General description of the components of the radar model. Mathematical model of radar

2.2 Mathematical model of radar

As already noted in paragraph 1.1, the main radar modules are the antenna unit, together with the antenna switch, transmitter and receiver. A large class of various devices can be used as a terminal device, differing in the way they display information and not affecting the received radar signals, so this class of devices is not considered.

2.2.1 Mathematical model of the antenna

One of the main characteristics of the antenna is its directional pattern (DDP) /5/, which characterizes the dependence of the radiated power on the direction (Figure 2.3).

Figure 2.3 – Antenna power pattern

The antenna radiation pattern in the azimuth-range plane at a constant elevation angle with a uniform field distribution across the aperture is expressed by the function:

(14)

The angle β for uniform motion of the antenna in a circle can be found using the formula:

(15)

where ω is the angular speed of rotation of the antenna, rad/s.

Let's consider the shape of the reflected signal in a 360-degree radar. As the antenna rotates, the amplitude of the probing pulses irradiating the target changes in accordance with the radiation pattern. Thus, the probing signal irradiating the target turns out to be modulated and described by a function of time

where s P (t) – radio pulses of the transmitter.

Let us assume that the target practically does not change the duration of the reflected pulses, and that the movement of the target during the irradiation time can be neglected. Then the reflected signal is characterized by the function:

where k is a constant coefficient.

For a single-antenna radar, in which the antenna radiation pattern during reception is described by the same function F E (t) as during transmission, the signal at the receiver input is written in the form:

Because the antenna rotation speed is relatively low and the beam displacement during the delay time is much less than the width of the radiation pattern, then F E (t)≈F E (t – t W). In addition, a function characterizing the power radiation pattern:

(19)

where β is the angle measured in one direction from the maximum to the target azimuth, degrees;

Θ 0.5 – width of the radiation pattern at half power, measured in both directions from the maximum (Figure 2.3), degrees.

Taking into account the above, (17) can be represented as:

those. The pulses at the receiver input are modulated in amplitude in accordance with the power directional pattern of the antenna.

The target azimuth is determined by the parameters of the angle-code converter sensor (Figure 2.4).

Figure 2.4 – Scheme for connecting the angle-code converter sensor

When the antenna rotates, the signals from the photo emitter are recorded by the photo receiver after the signals pass through holes in the plate located on the axis of the antenna. Signals from the photodetector are transmitted to the counter, which generates pulses called MAI pulses (short azimuth intervals). The angle of rotation of the antenna, and, consequently, the azimuth of the received radar signal is determined by the MAI pulses. The number of MAI coincides with the meter's conversion factor and determines the accuracy with which azimuth is measured.

Based on the above, the antenna module is characterized by the following parameters: the shape of the radiation pattern and its width, the antenna gain, the number of MAIs.

2.2.2 Mathematical model of the transmitting device

The transmitting device can be characterized by the radiation power, the number and type of probing signals and the law of their arrangement.

The range of the radar in the case of optimal signal processing and a given spectral noise density depends on the energy of the probing signal, regardless of its shape /5/. Considering that the maximum power of electronic devices and antenna-feeder devices is limited, an increase in range is inevitably associated with an increase in pulse duration, i.e. with a decrease in potential range resolution.

Complex or power-intensive signals resolve conflicting demands for increased detection range and resolution. Detection range increases when using high energy signals. An increase in energy is possible by increasing either the power or the duration of the signal. The power in a radar is limited from above by the capabilities of the radio frequency generator and especially by the electrical strength of the feed lines connecting this generator to the antenna. Therefore, it is easier to increase the signal energy by increasing the signal duration. However, long duration signals do not have good range resolution. Complex signals with a large base can resolve these contradictions /7/. Currently, frequency-modulated (FM) signals are widely used as one of the types of complex signals.

The entire set of FM signals can be described using the formula:

(21)

where T is the pulse duration, s;

t – time, function argument, varies within , c;

b k – coefficients of signal phase series expansion;

f 0 – signal carrier frequency, Hz.

