Processing method for improving channel transmission safety performance of identification friend or foe system

Abstract

The invention relates to a processing method for improving channel transmission safety performance of an identification friend or foe system, and belongs to the technical field of communication data processing. According to the method, the interrogator or the responder can judge whether the received signal is a forwarding signal or a reflection signal when working, so that the interference of a false interrogation signal or a false response signal is eliminated, the defect that a traditional identification friend or foe system is easily interfered when working is eliminated, and the anti-interference performance of the identification friend or foe system is improved. In the method, the synchronization head of the inquiry signal waveform frame or the response signal waveform frame is randomly disturbed, the time data is introduced into the random disturbance, and the final offset value of the synchronization head is generated by adopting a specific random sequence, so that the accuracy of the synchronization head is improved. The enemy is difficult to decode or snoop the change rule of the position of the synchronous head and cannot further extract the data bit closely following the synchronous head, so that the security and confidentiality are higher.

Description

Technical Field

[0001] The invention belongs to the technical field of communication data processing, and in particular relates to a processing method for improving the transmission security performance of a friend-or-foe identification system channel. Background Art

[0002] IFF technology originated in the 1940s, and the IFF equipment developed based on this technology was used in large quantities in the military in the 1960s. After being tested in many local wars, IFF equipment has become an indispensable part of the active combat system of various military powers. IFF equipment includes interrogators, transponders, cipher machines, and key management subsystems (including key generation and management centers, key distribution management terminals, and key loaders). These equipment constitute a fully functional IFF system. Among them, interrogators and transponders are equipped on each combat platform respectively, and are equipped with cipher machines for collaborative work. The key management subsystem provides the required keys for the cipher machine to encrypt or decrypt data. On the battlefield, when the combat platform attacks the target, the interrogator equipped with the platform generates an encrypted interrogation signal, and the transponder equipped on the target platform decrypts after receiving the interrogation signal and generates a corresponding encrypted response signal. The interrogator decrypts after receiving the response signal and verifies its identity based on the decrypted plaintext. The collaborative working mode of the interrogator and transponder can provide the judgment of the enemy identity at the moment of attack, which greatly reduces the probability of friendly targets being accidentally injured. However, with the rapid development of battlefield electronic countermeasure technology, the security performance of early traditional friend-or-foe identification systems has become increasingly fragile, exposing many deficiencies in modern warfare and is far from meeting the needs of modern warfare.

[0003] In the traditional IFF system, when the interrogator and transponder work together, affected by the geographical environment, the signal will be reflected multiple times and travel through multiple paths to reach the other party. The reflected signal is the same as the original signal, and the IFF equipment cannot distinguish and will receive and process it. For the interrogator, receiving and processing the reply reflection signal will solve the wrong target direction and distance; for the transponder, when the number of received and processed interrogation reflection signals is too large, it will have no time to process the normal interrogation signal, causing a sharp drop in the working efficiency of the transponder.

[0004] In the traditional friend-or-foe identification system, the waveform frames of the interrogation signal generated by the interrogator and the response signal generated by the transponder are fixed, and their security only comes from the encrypted data part in the waveform frame, which makes it possible for the enemy to interfere with our friend-or-foe identification equipment. First, on the battlefield, the enemy cannot crack its ciphertext data by relying solely on a small amount of intercepted electromagnetic wave signals. By repeatedly forwarding friendly interrogation signals and deceiving the transponders equipped on friendly combat platforms to produce several responses, the enemy will obtain enough samples. By traversing and analyzing these massive sample data, the enemy can obtain the inherent rules of friendly data encryption, which provides the possibility for the enemy to decipher the ciphertext data. Secondly, if the enemy forwards interrogation signals uninterruptedly and at a high frequency in a short period of time, inducing the transponder to continuously produce response signals and having no time to respond to the normal interrogation signals of the friendly party, this saturation attack will make the friendly transponder unable to work normally and its working efficiency will drop sharply. Finally, on the battlefield, after intercepting the friendly response signal, the enemy can forward the response signal to the friendly interrogator again, causing the friendly party to mistakenly identify the enemy target as a friendly party, which provides the possibility for the enemy to break through its air defense area. This deception method brings great risks to combat, and its consequences are unpredictable and immeasurable.

[0005] The interrogation signal generated by the traditional IFF interrogator includes 4 synchronization pulses and 32 position pulses. The positions between the pulse fronts (rising edges) are fixed. The first 4 synchronization pulses have the same spacing, and the spacing between adjacent pulse fronts is 2us. The first 4 synchronization pulses are followed by 32 position pulses, and the first position pulse front is 10us away from the first synchronization pulse front. The 32 position pulses have the same spacing, and the spacing between adjacent pulse fronts is 2us. For such an interrogation signal with a fixed waveform frame, the signal after multiple reflections or the signal forwarded by the enemy is exactly the same as the original signal, and the characteristic parameters that distinguish the two cannot be extracted, thereby failing to achieve the purpose of suppressing the reflected signal or forwarding the signal. The response signal waveform generated by the traditional IFF transponder includes three pulses, which only realize the identification of the enemy and the friend. The spacing between the adjacent pulse fronts (rising edges) is fixed to 1.75us. For such a response signal with a fixed waveform frame, the signal after multiple reflections or the signal forwarded by the enemy is exactly the same as the original signal, and the characteristic parameters that distinguish the two cannot be extracted, thereby failing to achieve the purpose of suppressing the reflected signal or forwarding the signal.

[0006] Therefore, at this stage, it is necessary to design a processing method to improve the channel transmission security performance of the friend-or-foe identification system to solve the above problems. Summary of the invention

[0007] The purpose of the present invention is to provide a processing method for improving the channel transmission security performance of an IFF system, so as to solve the technical problems existing in the above-mentioned prior art.

[0008] To achieve the above object, the technical solution of the present invention is:

[0009] A processing method for improving the transmission security performance of a friend-or-foe identification system channel comprises the following steps:

[0010] Step 1: The key management subsystem generates relative reference time data and distributes it to the key loader, which loads the reference time data into the cipher machines located on the interrogator and transponder;

[0011] Step 2: The cipher machine uses the reference time data to generate the time reference factor T R , and using the time reference factor T R As the initial value, the perturbation factor S for the interrogation signal is generated using a pseudo-random generation sequence. I , the disturbance factor S used for the identification response signal F , the disturbance factor S used for the intelligence data reply signal R ; and transmitted to the interrogator or transponder;

[0012] Step 3: The interrogator receives the time reference factor T from its matching cipher machine. R and the interrogation signal disturbance factor S I , generating an interrogation signal of waveform frame change;

[0013] Step 4: The answering machine receives the time reference factor T from the cipher machine that matches it. R and the interrogation signal disturbance factor S I , calculate the disturbance value of the corresponding synchronization head, calculate the expected position of the synchronization head, and compare it with the synchronization head position value of the received inquiry signal to determine its validity. If it is invalid, no response signal is generated to shield the interfering false inquiry signal; if it is valid, then perform subsequent processing;

[0014] Step 5: If the interrogation signal is valid and legal, the transponder receives the time reference factor T from the cipher machine that matches it according to the interrogation signal type. R , the disturbance factor S of the identity recognition response signal F and the disturbance factor S used to provide the intelligence data reply signal R , generates a response signal with a waveform frame change. If identity recognition is required, the identity recognition response signal disturbance factor S is used F Generate a response signal with a waveform frame change. If you want to obtain intelligence information, you need to use the time reference factor T R and the disturbance factor S of the intelligence data reply signal R Generates a response signal of waveform frame change;

[0015] Step 6: For both types of response signals, the interrogator receives the time reference factor T from the cipher machine that matches it. R , the disturbance factor S of the identity recognition response signal F and the disturbance factor S of the reply signal used to provide intelligence data R , calculate the disturbance value of the corresponding synchronization head, and compare it with the received response signal synchronization head disturbance value to determine its validity. If it is invalid, no response signal is generated and the interfering false response signal is shielded; if it is valid, subsequent processing is performed.

