VERSIONING OF DIGITAL STREET MAPS

Description

[0001] The invention relates to a method for versioning digital road maps by means of incremental updates and to a vehicle with a computing unit for carrying out the method.

[0002] Digital road maps are used by vehicles in a variety of ways. For example, digital road maps are used to determine and present navigation routes. Information stored in a digital road map can also be used to control vehicle functions in automated and autonomous vehicles. The greater the degree of automation of the vehicle, the more accurate road map information is required. The information should also be as up-to-date as possible.

[0003] For this purpose, digital road maps are regularly updated. This update is often done via mobile communications. To reduce the amount of data transmitted, so-called differential or incremental updates are often used. In this case, the entire monolithic data set of the digital road map is not replaced, but rather only the differences between the outdated and the current map version are imported.

[0004] The disadvantage, however, is that managing different versions of the digital road map is very time-consuming. Maintaining different map versions can be important for a map manufacturer, as they may want to offer different maps for different customers, for example. There may also be an interest in providing different maps for one and the same geographical area, for example, for different use cases. For this purpose, individual map versions can be duplicated in a so-called "fork" and then continued as a separate map set. This further increases the effort required to manage different map versions, as both map sets must now be maintained. This process is also error-prone, as the increased manual effort also increases the risk that changes to individual map versions are forgotten or incorrectly implemented.

[0005] Furthermore, it is not possible to apply selective changes to different map versions. This means that different versions of the map cannot be combined; changes must be applied one after the other.

[0006] A method for updating a digital map is known from patent application DE 10 2016 219 258 A1. The method disclosed in the document simplifies the implementation of incremental updates of maps available in different versions. Updates for the same map objects for different versions of the map are stored in an update data set. The size of such an update data set is correspondingly large.

[0007] Furthermore, DE 10 2015 206 519 A1 discloses a method for updating digital road maps divided into individual tiles using differential updates. For map tiles to be updated, only those changes are imported that are not yet present in the map tile being updated. Here, too, there is a fixed order in which updates are imported into the digital road map. An arbitrary combination of changes is not possible.

[0008] CN 1 02 607 576 A discloses a method for incrementally updating digital road maps using versioning. Starting from an initial base map, a hash function is applied to the base map. Based on a comparison of hash tables of target and actual versions of the digital road map, map difference packages are provided. However, no direct versioning of the digital road map is disclosed, but rather indirect versioning through versioning of map objects.

[0009] Application DE 10 2004 001 797 A1 also discloses a method for incrementally updating digital road maps using versioning. Map difference packages are provided, which include changes to at least one individual change in a map feature. The application of a hash function to the base map to generate the version hash is not disclosed.

[0010] US 2021 / 0 026 834 A1 discloses a method for verifying software and data updates for vehicles based on blockchain technology. The method applies a hash function to initial data and other stored information and generates dedicated hashes within a Merkle hash tree. The provision of map difference packages and the application of blockchain technology to versioning are not disclosed.

[0011] The present invention is based on the object of providing an improved method for versioning digital road maps by means of incremental updates, which enables the management and use of different versions of the digital road map with comparatively little effort.

[0012] According to the invention, this object is achieved by a method for versioning digital road maps by means of incremental updates with the features of claim 1. Advantageous embodiments and further developments as well as a vehicle with a computing unit emerge from the dependent claims.

[0013] In a method according to the invention for versioning digital road maps by means of incremental updates, the following method steps are carried out according to the invention: Providing a base map; applying a hash function to the base map to generate a version hash of the base map; providing map difference packages, wherein a map difference package comprises at least one individual change to a map feature; versioning the digital road map by forming at least one continuous version chain, starting with the base map, wherein: to generate a current map version, a map difference package to be applied is linked to the map version located before the current map version in the version chain, wherein for this purpose the version hash of the previous map version and the map difference package to be applied are input to the hash function in order to generate a version hash for the current map version.