Indeed, with n = 1 we obtain a linearly frequency-modulated (chirp) signal, whose coefficient b 0 - the signal base - can be found as:

(22)

where Δf is the frequency deviation of the chirp signal, Hz.

If we take n = 1 and frequency deviation Δf = 0 Hz, we obtain a MONO signal or video pulse with a rectangular envelope, which is also widely used in radar for detecting targets at short distances.

Another way to increase the signal energy while maintaining a short pulse duration is to use bursts of pulses, i.e. a series of pulses separated by interpulse intervals is considered as a single signal. In this case, the signal energy is calculated as the sum of the energies of all pulses /7/.

The P-15 (P-15MN) radar station of the decimeter wave range was intended to detect targets flying at medium, low and extremely low altitudes. Entered service in 1955. It was used as part of radar posts of radio engineering units and as a reconnaissance and target designation station for anti-aircraft missile units.

The P-15 station was mounted on one vehicle along with the antenna system and was deployed into a combat position in 10 minutes. The power supply unit was transported in a trailer.

Model from ZZ MODELL, the base vehicle ZIL-157 was supplied (most likely) from ICM and is made of plastic, in my opinion, not bad at all. There was no particular hassle during assembly. Kung resin station. During the assembly process it was necessary to tinker with the fit of the rear wall (where the double doors are). The jacks are also made of resin and are quite fragile; one broke. The antenna-feeder system is made of photo-etched material.

The model was painted with Tamia Color acrylic paints, and the whole thing was blown over with Humbrol matte varnish.

From the modifications to the model presented to you, I decided to do the following:

• tool boxes located under the rear wall of the kung on both sides;
• the second fuel tank of the car (there is only one included with the model for some reason unknown to me);
• rear license plate mount;
• waveguide on the upper antenna feed;
• the bottom step to the ladder on the rear side wall of the kung.

I didn’t lift it high on jacks, because... According to the instructions - still Soviet - it is enough only for the wheels of the suspended equipment to turn if it is located on a hard surface. There is also such a thing as to preserve rubber in the summer, the wheels are painted white. Although in my practice I have seen painted wheels a couple of times.

Of the shortcomings I noticed in the assembly diagram, I noticed one little thing. In the circuit, the feed holders of the upper and lower antennas are attached in the same way - with tubes to which the radio frequency cable is attached downwards. Although in a real station, on the lower antenna, it is mounted in reverse (see photo). I noticed this thing by accident when trying to imitate a radio frequency cable, when everything was already assembled. The lower waveguide part of the lower photo-etched antenna is also not made accurately - it does not correspond to the original, it had to be corrected.

As for the degree of correspondence of the entire model to the original, I was quite satisfied with it. Although there is some work to be done.

1

This article presents a model for the functioning of a VHF long-range radar station under the influence of natural passive interference caused by the dissipation of radiated energy on inhomogeneities in the electron concentration of the E-layer of the ionosphere (auroral inhomogeneities of northern latitudes and magnetically oriented inhomogeneities in the E-layer of the mid-latitude ionosphere). A feature of the presented model is that it takes into account the specifics of the occurrence of these passive interferences. The procedure for modeling the detection of reflections from magnetically oriented irregularities in the ionospheric E-layer is considered. As an example, the results of simulation modeling of the impact on a VHF long-range radar station with a phased antenna array of reflections from magnetically oriented irregularities in the E-layer of the mid-latitude ionosphere, differing in size and electron concentration, are shown. The proposed model can be used in the development of software intended for testing early warning radar stations.

1. Bagryatsky B.A. Radar reflections from polar lights // Advances in Physical Sciences. – Vol. 2, t. 73. – 1961.

2. Dolukhanov M.P. Propagation of radio waves: textbook for universities. – M.: Communication, 1972. – 336 p.

3. Mizun Yu.G. Propagation of radio waves at high latitudes. – M.: Radio and Communications, 1986. – 144 p. ill.

4. Modeling in radar / A.I. Leonov, V.N. Vasenev, Yu.I. Gaidukov and others; edited by A.I. Leonova. – M.: Sov. radio, 1979. – 264 p. with ill.

