iPhone GPS: How It Works And How To Set It Up

The iPhone's GPS and location technology powers many useful apps. Apple

How does your iPhone know where you are, and how do you set up all of your iPhone's location technology to be most useful to you, while protecting your privacy?

Having a thorough understanding of your iPhone's GPS and location technology will help you get the most from your device and give you the insights you need to make the many apps on your phone that tap into location technology perform well and conserve battery life.

The iPhone actually has six different but complementary technologies on board to master location.

GPS is short for the Global Positioning System, which is a satellite constellation and support infrastructure put in place and maintained by the U.S. military. GPS finds your position by trilateration of satellite signals. This is a strength because it works world-wide. One weakness of GPS is that its signal does not penetrate buildings, deep woods, or canyons (including urban skyscraper canyons) very well.

Accelerometer & Gyroscope
The iPhone has an amazingly small 6-axis gyroscope and accelerometer combination chip on board made by InvenSense. The gyroscope tells how your phone is oriented at all times. The accelerometer detects and records motions big and small as inputs the phone's other processors may use.

WiFi Tracking
When GPS doesn't work well, such as inside buildings or among tall buildings, WiFi tracking can replace or supplement it.

WiFi tracking uses a database of WiFi networks around the world to triangulate your position based on multiple WiFi signals.

Your iPhone also has a digital compass as part of its InvenSense motion-tracking chip. The compass is used to supplement other motion technologies, and to orient any map that you happen to be using.

The compass comes into play, for example, when you tap the Google Maps arrow to orient a map. The Compass may also be used on its own via many useful and in-depth compass apps.

You might think of a barometer, which measures air pressure, as primarily a weather-prediction device. It's not used for that purpose on an iPhone, however. The barometer helps supplement the GPS chip for measuring elevation changes, creating more accurate elevation and elevation-change readings.

M8 Motion Coprocessor
In the iPhone, Apple uses its own M8 Motion Coprocessor chip to "continuously measure data from the accelerometer, compass, gyroscope, and a new barometer," states Apple. "This offloads work from the A8 chip for improved power efficiency. And now those sensors do even more, measuring your steps, distance, and elevation changes."

Managing iPhone Location Technology
Over the years, Apple has simplified user management of location technology, but you still need to know where to look to take control of your apps and maximize battery life.

Settings / General / Restrictions
You may enable Restrictions with your passcode. You may literally turn off all location technology on the iPhone (not recommended) by toggling off "Location Services." Rather than doing that, take a look at the long list of apps below "Share My Location." You may set them to never, while using, or always.

The point is, you can take control of which apps use your location data and how with these customized settings.

Settings / App List
Under Settings, you may also control apps' access to your location services. Simply scroll down to the app list, then tap on the app icon to see how it interacts with your phone. You may toggle on or off various settings, depending on the app, including Location, Notifications, Use Cellular Data, access to your Calendar or Contacts, and more.

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