UPDATING A DIGITAL MAP

Description

[0001] The present invention relates to a method for updating a digital map stored in a vehicle, a method for carrying out a modification process of a digital map stored in a central database, a vehicle and a central computer.

[0002] Modern vehicles, especially motor vehicles, often have built-in navigation systems that can determine the current geographical position of the vehicle and calculate a route to a destination. For this calculation, navigation systems have digital maps stored in the vehicle. To ensure that such digital maps stored in the vehicle are always as up-to-date as possible, there is a need to update a digital map as frequently and as comprehensively as possible. It is known to update digital maps by inserting a data storage device (e.g. a CD, a USB drive, or similar) into the vehicle on which updated map data is stored. Such a data storage device can either remain in the vehicle, thus replacing the data storage device of the digital map previously located in the vehicle, or its contents can be copied onto the data storage device of the digital map located in the vehicle.

[0003] Modern vehicles often have devices for wireless data communication with external communication participants. For example, vehicles can be configured to exchange data with the Internet via mobile phone networks. Such data communication devices offer another option for updating a digital map stored in the vehicle, namely by obtaining the updated map data via the mobile phone connection. Since the data volume that can be transmitted via such a mobile phone connection is generally limited for technical and economic reasons, updating the entire digital map via a mobile phone connection is problematic.

[0004] To solve this problem, it is known to update only individual map objects, not the entire digital map. For example, a digital map can be divided into geographical regions. When updating the digital map, for example, only those map objects located in the same geographical region as the vehicle can be updated. Such a partial update of the digital map can lead to inconsistencies. This means that the digital map created by the update contains logical inconsistencies. For example, if a new road is added through an update without the roads to which the new road is connected being updated at the same time, the new road could appear "in limbo" in the digital map created by this update.In other words, this digital map would show the new road, but there would be no way to get to that road.

[0005] US 2012 / 0130944 A1, DE 10 2007 048 264 A1, and WO 2005 / 019773 A1 disclose different methods for updating a digital map divided into areas (also referred to as tiles, partitions, or "meshes"). What the proposed methods have in common is that, instead of updating the entire digital map, only individual areas are updated. WO 2005 / 019773 A1 recognizes the resulting problem of possible inconsistencies; as a solution, it is proposed to keep the areas as small as possible.

[0006] To solve the problem of inconsistencies, DE 103 37 621 A1 proposes first selecting a subset of elements of the digital map to be updated on the vehicle side and then requesting an update of this subset of elements. Upon receipt of such a request, the central computer automatically selects an additional subset of elements in addition to the subset of elements to be updated in such a way that the digital map is internally consistent after the update. In other words, a central computer supplements a requested set of map objects in such a way that the digital map created by the update is internally consistent. In practice, such methods, in which all map objects required for a consistent map change are determined using a digital map stored in a central database, have proven to be complex.This is due to the high degree of interdependence between map objects in a digital map. Therefore, conventional consistency check methods in practice lead to a "chain reaction," causing large portions of the digital map to be updated, which runs counter to the need to minimize the amount of data transferred.

[0007] Digital maps are usually made available by map providers in central databases. These central databases are accessible via central computers, such as internet servers. To update the digital map in the central database, new map objects are first recorded, for example, through recording drives with the map provider's recording vehicles. These new map objects are added to the database but are not yet made accessible. At a certain point in time, the data set is "frozen." This means that no further map objects can be added or updated. The entire digital map is then checked for consistency and corrected and / or supplemented as necessary. The resulting current version of the digital map is then released, i.e., made accessible. In other words, a digital map is not "continuously" updated.Rather, updated versions of the digital map are published at specific intervals.

[0008] Based on the state of the art, the task is to improve the updating of a digital map stored in a vehicle in such a way that the updated map is consistent and at the same time the amount of data transmitted is small.

[0009] The object is achieved by a method having the features of independent claim 1. Further aspects of the invention relate to a method having the features of independent claim 5, a vehicle according to claim 6 and a central computer according to claim 7. Advantageous developments of the invention are the subject matter of the dependent claims.

[0010] The inventive concept is already reflected in the data storage in the central database. Aspects of the invention therefore relate to a method for carrying out a modification process on a digital map stored in a central database, wherein the map comprises a plurality of map objects. A map object can be, for example, a street or a street section (also referred to as a "link") or a "point of interest" (POI). Each map object is assigned an object identifier and a version number.