5. Sverdlov Yu.L. Radar studies of anisotropic small-scale irregularities in the polar ionosphere: dis. ...Dr.Tech. Sci. – Murmansk, 1990. – 410 p.

6. Handbook on radar: trans. from English under general editorship V.S. Willows / ed. M.I. Skolnik. In 2 books. Book 1. – M.: Tekhnosphere, 2014. – 672 p.

7. Theoretical foundations of radar / ed. V.E. Dulevich. – M.: Sov. radio, 1964. – 732 p.

8. Physics of auroral phenomena. – L.: Nauka, 1988. – 264 p.

9. Physics of the ionosphere / B.E. Brunelli, A.A. Namgaladze. – M.: Nauka, 1988. – 528 p.

Interference caused by the dissipation of radiated energy on inhomogeneities in the electron concentration of the E region of the ionosphere (auroral inhomogeneities (AN) of northern latitudes and magnetically oriented inhomogeneities (MON) of the E-layer of the mid-latitude ionosphere) have a significant impact on the quality of operation of the long-range detection radar (EAR radar) range VHF. The presence of interference leads to overload of the primary signal processing system, the formation of false trajectories and a decrease in the specific share of energy spent on servicing real objects.

The article presents an approach to modeling the functioning of a distance radar under the influence of natural passive interference caused by the influence of the ionosphere.

The observed radars of the BS of the northern latitudes and the MON E-layer of the mid-latitude ionosphere, as a rule, are in the altitude range of 95-125 km, while the thickness of the layer of inhomogeneities is 0.5-20 km, and their longitudinal and transverse dimensions can be up to several hundreds of kilometers.

The results of experimental studies of auroral interference and radio reflections from the MON E-layer of the mid-latitude ionosphere showed that even relatively small scattering volumes (no more than one cubic kilometer) contain an ensemble of “pseudo-independent” reflectors moving relative to each other. Accordingly, the amplitude of the resulting reflected signal is a superposition of a large set of components corresponding to elementary waves with their own scattering centers (random amplitudes and phases).

All ionospheric irregularities located within the general volume and irradiated by the transmitting antenna become sources of scattered radiation that affects the receiving antenna. The signal power at the input of the receiving antenna, created by the scattering volume, is determined by the formula:

where P And - radiated power, W; D1 and D2 - directivity coefficients of the transmitting and receiving antennas; λ - wavelength, m; η - loss coefficient due to the propagation environment, imperfections of signal processing paths, etc., 0 ≤ η ≤ 1; r1 and r2 - distances from the transmitter and receiver to the center of the dV element of the scattering region, km; σ′ - specific ESR, is the ratio of the total observed ESR to the value of the pulse volume illuminated by the radar (dimension m2/m3 = 1/m).

When calculating, they usually use not the power of the received signal, but its ratio to the noise power Psh at the radar input - the signal-to-noise ratio (SNR) q = Ppr/Psh.

Combining all the parameters related to the radar into one factor, which is called the radar potential, taking into account that for the radar up to r 1 ≈ r 2, we obtain

In practice, the radar potential is determined based on the results of full-scale experiments by measuring q with known characteristics of the radar and the target. If you have an assessment of the potential, to calculate the SNR from observation objects located at an arbitrary range, it is convenient to use the following formula:

where P 0 is an estimate of the radar potential (a value numerically equal to the SNR from a target with σ eff = 1 m2, located normal to the antenna surface, at a distance R 0); R is the range for which the SNR is calculated, km.

Expression (2), taking into account the deviation of the phased antenna array beam in the azimuthal and elevation planes from the antenna normal, as well as taking into account the position of the scattering volume relative to the maxima of the antenna radiation patterns, takes the form

where is a function that takes into account the change in potential depending on the deviation of the radiation pattern from the normal; α 0, β 0 - the value of azimuth and elevation angle corresponding to the maximum potential; α, β - current values ​​of azimuth and elevation angle of the signal source.

