the first target object in the identified current frame, and the coordinate calculation result includes the absolute coordinates of the first target object indoors;

[0029] Among them, the first target object includes a positioning base station and / or a sensor;

[0030] The second processing module, connected to the first processing module, is used to perform loop detection based on the observation data obtained during the movement from the starting position to the ending position, and correct the coordinate calculation result of the first target object obtained during the movement to obtain a coordinate correction result;

[0031] The storage module, connected to the second processing module, is used to save the absolute coordinates of the positioning base station and / or the sensor in the coordinate correction result;

[0032] The third processing module, connected to the storage module, is used to calculate the absolute coordinates of the second target object based on the saved absolute coordinates of the positioning base station and / or the sensor.

[0033] Further, the first processing module includes:

[0034] The matching unit is used to perform feature matching on the image data of adjacent frames to obtain a matching result;

[0035] The registration unit, connected to the matching unit, is used to perform registration processing on the point cloud data of adjacent frames to obtain a registration result;

[0036] The calculation unit is respectively connected to the matching unit and the registration unit, and is used to combine the matching result, the registration result, the inertial data of the current frame, and the coordinate calculation result of the first target object in the previous frame to obtain the coordinate calculation result of the first target object in the identified current frame.

[0037] Further, the calculation unit also includes an optimized coordinate calculation result obtained by using a filter.

[0038] Further, the first target object includes a positioning base station, and the second target object is a moving carrier;

[0039] The third processing module is used to calculate the absolute coordinates of the moving carrier based on the absolute coordinates of the positioning base station indoors according to the principle of resection.

[0040] The beneficial technical effects of the present invention are as follows: The present invention uses SLAM technology to establish a high-precision indoor absolute coordinate system, improves the acquisition efficiency of the relative position relationship between indoors and outdoors, improves the relative position accuracy during indoor and outdoor multi-sensing, and meets the requirements of quickly and accurately unifying the indoor and outdoor positioning systems to the absolute coordinate system. Description of the Drawings

[0041] Figure 1a-1 Figure b is a schematic diagram of sensor settings for indoor positioning technology in the prior art;

[0042] Figure 1-2 Figure c is a flowchart of the steps of a method for establishing an indoor absolute coordinate system according to the present invention;

[0043] Figure 3-4 Figure d is a schematic diagram of modules of a system for establishing an indoor absolute coordinate system according to the present invention. Detailed implementation manners

[0044] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0045] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0046] Next, the present invention will be further described in conjunction with the accompanying drawings and specific embodiments, but it is not a limitation of the present invention.

[0047] Refer to Figure 1 , the present invention provides a method for establishing an indoor absolute coordinate system, including two processes of pre-obtaining the absolute coordinates of at least one first target object in the room and obtaining the absolute coordinates of a second target object;

[0048] The process of pre-obtaining the absolute coordinates of the first target object in the room includes the following steps:

[0049] Step A1, carry a combined measurement device, select a point that can directly obtain absolute coordinates through the global navigation satellite system as the starting position, start the combined measurement device at the starting position, the combined measurement device includes a global navigation satellite system, a camera, a lidar, and an inertial measurement unit, and the absolute coordinates of the starting position are directly obtained by the global navigation satellite system;

[0050] Step A2, start moving from the starting position, and use the combined measurement device carried during the movement to obtain observation data in real time; the observation data includes image data captured by the camera, point cloud data captured by the lidar, inertial data captured by the inertial measurement unit, and the observation data also includes absolute coordinate data that can be directly obtained by the global navigation satellite system during the movement;

[0051] Step A3: Process the observation data of adjacent frames to obtain the coordinate calculation result of the first target object in the currently recognized frame. The coordinate calculation result includes the absolute coordinates of the first target object indoors, where the first target object indoors includes a positioning base station and / or a sensor;

[0052] Step A4: Select a point whose absolute coordinates can be directly obtained through the Global Navigation Satellite System as the end position to end the movement. The absolute coordinates of the end position are directly obtained by the Global Navigation Satellite System;

