Patent Publication Number: US-2021164788-A1

Title: Certification of map elements for automated driving functions

Description:
CROSS REFERENCE 
     The present application claims the benefit under 35 U.S.C. § 119 of German Patent Application No. DE 102019218631.9 filed on Nov. 29, 2019, which is expressly incorporated herein by reference in its entirety. 
     FIELD 
     The present invention relates to a method for the certification of map elements for safety-critical driving functions, to a control unit, to a computer program and to a machine-readable memory medium. 
     BACKGROUND INFORMATION 
     Automated driving functions and vehicles having automated driving functions are becoming increasingly important. Up-to-date and precise maps are essential for a successful implementation of automated driving functions. 
     With the use of digital maps for automated driving functions, it is possible to compensate for limited sensor ranges and coverages of scanning areas of the sensors of vehicles and to enable a complete sensing of the surroundings. 
     In addition, digital maps may be created outside a vehicle environment using a normally higher computing power, as a result of which it is possible to process and provide more complex processing algorithms and a higher volume of data. The utilization of the maps by an on-board control unit requires less computing power than the vehicle-external creation of the maps. 
     In the case of safety-critical functions, however, the use of vehicle-externally created maps is problematic. If digital maps are utilized by an automated driving function of a vehicle, errors and inaccuracies during the creation of the map may result in hazardous traffic situations. 
     SUMMARY 
     An object of the present invention is to provide of a method for enabling a use of maps for safety-critical driving functions. 
     This object may be achieved with the aid of example embodiments of the present invention. Advantageous example embodiments of the present invention are described herein. 
     According to one aspect of the present invention, a method is provided for the certification by a control unit of map elements for safety-critical driving functions. The certification may preferably be carried out by a vehicle-external control unit or by a server unit. 
     The certification may be carried out for each digital map element of a digital map such as, for example, map tile or a map chunk, or for an entire digital map. 
     In one step, at least one observation variable of at least one mapping step of at least one map element is ascertained via a monitoring function after an implementation of the mapping step and is compared with a setpoint value of the observation variable. The mapping steps may be carried out preferably by the control unit. 
     The mapping may take place using mapping methods based, for example, on a graph modelling. For example, Graph SLAM methods may be used, which explicitly model vehicle positions and vehicle orientations, so-called vehicle poses. The following exemplary mapping steps may be carried out:
         measured data ascertained by sensors of multiple mapping vehicles are received by the control unit.   the received measured data are pre-processed.   the measured data received by different mapping vehicles are oriented geometrically. The orientation may take place with the aid of static landmarks and features, which are detectable by the control unit in different measured data sets.   after the orientation, the position of the static landmarks and also the poses of the mapping vehicles may be ascertained.   in one further mapping step, localization maps may be created from the landmarks. The trajectory driven by the mapping vehicles may be derived from the sequence of the vehicle poses.   foreign trajectories of other road users are contained in the measured data sets. Maps, which combine the historical behavior of the other road users, may be derived on the basis of the vehicle trajectories and foreign trajectories.   in addition to the analysis of the trajectories, the landmarks may be further processed to form planning maps.       

     The monitoring function in this case may be carried out according to one, according to multiple or according to each of the mapping steps cited by way of example, in order to validate the respective mapping steps and thus to ensure a correct and precise map creation. 
     In one further step, at least one result value is calculated via the monitoring function based on a comparison of the observation variable with the setpoint value of the observation variable for the at least one mapping step. 
     The result value may, for example, represent an accuracy or a quality of the respective mapping step and thus assess the at least one completed mapping step. 
     The result value may preferably be used to maintain a particular accuracy or a particular quality during the mapping step. A certification may not be issued if a predefined result value is not reached and the map element may not be used for safety-critical applications. 
     The at least one result value is subsequently stored as a certificate if the at least one result value or all calculated result values adhere to a tolerance range. The created certificate is subsequently linked to at least one map element. 
     The at least one map element including the associated certificate are provided to road users so that the road users are able to execute automated driving functions. 
     In the case of multiple mapping steps checked via the monitoring function, the respective result values for each mapping step may be combined, for example, in a total value in order to technically simplify the further handling and creation of the certificate. 
     When creating the total value, the respective result values may be weighted equally or to varying degrees. 
     The at least one map element may be provided with the linked certificate via a communication link to vehicles for carrying out automated driving functions. 
