Though Apple remains tight-lipped on its self-driving car technology, a recently published patent gives a sneak peek into the Cupertino-based tech giant's plans — specifically a navigation system designed for autonomous vehicles.

The patent, simply titled "Autonomous Navigation System," was published by the U.S. Patent and Trademark Office (USPTO) on Thursday, Dec. 21. However, the patent application was originally filed back in 2015. This seemingly confirms that Apple has been working on self-driving car technology for a couple of years already — despite the tech giant only confirming such plans last June.

Based on the abstract, Apple has developed a system that will make autonomous navigation more efficient. Currently, autonomous vehicles' navigation is based static information like maps, along with sensors that identify real-time information on the car's surroundings — which tend to change daily.

Apple's system, on the other hand, will be able to navigate autonomous vehicles without having to rely on data received from external sources. The navigation system is able to create virtual characterizations of driving routes based on the ones that are used most often by drivers.

When the system meets a confidence threshold indication about a particular route, it will be able to navigate the vehicle autonomously. The navigation system is able to change routes depending on weather, construction, driving rules, etc. Thus, there is no need to constantly remake detailed maps.

The patent also detailed the particular user interface that will be used by Apple's navigation software. Because several virtual characterizations of routes can be generated, the system will provide drivers with the choice to select alternative routes depending on both the static and dynamic features of these roadways. Apple's navigation software will likewise allow drivers to switch from manual to autonomous mode.

Though there is no guarantee that the navigation system patented by Apple will be used in commercial vehicles — especially since the document is already a couple of years old, the recently published patent is still able to give some insight into Apple's plans for their self-driving car technology.