Method and system for using digital map data

Abstract

The present disclosure generally relates to a method and system for compensating for changes in the absolute position of a position relative to the earth's surface that occur over time due to crustal dynamics. The invention particularly, but not exclusively, relates to such compensation in the context of a method using digital map data, such as a method of vehicle positioning.

Description

Technical Field

[0001] The present disclosure generally relates to a method and system for compensating for changes in the absolute position of a position relative to the earth's surface that occur over time due to crustal dynamics. The invention particularly, but not exclusively, relates to such compensation in the context of a method using digital map data, such as a method of vehicle positioning. Background Art

[0002] A navigation system is a known and widely used technology that provides navigation support to users. The system is usually composed of a navigation client and a navigation server. A navigation client is a software application executed on a computing device. A navigation client can be implemented as a software application on various types of devices, including mobile devices, personal navigation devices, or in-vehicle computing devices. A navigation server provides information that supports the navigation client.

[0003] Navigation systems use digital maps to support drivers in reaching a desired destination. Such digital maps include segments connected by nodes, navigable elements (e.g., road elements) and junctions representing a navigable network (e.g., a road network). Digital map elements have associated navigation cost parameters. These are used to determine the cost of a path to a destination.

[0004] Digital maps that support navigation functionality may be referred to as standard definition maps (SD maps). Recently, it has been recognized that more accurate and detailed digital maps are needed to support certain advanced driving applications, such as autonomous driving applications or advanced driver assistance systems (ADAS). Such advanced driving applications require digital maps that provide highly detailed and accurate 3D lane-level details (including the geometry of lane markings, lane centerlines, and road boundaries). Digital maps used in such contexts may be referred to as high-definition (HD maps). HD maps extend the field of view of the vehicle and enable smoother, safer, and more efficient driving scenarios. HD maps can be used to meet a wide range of advanced driving applications. HD maps include arcs representing intersection areas and lane groups, and nodes describing the connections between arcs. Intersection areas and lane groups describe the road surface from one side to the other (and along one driving direction). Therefore, HD maps describe geospatial reality. Geospatial reality includes a collection of geospatial objects with associated geometries and attributes containing locations. Locations are expressed by coordinates in the context of a reference system, such as x, y, and z coordinates in ITRF2014. HD map information is expressed in approximately 10 -2 to 10 -1 These objects are described with a precision of meters.

[0005] HD map information is generated from a wide range of source data, such as satellite and aerial imagery, sensor data from mobile mapping vehicles, information provided by navigation clients, processed sensor data from vehicles, information from website sources, and crowd-sourced information. These data sources are usually pre-processed and validated before being used in the HD map information compilation process.

[0006] Both SD maps and HD maps can be subdivided into tiles and layers. A map tile describes a rectangular map area that contains map information related to the map area. A map layer contains a subset of the available map information. For example, an HD map may include an HD road layer, a speed limit layer, a "road check" layer, and a traffic sign layer. The HD road layer includes map information related to arcs (representing intersection areas and lane groups) and nodes (connecting arcs). The map information of the speed limit layer describes the speed limits. The traffic sign layer describes HD map objects that contain traffic-related information. The HD map objects in the traffic sign layer are also important for positioning as described below. HD maps contain additional layers. In summary, HD map information is structured into map layers and map tiles.

[0007] A tile for a specific HD map layer is a unit of transfer of map content between an HD map server and an HD map client in a vehicle. Such map content is delivered using well-known Internet content delivery methods (IP, HTTP, HTTPS, CDN, etc.) and map generation infrastructure (servers, cloud, etc.). In advanced driving applications (advanced driver assistance systems, autonomous driving), HD map information can be obtained using this delivery infrastructure. In order for the HD map application to know which HD map information to use, it first needs to determine the vehicle's position. Specifically, it needs to be delivered in a format equivalent to about 10 pixels of the object description in the HD map. -2 to 10 -1 The process of determining the vehicle's position in the real world, usually through sensors and HD maps, is called localization.

[0008] Real-time Kinematics (RTK) is a positioning technology that enhances the accuracy of position data derived from Global Navigation Satellite System (GNSS) signals. Figure 1 As displayed.

[0009] Figure 1A real-time motion module is presented, which includes a GNSS module and an enhanced precision module. The GNSS module (e.g., GPS, GLONASS, Galileo, BeiDou) receives satellite navigation signals from multiple satellites in view. It then uses these signals to calculate the distance to these satellites, which enables the GNSS module to determine an accurate position. The enhanced precision module of the RTK module obtains enhanced precision information from wireless data signals such as long-range wireless Internet data communication networks or similar wireless data transmission technologies. The GNSS module uses this precision enhancement information to improve the accuracy of positioning determined from received satellite signals. Enhanced precision data is typically associated with a specific period; an instant in time selected as a reference point (such as in astronomy). The RTK service provider defines the period associated with the precision enhancement information.

[0010] Another embodiment of localization uses onboard sensors in the vehicle, such as radar, lidar, sonar, odometers, and inertial measurement units. Advanced processing of the sensor data provides information about geospatial objects near the vehicle. These objects can be matched with HD map information to determine the location (and orientation) of the vehicle. The functional diagram of this localization embodiment is shown in FIG. Figure 2 As displayed.

[0011] Figure 2 An HD map positioning module consisting of an object detection module and a map object matching module is presented. The object detection module receives sensor data and processes it to extract information of relevant geospatial objects. The object detection module sends the detected objects to the map object matching module. The map object matching module compares the detected object information with the object information obtained from the HD map data. When a match is found, the map object coordinates are used to determine the positioning of the vehicle. Examples of this technology are described in WO2009098154 and WO2018104563. The map object matching module preferably only considers an area of ​​a few hundred meters around a rough estimate of the vehicle's positioning.

[0012] The matching of detected geospatial objects with the objects described in the HD map information produces the location and orientation of the vehicle on the map. HD map positioning gives positioning results with an accuracy range of 10 -2 to 10 -1 rice.

[0013] Some vehicles may use multiple positioning technologies, which use different technologies to increase the flexibility of positioning. Therefore, when one positioning technology provides inaccurate or no positioning information, the positioning can still be supported by another positioning technology.

[0014] When using digital map data, some problems may occur because the absolute position of geospatial features relative to the earth's surface varies over time due to crustal dynamics. Such movement may be the gradual movement of tectonic plates, and / or the result of more sudden movement (e.g., at plate boundaries) from earthquakes or other geological events. Not taking into account such effects may cause digital map data to become inaccurate over time. This may result in inconsistencies and inaccuracies in the methods using digital map data. Although the accuracy of digital map data is important in many applications, as described above, a particularly important application is the accuracy of positioning. If the digital map data used in this application is inaccurate, this may result in conflicts or inconsistencies between positioning results based on different technologies, and / or inaccuracies in the results of the positioning process. These problems may have serious consequences in some advanced driving applications, such as autonomous vehicle guidance or advanced driver assistance systems (ADAS).

[0015] Applicants have recognised that there is a need for methods that may be able to account for temporal changes in the absolute position of geospatial features relative to the Earth's surface due to crustal dynamics, for example when performing the method using digital map data. Summary of the invention

[0016] According to a first aspect of the invention there is provided a method of generating displacement map data for compensating for changes in the absolute position of a position relative to the surface of the earth over time due to crustal dynamics, the method comprising;

[0017] selecting a set of a plurality of reference positions in a geographic area covering at least a portion of the earth's surface, wherein the absolute positions of the reference positions relative to the earth's surface vary with time due to crustal dynamics;

[0018] obtaining position data indicating the absolute position of each reference location at different times;

[0019] and generating displacement map data using the position data indicating the absolute position of each reference position at the different times, wherein for each reference position the displacement map data comprises data indicating the time variation of the absolute position of the reference position.

[0020] The present invention in this aspect relates to a method for generating displacement map data for compensating for changes in the absolute position of a positioning relative to the surface of the earth due to crustal dynamics. The absolute position of a positioning refers to the real-world position of the positioning. The absolute position of a positioning referred to herein is the position of the positioning relative to a fixed reference system. The fixed reference system can be defined by a given coordinate system fixed relative to the surface of the earth. For example, the coordinate system can include longitude and latitude coordinates. Altitude can also be optionally considered. The fixed reference system is fixed, that is, defined relative to the surface of the earth, so that the position change of the positioning relative to the reference system corresponds to the position change of the positioning relative to the surface of the earth. Therefore, the position change of the positioning due to crustal dynamics (for example, the position change caused by the movement of tectonic plates associated with the positioning) will result in the position change of the positioning relative to the reference system. The reference system does not change due to crustal dynamics.

[0021] In an embodiment, a set of multiple reference fixes in a geographic area extending over at least a portion of the earth's surface is selected. Each reference fix is ​​a fix having an absolute position. As described above, the absolute position is a position in an absolute coordinate system defining a reference system. The reference system is a fixed reference system relative to the earth's surface. The absolute position refers to a real-world position. The absolute position may be, for example, a GPS position, or a position defined using any suitable standard absolute position reference system.

[0022] The absolute position of the reference location changes with respect to time. This change is a result of crustal dynamics. As described above, crustal dynamics can cause the absolute position of a geospatial feature to change over time. The crustal dynamics can be caused, at least in part, by the movement of tectonic plates. Such movement in the absolute position resulting from crustal dynamics can include continuous movement (e.g., gradual displacement) and / or can include sudden movement (e.g., sudden movement that can result from an earthquake). The rate of movement of the absolute position of a location can vary at different locations relative to the Earth's surface and / or relative to time.

[0023] The displacement map data is used to compensate for changes in the position of the fix over time due to crustal dynamics, wherein the absolute position of the reference fix changes over time due to crustal dynamics.

[0024] According to the invention, data indicating the absolute position of each reference fix is ​​determined at different times and displacement map data is obtained using the data, the displacement map data indicating the change in the absolute position of each reference fix over time. The change in the position of a reference fix between different times may be referred to as the displacement of the reference fix. The position of a reference fix at a given time may be defined by a set of coordinates. The change in the position of a reference fix over time may be the change in the coordinates of the reference fix over time.

[0025] Although the change in the absolute position of a fix relative to the surface of the earth is defined relative to a fixed reference system relative to the surface of the earth, and is a change in position in the real world, the position data indicating the absolute position of each reference fix at different times (and therefore the data indicating the change in the absolute position of the reference fix) can be determined relative to any desired reference system, as long as it indicates the absolute position of the fix relative to the surface of the earth, i.e., the absolute position at different times in the real world. For example, the reference fix may be defined relative to the reference system (i.e., the coordinate system of a digital map), or defined by reference to a real-world reference system, such as a GPS system or a vehicle reference system. However, in other embodiments, the position data is defined by reference to the fixed reference system itself. It is conceivable that the data indicating the change in absolute position may be relative to the same or a different reference system as the obtained position data indicating the absolute position of the reference fix.

[0026] Data indicating the time variation of the absolute position of a reference fix may be associated in the displacement map data with data indicating the absolute position of the reference fix at a reference time. The data indicating the absolute position of the reference fix may indicate the absolute position of the reference fix directly or indirectly, for example using an identifier of the reference fix from which the absolute position data can be obtained, and the data may be expressed relative to any desired reference system. For example, the data may be relative to a digital map. The absolute position of the reference fix is ​​the absolute position of the fix at a reference time. The data indicating the reference time is preferably also associated with a change in position data (i.e., displacement data of the reference fix). As mentioned below, data indicating the displacement of a reference fix relative to a plurality of different times may be obtained. In such embodiments, data indicating the displacement of the reference fix at each of a plurality of different times may be obtained, each displacement value (e.g., a vector) being associated with data indicating the time to which it is associated, and optionally associated with data indicating the absolute position of the reference fix at that time. The time to which the displacement data is associated may be a reference time, such as the time to which the displacement data applies, such as the time of generation of the data, or an initial time. Any arrangement capable of using the displacement data to determine the position of the location at a given time may be used.

[0027] The method comprises using the position data indicating the absolute position of each reference fix at different times to obtain data indicating changes over time of the absolute position of each reference fix. The displacement map comprises data indicating changes over time of the absolute position of each reference fix. The data indicating the changes in the absolute position of each reference fix may be referred to as "displacement" data.

[0028] Although the change in the absolute position of the reference fixes between different times may be one-dimensional, in embodiments, the difference is multi-dimensional, such as two-dimensional or three-dimensional. In embodiments, the data indicating the change in the absolute position of each reference fix over time comprises a set of one or more vectors. Each vector may be, for example, a two-dimensional or three-dimensional vector.