Functions that take into account the change in signal magnitude depending on the position of the center of the scattering volume relative to the maximum of the radiation pattern of the transmitting (receiving) antennas for radars with phased array

where N H, N V - the number of emitters within the antenna horizontally and vertically; s - grating pitch, m; λ - radar wavelength, m; α n, β n - angles of deviation of the center of the elementary volume from the normal; α x, β x - angles of deviation of the maximum radiation pattern in azimuth and elevation from the normal.

Specific EPR of the ionization region

where k = 2π/λ (λ is the radar wavelength); χ is the angle between the electric vector of the incident wave and the wave vector of the scattered wave; T - transverse correlation radius (relative to the x and y axes), m; L - longitudinal (relative to the z axis) correlation radius, m; is the mean square of electron density fluctuations in the scattering region; λ N - plasma wavelength, m; θ is the angle between the wave vector of the incident and scattered waves; ψ is the angle between the wave vector of the incident wave and the plane normal to the z axis (foreshortening angle).

The aspect angle ψ is determined by the relation

where Hx, Hy, Hz are the components of the geomagnetic field at the point of reflection, respectively, along the x, y, z axes directed to the north, east and to the center of the Earth. The values ​​of Hx, Hy, Hz are calculated in accordance with the selected model of the Earth's geomagnetic field, for example IGRF (International Geomagnetic Field);

rx, ry, rz - the corresponding components of the wave vector (calculated based on the coordinates of the radar dislocation);

Considering that DL radars record backscattering, i.e. χ = 90°, and θ = 180°, we have

(4)

As can be seen from (3) and (4), the antiderivative of the integrand in (3) is not expressed through analytical functions and the SNR values ​​can be obtained by numerical integration.

Assuming that the values ​​of L, T, , λ N within the scattering volume during the irradiation time have a constant value, we obtain

where n is the number of elementary volumes ΔV i into which the total scattering volume of the ionization region V is divided.

To estimate from above the value of the scattering volume of the MON E-layer of the ionosphere, you can use the expression for the allowed volume of the radar:

where R is the distance to the center of the scattering volume; Δα, Δβ, ΔR - radar resolution in azimuth, elevation, range.

Analysis of the factor in (5) shows that it makes a significant contribution only for those values ​​of T2 that are close to , while

Taking into account the assumption made

Let us consider the procedure for modeling the functioning of a BS radar under the influence of EPP caused by the MON of the E-layer of the ionosphere.

The position and dimensions of the scattering region (AN, MON E-layer of the mid-latitude ionosphere) in the coverage area of ​​the BS radar are specified by: the geographic coordinates of the center; longitudinal and transverse dimensions; layer height and thickness.

For each detected signal, a mark is generated in the radar station. A mark is understood as a set of numerical discrete characteristics obtained by processing the received echo signals. The specific set of characteristics that make up the mark depends on the type of radar. Typically, the mark includes estimates of range, azimuth, elevation, signal amplitude (power), and radial velocity for radars measuring the Doppler frequency shift of the received signal.

When viewing one angular direction for each measuring beam, the SNR is calculated using formula (7). Calculations are carried out taking into account the following considerations.

The dimensions of elementary volumes must be chosen so that within their limits the aspect angle remains practically unchanged. To obtain satisfactory SNR accuracy, the angular dimensions ΔV i (in azimuth Δε e and elevation angle Δβ e) should not exceed 0.1°. Based on this, in each allowed range element the beam is divided into elementary volumes. For each center ΔV i, the geographic coordinates and height (φ, λ, h) are calculated. The summation in formula (7) is carried out over elementary volumes whose center (φ, λ, h) belongs to the scattering region. The value of ΔV i is calculated similarly to (6).

The values ​​of , λ N and L included in formula (7) can be obtained by generalizing experimental studies published in.

