A troposphere scattering based radar over-the-horizon reconnaissance positioning probability calculation method

Abstract

The application discloses a radar over-the-horizon reconnaissance positioning probability calculation method based on a troposphere scattering, and belongs to the field of computer simulation, and comprises the following steps: calculating an over-the-horizon reconnaissance probability of a radar by a single reconnaissance station through a dichotomy method; and multiplying a plurality of the reconnaissance probabilities to obtain an over-the-horizon reconnaissance positioning probability of the radar by a plurality of reconnaissance stations. The application can assist a user in further developing a situation analysis and providing support for applications such as station layout selection.

Description

Technical Field

[0001] The present invention relates to the field of computer simulation, and more specifically to a method for calculating the probability of radar over-the-horizon reconnaissance positioning based on tropospheric scattering. Background Art

[0002] During beyond-horizon radar reconnaissance, the likelihood of radar detection at different locations follows a certain statistical probability due to the uncertainty of tropospheric scatter (not considering the impact of intercept probability caused by antenna scanning and frequency domain scanning on both the transmitter and receiver sides). Currently, beyond-horizon radar reconnaissance positioning analysis typically only calculates positioning accuracy, without considering positioning probability, making it difficult for users to fully analyze and assess the situation. Summary of the Invention

[0003] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a method for calculating the probability of radar over-the-horizon reconnaissance positioning based on tropospheric scattering, which can assist users in further conducting situation analysis and provide support for applications such as station site selection.

[0004] The object of the present invention is achieved through the following solutions:

[0005] A method for calculating the probability of radar over-the-horizon reconnaissance positioning based on tropospheric scattering comprises the following steps:

[0006] S1, calculate the probability of over-the-horizon reconnaissance of a single reconnaissance station to the radar by bisection method;

[0007] S2, multiplying the plurality of reconnaissance probabilities to obtain the over-the-horizon reconnaissance positioning probability of the radar by the multiple reconnaissance stations.

[0008] Furthermore, in step S1, the sub-steps are included:

[0009] The signal power reaching the receiver of the reconnaissance equipment after tropospheric scattering is expressed as P r :

[0010] P r =P t +G t +G r -L (1)

[0011] Where, P t is the radar transmission power, G t is the radar transmitting antenna gain, G r is the receiving antenna gain of the reconnaissance equipment, L includes the troposcatter transmission loss Ls and the sum of the receiving and transmitting system losses L Sys , polarization loss L Polar When P r Greater than the receiver sensitivity P SenIf the condition of over-the-horizon reconnaissance is met, otherwise, the condition is not met;

[0012] The median of tropospheric scatter transmission loss under the probability q is:

[0013] L S (q)=F+30lgf+10lgd+30lgθ+L N +L c -Y(q) (2)

[0014] In the formula, F is a meteorological factor, f is a signal frequency, d is a path length, θ is a scattering angle, L N is a transmission loss term related to the height of a common scatterer, L c is an antenna medium coupling loss, and Y(q) is a fading depth with a propagation reliability of q;

[0015] According to the formulas (1) and (2), the over-the-horizon reconnaissance probability of a radar at a distance reconnaissance device d is q when the condition of formula (3) is met:

[0016]

[0017] The q value is calculated by bisection method.

[0018] Further, the q value is calculated by bisection method, including the following sub-steps:

[0019] Firstly, it is judged whether the path length d is within the range of tropospheric scatter propagation, if not, the calculation condition is not met; if yes, the following conditions one and two are calculated:

[0020] Condition one: L S (0) is calculated according to formula (2) when q=0, it is judged whether L max -L s (0)<0 is established; if yes, the calculation condition is not met, and the calculation is ended;

[0021] Condition two: L S (100) is calculated according to formula (2) when q=100, it is judged whether L max -L s (100)>0 is established; if yes, the probability is 100%, and the calculation is ended;

[0022] When the conditions one and two are not met, the q value is searched in (0, 100) by bisection method, until the condition in formula (5) is met, then q=(q max +q min ) / 2 is taken; wherein is a set error threshold;

[0023]

[0024] Furthermore, in step S2, the sub-steps are included:

[0025] S21, calculate the beyond-horizon reconnaissance probability q1, q2, q3, ...q of each reconnaissance station to the radar according to the calculation method in step S1. n ;

[0026] S22, when multiple reconnaissance stations locate radar beyond visual range, each reconnaissance station is required to intercept the radar signal, then the positioning probability is the product of multiple reconnaissance probabilities

[0027] Furthermore, Ls changes dynamically, and Ls is a probability statistical value of a semi-empirical formula obtained based on local test data.

