Superior Cars Using UWB Technology

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Superior Cars Using UWB Technology [Copy link]

Imagine a wireless communication technology for distance and positioning that is compact and cost-effective, while also providing centimeter-level accuracy in real time. That's ultra-wideband technology (UWB).

introduction

Wireless positioning/distance sensing and secure communications are the backbone of emerging automotive systems for convenience, performance, security and safety for consumers and fleets. The demand for autonomous driving and enhanced driver assistance features continues to increase. However, the familiar short-range relative position sensing technology has limitations in automotive applications, the most obvious of which are:

• Latency/Position Update Rate

• Positioning accuracy, and

• Security with included communication features

A recently repurposed technology, ultra-wideband (UWB), promises to significantly enhance short-range relative position sensing capabilities, ensure secure communications between vehicles, and enable the development of many advanced automotive features that were previously not feasible.

What is UWB?

Ultra-wideband technology (UWB) is a wireless standard based on IEEE 802.15.4z that is designed to provide precise positioning and secure communications. UWB outperforms many existing wireless standards in terms of reliability, positioning accuracy, positioning latency/update rate, and security, and is both affordable and compact. In addition, due to the nature of the UWB physical layer protocol, UWB communications and location sensing are immune to multipath and interference, while achieving low energy consumption (Figure 1).

How does UWB work?

UWB uses ultra-wide bandwidth and short pulses (about 2 nanoseconds) with very steep rise/fall times to encode data using binary phase shift keying (BPSK) and/or pulse position modulation (BPM). UWB uses two consecutive pulsed radio (IR) signals to represent a symbol, and the IR signal can occupy a chip interval (Tc) within a time frame (Tf). Time hopping codes are used to determine the exact position of the signal within a specific time frame, thereby minimizing the chance of interference between UWB systems (Figure 2).

Figure 2: Ultra-wideband uses sequences of extremely narrow, short pulses to transmit information.

Each UWB communication is time-stamped. The time-stamp allows the distance between two radios to be calculated using the time of flight (ToF) of the signal between the two radios, i.e. point-to-point (P2P) two-way ranging (TWR).

This method of measuring the distance between two UWB communicating radios is not only unique and secure, but is also immune to multipath, since the shortest path is always the shortest distance between the two radios.

By further extending this concept to include additional anchors distributed throughout the environment, real-time navigation can be achieved. With multiple synchronized anchors in space, the exact position of the tag in 3D space can be determined using either Time Difference of Arrival (TDoA) or Reverse TDoA (RTDoA).

Assume that the UWB tag is equipped with multiple antennas. In this case, by determining the range and orientation of the communicating radios, the relative position of the two devices can be calculated using the Phase Difference of Arrival (PDoA).

Overview of Current Positioning Technologies

There are currently five methods for distance/position measurement using modern wireless communication technologies: RFID, Wi-Fi, Bluetooth, GPS, and UWB. RFID, Wi-Fi, and Bluetooth use RSSI to calculate distance. RSSI is a measure of the relative signal strength between the transmitting and receiving radios, and can be used to roughly estimate distance given specific channel information. Another method is GPS, which measures ToF between the user equipment (UE) and multiple time-synchronized satellites, which can be used to calculate the 3D position relative to the satellite constellation. Finally, there is Qorvo's IR UWB ToF technology (Figure 3).

The main difference between these approaches and Qorvo IR UWB ToF is that the UWB approach uses very high bandwidth frequency signals that are transmitted very briefly. Narrowband ToF systems use short pulses that are transmitted over only a narrow frequency band. Wi-Fi, Bluetooth, and RFID also use ToF, but they are limited in bandwidth and cannot generate very short pulses with fast rise/fall times (sharp edges) compared to UWB (Figure 4). The ultra-wide bandwidth of UWB means that the signal energy is spread across an ultra-wide frequency band, which means that at any given frequency, the protocol is relatively immune to interference. This very fast rise/fall time, along with the short UWB pulse duration, minimizes the effects of multipath interference and enables very precise time measurements, resulting in improved accuracy.

Figure 3: Comparison of various wireless positioning and communication standards.

Figure 4: Distance/location measurement comparison between RSSI, Wi-Fi, Bluetooth, narrowband ToF, and Qorvo IR UWB ToF.

That’s why UWB can achieve centimeter-level accuracy between two devices at relatively long distances compared to Bluetooth, Wi-Fi, and RFID. In addition, the UWB communication protocol has a maximum throughput of 27Mbps, which is higher than all other protocols except Wi-Fi. The extremely short pulses and fast distance/position calculations mean that UWB can perform real-time distance/position tracking at sub-millisecond speeds suitable for 3D tracking, which is about 100 times faster than GPS. In addition, UWB tags and anchors are low-cost and power-efficient, enabling massive scalability of protocol and hardware support.

UWB for Automotive Applications

It’s no surprise that traditional remote keyless entry (433MHz car dongles/key fobs) isn’t the most secure solution for preventing unwanted entry to your car. Some known exploits of these devices can sometimes allow access or even control of the car. As a result, the Car Connectivity Consortium (CCC) has developed a new standard that leverages UWB technology to create a more secure remote keyless entry solution.

