A SYSTEM AND METHOD FOR READING THE PULSE REPETITION FREQUENCY CODE IN LASER-GUIDED MUNITIONS.

Abstract

The invention relates to a PRF reading system and method that enables target detection and tracking of laser-guided munitions; it reads the Pulse Repetition Frequency (PRF) codes used by the laser designator via switches, encoding them securely and quickly using an oscillator and wave counter without requiring a microprocessor or software; and transmits these codes to avionics systems via a circuit board using the RS485 protocol.

Description

1 TARIFF IMPACT REPETITION FREQUENCY IN LASER-GUIDED MUNITIONS A system and method for reading the code. The technical field to which the invention relates: The invention enables target detection and tracking of laser-guided munitions; Laser 5 Pulse Repetition Frequency that the marker will use (PRF) codes are read via switches using oscillators and wave counters. code securely and quickly without requiring a microprocessor or software, and this code via a complete circuit board, using the RS485 protocol, to connect to avionics systems. It relates to a PRF reading system and method that enables its transfer. 10 The invention, in particular, allows switching between three or four key configurations, and data... Switching via RS485 transmitter with the ability to adjust transmission speed and frequency. By enabling continuous monitoring of their locations, the system status is provided in real time. This makes it possible to report to the avionics. State of the art: 15 Laser-guided munitions are short-range missiles guided to the target by a laser designator. pulses of duration (pulse width td: typically 10–30 ns) reflected from the target surface It detects and tracks targets by sensing the pulse. The temporal repetition of the pulses, the pulse The period is defined by T and the corresponding pulse repetition frequency (PRF); PRF typically ranges from 5–100 Hz and is 20 Hz to prevent military jamming. It is kept confidential. For coordination purposes between the launching platform and the marker. The PRF used is identified by a numerical “PRF Code”; the code is 3 or 4 digits long. It is expressed in a system (3 digits: 111–788, 4 digits: 1111–1788) and two The systems are compatible (missing 4th digit when using 3 digits). (default is accepted as “1”). In some cases, the code indicates that the ammunition is 25. while being transmitted digitally from the carrier; in other cases, ground personnel, ammunition It physically adjusts the code through the switches on it. Each switch has a power input (VCC) and 8 outputs indicating the switch position; The output corresponding to the current position is at the VCC level, the others are open circuit; 2 Therefore, which line is VCC is determined by reading all lines. Typical In applications, a piece of ammunition has both code and additional mission-related settings (impact mode, Additional keys can be added for ammunition type, roll angle, etc.; for example, three codes. For a structure containing a switch and a mode switch, VCC is provided to all switches. A total of 3× (8+1) + (4+1) =32 lines need to have their levels read. The current 5 In some designs, 36-line cabling is used for four switches; these lines are directly connected. Transmitted to the avionics readout unit or flexible print for space saving purposes. They are assembled into a single cabling using circuit boards (flex PCBs). Various proposals and applications for PRF reading methods in the known state of the art. Although improvements have been made, these improvements are still insufficient. Ten projects have been developed for this purpose. Some examples of applications for inventions are given below. Application file number “US6666142B1” is in the known state of the art. The invention in question has been examined. The invention in question is a laser-guided bomb with an impact mechanism. A simple but effective way to change the repetition frequency (PRF). It describes the design of the key / keying tool; the tool has a cylindrical body, a 15 a rectangular piece that attaches to the switch button at one end and the missing button at the other end In this case, it has a D-shaped opening that can be threaded onto the button shaft; black body two long white indicator lines on it (one when the button is in place, the other when the button is pressed) (When missing) it displays the current setting and ensures the new setting is applied correctly. And with the U-shaped handle, it can be attached to the user's seatbelt. 