[0016] Furthermore, step 1 includes:

[0017] Step 11: The key generation and management center generates relative reference time data including year, month, day, hour, minute and second;

[0018] Step 12: The key generation and management center distributes the generated reference clock data and key data together to the key distribution management terminal of the theater or combat unit through a wired network or encrypted storage medium;

[0019] Step 13: The key loader obtains the reference clock data and key data from the key distribution management terminal and loads them to the cipher machine located on the interrogator or transponder. The cipher machine uses the reference clock data to generate a 14-bit binary sequence of time reference factor T R , and use the time reference factor to generate the disturbance factor S.

[0020] Furthermore, step 2 includes:

[0021] Step 21: The cipher machine uses the reference time data to correct its own time, and keeps the time of the cipher machine synchronized with the time of the current key management subsystem;

[0022] Step 23: The cipher generates a reference time factor T using the currently received time data R ;

[0023] Step 24: Generate a 7-bit binary pseudo-random sequence of the interrogation signal using a pseudo-random generation method, and use the reference time factor T R Limit the timing of extracting the 7-bit binary pseudo-random sequence. The final sequence obtained is the disturbance factor S I ;

[0024] Step 25: Generate a 4-bit binary pseudo-random sequence for the identity recognition response signal using a pseudo-random generation method, and use the reference time factor T R The timing of extracting the 4-bit binary pseudo-random sequence is limited. The final sequence obtained is the 4-bit binary perturbation factor S used to identify the enemy attribute response signal. F ;

[0025] Step 26: Generate a 7-bit binary pseudo-random sequence for providing a response signal for obtaining intelligence data using a pseudo-random sequence, and use the reference time factor T R The timing of extracting the 7-bit binary pseudo-random sequence is limited. The final sequence obtained is the disturbance factor S of the 7-bit binary sequence used for situational awareness or obtaining intelligence data. R .

[0026] Furthermore, step 3 includes:

[0027] Step 31: Using the current time base factor T R and the interrogation signal disturbance factor S I The disturbance value S that generates the first synchronization header IP1 , its disturbance value S IP1 The specific algorithm process for obtaining is:

[0028] If T R mod 3=0, then S IP1 =(int(S I / 16))mod 8;

[0029] If T R mod 3=1, then S IP1 =(int(S I / 16))mod 8+8;

[0030] If T R mod 3=2, then S IP1 =(int(S I / 16))mod 8+16;

[0031] Finally, the disturbance value is used to generate the time domain position of the first synchronization head. The time interval between the falling edge of the synchronization head pulse and the falling edge of the fourth pulse is:

[0032] Natural position + disturbance position = 40.375us + S IP1 ×2×0.0625us;

[0033] Step 32: Using the current time base factor T R and the interrogation signal disturbance factor S I Generate the disturbance value S of the second synchronization head IP2 , its disturbance value S IP2 The specific algorithm process for obtaining is:

[0034] If T R mod 3=0, then S IP2 =(int(S I / 4))mod 4+16;

[0035] If TR mod 3=1, then S IP2 =(int(S I / 4))mod 4;

[0036] If T R mod 3=2, then S IP2 =(int(S I / 4))mod 4+20;

[0037] Finally, the disturbance value is used to generate the time domain position of the second synchronization head. The time interval between the falling edge of the synchronization head pulse and the falling edge of the fourth pulse is:

[0038] Intrinsic position + disturbance position = 23us + S IP2 ×2×0.0625us;

[0039] Step 33: Using the current time base factor T R and the interrogation signal disturbance factor S I The disturbance value S that generates the third synchronization header IP3 , its disturbance value S P3 The specific algorithm process for obtaining is:

[0040] If T R mod 3=0, then S IP3 =S I mod 4+8;

[0041] If T R mod 3=1, then S IP3 =S I mod 4+4;

[0042] If T R mod 3=2, then S IP3 =S I mod 4;

[0043] Finally, the disturbance value is used to generate the time domain position of the third synchronization head. The time interval between the falling edge of the synchronization head pulse and the falling edge of the fourth pulse is:

[0044] Intrinsic position + disturbance position = 13us + S IP3 ×2×0.0625us.

[0045] Furthermore, step 4 includes:

[0046] Step 41: The answering machine receives the time reference factor T from the cipher machine that matches it. R and the interrogation signal disturbance factor S I , and save it from the current T RThe data of three consecutive times up to now, namely T R , T R -1, T R -2 and the corresponding S I , S I1 , S I2 ;

[0047] Step 42: Utilizing the Stored T R , T R -1, T R -2 and corresponding S I , S I1 , S I2 Data, using the algorithm of step 31, calculate the expected position of the first synchronization head pulse, and then compare it with the corresponding pulse position extracted from the received interrogation signal. If the error is within ±15.625ns, it will be processed later; if the error exceeds ±15.625ns, it will not be received;

[0048] Step 43: Utilizing the Stored T R , T R -1, T R -2 and corresponding S I , S I1 , S I2 The data is then processed by using the algorithm in step 32 to calculate the position of the second synchronization head pulse, and then compared with the corresponding pulse position extracted from the received interrogation signal. If the error is within ±15.625ns, the data is processed; if the error exceeds ±15.625ns, the data is not received.

[0049] Step 44: Utilizing the Stored T R , T R -1, T R -2 and corresponding S I , S I1 , S I2 Data, use the algorithm of step 33 to calculate the expected position of the third synchronization head pulse, and then compare it with the corresponding pulse position extracted from the received interrogation signal. If the error is within ±15.625ns, subsequent processing is performed; if the error exceeds ±15.625ns, it will not be received.

[0050] Furthermore, step 5 includes:

[0051] Step 51: If obtaining intelligence information, the current time reference factor T is required R and the disturbance factor S of the intelligence data reply signal R Generate the disturbance value S of the first synchronization header in the intelligence response data RP1 , its disturbance value S RP1The specific algorithm process for obtaining is:

[0052] If T R mod 3=0, then S RP1 =(int(S R / 16))mod 8;

[0053] If T R mod 3=1, then S RP1 =(int(S R / 16))mod 8+8;

[0054] If T R mod 3=2, then S RP1 =(int(S R / 16))mod 8+16;

[0055] Finally, the disturbance value is used to generate the time domain position of the first synchronization head. The time interval between the falling edge of the synchronization head pulse and the falling edge of the fourth pulse is:

[0056] Intrinsic position + disturbance position = 26.625us + S RP1 ×2×0.0625us;

[0057] Step 52: If obtaining intelligence information, the current time reference factor T is required R and the disturbance factor S of the intelligence data reply signal R The disturbance value S of the second synchronization header in the generated intelligence response data RP2 , its disturbance value S RP2 The specific algorithm process for obtaining is:

[0058] If T R mod 3=0, then S RP2 =(int(S R / 4))mod 4+16;

[0059] If T R mod 3=1, then S RP2 =(int(S R / 4))mod 4;

[0060] If T R mod 3=2, then S RP2 =(int(S R / 4))mod 4+20;

[0061] Finally, the disturbance value is used to generate the time domain position of the second synchronization head. The time interval between the falling edge of the synchronization head pulse and the falling edge of the fourth pulse is:

[0062] Intrinsic position + disturbance position = 17.25us + S RP2 ×2×0.0625us;

[0063] Step 53: If obtaining intelligence information, the current time reference factor T is required R and the disturbance factor S of the intelligence data reply signal R The disturbance value S of the third synchronization header in the generated intelligence response data RP3 , its disturbance value S RP3 The specific algorithm process for obtaining is:

[0064] If T R mod 3=0, then S RP3 =S R mod 4+8;

[0065] If T R mod 3=1, then S RP3 =S R mod 4+4;

[0066] If T R mod 3=2, then S RP3 =S R mod 4;

[0067] Finally, the disturbance value is used to generate the time domain position of the third synchronization head. The time interval between the falling edge of the synchronization head pulse and the falling edge of the fourth pulse is:

[0068] Intrinsic position + disturbance position = 5.0us + S RP3 ×2×0.0625us;

[0069] Step 54: If identity recognition is required, the disturbance value S of the first synchronization header in the identity recognition response signal FP1 and the identity recognition response signal disturbance factor S F The same; the disturbance value is used to generate the time domain position of the first synchronization head. The time interval between the falling edge of the synchronization head pulse and the falling edge of the second pulse is:

[0070] Intrinsic position + disturbance position = 3.0us + S F ×2×0.0625us.