[0028] Furthermore, F, θ, L N , L c , and Y(q) are calculated using the existing scheme.

[0029] Furthermore, L S (q) Theoretically, it is related to the following parameters: probability, radio-climatic zone of propagation, height of transmitter and receiver above the ground, path length, signal frequency, and antenna gain of transmitter and receiver.

[0030] Furthermore, the upper limit of the tropospheric scatter propagation range is related to the highest altitude of the scatterer, and the lower limit of the tropospheric scatter propagation range is the line of sight between the transmitter and the receiver.

[0031] Furthermore, the upper limit of the tropospheric scatter propagation range is between 1100 and 1200 km.

[0032] Furthermore, the lower limit of the tropospheric scatter propagation range is the line of sight between the transmitter and receiver, and the calculation method is formula (4);

[0033]

[0034] Where h t and h r are the altitudes of the radar and reconnaissance stations respectively.

[0035] The beneficial effects of the present invention include:

[0036] This technical solution proposes a method for calculating the probability of over-the-horizon radar reconnaissance positioning based on tropospheric scatter. This method calculates the probability of over-the-horizon reconnaissance from different reconnaissance stations for a radar at a specific location in space, thereby obtaining the positioning probability. This method adds one-dimensional reference information to traditional positioning accuracy, assisting users in conducting more comprehensive situation analysis and station site selection. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only show some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort.

[0038] Figure 1 Method step flow chart of the embodiments of the present application. DETAILED DESCRIPTION

[0039] All features disclosed in the embodiments of the present application, or all steps in the methods or processes impliedly disclosed, can be combined and / or extended, replaced, in any manner, except for the features and / or steps that are mutually exclusive.

[0040] The technical solutions of the present application first calculate the over-the-horizon reconnaissance probability of a single reconnaissance station to a radar by dichotomy, and then calculate the over-the-horizon reconnaissance positioning probability to the radar by integrating multiple reconnaissance probabilities. The specific steps include the following:

[0041] a) Calculate the over-the-horizon reconnaissance probability of a single reconnaissance station to a radar

[0042] The signal power (dBW) arriving at the receiver of the reconnaissance equipment after the tropospheric scattering can be expressed as:

[0043] P r = P t + G t + G r - L (1)

[0044] In the formula, P t is the radar transmitting power (dBW), G t is the radar transmitting antenna gain (dB), G r is the receiving antenna gain of the reconnaissance equipment (dB), and L mainly includes the sum of the tropospheric scattering transmission loss Ls (dB) and the receiving and transmitting system loss L Sys (dB), and the polarization loss L Polar (dB). When P r is greater than the receiver sensitivity P Sen (dBW), the over-the-horizon reconnaissance condition is met.

[0045] Affected by geographical, time and other factors, Ls dynamically changes and is difficult to accurately calculate. It is a probability statistical value of a semi-empirical formula obtained according to a large amount of test data in the local area. The median value of the tropospheric scattering transmission loss under the probability q (i.e. the dynamic value of Ls does not exceed L S (q) with the probability of q, unit: dB) is:

[0046] L S (q) = F + 30 lg f + 10 lg d + 30 lg 0 + L N + L c -Y(q) (2)

[0047] Where, F - meteorological factor (dB);

[0048] f - signal frequency (MHz);

[0049] d - path length (km);

[0050] 0 - scattering angle (milli-radian (mrad));

[0051] L N - transmission loss term related to the height of common scatterers (dB);

[0052] L c - antenna medium coupling loss (dB);

[0053] Y(q) - fading depth with propagation reliability q (dB).

[0054] Except for f and d, the calculation method of the other 5 variables is described in the published literature (such as: the monograph “Radio Wave Propagation Engineering Calculation” published by Xi'an University of Electronic Science and Technology Press in 1989 (Author: Xiao Jingming, etc.), the paper “Radio Space Attenuation Analysis” published in “Space Electronic Countermeasure” in 2019 No. 4 26-29 (Author: Niu Shiwei, etc.)). In summary, L S (q) is theoretically related to the following parameters: probability, propagation belongs to radio climate area, height of the transmitter and receiver, path length, signal frequency, antenna gain of the transmitter and receiver.