[0029] Position data indicative of the absolute position of each reference fix at different times is obtained. This data may be obtained for a first time and one or more subsequent times. Thus, in a simple embodiment, this data may be obtained (only) for a first time and a second subsequent time. However, obtaining this data for additional subsequent times may enable determination of changes in position of the reference fix with respect to time, and may facilitate determination of differences in the absolute position of the reference fix between any two times of interest being more readily available.

[0030] In some embodiments, the data indicating the change over time of the absolute position of the reference fix comprises a set of one or more displacement vectors, each displacement vector indicating a change in the absolute position of the reference fix between different times. Then, the step of generating the displacement map using the position data indicating the absolute position of each reference fix at different times may comprise obtaining a set of one or more displacement vectors for each reference fix, each displacement vector indicating a change in the absolute position of the reference fix between different times. The different times may be any pair of different times at which the position data indicating the absolute position of the reference fix is ​​obtained, for example, consecutive times thereof, or a first time and the or each subsequent time. Various exemplary embodiments are described below. In some embodiments, a plurality of displacement vectors may be obtained relative to each reference fix, each vector being for a different time pair, for example, consecutive times, or a first time and the or each subsequent time. Then, each displacement vector may be associated with its associated time (e.g., the later of the time pair used in determining the vector).

[0031] In an embodiment, the displacement map data comprises, for each reference fix, data indicating the displacement of the reference fix between a first pair of times,

[0032] Wherein for each reference location, the method comprises:

[0033] obtaining position data indicative of the absolute position of the reference position at each time in the first time pair;

[0034] determining a displacement of the reference position between the times in the first pair of times using the obtained position data indicative of the absolute position of the reference position at each time in the first pair of times, the displacement indicative of a difference in the absolute position of the reference position between the times in the pair of times;

[0035] and associating displacement data indicative of the displacement of the reference position with data indicative of the reference position.

[0036] Preferably, the displacement data comprises a displacement vector as described above.

[0037] The first time pair may be selected as desired. The first time pair comprises an earlier time, which may be referred to as the first time, and a later time, which may be referred to as the second time. The first time may be any time of interest for which displacement data is desired to be generated. The first time may be any reference time. The first time may be a reference time associated with a digital map. This time is referred to as the epoch of the map. The map represents the situation at a particular point in time, corresponding to the epoch of the map. This may be the time of generation of the digital map. This may enable the displacement map data to be used to determine the manner in which the position of a fix according to the digital map should be offset when the map data is used at a later time to take into account changes in the absolute position of the fix that may be expected to occur due to crustal dynamics. The second time may then be the time at which the map data will be used, for example, the time at which a fix is ​​performed using the data (i.e., the fix epoch). This may be the current time. Alternatively, the first time may be the time at which sensor data to be used in the map compilation process (i.e., the acquisition epoch). The second time may then be the time at which map compilation is performed (i.e., the map (generation) epoch). This may enable the displacement map data to be used to determine the manner in which the position of a location according to the sensor data should be offset when compiling the digital map using the sensor data to take into account changes in the absolute position of the location that may be expected to occur due to crustal dynamics. In other embodiments, the first time may be a digital map generation time (e.g. a map epoch) and the second time may be a time associated with the acquisition of sensor data for updating the digital map (e.g. an acquisition epoch). This may enable a map compiler to determine a displacement from a later acquisition time to an earlier map generation time in order to incorporate the acquired sensor data to update only a portion of the digital map without requiring an update of the entire map. The second time may be the current time or any desired reference time, for example when an offset to an earlier time / epoch is desired.

[0038] The method may comprise associating the displacement data with data indicating the later time of the first time pair, i.e. a second time. This time defines the time to which the displacement data applies. In effect, the displacement data of the reference fix provides a displacement map at the second time, indicating the displacement of the absolute position of the reference fix after the first time.

[0039] The displacement data is associated with data indicative of the reference fix. The data indicative of the reference fix may indicate the position of the reference fix at a reference time (e.g. the second time in the time pair). Thus, the displacement data may be associated with data indicative of the time to which it relates and with data indicative of the position of the reference fix at the time. This may enable the relevant displacement data to be easily identified when such data is needed later. However, it is conceivable that the data indicative of the reference fix may be associated with data indicative of the position of a reference fix at a different time (e.g. the first time in another context). The data indicative of the position of the reference fix may be in any desired reference system and may or may not be an absolute position, for example it may be a position relative to a digital map.

[0040] In a preferred embodiment, the method is repeated for at least one further time pair. Then, for each reference fix, the displacement map data may comprise data indicating the displacement of the reference fix between at least one further time pair, wherein the method comprises, for each reference fix, and for each further time pair;

[0041] obtaining position data indicative of the absolute position of the reference location at each time in the pair of times;

[0042] determining a displacement of the reference location between the times in the pair of times using the obtained position data indicative of the absolute position of the reference location at each time in the pair of times, the displacement indicative of a difference in the absolute position of the reference location between the times in the pair of times;

[0043] and associating displacement data indicative of the displacement of the reference position with data indicative of the reference position. The displacement data may comprise a displacement vector.

[0044] In these embodiments, each additional time pair comprises an earlier time and a later time. In some embodiments, the earlier time of each pair corresponds to the first time. Thus, a further displacement data set indicating the displacement of each reference position between the first time and a corresponding time of one or more subsequent times may be provided. However, this need not necessarily be the case. For example, displacement data may be obtained between a subsequent time and the later time of the time pair.

[0045] The method may comprise the step of associating the displacement data with data indicating a time to which the displacement data applies. The time may be the later of the pair of times. In this way, displacement data relating to a plurality of different times is provided, indicating the displacement of each reference position fix since the first time. When it is desired to obtain displacement data, the data relating to the time may be retrieved. These embodiments may be implemented by regularly updating the displacement map data.

[0046] The displacement data is associated with data indicative of the reference fix. The data indicative of the reference fix may indicate the position of the reference fix at a reference time (e.g., the second time in the time pair). This position may be relative to any desired reference system. Thus, the displacement data may be associated with data indicative of the time to which it relates and data indicative of the position of the reference fix at the time. This may enable the relevant displacement data to be easily identified when such data is needed later. In these embodiments, a set of multiple displacement values ​​(e.g., vectors) may be obtained for consecutive times.

[0047] In an embodiment, the method is repeated at successive times, wherein the later of each pair of times is the current time. Obtaining displacement data for a plurality of different times may be useful, as this may provide displacement data for the current time and one or more previous times. In embodiments where the earlier time used in deriving each set of displacement data is the same (e.g. a first time), this may provide an indication of the displacement of the absolute position of each reference position fix at various different times (e.g. map generation or sensor acquisition times) since the first time.

[0048] The method may simply be repeated at successive times to regularly update the displacement map data, such that the first time and the second time of the first time pair and the times of any subsequent time pairs may simply be arbitrary times. For example, the data may be determined using a first time pair corresponding to first and second times and then further time pairs, each further time pair comprising the first time and a subsequent time or between subsequent times. In each case, a set of displacement data applicable to a particular time is obtained, enabling the displacement of a position to be determined relative to the first time, or, in an embodiment, relative to either of the earlier times. Thus, although the times may correspond to times of events such as map generation, sensor acquisition, etc., the method may be performed without reference to such events, wherein the events are then used to retrieve applicable data when the displacement map data is subsequently used.

[0049] While in simpler embodiments the data indicative of the time-varying absolute position of a reference fix indicates position differences between one or more pairs of different times, in other embodiments it is contemplated that the data indicative of the time-varying absolute position of the reference fix may comprise a function indicative of the variation of the absolute position of the fix with respect to time.

[0050] Alternatively or in addition, in some embodiments, the data indicating the variation of the absolute position of the reference fix over time includes data indicating the rate of change of the absolute position of the reference fix (i.e., the speed or velocity of the reference fix). Then, the step of generating the displacement map using the position data indicating the absolute position at different times of each reference fix may include using the position data indicating the absolute position of each reference fix at different times to determine data indicating the speed of the reference fix. It will be appreciated that the data indicating the speed of the reference fix can be used to determine the difference (i.e., displacement) of the absolute position of the reference fix between a reference time and any future time of interest (or indeed a past time of interest). This only requires knowing the two times or time differences of interest. Such embodiments are particularly suitable for situations where the speed of the position of the reference fix is ​​constant with respect to time, or can be assumed to be constant. However, the speed is not necessarily constant. The data indicating the speed of the reference fix may indicate a function describing a time-varying speed. The method may include associating the data indicating the absolute position of the reference fix at a reference time with the reference fix for determining the displacement of the fix at the time of interest. It will be appreciated that in these embodiments, the displacement may be expressed in terms of rate or velocity.

[0051] In embodiments where the displacement map data comprises velocity data, it may provide a displacement velocity map. In embodiments where the data indicative of a change over time of the absolute position of the reference fix comprises data indicative of the velocity of the reference fix, the data preferably further comprises data indicative of a reference time. This may enable the displacement of the fix at any future time to be determined based on the difference between the time at which the displacement data is required and the reference time. The reference time may be the earliest of the different times used to determine the data indicative of the change in position of the reference fix.

[0052] The reference position may be any geospatial position for which, whether by measurement, modeling or a combination thereof, precise position data at different times and, therefore, accurate displacement values ​​are available. For example, in some embodiments, the reference position is a position of a permanent GNSS receiver, such as a Continuously Operating Reference Station (CORS) in the United States, or such a receiver operated by an RTK service (Real Time Kinematics).

[0053] The reference location is a real world location in a geographic area extending over a portion of the earth's crust.

[0054] A group of one or more reference locations may form a reference location network.

[0055] The reference fixes may be distributed uniformly or non-uniformly over a geographic region. For example, if a sub-region is associated with a lower degree of crustal activity, such as in the center of a large tectonic plate, then the reference fixes may be more sparse than a sub-region associated with a higher degree of crustal activity (such as at a plate boundary). In an embodiment, the reference fixes are distributed over a geographic region with a density that varies depending on the crustal activity within the geographic region. In regions with greater crustal activity, the density of the reference fixes is greater, and in regions with less crustal activity, the density of the reference fixes is less.

[0056] In some preferred embodiments, the reference fix group corresponds to the vertices of a set of triangles covering the geographic area. The set of triangles is preferably a tessellated triangle. In other words, the triangles fit together to cover the geographic area without leaving any gaps between triangles. The triangles may have the same or different areas. In a preferred embodiment, the density of the reference fixes, and therefore the areas of the triangles, varies across the geographic area.

[0057] It will be appreciated that the data indicating a change in the absolute position of the reference fixes defining the vertices of a triangle in such embodiments (i.e., displacement data of the reference fixes) may be used to estimate data indicating an expected change in the absolute position of any other fix covered by the triangle (i.e., an expected displacement). This includes fixes on or within the sides of the triangle. The method may include, for a fix of interest covered by one of the triangles and not corresponding to one of the reference fixes, using the data indicating a change in the absolute position of the reference fixes defining the vertices of the triangle to estimate data indicating an expected change in the absolute position of the fix. Such a method may be performed using interpolation. For example, this method may be performed by estimating the change in position using barycentric coordinate interpolation. The data indicating the expected change in the absolute position of the fix may be relative to any desired reference system, such as a map reference system.

[0058] In some embodiments, it is envisaged that the displacement map data may be provided as a displacement map data layer associated with a digital map. The digital map may be divided into a plurality of map tiles. In embodiments where the reference location corresponds to the vertices of a set of triangles covering the geographical area, the method may comprise: for each map tile, determining the or each triangle covering at least a portion of the geographical area covered by the map tile; and associating data indicative of the or each triangle with the map tile. The displacement data associated with the reference location defining the vertices of the or each triangle may then be used to determine the displacement data for the map tile. If the map tile is relatively large, it may encompass portions of a plurality of triangles. However, if the map tile is relatively small, the map tile may be located entirely within a single triangle.

[0059] In some embodiments where the map tile is within a single triangle, the method may include using the displacement data associated with the vertices of the triangle to determine a single displacement value for the map tile for each of one or more given times. The times may correspond to a first time pair for which displacement data was obtained and the or each later time in one or more further time pairs.

[0060] Whether or not an intermediate step involving triangles having the reference locations as their vertices is used, the method may include determining displacement data for each of the map tiles using the displacement map data, and associating the displacement data with the tiles. The method may include: obtaining data indicative of a plurality of digital map tiles; determining displacement data for each of the map tiles using the displacement map data; and associating, for each map tile, the displacement data with the tile. A single displacement value may be obtained for each map tile for each of one or more given times. The times may correspond to the or each later time of a first time pair and one or more further time pairs for which displacement data was obtained.