[0014] The method according to the invention enables the management and use of different map versions in a particularly simple manner. Thus, the method according to the invention reduces the computing effort and memory requirements required to update digital road maps, since incremental updates in the form of map difference packages are used to update the base map stored as a monolithic dataset. Furthermore, managing the maps as a version chain enables particularly high flexibility in updating digital road maps, so that any version of a digital road map can be combined with any map difference packages without much effort.

[0015] The core idea of ​​the invention is the management of the digital road map in the manner of a blockchain. The base map represents the starting block, which is converted into a version chain of different map versions by linking it with map difference packets. Unlike a cryptocurrency such as Bitcoin, however, there is not just a single version chain; rather, any number of version chains can be generated from the base map. Where possible, different map versions can also be combined with each other to form new version chains.

[0016] A link from a current map version to the previous map version is necessary because only the changes are saved for each map version. Each map version is identified by a unique ID in the form of the version hash. This enables particularly easy comparison of the different map versions. Furthermore, linking the individual map versions to form a version chain using hash functions ensures protection against data manipulation. This prevents changes from being tampered with and allows them to be clearly traced. Linking to the previous map version only requires saving the version hash of the previous map version, which reduces the storage requirements of the current map version.

[0017] As already mentioned, the version changes are modular, allowing individual map difference packages to be applied to the base map in any combination. This significantly simplifies the effort required by a map provider to provide different customer-specific map sets. Instead of duplicating the base map and incorporating future changes into both version sets separately, the method according to the invention makes it possible to automatically apply map differences to different version chains.

[0018] With the availability of any map version, the map history is also implicitly available. This means that all map versions are always available with minimal memory requirements. If a specific map version is to be used, the map difference packages required for the respective map version are applied to the base map. This allows you to revert from a faulty digital road map to the last functional map version.

[0019] Calculating the version hash is also possible with comparatively little computational effort. The hash function only considers the version hash of the previous card version and the change to be applied. This requires significantly less computing power than, for example, calculating a hash for a complete monolithic card data set.

[0020] The digital road map can also be divided into individual tiles.

[0021] One or more base maps can be carried in a computing system, and the method according to the invention can be applied to each of the individual base maps. For example, a first base map can correspond to the geographical region of a first country, for example Germany, and a second base map can correspond to a second geographical region, such as France. According to one embodiment of the method according to the invention, which will be discussed later, the digital road maps can be used in a vehicle, whereby, for example, when a person driving a vehicle travels from Germany to France, the base map used for France is updated or enriched when the journey begins according to the method according to the invention.

[0022] The map features are map objects such as individual road sections, intersections and the like and the map object properties valid for these map objects, for example a speed limit valid for the respective map object, hazard warning, geoposition data or the like.

[0023] An advantageous development of the method according to the invention provides that a current map version is only included in the version chain if an authoritative authority releases the current map version. This maintains the integrity of the version chain. For example, a development team can examine the effects of new map difference packages on various map versions and only release those map difference packages for the generation of current map versions for which the corresponding current map version runs stably. This procedure is also referred to as the "staging concept." A specific map version is frozen and declared a stable branch. Updates are then continued on a so-called development branch. Only relevant and / or critical changes are then incorporated into the stable branch.The authorizing authority can be, for example, the development team or a mapping office.

[0024] According to a further advantageous embodiment of the method, the base map and the map difference packages are stored in a central database on a central processing unit. This enables central access to the base map and the map difference packages, so that the base map and the map difference packages can be made accessible to a large number of different stakeholders simultaneously. For example, new map difference packages can be imported into the central database and distributed accordingly to customers or users of the digital road map. The central processing unit can be a cloud server, for example. The cloud server can be operated by a map manufacturer or a vehicle manufacturer.

