Secondary radar reply pulse extraction method based on sum and difference dual channel amplitude and phase characteristics

Abstract

The present invention discloses a secondary radar reply pulse extraction method based on sum / difference dual channel amplitude and phase characteristics, which comprises: the air traffic control secondary radar adopts sum / difference beam to receive reply signal; extracts reply pulse PSV through 6dB threshold and background noise threshold respectively; extracts reply signal pulse PSV by threshold judgment, and extracts effective pulse by background noise threshold. The present invention adopts the amplitude of sum / difference dual channel as the basis of pulse extraction, which can effectively improve the extraction probability of pulse; adopts the change of phase difference to judge the position of pulse interleaving and extracts the false edge of pulse, which can effectively improve the extraction probability of interleaved pulse; adopts two-level threshold to judge pulse edge, that is, adopts 6dB threshold to judge pulse true edge and adopts 1.5dB threshold to judge pulse false edge, which can effectively improve the extraction probability of interleaved pulse.

Description

Technical Field

[0001] The invention relates to the field of communication technology, in particular to a secondary radar response pulse extraction method based on sum and difference dual-channel amplitude and phase characteristics. Background Art

[0002] Secondary radar can accurately detect the aircraft's position, altitude, and speed information, and is widely used in air traffic control fields such as military and civil route flight monitoring, daily and military exercise flight support, etc. When the aircraft is too close, the flight traffic is large, and the electromagnetic environment is complex, the secondary radar's detection performance will be significantly reduced, and even code jumps and altitude jumps will cause long-term detection code errors. After analysis, since the secondary radar's reply signal is a sequence of pulses, the root cause of the above problems is the interweaving of reply codes and the interweaving of reply codes and reflection codes, resulting in errors in aircraft code altitude extraction and a sharp deterioration in detection position accuracy.

[0003] The existing conventional mode response pulse extraction method: only uses the amplitude signal of the sum channel as the basis for pulse extraction. When there is pulse interleaving and cancellation in the sum channel, it will directly lead to the loss of pulse extraction; only uses a 6dB threshold to judge the pulse edge. When the amplitude change exceeds the threshold after the pulse interleaving part is superimposed or cancelled, it will cause the failure of pulse pseudo-front edge extraction and even cause the extracted pulse to split, eventually leading to the loss of pulse extraction.

[0004] The existing conventional mode response pulse extraction method: only uses the amplitude signal of the sum channel as the basis for pulse extraction. When there is pulse interleaving and cancellation in the sum channel, it will directly lead to the loss of pulse extraction; only uses a 6dB threshold to judge the pulse edge. When the amplitude change exceeds the threshold after the pulse interleaving part is superimposed or cancelled, it will cause the failure of pulse pseudo-front edge extraction and even cause the extracted pulse to split, eventually leading to the loss of pulse extraction. Summary of the invention

[0005] In view of this, the present invention provides a secondary radar response pulse extraction method based on sum and difference dual-channel amplitude and phase characteristics, which can effectively improve the extraction probability of pulses and interleaved pulses.

[0006] The present invention discloses a secondary radar response pulse extraction method based on sum and difference dual-channel amplitude and phase characteristics, comprising:

[0007] Step 1: The air traffic control secondary radar uses the sum / difference beam to receive the reply signal;

[0008] Step 2: Extract the response pulse PSV through the 6dB threshold and the noise floor threshold respectively;

[0009] Step 3: Use threshold judgment to extract the response signal pulse PSV, and use the background noise threshold to extract the effective pulse.

[0010] Furthermore, in step 2:

[0011] Extract the response pulse PSV through the 6dB threshold, including:

[0012] The starting position where the signal amplitude changes by more than 6dB relative to the pulse top amplitude is the true position of the pulse front and back edges. The 6dB threshold judgment method is used to extract the response signal pulse PSV, so as to facilitate the subsequent accurate extraction of the true edge of the pulse.