[0061] In these embodiments, the displacement values ​​may be distributed as a grid indicative of the map tiles.Since the displacements of relatively close tiles may be assumed to be similar, any suitable compression technique may be applied to the displacement map data.

[0062] The invention extends to using displacement map data obtained according to any of the embodiments of the invention described herein.

[0063] The displacement map data may be useful in various contexts involving digital map data.

[0064] According to a further aspect of the invention, there is provided a method of transforming the position of one or more locations of interest from a first reference system to a second reference system, wherein at least one of the first and the second reference systems is a reference system associated with a digital map covering a geographical area containing the locations of interest, wherein the position of the locations of interest relative to the at least one of the first and the second reference systems is a position relative to the digital map;

[0065] The method comprises, for the or each location of interest:

[0066] obtaining data indicative of the position of the location of interest relative to the first reference system;

[0067] obtaining displacement map data, the displacement map data comprising, for each of one or more locations, data indicative of changes in the absolute position of the location relative to the earth's surface that occur over time due to crustal dynamics;

[0068] and determining data indicative of the position of the location of interest relative to the second reference system using the obtained data indicative of the position of the location of interest relative to the first reference system and the displacement map data;

[0069] wherein the step of using the obtained data indicating the position of the location of interest relative to the first reference system and the displacement map data to determine data indicating the position of the location of interest relative to the second reference system comprises using the displacement map data to adjust the position of the location of interest when transforming the position of the location of interest from the first reference system to the second reference system;

[0070] And wherein the method further comprises generating for output data indicative of the determined position of the location of interest relative to the second reference system.

[0071] Although the present invention will be described with respect to transformation of locations of interest between reference frames, it will be appreciated that any of the steps or other features described herein may be applicable to transformation of any further locations of interest taking into account a plurality of locations of interest.

[0072] The displacement data is used to compensate for changes in the corresponding absolute position of the location of interest that occur in the real world due to crustal dynamics.

[0073] Each of the first and second reference systems is associated with a respective coordinate system. The reference system may be defined by the coordinate system. The position of the location of interest relative to each reference system may be defined relative to a coordinate system associated with the respective reference system. The coordinate systems associated with the first and second reference systems may be referred to as the first and second coordinate systems.

[0074] The invention is particularly applicable to transforming the position of one or more locations of interest between a reference system used by a vehicle and a reference system used by a digital map (in either direction). This may enable the position of a location of interest determined relative to the reference system of the vehicle to be determined relative to a digital map, or vice versa.

[0075] The vehicle reference system is a reference system that is common to all systems in the vehicle. Such systems may include a positioning system. The vehicle reference system is a reference system that is defined relative to the real world. The reference system may be an absolute reference system. This may be, for example, a standard reference system, such as a GPS-based reference system. However, in other embodiments, the reference system may be any arbitrary reference system that is common to all systems in the vehicle. In contrast, the digital map reference system is a reference system that is defined relative to the representation provided by the digital map of the real world.

[0076] In some preferred embodiments, one of the first and second reference systems is a reference system associated with a digital map, and the other of the first and second reference systems is a reference system associated with a vehicle. The method is preferably performed as part of a process of locating the vehicle. The term "localization" refers to a process involving determining the position of a vehicle in the real world. The vehicle may be a vehicle traversing a path of a navigable network represented by the digital map.

[0077] The digital map (or any digital map referred to herein) may include a plurality of segments connected by nodes, the segments representing elements of a navigable network in the geographic area covered by the digital map. References to a vehicle traversing a path of the navigable network should be understood to refer to a vehicle traversing the navigable network in any manner and not necessarily along a predetermined route.

[0078] In some embodiments, the location of interest is the location of an object encountered or expected to be encountered by the vehicle while traversing a path of the navigable network. The object may be an object used for positioning purposes, such as a feature such as a road sign, a traffic light, a road marking, etc. The object may be an object detected by a vehicle system. The object is a real-world object.

[0079] The positions of objects in the vicinity of the vehicle encountered (i.e. detected) by the vehicle while traversing a path of the navigable network may desirably be transformed from a vehicle reference frame in which the objects were detected, for example, by a vehicle system (e.g. by a set of one or more sensors thereof) to positions relative to a digital map covering a geographic area containing the position of the objects. In other words, the positions may be "map matched". The objects are real world objects. Where the positions of objects are map matched, this may be used to determine the position of the vehicle in the real world (which may or may not involve the intermediate step of determining the position of the vehicle relative to the digital map). The object positions may be used together with other information to determine the position of the vehicle.

[0080] When transforming the position of the location of interest from the first reference system to the second reference system, the position of the location of interest is adjusted using the displacement map data. The adjustment of the position of the location of interest may provide a transformation between systems, or may be performed as part of such a transformation. The transformation may involve other adjustments, such as relating positions between the different coordinate systems. However, in some embodiments, the adjustment of the position of the location of interest may define the second reference system, such as in embodiments where the position of a map object is adjusted to "shift" the map.

[0081] In some preferred embodiments, the location of interest is the location of an object near the vehicle that the vehicle encounters while traversing a path of the navigable network. In this case, the object is a real-world object. The term "encountered" encompasses objects detected, for example, by any one or more sensors associated with the vehicle. The position of the location of the object may be a position detected by a vehicle system, for example, based on data obtained from a set of one or more sensors associated with the vehicle, in a reference frame associated with the vehicle.

[0082] Conversely, in other contexts, it may be necessary to transform digital map object (e.g., map objects indicating objects that the vehicle is expected to encounter for positioning purposes while traversing the navigable network, such as features such as road signs, traffic lights, road markings, etc., whether or not the objects are in the vicinity of the vehicle) data from the map reference system to the vehicle reference system. The map object may indicate an object that is expected to be encountered at a future time. For example, the vehicle may need to determine whether the object is detected by its system at an expected location relative to the vehicle.

[0083] Certain processes involving transforming the position of, for example, an object in the real world or a location of interest of a map object between reference systems (e.g., a coordinate system associated with the vehicle and a coordinate system of a digital map) to help determine the position of the vehicle in the real world may be referred to as "localization" processes. The determination of the position of the object may be used to confirm an expected position of the vehicle in the real world, or to obtain the position of the vehicle in the real world where no previous estimate of it exists. Such processes may use the digital map data in combination with data related to real-world positions (e.g., sensor data, such as data obtained by a localization system associated with the vehicle).

[0084] In an embodiment in which the data generated indicates the position of an object detected in the vicinity of the vehicle in a second reference system, which is the reference system of a digital map, the method may involve again transforming the position of the object in the map reference system into the vehicle reference system in order to use the position of the object to determine the position of the vehicle in the real world.

[0085] The method may comprise using the displacement map data to compensate for changes in the absolute position of the location of interest relative to the earth's surface that are expected to have occurred since the digital map was generated when determining the location of interest relative to the second reference system.

[0086] This may be performed in various ways and at various times in the process of obtaining the position of the location of interest relative to the second reference system. For example, the position of the location of interest relative to the first reference system may be transformed to a position relative to the second reference system, and then the determined position relative to the second reference system may be adjusted using the displacement map data. In other embodiments, the adjustment using the displacement map data may occur in the first reference system before the position of the location of interest is transformed to the second reference system. In some embodiments, before or after determining the position of the location of interest relative to the digital map, the digital map data is adjusted as a whole to compensate for changes in the absolute position of the locations therein using the displacement map data, rather than individually adjusting the position of the location of interest in any reference system to compensate for changes in the absolute position of the location of interest in the real world.

[0087] In some embodiments, the second reference system is a reference system associated with the digital map, and the first reference system is associated with a vehicle traversing a path of a navigable network represented by the digital map. When transforming the position of the location of interest from the first reference system to the second reference system, the displacement map data may be used to adjust the position of the location of interest to compensate for changes in the corresponding absolute position of the location of interest relative to the surface of the earth (in the real world) that are expected to occur due to crustal dynamics since the digital map was generated. The method may then include transforming the position of the location of interest relative to the first reference system to a position relative to the second reference system, and using the displacement map data to adjust the position of the location of interest relative to the second reference system to compensate for changes in the corresponding absolute position of the location of interest relative to the surface of the earth (in the real world) that are expected to occur due to crustal dynamics since the digital map was generated. The position of the location of interest relative to the first reference system may be obtained by a vehicle system (e.g., by a set of one or more sensors thereof). The location of interest may correspond to the position of an object detected by the vehicle system. The adjusting step may be performed as part of a process of map matching the object. In some embodiments, the first reference system is a reference system associated with the digital map. The displacement map data may be used to adjust the position of the location of interest when transforming the position of the location of interest from the first reference system to the second reference system to compensate for changes in the corresponding absolute position of the location of interest relative to the Earth's surface (in the real world) that are expected to occur after the digital map is generated due to crustal dynamics.

[0088] The method may then include transforming the position of the location of interest relative to the first reference system to a position relative to the second reference system, and using the displacement map data to adjust the position of the location of interest relative to the second reference system to compensate for changes in the corresponding absolute position of the location of interest relative to the Earth's surface (in the real world) that are expected to have occurred since the digital map was generated due to crustal dynamics.

[0089] In other embodiments where the first reference system is a reference system associated with the digital map, the method may include;

[0090] The displacement map data is used to adjust the position of the location of interest relative to the first reference system to compensate for changes in the corresponding absolute position of the location of interest relative to the earth's surface that are expected to have occurred due to crustal dynamics since the digital map was generated, and then the adjusted position of the location of interest relative to the first reference system is transformed into a position relative to the second reference system.

[0091] It can therefore be seen that adjusting the position of the location of interest to compensate for expected changes in the absolute position of the location in the real world due to crustal dynamics may occur before, during or after transforming the position of the location to a second (i.e., vehicle) reference frame.

[0092] It will be appreciated that in these embodiments, the position of the location of interest relative to the first reference system may be obtained by map matching data indicative of the location of interest obtained by a vehicle system (e.g. by a set of one or more sensors thereof). This position obtained by the vehicle system may be in a second (i.e. vehicle) reference system. Thus, an initial transformation of the location's position data may occur in order to obtain the position data in the first (digital map) reference system for transformation into the second reference system to compensate for changes in the real world position of the location of interest.

[0093] In embodiments in which the first reference system is a reference system associated with the digital map, the method may comprise obtaining the position of a location of interest relative to the second reference system (i.e., the reference system of the vehicle system), and transforming the position of the location of interest relative to the second reference system to the first reference system associated with the digital map to obtain the position of the location of interest relative to the first reference system, which is then transformed back to the second reference system in any of the described manners in order to compensate for changes in the position of the location in the real world.

[0094] In some embodiments where the first or second reference frame is a reference frame associated with the vehicle, the location of interest may be a location of an object encountered by the vehicle while traversing a path of the navigable network. The object may be an object detected by a vehicle system.

[0095] However, in other embodiments where the first reference system is a reference system associated with the digital map, the method may be performed in response to receiving a request for map object data. The position may then be a position of a map object. This request may be received from a vehicle system (e.g., from an HD map client). In these embodiments, the position of interest in the first reference system to be transformed in a manner to compensate for changes in the position of the position in the real world that occurred after the digital map was generated may be a position of a map object requested by a vehicle (e.g., a vehicle system). The method may include providing data indicative of the map object to the vehicle, the data comprising a determined position of the position of the map object in the second reference system (adjusted to compensate for changes in the absolute position of the position in the real world due to crustal dynamics since the map was generated). The request for map object data may indicate a position of a map object in a first or second reference system (i.e., the reference system of the digital map or the vehicle system). If the request is received in the second vehicle system reference system, the method may involve an initial step of transforming the position of the map object in the second reference system to a position in the first reference system.

[0096] In these embodiments, the method may further include determining displacement data indicating a change in the absolute position of the location relative to the earth's surface due to crustal dynamics since the digital map was generated, and associating the displacement value with the data indicating the position of the map object in a second reference system. This data may be provided to any vehicle system (e.g., an HD map application). The system may be the same as or different from the vehicle system requesting the data. Therefore, in embodiments, the method may further include determining displacement data indicating a change in the real-world position of the location since the digital map was generated, and associating the displacement data with data indicating the position of the map object in the second reference system, and optionally providing the displacement data to the vehicle together with the data indicating the position of the map object in the second reference system.

[0097] In some embodiments, each of the first and second reference systems is associated with a digital map. The digital maps may be the same digital map. The method may then include using the displacement map data to compensate for changes in the absolute position of the location of interest in the real world that are expected to have occurred since the digital map was generated to define the first reference system. The method may involve shifting the digital map to a second reference system.