[0071] Furthermore, step 6 includes:

[0072] Step 61: The interrogator receives the time reference factor T from its matching cipher machine. R , the disturbance factor S of the identity recognition response signal F and the disturbance factor S of the reply signal used to provide intelligence data R , and save it from the current TR The data of three consecutive times up to now, namely T R , T R -1, T R -2 and the corresponding S F , S F1 , S F2 With S R , S R1 , S R2 ;

[0073] Step 62: After receiving the response signal, if the interrogator obtains intelligence information, it uses the stored T R , T R -1, T R -2 and corresponding S R , S R1 , S R2 Data, using the algorithm of step 51, calculate the position of the first synchronization head pulse, and then compare it with the corresponding pulse position extracted from the received response signal. If the error is within ±15.625ns, perform subsequent processing; if the error exceeds ±15.625ns, do not receive it;

[0074] Step 63: After receiving the response signal, if the interrogator obtains intelligence information, it uses the stored T R , T R -1, T R -2 and corresponding S R , S R1 , S R2 The data is received, and the algorithm of step 52 is used to calculate the position of the second synchronization head pulse, and then the position is compared with the corresponding pulse position extracted from the received response signal. If the error is within ±15.625ns, subsequent processing is performed; if the error exceeds ±15.625ns, it is not received;

[0075] Step 64: After receiving the response signal, if the interrogator obtains intelligence information, it uses the stored T R , T R -1, T R -2 and corresponding S R , S R1 , S R2 The data is received, and the algorithm of step 53 is used to calculate the position of the third synchronization head pulse, and then it is compared with the corresponding pulse position extracted from the received response signal. If the error is within ±15.625ns, subsequent processing is performed; if the error exceeds ±15.625ns, it is not received;

[0076] Step 64: After the interrogator receives the response signal, if it is identity recognition response data, it uses the stored TR , T R -1, T R -2 and corresponding S F , S F1 , S F2 Data, using the algorithm of step 54, calculate the expected position of the first synchronization head pulse, and then compare it with the corresponding pulse position extracted from the received response signal. If the error is within ±15.625ns, subsequent processing is performed; if the error exceeds ±15.625ns, it is not received.

[0077] Compared with the prior art, the present invention has the following beneficial effects:

[0078] The present invention proposes a processing method for improving the channel transmission security performance of the friend-or-foe identification system, which enables the interrogator or transponder to determine whether the received signal is a forwarded or reflected signal when working, thereby eliminating the interference of false interrogation signals or false response signals. The application of this method eliminates the defect that makes the traditional friend-or-foe identification system susceptible to interference when working, and improves the anti-interference performance of the friend-or-foe identification system.

[0079] The present invention proposes a processing method for improving the transmission security performance of a friend-or-foe identification system channel, which improves the security and confidentiality of the channel. In this method, the synchronization header of an inquiry signal waveform frame or a response signal waveform frame is randomly disturbed. This random disturbance introduces time data, and uses a specific random sequence to generate the final offset value of the synchronization header. It is difficult for the enemy to decipher or spy on the changing pattern of the synchronization header position, and it is impossible to further extract the data bits immediately following the synchronization header, so the security and confidentiality are higher.

[0080] The processing method for improving the transmission security performance of the IFF system channel proposed by the present invention can be used in conjunction with other anti-interference methods in the IFF system to further improve the anti-interference capability of the IFF system. The method proposed by the present invention and other anti-interference methods have been used in IFF system equipment, and the good performance of this method has been further verified. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Figure 1 The present invention is a flow chart for controlling the generation of time data for time reference factors and disturbance factors in a friend-or-foe identification system.

[0082] Figure 2 It is a schematic diagram of the synchronization pulse of the inquiry-response signal before and after the improvement in the present invention.

[0083] Figure 3 is the reference time factor T in the present invention R Generate an algorithm implementation flowchart.

[0084] Figure 4is the interrogation signal disturbance factor S in the present invention I Generate an algorithm implementation flowchart.

[0085] Figure 5 is the identity recognition response signal disturbance factor S in the present invention F Generate an algorithm implementation flowchart.

[0086] Figure 6 is the disturbance factor S of the state intelligence response signal in the present invention R Generate an algorithm implementation flowchart.

[0087] Figure 7 This is a flowchart of the algorithm for generating the first synchronization head position of the inquiry signal in step 1401 of the present invention.

[0088] Figure 8 This is a flow chart of the algorithm for generating the second synchronization head position of the inquiry signal in step 1402 of the present invention.

[0089] Fig. 9 This is a flow chart of the algorithm for generating the third synchronization head position of the inquiry signal in step 1403 of the present invention.

[0090] Fig.10 This is a flow chart of the algorithm for generating the first synchronization head position of the intelligence response signal in step 1501 of the present invention.

[0091] Fig.11 This is a flow chart of the algorithm for generating the second synchronization head position of the intelligence response signal in step 1502 of the present invention.

[0092] Fig.12 This is a flowchart of the algorithm for generating the third synchronization head position of the intelligence response signal in step 1503 of the present invention.

[0093] Fig.13 This is a flowchart of the algorithm for generating the first synchronization head position of the identity recognition response signal in step 1601 of the present invention.

[0094] Fig.14 It is a flow chart for implementing the determination of validity of the synchronization head of the inquiry signal in the present invention.

[0095] Fig.15 It is a flow chart for implementing the validity determination of the synchronization head of the intelligence response signal in the present invention.

[0096] Fig.16 It is a flow chart for implementing the validity determination of the synchronization head of the identity recognition response signal in the present invention. DETAILED DESCRIPTION

[0097] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0098] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative work are within the scope of protection of the present invention. It should be noted that relational terms such as the terms "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0099] Moreover, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a list of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus. In the absence of more restrictions, an element defined by the phrase "comprises a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus that includes the element.

[0100] A processing method to improve the channel transmission security performance of the friend-or-foe identification system is proposed, which needs to be implemented by the following specific steps:

[0101] Step 1: The key management subsystem generates relative reference time data and distributes it to the key loader, which loads the data into the cipher machines located on the interrogator and transponder.

[0102] Step 2: The cipher machine uses the reference time data to generate the time reference factor T R , and using the time reference factor T R As the initial value, the perturbation factor S for the interrogation signal is generated using a pseudo-random generation sequence. I , the disturbance factor S used for the identity recognition (including friend or foe attributes) response signal F , the disturbance factor S used for the intelligence data (situational awareness) response signal R and transmitted to the interrogator or transponder.

[0103] Step 3: The interrogator receives the time reference factor T from its matching cipher machine. R and the interrogation signal disturbance factor S I , generating an interrogation signal with a waveform frame change.

[0104] Step 4: The answering machine receives the time reference factor T from the cipher machine that matches it. R and the interrogation signal disturbance factor S I , calculate the disturbance value of the corresponding synchronization head, further calculate the expected position of the synchronization head, and compare it with the synchronization head position value of the received inquiry signal to determine its validity. If it is invalid, no response signal is generated, and the interfering false inquiry signal is shielded; if it is valid, subsequent processing is performed.