[0011] To carry out the change process, the following steps are carried out according to the invention. First, at least one map object is changed. The respective version number of each changed map object is incremented, i.e., increased by a counter. This is not to be understood as being limited to the incrementation of natural numbers. A person skilled in the art is aware of a variety of different methods for storing version numbers that are suitable for the present application. Furthermore, according to the invention, a change process data record is stored, which the object identifier of the at least one changed map object, the version number valid before the change process and / or the incremented version number of the at least one changed map object and an identifier of the change process includes.

[0012] If a map object is newly added during a change process, it is assigned a version number that indicates that it is a newly added map object (e.g. "Version 1").

[0013] In other words, according to the invention, not only are changes made to the digital map, but these changes are also documented. This makes it possible to understand at a later point in time how the digital map was changed. In particular, it is possible to understand which map objects were changed in relation to one another during a change process. It should be noted that according to the invention, it is not necessary to store older versions than the current version of a map object itself. Therefore, there is no significant additional storage requirement for implementing the invention.

[0014] The above-described inventive method for carrying out a change process of a digital map stored in a central database is intended to be used as follows. A change process of the digital map should inherently result in a consistent change to the digital map. In other words, the digital map should remain consistent after the change process. For this to happen, it is necessary that, along with the change to a first map object, those other map objects affected by the change to the first map object (so-called "dependent map objects") are also changed. This will be explained in more detail below using an exemplary embodiment.

[0015] This eliminates the need, as described above, to freeze the digital map at specific intervals and check its overall consistency. Instead, the digital map can now be updated continuously, with each individual change being carried out in such a way that the map's consistency is maintained.

[0016] The idea underlying the invention is also reflected in a method for updating a digital map stored in a vehicle. The map comprises a plurality of map objects, each map object being assigned an object identifier and a version number. In other words, the structure of the digital map stored in the vehicle corresponds to that of the digital map stored in the central database. However, some or all of the map objects of the map stored in the vehicle may not be up to date (as determined by the digital map in the central database). This may also mean that a specific map object is not stored in the vehicle at all, namely if this map object has not been updated in the vehicle since it was added to the central database (in this case, added for the first time).

[0017] The procedure includes the following steps.

[0018] First, a first map object or several first map objects to be updated are determined. Subsequently, a request data record for updating the first map object or the first map objects is transmitted from the vehicle to a central computer. It should be expressly pointed out that this and all subsequent method steps can also be carried out for a plurality of first map objects, although this will not be explicitly mentioned below for reasons of better readability. The request data record comprises the object identifier and the version number of the first map object. The central computer can, for example, be an internet server of a map provider with which the vehicle can exchange data via a cellular connection.

[0019] In the next step, a change process of the first map object is determined compared to the version of the first map object identified by the sent version number. In other words, a check is made to determine whether the version of the first map object stored in the vehicle is up-to-date. If this is not the case, the first map object has been updated in the central database by at least one change process. The change processes that changed the first map object from its previous version (present in the vehicle) to its current version (present in the central database) are then determined. Each such change process has an identifier.

[0020] In the next step, for each previously identified change process, the other map objects changed during this change process are determined. An update data set is then compiled, which a current version of the first map object, the version number of the current version of the first map object and the respective object identifier and the respective version number of the other map objects This update data set is transmitted from the central computer to the vehicle.

[0021] In other words, the invention provides that the vehicle first requests a current version of a specific map object (namely the first map object). A current version (including information about the corresponding version number) is only transmitted to the vehicle from this first map object. In addition, however, the vehicle receives, as part of the update data set, information about which other map objects were changed together with the first map object. As explained above, the method for carrying out a change process of the digital map is advantageously used in such a way that, during a change process, several map objects are changed together in such a way that the consistency of the digital map is maintained.Conversely, the information contained in the update data set transmitted to the vehicle according to the invention enables the vehicle to check the consistency of its digital map and, if necessary, to establish it through further steps.

[0022] For this purpose, the version numbers of the additional map objects contained in the update data set can advantageously be compared with the version numbers of the additional map objects contained in the digital map stored in the vehicle. The additional map objects to be updated can then be determined. For this purpose, it is preferably possible to check whether and, if so, in which version the additional map objects are contained in the digital map stored in the vehicle. If an additional map object is not contained in the digital map stored in the vehicle, or if the version number of an additional map object contained in the digital map stored in the vehicle is lower than the version number of the additional map object transmitted as part of the update data set, this additional map object can be identified as the additional map object to be updated.For each such additional map object to be updated, the method according to the invention can now be carried out from the beginning.