[0098] In some embodiments, the method is performed relative to a plurality of locations of interest, each location of interest being a location of a map object of a digital map, wherein each of the first and second reference systems is associated with the digital map. In these embodiments, the first and second reference systems are reference systems defined by the digital map before and after the locations of map objects therein are adjusted using the displacement map data to compensate for changes in corresponding absolute positions of map objects in the real world relative to the earth's surface that are expected to have occurred attributable to crustal dynamics since the digital map was generated. The step of obtaining data indicative of the position of each location of interest relative to the first reference system may comprise obtaining digital map data in the first reference system, the digital map comprising the map objects;

[0099] The position of each map object relative to the digital map is determined in a first reference system, and the position of each map object is adjusted using the displacement map data to compensate for changes in the corresponding absolute position of the map object in the real world relative to the earth's surface that are expected to have occurred attributable to crustal dynamics since the digital map was generated, thereby shifting the reference system of the digital map from the first reference system to a second reference system. The first and second reference systems may be reference systems defined by a reference time associated with the map (e.g., a map epoch, such as the time of generation of the map), and at a subsequent time of interest (e.g., a location time).

[0100] The method compensates for changes in the corresponding absolute positions of map objects relative to the earth's surface that may have occurred since the digital map was generated in the first reference frame due to crustal dynamics. Depending on whether the map objects represent real-world objects, the method may compensate for changes in the corresponding positions of map objects in the real world, which may or may not correspond to the absolute position of the object in the real world represented by the map objects.

[0101] Such embodiments are believed to be inherently advantageous. According to a further aspect of the invention there is provided a method of adjusting digital map data to compensate for changes in the absolute position of a location relative to the earth's surface which may be expected to have occurred since the digital map was generated due to crustal dynamics, the method comprising;

[0102] obtaining digital map data, said digital map data comprising data indicative of said locations of a plurality of map objects;

[0103] obtaining displacement map data, the displacement map data comprising, for each of one or more locations, data indicative of changes in the absolute position of the location relative to the earth's surface that occur over time due to crustal dynamics;

[0104] The position of each map object relative to the digital map is determined, and the position of each map object is adjusted using the displacement map data to compensate for changes in the corresponding absolute position of the map object relative to the earth's surface that are expected to have occurred due to crustal dynamics since the digital map was generated.

[0105] The invention in this further aspect may comprise any or all of the features described with respect to the other aspects and embodiments.

[0106] In any of the embodiments of the invention relating to determining adjusted digital map data, the method may comprise using the adjusted data in a map matching process.

[0107] The method may include: receiving a request from a vehicle for map data indicating a location of an object encountered by the vehicle; determining the location of the object relative to the digital map data in the second reference system; and providing data indicating the location of the object to the vehicle using the determined data. In some embodiments, the step of providing the data indicating the location of the object to the vehicle using the data may include transforming the location of the object from the second reference system back to the first reference system, or providing the vehicle with the location data in the second reference system. Thus, in these embodiments, the shifted map data may be used to provide the vehicle with compensated location data for map objects for any number of map objects, rather than requiring compensation for changes in the location of the map objects since the map was generated to be performed on an object-by-object basis.

[0108] The method may include the vehicle determining a position of the vehicle using the data indicative of the position of the object provided thereto.

[0109] According to any of the aspects or embodiments of the invention, the method may include determining the position of the vehicle in the real world (e.g., relative to a navigable network) using the generated data indicating the determined position of the location of interest relative to the second reference system. The generated data may be used directly or indirectly for this determination. The data may be used with other data as part of the positioning process, such as data indicating the location of other objects (whether map objects or real-world objects), and / or other types of data. Positioning may involve using data from multiple sources.

[0110] Once the position of the vehicle is determined, this may be used in various ways, for example for navigation purposes, incorporating advanced driver assistance or automated driving methods, or obtaining digital map data relating to the position of the vehicle, etc.

[0111] The digital map defining one (or both) of the reference frames may be any suitable digital map used in the context of applying the present invention. In a preferred embodiment of the present invention in the context of vehicle positioning, the digital map may be a so-called "high definition" digital map. Such maps provide a highly detailed and accurate representation of a navigable network, including lane level details such as lane marking geometry, lane centerlines, road boundaries, etc. Such maps may be suitable for use in implementation schemes of ADAS (Advanced Driver Assistance Systems) and / or autonomous vehicle guidance applications. The digital map data may be based on map data compiled over time by a map source provider. This map data may be compiled using information obtained from various sources, including but not limited to; satellite and other aerial imagery data (for basic road geometry), dedicated mapping vehicle fleets, navigation applications run by devices associated with vehicles traversing a navigable network, website sources, and crowdsourcing.

[0112] The digital map data is associated with a reference time. The reference time may be referred to as a map epoch. The map identifies circumstances of the map epoch. The map epoch typically corresponds to the time of generation of the map. However, in some cases, the map epoch will be an earlier reference time at which the map data is adjusted when it is generated. The generation time may correspond to the time when the map is compiled. It may be assumed that the digital map provides an accurate representation of a geographic area, such as an accurate representation of a navigable network in a geographic area, at the time of its generation or at the map epoch (if different). However, since the compilation and maintenance of digital map data may involve a great deal of time and resources, updates of the digital map data may not be performed frequently. When the digital map data is used, for example, by a positioning system associated with a vehicle, a period of time may have passed. As described above, due to movement of the position of a real-world positioning that may occur in the intervening period (e.g. due to crustal dynamics), the digital map may no longer accurately represent the position of the positioning in the real world. The present invention uses displacement map data to adjust for any such changes that may have occurred in the position of the real-world positioning (i.e., the absolute position of the positioning). This enables the digital map to be used for a longer period of time without being updated.

[0113] According to any of the embodiments of the present invention, the method described herein may include using the displacement map data to compensate for changes in the absolute position of the location of interest in the real world that are expected to have occurred between the generation of the digital map (or the map epoch, if different) and any time of interest when transforming the position of the location of interest from the first system to the second reference system. The time of interest is preferably the current time. The current time may be, for example, the time at which the positioning system of a vehicle requires the transformed position data in the second reference system. Any reference herein to adjusting the position of the location of interest to compensate for changes that have occurred since the time of map generation may be modified to refer to any reference time associated with the map, such as the map epoch, if different. The map represents a navigable network at the time of the map epoch.

[0114] The displacement information that may be provided by the displacement map is also useful in the context of compiling a digital map. A digital map may be compiled from a plurality of data sources. The digital map may be based at least in part on sensor data indicating the position of a location of an object collected at one or more times prior to the time of compilation of the digital map. The displacement map data provides a way of compensating for position changes of the location of the object that may have occurred between the time of collection of the sensor data and the time of compilation of the map based on the sensor data.

[0115] Such embodiments are believed to be advantageous in themselves. According to a further aspect of the present invention, there is provided;

[0116] A method for compiling a digital map,

[0117] The method comprises:

[0118] acquiring, at a first time, sensor data indicating a location of one or more objects;

[0119] and compiling a digital map at a subsequent time using said acquired sensor data;

[0120] The method comprises:

[0121] obtaining displacement map data, the displacement map data comprising, for each of one or more positions, data indicating a change over time of the position relative to the absolute position of the earth's surface due to crustal dynamics;

[0122] and, in compiling the digital map, using the displacement map data to adjust the position of the or each object's location to compensate for changes in the object's location relative to the corresponding absolute position of the Earth's surface that are expected to have occurred due to crustal dynamics since the sensor data was acquired.

[0123] The sensor data may indicate the position of the one or more objects in the real world, i.e. the absolute position. The method may be performed relative to sensor data indicating the position of one or more objects acquired at different times, wherein the position of the or each object's location is appropriately adjusted using the displacement data at each time.

[0124] The step of compiling the digital map may comprise using the acquired sensor data and data from one or more other sources.

[0125] In this further aspect, the invention may include any or all features described with respect to other aspects and embodiments of the invention, provided they are not mutually exclusive.

[0126] According to another aspect of the present invention, a method for updating a digital map is provided.

[0127] The method comprises:

[0128] acquiring, at a first time, sensor data indicating a location of one or more objects;

[0129] and updating a digital map generated at an earlier time using said acquired sensor data;

[0130] The method comprises:

[0131] obtaining displacement map data, the displacement map data comprising, for each of one or more positions, data indicating a change over time of the position relative to the absolute position of the earth's surface due to crustal dynamics;

[0132] and, when updating the digital map, adjusting the position of the or each object's location using the displacement map data to compensate for changes in the corresponding absolute position of the object's location relative to the Earth's surface which are expected to occur due to crustal dynamics between generating the map and acquiring the sensor data.

[0133] In these further aspects, the sensor data is adjusted to an earlier map generation time (e.g., a map epoch) so that it can be used to update the map, but in a manner that adjusts the sensor data to compensate for changes attributable to crustal dynamics so as to reflect the position of the object detected at the earlier map generation time.

[0134] In this further aspect, the invention may include any or all features described with respect to other aspects and embodiments of the invention, provided they are not mutually exclusive.

[0135] The displacement map data used in any of the aspects or embodiments of the invention may comprise data obtained according to any of the previously described embodiments.The data used may be at least a part of the obtained displacement map data.

[0136] In some preferred embodiments, the one or more positions for which absolute position change data is provided are reference positions. The reference positions may correspond to any one or more reference positions for which displacement map data is obtained. In an embodiment, for each of a plurality of reference positions, the displacement map data comprises data indicating the time variation of the absolute position of the reference position. However, it is conceivable that absolute position change data, i.e. displacement data, may be provided only for one position. The position may be an area of ​​a map tile, for example, as described below, or may be a position within such a map tile. Therefore, the position to which the displacement map data used in these further aspects relates may or may not be the reference position used when generating the displacement map data, depending on the manner in which the displacement map data is obtained based on the reference position, for example, whether it is used to provide displacement map data tile by tile, etc. In tile-based embodiments, the displacement data obtained for a plurality of reference positions may be used to obtain one or more displacement values ​​for a tile. In the case where the one or more positions do correspond to one of the reference positions of the previous embodiment, it should be understood that it does not necessarily correspond to all reference positions. Therefore, the displacement map data may be only (the relevant part of) the entire displacement map data. Likewise, the digital map data used in accordance with the invention relates to a geographical area and may form part of a larger digital map, for example so that only the data in the vicinity of a location of interest is taken into account.

[0137] The method may include, in the context of the present invention, using the displacement map data to determine data indicating an expected change in the absolute position of the location of interest (or the position of an object in a map compilation embodiment) between times of interest (e.g., between the current time and the time when the map was generated (or map epoch time) or the time when sensor data was acquired). The data indicating the expected change in the position of the location of interest between times of interest may be referred to as displacement data and may be, for example, a displacement value. The times of interest may be referred to as "epochs", such as acquisition epochs, generation epochs, etc. An epoch refers to a particular point in time that provides a reference time point.

[0138] The method may include using the current time and data indicating the location of the location of interest (or the location of an object) to obtain this data using the displacement map data. The location of the location of interest may be a location relative to either reference system, depending on when the adjustment based on the displacement data occurs. For example, in some embodiments, the adjustment may be made after the location is transformed from the first reference system to the second reference system, although the adjustment usually occurs when the location is in the first reference system. In practice, since the displacement data does not change significantly over a small distance, small differences between locations in different reference systems will not be meaningful. In the case where the first and second reference systems are defined by digital maps, the location of the location of interest will be defined by the first reference system. In some embodiments where the displacement data (e.g., displacement values) are associated with a map tile covering the location of interest, the method may include using data indicating the location of the location of interest to obtain the displacement data associated with the map tile covering the location of interest. The data indicating the absolute position change may be based on the first or second reference system, or indeed based on another reference system, such as a fixed reference system relative to the surface of the earth, if different.

[0139] The method may include using data indicating changes in absolute position with respect to one or more fixes (e.g., reference fixes) (i.e., displacement data) to determine data indicating expected changes in absolute position of a fix of interest between times of interest (e.g., displacement values). For example, the data (e.g., displacement values) may be obtained by an interpolation process based on displacement data with respect to one or more (and optionally multiple) fixes (e.g., reference fixes) for which the displacement data is provided.

[0140] The data indicative of changes in the absolute position of a fix (eg, a reference fix) over time may include a set of one or more displacement vectors, each displacement vector indicating a change in the position of the reference fix between different times.

