Description
The core of any localization system is the sensor fusion unit in which its capabilities are limited by the performance of the sensors and underlying fusion algorithms. Of the different sensors, the Global Positioning System (GPS) sensor can provide information on the ground truth (GT) which can be leveraged along with other in-vehicle sensors to achieve accurate absolute localization. However, the GPS signal can be blocked by tall buildings, bridges, or tunnels in urban areas. Furthermore, the GPS is vulnerable to malicious attacks and signal spoofing. This motivates the value of a reliable absolute localization system that does not use GPS. Considering the operating areas of autonomous cars, one of the best ways to achieve such a GT is infrastructure.
Passive : In the paper, Localization in Global Positioning System–Denied Environments Using Infrastructure-Embedded Analog-Digital Information, we proposed Passive Infrastructure Localization in which the localization unit is in the car and GT is inferred from ”smart infrastructure”, using appropriate in-vehicle sensors. The ”smart infrastructure” is essentially a series of ”smart landmarks” that provides (i) digital identification information (such as can be obtained through a bar code or QR code), which can be read with very low uncertainty, and (ii) analog information about the landmark (such as the GT and geometric parameters of the landmark), which is obtained by cross-referencing the digital identification of the landmark to a database (which can be either stored on-board the vehicles, or made available on the cloud using relatively low-bandwidth services). Sensors are tailored to be able to read not only the digital information of the landmark, but also perform relative localization of the ego-vehicle with respect to the landmarks, leveraging the analog information extracted on the landmark.
Active: The term ”Active” implies that infrastructure itself is actively taking part in localization instead of just providing GT. In this method the localization task for all vehicles on the road is fully conducted by infrastructure itself and fused information is transferred to vehicle via wireless communication. The advantage of this method is that it can offload some of the computational weight from the ego-vehicle and provide a centralized localization unit. Here the GT information is already available in the infrastructure from the location of sensing equipment. Since the sensors are stationary, their exact location combined with their output estimation can provide us with the absolute localization.
Participants
Samin Moosavi, Andrew Weaver, Tyler Marr