[0105] Step 5: If the interrogation signal is valid and legal (the present invention does not involve the determination and processing method of legality), the transponder receives the time reference factor T from the cipher machine matched with it according to the type of interrogation signal. R , the disturbance factor S of the identity recognition response signal F and the disturbance factor S used to provide the intelligence data reply signal R , generates a response signal with a waveform frame change. If identity recognition is required, the identity recognition response signal disturbance factor S is used F Generate a response signal with a waveform frame change (including enemy and friend attributes). If you want to obtain intelligence information, you need to use the time reference factor T R and the disturbance factor S of the intelligence data reply signal R Generates a response signal with a waveform frame change (combat platform code, longitude, latitude, altitude, etc.).

[0106] Step 6: For both types of response signals, the interrogator receives the time reference factor T from the cipher machine that matches it. R , the disturbance factor S of the identity recognition response signal F and the disturbance factor S of the reply signal used to provide intelligence data R , calculate the disturbance value of the corresponding synchronization head, and compare it with the received response signal synchronization head disturbance value to determine its validity. If it is invalid, no response signal is generated, shielding the interfering false response signal; if it is valid, perform subsequent processing.

[0107] Furthermore, the step 1 specifically includes:

[0108] Step 11: The key generation and management center generates relative reference time data containing year, month, day, hour, minute, and second (accurate to 0.01 second). This time can be used to extract the absolute time of the system, or it can be manually set according to operational requirements. The manually set reference time has stronger confidentiality and security.

[0109] Step 12: The key generation and management center distributes the generated reference clock data and key data together to the key distribution management terminal of the theater or combat unit through a wired network or encrypted storage medium.

[0110] Step 13: The key loader obtains the reference clock data and key data from the key distribution management terminal and loads them to the cipher machine located on the interrogator or transponder. In order to realize the system's anti-interference and forwarding interference function, the cipher machine needs to use the reference clock data to generate a 14-bit binary sequence of time reference factor T R , and use the time reference factor to generate the disturbance factor S.

[0111] Furthermore, the step 2 specifically includes:

[0112] Step 21: The cipher machine uses the reference time data to correct its own time and keep the cipher machine time synchronized with the current key management subsystem time.

[0113] Step 23: The cipher generates a reference time factor T using the currently received time data R The principle is to convert 24 hours / day into seconds, that is: 24×60×60=86400 seconds, with 8 seconds (the setting of this value needs to take into account the time it takes for the cipher machine to transmit data to the interrogator or transponder, the time it takes for the interrogator to generate an interrogation signal, the time it takes for the transponder to receive and process the interrogation signal, the time it takes for the transponder to generate a response signal, the time it takes for the interrogator to receive and process the response signal, the propagation time of the 1030MHz carrier interrogation signal between the interrogator and the transponder, and the propagation time of the 1090MHz carrier response signal between the transponder and the interrogator) as a time period, and 86400 seconds can be divided into 10800 time periods. The cipher machine uses the received time data as the reference for timing. If the current time is an integer multiple of 8 seconds, its value is converted to T R For example, if the current time is 15:14:16, then 15×60×60+14×60+16=54856 seconds, T R =54856÷8+1=6858. Then every 8 seconds, T is output. R In short, the benchmark time factor T R It is calculated from the reference time data, and the reference time data can be set by yourself. Therefore, the reference time factor T R It has a certain randomness.

[0114] Step 24: Generate a 7-bit binary pseudo-random sequence of the interrogation signal using a pseudo-random generation method, and use the reference time factor T R Limit the timing of extracting the 7-bit binary pseudo-random sequence. The final sequence obtained is the disturbance factor S I(The corresponding maximum decimal value is 127). Since the balance, run distribution, and autocorrelation characteristics of the M sequence are extremely similar to those of a random sequence, and the number of sequences it contains is larger, the pseudo-random sequence generation algorithm uses the characteristic polynomial x 7 +x 3 +1 M sequence generation method, the specific generation process is: set the initial value of the 7-bit M sequence generator to a6a5a4a3a2a1a0=1001000 (the user can set different initial values, and the initial values ​​of the cipher machine equipped with any platform interrogator or transponder to run the algorithm must be exactly the same); complete the operation of the nonlinear feedback shift register under the triggering of the clock signal or periodic signal, that is, perform the assignment operation a' 0＝ a1、a' 1＝ a2、a' 2＝ a3、a' 3＝ a4, "'

[0115] a 4＝ a5、a 5＝ a6、a Completion and reference time factor T R When the same number of shift operations are performed (in order to improve its randomness, the reference time factor T calculated by using time data such as year, month, day, minute, second, etc. or several of them can also be used R To control the number of shift operations), the value of a'6a'5a'4a'3a'2a'1a'0 is the perturbation factor S of the 7-bit binary sequence. I . Due to S I T R Control, while T R The cycle of value output is 8 seconds, so S I The value output cycle is 8 seconds.

[0116] Step 25: Generate a 4-bit binary pseudo-random sequence for the identity recognition response signal using a pseudo-random generation method, and use the reference time factor T R The timing of extracting the 4-bit binary pseudo-random sequence is limited. The final sequence obtained is the 4-bit binary perturbation factor S used to identify the enemy attribute response signal. F Since the balance, run distribution, and autocorrelation characteristics of the M sequence are extremely similar to those of a random sequence, and the number of sequences it contains is larger, the pseudo-random sequence generation algorithm uses the characteristic polynomial x 4+x+1 M sequence generation method, the specific generation process is: set the initial value of the 4-bit M sequence generator to a3a2a1a0=1001 (the user can set different initial values, and the initial values ​​of the cipher machine equipped with any platform interrogator or transponder to run the algorithm must be exactly the same); complete the operation of the nonlinear feedback shift register under the triggering of the clock signal or periodic signal, that is, perform the assignment operation a' 0＝ a1、a' 1＝ a2、a' 2＝ a3. Completion and reference time factor T R When the same number of shift operations are performed (in order to improve its randomness, the reference time factor T calculated by using time data such as year, month, day, minute, second, etc. or several of them can also be used R To control the number of shift operations), the value of a'3a'2a'1a'0 is the perturbation factor S of the 4-bit binary sequence. F Although S F T R Control, generate S F The value period is also 8 seconds, but S F It is used to identify the target in combat. In order to improve the security of this important data, S F It is sent to the host each time the cipher machine interacts with the host in plaintext and ciphertext.

[0117] Step 26: Generate a 7-bit binary pseudo-random sequence for providing a response signal for obtaining intelligence data using a pseudo-random sequence, and use the reference time factor T R The timing of extracting the 7-bit binary pseudo-random sequence is limited. The final sequence obtained is the disturbance factor S of the 7-bit binary sequence used for situational awareness or obtaining intelligence data. R Since the balance, run distribution, and autocorrelation characteristics of the M sequence are extremely similar to those of a random sequence, and the number of sequences it contains is larger, the pseudo-random sequence generation algorithm uses the characteristic polynomial x 7 +x 3 +1 M sequence generation method, the specific generation process is: set the initial value of the 7-bit M sequence generator to a6a5a4a3a2a1a0=0010001 (the user can set different initial values, and the initial values ​​of the cipher machine equipped with any platform interrogator or transponder to run the algorithm must be exactly the same); complete the operation of the nonlinear feedback shift register under the triggering of the clock signal or periodic signal, that is, perform the assignment operation a' 0＝ a1、a' 1＝ a2、a' 2＝ a3、a' 3＝ a4、a' 4＝ a5、a' 5＝ a6、a' Completion and reference time factor T R When the same number of shift operations are performed (in order to improve its randomness, the reference time factor T calculated by using time data such as year, month, day, minute, second, etc. or several of them can also be used R To control the number of shift operations), the value of a'6a'5a'4a'3a'2a'1a'0 is the perturbation factor S of the 7-bit binary sequence. R . Due to S R T R Control, while T R The cycle of value output is 8 seconds, so S R The value output cycle is 8 seconds.

