CN103743403A - Calculating method of single-frequency signal reverberation center - Google Patents

Abstract

The invention discloses a calculating method of a single-frequency signal reverberation center. The method comprises the processing processes: (a), calculating the frequency of a reverberation center by adopting a gravity center method according to a frequency response result; (b), smoothening the frequency of the reverberation center of the current frame by adopting a time smoothening technology according to the calculation result of the frequency of the reverberation center of the former frame, wherein the smoothened frequency is used as a final calculation result. The calculating method has the beneficial effects that the calculation of the single-frequency signal reverberation center of a homing system is completed, the single-frequency signal reverberation center can be estimated accurately by adopting the method, and the navigation speed deviation, the movement posture change and the ocean current influence can be adapted, so that the false alarm probability is reduced and the detection performance of single-frequency signals is improved; by the adoption of the gravity center method and the time smoothening technology, according to the method, the convenience in calculation is achieved, and the requirement on the detection on the single-frequency signals of an XX homing system can be met.

Description

The computing method at a kind of simple signal reverberation center

Technical field

The computing method that the present invention relates to a kind of simple signal reverberation center, belong to self-conductance field of engineering technology, be mainly used in calculating simple signal reverberation center and improve detection performance under real boat condition.

Background technology

In homing system, simple signal is one of topmost signal form.In single-frequency signal detection process, reverberation is the key factor that impact detects performance.At present, the interval that homing system mainly arranges certain Doppler spread is based on experience value reverberation district, under real boat state, due to the deviation of the speed of a ship or plane and setting speed and the impact of ocean current and state of motion, there is fluctuation in reverberation center, thereby has increased the false-alarm probability of system and reduced detection performance.There is no at present the reverberation center calculation method based on gravity model appoach.

Summary of the invention

The object of the invention is: propose first a kind of reverberation center calculation method based on gravity model appoach, this scheme have calculate easy, result is accurate, adaptable advantage, and by reality navigate checking can accurately estimate reverberation center, there is very high practical value and application prospect.

Technical scheme of the present invention is: the computing method at a kind of simple signal reverberation center, and main methods is: a. adopts gravity model appoach to calculate reverberation centre frequency according to frequency response results; B. utilize the reverberation centre frequency result of calculation of previous frame, adopt time smoothing technology to carry out smoothly the reverberation centre frequency of present frame, and as final calculation result.

The method specifically comprises the steps:

Step 1: gravity model appoach is determined reverberation centre frequency

According to the frequency response P (k, i) of i frame data, utilize gravity model appoach to calculate the centre frequency of reverberation, k=0 wherein ..., N-1.I frame reverberation centre frequency Φ (i) computing formula is:

$\mathrm{\Φ}\left(i\right)=\frac{\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}P(k,i)*k}{\underset{k=0}{\overset{N-1}{\mathrm{\Σ}}}P(k,i)}......\left(1\right)$

Step 2: reverberation centre frequency is carried out to time smoothing

Since L frame, reverberation center is carried out smoothly, can improving like this stability of reverberation center calculation, specific formula for calculation is:

$F\left(i\right)=\frac{w\×\mathrm{\Φ}\left(i\right)+\underset{k=i-L+1}{\overset{i-1}{\mathrm{\Σ}}}F\left(k\right)}{L-1+w},i\≥L......\left(2\right)$

In formula, the weight that w is i frame, should meet 0<w<1.By regulating weight can reduce the impact of target echo on reverberation center calculation.F (i) is the final calculation result of i frame reverberation centre frequency.

The computing method at the simple signal reverberation center that the present invention proposes have following significant advantage and the innovation that is different from traditional reverberation district method:

Feature 1: proposed first the simple signal reverberation center calculation method based on gravity model appoach

According to the frequency response of reverberation, adopt gravity model appoach to calculate reverberation center, the reverberation center of causing for thunder speed deviation, state of motion and ocean current fluctuation has certain adaptability;

Feature 2: adopt time smoothing technology to improve stability and the accuracy of reverberation center calculation

In real boat, in the single work period of homing system, do not carry out motor-driven, therefore in the single work period of homing system, in the short time, reverberation center is basicly stable, adopt time smoothing technology can improve stability and the accuracy of reverberation center calculation, and can reduce echoed signal to calculating the impact at reverberation center.

The present invention relates to the computing method at a kind of simple signal reverberation center, the method is on simple signal frequency domain detection basis, adopt gravity model appoach and time smoothing technique computes reverberation center, and there is certain adaptability for thunder speed deviation, state of motion variation and ocean current in real boat, not only can accurately estimate reverberation center, and there is higher stability.The method, can practical requirement through repeatedly real boat checking.

The invention has the beneficial effects as follows: the present invention proposes a kind of computing method of the simple signal reverberation center based on gravity model appoach and time smoothing technology:

1) the present invention has completed the calculating at homing system simple signal reverberation center, adopt the method can accurately estimate single-frequency signal reverberation center, and can adapt to that speed of a ship or plane deviation, state of motion change and ocean current impact, thereby reduce false-alarm probability and improve the detection performance of simple signal;

2) the present invention adopts gravity model appoach and time smoothing technology, and the method is calculated easy, can meet the needs of homing system single-frequency signal detection.

