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Hello GPS

This is a very simple location diagnostic application used primarily by us to diagnose what the location subsystem of a BlackBerry 10 device is doing. The location subsystem in BlackBerry 10 is quite sophisticated and capable of deriving location data from the cellphone carrier network signals, Wi-Fi access point signals (the system does not need to be connected to the Wi-Fi network to get location data), from the US Navy Global Positioning System (GPS) and from the Russian Global Navigation Satellite System (GLONASS). 

The program simply displays the data available from the locations subsystem without modification except for the actual geographic location data. The location subsystem provides degrees Latitude and Longitude as double precision floating point numbers. Hello GPS translates those numbers in to one of three coordinate formats:
  • Degrees, Minutes and Seconds (DMS)
  • Universal Transverse Mercator (UTM)
  • Military Grid Reference System (MGRS)
The precision of these displays may be selected to be 1 degree to 0.01 second, or 100 km to 0.1 meter.

Hello GPS is also capable of looking up the place name associated with the current location using either a database provided by BlackBerry or Google.

GPS

The main page displays a constellation plot showing the relative azimuth, elevation and identification number of each satellite in view. Satellites that are being used in the
computation of the position are colored blue, those that are not being used are colored red. There is also a bar graph area that shows the received signal strength of each satellite in view. Finally there is a text display area that contains:
  • The date and time of the last valid fix in universal coordinated time
  • The source of the fix (eg. network or gps)
  • The fix location in the format selected on the settings page
  • The Horizontal Dilution of Position (HDop), essentially the horizontal accuracy of the fix in meters
  • The altitude of the fix in meters above mean sea level
  • The Vertical Dilution of Position (VDop), essentially the vertical accuracy of the fix in meters
  • The direction of travel (heading) in degrees relative to true north
  • The speed of travel in meters per second
  • When stationary the position shown is an average over 20 fixes. The individual fixes are displayed by a yellow line superimposed over the constellation plot.

Map

Maps are available from BlackBerry Maps and Google Maps. The map from the source selected in options may be brought up by a long press on the location display. Each specific source may be selected from the application menu. The BlackBerry Maps display is rotated by the compass sensor. A compass needle is displayed in the bottom left corrner and the digital heading in the upper right.

The Google Maps display is the Google Maps mobile web application.

Both map displays are constructed to provide as much of the screen for map data as possible. The maps can be dismissed in two ways:
  • A long press on the back arrow button in the lower right will close the map.
  • A short press on the back arrow button will bring up the action bar. The back button will close the map, but the suspend button will return the user to the main display but leave the map active so the user may return to it later.

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