[0053] Step A5: Based on the observation data obtained during the movement from the starting position to the end position, perform loop detection to correct the coordinate calculation result of the first target object obtained during the movement to obtain a coordinate correction result;

[0054] Step A6: Save the absolute coordinates of the positioning base station and / or sensor in the coordinate correction result;

[0055] The steps for obtaining the absolute coordinates of the second target object indoors include:

[0056] Step B1: Calculate the absolute coordinates of the second target object based on the saved absolute coordinates of the positioning base station and / or sensor.

[0057] Specifically, during the movement from the starting position in Step A2 to the end position in Step A4, the observation data also includes absolute coordinate data that can be obtained by the Global Navigation Satellite System.

[0058] Specifically, since the Global Navigation Satellite System cannot penetrate buildings indoors, it is impossible to perform positioning indoors, and absolute coordinates obtained by the Global Navigation Satellite System cannot be obtained indoors. Therefore, the absolute coordinate data obtained by the Global Navigation Satellite System belongs to the outdoor part. Before entering the indoor area from the starting position and after exiting the indoor area to the end position, that is, outdoors, the Global Navigation Satellite System always obtains absolute coordinates. That is, the observation data includes absolute coordinate data obtained by the Global Navigation Satellite System outdoors.

[0059] Specifically, in Step A3, according to the absolute coordinate data obtained by the Global Navigation Satellite System outdoors, process the observation data of adjacent frames to obtain the coordinate calculation result of the first target object in the currently recognized frame. The coordinate calculation result includes the absolute coordinates of the first target object indoors, where the first target object indoors includes a positioning base station and / or a sensor;

[0060] In step A3, the coordinate calculation result further includes the absolute coordinates of the first target object identified outdoors. Outdoors, the first target object outdoors is continuously identified based on the image data and the point cloud data, and the coordinate calculation result of the first target object outdoors is obtained by combining the absolute coordinate data obtained outdoors, the inertial data, and the observation data of the previous frame. Indoors, when there is no absolute coordinate data obtained by the global navigation satellite system, the first target object outdoors is continuously identified based on the image data and the point cloud data, and the coordinate calculation result of the first target object indoors is obtained by combining the inertial data and the observation data of the previous frame. As long as there is absolute coordinate data that can be directly obtained by the global navigation satellite system during the movement process, the absolute coordinate data is introduced into the coordinate calculation, making the absolute coordinates of the positioning base station and / or the sensor more accurate and the recognition algorithm more optimized.

[0061] Specifically, in step A5, the observation data used for loop detection includes the image data captured by the camera, the point cloud data captured by the lidar, the inertial data captured by the inertial measurement unit, and the absolute coordinate data that can be obtained by the global navigation satellite system, so as to correct the coordinate calculation result of the first target object to obtain a coordinate correction result.

[0062] The present invention uses the SLAM technology to establish a high-precision indoor absolute coordinate system. The SLAM technology is a new real-time positioning and mapping technology, mainly applied to the autonomous positioning during the movement of the robot. The combined positioning device developed based on the SLAM technology integrates sensors such as a GNSS positioning terminal, an inertial measurement unit (IMU), a panoramic high-definition camera, and a lidar. The absolute coordinate measurement accuracy reaches the centimeter level continuously within a short path with serious GNSS signal occlusion. The application of this technology can quickly and accurately obtain the relative position relationship between indoors and outdoors.

[0063] In the present invention, high-definition image data during the movement process is obtained through the panoramic camera, three-dimensional point cloud data is collected in real time by the lidar, external absolute coordinates are obtained by the GNSS device, and attitude change data during the movement process is obtained by the IMU. The initial position can be outdoors, and the absolute coordinates are directly obtained by the GNSS. The end position of the movement can also be outdoors, and the absolute coordinates are directly obtained by the GNSS. The starting position of the movement requires the GNSS positioning to be a fixed solution, and the unlocking time during the movement process should not exceed 150m, and the speed of the turning points during the movement process should be kept slow.

