A brief discussion on the application of UWB in autonomous driving

With the CCC3.0 specification as the theoretical guidance, the interconnected third-generation digital key solution is realized through the complementary advantages of UWB, BLE, and NFC. The typical system solution is the interconnected PEPS solution released by Continental in August 2020 and mass-produced on the 2021 BMW 5 Series. As shown in the figure below, the whole solution arranges 7 UWB nodes and 3 BLE nodes, of which 4 UWB nodes are located at the headlights and taillights, and 3 UWB nodes are arranged in the middle of the roof from the front cabin to the tailgate. The positions of the 3 BLE nodes are close to the positions of the 3 UWB nodes on the roof.

When the owner brings the smart key close to the vehicle, the vehicle's BLE node can detect the smart key's BLE signal at a maximum distance of 80 meters. The vehicle's BLE node wakes up the body domain controller, and the body domain controller controls the welcome light to slowly light up, thus entering the welcome state. At the same time, the vehicle's UWB node is awakened. When the distance between the owner's smart key and the vehicle is less than 10m, the vehicle's UWB node can accurately sense the owner's location in real time through positioning means. At this time, the owner only needs to pull the door to automatically unlock it. In addition, the vehicle will also be equipped with NFC near-field communication function. In special circumstances such as when the smart key is out of power, NFC near-field communication can be used to unlock and start the vehicle.

(2) PEPS+AVP solution

The precise positioning advantage of UWB has attracted more and more attention in the field of autonomous parking. If the AVP function is realized by reusing the UWB node with PEPS function, it can be said to kill two birds with one stone. The project chief engineer can wake up laughing in the middle of the night. China Electronics Star provides such a UWB PEPS+AVP solution that can make the project chief engineer wake up laughing in the middle of the night. A feasible vehicle-side UWB node layout scheme is shown in the figure below. A total of four UWB PEPS nodes are placed at the headlights and taillights, and the fifth UWB PEPS+AVP node is placed on the roof. The fifth node can receive UWB signals both inside and outside the car, and is also a key node for realizing the AVP function.

When working in PEPS mode, the fifth UWB node works together with the other four UWB nodes to complete the measurement of the smart key position, and send the ranging information to the vehicle body domain controller to complete the calculation of the smart key position, thereby determining the subsequent unlocking and starting operations. When working in AVP mode, the fifth node begins to continuously receive UWB positioning messages broadcast by UWB nodes laid in the parking lot. The message contains information about parking spaces in the parking lot, similar to the longitude and latitude information in the GNSS positioning signal. The vehicle-side UWB node sends the received positioning message to the intelligent driving domain controller to calculate the coordinates of the vehicle in the garage, and further inputs it to the planning control module for the implementation of the AVP function. When designing the fifth node, the complex scenarios that the AVP function has to face were taken into consideration, so the RF performance will be better than the other four UWB nodes. At present, China Electronics Star can achieve signals emitted by garage UWB nodes of no less than 50 meters.

(3) PEPS + Kick Radar + Liveness Detection Solution

If the reuse of PEPS UWB nodes to realize the AVP function is considered to be a function that can be applied on a large scale in the short term, considering the support of the parking lot infrastructure. Then, the reuse of PEPS UWB nodes to realize the detection of kicking door movements and the detection of vital signs in the car is a more practical and urgent need. Qingyan Xunke provides such a solution. By matching the BLE node, the identity verification and authentication of the vehicle and the owner's smart key within a range of 20m can be realized, and the UWB node can be activated to start the precise positioning function. When the smart key is within 3~10m of the vehicle, the vehicle welcome function can be triggered and the lights can be automatically turned on. When the vehicle UWB node detects that the smart key is within 1~3m of the vehicle, the door can be automatically unlocked, accompanied by flashing turn signals and short horn beeps. When the user enters the car, the vehicle can be started with just one button. More importantly, this solution can detect the state of vital signs in the car in real time by reusing the UWB antenna in the car, including dynamic human movements and static human breathing, so as to realize reminders of people and pets staying and realize intelligent liveness detection. By reusing the UWB node on the left or right rear of the vehicle, accurate detection of the door-kicking action can be achieved, thereby realizing the automatic opening function of the trunk.

VI. Summary

We are in the midst of a major change in the automotive industry that has not been seen in a century, and the automobile industry is making great strides towards intelligence. However, all technologies are not achieved overnight. The development of things needs to be combined with the right time, right place, and right people. It is a gradual process. Just as BLE and UWB technologies have appeared many years ago, they have also been successfully applied to various sub-fields such as industry and military, but have not been applied to the PEPS system of automobiles. I don’t know which predecessor first thought of applying BLE and UWB technologies to the PEPS system of automobiles. As an engineer, it is a rare opportunity to have such an ability. This requires not only a deep foundation in basic technology, but also a mind with fantastic ideas. I am afraid that this is also an epiphany that can only be obtained through intensive cultivation and continuous improvement.