     Before the map element is used, the total value secured in the certificate for this map element may be decoded in the vehicle or by an on-board processing unit. The map element may then be used by the automated driving function or by a localization unit of the vehicle if the total value is positive or is within the tolerance range. 
     According to one further aspect of the present invention, a control unit is provided, that control unit being configured to carry out the method. The control unit may, for example, be an on-board control unit, a vehicle-external control unit or a vehicle-external server unit such as, for example, a cloud system. 
     According to one aspect of the present invention, a computer program is also provided, which encompasses commands which, when the computer program is executed by a computer or a control unit, prompts the computer to carry out the method according to the present invention. According to one further aspect of the present invention, a machine-readable memory medium is provided, on which the computer program according to the present invention is stored. 
     According to the BASt standard, the vehicle may be operable in an assisted, semi-automated, highly automated and/or fully automated or driverless manner. 
     The vehicle may, for example, be a passenger car, a truck or a robotaxi and the like. The vehicle is not limited to an operation on roads. Instead, the vehicle may also be designed as a watercraft, an aircraft such as, for example, a transport drone and the like. 
     With the method, it is possible to check the different map levels such as, for example, localization map, planning map and the like during the mapping, as a result of which the use of the map element in safety-critical functions of the vehicle is ensured. Map elements checked via the monitoring function may, in particular, fully meet the requirements of the ISO 26262 Standard. 
     According to one exemplary embodiment of the present invention, the at least one mapping step is carried out as a pre-processing of measured data of at least one sensor, as an orientation of pre-processed measured data, as a creation of a localization map, as a creation of a behavior map of road users and/or as a creation of a planning map. 
     The plurality of monitoring functions used may ensure that all relevant components or sections of the map creation are monitored. This measure increases the reliability of the entire system. 
     In the mapping step designed as a pre-processing of the measured data, the monitoring function may, for example, use the observation variables in the form of a number of measured data sets, an age of the measured data, and weather during the recording of the measured data, and compare them with setpoint values. The monitoring function may use as setpoint values, for example, a number of measured data sets of at least five, an age of the measured data of at most three hours, and weather that does not adversely affect the sensor system. 
     If a monitoring function is used for validating the orientation step of the measured data, so-called Olson&#39;s loops may be used as a measure of quality or as an observation variable. A setpoint value may, for example, be no greater than 0.05. 
     After the creation of the localization map as a further mapping step, a monitoring function may take a number of localization features as observation variables into account. The number of localization features may include, for example, at least 50 landmarks. 
     The mapping step carried out for creating the behavior map may also be checked via a monitoring function. For example, a number of used behavior patterns of different road users from at least 100 measured data sets may be present in order to enable a positive assessment of the mapping step via the monitoring function. 
     A subsequent creation of the planning map may be checked via a monitoring function in order, for example, to rule out inconsistencies between the map and legal requirements. For example, a number of detected inconsistencies such as, for example, a speed limit of 100 km/h within built-up-areas, which should be 50 km/h, may be used as an observation variable by the monitoring function. The setpoint value for the number of inconsistencies should not differ from zero. 
     The at least one monitoring function may, for example, be designed as a software module, which is executable by the control unit. 
     According to one further specific embodiment, one monitoring function each is carried out after each mapping step for ascertaining and validating observation variables of the respective mapping step. This measure may ensure that all relevant components of the map creation are monitored, which increases the reliability of the entire system. 
     According to one further exemplary embodiment of the present invention, the at least one result value ascertained via the monitoring function after each mapping step is conveyed via a communication link to a secured processing unit, for example, a secured SPS hardware unit, the at least one result value being stored as a certificate by the secured processing unit. 
     The results of the monitoring function or of the monitoring functions carried out after each mapping step may preferably be transmitted via a secured communication to a secured processing unit. 
     The processing unit is able to link the result values of the monitoring functions carried out for each mapping step logically to one value per map element. In this case, a weighting of the result values may be carried out, which have been ascertained from different mapping steps via the monitoring functions. For example, the result value for a pre-processing of measured data may be weighted lower than a result value of an orientation of the measured data. 
     The processing unit may, for example, be structured as a cluster of multiple error-protected SPS hardware elements and may thus provide a safety concept resembling a so-called AVP safety concept. 