[0064] Before starting the measurement, move along an "8" - shaped path to calibrate the accuracy of the IMU.

[0065] See Figure 2 For further details, step A2 includes:

[0066] Step A21: Perform feature matching on the image data of adjacent frames to obtain a matching result, and perform registration processing on the point cloud data of adjacent frames to obtain a registration result;

[0067] Step A22: Combine the matching result, the registration result, the inertial data of the current frame, and the coordinate calculation result of the first target object in the previous frame to obtain the coordinate calculation result of the first target object in the identified current frame.

[0068] Further, in Step A22, it includes obtaining an optimized coordinate calculation result after being optimized by a filter.

[0069] Further, the first target object includes a positioning base station, and the second target object is a mobile carrier;

[0070] Step B1: Based on the absolute coordinates of the positioning base stations in the room, calculate the absolute coordinates of the mobile carrier based on the principle of forward intersection.

[0071] Further, there are at least 4 positioning base stations in the room.

[0072] Further, in Step A3, some of the first target objects include positioning targets set at the positioning base stations. Process the observation data of adjacent frames to obtain the coordinate calculation result of the identified positioning target, and further process based on the coordinate calculation result of the positioning target to obtain the absolute coordinates of the corresponding positioning base station.

[0073] The front-end program processes the image data and 3D point cloud data based on adjacent frames, performs reduction in combination with the synchronized IMU inertial data, and calculates the current coordinate calculation result in combination with the previous calculation result. The back-end program performs filter graph optimization processing on the coordinate calculation result and calculates the optimal absolute coordinate value to minimize the cumulative error during the movement process.

[0074] See Figure 3 The present invention also provides a system for establishing an indoor absolute coordinate system, including the foregoing method for establishing an indoor absolute coordinate system, including:

[0075] A trigger module (1), used to start the system in the selected first trigger mode and close the system in the selected second trigger mode;

[0076] A combinable measurement device (2) that can be carried, connected to the trigger module (1), used to obtain observation data in real time during movement after being carried when the system is started, and stop obtaining observation data when the system is closed;

[0077] The combined measurement device includes a global navigation satellite system, a camera, a lidar, and an inertial measurement unit. The observation data includes image data captured by the camera, point cloud data captured by the lidar, and inertial data captured by the inertial measurement unit. The observation data also includes absolute coordinate data that can be directly obtained by the global navigation satellite system during the movement process.

[0078] Among them, both the starting position and the ending position of the movement are selected as points where the global navigation satellite system can directly obtain absolute coordinates. The global navigation satellite system directly obtains the absolute coordinates of the starting position when starting up and directly obtains the coordinates of the ending position when shutting down.

[0079] The first processing module (3), connected to the combined measurement device (2), is used to process the observation data of adjacent frames to obtain the coordinate calculation result of the first target object identified in the current frame. The coordinate calculation result includes the absolute coordinates of the first target object indoors.

[0080] Among them, the first target object includes a positioning base station and / or a sensor.

[0081] The second processing module (4), connected to the first processing module (3), is used to perform loop detection based on the observation data obtained during the movement from the starting position to the ending position, and correct the coordinate calculation result of the first target object obtained during the movement to obtain a coordinate correction result.

[0082] The storage module (5), connected to the second processing module (4), is used to save the absolute coordinates of the positioning base station and / or the sensor in the coordinate correction result.

[0083] The third processing module (6), connected to the storage module (5), is used to calculate the absolute coordinates of the second target object based on the saved absolute coordinates of the positioning base station and / or the sensor.

[0084] See Figure 4 , further, the first processing module (3) includes:

[0085] The matching unit (31) is used to perform feature matching on the image data of adjacent frames to obtain a matching result.

