RU2558407C2 - Detection of air target inclined range by target specified speed - Google Patents

Abstract

FIELD: weapons and ammunition.

SUBSTANCE: invention relates to methods and means for aiming and guidance used in the Army self-propelled AA mount (SAM). Proposed method can be used in case the mount ranging radar fails or for jamming. Mount optical sight is used to measure the current angular coordinates of air target. Radar of the reconnaissance and control mobile station (RCMS) sets target linear speed and azimuth to be transmitted via radio line to target designation receive-and-process hardware. Available specimens of said hardware are incorporated with said SAM. Data measured at SAM and transmitted from RCMS are loaded to digital computer to compute inclined range to target by appropriate formulae.

EFFECT: higher precision of inclined range determination, hence higher accuracy of fire.

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Description

The invention relates to the field of armament and can be used in anti-aircraft self-propelled units of the ground forces in the conditions of inoperability of the measuring system of the range of the radar system.

The closest in technical essence to the claimed invention is a method implemented in a self-propelled anti-aircraft gun (ZSU) 2S6M anti-aircraft gun-missile complex (SAM) 2K22 [1, 2, p.26-28].

ZSU 2S6M contains a tracked chassis GM-352, a turret with missile and cannon armaments, power hydraulic actuators for controlling weapons, radars, a digital computer system (CVS), a system for measuring angles of quality, an optical sight (OP) with a guidance and stabilization system, equipment for detecting missile coordinates and other auxiliary systems. The radar system includes a radar station for detection and target designation (SOC), a radar target tracking station (SSC) and a ground-based radar interrogator.

For shooting at air targets in various conditions of air and interference conditions, as well as depending on the availability of optical visibility, the ZSU 2S6M provides various operating modes [1]. Combat work on the ZSU 2S6M in these modes occurs as follows [2, p.26-28].

In the first mode, which is called "All data from the radar system" and which is used when firing anti-aircraft guns, the SOC performs a radar method of a circular overview of airspace. Information about the detected targets is displayed on the circular visibility indicator (IRF) in the form of brightness marks. If there is no “own” mark from the target on the SOC all-round viewing indicator screen, the ZSU operator combines the target designation marker with the mark from the target. In this case, the DAC at the marker position generates control signals in azimuth and slant range and transmits them to the SSC. Based on these signals, the SSC antenna is set to the specified azimuth (if the mismatch in azimuth exceeds 50 °, the hydraulic actuator rotates the turret), and the range gate is set to the indicated inclined range. Observing on the indicator screen “range-azimuth-elevation angle” a visible mismatch between the elevation from the target and the line of sight, the operator rotates the helm of the elevation angle. In this case, the antenna control system generates signals that control the pointing of the CCS antenna in elevation. Next, the operator, observing on the range screen a visible discrepancy between the mark from the target and the range strobe (sight), rotating the range control combines the sight with the mark from the target. In this case, the range gate is set to the inclined range D corresponding to the inclined range to the target. After performing these steps, the operator captures the target for auto tracking in angular coordinates and inclined range by pressing the "Aut" button. After capturing the target and taking it for auto tracking, the CVC calculates the projectile meeting point for the target and generates hydraulic actuator control signals by which the ZSU anti-aircraft guns are installed on the shot line.

The second mode is called "Range from the radar, angular coordinates - from the optical sight." The mode is used in conditions of optical visibility when firing a rocket or anti-aircraft guns. In this mode, the operator captures the target for auto tracking along an inclined range, as in the first mode. The target is tracked by angular coordinates by the gunner, who, observing the target in the optical sight, combines the reticle with the visible silhouette of an air target. The aiming mark is two concentric circles of various diameters. The silhouette of the air target should be within the circle of small diameter. If the silhouette of the air target deviates from the aiming mark, the gunner shifts the handle of the joystick mechanism in the direction and by the amount corresponding to this deviation. In this case, the guidance system of the optical sight generates signals that control the angular position of the optical axis of the optical sight. The oblique range (from the radar) and the angular coordinates (from the optical sight) are received in the CVS. Based on the law of changing the range and angular coordinates over a certain period of time and assuming the linearity of the target’s movement, the projectile’s meeting point with the target is calculated and hydraulic control signals are generated. In this mode, rocket fire is possible. In this case, guidance commands are formed by the DAC and transmitted to the missile by the antenna-waveguide system of the target tracking station.