20 Application file number “JPS63263924A” is in the known state of the art. The invention in question has been examined. The invention in question is a hardware device used for data transmission. It describes a system for simplifying the circuit structure; here, an 8-bit by setting the least significant bit (LSB) of the shift register to logical “0” It is used as the start bit and is a logical 25 that does not have a clock pulse applied. The duration “1” functions as a stop bit. Parallel input data is stored in the register. is loaded, then generated with a specially designed OR gate arrangement. A series output signal is obtained using pulse signals. Application file number “US6611218B1” is in the known state of the art. It has been examined. The invention that is the subject of the application concerns the speed and 30 of modern communication systems. high speed designed to meet energy efficiency requirements 3 It relates to parallel-to-serial converters. The invention enables the conversion of parallel data bits with low power consumption. using current sources that are series-connected and differential current steering circuits It describes a data combination structure. These circuits respond to parallel data at the input. by generating incoming complementary current signals, the data is converted into differential and series formats. It converts. Additionally, in an application format, it uses complementary data transistors at the input. 5 This allows the circuit to respond more quickly to data changes. The current state of technology allows for the transmission of the PRF code using only 4 lines via RS485. performing digital data transfer via the standard, this transmission is carried out by the microcontroller, with a floating register and a single oscillator without using software or programmable hardware verification, also 3 and 4 key configurations via the same printed circuit board 10 It falls short in areas such as providing support and being able to automatically distinguish between different types of devices. In conclusion, due to the negative aspects described above and the current solutions, the subject matter... Due to its shortcomings, an improvement is needed in the relevant technical field. It has been made. Purpose of the invention: 15 The main purpose of the invention is to improve the cabling between code switches and the avionics system. Simplifying the system by reducing the number of lines used and making communication more reliable and lightweight. and to make it compact. This eliminates the need for more than 30 cables in traditional systems. The necessary connections can only be made via 4 lines, both in terms of weight and Significant advantages in terms of both volume and resistance to electromagnetic interference. 20 is obtained. Another objective of the invention is to digitize the PRF code using the RS485 electrical standard. The aim is to ensure that the code is transmitted securely over long distances. In this way, the code... The requirement for the keys to be located at the front of the ammunition is eliminated. Signal attenuation and electromagnetic 25 caused by increased cable lengths Entrepreneurial problems are minimized. Another objective of the invention is to increase the frequency and speed of data transmission on the printed circuit board. The aim is to enable adjustment by placing the specified resistors. In this way, the system It can be easily configured according to different usage needs, post-production. It is gaining flexibility. 30 4 Another objective of the invention is to control the transmission frequency and speed via a single oscillator. The aim is to enable adjustment. This eliminates the need for using multiple oscillators. Without compromising both circuit complexity and cost, the reliability of the system is improved. is being increased. Another objective of the invention is to enable both 3-digit and 4 / 5 digits to be displayed on the same printed circuit board. The aim is to enable the use of stepped code systems. This allows for a single card. Its design allows it to support two different systems: production and inventory management. It is becoming easier. Another purpose of the invention is to automatically adjust the number of keys (3 or 4) used in the system. The aim is to ensure that it can be perceived as such. In this way, the communication of the avionics system 10 Correct in both configurations without any changes to its structure or software. Data reading operations can be performed. The structural and characteristic features and all the advantages of the invention are given in the figures below. And thanks to the detailed explanation written with reference to these figures, it becomes clearer. This will be understood as such. Therefore, the evaluation should also include these forms and detailed explanations. 15 This should be done taking that into consideration. Explanation of the figures: FIGURE -1; Image of the representative position of the inventive keys on the ammunition. It is a drawing that gives. FIGURE 2; Mod 20, which allows setting and reading the PRF code. PRF reading complex with four key configurations that can be selected It is a drawing that gives the image. FIGURE 3; Image of the four-key card assembly and the detail of the housing on which it is mounted. It is a drawing that gives. FIGURE 4; Detailed view of the structure suitable for a three-key configuration. It is a drawing. FIGURE 5; Showing the general block diagram of the PRF reading card assembly. It is a drawing. FIGURE 6; This is a diagram showing an example of a wave counter. FIGURE 7; Detailed block diagram showing the PRF reading card assembly of the invention. It is a drawing. Explanation of the references in the figures: 1. First key 5 2. Second key 3. The third key 4. The fourth key 5. Four-key card set 6. Connector 10 7. The housing in which the four-key card assembly is mounted. 