Why getBaseStationLatitude() keeps returning the Integer.MAX_VALUE (unknown)?

Question

Class project & thesis work - trying to pull information from CDMA Cell, specifically by using the getBaseStationLatitude() & getBaseStationLongitude(). The value being returned is the MAX_VALUE (2147483647) - I'm not receiving actual lat/longs. getBaseStationID(), getNetworkID() & getSystemID() are returning valid id's. I've tested this in 2 separate cells with no luck. My code is posted below. Both ACCESS_FINE_LOCATION & ACCESS_COURSE_LOCATION are added to manifest. Testing done on Droid, Android 2.2.2.

Questions - Has anyone run into same problems? Am I missing something in the code? Where are these values stored and issued at (e.g. are these coordinates assigned at the base station, and constantly being transmitted to mobile device)?

Code:

package xXx.edu.com;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.telephony.TelephonyManager;
import android.telephony.cdma.CdmaCellLocation;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class CDMAData extends Activity implements OnClickListener{

    CdmaCellLocation location;
    int cellID, lat, lon, netID, sysID;
    private Context context;
    Button getDataBtn;

   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);

      context = (Context) this;
      setContentView(R.layout.cid);

      setConnections();
   }

   private void setConnections() {

       getDataBtn = (Button) this.findViewById(R.id.getID);
       getDataBtn.setOnClickListener(this);

   }

   public void onClick(View v) {

       TelephonyManager tm = (TelephonyManager) context.getSystemService(Context.TELEPHONY_SERVICE);
       location = (CdmaCellLocation) tm.getCellLocation();
       cellID = location.getBaseStationId();
       lat = location.getBaseStationLatitude();
       lon = location.getBaseStationLongitude();
       netID = location.getNetworkId();
       sysID = location.getSystemId();

       TextView myView1 = (TextView) findViewById(R.id.bsID);
       myView1.setText("" + cellID);

       TextView myView2 = (TextView) findViewById(R.id.bsLat);
       myView2.setText("" + lat);

       TextView myView3 = (TextView) findViewById(R.id.bsLon);
       myView3.setText("" + lon);

       TextView myView4 = (TextView) findViewById(R.id.netID);
       myView4.setText("" + netID);

       TextView myView5 = (TextView) findViewById(R.id.sysID);
       myView5.setText("" + sysID);

   }
}

Fixed your code block for you, please use the code tags in the future — smith324, Mar 23 '11 at 19:03

score 1 · Answer 1 · edited Jan 20 '12 at 23:12

1

Here is why:

Latitude is a decimal number as specified in 3GPP2 C.S0005-A v6.0.It is represented in units of 0.25 seconds and ranges from -1296000 to 1296000, both values inclusive (corresponding to a range of -90 to +90 degrees). Integer.MAX_VALUE is considered invalid value.

Longitude is a decimal number as specified in 3GPP2 C.S0005-A v6.0. It is represented in units of 0.25 seconds and ranges from -2592000 to 2592000, both values inclusive (corresponding to a range of -180 to +180 degrees). Integer.MAX_VALUE is considered invalid value.

Say:

Latitude = L (integer as returned by Android cdma API)

Latitude in degree = (( L * 90)/1296000))

Now you can easily convert it to degree min and seconds: Following is the URL to do that(any of the following links should work): http://zonalandeducation.com/mmts/trigonometryRealms/degMinSec/degMinSec.htm

http://www.fcc.gov/mb/audio/bickel/DDDMMSS-decimal.html

edited Jan 20 '12 at 23:12

EboMike

76,846
14
164
167

answered Apr 03 '11 at 00:48

Manoj Monga

11
1

Thank you Manoj for the response. I might be mis-understanding your answer, but the problem I have is that running the code above, the value being returned to me is that which is represented by the Integer.MAX_VALUE ---> 2.1474836E9. That large number is what the API's are returning to me. I am not receiving a value between -1296000 to 1296000 or -2592000 to 2592000 for the lat & long respectively. I am not yet looking for the conversion math (which appears to be what you posted), but it will probably come in handy if I get this working! – bdzl10 Apr 04 '11 at 23:27
Hi Manoj, could you please point me to the source of the math you provided? – Feb 25 '12 at 05:53
I got it. They are located in `CdmaCellLocation.java`. Here is one of the files I found: http://hi-android.info/src/android/telephony/cdma/CdmaCellLocation.java.html – Feb 25 '12 at 06:09
To make this simpler, you can use (L / 14400) as the math. – mike47 Nov 01 '13 at 06:13

score 1 · Answer 2 · answered Dec 30 '11 at 19:13

Try calling the "CellLocation.requestLocationUpdate()" method before getting the location from the TelephonyManager. This will force the platform to update the cell location and should give you a valid value if the device is registered to the CDMA network:

CellLocation.requestLocationUpdate();
TelephonyManager tm = (TelephonyManager) context.getSystemService(Context.TELEPHONY_SERVICE);
location = (CdmaCellLocation) tm.getCellLocation();
cellID = location.getBaseStationId();
....

Documentation for this method: http://developer.android.com/reference/android/telephony/CellLocation.html#requestLocationUpdate()

score 0 · Answer 3 · answered Sep 09 '14 at 02:01

The real reason you aren't receiving valid coordinates is because some cell providers just don't provide that information, or they they provide wrong information.

I've done tons of personal research into this for one of my published apps. And, to try to help point you in the right direction: (the following are generalizations from many different tests, so you might be able to find one device that differs) - GSM cell providers like T-Mobile will always return invalid. - Sprint tends to return good/valid values. - Verizon provides tower information that tends to be many miles off.

ps - Just in case you are interested, my app is LTE Discovery, in Google Play. It will show you all different types of coordinates possible to retrieve from Android API. (But, I'm not linking to it because it might be against some advertising thing for SO.)

Why getBaseStationLatitude() keeps returning the Integer.MAX_VALUE (unknown)?

3 Answers3

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