要实现Android定期获取位置，即使应用实例已终止，可以使用后台服务和定时器来实现。下面是一个示例代码：

1. 创建一个服务类（LocationService.java）来获取位置：

import android.Manifest;
import android.app.Service;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.location.Location;
import android.os.Bundle;
import android.os.IBinder;
import android.util.Log;

import androidx.annotation.NonNull;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import com.google.android.gms.location.FusedLocationProviderClient;
import com.google.android.gms.location.LocationCallback;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationResult;
import com.google.android.gms.location.LocationServices;

public class LocationService extends Service {

    private static final String TAG = "LocationService";
    private static final long INTERVAL = 10 * 1000; // 10秒
    private static final long FASTEST_INTERVAL = 5 * 1000; // 5秒

    private FusedLocationProviderClient fusedLocationClient;
    private LocationCallback locationCallback;

    @Override
    public void onCreate() {
        super.onCreate();
        fusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
        createLocationRequest();
        startLocationUpdates();
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        return START_STICKY; // 在服务被杀死后自动重启
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        stopLocationUpdates();
    }

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    private void createLocationRequest() {
        LocationRequest locationRequest = new LocationRequest();
        locationRequest.setInterval(INTERVAL);
        locationRequest.setFastestInterval(FASTEST_INTERVAL);
        locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);

        locationCallback = new LocationCallback() {
            @Override
            public void onLocationResult(LocationResult locationResult) {
                if (locationResult == null) {
                    return;
                }
                for (Location location : locationResult.getLocations()) {
                    Log.d(TAG, "onLocationResult: " + location.getLatitude() + ", " + location.getLongitude());
                    // 在此处处理获取到的位置信息
                }
            }
        };

        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
            fusedLocationClient.requestLocationUpdates(locationRequest, locationCallback, null);
        }
    }

    private void startLocationUpdates() {
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
            fusedLocationClient.requestLocationUpdates(locationRequest, locationCallback, null);
        }
    }

    private void stopLocationUpdates() {
        fusedLocationClient.removeLocationUpdates(locationCallback);
    }
}

2. 在AndroidManifest.xml文件中声明服务：

3. 在需要启动服务的地方，例如MainActivity中的onCreate()方法中，启动服务：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    Intent serviceIntent = new Intent(this, LocationService.class);
    startService(serviceIntent);
}

这样，即使应用实例已终止，服务仍然可以在后台定期获取位置信息。请确保在AndroidManifest.xml文件中申请了获取位置的权限（ACCESS_FINE_LOCATION或ACCESS_COARSE_LOCATION）。