In fact, CCC’s UWB standard uses the same type of security protection as credit cards. Automakers in the United States, Japan, and the European Union have already begun adopting this UWB standard, and have been encouraging Chinese automakers to do the same. In the third quarter of 2018, CCC began adopting High Rate Pulse UWB (HRP-UWB), a technology that will increase interoperability between automotive and mobile manufacturers, allowing mobile devices to be used as remote control keys.

The first use case for automotive UWB is Passive Entry/Passive Start (PEPS), which uses NFC technology at Phase 2 of the CCC's PEP program for access control systems, and UWB and Bluetooth Low Energy (BLE) at Phase 3.

UWB radar technology is so sensitive that it can be used to detect human breathing…

Another use case is short-range radar using UWB, which can meet new safety requirements by detecting people and objects inside and outside the vehicle, such as intrusion and passenger detection or easy trunk entry. UWB radar technology is so sensitive that it can be used to detect human breathing and even distinguish between adults and infants. This not only helps prevent children and infants from being left behind in the car, but can also alert the driver protection system if the driver falls asleep or becomes incapacitated.

UWB radar technology is so sensitive that it can be used to detect human breathing…

Another use case is short-range radar using UWB, which can meet new safety requirements by detecting people and objects inside and outside the vehicle, such as intrusion and passenger detection or easy trunk entry. UWB radar technology is so sensitive that it can be used to detect human breathing and even distinguish between adults and infants. This not only helps prevent children and infants from being left behind in the car, but can also alert the driver protection system if the driver falls asleep or becomes incapacitated.

Figure 5: Emerging and potential future automotive UWB use cases.

Another use case for UWB is to ensure the safety of automatic wireless charging of electric vehicles. This feature can drive a UWB electric vehicle into a wireless charging area, then automatically share credentials and complete the charging transaction (Figure 5).

Automotive UWB Hardware and Software

Digital Key (DK) car access is the first emerging automotive UWB application that not only connects a UWB-enabled phone to a UWB-equipped car for remote keyless access, but also provides increased security. Through an authorized server, DK technology provides mobile phones with car access using private keys. The initial key exchange is done between the phone and the car’s secure element (SE), enabling automatic car access without a cloud connection (Figure 6).

Using a high-end car as an example of a PEP system, a mobile phone or key fob equipped with the required UWB, BLE, NFC, and electronic SE (eSE) devices (pre-configured) can be used to access a car also equipped with compatible hardware and SE. In this example, each UWB transceiver (TRx) in the car (also called a UWB anchor) has a coverage circle that allows secure access as long as a BLE signal exchange is performed (Figure 7).

Figure 6: PEPS high-end automotive hardware example

Figure 7: Example of PEPS automotive hardware implementation.

As long as the BLE system performs network discovery and UWB wake-up functions, UWB ranging and security verification will trigger the CAN bus system in the car to start the automatic remote keyless entry mechanism. Multiple UWB anchor points in the car can achieve precise positioning detection of mobile phones or remote control keys, and some security features can be added. Remote control keys or mobile phones equipped with eSE and NFC as a backup system can also enter such vehicles when they are close to the car's NFC tag.

UWB and V2V

By adding additional UWB sensors and combining UWB ranging with vehicle-to-vehicle (V2V) communication links, we can leverage V2V to pass UWB information to create a UWB area network. This allows vehicles to share safety information between each other and assist fully or semi-autonomous driving or navigation systems with safety coordination and obstacle avoidance, or otherwise alert manually driven cars (Figure 8).

Figure 8: Sensor fusion capabilities using UWB and V2V communications.

Figure 9: Comparison of commonly used automotive sensors.

The accuracy, reliability, and fast update rate of UWB enable very rapid reactions between vehicles. In some cases, UWB can even replace more expensive and computationally complex camera systems for vehicle coordination and obstacle detection (Figure 9).

in conclusion

There is a gap in the capabilities of currently deployed automotive sensor technologies. Fortunately, recent advances in wireless sensor technology are closing this gap by enabling low-cost, high-update-rate, and very accurate compact distance/location sensing solutions, as well as relatively high data rate communications. UWB promises a host of potential applications, from V2V communications to passenger safety sensing. The best technology is not here yet, as UWB technology will continue to advance in the future as it becomes widely available and integrated into cars and smartphones.

For more information about UW, please refer to the detailed document RF Technology Research Center

dwdsp

I have used UWB, but the disadvantages are that it must be unobstructed, it consumes a lot of power, and the error is about 10cm

laker2008

Um, really? This flaw is really hard enough.

btty038

laker2008 posted on 2023-3-22 09:44 Uh, really? Then this flaw is really "hard",

Let's look at the advantages first.

btty038

dwdsp posted on 2023-3-22 08:53 I have used UWB. The disadvantages are that it must be unobstructed, the power consumption is high, and the error is about 10cm

Radio basically needs to be used without any obstruction. Without popularization, there will be no more optimization. Personal opinion