介绍
When it comes to RTLS (实时定位系统) 和IPS (室内定位系统) 解决方案, 其中一项杰出的技术是蓝牙到达角 (迎角). 现在, 引入了蓝牙通道探测,为设备之间的真实距离感知提供厘米级精度. AoA’s direction-finding capability significantly enhances indoor positioning and navigation solutions, making it ideal for real-time location services and proximity solutions. 另一方面, bluetooth channel sounding takes precision to the next level with centimeter-level accuracy utilizing Phase-Based Ranging and Round-Trip Time. What exactly are the differences between them? Understanding the strengths of both Bluetooth AoA and Channel Sounding will help you choose the best solution for your specific needs.
Understanding Angle of Arrival (迎角)
Working Principle of Angle of Arrival (迎角)
In the AoA (到达角) method, the device that needed to be determined direction with a single antenna sends a special direction finding radio signal to a receiving device. With multiple antennas arranged in an array, the receiving device can calculate the angle of arrival of the signal by measuring the slight time difference of arrival (时差) or phase difference of the signal at each antenna. If there is a system covering multiple locators, it can combine the AoA data from different locators to triangulate the position of the signal transmitter exactly.
The Benefits of Angle of Arrival (迎角)
Before the Bluetooth AoA and AoD capability was introduced, 接收信号强度指数 (Received Signal Strength Indicator) stood out as the solution for device distance calculation. RSSI determines the distance between the signal source and the receiving device by the strength of the wireless signal. 因此, positioning is not accurate in highly obstructed areas where the signal strength can easily be weakened. Adding the AoA and AoD method to Bluetooth enhances positioning accuracy.
Precise Positioning: The AoA method can achieve sub-meter accuracy by calculating the angle at which signals arrive at the receiving device with multiple arrayed antennas.
实时追踪: By providing the precise direction of objects, the AoA method, when working with RTLS, allows for real-time updates of their direction and location.
The Limitations of Angle of Arrival (迎角)
An unavoidable problem in RF (无线电频率) wireless technology is signal attenuation during transmission. The AoA method faces the same issue as RSSI (Received Signal Strength Indicator), where accuracy can be affected by obstacles, reflections, and interference. 建筑物, 墙壁, and other structures can cause multipath effects, leading to errors in angle calculation. 然而, technologies and methods such as bluetooth channel sounding have been developed to address this challenge. 此外, calculating the angle of arrival involves complex signal processing and algorithms, which require powerful computing resources. That’s why the AoA typically requires a network-centric infrastructure.
The Applications of Angle of Arrival (迎角)
1.RTLS Solutions
AoA-supported solutions provide a sub-meter accuracy and real-time updates of location and direction, making them ideal for logistics and manufacturing, where they can accurately locate and track packages and materials.
2.IPS Solutions
The direction-finding capability of AoA greatly assists with indoor navigation. It can help navigate customers to the store and even to a specific shelf, providing a more seamless shopping experience.
3.近距离营销
Imagine customers pointing their AoA-supported smartphone at a product and promptly seeing specific details on the screen. It offers a more convenient and efficient way to shop and market products.
迎角 vs. AOD
Both the AoA and AoD methods have direction-finding capabilities. AoA measures the angle at which a signal reaches a receiver to determine the direction of a transmitting device, making it ideal for object tracking and real-time location systems. AoD measures the angle at which a signal leaves a transmitter, enabling a receiving device to calculate its own location. Compared to AoD, AoA is less complex and more widely used.
了解蓝牙通道探测
How Does Bluetooth Channel Sounding Work?
Bluetooth channel sounding utilizes PBR (基于相位的测距) 和RTT (Round-Trip Time) to determine the distances between Bluetooth-connected devices with unmatched centimeter-level accuracy. Combining the use of PBR and RTT enhances security by cross-checking.