The third mode is called "Inertial tracking." The spherical coordinates of the target (when tracking the target in the first or second modes) are received in the CVS, where the target trajectory is extrapolated. The hypothesis of uniform and rectilinear movement of the target is also used. Due to the accumulation (i.e. gradual increase) of errors in tracking an air target in angular coordinates and range, this mode lasts 20 seconds, and then automatically turns off.

The fourth mode is called "Determining the range of a target by its set speed." This mode is used in case of failure of range measuring systems that are part of the SSC and SOC, or when jamming, leading to the inoperability of these radars. In this mode, an air target is observed in the optical sight, and then its type is visually (i.e., according to the apparent silhouette of the target). It is clear that the regime is operational only in conditions of good visibility of the air target and distinguishing elements of its glider. According to the type of target (taking into account the experience of tracking targets and knowledge of the typical values of the flight speed of a specific target at a certain height), its speed is determined. For this, the gunner must have knowledge of the speeds of typical aircraft of a potential enemy before starting work on targets. Obtaining such knowledge is a doable task. So, for example [3], the maximum speed of the F-15A at an altitude of 12 km is 2650 km / h, and at an altitude of 300 m - 1470 km / h. The landing speed of such an aircraft is 220 km / h, and the take-off speed at take-off is 260 km / h.

The tactical aircraft A-10-A (USA) has the following characteristics [4]: combat ground speed - 725 km / h; flight speed at an altitude of 1,500 m (with six bombs) - 710 km / h; cruising speed at low altitudes - 550 km / h. The multi-purpose Phantom F-4E aircraft has a range of flight speeds of 200-2350 km / h [5]. And the MiG-19S fighter has the following flight performance characteristics: maximum speed at an altitude of 10 km - 1450 km / h; flight speed with cargo on external suspensions - 950 km / h. Thus, for all typical purposes, there is data on the possible speeds of their flight under certain conditions.

The described mode is auxiliary and is used in case of impossibility to measure the slant range to the target. The effectiveness of automatic shooting in this mode is much lower than in other modes. However, even such firing to a certain extent reduces the effectiveness of enemy air strikes.

The value of the target’s speed corresponding to its type under certain conditions will be called the set speed. The set speed is entered into a digital computer system by dialing its numerical value on a digital display using the keyboard. The gunner accompanies the target into the optical sight in the same way as in the second mode. In this case, the azimuth β and the elevation angle ε of the optical sight (corresponding to the angular coordinates of the target) from the position sensors of the optical sight enter the DAC. Based on the set speed and angular coordinates at successive time instants, the CVC, using the well-known formulas [6], calculates the values of the slant range D to the target.

The essence of the method implemented in the fourth mode of operation of the ZSU is as follows [2, p.27-28]. After the detection of an air target, they continuously observe this target in the optical sight. In case of deviation of the air target’s silhouette from the aiming mark (representing two concentric circles), the handle (joystick) of the command sensor is shifted in the direction corresponding to the displacement of the target’s silhouette. In this case, the guidance system of the optical sight generates signals corresponding to the direction and proportional to the magnitude of the shift of the joystick. These signals enter the servo system, which with the help of an electric drive changes the angular position of the optical axis of the sight. By influencing the joystick of the command sensor, the reticle is combined with the silhouette of the air target. Visually determine the type of air target and the average speed corresponding to this type (the so-called set speed) of such an air target. Using the numeric keypad, the target speed value (set speed) is entered into the DAC. Using sensors associated with the optical sight drive, at successive times (with an interval of 1 s), the elevation angle ε and the azimuth β of the line of sight of the air target are measured, which moves from point A ₁ to point at time t _i-1 and t _i A ₂ (figure 1).