[0086] The registration unit (32), connected to the matching unit (31), is used to perform registration processing on the point cloud data of adjacent frames to obtain a registration result.

[0087] The calculation unit (33), respectively connected to the matching unit (31) and the registration unit (32), is used to combine the matching result, the registration result, the inertial data of the current frame, and the coordinate calculation result of the first target object in the previous frame to obtain the coordinate calculation result of the first target object identified in the current frame.

[0088] Further, the calculation unit (33) further includes an optimized coordinate calculation result obtained by optimizing using a filter.

[0089] Further, the first target object includes a positioning base station, and the second target object is a mobile carrier;

[0090] The third processing module (6) is configured to calculate the absolute coordinates of the mobile carrier based on the absolute coordinates of the positioning base stations in the room and based on the principle of resection.

[0091] A method and system for establishing an indoor absolute coordinate system provided by the present invention, in a specific application scenario, for example, in order to achieve full coverage of indoor positioning signals, the positions of the base stations often appear in corners; when multiple sensors operate synchronously, to ensure measurement accuracy, special equipment needs to be placed in special positions, and direct visibility between internal and external devices generally cannot be guaranteed.

[0092] In this method and system, positioning targets are installed at indoor base stations and other sensors, and the absolute coordinates of the positioning targets are picked up through the method and system of the present invention. Further, the absolute coordinates of the indoor base stations and other sensors are obtained, and the indoor and outdoor positioning is unified to the absolute coordinate system. The absolute coordinate information of a large number of positioning base stations, other sensors, and even hidden base stations or hidden sensors in a certain distribution area can be obtained at one time, avoiding the cumbersome process of station-by-station measurement like a total station, and improving the efficiency of introducing the outdoor positioning reference into the indoor positioning reference. When the mobile terminal receives signals from 4 or more base stations with known absolute coordinates, the absolute coordinates of the mobile terminal can be obtained according to the principle of resection. In addition, according to the absolute coordinates between any two of the positioning base stations and other sensors, the relative coordinates between any two can be obtained.

[0093] The above are only preferred embodiments of the present invention, and do not limit the implementation manners and protection scope of the present invention accordingly. For those skilled in the art, it should be able to realize that all equivalent replacements and obvious changes made by using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for establishing an indoor absolute coordinate system, characterized in that, it includes two processes: pre-obtaining the absolute coordinates of at least one first target object in the indoor and obtaining the absolute coordinates of a second target object; The process of pre-obtaining the absolute coordinates of the first target object in the indoor includes the following steps: Step A1, carry a combined measurement device, select a point that can directly obtain absolute coordinates through the Global Navigation Satellite System as the starting position, start the combined measurement device at the starting position, the combined measurement device includes the Global Navigation Satellite System, a camera, a lidar, and an inertial measurement unit, and the absolute coordinates of the starting position are directly obtained by the Global Navigation Satellite System; Step A2, start moving from the starting position, and use the combined measurement device carried during the movement to obtain observation data in real time; the observation data includes image data captured by the camera, point cloud data captured by the lidar, inertial data captured by the inertial measurement unit, and the observation data also includes absolute coordinate data that can be directly obtained by the Global Navigation Satellite System during the movement; Step A3, process the observation data of adjacent frames to obtain the coordinate calculation result of the first target object identified in the current frame, and the coordinate calculation result includes the absolute coordinates of the first target object in the indoor, where the first target object in the indoor includes a positioning base station and / or a sensor; Step A4, select a point that can directly obtain absolute coordinates through the Global Navigation Satellite System as the end position to end the movement, and the absolute coordinates of the end position are directly obtained by the Global Navigation Satellite System; Step A5, based on the observation data obtained during the movement from the starting position to the end position, perform loop detection to correct the coordinate calculation result of the first target object obtained during the movement to obtain a coordinate correction result; Step A6, save the absolute coordinates of the positioning base station and / or the sensor in the coordinate correction result; The steps for obtaining the absolute coordinates of the second target object in the indoor include: Step B1, calculate the absolute coordinates of the second target object based on the saved absolute coordinates of the positioning base station and / or the sensor; The said Step A2 includes: Step A21, perform feature matching on the image data of adjacent frames to obtain a matching result, and perform registration processing on the point cloud data of adjacent frames to obtain a registration result; Step A22, combine the matching result, the registration result, the inertial data of the current frame, and the coordinate calculation result of the first target object in the previous frame to obtain the coordinate calculation result of the first target object identified in the current frame; The first target object includes a positioning base station, and the second target object is a mobile carrier; In the said Step B1, based on the absolute coordinates of the positioning base station in the indoor, calculate the absolute coordinates of the mobile carrier based on the principle of forward intersection; The indoor includes at least 4 said positioning base stations.

