public int onStartCommand(Intent intent, int flags, int startId)
{
    startService(intent);

    _bootCompletedReciever = new BroadcastReceiver()
    {
        @Override
        public void onReceive(Context context, Intent intent)
        {
            Log.d(TAG, "Got boot completed");
        }
    };


    IntentFilter filter = new IntentFilter("android.intent.action.BOOT_COMPLETED");
    registerReceiver(_bootCompletedReciever, filter);

    return START_NOT_STICKY;
}

<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

public class BootBroadcastReceiver extends BroadcastReceiver
{
    @Override
    public void onReceive(Context context, Intent intent)
    {
        Intent service = new Intent(context, S_GPS.class);
        context.startService(service);
    }
}

<receiver android:name=".BroadcastReceivers.BootBroadcastReceiver" android:enabled="true" android:exported="false">
    <intent-filter>
        <action android:name="android.intent.action.BOOT_COMPLETED"/>
    </intent-filter>
</receiver>

android:enabled=["true" | "false"]

context.getPackageManager()
    .setComponentEnabledSetting(ComponentName componentName, int newState, int flags);

componentName   The component to enable
newState        The new enabled state for the component. The legal values for this state are:
        COMPONENT_ENABLED_STATE_ENABLED, COMPONENT_ENABLED_STATE_DISABLED and COMPONENT_ENABLED_STATE_DEFAULT
        The last one removes the setting, thereby restoring the component's state to whatever was set in it's manifest (or enabled, by default).
flags           Optional behavior flags: DONT_KILL_APP or 0.