[0025] A further advantageous embodiment of the method according to the invention further provides that the base map is introduced into a computing unit of a vehicle; a selection of map difference packages is introduced into the computing unit of the vehicle; the digital road map is versioned in the computing unit of the vehicle by forming at least one continuous version chain using at least a subset of the selection of map difference packages; and a current map version of the digital road map is applied in the vehicle by a vehicle function.

[0026] The vehicle function could, for example, be an at least partially automated mode of operation of the vehicle, which reads relevant information from the current map version for controlling the vehicle. Another vehicle function could be the display of the current map version of the digital road map on a display device in the vehicle.

[0027] Preferably, a smaller number of map difference packets are fed into the vehicle's processing unit than are stored in the central database. This reduces the memory requirements in the vehicle and the bandwidth required to transmit the map difference packets. Map difference packets that are particularly relevant to the vehicle are transmitted to the processing unit. To determine relevant map difference packets, for example, a travel route planned with the vehicle can be analyzed. Valid map difference packets for map sections along which the travel route runs are then transmitted from the central database to the vehicle's processing unit. In general, however, it is also possible for only a single map difference packet to be transmitted to the vehicle's processing unit.

[0028] To generate the current map version, it may be sufficient to apply only a subset of the selection of map difference packages transmitted to the vehicle to the corresponding base map. Multiple version chains can also be created, allowing switching between different current map versions in the vehicle particularly quickly and easily.

[0029] According to a further advantageous embodiment of the method, a computing unit in the vehicle uses a current map version of the digital road map to determine a navigation route from the vehicle's current location to a destination. This enables particularly reliable navigation guidance, since a current map version is always used to calculate the navigation route. The vehicle can generally comprise one or more computing units. A first computing unit can be provided for storing the base map and the map difference packages and for generating the continuous version chain of the digital road map, and a further computing unit can be provided for carrying out the navigation. However, both functions can also be integrated into one and the same computing unit.

[0030] The processing unit can be permanently integrated into the vehicle or embodied by a mobile device that communicates with a processing unit permanently integrated into the vehicle. The mobile device can be, for example, a smartphone running an application that enables implementation of the method according to the invention. The smartphone can communicate with the central processing unit, for example, via mobile radio.

[0031] According to a further advantageous embodiment of the method according to the invention, this also enables the wireless introduction of the base map and / or the selection of map difference packages into the vehicle's computing unit. However, it is generally also conceivable for the base map and / or a selection of map difference packages to be introduced into the computing unit via a cable, for example, during a vehicle maintenance interval. "Cabled" in this context includes the reading of any physical storage medium by the computing unit, such as an SO card, a USB stick, an optical storage medium such as a DVD or Blu-ray, or the like.

[0032] Communication between the vehicle's processing unit and the central processing unit can also take place via a wireless communication interface, for example, a telematics unit permanently installed in the vehicle. In addition to mobile communications, any wireless communication technology can be used for communication, such as Bluetooth, NFC, WLAN, particularly using the Wi-Fi standard, and the like.

[0033] According to the invention, in a vehicle with a computing unit, the computing unit is configured to carry out a method described above. The vehicle can be any vehicle, such as a car, truck, van, bus, or the like. The vehicle can have at least one at least partially automated driving function, in particular a driving function that relies on the provision and processing of current map data.

[0034] Further advantageous embodiments of the method according to the invention for versioning digital road maps by means of incremental updates and of the vehicle emerge from the exemplary embodiments which are described in more detail below with reference to the figures.

[0035] Showing: Fig. 1 shows a schematic process flow for versioning digital road maps using incremental updates according to a known procedure; Fig. 2 shows a schematic detailed view of a map difference package; Fig. 3 shows a schematic representation of a data set of a digital road map to be stored when the digital road map is updated according to a method according to the invention; Fig. 4 shows a schematic process for generating a version chain of successive map versions; Fig. 5 shows a schematic view of an ecosystem used to implement the method according to the invention; and Fig. 6 shows a schematic representation of the generation of various version chains of the digital road map in a vehicle.