[0023] It is particularly advantageous to perform the process iteratively until no further map objects need to be updated have been identified. The result is a consistent digital map in the vehicle, since the dependent map objects for each updated map object have been checked and, if necessary, also updated.

[0024] In a further embodiment, the step of determining the first and / or further map objects to be updated can comprise determining the map objects located within a predetermined radius around a location of the vehicle. When route guidance is activated, i.e. when a destination is set and a route to the destination is calculated, the step of determining the first and / or further map objects to be updated can alternatively or additionally comprise determining the map objects located along the route from the location of the vehicle to the destination. In order to also cover the possible case that the driver of the vehicle deviates slightly from the route (e.g.to find a nearby restaurant for a break or to see a tourist attraction), the step of determining the first and / or further map objects to be updated may additionally or alternatively comprise determining the map objects located within a corridor of predetermined width around the route.

[0025] In a further embodiment, it may be provided that, following the update of the map objects located along and / or near the route, the route calculation is repeated. It is conceivable that a different route results from the map update. In this case, it may be provided to perform the method again with the modified route. This can also be repeated iteratively until the route no longer changes and / or no map objects to be updated are determined.

[0026] The invention further comprises a control unit intended for installation in a vehicle, which is configured to carry out the method steps of the method described above to be carried out on the vehicle. Such a control unit can, in particular, be or comprise a so-called head unit. The invention further comprises a vehicle with such a control unit.

[0027] The invention further comprises a central computer which is configured to carry out the method steps of the method described above to be carried out on the central computer side.

[0028] Finally, the invention comprises a computer program product comprising instructions which, when executed on the control unit and / or the central computer, effect the execution of the method steps described above.

[0029] Further embodiments of the invention are explained below using exemplary illustrations. Fig. 1 shows a sequence of data communication according to an embodiment of the method according to the invention and Fig. 2 shows a partial representation of map objects in a central database.

[0030] In the figures, identical reference numerals identify identical or equivalent features of the illustrated embodiments of the invention. It is pointed out that the illustrated figures and the associated description are merely exemplary embodiments of the invention. In particular, representations of combinations of features in the figures and / or the description of the figures are not to be interpreted to mean that the invention necessarily requires the implementation of all of the features mentioned. Other embodiments of the invention may contain fewer, more and / or different features. The scope of protection and the disclosure of the invention arise from the appended claims and the complete description. It is also pointed out that the representations are schematic representations of embodiments of the invention.The arrangement of the individual elements shown relative to one another is chosen only as an example and can be chosen differently in other embodiments of the invention.

[0031] In Fig. 1 a data communication sequence between a vehicle 1, a central computer 2 and a central database 3 is shown. It should be noted that the central computer 2 and the central database 3 can also form a common unit. In particular, the central database 3 can be a component of the central computer 2. The central computer 2 can in particular be a server of a map provider that is accessible via the Internet. The connection between the vehicle 1 and the central computer 2 (which can therefore correspond to a connection between the vehicle 1 and the Internet) can be established, for example, by means of wireless data communication. In particular, the vehicle 1 can have a telematics module for this purpose that is set up for wireless data communication via WLAN and / or mobile radio networks (e.g. LTE, UMTS, etc.).

[0032] In a first method step 10, the vehicle 1 determines a first map object to be updated. In the present example, object 123 was determined as the first map object to be updated. Object 123 is, as shown in Fig. 2 (a) to indicate a road section ("link"). The dotted representation of the ends of the road in Fig. 2 (a) is intended to indicate that it continues in both directions. The reason why object 123 was determined as the first map object to be updated during the execution of method step 10 may, for example, be that a navigation system of vehicle 1 has calculated a route from the current location of vehicle 1 to a destination, which route includes the road section represented by map object 123.

[0033] With reference to the sub-figures (a), (b) and (c) of the Fig. 2 A practical embodiment of the method according to the invention for carrying out a change process of the digital map stored in the central database 3 will now be explained. Fig. 2 (a) an earlier one, the Fig. 2 (b) represents a later version of the digital map. A comparison of the two sub-figures (a) and (b) shows that the road comprising the road section 123 has been extended by a bypass 124. On the bypass 124 there is an object 125, which may be a "point of interest" (POI), for example a petrol station 125. The construction of the bypass 124 and the petrol station 125 may require further changes to the digital map, which are shown only for the sake of simplified representation in Fig. 2 are not shown. For example, the entrances and exits of road section 123 to and from bypass road 124 can be depicted by separate map objects.

