ASAM OpenCRG defines afile format for the description of road surfaces. It was originally developed to store high-precision elevation data from road surface scans. The primary use for this data is in tire, vibration or driving simulation. Precise elevation data allows realistic endurance simulation of vehicle components or the entire vehicle. For driving simulators, it allows a realistic 3D-rendering of the road surface. The file format can also be used for other types of road surface properties, e.g. for the friction coefficient or grey values.
Thestandard describes a method to store the data in a specific layout, called "curved regular grid" (abr. CRG). The advantages of this method are high memory efficiency, low computation time for file generation and data processing in simulation tools, and high accuracy of positioning the data onto road networks.
The basic principle for describing the road surface is to place the data into a grid along a road reference line. Line segments are described by a start position and heading angle. The grid is produced by longitudinal cuts (columns) and lateral cuts (rows) along consecutive line segments. Each cell in this grid has a value, typically the elevation. The road center line also includes the end position, which can be used to detect and correct a potential drift of the placement of the data on roads.
ASAM OpenCRG definesASCII and binary file formats with clear-text headers. The header contains road parameters for the reference line and the overall configuration of the longitudinal sections, a definition of the data format ( ASCII and binary), the sequence of data which is expected in the trailing data block, and modifier and option parameters. Furthermore, OpenCRG-files may contain references to other files (typically containing the actual data) to handle different parameters for the same data set.
Data from ASAM OpenCRG can be included in OpenDRIVE road network descriptions. The dynamic content of driving simulations, such as vehicle maneuvers, can be described with ASAM OpenSCENARIO. The three standards complement each other and cover the static and dynamic content of in-the-loop vehiclesimulation applications.
Thestandard is delivered with software libraries in ANSI-C and MATLAB. The libraries for both languages contain functions for reading CRG files, and for modifying and evaluating the imported data. In addition to that, the MATLAB library contains functions to generate, analyze and visualize the data.
Audi AG, BMW AG, Daimler AG, Porsche AG, VIRES Simulationstechnologie GmbH, Volkswagen AG.
Road map to further develop ASAM OpenCRG
The participants of the Proposal Workshop ASAM OpenDRIVE and ASAM OpenCRG (Jan 15 - 16, 2019) decided to propose one project to adapt the current version of OpenCRG to ASAM requirements (Transfer Project) while additionally implementing a few new features (Further Development Project). The aim is to finish the project quickly. More complex developments should be addressed in a separate project.
Currently the project proposal is written. After publication of the proposal, all members are invited to sign up for participation in the work group. (To be informed about new proposals subscribe to our newsletter)
ASAM OpenCRG Transfer and Further Development Project
After publication of the project proposal(s), members and non-members have the opportunity to review and comment the proposals and to enroll in the project group(s). Participation in a project group requires ASAM membership.
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