[0036] Figure 1shows the process for generating different versions of a digital road map using incremental updates, as is known from the prior art. Monolithic data sets, i.e., contiguous, relatively large files for creating a digital road map, are symbolized in the figures by boxes with a thick black border. Figure 1 As shown, a first map version KV1 of a digital road map is updated to a new version by importing a first map difference package Δ1. Only the map features of the first map version KV1 that need to be changed are modified. This increments the version identifier of the digital road map, creating a second map version KV2. The second map version KV2 is then also saved as a monolithic data block.

[0037] Similarly, by importing a second map difference package Δ2, the second map version KV2 is updated to a first, third map version KV3. Different variants of a third map version KV3 are to be created, for example, for different application purposes or different customers. Thus, a third map difference package Δ3 is applied to the second map version KV2 to create a second, third map version KV3.2 in addition to a first, second map version KV3.1. This process is also referred to as "forking."

[0038] By importing a fourth, fifth, and sixth map difference package (Δ 4 , Δ 5 , Δ 6 ), additional map versions (KV4, KV3.2.1, and KV3.2.2) are generated analogously. This involves a relatively high level of effort, as each map version is derived from a monolithic dataset, and updates must be imported to maintain it. Furthermore, a high storage requirement is required, as each map version (KV1, KV2, KV3.1, KV3.2, KV4, KV3.2.1, and KV3.2.2) must be saved as a monolithic dataset.

[0039] Figure 2 shows a more detailed view of a map difference packet Δ. A map difference packet Δ comprises at least one single change 1 of a map feature. However, a map difference packet Δ can also, as in Figure 2shown, include several individual changes 1 for different map features. In general, it is also possible for each map difference package Δ to contain only a single individual change 1.

[0040] A map feature is a combination of a map object, for example a road section, a junction, a traffic sign, a traffic light or the like, and map object properties valid for the respective map object, for example a valid speed limit, a direction of travel, a time period, a geoposition or the like.

[0041] With the help of a method according to the invention, it is possible to significantly reduce the effort required to create, manage, and use different versions of the digital road map. Figure 3a schematic representation of a data set of the digital road map to be saved. The representation is in tabular form, with the first column of the table showing a version identifier Version of the digital road map, the second column a complete data set 7, and the third column the respective version change 8 to be saved. As can be seen, in the first version V1 the complete digital road map is saved as a monolithic data set in the form of a base map BK. To update to a second version V2 a change is imported into the digital road map. In this case only the change shown in the second row and third column is saved in the form of a map difference package Δ. Analogously for a third version V3 only the change shown in the third row and third column is saved.Thus, complete monolithic data sets do not need to be stored for different versions of the map, but only the monolithic data set of the base map BK and the changes to be applied via the map difference packages Δ. This enables particularly efficient data management with regard to the amount of data to be transferred and stored.

[0042] According to the invention, to generate a current map version KVn, the individual map versions of the digital road map are arranged in a chain of versions 2, as shown in Figure 4 For this purpose, a version hash #n-1 of a previous card version KVn-1 and a card difference packet Δn to be applied are read into a hash function as input values ​​to generate a version hash #n for the current card version KVn. Figure 4The procedure shown begins with the base card BK and the generation of a first version hash #1. The base card BK represents a first card version KV1. The first version hash #1 is read into the hash function with a first card difference packet Δ1 to generate a second version hash #2. The first version hash #1 and the first card difference packet Δ1 form a second card version KV2.

[0043] Analogously, the second version hash #2 and a second card difference packet Δ2 are added to the hash function to create a third card version KV3.

[0044] The process for creating version chain 2 can thus be compared to creating a blockchain. Creating version hashes for the respective map versions ensures that changes to a digital road map cannot be tampered with and can be clearly traced.