8. The housing in which the three-key card assembly is mounted. 10. Scrolling register 11. RS485 transmitter 12. Oscillator 15 13. Wave counter 14. Speed-selective resistors 15. Frequency selective resistors 19. Pull-down resistance 25. R6 20 26. R7 6 27. D1 entry 28. D0 entry Description of the invention: The invention enables target detection and tracking of laser-guided munitions; The pulse repetition frequency that the marker will use (Pulse Repetition Frequency 5) By reading the (PRF) codes via switches, the oscillator (12) and wave counter (13) using it allows you to code safely and quickly without requiring a microprocessor or software. via a complete circuit board, using the RS485 protocol, to connect to avionics systems. The housing (8) on which the three key card assembly is mounted, which enables the transfer or Switching between the configurations of the housing (7) in which the four key card assembly is mounted 10 RS485 transmitter with the ability to adjust data transmission speed and frequency. (11) By enabling continuous monitoring of key locations, the system status a PRF reading system that enables real-time reporting to the avionics and It is related to the method. The invention increases the number of lines used in the cabling between the code switches and the avionics system to 15. by reducing the system, simplifying communication, and making it more reliable, lightweight, and compact. It aims to eliminate the need for more than 30 cables in traditional systems. The necessary connections can only be made via 4 lines, both in terms of weight and significant advantages in terms of both volume and resistance to electromagnetic interference. is obtained. The invention is based on the PRF code 20 using the RS485 electrical standard. It enables the secure transmission of digital data over long distances. This method eliminates the need for the code keys to be located on the front of the ammunition. is decreasing; signal attenuation due to increased cable lengths and Electromagnetic interference problems are minimized. The invention also allows for the data transmission frequency and speed to be determined on the printed circuit board at 25 This allows the system to be adjusted by the placement of the resistors. Thus, the system can be used in different ways. It can be easily configured according to usage needs and post-production It gains flexibility. The transmission frequency and speed are controlled via a single oscillator (12). Thanks to its adjustability, the circuit can be configured without the need for multiple oscillators. Complexity and cost are reduced, and the reliability of the system is increased. Same print 30 7 Both 3-digit and 4-digit code systems can be processed via the circuit board. Its usability allows it to support two different systems with a single card design, facilitating production and inventory management. It simplifies management. Also, the number of keys used in the system (3 or 4) Thanks to its ability to be detected automatically, it is part of the communication structure of the avionics system. or in both configurations, the correct 5 without any changes to the software. Data reading operations can be performed. Laser-guided munitions launch from a target marked by a laser designator. By detecting reflected laser beams, they can identify and track targets, thus positioning themselves as being guided by the laser. It directs the laser beam onto the surface it is reflected onto. The laser beam comes in very short pulses. It is transmitted. The temporal distance between the centers of two pulses is called the "pulse period", 10 The frequency corresponding to this period is also called the "pulse repetition frequency". This is called Repetition Frequency (PRF). PRF is used because it is hidden. It uses a code called "PRF Code" to identify it. Some In these situations, this can be done with the help of special switches on the ammunition body. The code is programmed by ground personnel. The keys are located on the ammunition's 15 The representative location is shown in Figure 1. This code is typically used on the laser seeker. by itself or by an avionics within the munition, such as the missile computer It needs to be read electrically. The switches are connected to the relevant avionics via cables. It depends. The invention reduces the number of lines in the cabling between avionics and switches from 32 to 4, code 20. It transmits digitally at the RS485 level, controlling the transmission frequency and transmission speed. In adjusting, the microcontroller uses a single oscillator (12) for frequency and speed adjustment, It does not require the use of a microprocessor, CPLD, FPGA, or software; it's the same as a printed circuit board. The card supports the use of 3 and 4 keys and distinguishes between the use of 3 and 4 keys. It is able to do so. Mod 25 allows for the adjustment and reading of the PRF code. PRF reading complex with 4-key configuration that can be selected (Figure 2) This is indicated by . Four key card assembly (5) and the four key card assembly to which it is mounted The detail of the body (7) in which it is made is shown in Figure-3, and the detail of the structure suitable for the 3-key configuration. This is shown in Figure 4. The PRF adjustment switches are 1, 2, 3 and 4. It is being labeled. 