[0013] Extract the response pulse PSV through the noise floor threshold, including:

[0014] The amplitude change of the top of the interleaved pulse may exceed the edge judgment threshold of 6dB. When the signal is greater than the noise floor threshold, the noise floor pulse signal NPSV is extracted.

[0015] Further, the extracting the response pulse PSV by the 6dB threshold further includes:

[0016] When the signal amplitude is greater than the noise floor threshold and meets the rising and falling edge judgment conditions of the 6dB threshold, the 6dB pulse signal EPSV is extracted.

[0017] Furthermore, the step 3 comprises:

[0018] Step 31: extracting the amplitude true pulse edge through the sum channel / difference channel respectively;

[0019] Step 32: extracting amplitude pseudo pulse edges respectively through the sum channel / difference channel;

[0020] Step 33: extracting the phase difference pseudo pulse edge;

[0021] Step 34: Fusion the amplitude true pulse edge, the amplitude pseudo pulse edge, and the phase difference pseudo pulse edge.

[0022] Furthermore, the step 31 comprises:

[0023] According to the EPSV and NPSV of the sum channel, the true pulse edge ALE of the sum channel is extracted; according to the EPSV and NPSV of the difference channel, the true pulse edge ALE of the difference channel is extracted; the leading edge of the 6dB pulse EPSV is taken as the true pulse leading edge ALE;

[0024] The existence of two or more interleaved pulses is determined by judging the width of the background noise pulse NPSV, that is: starting from the trailing edge of the 6dB pulse EPSV, when the width of the background noise pulse NPSV is greater than or equal to 0.6us, it is considered that an interleaved pulse exists, and the amplitude true pulse edge PLE is obtained 0.45us ahead of the trailing edge of the 6dB pulse EPSV.

[0025] Further, the step 32 comprises:

[0026] Extract the pseudo pulse edge ELE of the sum channel according to the EPSV and NPSV of the sum channel and the sum channel amplitude;

[0027] According to the EPSV and NPSV of the difference channel and the amplitude of the difference channel, the pseudo pulse edge ELE of the difference channel is extracted;

[0028] In order to extract the change of the subtle edge signal at the top of the pulse and identify whether the current position is a valid pulse edge, it is also necessary to judge the pseudo pulse edge obtained by amplitude detection; among them, 1.5dB is set as the judgment threshold of the subtle edge signal change at the top of the pulse, and the judgment threshold can be adjusted according to the system characteristics. In addition, the judgment time threshold of the subtle edge signal change at the top of the pulse is set to 0.1us.

[0029] Furthermore, the judgment condition of the pseudo pulse front edge obtained by amplitude detection is:

[0030] There is no true pulse edge within ±0.1us of the current position;

[0031] There is no true pulse edge within 0.45us±0.1us from the current position;

[0032] Calculated backward from the current position, the background noise pulse width is ≥ 0.45us;

[0033] The judgment condition of the pseudo pulse trailing edge obtained by amplitude detection is:

[0034] There is no true pulse edge within 0.45us±0.1us from the current position;

[0035] Calculate forward from the current position, the background noise pulse width ≥ 0.45us;

[0036] According to the EPSV and NPSV of the sum channel, the amplitude of the sum channel, and the conditions for judging the pseudo pulse edge obtained by amplitude detection, the positions that conflict with the true pulse edges of the sum and difference channels are eliminated to obtain the pseudo pulse edge ELE of the sum channel;

[0037] According to the EPSV and NPSV of the difference channel, the amplitude of the difference channel, and the conditions for judging the pseudo pulse edge obtained by amplitude detection, the positions that conflict with the true pulse edges of the sum and difference channels are eliminated to obtain the pseudo pulse edge ELE of the difference channel.

[0038] Further, the step 33 comprises:

[0039] In order to extract the change of the phase difference of the sum / difference channel inside the pulse and identify whether the current position is a valid phase difference pulse edge, it is also necessary to judge the pseudo pulse edge obtained by phase difference detection.