[0055] According to formulas (1) and (2), the over-the-horizon reconnaissance probability of the radar at the distance reconnaissance equipment d is the q value when formula (3) is satisfied:

[0056] L s (q) = L max

[0057] Where, L max = P t + G t + G r -P Sen -L Sys -L Polar (3)

[0058] The q value that satisfies this condition cannot be directly calculated by mathematical equations, and is approximated by the bisection method here, and the calculation steps are as follows:

[0059] 1) First, determine whether the path length d is within the tropospheric scatter propagation range. If not, the calculation conditions are not met. The lower limit of the tropospheric scatter propagation range is the line-of-sight distance (km) between the transmitter and receiver, calculated as shown in formula (4). The upper limit of the tropospheric scatter propagation range is related to the maximum altitude of the scatterer and is generally 1100 to 1200 km.

[0060]

[0061] Among them, h t and h r are the altitudes of the radar and reconnaissance stations respectively (m).

[0062] 2) Calculate L when q = 0 according to formula (2) S (0), judge L max -L s (0) < 0. If true, the calculation condition is not met and the calculation ends.

[0063] 3) Calculate L when q = 100 according to formula (2) S (100), determine L max -L s Is (100)>0 true? If true, the probability is 100% and the calculation ends.

[0064] 4) When conditions 2) and 3) are not met, use the binary search method to find the value of q in the range (0, 100) until the condition in formula (5) is met, then take q = (q max +q min ) / 2. is the set error threshold.

[0065]

[0066] b) Calculate the probability of multiple stations positioning the radar

[0067] The calculation steps are as follows:

[0068] 1) Calculate the BVR reconnaissance probability q1, q2, q3, ...q of each station to the radar according to the calculation method in a). n ;

[0069] 2) When multiple stations locate the radar beyond the horizon, each station is required to intercept the radar signal. The positioning probability is the product of multiple reconnaissance probabilities.

[0070] In this example, the parameters of two over-the-horizon reconnaissance equipment are shown in Table 1, and the parameters of one radar are shown in Table 2. Assuming that the transmission and reception are co-polarized, that is, L Polar =0; the radio climate zone to which propagation belongs is selected as the oceanic temperate sea surface; Set to 1 (i.e. the error of the reconnaissance probability calculation result is less than 1%); the upper limit of the tropospheric scatter propagation range is 1105km.

[0071] Table 1 Parameters of reconnaissance equipment

[0072] Serial number Parameter items unit Reconnaissance Equipment A Reconnaissance Equipment B 1 Upper limit of operating frequency GHz 8 10 2 Operating frequency lower limit GHz 0.5 0.4 3 Station height m 100 30 4 Receiving antenna gain dB 40 35 5 Receiver sensitivity dBW -95 -100 6 Receiving loss dB 3 3

[0073] Table 2 Parameters of radar objects

[0074] Serial number Parameter items unit Numerical 1 Operating frequency GHz 1 2 Radar altitude m 30 3 Transmitter power kW 300 4 Transmitting antenna gain dB 35 5 Transmission loss dB 0 6 Path distance to device A km 550 7 Path distance to device B km 600

[0075] For reconnaissance device A:

[0076] 1)L max =54.77+35+40+95-3=221.77dB;

[0077] 2)D LOS =63.77km, then the radar is within the beyond-horizon detection range;

[0078] 3)L s (0)=175.69, then L max -L s (0)>0;

[0079] 4)L s (100) = 247.83, then L max -L s (100)<0;

[0080] 5) After the dichotomy calculation, the probability of beyond-visual-range reconnaissance of the radar is 0.8.

[0081] For reconnaissance equipment B:

[0082] 1)L max =54.77+35+35+100-3=221.77dB;

[0083] 2)D LOS =45.13km, then the radar is within the beyond-horizon detection range;

[0084] 3)L s (0)=179.77, then L max -L s (0)>0;

[0085] 4)L s (100) = 250.65, then L max -L s (100)<0;

[0086] 5) After the dichotomy calculation, the probability of beyond-visual-range reconnaissance of the radar is 0.68.

[0087] Then, the probability of beyond-horizon positioning of the radar by stations A and B is 0.8*0.68=0.544.

[0088] It should be noted that within the scope of protection defined in the claims of the present invention, the following embodiments can be combined and / or expanded or replaced in any logical way from the above specific implementation methods, such as disclosed technical principles, disclosed technical features or implicitly disclosed technical features.