Accompanying drawing explanation

Fig. 1: the processing flow chart of the computing method at a kind of simple signal reverberation center

Embodiment

Now in conjunction with the embodiments, the invention will be further described for accompanying drawing:

The computing method at the simple signal reverberation center in the present embodiment comprise the steps:

Step 1: gravity model appoach is determined reverberation centre frequency

According to the frequency response P (k, i) of i frame data, utilize gravity model appoach to calculate the centre frequency of reverberation, k=0 wherein ..., N-1.I frame reverberation centre frequency Φ (i) computing formula is:

$\mathrm{\&Phi;}\left(i\right)=\frac{\underset{k=0}{\overset{N-1}{\mathrm{\&Sigma;}}}P(k,i)*k}{\underset{k=0}{\overset{N-1}{\mathrm{\&Sigma;}}}P(k,i)}......\left(1\right)$

In the present embodiment, N=20, the value of each frame rate response P is as shown in table 1, according to above formula, can be calculated the value of reverberation centre frequency Φ (i) as shown in table 2.

The value of table 1 frequency response P

The 1st frame	The 2nd frame	The 3rd frame	The 4th frame	The 5th frame	The 6th frame	The 7th frame	The 8th frame	The 9th frame	The 10th frame
										4	4	5	23	15	7	8	2	17	2
9	1	13	6	17	12	14	20	12	0
										17	10	11	2	20	3	4	0	23	3
6	1	10	9	26	13	5	3	15	35
										21	3	19	0	9	6	15	10	1	2
5	5	13	12	2	4	17	16	4	16
										16	8	1	3	10	6	2	1	7	19
3	0	4	12	12	1	4	5	8	6
										5	19	4	10	5	11	8	10	7	7
3	4	11	7	15	1	4	8	5	26
										4	6	31	13	17	11	7	3	8	5
4	10	6	3	5	9	7	12	4	2
										4	6	3	9	1	2	15	0	8	8
6	8	2	3	20	2	5	5	5	11
										6	5	4	5	8	9	1	1	5	18
8	9	15	5	5	1	8	3	6	5
										19	2	8	6	19	12	7	2	7	11
3	2	11	12	4	3	12	11	7	6
										2	6	5	6	4	3	9	4	11	4
7	1	13	0	12	23	13	7	7	17

Table 2 reverberation centre frequency Φ (i) result of calculation

The 1st frame	The 2nd frame	The 3rd frame	The 4th frame	The 5th frame	The 6th frame	The 7th frame	The 8th frame	The 9th frame	The 10th frame
										9.5	10.4636	10.2169	9.2534	9.2124	10.8921	10.5333	9.5528	8.982	10.6355

Step 2: reverberation centre frequency is carried out to time smoothing

Since L frame, reverberation center is carried out smoothly, can improving like this stability of reverberation center calculation, specific formula for calculation is:

$F\left(i\right)=\frac{w\&times;\mathrm{\&Phi;}\left(i\right)+\underset{k=i-L+1}{\overset{i-1}{\mathrm{\&Sigma;}}}F\left(k\right)}{L-1+w},i\&GreaterEqual;L......\left(2\right)$

In formula, the weight that w is i frame, should meet 0<w<1.By regulating weight can reduce the impact of target echo on reverberation center calculation.F (i) is the final calculation result of i frame reverberation centre frequency.

In the present embodiment, L=5, w=0.9.Finally calculate to such an extent that F (i) is worth as shown in table 3.

The final calculation result of table 3 reverberation centre frequency

The 1st frame	The 2nd frame	The 3rd frame	The 4th frame	The 5th frame	The 6th frame	The 7th frame	The 8th frame	The 9th frame	The 10th frame
										9.5000	10.4636	10.2169	9.2534	9.7398	10.0973	9.9566	9.7234	9.7145	10.0130

Claims (1)

1. the computing method at simple signal reverberation center, is characterized in that, comprise the steps:

Step 1: gravity model appoach is determined reverberation centre frequency

According to the frequency response P (k, i) of i frame data, utilize gravity model appoach to calculate the centre frequency of reverberation, k=0 wherein ..., N-1.I frame reverberation centre frequency Φ (i) computing formula is:

$\mathrm{\&Phi;}\left(i\right)=\frac{\underset{k=0}{\overset{N-1}{\mathrm{\&Sigma;}}}P(k,i)*k}{\underset{k=0}{\overset{N-1}{\mathrm{\&Sigma;}}}P(k,i)}......\left(1\right)$

Step 2: reverberation centre frequency is carried out to time smoothing

Since L frame, reverberation center is carried out smoothly, specific formula for calculation is:

$F\left(i\right)=\frac{w\&times;\mathrm{\&Phi;}\left(i\right)+\underset{k=i-L+1}{\overset{i-1}{\mathrm{\&Sigma;}}}F\left(k\right)}{L-1+w},i\&GreaterEqual;L......\left(2\right)$

In formula, the weight that w is i frame, should meet 0<w<1.F (i) is the final calculation result of i frame reverberation centre frequency.

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