[0045] Figure 5 shows an ecosystem used to implement the method according to the invention. This comprises a central processing unit 4, for example a cloud server, which includes a central database 3. The base map BK and the various map difference packages Δ are stored in the central database 3. In Figure 5A plurality of different map difference packages Δ is shown, with different map difference packages symbolized by a different number in the index. The central database 3 can be used to store different base maps BK. For example, a first base map BK1 and a second base map BK2 are stored in the central database 3. A respective base map BK1, BK2 can form a digital road map of a different geographical region, for example, of different countries.

[0046] The method according to the invention is used to update a digital road map stored in a vehicle 6. For this purpose, the vehicle 6 comprises a computing unit 5 in which at least one base map BK and at least a selection of the map difference packages Δ are stored. For communication with the central computing unit 4, the vehicle 6 has a wireless communication interface 9.

[0047] In vehicle 6, as Figure 6 shows one or more different version chains 2 according to the Figure 4 shown procedure. For this purpose, the selection of map difference packages Δ stored in the processing unit 5 is used. For the respective version chains 2, different combinations of map difference packages Δ can be used. Version chains 2 actively used in the vehicle are shown in Figure 6symbolized by a solid line and generateable version chains 2 by a dashed line.

[0048] As shown, it is possible for more than one version chain 2 to be used simultaneously in vehicle 6. For example, different vehicle functions can use different map versions. For example, a navigation system can access a fourth map version KV4, and a system for deriving automated control commands for vehicle 6 can access a sixth map version KV6. To generate the fourth map version KV4 and sixth map version KV6, the second and third map versions KV2 and KV3, as well as a fifth map version KV5, were generated in the respective version chains 2. Because only a single base map BK needs to be maintained as a monolithic data package, the storage space available in vehicle 6 can be used particularly efficiently. In addition, new updates can be installed particularly quickly and reliably.For different use cases, you can switch between different card versions particularly quickly and easily.

Claims

1. Method for versioning digital road maps by means of incremental updates, comprising the following method steps: - providing a base map (BK); - applying a hash function to the base map (BK) to generate a version hash (#1) of the base map (BK); - providing map difference packets (Δ), wherein a map difference packet (Δ) comprises at least one individual change (1) to a map feature; - versioning the digital road map by forming at least one continuous version chain (2), starting with the base map (BK), wherein for this purpose: - to generate a current map version (KVn), a map difference packet (Δn) to be applied is linked to the map version (KVn-1) located before the current map version (KVn) in the version chain (2), wherein for this purpose the version hash (#n-1) of the previous map version (KVn-1) and the map difference packet (Δn) to be applied are entered as input variables into the hash function in order to generate a version hash (#n) for the current map version (KVn).

2. Method according to claim 1, characterized in that a current map version (KVn) is only included in the version chain (2) if an authorizing instance releases the current map version (KVn).

3. Method according to claim 1 or claim 2, characterized in that the base map (BK) and the map difference packets (Δ) are stored in a central database (3) on a central computing unit (4).

4. Method according to any of claims 1 to 3, characterized in that - the base map (BK) is introduced into a computing unit (5) of a vehicle (6); - a selection of map difference packets (Δ) is introduced into the computing unit (5) of the vehicle (6); - the digital road map is versioned in the computing unit (5) of the vehicle (6) by forming at least one continuous version chain (2) using at least some of the selection of map difference packets (Δ); and - a current map version (KVn) of the digital road map is used in the vehicle (6) by a vehicle function.

5. Method according to claim 4, characterized in that a computing unit (5) in the vehicle (6) uses a current map version (KVn) of the digital road map to determine a navigation route from a current location of the vehicle (6) to a target location.

6. Method according to either of claims 4 to 5, characterized in that the base map (BK) and / or the selection of map difference packets (Δ) are wirelessly introduced into the computing unit (5) of the vehicle (6).

7. Vehicle (6) comprising a computing unit (5), wherein the computing unit (5) is designed to carry out a method according to any of claims 1 to 6.