Using the CVC, the oblique range D _{i of the} air target is calculated at the i-th time point using the set speed V _{y of the} air target and increment of the angular coordinates of the line of sight using the known formulas [6, p. 54- 55]:

where ε _i , ε _i-1 , β _i , β _i-1 - elevation angle ε and azimuth β of the line of sight at the i-th and the corresponding (i-1) th time points, rad; d _i - the horizontal range of the air target at the i-th point in time, m; V _y - the set speed of the air target, m / s; D _i - the inclined range of the air target at the i-th time, m; Δt is the time interval between adjacent measurements, s.

The relative position of the ZSU (point O) and the target in the horizontal plane are shown in Fig.2. Each ZSU has a senior manager assigned a responsibility sector, within which the ZSU searches for and destroys air targets. The responsibility sector is determined by the angular position of the left and right borders of the sector relative to the north.

The sequence of operations of the known method does not take into account the angle of the target’s course Q _c (the angle counted clockwise from the northern direction to the horizontal projection of the aircraft speed vector). Since there is no information about the target’s course angle Q _c in the ZSU, it was always previously assumed that the air target’s velocity vector is parallel to the bisector of the responsibility sector (i.e., it was assumed that the ZSS works on air targets flying only towards the ZSU position).

However, air targets may have an arbitrary course angle Q _c . To characterize the angular position of the air target’s velocity vector relative to the bisector of the responsibility sector, we introduce the concept of the oblique angle of an air target. The oblique angle of the target (α) is the acute angle measured from the bisector of the sector of responsibility to the horizontal projection of the velocity vector of the air target. Counting clockwise determines negative values of the bevel angles, counting counterclockwise determines positive values. So, in figure 2, the air target C ₁ moves with a bevel angle α = 0, and the target C ₂ with a positive bevel angle α ≠ 0. The bevel angle α is determined by the formula

where θ is the angle between the north direction and the continuation of the bisector of the responsibility sector (the responsibility sector for each ZSU is determined by the senior chief) drawn through the ZSU standing point (point O) in the direction opposite to the location of the air target; Q _c - the value of the angle of the course of the air target (figure 2).

As can be seen from the drawing, with equal values of the speed of air targets and equal angular speeds of the line of sight, but with different bevel angles α, the actual horizontal distance to the target will be different. That is, the neglect of the course angle of the air target leads to an error in determining the distance to this air target.

In all modes, the availability of information about the inclined range D to an air target is a prerequisite for firing, since the coordinates of the meeting point of the projectile or missile with the target are calculated from the range and angular coordinates using the CVC. In the absence of information about the inclined range to the target D, the coordinates of the meeting point may not be calculated correctly, which will lead to a significant deviation of the projectile tracks from the air target. As a result, firing of ZSU with anti-aircraft guns will be ineffective.

Let us evaluate the error of the known method [2, p.27-28] determining the slant range of an air target by its set speed. To do this, we derive an expression for the horizontal range of an air target, taking into account the direction of the air target’s velocity vector (the slant range D is easy to determine, knowing the horizontal range d and elevation angle ε). Let the air target move from point A ₁ to point A ₂ with speed V and a known bevel angle α (Fig. 3). Target speed is determined by its type and called set speed V _y.

The azimuth values β ₁ and β ₂ (relative to the north direction) of the air target at successive times t _i-1 and t _i are measured using an optical sight with a frequency of Δt = 1 s. During two adjacent measurements, a triangle OA ₁ A ₂ is formed in which the side V _y Δt is known (at Δt = 1 s the side will be equal to V _y ) and all angles. The diagram shows the angle θ counted from the northern direction to the continuation of the bisector of the sector of responsibility drawn through the ZSU standing point in the direction opposite to the location of the air target. Required to determine the direction d ₂ (horizontal distance to an airborne target at the final moment of measurement). Using the sine theorem, we obtain:

where Δβ = β ₂ -β ₁ (increment of the angle of view); Δt is the period of measurement of angular coordinates equal to 1 s.