8 The general block diagram of the PRF reading card assembly is shown in Figure 5. The position outputs of the switches (1, 2, 3, 4) are parallel to the sliding registers (10) (Shift Register). It depends on the data inputs. The clock signal from the oscillator (12) is fed into the wave counter (13) (Ripple (Counter) enters and is divided by wave counter (13). Wave counter (13) One of the high-speed clock signals (f2) at its output is used to determine the transmission speed. It is used. One of the relatively low-speed clock signals is the sliding (f3). to capture signals in parallel data inputs of registers (10) (Latch) It is used. The position information of the keys (1, 2, 3, 4) is transmitted via the RS485 transmitter (11). converted to electrical levels defined in the standard and read through connector (6) The information is transmitted to the avionics that will perform the action. 10 An example wave counter (13) is shown in Figure-6. Wave counter (13) has an input at its input. a circuit that performs counting in the binary system using a clock signal It is a component. In some cases, it is used as a frequency divider. In this system... Its purpose is to divide the frequency. The wave counter (13) QN shown in Figure-6. The clock frequency at the outputs specified is calculated according to the following formula: 15 fQN = f1 / 2(Q+1) f1 corresponds to the oscillator (12) frequency. Depending on the oscillator (12) frequency The frequencies that can be obtained for some Q values ​​are as follows: Oscillator Frequency (MHz) Q fQN (Hz) 1.8432 3 115200 1.8432 4 57600 1.8432 5 28800 1.8432 11 450 1.8432 12 225 1.8432 13 112.5 1.2288 4 38400 1.2288 5 19200 1.2288 6 9600 1.2288 11 300 1.2288 12 150 9 Oscillator Frequency (MHz) Q fQN (Hz) 1.2288 13 75 Table 1: Results Obtained for Some Q Values ​​Depending on Oscillator Frequency Frequencies The selection of the oscillator (12) frequency is made according to the communication speed to be used. During the production phase of the entire circuit board, the speed selector resistors shown in Figure 6 are used. (14) By arranging the appropriate one, one of the possible communication speeds can be selected. 5 The line with frequency f2 is connected to the CLK input of the sliding registers (10). Which they will scroll at speed and therefore what the RS485 transmitter (11) communication speed is It is determined that this will happen. How often will the sliding registers (10) capture the data in their parallel inputs? The F3 clock signal applied to LOAD inputs is used to determine this. 10 during the production phase. By arranging the appropriate frequency selector resistors (15) shown on Figure-6 Frequency selection is made. For example, an oscillator with a frequency of 1.8432MHz (12) It is used that the Q3 output of the wave counter (13) is connected to the CLK inputs of the sliding registers (10), Let's assume that the Q12 output is connected to the LOAD inputs. In this case, the sliding scale... Registers (10) will capture parallel data frequently at 225Hz, in other words switch 15 will detect changes in their positions and RS485 transmitter at 115200 baud (11) It will send a start bit in accordance with the UART protocol. It transmits eight data bits (Data Bit) and one stop bit (Stop Bit) and has five floating-point registers. (10) A total of 40 bits are transmitted. To prevent data packet corruption. f2 > 40 x f3 must be true. 20 The detailed block diagram of the PRF reading card assembly is given in Figure 7. RS485 The transmitter's (11) data input line pull-down resistor (19) helps to bring it to GND level. It is in a pulled state. The sliding register (10) is located closest to the RS485 transmitter (11). Input D0 (28) is also connected to level 3V3. This provides the system with initial power. When this is applied, the RS485 bus voltage is at a known level (LOW). Data transmission 25 When first started with input D0 (28), the RS485 bus level is set to HIGH. After receiving, the start bit is obtained thanks to the D1 input (27) at the GND level It is produced. When the CLK signal arrives, all bits are shifted and transmitted over the RS485 transmitter (11) is being sent. After the 40th hour strike, the sliding slope at the very beginning of the chain (10) Because the DIN input is at the 3V3 level, both the stop bit of the last byte is transmitted via RS485 transmitter (11) until the next LOAD operation. The level remains in the HIGH position. The sliding 5 at the very beginning of the chain. The slope (10) input D0 (28) can be adjusted to HIGH or LOW using resistors R6 (25) and R7 (26). It can be pulled down to this level. This input level is LOW in a 3-switch configuration. In order for this to be possible, R7 (26) is arranged, R6 (25) is not arranged. In the 4-key configuration, HIGH In order for this to be possible, R7 (26) is not arranged, R6 (25) is arranged. In this way, on the system 4. Whether the switch is inserted or not can be detected by the avionics system that reads the data. 10 The entrances D5, D6 and D7 of the sliding slope (10) at the very beginning of the chain should not be left empty. It is connected to the 3V3 level. Keys (First key (1), Second key (2), Third key (3), Fourth key (4)), physical keys that determine the PRF code; 3 or 4 keys on the card It is positioned to support the configuration. 15 The sliding registers (10), of which there are 5 in total, receive the switch status from the parallel inputs. These are registers that convert the bits into serial form and create a serial bit stream. Oscillator (12) (f₁), which is a single fundamental frequency that provides all clock signals of the system. It is a structure with a source frequency (e.g., 1.8432 MHz or 1.2288 MHz). The wave counter (13) produces clock outputs at different speeds by dividing the oscillator (12) signal (Qn 20 The outputs are structured as follows: One of the generated outputs is a high-speed serial output clock (f₂), and the other is... It is used as a low-speed latch clock (f₃) to capture parallel data. Speed ​​selector resistors (14) and Frequency selector resistors (15) (assembled during production), By selecting which Q outputs to use, the transmission speed (f₂) and capture frequency (f₃) can be determined. These are the resistances that enable them to make choices. 25 RS485 transmitter (11) transmits serial data electrically at RS485 level; to avionics It is a structure that connects via a connector. 11 Resistors R6 (25) and R7 (26) connect the D0 input (28) of the sliding register (10) at the head of the chain. Depending on the production configuration, the third switch / fourth switch is activated by pulling it to 3V3 or GND. These are resistors that provide the ability to distinguish the switching state. GND pull-down resistor (19) on RS485 data line, initially defined on the data line It is the structure that ensures it is in the (LOW) position. 5 Connector (6) is the structure that connects to the avionics via the RS485 line. Reading the pulse repetition frequency (PRF) code in laser-guided munitions. The method for this includes the following steps: Positioning the keys, - Personnel must physically set the PRF code using the keys (3 or 4 10 (key configuration). The card strengthens and returns to its initial state, - Pulling down the RS485 line to bring it to GND, The data bus and start bit are determined at the beginning of the chain for initial setup. Pulling the D0 entry of the sliding register to GND. 15 The oscillator (f₁) is activated. - A single oscillator operating to produce a stable frequency (e.g., 1.8432 MHz). Frequency division using a wave counter, - The wave counter takes f₁ and generates split clocks via the Qn outputs, - The selected Q outputs in production are f₂ (high-speed CLK for shifting) and f₃ (low-speed 20 Selecting LOAD / latch. (Example: f₁ = 1.8432 MHz, Q3 → 115200 Hz (f₂); Q12 → 225 Hz (f₃)). Parallel data capture (load / latch), 12 - Key changes for sampling at f3 speed: f₃ (LOAD) edge when it arrives, the parallel inputs (key positions) of the sliding registers being caught (latch). Serial shifting and transmission (with CLK), - The registers are shifted serially with f₂ (CLK) pulses and all bits are 5 The data is then sent sequentially to the RS485 transmitter's data input. Since that card has 5 sliding registers, the total number of bits transmitted is: 5 × 8 = 40-bit (in the example configuration). Framing is applied in UART format: 1 start bit + 8 data bits + 1 stop bit (per byte). Performing RS485 leveling and generating the start bit, 10 - When transmission is first initiated with D0, the RS485 line should be in the HIGH position, and then... The start bit is generated thanks to D1 at the GND level. Line idle behavior during transmission, - After the 40th CLK pulse, since the DIN at the beginning of the chain is 3V3, the last byte... A stop bit is sent and the RS485 line remains HIGH 15 until the next LOAD operation. remains in that state. Detecting the 3-vs-4 key configuration, - Due to the R6 / R7 configuration, a specific D0 level at the beginning of the chain The configuration is read by the avionics; so the avionics is 3 keys or... It can tell if 4 keys were used. 20 Periodic repetition is required. Parallel data is captured at a frequency determined by the period f₃ (e.g., 225 Hz) and serially transmitted using f₂. It is sent via RS485. This cycle continues continuously / repeatedly.