2. The method for establishing an indoor absolute coordinate system according to claim 1, characterized in that, In the step A22, it includes obtaining the optimized coordinate calculation result after filter optimization.

3. A method for establishing an indoor absolute coordinate system as described in claim 1, characterized in that, in the step A3, some of the first target objects include positioning targets set at the positioning base stations, and the observation data of adjacent frames is processed to obtain the coordinate calculation result of the identified positioning targets, and further, the absolute coordinates of the corresponding positioning base stations are obtained based on the coordinate calculation result of the positioning targets.

4. A system for establishing an indoor absolute coordinate system, characterized in that, it includes a method for establishing an indoor absolute coordinate system as described in any one of claims 1-3, including: a trigger module, configured to start the system in the first trigger mode and close the system in the second trigger mode; a portable combined measurement device, connected to the trigger module, configured to obtain observation data in real time during movement after being carried after startup, and stop obtaining observation data when the system is closed; the combined measurement device includes a global navigation satellite system, a camera, a lidar, and an inertial measurement unit, the observation data includes image data captured by the camera, point cloud data captured by the lidar, inertial data captured by the inertial measurement unit, and the observation data further includes absolute coordinate data that can be directly obtained by the global navigation satellite system during movement; wherein, both the starting position and the ending position of the movement are selected as points where the global navigation satellite system can directly obtain absolute coordinates; the global navigation satellite system directly obtains the absolute coordinates of the starting position at startup and the coordinates of the ending position at shutdown; a first processing module, connected to the combined measurement device, configured to process the observation data of adjacent frames to obtain the coordinate calculation result of the first target object of the current frame, and the coordinate calculation result includes the absolute coordinates of the first target object indoors; wherein, the first target object includes a positioning base station and / or a sensor; a second processing module, connected to the first processing module, configured to perform loop detection based on the observation data obtained during the movement from the starting position to the ending position to correct the coordinate calculation result of the first target object obtained during the movement to obtain a coordinate correction result; a storage module, connected to the second processing module, configured to save the absolute coordinates of the positioning base station and / or the sensor in the coordinate correction result; a third processing module, connected to the storage module, configured to calculate the absolute coordinates of the second target object based on the saved absolute coordinates of the positioning base station and / or the sensor; the first processing module includes: a matching unit, configured to perform feature matching on the image data of adjacent frames to obtain a matching result; a registration unit, connected to the matching unit, configured to perform registration processing on the point cloud data of adjacent frames to obtain a registration result; A calculation unit, respectively connected to the matching unit and the registration unit, is configured to obtain the coordinate calculation result of the first target object in the current frame to be recognized by combining the matching result, the registration result, the inertial data of the current frame, and the coordinate calculation result of the first target object in the previous frame; The first target object includes a positioning base station, and the second target object is a mobile vehicle; The third processing module is configured to calculate the absolute coordinate of the mobile vehicle based on the absolute coordinate of the positioning base station in the room and the principle of resection.

5. A system for establishing an indoor absolute coordinate system according to claim 4, wherein, The calculation unit further includes obtaining the optimized coordinate calculation result after being optimized by using a filter.

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