iPhone开发-辅助GPS
iPhone 的 GPS 是怎么回事？当我在办公楼或房间里时，我从来没有好好读书。到底是什么东西在打勾呢！什么不是？请帮助我了解辅助 GPS 科学。
What's the deal with iPhone's GPS? I never get a good reading when i'm in my office building, or in my room. What really ticks it! and what doesn't? Please help me understand the assisted GPS science.
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如果我没记错的话，GPS 会尝试使用三种方法来确定您的位置：
1. 卫星
2. 移动网络
3. Wi-fi 网络
因此，如果您没有良好的阅读能力，那么这些方法中的一种或多种可能无法在您所在的地区正确使用。例如，卫星在墙壁和天花板较厚的建筑物中并不总是能很好地工作。
If I'm not mistaken, the gps tries to pinpoint your position using three methods:
1. Satellite
2. Mobile network
3. Wi-fi networks
So if you don't have a good reading, then probably one or more of these methods cannot be used properly in your area. For instance, satellite will not always work that well in buildings with thick walls and ceilings.
辅助 GPS 意味着它可以从不同于 GPS 卫星的不同来源获得位置，例如已知的 WiFi 热点或 GSM 桅杆。然而，这些来源的准确度不如真正的 GPS。
克劳斯
Assisted GPS means that it may have it's location from different sources than GPS satellites, for instance known wifi hotspots, or GSM masts. However these sources are less accurate the true GPS.
Claus
为了使 iPhone 中的实际 GPS 获得良好的位置，它必须位于 GPS 卫星的直接视线范围内。它不能在建筑物内做到这一点。因此，如果您在室内，您将无法通过 iPhone 获得最佳位置。它可以使用其他方法（例如手机网络和公共 Wi-Fi 网络）为您提供位置，但这些位置不如真实 GPS 位置准确。
这是一篇解释 GPS 系统的文章：
http://en.wikipedia.org/wiki/Gps< /a>
For the actual GPS in your iphone to get a good position, it has to be in direct sight of the GPS satellites. It cannot do that inside a building. So if you are inside you are not going to get the best position from the iphone. It can give you a position using other methods such as the cell phone network and public wi-fi networks, but these positions aren't as accurate as the real GPS position.
Here is an article that explains the GPS system:
http://en.wikipedia.org/wiki/Gps
取决于谁对辅助 GPS 的定义。
真正的“辅助 GPS”意味着 GPS 接收器使用来自蜂窝塔位置的已知初始位置来引导 GPS 位置计算。如果您知道自己在哪里，位置解决方案锁定信号的速度就会快得多 - 这就是为什么与更新相比，GPS 需要很长时间才能找到首次定位。
一些 API 使用辅助 GPS 作为替代定位服务的简写，如果 GPS 不可用、被禁用或使用过多的电池电量，它将根据蜂窝塔三角测量或其他方法提供较低等级的位置。
Depends on whose definition of Assisted GPS.
True 'assisted GPS' means the GPS receiver uses a known initial position, from the cell tower location, to bootstrap the GPS position calculations. If you know where you are it's much quicker for the position solution to lock to the signal - that's why GPS take so long to find first fix compared to updating.
Some APIs use assisted GPS as shorthand for alternate location services where if GPS is not available, is disabled, or would use too much battery power it will supply a lower grade position based on cell tower triangulation or other methods.
我在 WWDC 2010 – Session 115 – Using Core Location in iOS 4 中找到了很多答案。
非常建议。
There are many answers I found in WWDC 2010 – Session 115 - Using Core Location in iOS 4.
Very advised.