[0141] Determining displacement map data relating to displacements occurring between times of interest may be achieved in any desired manner. For each of a plurality of reference fixes, the displacement map data may include data indicating the displacement of the reference fix between a reference time and one or more subsequent times. The reference time and one of the subsequent times may correspond to a time of interest. For example, in embodiments relating to the compilation of a map, the reference time may be the time of generation of a digital map to which adjustment is required or the time of acquisition of sensor data. Alternatively, the method may include deriving data relating to the time of interest or times from the displacement map data. This may involve some form of inference from data relating to different times present in the displacement map data or using a reference time where provided.

[0142] In an embodiment, the data indicating the time-varying change in the position of each fix includes data indicating a speed (e.g., a velocity of the fix (e.g., a reference fix)). The method may include using the speed (e.g., a velocity of the fix (e.g., a reference fix)) to determine displacement data for the fix of interest.

[0143] In an embodiment where a set of reference locations of the displacement map data corresponds to the vertices of a set of triangles covering a geographic area, the method may include identifying one of the triangles that covers the location of interest. When the location of interest is located on or within the edge of a triangle, the location of interest may be considered to be covered by a triangle. The method may include, for a location of interest covered by one of the triangles and not corresponding to one of the reference locations, using the data indicating the change in the position of the reference locations defining the vertices of the triangle to estimate data indicating an expected change in the location of the location. Such a method may be performed using interpolation. For example, this method may be performed by estimating the position change using barycentric coordinate interpolation.

[0144] In some embodiments, it is envisaged that the displacement map data may be provided as a displacement map data layer associated with a digital map. The digital map may be divided into a plurality of map tiles. In some embodiments, each map tile is associated with displacement data applicable to any location of interest within the area of ​​the map tile. The method may then comprise obtaining the displacement data associated with the map tile, and using the displacement data to provide data indicative of an expected change in position of the location of interest. Where displacement data for different times is associated with the map tile, the method may comprise obtaining the displacement data for the applicable time.

[0145] In other embodiments involving map tiles and in which the reference locations of the displacement map data correspond to vertices of a set of triangles covering a geographic area, each map tile may be associated with data indicating one or more triangles at least partially covered by the map tile. The data may be any suitable reference for a triangle. The method may then include obtaining the triangle data and using the data to obtain displacement data for the location of interest as described above.

[0146] Any of the above features related to obtaining displacement data about a location of interest are equally applicable to obtaining displacement data about the location of an object in the aspects related to mapping.

[0147] As described above, the term "absolute position" as used herein refers to a real-world position relative to the surface of the earth, such as defined by a fixed reference system defined relative to the surface of the earth. The reference system may be defined by a fixed coordinate system.

[0148] Any steps referred to herein as obtaining digital map data or displacement map data may comprise accessing the digital map data from locally stored data, or in a preferred embodiment the method comprises obtaining said digital map data or displacement map data from a server.

[0149] However, the digital map and displacement map data are obtained, the displacement map data may be provided as separate digital map data to a digital map including the location of interest, or may be provided as a map layer thereof. In some embodiments, the method comprises receiving digital map data from a server, the digital map data comprising the digital map data and the displacement map data, optionally wherein the displacement map data forms a layer of the digital map data.

[0150] The digital map data may indicate a complete digital map covering a geographical area, or may be in the form of tiles. A map tile forms part of a larger map that has been subdivided into a plurality of tiles. This may facilitate processing, such as being a relevant tile or tiles, e.g. based on, for example, the current or other interesting location of a device that is to use the tile. Thus, a geographical area may be a sub-area of ​​a geographical area covered by a digital map.

[0151] It will be seen that the displacement map data described herein provides a representation of displacements due to, for example, construction movement, which can be (and preferably is) maintained and updated separately from the rest of the map information.

[0152] In this way, the life cycle of digital maps can be increased. For example, it will be appreciated that a large amount of resources must be invested in developing accurate digital maps, and that attempting to update digital maps more regularly is generally undesirable. In contrast, taking such absolute displacements into account by using displacement maps means that only the displacement maps (layers) need to be generated and delivered frequently.

[0153] The techniques presented here are generally applicable to any context in which it is desirable to provide accurate positioning of a vehicle within a road network and / or to generate an accurate map including information about the local environment of the road network. However, embodiments are particularly directed to techniques for locating an autonomous vehicle (e.g., a vehicle that requires minimal (or no) driver interaction). For example, in embodiments, the results of the positioning may be provided to an autonomous driving module of the vehicle for navigation and motion planning, i.e., autonomous driving. Thus, the vehicle may include an autonomous driving vehicle traveling in a road network, such as an autonomous driving car or truck, etc. However, it should be appreciated that the present technology may also find practical value in various other contexts, such as in contexts associated with non-autonomous driving vehicles or semi-autonomous driving vehicles. For example, it is also contemplated that positioning may generally be used as part of any appropriate advanced driver assistance system, for example, in the case where it is desirable to accurately locate the vehicle within a map. In addition, it should be appreciated that the mapping results do not need to be used for (although preferably will be used for) the purpose of facilitating autonomous driving, and may be used to generate improved maps for navigation for desired use by any vehicle, such as as part of a conventional navigation guidance system.

[0154] A road network is typically a network of multiple interconnected roads that can be navigated by a vehicle. A road network can typically be represented by a digital or electronic map (or mathematical graph). A digital map in its simplest form is effectively a database containing data representing nodes (most commonly representing road intersections) and lines between those nodes representing the roads between those intersections. In more detailed digital maps, lines can be divided into segments defined by start and end nodes. These nodes can be "real" in their representation of road intersections where at least three lines or segments cross, or can be "fake" in their provision as anchor points for segments that are not defined at one or both ends by real nodes to provide (among other things) shape information for a particular section of road or a component that identifies a certain characteristic of that section of road (e.g., speed limit) at which the location changes. In almost all modern digital maps, nodes and segments are further defined by various attributes, which are in turn represented by data in a database. For example, each node will typically have geographic coordinates to define its real-world location, e.g., latitude and longitude. The nodes also typically have maneuver data associated with them, which indicates whether it is possible to move from one road to another at an intersection. For the purposes of conventional navigation guidance, for example, as may be provided by known portable navigation devices, a segment of a digital map need only (and typically will only) contain information about the centerlines of the roads, although each road segment may also be supplemented with attributes such as the maximum speed allowed, lane size, number of lanes, whether there are dividing barriers between them, etc. However, in accordance with embodiments of the present invention, as will be further described below, a digital map may be generated (or used) that provides a more accurate and realistic representation of the road contour including lane centerlines and lane connectivity (i.e., lane markings), as well as other key elements (e.g., the three-dimensional geometry of the road network, such as landmark objects that may be desirably incorporated into the map). This type of digital map may be referred to as an "HD" map (as compared to a conventional "SD" map that contains road centerlines but not lane centerlines). The additional information contained in an HD map (and at least the lane markings) is typically required for the purposes of autonomous driving.

[0155] However, the use of these HD maps is not limited to autonomous vehicles, and these maps may also find suitable application in any other application where it is desirable to provide an improved and more accurate representation of road contours, including but not limited to various advanced driver assistance system applications. Thus, the HD maps may also contain data representing any other features that may be appropriately and desirably presented to a user, or an autonomous driving system or other advanced driver assistance system (ADAS).

[0156] The various functions of the technology described here can be performed in any desired and suitable manner. For example, the steps and functions of the technology described here can be implemented in hardware or software as needed. Therefore, for example, unless otherwise indicated, the various processors, functional elements, levels and "components" of the technology described here may include any suitable processor or several processors, controllers or several controllers, functional units, circuits, processing logic, microprocessor arrangements, etc. that can be operated to perform various steps or functions, etc., such as suitable dedicated hardware elements (processing circuits) and / or programmable hardware elements (processing circuits) that can be programmed to operate in a desired manner. For example, the components for performing any of the steps of the method according to any aspect or embodiment described herein may generally include a group of one or more processors (or processing circuits), which are configured (e.g., programmed with a computer-readable instruction set) for doing so. A group of processors that are the same or different from any other step can be used to perform a given step. Any given step can be performed using a combination of processor groups. The system may further include a data storage component (e.g., a computer memory) for storing (e.g.,) at least one repository containing indicative and informational data. Software (e.g., a computer program) may be used at least in part to implement any of the methods according to the present invention. Therefore, the present invention also extends to a computer program product comprising computer readable instructions executable to perform or cause a system and / or server to perform a method according to any of the aspects or embodiments of the present invention. Therefore, the present invention extends to a preferably non-transitory computer program product comprising computer readable instructions executable when running on a system according to any of the embodiments of the present invention to cause a set of one or several processors of the system to perform the steps of any of the aspects or embodiments of the method described herein.

[0157] It should be noted that, unless the context requires otherwise, references herein to objects, features, regions, etc. associated with tiles or tile data structures, etc., should be understood to refer to data indicating these. The data may indicate related items in any manner, and may indicate the items directly or indirectly. Therefore, any reference to objects, features, regions, tiles, etc. may be replaced by references to data indicating them. It should also be noted that the phrases "associated with" or "representing" should not be interpreted as requiring any specific restrictions on the location of data storage. The phrases only require that the features have identifiable relevance.

[0158] The present invention may be implemented with respect to navigable networks including any type of navigable elements and digital maps representing such networks. Preferably, the navigable elements are road elements (of a road network). Although the exemplary embodiments relate to road elements of a road network, it will be appreciated that the present invention is applicable to any form of navigable elements, and digital maps representing such elements, including elements of paths, rivers, canals, cycle paths, tow paths, railway lines, etc. For ease of reference, these are generally referred to as road elements of a road network.

[0159] Various features of embodiments of the invention are described in more detail below. BRIEF DESCRIPTION OF THE DRAWINGS

[0160] Various embodiments of the technology described herein will now be described, by way of example only, and with reference to the accompanying drawings, in which:

[0161] Figure 1 A positioning module is described for determining the absolute position of the device from a global navigation satellite system (GNSS);

[0162] Figure 2 A positioning module is described for determining the relative position of a device within a digital map;

[0163] Figure 3 illustrate tectonic shifts on a global map;

[0164] Figure 4 Demonstrate the impact of such tectonic shifts on digital map data;

[0165] Figure 5 Displays displacement of the position of a location as a function of time (period) due to crustal dynamics;

[0166] Fig. 6A A network showing reference localizations, each with a displacement vector for a given period;

[0167] Figure 6B shows five reference locations with corresponding displacements at period e;

[0168] Figure 7 Describing techniques that can be used to determine displacements at points in a triangle whose vertices correspond to reference locations;

[0169] Figure 8 is a flow chart illustrating one embodiment of a method for determining a displacement at a location p using displacement map data about a reference location corresponding to a vertex of a triangle and compiling a map using this data;

[0170] Fig. 9is a flow chart illustrating one embodiment of a method for determining a displacement at a location p using displacement map data about a reference location corresponding to a vertex of a triangle and using this data to adjust the position of a location of interest when using digital map data;

[0171] Fig.10 is a flow chart illustrating one embodiment of a method for determining a displacement at a location p using displacement map data about a reference location corresponding to a vertex of a triangle and using this data to adjust the position of the location of interest when using digital map data, wherein the displacement data includes displacement velocity data;

[0172] Fig.11 Presenting a server infrastructure for generating a displacement map, and a vehicle environment in which the displacement map data is used;

[0173] Fig.12 An HD map positioning module including a positioning adjustment subsystem according to one embodiment is described;

[0174] Fig.13A An HD map positioning module including a positioning adjustment subsystem is shown according to another embodiment in which the module operates on HD map objects;

[0175] Fig. 13B Instructions for use Fig.13A An exemplary method of an HD map positioning module;

[0176] Fig.14 presenting an embodiment in which positioning adjustments are performed relative to retrieved HD map information;

[0177] Fig.15 Description: Used to export displacement map data for use with tile-based maps. Figure 1 an instance of a method to be used;

[0178] and Fig.16 Description: Used to export displacement maps for use with patch-based maps. Figure 1 Another example of a method used together.

[0179] The same reference symbols will be used for the same elements in the drawings where appropriate. DETAILED DESCRIPTION

[0180] The present disclosure is generally directed to providing improved techniques for processing positioning data. In particular, preferred embodiments are directed to methods of processing positioning data to be used in advanced / autonomous driving applications. However, it should be appreciated that the techniques described herein are not limited to such applications. Thus, while various embodiments will now be described with reference to advanced / autonomous driving applications, it should be appreciated that the present disclosure is not limited thereto and may also find utility in a variety of other applications where high accuracy map functionality may be desired.