The probability density distribution of the amplitude of the signal reflected from the AN and MON of the mid-latitude ionosphere is described by the Rayleigh law, and the power by the exponential law. The Doppler frequency shift of the reflected signal (for DL ​​radars that perform the corresponding measurement) is modeled by a random variable that has a normal distribution with zero mathematical expectation and standard deviation equal to 1 kHz.

Obtaining estimates of azimuth and elevation angle is carried out in accordance with the operating algorithms of a specific radar station.

In Fig. 1 and 2 show the results of modeling marks in different planes, when located in the radar coverage area of ​​up to two different MON E-layers.

Rice. 1. Simulation results (heterogeneity No. 1)

Rice. 2. Simulation results (heterogeneity No. 2)

Initial data from the radar: coordinates of the standing point: 47° N, 47° E; azimuth of the bisector of the coverage area 110°; width of the coverage area in azimuth 120°, in elevation 16°; radiation pattern width in azimuth 1.5°, elevation 1.5°; ΔR = 300 m; radar potential 40 dB; detection threshold 15 dB; the operating wavelength of the radar is 0.8 m. To estimate the angular coordinates in each coordinate plane, two intersecting radiation patterns are formed, spaced by the same amount from the equal-signal direction - the intersection point of the patterns (rays). The beam spacing value is equal to half the beam width at half power level. 15 cycles of viewing the coverage area were simulated.

Parameters of ionospheric irregularity No. 1: the center is located at a point with coordinates 50.4°N, 58.7°E; altitude 105 km; altitude thickness 3 km; longitudinal dimension 5 km; transverse dimension 5 km; L = 10 m; λ N = 75 m.

Parameters of ionospheric irregularity No. 2: the center is located at a point with coordinates 50.4 °N, 58.7 °E; altitude 117 km; altitude thickness 3 km; longitudinal dimension 5 km; transverse dimension 25 km; L = 10 m; λ N = 75 m.

Analysis of the obtained results showed that, by varying the parameters of ionospheric irregularities, it is possible to obtain marking parameters similar to the parameters obtained experimentally during the operation of the BS radar under conditions of exposure to ionospheric interference.

The proposed model for the operation of DL radars under conditions of natural passive interference caused by reflections from the ionosphere takes into account the features of the physical processes that determine the specifics of their occurrence.

The model makes it possible to evaluate algorithms for the operation of DL radars under conditions of passive interference caused by the influence of the ionosphere, and can be used in the development of software intended for testing BL radars.

Bibliographic link

Azuka K.K., Stolyarov A.A. SIMULATION OF THE OPERATION OF A VHF LONG RANGE DETECTION RADAR UNDER CONDITIONS OF NATURAL PASSIVE INTERFERENCE DUE TO THE INFLUENCE OF THE IONOSPHERE // Fundamental Research. – 2016. – No. 6-1. – P. 9-13;
URL: http://fundamental-research.ru/ru/article/view?id=40362 (access date: November 25, 2019). We bring to your attention magazines published by the publishing house "Academy of Natural Sciences"

Latest update of the description by the manufacturer 21.09.2018

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Film-coated tablets	1 table
active substances:
ethinylestradiol	0.03 mg
drospirenone	3 mg
excipients (core): lactose monohydrate - 43.37 mg (the amount of lactose monohydrate may vary depending on the purity of the active substance substance); corn starch - 12.8 mg; pregelatinized starch - 15.4 mg; povidone-K25 - 3.4 mg; croscarmellose sodium - 1.6 mg; magnesium stearate - 0.4 mg
Excipients (shell): Opadry yellow 03B38204 (hypromellose 6cP - 62.5%, titanium dioxide - 29.5%, macrogol 400 - 6.25%, yellow iron oxide dye - 1.75%) - 2 mg

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pharmachologic effect- contraceptive, estrogen-gestagenic.

Directions for use and doses

Inside. The tablets should be taken in the order indicated on the package, at approximately the same time every day, with a small amount of water.

You should take 1 tablet. continuously for 21 days. Taking the tablets from the next package begins after a 7-day break, during which menstrual-like bleeding (withdrawal bleeding) is usually observed. As a rule, it begins on the 2-3rd day after taking the last pill and may not end until you start taking pills from a new package.

