This part of the ISO 12188 specifies the process for evaluating and reporting the performance of agricultural vehicles equipped with auto-guidance systems based on a global navigation satellite system (GNSS) when operating in an automatic steering mode.
The main performance criterion is a relative cross-track error (XTE) distribution determined for a representative point on the vehicle when operating in a defined test setting.
The XTE integrates the uncertainties associated with the performance of the steering control as well as errors originating from the positioning device being used.
This standard focuses on auto-guidance system performance while travelling straight over a level surface only. Travel over slopped and/or curved terrain is not covered by this part of the Standard,