[0118] Furthermore, the step 3 specifically includes:

[0119] Step 31: Using the current time base factor T R and the interrogation signal disturbance factor S I The disturbance value S that generates the first synchronization header IP1 , its disturbance value S IP1 The specific algorithm process for obtaining is: If T R mod 3=0, then S IP1 =(int(S I / 16))mod8; if T R mod 3=1, then S IP1 =(int(S I / 16))mod 8+8; if T R mod 3=2, then S IP1 =(int(S I / 16))mod 8+16. Finally, the disturbance value is used to generate the time domain position of the first synchronization head. The time interval between the falling edge of the synchronization head pulse and the falling edge of the fourth pulse is: inherent position + disturbance position = 40.375us + S IP1 ×2×0.0625us (since each synchronization header is composed of 16 chips and uses a 16MHz transmission rate, 0.0625 is the time domain width of each chip). R and the interrogation signal disturbance factor S I All of them change randomly, and the corresponding random algorithm is used to generate the disturbance value S IP1 ,Therefore, the position of the first synchronization head will also change randomly.

[0120] Step 32: Using the current time base factor T R and the interrogation signal disturbance factor S I Generate the disturbance value S of the second synchronization head IP2 , its disturbance value SIP2 The specific algorithm process for obtaining is: If T R mod 3=0, then S IP2 =(int(S I / 4))mod 4+16; if T R mod 3=1, then S IP2 =(int(S I / 4))mod 4; if T R mod 3=2, then S IP2 =(int(S I / 4))mod 4+20. Finally, the disturbance value is used to generate the time domain position of the second synchronization head. The time interval between the falling edge of the synchronization head pulse and the falling edge of the fourth pulse is: inherent position + disturbance position = 23us + S IP2 ×2×0.0625us, due to the time base factor T R and the interrogation signal disturbance factor S I All of them change randomly, and the corresponding random algorithm is used to generate the disturbance value S IP2 ,Therefore, the position of the second synchronization head will also change randomly.

[0121] Step 33: Using the current time base factor T R and the interrogation signal disturbance factor S I The disturbance value S that generates the third synchronization header IP3 , its disturbance value S P3 The specific algorithm process for obtaining is: If T R mod 3=0, then S IP3 =S I mod 4+8; if T R mod 3=1, then S IP3 =S I mod 4+4; if T R mod 3=2, then S IP3 =S I mod 4. Finally, the disturbance value is used to generate the time domain position of the third synchronization head. The time interval between the falling edge of the synchronization head pulse and the falling edge of the fourth pulse is: inherent position + disturbance position = 13us + S IP3 ×2×0.0625us, due to the time base factor T R and the interrogation signal disturbance factor S I All of them change randomly, and the corresponding random algorithm is used to generate the disturbance value S IP3 ,Therefore, the position of the third synchronization head will also change randomly.

[0122] Furthermore, the step 4 specifically includes:

[0123] Step 41: The answering machine receives the time reference factor T from the cipher machine that matches it. R and the interrogation signal disturbance factor S I , and save it from the current T R The data of three consecutive times up to now, namely T R , T R -1, T R -2 and the corresponding S I , S I1 , S I2 .

[0124] Step 42: Utilizing the Stored T R , T R -1, T R -2 and corresponding S I , S I1 , S I2 Data, use the algorithm of step 31 to calculate the position of the first synchronization head pulse, and then compare it with the corresponding pulse position extracted from the received inquiry signal. If the error is within ±15.625ns, subsequent processing is performed; if the error exceeds ±15.625ns (1 / 4 code chip width), it will not be received.

[0125] Step 43: Utilizing the Stored T R , T R -1, T R -2 and corresponding S I , S I1 , S I2 Data, use the algorithm of step 32 to calculate the expected position of the second synchronization head pulse, and then compare it with the corresponding pulse position extracted from the received interrogation signal. If the error is within ±15.625ns, subsequent processing is performed; if the error exceeds ±15.625ns, it will not be received.

[0126] Step 44: Utilizing the Stored T R , T R -1, T R -2 and corresponding S I , S I1 , S I2 Data, use the algorithm of step 33 to calculate the expected position of the third synchronization head pulse, and then compare it with the corresponding pulse position extracted from the received interrogation signal. If the error is within ±15.625ns, subsequent processing is performed; if the error exceeds ±15.625ns, it will not be received.

[0127] Furthermore, the step 5 specifically includes:

[0128] Step 51: If obtaining intelligence information, the current time reference factor T is required R and the disturbance factor S of the intelligence data reply signal R Generate the disturbance value S of the first synchronization header in the intelligence response data RP1 , its disturbance value S RP1 The specific algorithm process for obtaining is: If T R mod 3=0, then S RP1 =(int(S R / 16))mod 8; if T R mod 3=1, then S RP1 =(int(S R / 16))mod 8+8; if T R mod 3=2, then S RP1 =(int(S R / 16))mod 8+16. Finally, the disturbance value is used to generate the time domain position of the first synchronization head. The time interval between the falling edge of the synchronization head pulse and the falling edge of the fourth pulse is: inherent position + disturbance position = 26.625us + S RP1 ×2×0.0625us. Time base factor T R and the response signal disturbance factor S R All of them change randomly, and the corresponding random algorithm is used to generate the disturbance value S RP1 ,Therefore, the position of the first synchronization head will also change randomly.

[0129] Step 52: If obtaining intelligence information, the current time reference factor T is required R and intelligence data (situational awareness) response signal disturbance factor S R The disturbance value S of the second synchronization header in the generated intelligence response data RP2 , its disturbance value S RP2 The specific algorithm process for obtaining is: If T R mod 3=0, then S RP2 =(int(S R / 4))mod 4+16; if T R mod3=1, then S RP2 =(int(S R / 4))mod 4; if T R mod 3=2, then S RP2 =(int(S R / 4))mod 4+20. Finally, the disturbance value is used to generate the time domain position of the second synchronization head. The time interval between the falling edge of the synchronization head pulse and the falling edge of the fourth pulse is: inherent position + disturbance position = 17.25us + S RP2×2×0.0625us, due to the time base factor T R and the response signal disturbance factor S R All of them change randomly, and the corresponding random algorithm is used to generate the disturbance value S RP2 ,Therefore, the position of the second synchronization head will also change randomly.

[0130] Step 53: If obtaining intelligence information, the current time reference factor T is required R and intelligence data (situational awareness) response signal disturbance factor S R The disturbance value S of the third synchronization header in the generated intelligence response data RP3 , its disturbance value S RP3 The specific algorithm process for obtaining is: If T R mod 3=0, then S RP3 =S R mod 4+8; if T R mod 3=1, then S RP3 =S R mod 4+4; if T R mod 3=2, then S RP3 =S R mod 4. Finally, the disturbance value is used to generate the time domain position of the third synchronization head. The time interval between the falling edge of the synchronization head pulse and the falling edge of the fourth pulse is: inherent position + disturbance position = 5.0us + S RP3 ×2×0.0625us, due to the time base factor T R and the response signal disturbance factor S R All of them change randomly, and the corresponding random algorithm is used to generate the disturbance value S RP3 ,Therefore, the position of the third synchronization head will also change randomly.

[0131] Step 54: If identity recognition is required, the disturbance value S of the first synchronization header in the identity recognition response signal FP1 and the identity recognition response signal disturbance factor S F The disturbance value is used to generate the time domain position of the first synchronization head. The time interval between the falling edge of the synchronization head pulse and the falling edge of the second pulse is: inherent position + disturbance position = 3.0us + S F ×2×0.0625us, due to the disturbance factor S of each identity recognition response signal F changes randomly, so the position of the first sync header also changes randomly.