[0040] Furthermore, the condition for judging the pseudo pulse leading edge obtained by phase difference detection is:

[0041] There is no true pulse edge within ±0.1us of the current position; wherein the true pulse edge includes the true pulse edge ALE of the sum channel, the true pulse edge PLE of the sum channel, the true pulse edge ALE of the difference channel, and the true pulse edge PLE of the difference channel;

[0042] There is no true pulse edge within 0.45us±0.1us from the current position;

[0043] Calculated backward from the current position, the background noise pulse width is ≥ 0.45us;

[0044] The conditions for judging the trailing edge of the pseudo pulse obtained by phase difference detection are:

[0045] There is no true pulse edge within 0.45us±0.1us from the current position;

[0046] Calculate forward from the current position, the background noise pulse width ≥ 0.45us;

[0047] A phase pseudo pulse edge PELE is generated at the position of the pseudo pulse leading edge obtained by judging the pseudo pulse edge obtained by phase difference detection or at the position 0.45 us in advance of the pseudo pulse trailing edge.

[0048] Further, the step 34 comprises:

[0049] The true pulse edge ALE of the sum channel, the true pulse edge PLE of the sum channel, the false pulse edge ELE of the sum channel, the true pulse edge ALE of the difference channel, the true pulse edge PLE of the difference channel, the false pulse edge ELE of the difference channel, and the false pulse edge PELE of the phase difference are integrated. Taking the true pulse edge detected first as the reference, the false pulse edge whose position overlaps within ±0.1us and the true pulse edge within 0.1us after the current edge position are eliminated to obtain the final pulse edge PSVEDGE output.

[0050] Due to the adoption of the above technical scheme, the present invention has the following advantages: 1) Since the probability of the amplitudes of the sum / difference channels being simultaneously superimposed or offset is relatively small in the case of pulse interleaving, the amplitudes of the sum / difference dual channels are used as the basis for pulse extraction, which can effectively improve the probability of pulse extraction; 2) Since there is a stable phase difference between the sum / difference channel signals of the non-interleaved pulses within the effective beam width, the change in phase difference can be used to determine the position of pulse interleaving and extract the false edge of the pulse, which can effectively improve the probability of extracting the interleaved pulse; 3) A two-level threshold is used for pulse edge judgment, that is, a 6dB threshold is used to judge the true edge of the pulse and a 1.5dB threshold is used to judge the false edge of the pulse, which can effectively improve the probability of extracting the interleaved pulse. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0052] Figure 1 A schematic diagram of 6dB pulse extraction according to an embodiment of the present invention;

[0053] Figure 2 A schematic diagram of background noise pulse extraction according to an embodiment of the present invention;

[0054] Figure 3 A schematic diagram of a true pulse edge extraction of amplitude according to an embodiment of the present invention;

[0055] Figure 4 A schematic diagram of a pseudo pulse edge for amplitude extraction according to an embodiment of the present invention;

[0056] Figure 5 This is a schematic diagram of the relative positions of antennas of target 1 and target 2 according to an embodiment of the present invention;

[0057] Figure 6 A schematic diagram of the sum / difference beam phase difference of a target 1 and a target 2 according to an embodiment of the present invention;

[0058] Figure 7 A schematic diagram of the amplitude and phase of an antenna beam main lobe (sum / difference beam) according to an embodiment of the present invention;

[0059] Figure 8 A schematic diagram of a phase extraction pulse edge according to an embodiment of the present invention;

[0060] Fig. 9 The present invention is a flowchart of a method for extracting secondary radar response pulses based on sum and difference dual-channel amplitude and phase characteristics according to an embodiment of the present invention. DETAILED DESCRIPTION

[0061] The present invention is further described in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field should fall within the scope of protection of the embodiments of the present invention.

