Ultra-Wideband Technology: Turning Smartphones into Digital Car Keys

BIS Research
6 min readMay 2, 2023


Turning Smartphones into Digital Car Keys
Turning Smartphones into Digital Car Keys

Advancements in communication and automotive technology have taken the world by storm with significant software and hardware developments.

Smartphones have become an inseparable part of our routine lives and serve a greater purpose than just communication and entertainment.

Now, smartphones can be used as digital car keys. This has been enabled by ultra-wideband (UWB) technology which makes it easier and more convenient for users to access their vehicles.

UWB technology is a short-range wireless communication protocol that can accurately locate objects in three-dimensional space using radio waves. This makes it ideal for use in keyless entry systems and other applications such as indoor navigation and asset tracking.

UWB technology detects, verifies, and authorizes access to the owner of the vehicle, making it virtually impossible for unauthorized users to gain access to the vehicle.

This article explores ultra-wideband (UWB) technology and its role in converting smartphones into digital car keys.

Ultra-Wideband (UWB) Access Powering Digital Car Keys

Ultra-wideband (UWB) technology-based digital key vehicle access is a new way of unlocking and starting a car without the need for a physical key.

This technology uses UWB’s high-precision spatial positioning capabilities to ensure that the driver’s smartphone is in close proximity to the vehicle before allowing access.

To use UWB digital key vehicle access, the driver first pairs their smartphone with the vehicle’s in-built computer. Once the phone is paired, the UWB sensors in the car can detect its location in three-dimensional space, allowing the vehicle to determine whether the phone is inside or outside the car and how close it is to the vehicle.

Moreover, in order to start the vehicle, the driver can place their paired smartphone in the designated phone holder or console and press the start button.

UWB technology provides a high level of security as it is difficult for unauthorized users to gain access to the car without the paired smartphone.

UWB technology’s high-precision spatial positioning capabilities also help prevent accidental locking or unlocking of the car, ensuring that only the authorized user has access.

Furthermore, UWB digital key vehicle access allows for remote control of certain functions, such as unlocking the car from a distance, adjusting climate control settings, or even parking the car remotely.

This provides greater convenience for drivers and can also improve accessibility for individuals with disabilities.

Although UWB technology offers numerous advantages, users may still prefer the familiarity of traditional physical keys, along with some older vehicles being incompatible with this technology.

Nonetheless, as UWB technology continues to improve and become more widely adopted, it is likely to become an increasingly popular feature in modern mobility, such as automated and connected vehicles.

Moreover, UWB technology is being widely adopted for car rentals or shared mobility, which could lead to a more sustainable and efficient transportation system.

Using UWB technology, car owners can grant access to their vehicles for a specified period of time to renters who need to make short trips.

Through this arrangement, car owners can earn extra income while offering drivers the convenience of using a car for short periods without the expense of ownership.

Thus, UWB technology is increasingly being integrated into high-budget smartphones and luxury cars. For instance, Apple and Android have developed their own digital car key access software.

Moreover, high-end automotives brands such as BMW, General Motors, and Mercedes have already begun to offer ultra-wideband technology-based vehicle access.

This trend of automation of vehicle access is driving growth in the market of UWB technology.

According to data insights from BIS Research, the global ultra-wideband technology-based vehicle access control market was valued at $92.6 million in 2022, which is expected to grow at a CAGR of 17.09% and reach $383.1 million by 2031.

Ultra-wideband technology-based vehicle access control market

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How does UWB technology recognize the digital car key?

Ultra-wideband (UWB) technology widely utilizes two methods for recognizing a digital car key, i.e., time difference of arrival (TDoA) and two-way ranging (TWR).

1. Time Difference of Arrival (TDoA)

The time difference of arrival (TDoA) method is a technique used to locate tags within a certain venue. Tags are devices that emit signals and are typically attached to objects that need to be tracked.

This method is highly scalable and energy-efficient because tags only need to transmit once during the process, which prolongs their battery life.

Multiple anchors are strategically placed in fixed locations throughout the venue and are precisely timed to receive signals from the tags.

When a mobile device, such as a smartphone, emits a signal, each anchor that receives it records the time of arrival using a common synchronized time base.

The timestamps from multiple anchors are then sent to a central location engine, which uses multilateration or hyperbolic positioning algorithms to determine the location of the mobile device based on the time differences between each anchor.

This allows for the accurate determination of the device’s 2D or 3D position within the venue, allowing the UWB system to recognize the digital car key’s location.

2. Two-Way Ranging (TWR)

The TWR method determines the distance between a tag and an anchor by measuring the time it takes UWB radio frequency signals to pass back and forth between them (Time of Flight or ToF) and multiplying that time by the speed of light.

This method is used for secure and accurate distance determination in applications such as a keyless car entry system. The tag sends a poll message with the known address of an anchor, and the anchor logs the time it receives the poll message and responds.

The tag then determines the signal ToF using the signal round-trip time (Tround) and the time it took the anchor to process and respond to the initial poll message (Treply).

By multiplying the ToF by the speed of light, the tag calculates the distance and can pass the calculated distance to the anchor in a final message.

This process is repeated with multiple anchors to triangulate the position of the tag. In the case of a digital car key, the position of the tag corresponds to the location of the driver’s paired smartphone.

By using encrypted communication between the digital car key and the vehicle, UWB technology ensures that only authorized users can gain access to the vehicle.

Moreover, the high accuracy of TWR ensures that the vehicle will only unlock when the digital car key is in close proximity, adding an extra layer of security to the system.

How is authentication ensured for UWB-enabled automatic access?

Authentication is the process of verifying the identity of a user or entity attempting to access a system or resource. It is a security mechanism used to ensure that only authorized users are granted access to sensitive or protected information.

Authentication is an essential component in providing automatic access through UWB technology. Two major types of authentications are required in this domain, i.e., biometric and non-biometric.

Biometric authentication verifies a person’s identity by examining unique physical or behavioral characteristics. Data provided by the user is compared with validated user information stored in a database, which is defined as physical or behavioral traits.

For instance, facial recognition, fingerprint recognition, eye recognition, and voice recognition are biometric authentication methods.

Moreover, non-biometric security measures rely on software systems to validate a user’s identity.

Non-biometric authentication, such as callback modems, logs a user off a network and calls them back at a predetermined or a number logged in the records to confirm their identity.

Moreover, non-biometric methods such as firewalls filter all incoming network traffic, preventing unauthorized access from both websites and individuals and intrusion detection systems (IDS) supplement firewalls by detecting and forecasting threats such as denial-of-service attacks.


The future of UWB-enabled digital key vehicle access looks bright as automakers and technology companies continue to invest in the technology.

UWB-enabled digital key access has the potential to integrate with other smart car technologies, such as autonomous driving and vehicle-to-vehicle communication, making it an attractive option for automakers.

Moreover, UWB technology requires specialized hardware and software, which may not be present in all vehicles or in all locations.

However, as UWB technology becomes more mainstream, we can expect to see more widespread adoption of the technology, along with the necessary infrastructure to support it.

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