[0132] Furthermore, the step 6 specifically includes:

[0133] Step 61: The interrogator receives the time reference factor T from its matching cipher machine.R , the disturbance factor S of the identity recognition response signal F and the disturbance factor S of the reply signal used to provide intelligence data R , and save it from the current T R The data of three consecutive times up to now, namely T R , T R -1, T R -2 and the corresponding S F , S F1 , S F2 With S R , S R1 , S R2 .

[0134] Step 62: After receiving the response signal, if the interrogator obtains intelligence information, it uses the stored T R , T R -1, T R -2 and corresponding S R , S R1 , S R2 Data, use the algorithm of step 51 to calculate the expected position of the first synchronization head pulse, and then compare it with the corresponding pulse position extracted from the received response signal. If the error is within ±15.625ns, subsequent processing is performed; if the error exceeds ±15.625ns, it will not be received.

[0135] Step 63: After receiving the response signal, if the interrogator obtains intelligence information, it uses the stored T R , T R -1, T R -2 and corresponding S R , S R1 , S R2 Data, use the algorithm of step 52 to calculate the expected position of the second synchronization head pulse, and then compare it with the corresponding pulse position extracted from the received response signal. If the error is within ±15.625ns, subsequent processing is performed; if the error exceeds ±15.625ns, it will not be received.

[0136] Step 64: After receiving the response signal, if the interrogator obtains intelligence information, it uses the stored T R , T R -1, T R -2 and corresponding S R , S R1 , S R2Data, use the algorithm of step 53 to calculate the expected position of the third synchronization head pulse, and then compare it with the corresponding pulse position extracted from the received response signal. If the error is within ±15.625ns, subsequent processing is performed; if the error exceeds ±15.625ns, it will not be received.

[0137] Step 64: After the interrogator receives the response signal, if it is identity recognition response data, it uses the stored T R , T R -1, T R -2 and corresponding S F , S F1 , S F2 Data, using the algorithm of step 54, calculate the expected position of the first synchronization head pulse, and then compare it with the corresponding pulse position extracted from the received response signal. If the error is within ±15.625ns, subsequent processing is performed; if the error exceeds ±15.625ns, it is not received.

[0138] Example description:

[0139] Figure 1 This is a flow chart for controlling the time data of the base time factor and the disturbance factor when the IFF system is working. The key generation and management center is the source of the time data. The time can be the system time, or manually set time for confidentiality and security. Once the time is determined, all equipment of the IFF system will work together with this time as the reference. In this figure, the key generation and management center is generally placed in the national military command and control center, and the key distribution management center is generally placed in the military district or service combat command center. When the key generation and management center transmits data to the key distribution management terminal, it can use a wired or wireless method with a high degree of confidentiality, or it can use a storage medium with a high degree of confidentiality to transmit manually; the key loader obtains the time data from the key distribution management terminal and loads it to the cipher machine of each combat platform; the cipher machine generates the time reference factor T according to the reference time data R , and a pseudo-random algorithm is used to generate the disturbance factor S I、 S F , S R The key machine must be used in conjunction with the interrogator, transponder, and interrogator-responder on each combat platform. Each host uses the time reference factor T generated by the received cipher machine. R and the disturbance factor S I、 S F , S R , using algorithms to generate signals (inquiry or response) and process the received signals to suppress interference signals. Interrogators or interrogator-responder integrated machines are generally equipped to combat platforms with active attack capabilities.

[0140] Figure 2 It is the waveform diagram of the inquiry and response signals before and after the improvement. Among them, there are two types of improved response signals, and both have synchronization heads. One is the response signal for determining the identity of the target at the moment of attack. Therefore, the duration of the signal waveform is relatively short, in order to minimize the identification time and improve the real-time performance of the enemy identification system; the other is to provide the intelligence response signal required for pre-combat deployment and situation awareness during combat. Therefore, this type of response signal must contain data such as the combat platform code, longitude, latitude, altitude, etc., and the response signal waveform lasts longer.

[0141] Figure 3 The cipher machine uses the received reference time data to generate the reference time factor T R The processing flow is to obtain T R The value is calculated in 8-second intervals. The time required for the interrogator and transponder to work together is taken into account when setting this value. This time includes the time it takes for the cipher machine to transmit data to the interrogator or transponder, the time it takes for the interrogator to generate an interrogation signal, the time it takes for the transponder to receive and process the interrogation signal, the time it takes for the transponder to generate a response signal, the time it takes for the interrogator to receive and process the response signal, the propagation time of the 1030MHz carrier interrogation signal between the interrogator and the transponder, and the propagation time of the 1090MHz carrier response signal between the transponder and the interrogator. During the processing, when the reference time reaches an integer multiple of 8 seconds, T is calculated once. R , and output T R , that is, T R The output is in 8 second cycles.

[0142] Figure 4 It is the disturbance factor S of the synchronization header that generates the interrogation signal in the cipher machine. I The implementation process uses the M pseudo-random sequence generation algorithm. When the time reference factor T is first received R When using T R Control the shift times of the shift register to increase the disturbance factor S I To obtain randomness, other pseudo-random sequence generation algorithms can be used, or time data such as year, month, day, minute, second, etc. or a reference time factor T calculated from several of these time data can be introduced. R To control the number of shift operations. In the process of algorithm implementation, it is necessary to assign an initial value to the a6a5a4a3a2a1a0 sequence. In this example, a6a5a4a3a2a1a0=1001000. Users can also set different initial values, but the initial values ​​of the cipher machine running the algorithm on any platform interrogator or transponder must be exactly the same. Considering the large number of shifts, in order to improve the real-time performance of the algorithm, it is necessary to shorten the shift processing time of the shift register. Therefore, in the FPGA, the first received TR and subsequently receive T R The two cases are handled separately. In addition, the control clock of the shift register needs to be multiplied to above 100MHz. R control, therefore, S I The output is in 8 second cycles.

[0143] Figure 5 It is the synchronization head disturbance factor S that generates the identity recognition response signal in the cipher machine. F The implementation process uses the M pseudo-random sequence generation algorithm and uses the time base factor T R Control the shift times of the shift register to increase the disturbance factor S I To obtain randomness, other pseudo-random sequence generation algorithms can be used, or time data such as year, month, day, minute, second, etc. or a reference time factor T calculated from several of these time data can be introduced. R To control the number of shift operations. In the process of algorithm implementation, it is necessary to assign an initial value to the a3a2a1a0 sequence. In this example, a3a2a1a0=1001. Users can also set different initial values, but the initial values ​​of the cipher machine running the algorithm on any platform interrogator or transponder must be exactly the same. Considering the large number of shifts, in order to improve the real-time performance of the algorithm, it is necessary to shorten the shift processing time of the shift register. Therefore, in the FPGA, the first received T R and subsequently received T R The two cases are handled separately. In addition, the control clock of the shift register needs to be multiplied to above 100MHz. R Control, but S F It is used to identify the target in combat. In order to improve the security of this important data, S F It is sent to the host each time the cipher machine interacts with the host in plaintext and ciphertext.

[0144] Figure 6 It is the synchronization head disturbance factor S that generates the intelligence response signal in the cipher machine. R The implementation process uses the M pseudo-random sequence generation algorithm and uses the time base factor T R Control the shift times of the shift register to increase the disturbance factor S I To obtain randomness, other pseudo-random sequence generation algorithms can be used, or time data such as year, month, day, minute, second, etc. or a reference time factor T calculated from several of these time data can be introduced. RTo control the number of shift operations. In the process of algorithm implementation, it is necessary to assign an initial value to the a6a5a4a3a2a1a0 sequence. In this example, a6a5a4a3a2a1a0=0010001. Users can also set different initial values, but the initial values ​​of the cipher machine running the algorithm on any platform interrogator or transponder must be exactly the same. Considering the large number of shifts, in order to improve the real-time performance of the algorithm, it is necessary to shorten the shift processing time of the shift register. Therefore, in the FPGA, the first received T R and subsequently received T R The two cases are handled separately. In addition, the control clock of the shift register needs to be multiplied to above 100MHz. R control, therefore, S R The output is in 8 second cycles.

