如何在移动设备上在室内使用GPS？ [英] How to use GPS indoors on a mobile device?
问题描述
我是移动应用程序的新手。基本上我想让用户的GPS坐标在室内。
我在户外探测移动设备没有任何问题，只有在室内给我带来麻烦时。
我曾尝试设置准确性，但无济于事。
是否有解决方案？
<这是我的代码：
new Thread（）
{
public void run（）
{
尝试
{
Criteria cr = new Criteria（）;
cr.setHorizontalAccuracy（1000）;
LocationProvider lp = LocationProvider.getInstance（cr）;
位置l = lp.getLocation（60）;
坐标c = l.getQualifiedCoordinates（）;
if（c！= null）
{
lat = c.getLatitude（）;
lon = c.getLongitude（）;
catch（Exception e）
{
System.out.println（Error）;
}
}
} .start（）;
GPS基于从卫星发射到您的距离接收器。您的GPS接收器需要（一般来说）来自至少4颗卫星的信号才能够计算其位置。开阔天空条件下L1频段的信号电平大约达到-130dBm。商用接收机，如集成在移动电话中的接收机，能够跟踪低至-160dBm的卫星。在此阈值下，接收器无法使用该信号。这30dB的余量允许从树叶，玻璃窗，甚至是轻质墙壁等障碍物中衰减一些信号，但几个建筑物楼层完全遮蔽几乎所有方向的信号，导致GPS完全无法使用。即使衰减允许接收器使用信号来计算其位置，所达到的精度可能不足以满足您的目标应用（精度因信号衰减而降低）。
$ b另一方面，Skyhook等Wi-Fi定位系统（在许多移动平台上实现）通常能够计算建筑物内部的位置，但该方法面临两个主要缺点：$ b
$ b
- 数据库覆盖范围不包括室内网站（AFAIK），因此
返回的位置非常接近
，不可用于任何应用程序。
- Wi-Fi定位算法基于对使用信号电平的热点进行距离估计，受室内障碍（人员，家具等）的影响非常大。这会降低定位精度。
还有第三种选择：将MEMS chpset中的加速度与手机中的加速度已知的GPS位置。这可能在某些情况下工作......
总之，手机室内定位没有现成的解决方案，但有些人正在研究这个主题（例如 http://www.polestar.eu/en/node/111/y）
编辑：我忘记提及基于蜂窝塔的定位，只要手机对蜂窝网络进行了主动数据纠正，就可以使用该定位。这种方法只有足够的准确性才能给移动电话所在的城市。
I am new to mobile applications. Basically I want to get the user's GPS coordinates indoors. I have no problem detecting the mobile device outdoors, only when indoors it is giving me problems. I have tried setting the accuracy, but no avail.
Is there a solution to it?
Here is my code:
new Thread()
{
public void run()
{
try
{
Criteria cr= new Criteria();
cr.setHorizontalAccuracy(1000);
LocationProvider lp= LocationProvider.getInstance(cr);
Location l = lp.getLocation(60);
Coordinates c = l.getQualifiedCoordinates();
if(c != null )
{
lat = c.getLatitude();
lon = c.getLongitude();
}
}
catch(Exception e)
{
System.out.println("Error");
}
}
}.start();
GPS is based on range estimates from emitting satellites to your receiver. Your GPS receiver needs (in general) signal from at least 4 satellites to be able to compute its location. Signal levels for the L1 band in open sky conditions approximately reach -130dBm. Commercial receivers, such as those integrated in mobile phones, are able to track satellites down to -160dBm. Under this threshold, the receiver is not able to use the signal. This 30dB margin allows for some attenuation from obstacles such as foliage, glass windows, even light walls, but several building storeys completely mask signals from almost all directions, making GPS completely unavailable. And even if the attenuation allows the receiver to use the signals to compute its positions, the accuracy achieved probably won't be sufficient for your target application (the accuracy is degraded by signal attenuation).
On the other hand, Wi-Fi location systems such as Skyhook's (implemented on many mobile platforms) are often able to compute a location inside of buildings, but this method faces two main drawbacks:
- The database coverage does not include indoor sites (AFAIK), so the returned location is very approximate and unusable for any application.
- The Wi-Fi location algorithms, based on range-estimation to hotspots using signal levels, is affected very much by indoor obstacles (people, furniture, etc.). This decreases the positioning accuracy.
There is a third option : integrate the acceleration from the MEMS chpset in the mobile phone, from the last known GPS position. This might work under certain conditions...
In conclusion, there is no off-the-shelf solution for indoor location in mobile phones, but some are working on the subject (e.g. http://www.polestar.eu/en/node/111/y)
Edit : I forgot to mention cell-tower based positioning, which is available as long as the phone has an active data correction to the cellular network. This method is only accurate enough to give the city where the mobile phone is located.
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