Ultra-Wideband Localization
Accurate distance and position sensing based on UWB
UWB Ranging Enables Localization
Ultra-Wideband localization is based on precise distance measurements between UWB devices such as anchors, tags, smartphones, infrastructure nodes, or vehicles. UWB technology measures the signal propagation time between two UWB sensors, typically an initiator and a responder, and uses the speed of light to determine the distance between them. If a setup contains multiple UWB devices, also referred to as UWB nodes or UWB anchors, the distances from one initiator to several responders can be measured and used as the basis for localization.
By combining several individual distance measurements, algorithmic localization methods such as tri- or multilateration can determine the position of a UWB sensor within a defined coordinate system. Additional signal enhancement methods, including noise suppression, weighted averaging, filtering, or machine learning, can further improve localization accuracy and robustness. This makes UWB suitable for applications where reliable proximity, position, or movement information is required, for example in secure access, EV charging, parking, test-track localization, industrial tracking, robotics, smart infrastructure, mobile devices, and other embedded localization systems.
The examples shown below focus on automotive scenarios and illustrate two different mounting topologies for UWB anchors inside a vehicle. The anchor positions define the base coordinate system in which additional UWB nodes, such as smartphones, key fobs, tags, or infrastructure elements, can be localized. The optimal mounting position depends on the target use case, the required localization accuracy, the covered interaction zones, and the integration constraints of the system.
Demo: UWB Localization
Embedded AI has been continuously developing UWB solutions for automobiles since 2017. The following video showcases some inspirations for locating the car key. The video also highlights the important inside-outside detection. The arrangement of the UWB anchors is chosen to achieve both optimal performance for outdoor uses and indoor monitoring (for more details, refer to the subpage on In-Cabin Sensing). This offers significant potential for saving costs, as a UWB sensor system can eliminate several conventional sensors.
Use Case: Secure Car Access and Keyless Entry
Security: Prevention of Relay Attacks
For keyless vehicle access (Keyless Entry), determining the key’s position is crucial to ascertain whether the person opening the door has the required access authorization (key on their person). Most conventional methods are vulnerable to relay attacks, where thieves copy and extended the radio signal of the key to spoof its the position.
By using UWB technology for key localization, relay attacks can be prevented. This is achieved through secure signal propagation time measurements, enabling secure distance measurements between the key and the vehicle. Thieves have no chance of gaining unauthorized access to the vehicle through signal spoofing.
Additional Effects of UWB
Precise key localization also allows for additional comfort functions, for example:
Tracking the Welcome Light based on position or illuminating the path to the vehicle in darkness.
Further unlocking methods can be enabled when combining this UWB approach with additional sensors and algorithmic methods:
- Gesture recognition (combined with UWB Radar)
- Authentication based on walking pattern (combined with IMU)
- Magic Key Gesture (combined with IMU)
- Foot-tap Gesture (combined with IMU)
- Rotation toward the vehicle (combined with IMU)
Use Case: Automated EV Charging Alignment
The following approaches exist for the automated charging of electric vehicles:
- Charging robot inserts a robot arm into the conventional charging socket of an electric vehicle (schematic illustration on the left).
- Charging robot/charging station docks automatically to the vehicle floor from below, either as an electrical plug connection or an inductive charging port
In both cases, UWB is again the key, as the positions of the corresponding charging plugs and sockets or induction surfaces have to connect precisely. Initially, this involves autonomous parking in the charging zone (public parking lot or home garage) and subsequent fine-tuning by the charging robot/charging station.
Use Case: UWB Tags and Device Localization
Where is the wallet, the keychain, the phone? Precise UWB localization can be used to locate lost personal items. They either have an integrated UWB node (e.g., in newer mobile phones) or a UWB tag is attached to the corresponding item. This functionality leads to two interesting use cases:
Item Finder:
An UWB system in your car, home or in a public space like an industrial facility or a parking garage can locate UWB-tagged items. A user interface makes the location results accessible. Typically, a mobile app (e.g., in the parking garage, see figure on the right) is suitable, but in some use cases like hospitals or industrial facilities a web interface is possible (user terminal, e.g., locating work equipment). In the case of the car, the integrated car infotainment system or the graphical HMI is particularly suitable. You will never be late again because you spent too long searching for your house keys.
Item Reminder:
How often do you drive to work and halfway there, you realize your mobile phone is still in the bathroom? Or you are standing in front of your company and can’t get in because your access card was left at home? Tagging important items like keys, wallet, access card, or mobile phone (where the UWB node may already be integrated) allows your car to automatically remind you when something is missing as you start driving. Forgotten access cards or phones are a thing of the past.
Use Case: Private Garage Parking
By equipping the private garage with UWB anchor points, the parking process can be supported or even initiated automatically. The high localization accuracy of UWB ensures that the vehicle can be safely parked even in tight spaces.
Use Case: Automated Valet Parking (AVP)
A lot of time is spent in city centers or at the airport, parking and retrieving your car. With UWB, this scenario can be a thing of the past.
Similar to the private garage, UWB localization can be used for autonomous driving/parking. The parking facility requires appropriate equipment with UWB anchors and a guiding software for the cars. Then, only one drop-off and pick-up area is needed. The UWB-equipped cars follow the route precisely as dictated by the UWB system and park securely. Stress and wait times at the entrance of the parking garage can thus be avoided.
Use Case: Reference Localization on Test Tracks
You are a car manufacturer and have been working on fully automating your production for years. But what about the test drive or the transfer from production area A to B? Does the car have to be driven manually, or can the test drive or transfer take place autonomously?
UWB makes an unmanned test drive on a UWB-equipped test track possible, analogous to the use case of the automated car park. If you think that the test driver also has other functions, such as recognising fault-signalling noises during the test drive, then we recommend talking to Embedded AI. The automatic recognition of acoustic signals is also one of our core competences. We are sure to find a suitable solution here.
Related Automotive Platform: X-UWB™
For automotive applications, UWB localization can become part of a broader platform approach. Our X-UWB™ concept combines localization, in-cabin sensing, and software-defined vehicle functions based on UWB technology.
Are you interested in UWB localization?
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