Hence we obtain the expression for a finite oblique range of the form

When the skew angle of the air target α = 0, the angle of sight β ₁ = 10 °, the angle θ = π, the speed of the air target V _y = 2000 km / h and the increment of the angle of sight Δβ = 1 °, the horizontal distance to the air target is d ₂ = 5500 m

If the bevel angle is α = 20 ° (which is not taken into account in a known manner), then with the same initial data, the horizontal distance to the air target will be d ₂ = 16000 m. That is, the error in measuring the horizontal range only by not taking into account the value of the bevel angle α is δd = 10,500 m. If the error in determining the speed of an air target is 600 km / h (that is, for example, the real speed of an air target is 1,400 km / h, and the speed of 2,000 km / h is entered into the CVC), then at α = 0 horizontal air target range to be d ₂ = 3800 m. That is, the measurement error is horizontal distance δd only due to errors in determining the target air δV is the velocity δd = 1700 m.

Based on the foregoing, the error in determining the slant range to an air target in a known manner [2, p.27-28] is comparable with the size of the affected area by anti-aircraft guns (the distant border of the affected area is 4000 m), which minimizes the effectiveness of hitting an air target.

Thus, the prototype method [2, p.27-28] has the following disadvantages.

1. A significant error in determining the slant range to an air target, due to the neglect of the angle of the course of the air target.

2. A significant error in determining the magnitude of the slant range to an air target, due to an error in determining its speed by silhouette.

The task of the invention is to develop a more advanced method for determining the value of the set speed of an air target of its inclined range in the conditions of inoperability of the radar ranging system.

The problem can be solved on the basis of introducing into ZSU 2S6M equipment for receiving and implementing target designation, which provides for the acquisition of target designation data from a mobile reconnaissance and control center (PPRU). The principle of construction and operation of this equipment is known and described, for example, in [7, p.13a-38].

When implementing the proposed modernization, the ZSU work order for the goals will change accordingly. A mobile reconnaissance and control station will conduct reconnaissance of air targets and measure their linear speed V and course angle Q _{c of the} air target. This information in the form of two numerical values will be transmitted over the radio line [8] using the equipment for receiving and implementing target designation on the ZSU. The linear velocity of the target V, measured by the ballast, has the meaning of the set speed V _y described earlier. The difference is that with the known method, the speed of the target is determined visually by the silhouette of the target, and with the proposed new method, the speed of the target is measured by the ballast, which is assumed by its purpose. Therefore PPRU measured linear speed of the target will also be called the set speed V _y.

Using the optical sight of the ZSU, the angular coordinates of the air target are measured. Based on the data on the linear velocity V _y , the course angle Q _c and the increment of the angular coordinates of the air target at successive times, the DAC calculates the slant range to this air target. To derive the formula for calculating the oblique range, consider the movement of an air target in the horizontal plane (Fig. 4). An air target moves from point A ₁ to point A ₂ at a speed of V _y . The azimuth values of the air target at points A ₁ , A ₂ - respectively β ₁ , β ₂ . Since the coordinates are taken at an interval of 1 s, the distance between the points A ₁ , A _{2 is} identically equal to V _y . We get the triangle OA ₁ A ₂ , where the side OA ₂ = d is the horizontal range of the air target at the end point. This range is also required to be determined (calculated).

According to the sine theorem, we obtain

The angle γ is determined by the formula

Thus, the horizontal range of the air target d is determined by the formula

The oblique range of the target D is determined in accordance with the expression (4)

Next, the slant range of the air target is used to solve the problem of meeting the projectile with the target in the same way as in the known method in the normal mode [6, p. 58-64].

Since the heading angle Q _{c of the} air target is known (measured with the help of the ballast), and the azimuth of the air target is determined by the optical sight relative to the northern direction, the use of the bevel angle α is not necessary.