[0181] Advanced driving applications in vehicles need to accurately and reliably determine and maintain their position in the real world. This process, often referred to as "localization", relies on one or more localization modules. As described above, localization is often performed using various techniques. For example, GPS measurements are used to provide the position of the vehicle, which can then be matched to a digital map. In order to more reliably determine the position of the vehicle within the map and to determine the orientation of the vehicle, sensor data, especially in the form of image data acquired by the vehicle, is also used. Sensor data indicating objects in the vicinity of the vehicle is often acquired, and then the objects are matched to map objects. This process is called "map matching". In this way, the position of the map object can be determined using the map data and used to determine the real-world position of the vehicle.

[0182] Therefore, such positioning technologies rely on highly accurate map data. Producing digital maps is an expensive and complex process in terms of time and cost. Digital maps are typically compiled using a variety of data sources, including sensor data obtained from mobile mapping vehicles, navigation applications, aerial data, crowdsourced data, website data, etc. In view of this, it is not practical or economical to frequently update digital maps. However, as mentioned above, the dynamics of the earth's crust will cause the absolute position of geospatial features to change over time. This means that over time, digital map data will no longer accurately represent the real-world location of the object. Therefore, this can introduce errors or inconsistencies in the map matching process using digital map data, which can have serious (e.g., fatal) consequences when this information is used for advanced / autonomous driving purposes.

[0183] Therefore, the accuracy of positioning must take into account the dynamics of the Earth's crust to be sustainable. Plate motion is the main factor in the dynamics of the Earth's crust and is associated with slow, steady displacements away from plate boundaries (e.g., 62 to 70 mm / year for the Australian Plate) and sudden (sometimes large) displacements at transform plate boundaries. The latter are often associated with earthquakes. Figure 3 Demonstrating the movement of the Earth's crust on a global map.

[0184] Figure 3A map of the Earth is shown showing the land and ocean masses and tectonic plates in the Earth's crust. As indicated in the figure, each tectonic plate has its own movement, with different speeds and directions. At tectonic plate boundaries, plate collisions and deformations are often associated with earthquakes and other crustal dynamic phenomena. The figure shows the large north-northeast (NNE) displacement of the Australian Plate (lower right corner). Even though the displacement in the Northern Hemisphere is slightly smaller, the annual displacement can be of the same order of magnitude as the required positioning accuracy.

[0185] The positioning method based on HD map data (see description above) determines the positioning of (for example) a vehicle based on the positioning of map objects (i.e., object descriptions in the HD map information). The map objects used may be map objects to which objects detected by the vehicle system in the vicinity of the vehicle have been matched. Due to the shifting of tectonic plates and the associated crustal dynamics, the positions of map objects in the HD map information will not accurately reflect the actual situation over time unless the effects of crustal dynamics are taken into account. If the effects of crustal dynamics are not taken into account, the ability to reliably match detected objects with map objects will be lost over time. This is particularly important in Figure 4 In the argument.

[0186] Figure 4 1 and 2. A portion of an HD digital map showing a portion of a road network near an intersection between road segments and traversed by vehicle 104 is illustrated. Map information at the time of map generation (defined in this exemplary embodiment as a "map epoch") is map ) in the solid line 96.

[0187] At a later time when positioning is performed (called positioning period e loc ) is shown in dashed line 98. Here it can be seen that the map information has shifted due to crustal dynamics. For example, position X1 on road segment 100 has shifted to position X2. Position Y1 of vehicle 104 has shifted to position Y2. Therefore, if the map data is not updated to compensate for crustal dynamics, then as illustrated by shifting the map data from solid line data to dashed line data, attempting to map match an object detected at position X2 at the time of positioning will fail because according to the map data, the object is at position X1. Therefore, not taking into account the effects of crustal dynamics can create conflicts between HD map positioning and other (different) positioning technologies, and can create conflicts between HD map information and outputs from other different positioning technologies.

[0188] Compensate for crustal dynamics and provide Figure 4 One approach to providing updated map information displayed in a map is to copy and deliver the entire map regularly (e.g., once a month or two months). However, the resulting production and delivery costs would be unacceptable, or at least undesirable.

[0189] Some exemplary embodiments of the invention will now be described.

[0190] HD map information is generated from geospatial sensor data and high-accuracy positioning information. For example, geospatial sensor data can be obtained using a mobile mapping vehicle equipped with a lidar sensor, a 360-degree camera, and similar geospatial sensors. In this example, the mobile mapping vehicle includes one or more advanced and accurate positioning sensors that associate accurate positioning information with the sensor data. In addition, the acquisition period is e acq Associated with sensor data. The map compiler uses the sensor data, associated positioning data and acquisition time data to generate HD map information.

[0191] During the HD map generation period, HD map information can be shared with public maps. map associated. A map epoch is a reference time so that the map represents the situation at that time. In some embodiments of the present invention, the map epoch is typically a standard time, which is selected so that multiple maps can share the same epoch, i.e., a common map epoch. Therefore, when sensor data about a particular moment (acquisition epoch) is obtained, the sensor data is typically adjusted (i.e., shifted backward in time) when compiling the map so that the resulting map reflects the situation at an earlier map epoch. This may be performed, at least in part, by a mobile mapping vehicle. Therefore, the compiler may set a map epoch that corresponds to a desired earlier map epoch. Thus, if Figure 4 In an exemplary embodiment of the present invention, the map period may not necessarily correspond to the actual generation time of the map.

[0192] The vehicle is in the positioning period loc Use HD map information for positioning. Positioning period, map period and acquisition period are usually all different. Figure 5 The displacement vector d of the position p is shown as a function of the period e.

[0193] Figure 5 The displacement d of the position of location p as a function of period e (time) due to crustal dynamics is shown. The displacement d at a given period e (i.e., time) is the difference between the position (i.e., the coordinates of location p at period e) and the position (i.e., the coordinates of location p at a reference period). In the figure, the reference period is e acq , but this can be a different period. In the figure, e acq With e map The displacement between is ΔG, and e map With e loc The displacement between them is ΔL.

[0194] Figure 5 Also shows the period introduced earlier (e acq 、e map 、eloc ) and the displacement values ​​of the position of the location p at these times. The figure shows the displacement d as a one-dimensional value. In reality, the displacement vector is a two-dimensional or three-dimensional vector.

[0195] According to the present embodiment, a displacement map is provided that can be maintained and updated independently of the HD map information. When using the HD map information, this displacement map is able to adjust the position of the positioning to compensate for the effects of crustal dynamics. Therefore, the displacement map is able to take into account such effects without the need to update the entire HD map. In fact, the displacement map can be integrated with the HD map as a displacement map layer. However, the displacement map can alternatively be provided as a separate map.

[0196] Displacement determination

[0197] Certain exemplary methods that may be used to generate displacement maps will now be described.

[0198] The displacement of any position p is determined based on the position information of several reference fixes. These reference fixes (reference points) are chosen to form an irregular triangular network covering the map area of ​​interest (or the entire Earth). A reference fix can be any point at which an accurate displacement can be measured or modeled. Typically, these points will be fixes where permanent GNSS receivers are installed, such as the Continuously Operating Reference Stations (CORS) in the United States, or Fig. 6A A reference station operated by an RTK (Real Time Kinematics) service provider is shown in Figure 2.

[0199] Fig. 6A A network of reference fixes 150 with displacements d in the form of vectors for a given time (i.e., epoch e) is shown. The reference fixes 150 define vertices of triangles, such as triangles 152, 154, 156, etc. The displacements indicate the change in position of a fix between a first and second time or epoch corresponding to a reference epoch (e.g., a map epoch) and a subsequent epoch e. ​​The epoch e may be any epoch of interest, such as the current or fix time. The density of reference fixes in the network may be small (i.e., to define large triangles) in regions of less crustal activity (e.g., in the center of a large tectonic plate) and large (i.e., to define small triangles) in regions of more crustal activity (e.g., at a plate boundary).

[0200] Figure 6BFive reference locations r (r1, r2, r3, r4, r5) are shown, each with a displacement d (d1, d2, d3, d4, d5) for period e. The five reference locations form three triangles T (T1, T2, T3) with the reference locations as vertices. In the figure, triangle T1 is formed by reference locations (r1, r2, r3), triangle T2 is formed by reference locations (r1, r3, r4), and triangle T3 is formed by reference locations (r4, r3, r5). At period e, reference location r has a displacement d relative to location r at reference period e0. This can be captured by storing a tuple (r, d, e), e0, and the coordinate r of e0. Alternatively, the displacement of reference location r at e0 can be described by a tuple (d, e). Similarly, the displacement can be tracked by a tuple (r, R, e), where R is the actual location of reference location r at period e. All of these variables are able to produce a displacement d of reference location r at period e. Displacement values ​​are given relative to any suitable reference frame (eg, the International Terrestrial Reference Frame).

[0201] For N reference locations RL = {r i Each reference position r in the set RL |i=0...N} i , K tuples P of displacements of reference locations attributable to crustal dynamics can be determined i ={(i,d j ,e j )|j=1…K} i To determine the displacement d of the reference position r at time e, search the set P i A tuple of , where e j Equal to and corresponding to the displacement d j Then the determined displacement d is formed. If there is no matching value of e in the tuple of Pi, then two close epochs e are obtained from the set a and e b (So, e a <e<e b And P i Does not fall in period e b With e a The period between j ). The displacement d of the reference location r can then be interpolated, for example, using the following.

[0202]

[0203] Other interpolation techniques (eg, high order polynomials, splines) may also be used.Determining the displacement d of a reference location r at an epoch e may be adapted to different data formats for recording the displacement of the reference location at different epochs.

[0204] The displacement of the reference location may be used to estimate the displacement of the general location of the triangle relative to the reference location (ie, the change in position of the location between epochs). Figure 7 Demonstrates the use of barycentric coordinates to estimate (using interpolation) the displacement of a position within a triangle of a reference position.

[0205] The displacement of any point in the triangle is a linear combination of the displacements at the vertices. For example, the displacement value of the middle of the top edge is 1 / 2 times the value of the left vertex, 0 times the value of the bottom vertex, and 1 / 2 times the value of the right vertex.

[0206] Each position in a triangle with vertices (r1, r2, r3) can be expressed as a tuple (λ1, λ2, λ3) where 0 < λ i <1 and λ1+λ2+λ3=1, as in Figure 7 . The point in the middle of the top edge can be expressed as (0.5, 0, 0.5). The displacement of the location can then be calculated using the displacement vector of each vertex and the barycentric coordinates of the location using λ1*d1+λ2*d2+λ3*d3. Since the HD map location p can be encoded in different coordinate systems, the HD map location p may need to be converted to the barycentric coordinates of the triangle containing the location p. Techniques that can be used to provide such conversions are known in the art. After the conversion, the barycentric coordinates and the displacement at the vertex (defined by the three reference locations) are able to determine a tuple (d, p, e), which includes the interpolated displacement d of the HD map location p at epoch e. ​​The coordinate transformation can also be used to determine whether the HD map location p is within the region of the triangle, because all barycentric coordinates (λ1, λ2, λ3) of the location inside the triangle have the property (for all i=1,2,3, 0<λ i <1).

[0207] HD map generation - compensates for displacement since sensor data acquisition time

[0208] In some exemplary embodiments, the present invention may provide a map compiler that uses acquisition periods associated with sensor data collected for HD map creation. acq , and the acquisition represents the acquisition period and the map period e map The displacement information of the crustal dynamics between the HD map objects is used to adjust the coordinates of the HD map objects to the HD map period. map Therefore, the HD map compiler generates coordinates representing HD map objects and maps at map time. map This map generation method compensates for crustal dynamics during different acquisition periods associated with sensor data collected for HD map creation and generation periods associated with compiled / generated HD map information.

[0209] refer to Figure 8In step 1, the method comprises obtaining an indication of an acquisition period e associated with sensor data collected for HD map creation. acq With map period map The displacement map data of each of the plurality of reference fixes between the time periods (i.e., the position change) of the reference fixes. In this example, the map period corresponds to the map generation period, rather than the earlier reference period, although such an arrangement is contemplated as described below. In this example, the reference fixes are based on the displacement (i.e., the position change) of each of the plurality of reference fixes between the time periods. Figure 6B Define a set of triangle vertices as described in .

[0210] HD map compiler uses the acq The sensor data obtained from positioning p is used to generate the map at epoch e map The HD map object data of the location p. The location p can be determined from the map acquisition period e as follows acq To the map generation period map The displacement d.

