A French vineyard in the Loire valley is a beautiful sight, but the farm has trouble recruiting workers to weed their organically grown grapes. The young generation has moved to the cities leaving urban communities short on workforce. Solution: a fully autonomous tractor, developed by a French-based company Sitia, working tirelessly to weed the narrow rows between the grape vines. After a full month of weeding and hundreds of kilometers covered, Sitia approached the farmer to review the work done, and reimburse 2 grape vines, which were damaged during the month of operation. They were surprised to hear the farmer exclaim, “When I use my manual tractor to get the same job done, I damage at least two vines a day! How did your robot manage to be so careful?”. A high level of accuracy and integrity ensures high quality of autonomous operation.
But what exactly is integrity of positioning and how does it affect the performance and reliability of robots and other autonomous machines? Integrity is the truthfulness of positioning and positioning accuracy information, even if it means showing that the current position information is not as accurate as desired in a certain challenging environment. A part of delivering high integrity positioning is a statistical analysis called RAIM or RAIM+, where the latter takes this analysis to the next level as part of a larger positioning protection package.
Why is integrity critical for automation?
Let us take a closer look at GNSS receiver integrity in the sense of truthful reporting of possible positioning inaccuracies, and how overly optimistic reporting can result in hazardous autonomous operation. Reporting of receiver accuracy is done through positioning uncertainty, which is the maximum possible error on the calculated position. It gives a sense of risk of a positioning error especially necessary in challenging GNSS environments where the receiver “sees” only a limited number of GNSS satellites or where GNSS signals are degraded.