策略性BR: In Phase-Based Ranging (策略性BR), an initiator device sends a signal to a reflector device, which receives and reflects the signal back to the initiator. The initiator device then measures the phase offset or difference between the transmitted and received signals, allowing for accurate distance calculation between the two devices by estimating this phase difference.
实时传输时间: In the Round-Trip Time (实时传输时间) method, the initiator device sends signals to the reflector device, which returns the signals. The distance between the two devices is estimated by assessing the time of flight (飞行时间), which is the time it takes for the packets to travel back and forth. RTT is regarded as a highly secure method.
The Benefits of Bluetooth Channel Sounding
准确性
Bluetooth channel sounding uses PBR (基于相位的测距) to measure distances up to about 150 遇到距离模糊之前的米. 通过结合RTT (往返时间) 与策略路由, 应用程序可以检测并解决这种歧义, 允许在更大范围内进行更准确的距离测量.
安全
距离测量解决方案特有的安全问题通常涉及不可信设备欺骗可信设备的风险,使其相信另一个可信设备足够接近以允许采取或授权某些操作.
The combined use of PBR and RTT is one of bluetooth channel sounding’s strategies to counter this threat. 由于这两种方法的工作原理完全不同, 两者同时受到攻击或操纵以产生误导性结果的可能性极低. PBR和RTT交叉校验的高安全性为开发者提供了更大的可能性.
The Limitations of Bluetooth Channel Sounding
1.Complexity
The process of channel estimation and signal processing can be computationally demanding, especially for devices with limited processing capabilities.
2.功耗
The accuracy of channel sounding depends on the transmission power of the Bluetooth devices involved. Higher power consumption can be a concern for battery-powered devices.
3.Environmental Impact
In complex environments with obstacles and reflections, the accuracy of channel sounding can also be affected.
The Applications of Bluetooth Channel Sounding
1.’Find My’ 解决方案
For the end-user of Bluetooth ‘Find My’ solutions, 这是最普遍的低功耗无线技术, it is easier and faster to locate lost items, whether by direction or distance.
2.Digital Key
在数字钥匙解决方案中, bluetooth channel sounding can enhance security and user experience by ensuring that a lock only opens when the authorized device is within a certain distance.
3.Indoor Positioning with Centimeter-Level Accuracy
Channel Sounding offers fine ranging that may transform RTLS solutions, such as more precise package tracking in logistics and supply chain, and quicker responses to patient calls or emergencies in healthcare and hospitals.
Bluetooth channel sounding offers exceptional technical flexibility in terms of security, 准确性, 和延迟. 这为开发人员提供了最大的创新自由, enabling the creation of endless possibilities between 蓝牙设备 and paving the way for a more wireless and connected world.
The Differences Between Angle of Arrival and Bluetooth Channel Sounding
AoA/ AoD | 蓝牙信道探测 | |
---|---|---|
Measurements | Estimates the angle of incoming (迎角) and outgoing (AOD) signals | Uses PBR and RTT for fine ranging |
Complexity | AoA is simpler; AoD is more complex and less frequently used | Less complex, simpler implementation |
准确性 | Capable of sub-meter accuracy but can be hindered by multipath propagation | Centimeter-level accuracy even in multipath environments |
Antenna Requirements | Requires multiple antennas to capture phase shifts | Multi-antenna not required, but can be used to enhance accuracy |
功耗 | 低功耗 | Slightly higher power consumption |
应用领域 | Direction finding capability for IPS and RTLS solutions | For fine ranging projects requiring high security |
Which is Good for You: Angle of Arrival and Bluetooth Channel Sounding?
两个都 蓝牙迎角 (到达角) 定位 and channel sounding offer ultra-high accuracy in location services. If you’re looking for a project that’s easy to scale, AoA is a better choice due to its maturity and widespread application. 此外, AoA’s direction-finding capability is very beneficial for indoor positioning, 导航, and proximity solutions. 然而, if your project demands extremely high precision in location services or places a high emphasis on security, bluetooth channel sounding is more suitable.