阅读说明：本技术 一种类Blake雷达侦察距离计算方法 (Method for calculating detection distance of Blake-like radar ) 是由 张萌 邹本振 王朝 旷生玉 李沛 于 2019-08-07 设计创作，主要内容包括：本发明涉及计算机仿真技术领域,公开了一种类Blake雷达侦察距离计算方法。对侦察公式进行变形并取对数,按Blake工作表的形式将因素项及其分贝值进行记录,求得分贝值中正值总和以及负值的绝对值总和,采用较大的总和减去较小的总和得到净分贝值；根据净分贝值求得自由空间距离以及该条件下的大气衰减损耗,根据大气衰减损耗求出距离因子；根据自由空间距离和距离因子的数据,求出第一近似距离；在第一近似距离条件下,确定大气衰减损耗；迭代计算直至满足两次的大气衰减之差小于精度门限,此时的近似距离即为求得的雷达侦察距离。上述方案适用于所有波段,并且相对于忽略大气衰减的简化处理方法,提高了计算精度。(the invention relates to the technical field of computer simulation, and discloses a method for calculating a detection distance of a Blake-like radar. Deforming the reconnaissance formula, taking logarithm, recording the factor items and the decibel values thereof according to the form of a Blake worksheet, obtaining the sum of positive values and the sum of absolute values of negative values in the decibel values, and subtracting the smaller sum from the larger sum to obtain a net decibel value; obtaining the free space distance and the atmospheric attenuation loss under the condition according to the net decibel value, and obtaining a distance factor according to the atmospheric attenuation loss; calculating a first approximate distance according to the free space distance and the data of the distance factor; determining atmospheric attenuation loss under the condition of a first approximate distance; and (4) performing iterative calculation until the difference between the atmospheric attenuation which meets twice is smaller than the precision threshold, wherein the approximate distance at the moment is the obtained radar reconnaissance distance. The scheme is suitable for all bands, and compared with a simplified processing method for neglecting atmospheric attenuation, the calculation accuracy is improved.)

1. A method for calculating the detection distance of a Blake-like radar is characterized by comprising the following steps:

Step S1, formula for scout distanceA modification is made, where f is the radar signal frequency, P_tFor radar transmitted power (W), G_t' gain of radar antenna in direction of reconnaissance device, G_rFor scout equipment receiving antenna gain, λ is radar signal wavelength, P_rminFor investigating the sensitivity of the receiver of the apparatus, L_rincluding the polarization loss L for the sum of all kinds of losses_pFeeder loss L_fAtmospheric attenuation L_t(ii) a To obtain formula (2):wherein C is_RC/(4 pi), c is the speed of light in vacuum, and takes the value of 3 × 10⁸m/s；

Step S2, taking logarithm of two sides of the formula (2) to obtain a formula (3):

Step S3, according to the form of the Blake working table, the formula (2) and the formula (3) are arranged into a radar reconnaissance distance calculation table, decibel values in the formula (3) corresponding to the factor items are obtained according to the factor items in the formula (2), if the decibel values are larger than 0, a 'positive value' column in the Blake working table is filled, and if the decibel values are smaller than 0, an absolute value of the decibel values is filled in a 'negative value' column in the Blake working table;

Step S4 of obtaining the sum a of all the numbers in the "positive value" row and the sum B of all the numbers in the "negative value" row in step 2, respectively;

Step S5, subtracting the smaller one from the larger one of the sum A and the sum B to obtain a net decibel value X;

Step S6, obtaining the free space distance R according to the net decibel value in the step S5₀；

Step S7, at R₀Under the condition, the atmospheric attenuation loss L is determined according to the calculation method in the ITU-RP.676-3 recommendation_t(dB)1；

Step S8, according to the atmospheric attenuation loss L_t(dB)1Determining the distance factor delta₁；

Step S9, according to the free space distance R₀and a distance factor delta₁To find a first approximate distance R₁；

step S10, at the first approximate distance R₁Under the condition, the atmospheric attenuation loss L is determined according to the calculation method in the ITU-RP.676-3 recommendation_t(dB)2；

In step S11, xi is the accuracy threshold, if L_t(dB)1-L_t(dB)2If | is less than xi, the calculation is stopped, and the first approximate distance R₁Obtaining the obtained radar reconnaissance distance; otherwise, repeat step S8 according to L_t(dB)1And L_t(dB)2The difference between them finds a new distance factor delta₂(ii) a Repeating step S9 to obtain R₁And delta₂Multiplying to obtain a second approximate distance R₂As a new radar reconnaissance distance; repeating the step S10 to obtain a new atmospheric attenuation loss L_t(dB)3；

and step S12, repeating step S11 until the difference between the atmospheric attenuations corresponding to the two radar detection distances is smaller than xi.