Claims

13 REQUESTS 1. Reading the pulse repetition frequency code in laser-guided munitions. It is a system for, and its characteristic is; - The first key (1), which is the physical key that determines the PRF code, second The four 5 keys are the first key (2), the third key (3) and the fourth key (4). key card set (5) or card set with three keys The housing (8) or four on which three key card assemblies are mounted configuration of the housing (7) where the key card assembly is mounted switches positioned to provide support, - It converts the key state from parallel inputs to serial format and is serial 10 The five sliding registers (10) that make up the bit stream, - One frequency source that provides all the clock signals for the system. oscillator (12), - By splitting the oscillator (12) signal, outputs with clock lines at different speeds wave counter (13), 15 - By selecting which outputs to use, you can control transmission and reception speed. speed-selective resistors are assembled during the manufacturing process to enable frequency selection. (14) and frequency selective resistors (15), - Transmitting serial data electrically and to the avionics via connector (6) connected RS485 transmitter (11), 20  According to the production configuration of the sliding register (10) at the chain head the possibility of distinguishing between the third key or the fourth key status resistors for initial level regulation, - On the RS485 data line, the data line must be in the initially defined position. GND pull-down resistor (19), 25 - Connection point to the avionics via the RS485 transmitter (11) line It contains connector (6).

2. Pulse repetition frequency in laser-guided munitions conforming to Claim 1. It is a system for reading code, and its features include a high-speed serial output clock. One of them is a 30 that produces outputs with a low-speed latch clock to capture parallel data. It contains a wave counter (13). 14 3. Reading the pulse repetition frequency code in laser-guided munitions. It is a method for, and its characteristic is;  Positioning of the switches,  The card strengthens and returns to its initial state,  The oscillator starts operating, 5  Frequency division using a wave counter,  Parallel data capture,  Performing serial shifting and transmission,  Leveling and generating the start bit of the RS485 transmitter,  Identifying three or four key configurations is process 10 It includes the steps.

4. Pulse repetition frequency in laser-guided munitions conforming to Claim 3. It is a method for reading the code, and its feature is; Keys positioning process step;  Personnel's PRF code, physically with keys, 3 or 4 keys 15 The configuration setup process involves adjusting the settings.

5. Pulse repetition frequency in laser-guided munitions conforming to Claim 3. It is a method for reading the code, and its feature is; strengthening and starting the card. the process step to reach this state;  The data path and start bit must be determined at the beginning of the chain (20). pull down the GND of the RS485 data line on the sliding register at the beginning. The process involves pulling the price down through resistance.

6. Pulse repetition frequency in laser-guided munitions conforming to Claim 3. It is a method for reading the code, and its feature is; activating the oscillator. process step; 25  The process step of a single oscillator operating and producing a constant frequency It includes.

7. Pulse repetition frequency in laser-guided munitions conforming to Claim 3. It is a method for reading the code, and its feature is; frequency with wave counter. The division process step; 30  The wave counter receives the constant frequency produced by the oscillator and outputs it. It involves the process of generating divided hours.

8. Pulse repetition frequency in laser-guided munitions conforming to Claim 3. It is a method for reading the code, and its feature is; Parallel data capture. The process step to be performed is; 5  To collect samples at a rate that captures key changes frequently. The key positions of the sliding registers when the load edge arrives. This involves the process step of capturing parallel inputs.

9. Pulse repetition frequency code for laser-guided munitions conforming to Claim 3. It is a method for reading, and its feature is; Serial shifting and transmission process 10 step;  Serial shifting of sliding registers with transmission rate pulses and The process involves sending all bits sequentially to the data input of the RS485 transmitter. It includes the step.

10. The pulse repetition frequency for laser-guided munitions conforming to Claim 3 is 15. It is a method for reading the code, and its characteristic is that it is an RS485 transmitter code. The process step involves leveling and generating the initial bit;  When transmission is initiated with the first D0, the RS485 transmitter line is placed in a high position. and then the starting bit thanks to D1 at the GND level of the next bit Its formation involves the process step. 20 11. Pulse repetition frequency in laser-guided munitions conforming to Claim 3. It is a method for reading the code, and its characteristic is; three or four keys. The process step involves determining the configuration;  Production to detect the use of three or four avionics switches with the configuration of the selective resistors arranged in the stage, the 25 at the beginning of the chain Specific D0 level regulation is read by the avionics process. It includes the step.

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