Define the error in calculating the slant range of the proposed method.

Let us take the error in measuring the speed V _y and the course angle Q _{c of an} air target typical for target tracking radar: δV = 10 km / h and δα = 1 °. Then, at α = 10 °, V _y = 2000 km / h, the inclined range of the air target will be 10 km, and at α = 11 °, V _y = 2010 km / h, the range will be 11400 m. That is, the error in calculating the range is δd = 1400 m, which is significantly less than the error provided by a known method.

The proposed method is as follows.

1. The mobile reconnaissance and command post (SPMS) of the anti-aircraft battalion command post (KP Zdn) conducts reconnaissance of air targets and measures their linear speed V _y and the heading angle Q _{c of the} target. In the case of motion aerial target (group purposes) in the direction of the gun mount, operating in the fourth mode, PPRU transmitted to this SoL via instrumentation value of the selected linear velocity targeting of RL transmission [8] V _y and Q heading angle _c target (group purposes).

2. In the composition of the ZSU enter equipment reception and implementation of target designation, paired (associated information) with the transmission of target designation equipment installed on the control room [9]. The equipment for receiving and implementing target designation can be similar in composition and principle of operation to that described in [7].

3. The values of the set speed V _y and the angle of the course Q _c, adopted with the help of the equipment for receiving and implementing target designation, are redirected to the DAC.

4. When a mark from an air target appears on the circular view indicator, combine a target designation marker (displayed on the PPI as a luminous risk) with a mark from the target. To move the marker control the handle of the joystick mechanism. At the same time, with the help of the DAC, control signals in azimuth are generated at the marker position and transmitted to the tracking system of the optical sight. According to these signals, the optical axis of the sight using the electric drive is set to the specified azimuth β (corresponding to the position of the target designation marker).

5. Observe in the eyepiece of the optical sight scanning of the aiming mark by elevation [2, p.178-179]. When the target appears in the field of view, press the SEARCH button and, acting on the joystick of the command sensor, hold the reticle on the target. In this case, the azimuth β and the elevation angle ε of the air target are measured using sensors of the servo system of the optical sight.

6. The azimuth and elevation angle of the target in the form of electrical signals are transmitted to the DAC, where the oblique range of the air target D is calculated using the following formulas:

where ε _i , ε _i-1 , β _i , β _i-1 - elevation angle ε and azimuth β of the line of sight at the i-th and the corresponding (i-1) th time points, rad; d _i - the horizontal range of the air target at the i-th point in time, m; V _y - installed (measured with the help of the ballast) the speed of an air target, m / s; Δt is the time interval between adjacent measurements, s.

The proposed method differs from the known method [2, p.27-28] by the approach to determining the horizontal distance d to an air target, taking into account the value of the angle of the course Q _{c of the} air target, obtained from the SPMS.

Thus, the application of the new method will significantly improve the accuracy of measuring the slant range to an air target with an inoperative radar range measuring system or in conditions of intense interference that do not allow measuring the slant range. Improving the accuracy of measuring oblique range, in turn, provides an increase in the effectiveness of hitting air targets by more accurately determining the meeting point of the projectile with the target [10]. This method can also be used in other anti-aircraft systems, where in difficult conditions of an interference environment it is impossible or difficult to measure the distance to an air target.

To implement the new method, you must:

introduce into the composition of the ZSU equipment reception and implementation of target designation, similar to [7];

change the standard formulas for calculating the DAC of an inclined range D by formulas (11) - (12).

The method for determining the oblique range of an air target by its installed speed is feasible in anti-aircraft cannon-missile systems, since it does not involve the development of new equipment for the reception and implementation of target designation, but is based on the use of existing equipment [7], and also involves the use of radar information from the existing ballast. In addition, the method is based on a change in the formulas by which information is processed.