2. The method for calculating the distance of a Blake-like radar reconnaissance as claimed in claim 1, wherein the method for calculating the free space distance in step S6 comprises: when B is present<When A is, R₀＝10^X/20(ii) a When B is present>When A is, R₀＝10^-X/20。

3. The method for calculating the distance of a Blake-like radar reconnaissance as claimed in claim 1, wherein the distance factor is obtained in step S8 by:

4. Such as rightThe method for calculating the detection distance of the Blake-like radar according to claim 1, wherein the first approximate distance R is obtained in step S9₁The method comprises the following steps: r₁＝R₀×δ₁。

5. The method of calculating a Blake-like radar reconnaissance distance as claimed in claim 1, wherein the accuracy threshold ξ in step S11 is selected based on the actual requirements of the engineering scene.

Technical Field

The invention relates to the technical field of computer simulation, in particular to a method for calculating a detection distance of a Blake-like radar.

Background

At present, when the reconnaissance distance of the radar is calculated, a reconnaissance equation is basically adopted, and is shown in a formula (1).

in the formula, P_tfor radar transmitted power (W), G_t' gain (multiple) of radar antenna in direction of reconnaissance device, G_rFor scouting equipment receiving antenna gain (multiple), lambda is radar signal wavelength (m), P_nrimFor investigating the receiver sensitivity (W), L of the apparatus_rIs the sum (multiple) of all kinds of losses, including polarization loss L_pFeeder loss L_fAtmospheric attenuation L_tAnd the like. Wherein the atmospheric attenuation L_tThe value of R is determined by the product of the atmospheric attenuation and the reconnaissance distance R (m) per unit distance, and the value of R is dependent on the atmospheric attenuation by the formula (1), so the formula (1) becomes a transcendental equation.

In engineering implementation, atmospheric attenuation is usually directly ignored, the method is fast in calculation, and is feasible when the radar working frequency is less than 1GHz, but the method is not suitable for radars in C bands, particularly over X bands, because the unit distance of radar signals above the bands is large in atmospheric attenuation, the influence on the detection distance is large, and the simplified processing can cause large errors.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: aiming at the existing problems, the invention provides a method for calculating the detection distance of the Blake-like radar, which comprises the following steps:

Step S1, formula for scout distancea modification is made, where f is the radar signal frequency, P_tFor radar transmitted power (W), G_t' gain of radar antenna in direction of reconnaissance device, G_rFor scout equipment receiving antenna gain, λ is radar signal wavelength, P_{r min}For investigating the sensitivity of the receiver of the apparatus, L_rInto various classes

Sum of losses, including polarization loss L_pFeeder loss L_fAtmospheric attenuation L_t(ii) a To obtain formula (2):

Wherein, C_RC/(4 pi), c is the speed of light in vacuum, and takes the value of 3 × 10⁸m/s；

step S2, taking logarithm of two sides of the formula (2) to obtain a formula (3):

Step S3, according to the form of the Blake working table, the formula (2) and the formula (3) are arranged into a radar reconnaissance distance calculation table, decibel values in the formula (3) corresponding to the factor items are obtained according to the factor items in the formula (2), if the decibel values are larger than 0, a 'positive value' column in the Blake working table is filled, and if the decibel values are smaller than 0, an absolute value of the decibel values is filled in a 'negative value' column in the Blake working table;

step S4 of obtaining the sum a of all the numbers in the "positive value" row and the sum B of all the numbers in the "negative value" row in step 2, respectively;

Step S5, subtracting the smaller one from the larger one of the sum A and the sum B to obtain a net decibel value X;

Step S6, obtaining the free space distance R according to the net decibel value in the step S5₀；

Step S7, at R₀Under the condition, the atmospheric attenuation loss L is determined according to the calculation method in the ITU-RP.676-3 recommendation_t(dB)1；

Step S8, according to the atmospheric attenuation loss L_t(dB)1Determining the distance factor delta₁；

