什么是设备到 AP RTT
What is Device-to-AP RTT
我在浏览 Android Wifimanager class 时发现了这个方法：
public boolean isDeviceToApRttSupported ()
Returns
true if this adapter supports Device-to-AP RTT
但是什么是设备到 AP RTT？
RTT = 往返时间
= 信号从一台设备到另一台设备再返回的时间
仅从方法的名称来看，这应该可以回答是否可以（支持）测量 rtt 的问题。
推测：
这个答案更有可能是针对您的 android 设备及其 wifi-hotspot 功能给出的，而不是针对已连接的任何远程设备。
WiFi RTT (round-trip-time) 用于室内定位，包含在 Android P 预览中：https://developer.android.com/preview/features.html
Android P adds platform support for the IEEE 802.11mc Wi-Fi
protocol—also known as Wi-Fi Round-Trip-Time (RTT)—to let you take
advantage of indoor positioning in your apps.
On Android P devices with hardware support, your apps can use the new
RTT APIs to measure the distance to nearby Wi-Fi Access Points (APs).
The device must have location enabled and Wi-Fi turned on, and your
app must have the ACCESS_FINE_LOCATION permission. The device doesn't
need to connect to the APs to use RTT. To maintain privacy, only the
phone is able to determine the distance to the AP; the APs do not have
this information.
If your device knows the distance to 3 or more APs, the API uses a
multilateration algorithm to estimate the device position that best
fits those measurements. The result is typically accurate within 1 to
2 meters.
With this accuracy, you can build new experiences like in-building
navigation, fine- grained location-based services such as
disambiguated voice control (for example, "Turn on this light"), and
location-based information (such as "Are there special offers for this
product?").
我在浏览 Android Wifimanager class 时发现了这个方法：
public boolean isDeviceToApRttSupported ()
Returns true if this adapter supports Device-to-AP RTT
但是什么是设备到 AP RTT？
RTT = 往返时间 = 信号从一台设备到另一台设备再返回的时间
仅从方法的名称来看，这应该可以回答是否可以（支持）测量 rtt 的问题。
推测： 这个答案更有可能是针对您的 android 设备及其 wifi-hotspot 功能给出的，而不是针对已连接的任何远程设备。
WiFi RTT (round-trip-time) 用于室内定位，包含在 Android P 预览中：https://developer.android.com/preview/features.html
Android P adds platform support for the IEEE 802.11mc Wi-Fi protocol—also known as Wi-Fi Round-Trip-Time (RTT)—to let you take advantage of indoor positioning in your apps.
On Android P devices with hardware support, your apps can use the new RTT APIs to measure the distance to nearby Wi-Fi Access Points (APs). The device must have location enabled and Wi-Fi turned on, and your app must have the ACCESS_FINE_LOCATION permission. The device doesn't need to connect to the APs to use RTT. To maintain privacy, only the phone is able to determine the distance to the AP; the APs do not have this information.
If your device knows the distance to 3 or more APs, the API uses a multilateration algorithm to estimate the device position that best fits those measurements. The result is typically accurate within 1 to 2 meters.
With this accuracy, you can build new experiences like in-building navigation, fine- grained location-based services such as disambiguated voice control (for example, "Turn on this light"), and location-based information (such as "Are there special offers for this product?").