Research Article

An Efficient Geolocation Method for Malicious LBSD Users Based on Dynamic Adjustment of Probes

Algorithm 1

Dispose of anomalous probes combinations based on coordinate inversion.
Input:, , , ,
Output: execution code.
1 code =0; //Initial value of execution code.
2 ; //List ofto be evaluated.
3 =1; //Times of coordinate inversion.
4 axis = X;
5 ifthen://Judge whether the localization is successful.
6 code =1;
7 break; //End the localization.
8 end.
9 whiledo://Detect anomalous probe combination.
10 if 3 then://All coordinate inversions are tried.
11 code = 2;
12 break; //End inversion process.
13 end.
14 if axis == X then://Invert coordinates of x-axis generated probe.
15 = (, 0);
16 = LS(, ); //Estimate target location based on new probes.
17 update ; //Obtain target distance at the evaluation location.
18 .append(());
19 = ;
20 axis = Y;
21 continue; //Verification.
22 end.
23 else.
24 if axis == Y then://Invert coordinates of the probe on the y-axis.
25 = (, 0);
26 = (0,);
27 = LS(, ); //Estimate target location based on new probes.
28 update ; //Obtain target distance at the evaluation location.
29 .append(());
30 = ;
31 axis = XY.
32 continue; //Verification.
33 end.
34 else.
35 = (, 0); //Invert coordinates of 2 generated probes.
36 = (0,);
37 = LS(, ); //Estimate location based on new probes.
38 update ; //Obtain target distance at the evaluation location.
39 .append(());
40 = ;
41 continue; //Verification.
42 end.
43 end
44 return:, code.