[0211] In step 3, for a location p, obtain the triangle T containing p. For each reference location r at the vertex of T, determine the reference location r from the map acquisition time e acq To the map generation period map The displacement d (i.e., change in position) of the map (step 5). The centroid interpolation (described above) can then be used to determine the position p from the map acquisition period e acq To the map generation period map The HD map compiler uses this displacement d to adjust the position of the HD road object's location in the HD map information in step 9. This may involve shifting the coordinates or (in general) the location of the road object, which may be defined by an extended location rather than a point location.

[0212] Therefore, the HD map compiler can correct the HD map information to correct the map This method can adjust for differences in sensor data acquisition periods used to generate HD map information.

[0213] In a variant, the sensor data may determine its position relative to a reference position (eg, an RTK station) and then be mapped during the mapping period. mapThe position associated with the sensor data is adjusted to the position of the reference position. This may be performed, for example, by a mobile mapping vehicle. In these embodiments, the map epoch may be an earlier reference time, rather than the time at which the map was generated. This simplifies map generation because all sensor data is associated with a position at the reference map epoch. The compiler is then not required to shift any sensor data to compensate for the displacement between the acquisition of the data and the time at which the map was generated. The adjusted sensor data may simply be used to provide a map that reflects the position corresponding to the map epoch. map A map of the situation at the reference time.

[0214] For example, as illustrated in the above examples, it will be appreciated that the map epoch may or may not correspond to the actual time at which the map was generated, since when the map is generated, the sensor data or other data used to compile the map may be adjusted to reflect the situation at the reference time. This may enable the generation of multiple maps that share the same epoch, helping to ensure compatibility between maps and facilitating the use of the displacement maps of the present invention. This may be achieved, for example, by shifting the sensor data obtained by a mapping vehicle back in time to the desired standard map epoch. It is further noted that the map epoch need not necessarily be a common value for the entire map. Therefore, references here to the map epoch or map generation time refer to the relevant epoch or time with respect to at least the portion of the map under consideration (i.e., the portion covering the location of interest).

[0215] Displacement map generation - displacement since map period

[0216] It is desirable that the HD map information remain constant over a relatively long period of time, as this reduces map generation and map distribution resources. Preferably, the core HD map information remains constant over a number of years. As described above, if the HD map (generation) period e map and positioning period loc Too far apart, then crustal dynamics can cause inconsistencies and failures in the positioning process. In the described examples, the map period may be referred to as the map generation period. However, it should be understood that this may correspond to the actual generation time of the map, or an earlier reference time used in generating the map as described above.

[0217] Frequently updating maps to new periods is not an attractive solution to this problem because it involves considerable costs to generate HD maps and distribute new versions of HD maps. Instead, in some exemplary embodiments of the present invention, a map server creates a separate map or separate map layer containing displacement information. As described above, the displacement information indicates changes in position at a location (e.g., a reference positioning network) that occurs between different times (e.g., between particular periods of interest) due to crustal dynamics. Thus, the present invention enables HD maps that include large amounts of data (including geographic coordinates) to be maintained for many years in the same period, while still being able to use sensor data acquired at a later time to perform functions (e.g., positioning). This substantially reduces map compilation and HD map distribution costs.

[0218] We will now describe a method for providing map clients and HD map applications with support for converting HD maps from map generation time periods to map Transform to the (later) displacement period e dis Various technologies for accessing displacement map data of HD maps. Displacement period dis is the period of map generation map A displacement period may correspond to or be sufficiently close to any period of interest at which it is desired to update the HD map data in order to perform functions using the data. In an exemplary embodiment in which the HD map data is used during positioning, the displacement period is sufficiently close to the positioning period used in the vehicle. loc , making the crustal dynamics between these two periods negligible.

[0219] A displacement map contains data indicating a plurality of reference locations, each of which is associated with displacement information. The nature of the dynamics of the Earth's crust causes displacements to be similar over larger map areas. This can create a relatively efficient encoding of displacement information. Displacement refers to the change in position of a location (e.g., a reference location) between times of interest (e.g., periods).

[0220] The first option is to use a relatively sparse network of reference locations and their displacements from the map generation phase to the displacement phase. As described above, in some preferred embodiments, the network of reference locations defines triangles T, where the reference locations are at the vertices. The triangles are tessellated triangles. Each reference location has a displacement from e map To e dis The associated displacement (position change) that occurs. The advantage of using tessellated triangles to encode displacements is that the edges between different triangles are continuous.

[0221] As an example, use a pair of three triangles Figure 6BIn the example, the displacement map contains three triangles (T1, T2, T3). The displacement map then contains the information: (T1, r1, r2, r3), (T2, r1, r3, r4), (T3, r4, r3, r5), (r1, d1), (r2, d2), (r3, d3), (r4, d4), (r5, d5), e map 、e dis Therefore, the displacement map contains the indication e map With e dis The displacement data between the vertices of triangle T. Note that e map It can also be associated with a triangle. However, this is optional. dis This can be indicated using a displacement map version number.

[0222] Reference now Fig. 9 Flowchart of, in an exemplary embodiment using this data, the method comprises receiving an indication of a location p of interest - step 10. This is a location relative to a map. In step 12, the method comprises, for the location p of interest, determining a displacement d of the location p of interest by searching the displacement map data to find a triangle T covering the location p. In step 14, the method involves transforming the location p to the barycentric coordinates of the triangle T. The determination step may cache the results of locating and matching triangles for use in speeding up future triangle searches. The barycentric coordinates of the vertices of triangle T and the displacement are then used to calculate e map With e dis =The displacement d of the location p between e and p is calculated - step 18. Since the triangles are relatively large and the displacement only changes slowly over these triangles, these steps may be performed infrequently, or previous results may be used to speed up the displacement determination of locations that are not much different from previous locations. In step 20, the determined displacement d of the location p is used to adjust the position of the location p of interest to compensate for the displacement in e. map With e dis The displacement d that has occurred is attributed to the dynamics of the Earth's crust.

[0223] The displacement map can be used for streaming HD map delivery services, as well as delivering HD map content on storage media or downloading HD map content as HD map content files. In these methods, the displacement map is a separate map that can be used by a map application.

[0224] Displacement velocity diagram

[0225] In other embodiments, a displacement map is obtained that includes data indicating the velocity of displacement at each reference location, rather than indicating the displacement, ie, the change in position of the location between different times (eg, periods of interest).

[0226] Therefore, although in the above described embodiment, the displacement d indicates that a The location of the positioning a and in period e b The location of the positioning b The displacement velocity describes the linear variation of the positioning p which can be obtained by the formula

[0227]

[0228] (Equation 2)

[0229] The velocity can be used, for example, by using the formula: d' = v*(ee a ) determines the displacement d' at any period of interest e. This indicates that the displacement can be determined at any of a series of times (i.e., periods and starting periods (i.e., times) based on the localized displacement velocity values ​​obtained from the displacement map). The displacement velocity values ​​can be compared between the period of interest (e.g., the current time) and the reference starting time e at which the displacement is desired to be determined. a It should be clear that v can be a constant rate, or a more complex expression.

[0230] In some cases, the displacement velocity can be used using the formula: d' = d0 + v* (ee a ) describes the first period e a There is a change in the base displacement d0.

[0231] Displacement maps that include displacement velocity data are useful for determining displacement for a series of periods, as compared to a single period of a displacement map that includes only displacement distance data. In addition to the position of a fix (e.g., a map fix) at a given (e.g., earlier) period, a displacement velocity map also requires knowledge of the period value (i.e., the period for which it is desired to determine the position of the fix of interest (e.g., a map fix)) in order to determine the displacement of that fix.

[0232] Using the example of the displacement map from the previous paragraph, the displacement velocity map of the example can be expressed as;

[0233] (T1,r1,r2,r3), (T2,r1,r3,r4), (T3,r4,r3,r5), (r1,v1), (r2,v2), (r3,v3), (r4,v4), (r5,v5), e map

[0234] Using this displacement velocity diagram information, d2 = v2*(e dis -e map )Get in e disThe displacement of r2 is d2.

[0235] refer to Fig.10 , a method of using displacement velocity data to determine the displacement of a location of interest may include;

[0236] The received map corresponds to the map period e map An indication of the location of interest p of the location of the location - step 24.

[0237] Search the displacement map data to find triangle T covering position p - step 26

[0238] Transform position p to the barycentric coordinates of triangle T - step 28

[0239] Use the displacement velocity data associated with the vertices of triangle T to determine e map With e dis The displacement of each vertex between - step 30;

[0240] Calculate e using the barycentric coordinates of the vertices of triangle T and the determined displacement map With e dis Positioning p between displacement d-step 32

[0241] The determined displacement d of the location p is used to adjust the position of the location p of interest to compensate for the displacement d that has occurred due to crustal dynamics—step 34 .

[0242] Of course, the method may be performed in other ways, for example, by determining the displacement speed of position p by determining the displacement speed associated with each vertex, and thus determining the displacement of p between relevant times, etc.

[0243] Other variants may use other interpolation techniques (eg Kriging) for estimating the displacement of a position that varies as a function of time. It should be clear that different interpolation techniques require different parameters for determining the displacement.

[0244] Overview

[0245] The present invention provides a method for generating a displacement map and a method for adjusting positioning data using the displacement map data. Fig.11 A functional diagram of an exemplary system for generating displacement map data and adjusting position data using the displacement map data is shown in FIG.

[0246] Fig.11 A server infrastructure for generating a displacement map and a vehicle environment in which the displacement map data is used to adjust a map position from a map coordinate system (i.e., a first reference system) to a vehicle coordinate system (i.e., a second reference system) are presented. Position adjustment can also be applied in the reverse direction. Various embodiments of the invention are presented in more detail below.

[0247] The displacement map server (for example) generates displacement map data according to any of the described embodiments. The displacement map data is generated based on the HD map data, the reference positioning data and the reference positioning information. The reference positioning information indicates the displacement of the reference positioning between different times, for example, in terms of position change or displacement speed as described above. The different times include at least a map period corresponding to the reference time associated with the map and a current period (i.e., the current time). Therefore, the displacement map data includes displacement map data that provides information indicating the displacement of the reference positioning between the map period and the current time. This can be achieved in various ways. For example, in a simple embodiment, the displacement map data includes a displacement speed for each reference positioning, which can be used to determine the displacement of each reference positioning relative to the map period at any given time of interest (i.e., the current time) based on the difference between the current time and the map period.

[0248] The position adjustment subsystem can transform the position of the position relative to the map coordinate system at any given period (time) to the position relative to the vehicle coordinate system at that period (and vice versa) in a manner that compensates for changes in the position of the position that have occurred between the current time (e.g., the time of the position fix) and the map period due to crustal dynamics.

[0249] Use sensor data, HD maps and displacement maps for localization

[0250] An embodiment of the present invention will now be described with respect to a situation in which the present invention is used to determine a displacement for adjusting a position of a positioning for use with HD map data in a method comprising; acquiring a first positioning, using the first positioning to obtain displacement map data and processing the displacement map data to produce a displacement associated with the first positioning.

[0251] In one embodiment of the present invention, a method for providing absolute positioning based on vehicle sensor data and HD map data is provided. The functional diagram of the method is as follows Fig.12 Displayed in.

[0252] Fig.12 An HD map positioning module with an additional positioning adjustment subsystem for implementing the techniques of the present invention is shown. The positioning adjustment subsystem obtains displacement map data from a displacement map server.

[0253] The object detection subsystem of the positioning module receives sensor data from sensors associated with the vehicle. In this exemplary embodiment, the object data used by the positioning module is in a map reference system (previously converted from the vehicle system) so that it can be used directly in the map matching process, although other arrangements can be used. The object data is provided to the map matching subsystem of the positioning module. The map matching subsystem uses the detected object data and the HD map data to match the detected object with the map object. This provides a map object corresponding to the detected object in the map reference system. The position of this map object is then provided to the positioning adjustment subsystem. The positioning adjustment subsystem uses the displacement map data to adjust the determined positioning of the object based on the displacement of the object position between these times / periods according to the effects of crustal dynamics that have occurred between the current (i.e., positioning) time / period and the map period. If the displacement map data does not contain data for the exact current / positioning period, then the most recent period in the available data will be used, for example, the latest version of the displacement map data (given that crustal dynamic changes tend to be small relative to time, the data should generally be sufficiently close to the current displacement). If displacement speed is used, then this can more easily enable the displacement of any current / positioning time to be obtained and used. The adjusted positioning is provided to the vehicle.

[0254] In this way, a position of the detected object in the vehicle reference frame is provided, which takes into account the effects of crustal dynamics. This adjusted position is output and is used to determine the position of the vehicle. The position adjustment subsystem may also output data indicating the period to which the position has been adjusted.

