A Fast Direct Position Determination Algorithm for LFM Signal Based on Spectrum Detection

Algorithm 1

Summary of the FDPD Algorithm.

Input: The observed signal r, the base station coordinates, space of grid search () for p;

Output: Estimated parameters and the position of the radiation source;

1: For l =1 ··· L do

2:   Compute the SP for th observed signal.

3:   Compute the maximum SP of the th observed signal

4:   Compare the maximum SP difference between the LFM

5:   Signals and noise signal with the threshold value.

6: End for

7: If the maximum SP difference > threshold then

8:   Compute the emitter position p using Equation (19)–(22).

9: End if

10: If the maximum SP difference < threshold then

11:   For l =1 ··· L do

12:    Compute the emitter position initial ^p₁ using

13:    Equation (19) - (22).

14:    Determine the search range () by the

15:    Error analysis of Chan and Taylor algorithm.

16:    For do

17:     Estimate the IF of the th observed signal using Equation (16).

18:     Estimate the initial frequency and chirp rate.

19:     Extract the IF and compute the fitting error every time

20:     Window per unit time at different position.

21:     Compute the objective function value using Equation (24).

22:     Find the maximum of the objective function and compute the

23:     Emitter position p.

24:    End for

25:   End for

26: End if