[0089] Example 1

[0090] like Figure 1 As shown, a method for calculating the probability of radar over-the-horizon reconnaissance positioning based on tropospheric scattering includes the following steps:

[0091] S1, calculate the probability of over-the-horizon reconnaissance of a single reconnaissance station to the radar by bisection method;

[0092] S2, multiplying the plurality of reconnaissance probabilities to obtain the over-the-horizon reconnaissance positioning probability of the radar by the multiple reconnaissance stations.

[0093] Example 2

[0094] On the basis of Example 1, step S1 includes the following sub-steps:

[0095] The signal power reaching the receiver of the reconnaissance equipment after tropospheric scattering is expressed as P r :

[0096] P r =P t +G t +G r -L (1)

[0097] Where, P t is the radar transmission power, G t is the radar transmitting antenna gain, G r is the receiving antenna gain of the reconnaissance equipment, L includes the troposcatter transmission loss Ls and the sum of the receiving and transmitting system losses L Sys , polarization loss L Polar When P r Greater than the receiver sensitivity P Sen If the condition of beyond visual range detection is met, it is not met otherwise.

[0098] The median troposcatter transmission loss under probability q is:

[0099] L S (q) = F + 30lgf + 10lgd + 30lgθ + LN +L c -Y(q) (2)

[0100] Where F is the meteorological factor, f is the signal frequency, d is the path length, θ is the scattering angle, and L is the N is the transmission loss term related to the height of the common scatterer, L c is the antenna dielectric coupling loss, Y(q) is the fading depth with propagation reliability q;

[0101] According to formulas (1) and (2), the probability of over-the-horizon reconnaissance of the radar at a distance d from the reconnaissance equipment is the q value when the condition of formula (3) is satisfied:

[0102]

[0103] The q value is approximated by bisection method.

[0104] Example 3

[0105] Based on Example 2, the approximate calculation of the q value by bisection method includes the following sub-steps:

[0106] First, determine whether the path length d is within the tropospheric scatter propagation range. If not, the calculation conditions are not met. If so, calculate the following conditions 1 and 2:

[0107] Condition 1: Calculate L when q = 0 according to formula (2) S (0), judge L max -L s (0)<0 is true; if true, the calculation condition is not met and the calculation ends;

[0108] Condition 2: Calculate L when q = 100 according to formula (2) S (100), judge L max -L s (100)>0 is true; if true, the probability is 100% and the calculation ends;

[0109] When conditions 1 and 2 are not met, the value of q is searched cyclically between (0, 100) by binary search until the condition in formula (5) is met, then q=(q max +q min ) / 2; where is the set error threshold;

[0110]

[0111] Example 4

[0112] On the basis of Example 2 or 3, in step S2, the sub-steps are included:

[0113] S21, calculate the beyond-horizon reconnaissance probability q1, q2, q3, ...q of each reconnaissance station to the radar according to the calculation method in step S1. n ;

[0114] S22, when multiple reconnaissance stations locate radar beyond visual range, each reconnaissance station is required to intercept the radar signal, then the positioning probability is the product of multiple reconnaissance probabilities

[0115] The units involved in the embodiments of the present invention may be implemented in software or hardware, and the units described may also be provided in a processor. In some cases, the names of these units do not limit the units themselves.

[0116] According to one aspect of an embodiment of the present invention, a computer program product or computer program is provided, comprising computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the methods provided in the various optional implementations described above.

[0117] As another aspect, embodiments of the present invention further provide a computer-readable medium, which may be included in the electronic device described in the above embodiments, or may exist independently and not incorporated into the electronic device. The computer-readable medium carries one or more programs, and when executed by the electronic device, the electronic device implements the methods described in the above embodiments.

[0118] The parts not involved in the present invention are the same as the existing technology or can be implemented by using the existing technology.

[0119] The above technical solution is only one embodiment of the present invention. For those skilled in the art, it is easy to make various types of improvements or modifications based on the application methods and principles disclosed in the present invention, and it is not limited to the method described in the above specific embodiment of the present invention. Therefore, the method described above is only preferred and does not have a restrictive meaning.

[0120] In addition to the above examples, those skilled in the art may obtain other embodiments based on the above disclosure or by utilizing knowledge or technology in related fields to make modifications. The features of each embodiment may be interchangeable or replaced. The modifications and changes made by those skilled in the art do not depart from the spirit and scope of the present invention and should be within the scope of protection of the claims attached to the present invention.