The advantage of the proposed method is to significantly increase the accuracy of determining the slant range D of the target (when working in the fourth mode), which increases the accuracy of determining the meeting point of the projectile with the target, which, ultimately, increases the efficiency of firing at an air target. The use of the proposed method in ZSU 2S6M and a similar product will make it possible to increase the efficiency of shelling an air target without significant costs.

Information sources

1. Anti-aircraft self-propelled gun ZSU 2S6M. Technical description. 2C6M.00.00.000 TO, 1991. 80 s.

2. Product 2S6M. User's manual. Part 1. Combat work. 2S6M.00.00.000 IE. 203 p. (p. 27-28 - prototype).

3. Chebotarev I. Combat capabilities of the F-15A fighter / Foreign Military Review. 1977. No. 7. S.48-53.

4. Yezhov N.I. Fight against armored targets. Toolkit. - M.: Military Publishing, 1977. 78 p. (P. 56).

5. Chebotarev I. Combat use of the Phantom aircraft / Foreign Military Review. 1976. No. 5. S.51-56.

6. PBA3.035.005 TO. Digital computing system 1A26M. Technical description. 116 p.

7. Product 9K35M2. Technical description and instruction manual. Part 1. 9K35M2TO. 51 sec

8. Control systems for aircraft (ballistic missiles and their warheads). Textbook for high schools. Razorenkov G.N., Bakhramov E.A., Titov Yu.F. / Ed. G.N. Razorenkova. - M.: Mechanical Engineering, 2003.584 s.

9. Product 9S80M. Technical description and instruction manual. BG2.399.056-01 TO4. 1991.182 s.

10. Shooting anti-aircraft artillery. Book one. M., Military Publishing, 1958. 398 p.

Names of figures

Figure 1 - Scheme for calculating the slant range at a set speed of the target

Figure 2 - Measurement of range to an air target at various angles

Figure 3 - Determination of the range of an air target at a set speed

Figure 4 - Graphic explanations to the conclusion of the formula for calculating the slant range

Claims (1)

A method for determining the oblique range of an air target by its set speed, including: observing a 2S6M anti-aircraft self-propelled gun by a gunner in an optical target of an air target, introducing an air target speed value into a digital computer system, controlling the handle of the joystick mechanism and thereby ensuring constant alignment of the aiming mark with the target silhouette , as well as the corresponding combination of the optical axis of the optical sight with the position of the air target using a tracking system controlled by signals knyuppelnogo mechanism eat angular coordinate values of the line of sight with the optical sight sensors and transmitting them to the digital computer system in successive times with intervals Δt, calculation of a digital computer system slant range D _i aerial target according to the formula

,
where ε _i - the value of sight elevation goal line in the i-th time; d _i - the horizontal range of the air target at the i-th point in time; D _i - the oblique range of the air target at the i-th point in time, characterized in that in the anti-aircraft self-propelled installation 2C6M additionally enter the equipment for receiving and implementing target designation, coupled with the transmission equipment of the target designation of the moving point reconnaissance and control, before calculating the oblique range between the anti-aircraft self-propelled device and an air target conduct reconnaissance of the air target with a mobile reconnaissance and control station, with the help of which its linear speed, called the set speed V _y , and the course angle Q _c are measured, transmit the indicated data to the anti-aircraft self-propelled gun using the targeting equipment of the mobile reconnaissance and control center, receive the target speed V _y and the heading angle Q _{c of the} air target using the equipment for receiving and implementing the target designation of the anti-aircraft self-propelled gun, and when calculating the oblique range D _{i of the} air target in i-th moment of time use the value of the horizontal range d _{i of the} air target at the i-th moment of time, calculated by the formula

,
where Δt is the time interval between consecutive adjacent measurements of the azimuthal positions of the line of sight of an air target; Δβ is the increment of the azimuth of the line of sight of the target for the time interval Δt between the i-th and (i-1) -m time points; β _i-1 - azimuth value of the line of sight of an air target at the (i-1) -th time moment; Q _c - the angle of the air target.

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