Question

My application uses gps location, but the request fails (time out error) every time if I stay inside of the building but location gets refresh well when I refresh the location from device Location Settings option if I stay in building too.

Here is my code

Criteria myCriteria = new Criteria();
myCriteria.setCostAllowed(false);
LocationProvider myLocationProvider = LocationProvider.getInstance(myCriteria);

Location myLocation = myLocationProvider.getLocation(((int)timeOutInMiliseconds/1000));
lastLatitude = myLocation.getQualifiedCoordinates().getLatitude();
lastLongitude = myLocation.getQualifiedCoordinates().getLongitude();
lastAltitude = myLocation.getQualifiedCoordinates().getAltitude();
lastAccuracy = myLocation.getQualifiedCoordinates().getHorizontalAccuracy();
lastSpeed = myLocation.getSpeed();

Please advise.

Ali

Answer 1

When you set the cost setting to false (myCriteria.setCostAllowed(false);), you set the GPS mode to be autonomous (the below table was taken from Location based services development guide – Criteria mapping properties.

Autonomous mode relies on GPS satellites only (see more about GPS modes here).

This mode uses the GPS receiver on the BlackBerry device to retrieve location information. This mode cannot be used indoors or in close proximity to many physical obstructions, and it can take several minutes to fully synchronize with four or more satellites for the first GPS fix.

That’s the reason why your request fails. Try using other GPS modes: assisted or cellsite.

---

Assisted mode

Assisted mode relies on GPS satellites and servers on the wireless network. This mode uses the wireless network to retrieve satellite information. This mode can achieve a fast retrieval of the first GPS fix.

For assisted mode use this snippet (it is worth noting that there are several assisted modes):

Criteria myCriteria = new Criteria();
myCriteria.setPreferredPowerConsumption(Criteria.POWER_USAGE_MEDIUM);
myCriteria.setHorizontalAccuracy(100);
myCriteria.setVerticalAccuracy(100);
myCriteria.setCostAllowed(true);

---

Cellsite mode

Cellsite mode relies on the geolocation service, or the wireless network to provide the location information of the current base station. This mode uses the wireless network to achieve the first GPS fix, and is generally considered the fastest mode. This mode does not provide BlackBerry device tracking information such as the speed and the bearing.

For cellsite mode use this snippet:

Criteria myCriteria = new Criteria();
myCriteria.setPreferredPowerConsumption(Criteria.POWER_USAGE_LOW);
myCriteria.setHorizontalAccuracy(Criteria.NO_REQUIREMENT);
myCriteria.setVerticalAccuracy(Criteria.NO_REQUIREMENT);
myCriteria.setCostAllowed(true);