Claims

1. A method for calculating the probability of radar over-the-horizon reconnaissance positioning based on tropospheric scatter, characterized in that: The following steps are involved: S1, calculating the probability of a single reconnaissance station detecting a radar beyond the visual range by a dichotomy method; in step S1, the sub-steps are as follows: The signal power reaching the receiver of the reconnaissance equipment after passing through the troposphere is expressed as : (1) Where, is the radar transmission power, is the radar transmitting antenna gain, is the receiving antenna gain of the reconnaissance equipment, L Including troposcatter transmission loss Ls The sum of the losses of the receiving and transmitting systems L Sys , polarization loss L Polar ;when Greater than receiver sensitivity P Sen If the condition of beyond visual range detection is met, it is not met otherwise. Probability q The median troposcatter transmission loss under is: (2) Where F is the meteorological factor, f is the signal frequency, d is the path length, θ is the scattering angle, L N is the transmission loss term related to the common scatterer height, L c is the antenna dielectric coupling loss, The transmission reliability is q The depth of the fade; According to formulas (1) and (2), the distance reconnaissance equipment d The probability of over-the-horizon reconnaissance of the radar at the location satisfies the conditions of formula (3). q value: (3) Approximate the calculation of q value by bisection method; S2, multiplying the plurality of reconnaissance probabilities to obtain the over-the-horizon reconnaissance positioning probability of the radar by the multiple reconnaissance stations.

2. The method for calculating the probability of over-the-horizon radar reconnaissance and positioning based on tropospheric scatter according to claim 1, characterized in that: The method of approximating and calculating the q value by bisection includes the following sub-steps: First determine the path length d Is it within the tropospheric scatter propagation range? If not, the calculation conditions are not met; If yes, then calculate the following conditions 1 and 2: Condition 1: Calculate according to formula (2) q =0 ,judge Is it true? If it is true, the calculation condition is not met and the calculation ends; Condition 2: Calculate according to formula (2) q =100 ,judge Is it true? If true, the probability is 100% and the calculation ends; When conditions one and two are not met, the q Loop through (0,100) to find the value until the condition in formula (5) is met. ;in is the set error threshold; (5) 3. The method for calculating the probability of radar over-the-horizon reconnaissance positioning based on tropospheric scatter according to any one of claims 1 or 2, characterized in that: In step S2, the sub-steps are included: S21, calculate the probability of each reconnaissance station to the radar beyond the visual range according to the calculation method in step S1 ; S22, when multiple reconnaissance stations locate radar beyond visual range, each reconnaissance station is required to intercept the radar signal, then the positioning probability is the product of multiple reconnaissance probabilities .

4. The method for calculating the probability of over-the-horizon radar reconnaissance and positioning based on tropospheric scatter according to claim 1, characterized in that: Ls Dynamic changes, and Ls It is a probability statistical value of a semi-empirical formula obtained based on local test data.

5. The method for calculating the probability of radar over-the-horizon reconnaissance and positioning based on tropospheric scatter according to claim 1, characterized in that: F. θ 、 L N 、 L c 、 The calculations are all obtained using existing schemes.

6. The method for calculating the probability of over-the-horizon radar reconnaissance and positioning based on tropospheric scatter according to claim 1, characterized in that: Theoretically, it is related to the following parameters: probability, radio climate zone to which the propagation belongs, height of the transmitter and receiver above the ground, path length, signal frequency, and antenna gain of the transmitter and receiver.

7. The method for calculating the probability of radar over-the-horizon reconnaissance and positioning based on tropospheric scatter according to claim 2, characterized in that: The upper limit of the tropospheric scatter propagation range is related to the highest altitude of the scatterer, and the lower limit of the tropospheric scatter propagation range is the line of sight between the transmitter and receiver.

8. The method for calculating the probability of over-the-horizon radar reconnaissance and positioning based on tropospheric scatter according to claim 7, characterized in that: The upper limit of the tropospheric scatter propagation range is between 1100 and 1200 km.

9. The method for calculating the probability of radar over-the-horizon reconnaissance and positioning based on tropospheric scatter according to claim 7, characterized in that: The lower limit of the tropospheric scatter propagation range is the line of sight between the transmitter and receiver, and the calculation method is formula (4); (4) Where, and are the altitudes of the radar and reconnaissance stations respectively.

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