[0255] The localization module thus uses the localization and displacement map data from the map object matching subsystem to adjust the localization to provide an absolute localization, which is output for determining the localization of the vehicle. Absolute localization is localization according to a common reference system used in the vehicle, for example as described in ITRF2014.

[0256] In a variant, the HD map positioning module operates on HD map objects, such as Fig.13A In these embodiments, Fig.12In embodiments of the present invention, vehicle sensor data is input to the object detection subsystem. In these embodiments, the positioning adjustment subsystem acts on the HD map data itself, rather than performing adjustments to compensate for the effects of crustal dynamics once the object has been map matched and position transformed to the vehicle reference frame. The HD map data is input to the positioning adjustment subsystem, and the displacement map data is accessed and used with the HD map data to provide adjusted HD map data for input to the map object matching subsystem. The adjusted HD map data is one in which the positions of map objects according to the initial HD map data have been shifted using the displacement map data to account for changes in the positions of map objects due to crustal dynamics that occurred between the map period and the current time (e.g., the positioning time). Therefore, the HD map data can be considered to have been shifted from an initial first reference frame to a second adjusted reference frame. The positioning adjustment subsystem can output the period at which the adjustment has been performed.

[0257] Map matching of the object may then be performed relative to the adjusted HD map data. The determined position of the localization of the object determined according to the adjusted HD map data provides the position of the object that has been adjusted for the effects of crustal dynamics. In this way, by first adjusting the HD map data itself, map matching of multiple objects for a particular period (e.g., a localization period) may be performed more efficiently, rather than requiring adjustment of the localization of detected objects on an object-by-object basis.

[0258] Now we will refer to Fig. 13B To describe the use Fig.13A An embodiment of a method for positioning a module.

[0259] In step 40, the positions of map objects are determined based on the HD map data in the initial map reference frame.

[0260] In step 42, the displacement of each fix from the map epoch to a later fix epoch is determined.

[0261] In step 44, the position of the map object providing the map data is adjusted to provide the map data in the updated map reference system.

[0262] In step 46, data indicative of a detected object is received.

[0263] In step 48 , map objects are detected that correspond to objects detected using the adjusted map data.

[0264] In step 50 , the position of the map object according to the adjusted map data is output.

[0265] In yet another variation, the positioning adjustment may be performed relative to the retrieved HD map information (e.g., map objects). Fig.14 Shown in more detail.

[0266] Fig.14 An HD map client associated with a vehicle is shown. The HD map client receives a request for an HD map object from an HD map application in the computing infrastructure of the vehicle (not shown). The HD map client processes the request as it should, retrieving the relevant HD map data and extracting the requested HD map object. However, the map object is then provided to a positioning adjustment subsystem. The positioning adjustment subsystem receives the map object and adjusts the position (e.g., coordinates) of the object to a common coordinate system used in the vehicle. Thus, the position of the map object is transformed from the map reference system to the vehicle reference system. However, this transformation is performed in a manner that adjusts for the effects of crustal dynamics. The positioning adjustment subsystem determines the displacement of the position (i.e., coordinates) of the map object using the displacement map data and provides as output the adjusted position of the map object in the reference system of the vehicle system.

[0267] The positioning adjustment subsystem may associate data indicative of the displacement of the map object with the data indicative of the map object for optional use by the HD map application.

[0268] HD map updates after major map releases

[0269] Although embodiments have been described with particular reference to situations in which positions are adjusted from a map generation period to a later positioning period, the invention is equally applicable to other period adjustments in either direction, such as adjustments from a later period to an earlier map generation period. For example, in some cases, an HD map compiler may need to provide updates to a relatively small portion of a map area or detectable geospatial objects due to changes in a road network. This may require the map compiler to generate a displacement from a later acquisition period to an earlier map (generation) period in order to avoid recompiling the entire HD map. In some embodiments, displacement map data is used to determine the position displacement of a sensed object from a later acquisition period to an earlier map generation period.

[0270] Tile-based displacement (displacement based on tiles instead of global maps)

[0271] According to the present invention, in any one of its aspects or embodiments, a digital map using the technology may include multiple levels (or layers), each of which is divided into multiple tiles in the above-mentioned manner. That is, the tiles may be arranged into multiple corresponding levels, and each map tile may therefore contain object information of its associated map level. For example, different levels of a map may be used to store different types of object data. Therefore, each map level may contain a subset of available map information. For example, a reference level of a map may contain contact road geometry information (e.g., a set of arcs and nodes defining a navigable (e.g., road) network). Different types of objects and / or attributes may then be stored in progressively higher levels in the map. This structure advantageously allows map-based applications that require map data to extract map data from any level, so that relevant information (only) for map-based applications may be extracted based on what information the application needs.

[0272] The present invention can be used in the context of the generation and provision of digital map data in general. In particular, the present invention can be used in conjunction with the provision of high-definition digital map data. It should be understood that such maps are typically complex data structures, containing roads, road lanes, intersections, traffic information, points of interest, and many other types of information. Therefore, in order to reduce the amount of data that must be stored locally to a vehicle running a map-based application and / or to reduce the bandwidth required to send map data to the vehicle, the entire area represented by the digital map (and in some embodiments of the present invention) can be divided into a plurality of smaller areas for the purpose of data storage, so that the device only needs to retrieve data related to the area related to its current position and / or predicted travel path. In the present invention, the smaller areas into which the entire area is divided for mapping purposes are referred to as "tiles". However, it should be understood that other equivalent terms can be used, and the term "tile" does not mean any particular limitation on the shape or size of the area into which the digital map is divided.

[0273] Using this tile-based approach can help provide more efficient transmission and distribution of map data from various map data sources to vehicles that need the map data. For example, an advantage of the tile-based approach is that map data from different sources can be easily compiled into a set of corresponding tiles at a server (or multiple servers), and then the relevant map data can be delivered or provided, for example, tile by tile, to vehicles that need map data for the area covered by the tile. The tile data structure can then be decompressed, for example, by an appropriate client application (interface) executed on one or more processors onboard the vehicle, in order to extract the required (map) object data, which can then be distributed as needed to various map-based applications running in the in-vehicle environment.

[0274] Of course, it is not necessary to use a patch-based approach.

[0275] In some embodiments, the displacement map may be delivered in a displacement map layer. In one such embodiment, a map tile contains displacement triangles associated with the map tile. In one such embodiment, Fig.15 In the description.

[0276] Fig.15 Shows a displacement map with 6 triangles and 4 map tiles. The tiles and triangles are of similar size. Map tile M x,y+1 All six triangles need to be referenced, M x+1,y+1 Only three triangles are needed.

[0277] For larger triangles, the situation is different, such as Fig.16 Displayed in.

[0278] Fig.16 A large triangle T is shown that spans a number of map tiles M. In this case, the map tiles Mx,y only contain information for triangle T.

[0279] Fig.16 The example shows triangles that are substantially larger than map tiles. Therefore, a variant implementation may associate a single displacement value (e.g., a vector) with the map tiles of the HD map layer. A single displacement value may then be assigned to each of these map tiles. However, this variant may distribute the displacements as a grid. Typically, since the displacements are usually similar for relatively close cells, compression techniques (run-length encoding, image compression, DCT encoding, etc.) can be used to efficiently encode this displacement map. This variant may also be used to deliver displacement velocity maps or other types of displacement interpolation maps. The parameters of these variant maps may be encoded and distributed as a grid (representing a collection of small map tiles).

[0280] It will be appreciated that different formats of displacement map data may be used depending on the context of the data required and system performance, etc. Variants using map tiles may not provide such efficient encoding compared to a separate displacement map using only triangle encoding, but may provide other advantages in certain contexts.

[0281] For the purpose of illustration and description, the above specific embodiments have been presented. It is not intended to be exhaustive or to limit the technology described herein to the precise form disclosed. In view of the above teachings, numerous modifications and variations are possible. The described embodiments are selected in order to best explain the principles of the technology described herein and its practical application, thereby enabling other technical personnel in the field to best utilize the technology described herein in various embodiments and with various modifications suitable for the specific purposes envisioned. Therefore, the features disclosed in this specification, drawings and / or claims may be materials for implementing various embodiments taken individually or in various combinations thereof. In addition, although the present invention has been described with reference to various embodiments, it should be understood by those skilled in the art that various changes in form and details may be made without departing from the scope of the invention set forth in the appended claims.

Claims

1. A method of transforming the position of one or more locations of interest from a first reference system defined by a first coordinate system to a second reference system defined by a second coordinate system, wherein the first reference system is a reference system defined relative to a representation provided by a digital map covering a geographical area containing the locations of interest, the digital map comprising a plurality of segments connected by nodes, the segments representing elements of a navigable network in the geographical area covered by the digital map, wherein the positions of the locations of interest relative to the first reference system are positions relative to the digital map, and wherein the second reference system is a reference system defined relative to the real world and is common to all systems of a vehicle traversing a path of the navigable network; The method comprises, for the or each location of interest: obtaining data indicative of the position of the location of interest relative to the first reference system; obtaining displacement map data, the displacement map data comprising, for each of the one or more locations, data indicative of changes in the absolute position of the location relative to the earth's surface that occur over time due to crustal dynamics; and determining data indicative of the position of the location of interest relative to the second reference system using the obtained data indicative of the position of the location of interest relative to the first reference system and the displacement map data; in, The step of using said acquired data comprises using said displacement map data to adjust the position of said location of interest when transforming said position of said location of interest from said first reference system to said second reference system to compensate for changes in the corresponding absolute position of said location of interest relative to said earth's surface that are expected to have occurred due to crustal dynamics since said digital map was generated; And wherein the method further comprises generating for output data indicative of the determined position of the location of interest relative to the second reference system.

2. A method according to claim 1, comprising transforming the position of the location of interest relative to the first reference system to a position relative to the second reference system, and then using the displacement map data to adjust the position of the location of interest relative to the second reference system to compensate for changes in the corresponding position of the location of interest relative to the earth's surface that are expected to occur due to crustal dynamics since the digital map was generated.

3. The method according to claim 1, wherein the method comprises: The displacement map data is used to adjust the position of the location of interest relative to the first reference system to compensate for changes in the corresponding position of the location of interest relative to the earth's surface that are expected to have occurred due to crustal dynamics since the digital map was generated, and then the adjusted position of the location of interest relative to the first reference system is transformed into a position relative to the second reference system. The method of claim 1 , wherein the locations of interest are the locations of objects encountered by the vehicle while traversing a path of the navigable network. The method of claim 1 , wherein the location of interest is a location of a map object requested by the vehicle.

6. The method of claim 5 , further comprising determining displacement data indicative of a change in the absolute position of the position fix that has occurred since the digital map was generated, associating the displacement data with data indicative of the position of the map object in the second reference system, and providing the displacement data together with the data indicative of the position of the map object in the second reference system to the vehicle.

7. The method of claim 1, wherein for each of a plurality of reference fixes, the displacement map data comprises data indicative of a change over time in the absolute position of the reference fix.

8. A method according to claim 1, wherein the method comprises using the displacement map data to determine data indicative of expected changes in the absolute position of the location of interest between times of interest.

9. The method of claim 7, wherein the data indicative of changes in the absolute position of the reference fix over time comprises a set of one or more displacement vectors, each displacement vector indicating a change in the position of the reference fix between different times.

10. The method of claim 1, comprising using a current time and data indicating the position of the location of interest to determine the data indicating an expected change in the absolute position of the location of interest between the times of interest, wherein the times of interest are the time when the map was generated and the current time.

11. The method of claim 1 , comprising obtaining, by an interpolation process based on data indicating changes in absolute position relative to one or more reference locations, data indicating expected changes in the absolute position of the location of interest between the times of interest.

12. The method of claim 1, wherein for each of a plurality of reference fixes, the displacement map data comprises data indicating a displacement of the reference fix between a reference time and one or more subsequent times, wherein the reference time corresponds to a generation time of the digital map.

13. The method according to claim 1, wherein: For each position fix, the displacement map data comprises data indicative of a velocity of the position fix, and the method comprises using the velocity data relating to one or more of the position fixes to determine data indicative of an expected change in absolute position of the position fix of interest between times of interest.

14. The method of claim 1, wherein the displacement map data is provided with respect to positions corresponding to vertices of a set of triangles covering a geographic area.

15. The method of claim 1, wherein the displacement map data is associated with a map tile that includes the location of interest.

16. The method of claim 1, comprising determining a position of a vehicle in the real world using the data indicative of the position of the location of interest in the second reference system.

17. A non-transitory computer-readable storage medium storing software code which, when executed on a processor, performs the method according to any one of the preceding claims.

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