Start taking MODELL ® PRO. If you have not taken any hormonal contraceptives in the previous month, the use of MODELL ® PRO should begin on the 1st day of the menstrual cycle (i.e., on the 1st day of menstrual bleeding). It is possible to start taking it on the 2-5th day of the menstrual cycle, but in this case it is recommended to additionally use a barrier method of contraception during the first 7 days of taking the tablets from the first package.

Switching from other COCs, vaginal ring or contraceptive patch. It is preferable to start taking MODELL PRO the day after taking the last tablet from the previous package, but in no case later than the next day after the usual 7-day break. Taking MODELL ® PRO should begin on the day the vaginal ring or patch is removed, but no later than the day when a new ring is to be inserted or a new patch is applied.

Switching from contraceptives containing only gestagens (mini-pills, injectable forms, implant or IUD with controlled release of gestagen). You can switch from a mini-pill to taking MODELL ® PRO on any day (without a break), from an implant or IUD - on the day of their removal, from an injectable contraceptive - on the day when the next injection is due. In all cases, it is necessary to use an additional barrier method of contraception during the first 7 days of taking the pills.

After an abortion in the first trimester of pregnancy, you can start taking the drug immediately - on the day of the abortion. If this condition is met, the woman does not need additional methods of contraception.

After childbirth or abortion in the second trimester of pregnancy. It is recommended to start taking the drug on the 21-28th day after childbirth (in the absence of breastfeeding) or abortion in the second trimester of pregnancy.

If use is started later, it is necessary to use an additional barrier method of contraception during the first 7 days of taking the pills. If sexual contact has taken place, then before starting to take the drug MODELL ® PRO, you should exclude pregnancy or wait until your first menstruation.

Taking missed pills. If the delay in taking the drug is less than 12 hours, contraceptive protection is not reduced.

You should take the tablet as soon as possible, and take the next tablet at the usual time. If the delay in taking the drug is more than 12 hours, contraceptive protection may be reduced. The more pills are missed and the closer the missed pill is to the 7-day break in taking pills, the greater the likelihood of pregnancy. In this case, you can be guided by the following two basic rules:

The drug should never be interrupted for more than 7 days;

To achieve adequate suppression of the hypothalamic-pituitary-ovarian axis, 7 days of continuous tablet use are required. Accordingly, if the delay in taking the pills is more than 12 hours (the interval since the last pill was taken is more than 36 hours), the woman should follow the recommendations given below.

The first week of using the drug. The last missed pill should be taken as soon as possible, as soon as the woman remembers (even if this means taking two pills at the same time). The next tablet is taken at the usual time. Additionally, you should use a barrier method of contraception (such as a condom) for the next 7 days. If sexual intercourse took place during the week before missing the pill, the possibility of pregnancy must be taken into account.

Second week of using the drug. The last missed pill should be taken as soon as possible, as soon as the woman remembers (even if this means taking two pills at the same time). The next tablet is taken at the usual time. Provided that the woman has taken the pills correctly for the 7 days preceding the first missed pill, there is no need to use additional contraceptive measures.

Otherwise, or if you miss two or more tablets, you must additionally use barrier methods of contraception (for example, a condom) for 7 days.

Third week of using the drug. The risk of pregnancy increases due to the upcoming break in taking the pills. You should strictly adhere to one of the following two options. However, if during the 7 days preceding the first missed pill, all pills were taken correctly, there is no need to use additional contraceptive methods. Otherwise, you must use the first of the following regimens and additionally use a barrier method of contraception (for example, a condom) for 7 days.

1. It is necessary to take the last missed pill as soon as possible, as soon as the woman remembers it (even if this means taking two pills at the same time). The next tablets are taken at the usual time until the tablets in the current pack run out. The next pack should be started immediately without interruption.

Withdrawal bleeding is unlikely until the second pack is finished, but spotting and breakthrough bleeding may occur while taking the tablets.