[0034] To ensure the consistency of the digital map, a change process must include a change to all digital map objects 123, 124, 125 that have mutual dependencies. For example, it would not be possible to simply add the gas station 125 to the digital map during a change process. There would then be no way to reach the gas station 125 in the digital map changed in this way. Likewise, it would not lead to a consistent digital map if the bypass 124 were recorded, but not its connection to the road section 123 (e.g., exits, entrances, intersections, or similar; in Fig. 2 Methods, procedures, and tools for making changes to a digital map such that the result is consistent are known to those skilled in the art. These methods are not part of the present invention. However, for the present invention, it is important that each change process results in a consistent digital map.

[0035] The Fig. 2 (a) The previous version of map object 123 shown has the version number 1. The version shown in Fig. 2 (b) The later version of the digital map shown has the newly added objects 124, 125 and a later version of object 123. Therefore, objects 124, 125 each have the version number 1, whereas the version number of object 123 has been incremented and is now 2. In the central database 3, in addition to the actual map objects 123, 124, 125, a change process record 200 is stored. This is in Fig. 2 (c) The change process record 200 includes an identifier of the change process ("Change 200"), the object identifiers of the changed map objects 123, 124, 125 ("Object 123", "Object 124", "Object 125"), and the incremented version numbers of the changed map objects 123, 124, 125; the changed map object 123 receives the incremented version number 2 ("Version 2"), whereas the newly added map objects 124, 125 receive the version number 1 ("Version 1").

[0036] After completion of the method according to the invention for carrying out the change process of the digital card, the digital card therefore only contains the Fig. 2 (b) displayed versions of the map objects 123, 124, 125. However, by means of the change process data record 200, which is also stored in the map database 3, it can be traced which map objects have been changed due to their dependencies on one another.

[0037] It will now be discussed with reference to Fig. 1 The exemplary embodiment of the method for updating the digital map stored in the vehicle 1 is further explained. In step 20, the vehicle transmits a request data record 21 for updating the first map object 123 to the central computer 2. The update data record 21 contains the object identifier ("Object 123") and the version number ("v. 1") of the first map object 123.

[0038] In step 30, the central computer 2 forwards the information received from the vehicle 1 to the central database 3 and thus determines a change process 200 of the first map object 123 compared to the version of the first map object 123 designated by the sent version number. In other words, in this step 30, the central computer 2 queries the central database 3 as to whether and, if so, which changes have taken place to the map object 123 since version number 1.

[0039] In the present example, an updated version of map object 123, namely version number 2, is available in central database 3. The change of map object 123 from version number 1 to version number 2 was made during change process 200. Using the associated change process record 200, central database 3 can determine in step 40 whether and, if so, which additional map objects were changed during change process 200. In this case, these are map objects 124, 125, which were newly added during change process 200 and therefore each have version number 1.

[0040] In the following step 50, the central computer 2 compiles an update data set 51 containing the data and information described above, namely: the current version of the first map object 123 and its version number ("v. 2") and the respective object identifier and the respective version number of the other map objects 124, 125.

[0041] It should be noted that the additional map objects 124, 125 themselves are not part of the update data set 51. The update data set 51 merely contains the information necessary to uniquely identify these map objects 124, 125. In this way, vehicle 1 can later check whether it already has the current versions of the additional map objects 124, 125 or whether it still needs to request them from the central computer 2.

[0042] It should be noted that steps 30, 40, 50 performed by central computer 2 and central database 3 do not necessarily have to be executed in the form and order shown and described herein. Any database query known to those skilled in the art that results in the contents of update data record 51 can be used for the method.

[0043] In step 70, the update record 51 is transmitted from the central computer 2 to the vehicle 1. In some embodiments of the invention, it may be provided that this only occurs upon an explicit request 60 by the vehicle 1. In other embodiments, such a request 60 is not provided, and the central computer 2 carries out the transmission 70 of the update data record 51 directly after the compilation 50 of the update data record 51. An explicit request 60 can be advantageous if the vehicle 1 wishes to have the update data record 51 transmitted at a specific time at which, for example, a better data connection (e.g., a WLAN connection or a mobile radio connection with a higher data rate) exists.

[0044] Next, the version numbers of the further map objects 124, 125 contained in the update data set 51 are compared in the vehicle 1 with the version numbers of the same map objects 124, 125 in the digital map of the vehicle 1 (method step of comparing in Fig. 1 not shown). In the present example, it is determined that the additional map objects 124, 125 are not yet present in the digital map of the vehicle 1. Therefore, the additional map objects 124, 125 are determined as additional map objects 124, 125 to be updated. Based on this step of determining the map objects to be updated, the previous method is subsequently carried out again. This essential similarity of the possibly iteratively executed method steps is in Fig. 1 by using the same reference numerals for the respective process steps (10-70).