     According to one further specific embodiment of the present invention, the result values ascertained via the monitoring function are conveyed via an encrypted communication link to the secured processing unit. With this measure, it is possible to carry out an additional safe-guarding of the result values before the processing unit combines the result values to form a total value. 
     According to one further exemplary embodiment of the present invention, a certificate is created for each map element, the certificate including a total value that combines all result values ascertained by the monitoring functions. In this way, a digital map made up of multiple map elements may be subdivided into subsections and thus certified in sections for safety-critical functions. As a result, the digital map may be used at least in sections for automated driving functions of vehicles. 
     The total value of the monitoring functions in the form of a certificate may preferably be added to each map element and may be conveyed via a secured communication link to the vehicle or to an on-board processing unit. 
     According to one further specific embodiment of the present invention, one certificate is created for each map element, the certificate including all result values ascertained by the monitoring functions. In this form, not only is a consolidated total value stored in the map element, but each result value of the monitoring functions is stored separately in the form of a certificate. 
     In this way, a decision about the weighting of the result values of the monitoring functions may be made by an on-board processing unit utilizing the map element. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred exemplary embodiments of the present invention are explained in greater detail below with reference to highly simplified, schematic representations. 
         FIG. 1  schematically shows a representation of a vehicle arrangement for illustrating one method in accordance with an example embodiment of the present invention. 
         FIG. 2  schematically shows a flow chart for illustrating the method according to one specific embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS 
       FIG. 1  schematically shows a representation of a vehicle arrangement  1  for illustrating a method  2 . Vehicle arrangement  1  includes one or multiple mapping vehicle(s)  4 . 
     Mapping vehicles  4  may, for example, be passenger cars equipped with a sensor system for detecting the surroundings. 
     Mapping vehicles  4  include sensors  6  for collecting measured data of surroundings U. 
     Sensor  6  may be designed as a LIDAR sensor, a radar sensor, a camera sensor and the like. 
     The measured data may be collected by on-board processing units  8  and may be transmitted via a communication link  10  to a vehicle-external control unit  12 . 
     Communication link  10  may, for example, be based on a WLAN, UMTS, GSM, 4G, 5G, and the like, transmission standard. 
     Control unit  12  is designed as a vehicle-external server unit and is able to receive the measured data of mapping vehicles  4  and use them for creating digital maps. 
     Control unit  12  is able to create and certify the digital maps, preferably via multiple mapping steps, so that the digital maps are provided to vehicles  14  or road users via a further communication link  11  for implementing automated driving functions. 
     A flow chart for illustrating method  2  according to one specific embodiment of the present invention is schematically represented in  FIG. 2 . Method  2  is used for the certification by control unit  12  of map elements for safety-critical driving functions. The mapping takes place in sections or map element by map element. For the sake of simplicity, method  2  is described with reference to one map element. 
     A first mapping step is carried out in a step  16 . The first mapping step may include, for example, a pre-processing or orientation of received measured data. 
     At least one observation variable of first mapping step  16  is subsequently ascertained after an execution of the first mapping step via a first monitoring function  17  and compared with a setpoint value of the observation variable. 
     One monitoring function  17 ,  19 ,  21  each is carried out after each mapping step  16 ,  18 ,  20  for ascertaining and validating observation variables of respective mapping step  16 ,  18 ,  20 . 
     A creation of a localization map, for example, may take place as a second exemplary mapping step  18 . An exemplary third mapping step  20  may include a creation of a behavior map of road users and or a creation of a planning map. Further intermediate steps or further mapping steps may be carried out which, for the sake of clarity, are not depicted. 
     One monitoring function  17 ,  19 ,  21  each is carried out after each mapping step  16 ,  18 ,  20 . Monitoring functions  17 ,  19 ,  21  may preferably be adapted to mapping steps  16 ,  18 ,  20 . 
     At least one result value is calculated via the monitoring function based on a comparison of the observation variables with setpoint values of the observation variables. 
     Result values ascertained by the monitoring function are conveyed to a secured processing unit  22 . Secured processing unit  22  may, for example, be designed as a secured SPS hardware unit. 
     The received result values are combined  24  by secured processing unit  22  to form a total value. In this case, the respective result values may be weighted to varying degrees. 
     In a further step  26 , the total value is stored in the form of a certificate and linked with the map element. 
     The map element thus certified may be subsequently provided  28  to road users  14 .