[0145] Figure 7 This is a flowchart of an algorithm for generating the first synchronization head position of the inquiry signal in step 1401 in an embodiment of the present invention. Other algorithms may also be used to generate the first synchronization head position of the inquiry signal.

[0146] Figure 8 This is a flowchart of an algorithm for generating the second synchronization head position of the inquiry signal in step 1402 in an embodiment of the present invention. Other algorithms may also be used to generate the second synchronization head position of the inquiry signal.

[0147] Fig. 9 This is a flowchart of an algorithm for generating the third synchronization head position of the inquiry signal in step 1403 in an embodiment of the present invention. Other algorithms may also be used to generate the third synchronization head position of the inquiry signal.

[0148] Fig.10 This is a flowchart of an algorithm for generating the first synchronization head position of the intelligence response signal in step 1501 in an embodiment of the present invention. Other algorithms may also be used to generate the first synchronization head position of the intelligence response signal.

[0149] Fig.11 This is a flowchart of an algorithm for generating the second synchronization head position of the intelligence response signal in step 1502 in an embodiment of the present invention. Other algorithms may also be used to generate the second synchronization head position of the intelligence response signal.

[0150] Fig.12 This is a flowchart of an algorithm for generating the third synchronization head position of the intelligence response signal in step 1503 in an embodiment of the present invention. Other algorithms may also be used to generate the third synchronization head position of the intelligence response signal.

[0151] Fig.13This is a flowchart of an algorithm for generating the first synchronization header position of the identity recognition response signal in step 1601 in an embodiment of the present invention. Other algorithms may also be used to generate the first synchronization header position of the identity recognition response signal.

[0152] Fig.14 1401, 1402, 1403. The corresponding processing flows are as follows: Figure 7 , Figure 8 , Fig. 9 In the flow chart, when determining whether the synchronization header is valid, the difference between the preset position and the actual position is required to be within ±15.625ns, where 15.625ns = the length of one chip representing the data bit (62.5ns) × 1 / 4.

[0153] Fig.15 1501, 1502, 1503. The corresponding processing flows are as follows: Fig.10 , Fig.11 , Fig.12 In the flow chart, when determining whether the synchronization header is valid, the difference between the preset position and the actual position is required to be within ±15.625ns, where 15.625ns = the length of one chip representing the data bit (62.5ns) × 1 / 4.

[0154] Fig.16 1 is a flowchart of the interrogator determining the validity of the synchronization header of the identity recognition response signal according to an embodiment of the present invention, including step 1601, and the corresponding processing flow is as follows: Fig.13 In the flow chart, when determining whether the synchronization header is valid, the difference between the preset position and the actual position is required to be within ±15.625ns, where 15.625ns = the length of one chip representing the data bit (62.5ns) × 1 / 4.

[0155] The above are preferred embodiments of the present invention. Any changes made according to the technical solution of the present invention, as long as the resulting functions do not exceed the scope of the technical solution of the present invention, belong to the protection scope of the present invention.

Claims

1. A processing method for improving the transmission security performance of a friend-or-foe identification system channel, characterized in that: The following steps are involved: Step 1: The key management subsystem generates relative reference time data and distributes it to the key loader, which loads the reference time data into the cipher machines located on the interrogator and transponder; Step 2: The cipher machine uses the reference time data to generate the time reference factor T R , and using the time reference factor T R As the initial value, the perturbation factor S for the interrogation signal is generated using a pseudo-random generation sequence. I , the disturbance factor S used for the identification response signal F , the disturbance factor S used for the intelligence data reply signal R ; and transmitted to the interrogator or transponder; Step 3: The interrogator receives the time reference factor T from its matching cipher machine. R and the interrogation signal disturbance factor S I , generating an interrogation signal of waveform frame change; Step 4: The answering machine receives the time reference factor T from the cipher machine that matches it. R and the interrogation signal disturbance factor S I , calculate the disturbance value of the corresponding synchronization head, calculate the expected position of the synchronization head, and compare it with the synchronization head position value of the received inquiry signal to determine its validity. If it is invalid, no response signal is generated to shield the interfering false inquiry signal; if it is valid, then perform subsequent processing; Step 5: If the interrogation signal is valid and legal, the transponder receives the time reference factor T from the cipher machine that matches it according to the interrogation signal type. R , the disturbance factor S of the identity recognition response signal F and the disturbance factor S used to provide the intelligence data reply signal R , generates a response signal with a waveform frame change. If identity recognition is required, the identity recognition response signal disturbance factor S is used F Generate a response signal with a waveform frame change. If you want to obtain intelligence information, you need to use the time reference factor T R and the disturbance factor S of the intelligence data reply signal R Generates a response signal of waveform frame change; Step 6: For both types of response signals, the interrogator receives the time reference factor T from the cipher machine that matches it. R , the disturbance factor S of the identity recognition response signal F and the disturbance factor S of the reply signal used to provide intelligence data R , calculate the disturbance value of the corresponding synchronization head, and compare it with the received response signal synchronization head disturbance value to determine its validity. If it is invalid, no response signal is generated and the interfering false response signal is shielded; if it is valid, subsequent processing is performed.

2. A processing method for improving the transmission security performance of a friend-or-foe identification system channel according to claim 1, characterized in that: Step 1 includes: Step 11: The key generation and management center generates relative reference time data including year, month, day, hour, minute and second; Step 12: The key generation and management center distributes the generated reference clock data and key data together to the key distribution management terminal of the theater or combat unit through a wired network or encrypted storage medium; Step 13: The key loader obtains the reference clock data and key data from the key distribution management terminal and loads them to the cipher machine located on the interrogator or transponder. The cipher machine uses the reference clock data to generate a 14-bit binary sequence of time reference factor T R , and use the time reference factor to generate the disturbance factor S.

3. A processing method for improving the transmission security performance of a friend-or-foe identification system channel according to claim 2, characterized in that: Step 2 includes: Step 21: The cipher machine uses the reference time data to correct its own time, and keeps the time of the cipher machine synchronized with the time of the current key management subsystem; Step 23: The cipher generates a reference time factor T using the currently received time data R ; Step 24: Generate a 7-bit binary pseudo-random sequence of the interrogation signal using a pseudo-random generation method, and use the reference time factor T R Limit the timing of extracting the 7-bit binary pseudo-random sequence. The final sequence obtained is the disturbance factor S I ; Step 25: Generate a 4-bit binary pseudo-random sequence for the identity recognition response signal using a pseudo-random generation method, and use the reference time factor T R The timing of extracting the 4-bit binary pseudo-random sequence is limited. The final sequence obtained is the 4-bit binary perturbation factor S used to identify the enemy attribute response signal. F ; Step 26: Generate a 7-bit binary pseudo-random sequence for providing a response signal for obtaining intelligence data using a pseudo-random sequence, and use the reference time factor T R The timing of extracting the 7-bit binary pseudo-random sequence is limited. The final sequence obtained is the disturbance factor S of the 7-bit binary sequence used for situational awareness or obtaining intelligence data. R .