Step S9, according to the free space distance R₀And a distance factor delta₁To find a first approximate distance R₁；

step S10, at the first approximate distance R₁Under the condition, the atmospheric attenuation loss L is determined according to the calculation method in the ITU-RP.676-3 recommendation_t(dB)2；

In step S11, xi is the accuracy threshold, if L_t(dB)1-L_t(dB)2If | is less than xi, the calculation is stopped, and the first approximate distance R₁Obtaining the obtained radar reconnaissance distance; otherwise, repeat step S8 according to L_t(dB)1And L_t(dB)2The difference between them finds a new distance factor delta₂(ii) a Repeating step S9 to obtain R₁and delta₂multiplying to obtain a second approximate distance R₂As a new radar reconnaissance distance; repeating the step S10 to obtain a new atmospheric attenuation loss L_t(dB)3；

and step S12, repeating step S11 until the difference between the atmospheric attenuations corresponding to the two radar detection distances is smaller than xi.

Further, the method of determining the free space distance in step S6 includes: when B is present<when A is, R₀＝10^X/20(ii) a When B is present>When A is, R₀＝10^-X/20。

Further, the method of determining the distance factor in step S8 includes:

further, in the step S9, the first approximate distance R is obtained₁The method comprises the following steps: r₁＝R₀×δ₁。

Further, the precision threshold ξ in the step S11 is selected according to the actual requirements of the engineering scene.

Compared with the prior art, the beneficial effects of adopting the technical scheme are as follows: by adopting the technical scheme of the invention, on the basis of a Blake working table (a table for quickly calculating the detection distance of the radar), a radar reconnaissance distance calculation method suitable for a full-wave band is provided; compared with a simplified processing method for neglecting atmospheric attenuation, the method improves the calculation precision, and can solve the problem of solving the transcendental equation in engineering calculation under the condition of meeting a certain precision. In addition, the method is applicable to all bands.

Detailed Description

The invention is further described below with reference to examples:

Transforming equation (1) to obtain:

Wherein f is a radar signal frequency (Hz).

Taking logarithm of two sides of formula (2) to obtain

And (3) arranging the formula (2) and the formula (3) into a radar reconnaissance distance calculation table according to the form of a Blake working table, and arranging and filling reconnaissance equipment and radar parameters into a table, which is shown in a table 1.

TABLE 1 Radar reconnaissance distance calculation example Table

Calculating decibel values in the formula (3) corresponding to the factor items according to the factor items in the formula (2), filling a positive value if the decibel value is greater than 0, and filling a negative value (absolute value) if the decibel value is less than 0;

Obtaining a "positive value" column sum and a "negative value (absolute value)" column sum, wherein "positive value" a equals 318.39 and "negative value (absolute value)" B equals 206.52;

Placing the small sum B-206.52 below the large sum a-318.39, the large sum decreasing to give a net decibel value X, i.e., X-a-B-318.39-206.52-111.87;

Calculating to obtain R according to the net decibel value X₀＝10^X/20＝392193≈392km；

According to the ITU-RP.676-3 recommendation, the atmospheric pressure is 1013.25hPa, the temperature is 15 ℃, and the water vapor density is 7.5g/m³The atmospheric attenuation per kilometer is 0.0267 dB. Corresponds to R₀Determining atmospheric attenuation lossesL_t(dB)1＝0.0267*392＝10.4664；

Finding out a distance factor according to the atmospheric attenuation loss,

r is to be₀and delta₁Multiplying to obtain a first approximate distance R₁≈117km；

At R₁Corresponding to the atmospheric attenuation loss L under the condition_t(dB)2＝3.14；

Selecting a precision threshold xi to be 0.5dB according to engineering requirements, obtaining a reconnaissance distance meeting the precision through 8 steps of iteration to be about 199km, and obtaining specific results shown in a table 2:

TABLE 2 calculation results table

n	Rn-1/km	Lt(dB)n	Lt(dB)(n-1)-Lt(dB)n
				1	392	10.466	-10.466
2	117	3.14	7.326
				3	273	7.294	-4.154
4	169	4.518	2.776
				5	232	6.211	-1.693
6	190	5.097	1.114
				7	215	5.767	-0.67
8	199	5.314	0.453

The invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification and any novel method or process steps or any novel combination of features disclosed. Those skilled in the art to which the invention pertains will appreciate that insubstantial changes or modifications can be made without departing from the spirit of the invention as defined by the appended claims.