2. You can also stop taking tablets from the current package, thus starting a 7-day break (including the day you missed tablets), and then start taking tablets from a new package. If a woman misses taking pills and then does not have withdrawal bleeding during the break, pregnancy must be ruled out.

Recommendations in case of gastrointestinal disorders. In case of severe gastrointestinal disorders (vomiting, diarrhea), absorption may be incomplete, so additional methods of contraception should be used. If vomiting occurs within 3-4 hours after taking the tablet, you should follow the recommendations for skipping tablets. If a woman does not want to change her usual dosing regimen and move her menstrual cycle to another day of the week, an additional tablet should be taken from a different package.

Changing the day of the start of the menstrual cycle. In order to delay the onset of menstruation, it is necessary to continue taking tablets from the new MODELL ® PRO package without a 7-day break. Tablets from the new package can be taken for as long as necessary, incl. until the packaging runs out. While taking the drug from the second package, spotting from the vagina or breakthrough uterine bleeding are possible. You should resume regular use of MODELL ® PRO from the next package after the usual 7-day break. In order to postpone the onset of menstruation to another day of the week, a woman should shorten the next break in taking pills by the desired number of days. The shorter the interval, the higher the risk that she will not have withdrawal bleeding and will subsequently experience spotting and breakthrough bleeding while taking the second pack (just as if she would like to delay the onset of menstruation).

Additional information for special categories of patients

Use in children. The effectiveness and safety of the drug as a contraceptive have been studied in women of reproductive age. It is assumed that the effectiveness and safety of the drug in post-pubertal age up to 18 years are similar to those in women after 18 years. The use of the drug before menarche is not indicated.

We have previously looked at models of radar stations.

Today I would like to present you with a review of the P-18 Terek radar model (1RL131), in 1/72 scale. Like the previous ones, it is produced by the Ukrainian company ZZ model. The set has catalog number 72003, and is packaged in a small soft cardboard box with a removable top.

Inside there are plastic parts, resin parts, photo-etched parts and instructions.

It is based on a plastic model of the Ural flatbed truck from ICM , most of it comes from it. This model has already been considered several times, all the shortcomings and methods for eliminating them were analyzed in detail, so I see no point in repeating myself. We can only say that the correct cabin and wheels are manufactured by Tankograd.

Some elements of the traverse and antenna struts are also made of plastic. But I didn’t really like their quality; it’s better to replace these parts with wire of a suitable cross-section.

The resin is used to make a metal car van with an antenna mast device (AMU), side supports, and an antenna drive gearbox.

There are no special complaints about the resin parts, there is a small amount of flash, there are no displacements or cavities.

The kit contains two photo-etched boards, which mainly contain elements of the P-18 radar antenna.

The quality of the etching is not satisfactory, but it is worth considering that the antenna directors have a round cross-section, but here, due to technology costs, a square cross-section is obtained.

In principle, you can leave these nodes as is, but you can make a conductor and solder the directors from wire, and of different diameters. The mast itself, a real P-18 radar, is assembled from corners with flat reinforcement elements. This moment is correctly conveyed by photo-etching.

The instructions, by today's standards, are very primitive. And upon closer examination, some stages of assembly raise questions. I would like the manufacturer to show in more detail the assembly of such a complex unit as the P-18 radar antenna.

To resolve most of the questions regarding materiel, I took a fairly detailed photo review walkaround at the AvtoVAZ Technical Museum in Tolyatti.

It is also worth adding that the P-18 Terek radar (1RL131) consists of two vehicles: a hardware one, with a K-375 body, and a vehicle with an AMU, which we are now considering. When working on a model, it’s worth taking this into account and making two cars at once. When working on a hardware vehicle, it is necessary to take into account the location and size of hatches on the body. To do this, you need to find good photos, and, if possible, take measurements of this product.

In conclusion, it is worth noting that this model is clearly not for beginner modelers and to get a decent result, you should stock up on time and patience. Its price in online stores is about $40, which is ultimately not little, given the current dollar exchange rate.