4. A processing method for improving the transmission security performance of a friend-or-foe identification system channel according to claim 3, characterized in that: Step 3 includes: Step 31: Using the current time base factor T R and the interrogation signal disturbance factor S I The disturbance value S that generates the first synchronization header IP1 , its disturbance value S IP1 The specific algorithm process for obtaining is: If T R mod 3=0, then S IP1 =(int(S I / 16))mod 8; If T R mod 3=1, then S IP1 =(int(S I / 16))mod 8+8; If T R mod 3=2, then S IP1 =(int(S I / 16))mod 8+16; Finally, the disturbance value is used to generate the time domain position of the first synchronization head. The time interval between the falling edge of the synchronization head pulse and the falling edge of the fourth pulse is: Natural position + disturbance position = 40.375us + S IP1 ×2×0.0625us; Step 32: Using the current time base factor T R and the interrogation signal disturbance factor S I Generate the disturbance value S of the second synchronization head IP2 , its disturbance value S IP2 The specific algorithm process for obtaining is: If T R mod 3=0, then S IP2 =(int(S I / 4))mod 4+16; If T R mod 3=1, then S IP2 =(int(S I / 4))mod 4; If T R mod 3=2, then S IP2 =(int(S I / 4))mod 4+20; Finally, the disturbance value is used to generate the time domain position of the second synchronization head. The time interval between the falling edge of the synchronization head pulse and the falling edge of the fourth pulse is: Intrinsic position + disturbance position = 23us + S IP2 ×2×0.0625us; Step 33: Using the current time base factor T R and the interrogation signal disturbance factor S I The disturbance value S that generates the third synchronization header IP3 , its disturbance value S P3 The specific algorithm process for obtaining is: If T R mod 3=0, then S IP3 =S I mod 4+8; If T R mod 3=1, then S IP3 =S I mod 4+4; If T R mod 3=2, then S IP3 =S I mod 4; Finally, the disturbance value is used to generate the time domain position of the third synchronization head. The time interval between the falling edge of the synchronization head pulse and the falling edge of the fourth pulse is: Intrinsic position + disturbance position = 13us + S IP3 ×2×0.0625us.

5. A processing method for improving the transmission security performance of a friend-or-foe identification system channel according to claim 4, characterized in that: Step 4 includes: Step 41: The answering machine receives the time reference factor T from the cipher machine that matches it. R and the interrogation signal disturbance factor S I , and save it from the current T R The data of three consecutive times up to now, namely T R , T R -1, T R -2 and the corresponding S I , S I1 , S I2 ; Step 42: Utilizing the Stored T R , T R -1, T R -2 and corresponding S I , S I1 , S I2 Data, using the algorithm of step 31, calculate the expected position of the first synchronization head pulse, and then compare it with the corresponding pulse position extracted from the received interrogation signal. If the error is within ±15.625ns, it will be processed later; if the error exceeds ±15.625ns, it will not be received; Step 43: Utilizing the Stored T R , T R -1, T R -2 and corresponding S I , S I1 , S I2 The data is then processed by using the algorithm in step 32 to calculate the position of the second synchronization head pulse, and then compared with the corresponding pulse position extracted from the received interrogation signal. If the error is within ±15.625ns, the data is processed; if the error exceeds ±15.625ns, the data is not received. Step 44: Utilizing the Stored T R , T R -1, T R -2 and corresponding S I , S I1 , S I2 Data, use the algorithm of step 33 to calculate the expected position of the third synchronization head pulse, and then compare it with the corresponding pulse position extracted from the received interrogation signal. If the error is within ±15.625ns, subsequent processing is performed; if the error exceeds ±15.625ns, it will not be received.

6. A processing method for improving the transmission security performance of a friend-or-foe identification system channel according to claim 5, characterized in that: Step 5 includes: Step 51: If obtaining intelligence information, the current time reference factor T is required R and the disturbance factor S of the intelligence data reply signal R Generate the disturbance value S of the first synchronization header in the intelligence response data RP1 , its disturbance value S RP1 The specific algorithm process for obtaining is: If T R mod 3=0, then S RP1 =(int(S R / 16))mod 8; If T R mod 3=1, then S RP1 =(int(S R / 16))mod 8+8; If T R mod 3=2, then S RP1 =(int(S R / 16))mod 8+16; Finally, the disturbance value is used to generate the time domain position of the first synchronization head. The time interval between the falling edge of the synchronization head pulse and the falling edge of the fourth pulse is: Intrinsic position + disturbance position = 26.625us + S RP1 ×2×0.0625us; Step 52: If obtaining intelligence information, the current time reference factor T is required R and the disturbance factor S of the intelligence data reply signal R The disturbance value S of the second synchronization header in the generated intelligence response data RP2 , its disturbance value S RP2 The specific algorithm process for obtaining is: If T R mod 3=0, then S RP2 =(int(S R / 4))mod 4+16; If T R mod 3=1, then S RP2 =(int(S R / 4))mod 4; If T R mod 3=2, then S RP2 =(int(S R / 4))mod 4+20; Finally, the disturbance value is used to generate the time domain position of the second synchronization head. The time interval between the falling edge of the synchronization head pulse and the falling edge of the fourth pulse is: Intrinsic position + disturbance position = 17.25us + S RP2 ×2×0.0625us; Step 53: If obtaining intelligence information, the current time reference factor T is required R and the disturbance factor S of the intelligence data reply signal R The disturbance value S of the third synchronization header in the generated intelligence response data RP3 , its disturbance value S RP3 The specific algorithm process for obtaining is: If T R mod 3=0, then S RP3 =S R mod 4+8; If T R mod 3=1, then S RP3 =S R mod 4+4; If T R mod 3=2, then S RP3 =S R mod 4; Finally, the disturbance value is used to generate the time domain position of the third synchronization head. The time interval between the falling edge of the synchronization head pulse and the falling edge of the fourth pulse is: Intrinsic position + disturbance position = 5.0us + S RP3 ×2×0.0625us; Step 54: If identity recognition is required, the disturbance value S of the first synchronization header in the identity recognition response signal FP1 and the identity recognition response signal disturbance factor S F The same; the disturbance value is used to generate the time domain position of the first synchronization head. The time interval between the falling edge of the synchronization head pulse and the falling edge of the second pulse is: Intrinsic position + disturbance position = 3.0us + S F ×2×0.0625us.

7. A processing method for improving the transmission security performance of a friend-or-foe identification system channel according to claim 6, characterized in that: Step 6 includes: Step 61: The interrogator receives the time reference factor T from its matching cipher machine. R , the disturbance factor S of the identity recognition response signal F and the disturbance factor S of the reply signal used to provide intelligence data R , and save it from the current T R The data of three consecutive times up to now, namely T R , T R -1, T R -2 and the corresponding S F , S F1 , S F2 With S R , S R1 , S R2 ; Step 62: After receiving the response signal, if the interrogator obtains intelligence information, it uses the stored T R , T R -1, T R -2 and corresponding S R , S R1 , S R2 Data, using the algorithm of step 51, calculate the position of the first synchronization head pulse, and then compare it with the corresponding pulse position extracted from the received response signal. If the error is within ±15.625ns, perform subsequent processing; if the error exceeds ±15.625ns, do not receive it; Step 63: After receiving the response signal, if the interrogator obtains intelligence information, it uses the stored T R , T R -1, T R -2 and corresponding S R , S R1 , S R2 The data is received, and the algorithm of step 52 is used to calculate the position of the second synchronization head pulse, and then the position is compared with the corresponding pulse position extracted from the received response signal. If the error is within ±15.625ns, subsequent processing is performed; if the error exceeds ±15.625ns, it is not received; Step 64: After receiving the response signal, if the interrogator obtains intelligence information, it uses the stored T R , T R -1, T R -2 and corresponding S R , S R1 , S R2 The data is received, and the algorithm of step 53 is used to calculate the position of the third synchronization head pulse, and then it is compared with the corresponding pulse position extracted from the received response signal. If the error is within ±15.625ns, subsequent processing is performed; if the error exceeds ±15.625ns, it is not received; Step 64: After the interrogator receives the response signal, if it is identity recognition response data, it uses the stored T R , T R -1, T R -2 and corresponding S F , S F1 , S F2 Data, using the algorithm of step 54, calculate the expected position of the first synchronization head pulse, and then compare it with the corresponding pulse position extracted from the received response signal. If the error is within ±15.625ns, subsequent processing is performed; if the error exceeds ±15.625ns, it is not received.

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