[0045] Thus, in method step 10, map objects 124, 125 are identified as map objects to be updated. Subsequently, a request data set 21 for updating map objects 124, 125 is transmitted from vehicle 1 to central computer 2 (step 20). Method steps 30, 40, and 50 lead, as already described, to the compilation of an update data set 51. This now contains the current versions of map objects 124, 125 as well as the associated version numbers (each "v. 1"). Map objects 124, 125 were inserted into the digital map during the change process 200. As shown in Fig. 2 (c) As shown, the map object 123 was also changed during this change process 200, namely updated to version number 2. This information is therefore also part of the update data record 51, which is transmitted from the central computer 2 to the vehicle 1 in step 70.

[0046] For clarification, it should be noted that in the second run of the method just described, the map objects 124, 125 represent the first map objects to be updated, whereas the map object 123 represents a further map object.

[0047] Subsequently, in vehicle 1, the version number of the additional map object contained in the update data record 51 (thus map object 123 with version number 2) is again compared with the version number of the additional map object contained in the digital map stored in vehicle 1. In this case, the comparison shows that map object 123 in vehicle 1 is already in version 2 and therefore no longer needs to be updated. Since no additional map objects to be updated have been identified, the method is terminated. Preferably, it is provided that only at this point in time, i.e. when all map objects 123, 124, 125 to be updated are present in vehicle 1, are the changes adopted in their entirety into the digital map of vehicle 1. This means that inconsistencies can also not arise during the execution of the method for updating the map.

Claims

1. Method for updating a digital map stored in a vehicle (1), wherein the map comprises a multiplicity of map objects (123, 124, 125), a map object (123, 124, 125) being a road section or a point of interest, wherein an object identifier and a version number are assigned to each map object (123, 124, 125), having the steps of - determining (10), in the vehicle, a first map object (123) to be updated, - transmitting (20) a request data record (21) for updating the first map object (123) from the vehicle (1) to a central computer (2), wherein the request data record (21) comprises the object identifier and the version number of the first map object (123), - determining (30), in the central computer, an operation for changing the first map object (123) in comparison with that version of the first map object (123) which is identified by the transmitted version number, - determining (40), in the central computer, further map objects (124, 125) changed during the change operation on the basis of a change operation data record (200), - compiling (50), in the central computer, an update data record (51) comprising ∘ a current version of the first map object (123), ∘ the version number of the current version of the first map object (123), and ∘ the respective object identifier and the respective version number of the further map objects (124, 125), - transmitting (70) the update data record (51) from the central computer (2) to the vehicle (1).

2. Method according to Claim 1, having the further steps of - comparing those version numbers of the further map objects (124, 125) which are contained in the update data record (51) with the version numbers of the further map objects (124, 125) contained in the digital map stored in the vehicle (1), - determining (10) the further map objects (124, 125) to be updated, and - carrying out (20-70) the method according to Claim 1 for the further map objects (124, 125) to be updated.

3. Method according to Claim 2, wherein the method is carried out iteratively until no further map objects to be updated have been determined.

4. Method according to one of the preceding claims, wherein the step of determining (10) the first and / or further map objects (123, 124, 125) to be updated comprises determining the map objects - in a predetermined radius around a location of the vehicle (1), and / or - along a route from a location of the vehicle (1) to a destination, and / or - within a corridor of a predetermined width around a route from a location of the vehicle (1) to a destination.

5. Method for carrying out an operation for changing a digital map stored in a central database (3), wherein the map comprises a multiplicity of map objects (123, 124, 125), a map object (123, 124, 125) being a road section or a point of interest, wherein an object identifier and a version number are assigned to each map object (123, 124, 125), having the steps of - changing one or more mutually dependent map objects (123, 124, 125), - incrementing the version number of the one or more changed map objects (123, 124, 125), - storing a change operation data record (200) comprising ∘ the object identifier of the one or more changed map objects (123, 124, 125), ∘ the version number of the one or more changed map objects (123, 124, 125) which was valid before the change operation and / or has been incremented, and ∘ an identifier of the change operation.

6. Vehicle (1) having a control device which is set up to carry out those method steps (10, 20) of the method according to one of Claims 1 to 4 which are to be carried out in the vehicle.

7. Central computer (2) which is set up to carry out those method steps (30, 40, 50, 70) of the method according to one of Claims 1 to 4 which are to be carried out in the central computer.