[0062] The invention relates to a secondary radar conventional mode reply pulse extraction method based on sum / difference dual-channel amplitude and phase characteristics. Since the probability that the amplitudes of the sum / difference channels are simultaneously superimposed or offset is small in the case of pulse interleaving, the amplitudes of the sum / difference dual-channels are used as the basis for pulse extraction, which can effectively improve the probability of pulse extraction; since within the effective beam width, there is a stable phase difference between the sum / difference two-channel signals of pulses that are not interleaved, the change of the phase difference can be used to judge the position of pulse interleaving and extract the false edge of the pulse, which can effectively improve the probability of extracting the interleaved pulse; and two-level thresholds are used to judge the pulse edge, that is, a 6dB threshold is used to judge the true edge of the pulse and a 1.5dB threshold is used to judge the false edge of the pulse, which can effectively improve the probability of extracting the interleaved pulse.

[0063] This method requires the amplitude and phase of the sum / difference dual channels as input, extracts pulses through the changes in amplitude and phase, and uses a two-level amplitude threshold to judge the true edge / false edge of the interleaved pulse, which can improve the probability and accuracy of secondary radar conventional mode reply signal pulse extraction.

[0064] Terminology explanation:

[0065] PSV: Pulse Detection Video Signal

[0066] ALE: Pulse detection 6dB true leading edge signal

[0067] PLE: Pulse detection 6dB trailing edge to extrapolate true leading edge signal

[0068] ELE: Pulse detection amplitude pseudo leading edge signal

[0069] PELE: Pulse detection phase difference pseudo leading edge signal

[0070] EPSV: Pulse 6dB detection video signal

[0071] NPSV: Noise Pulse Detection Video Signal

[0072] PSVEDGE: Pulse detection leading edge signal

[0073] See also Fig. 9 The present invention provides an embodiment of a method for extracting a secondary radar reply pulse based on sum and difference dual-channel amplitude and phase characteristics, the method comprising the following steps:

[0074] Step 1: The air traffic control secondary radar uses the sum / difference beam to receive the reply signal;

[0075] Step 2: Extract the response pulse PSV through the 6dB threshold and the noise floor threshold respectively;

[0076] Step 3: Use threshold judgment to extract the response signal pulse PSV, and use the background noise threshold to extract the effective pulse.

[0077] In order to extract the pulse edge of the response signal more accurately and with higher probability, this section first selects three independent channels, namely the sum channel amplitude, the difference channel amplitude, and the sum / difference channel phase difference, to extract the pulse edge, and then performs pulse edge fusion judgment according to certain rules to obtain the final pulse edge signal and complete the pulse extraction process.

[0078] In this embodiment, in step 2:

[0079] Extract the response pulse PSV through the 6dB threshold, including:

[0080] The starting position where the signal amplitude changes by more than 6dB relative to the pulse top amplitude is the true position of the pulse front and back edges. The 6dB threshold judgment method is used to extract the response signal pulse PSV, so as to facilitate the subsequent accurate extraction of the true edge of the pulse.

[0081] Extract the response pulse PSV through the noise floor threshold, including:

[0082] The amplitude variation of the top of the interleaved pulse may exceed the 6dB edge judgment threshold. In order to avoid the resulting pulse splitting, valid pulses are detected as much as possible, and only the background noise threshold is used to extract valid pulses.

[0083] See also Figure 2 When the signal is greater than the noise floor threshold, the noise floor pulse signal NPSV is extracted.

[0084] In this embodiment, extracting the response pulse PSV through a 6dB threshold also includes:

[0085] See also Figure 1 When the signal amplitude is greater than the noise floor pulse extraction threshold and meets the rising edge and falling edge judgment conditions of the 6dB threshold, the 6dB pulse signal EPSV is extracted.

[0086] In this embodiment, step 3 includes:

[0087] Step 31: extracting the amplitude true pulse edge through the sum channel / difference channel respectively;

[0088] See also Figure 3 , take the leading edge of the 6dB pulse EPSV as the true pulse edge ALE.

[0089] Since there is a relatively large possibility that the 6dB pulse EPSV will be split when the response pulse is interleaved, in order to minimize the loss of pulse edge judgment, the width of the background noise pulse NPSV is judged here to determine whether there are (two or more) interleaved pulses, that is: starting from the trailing edge of the 6dB pulse EPSV, when the width of the previous background noise pulse NPSV is ≥0.6us, it is considered that an interleaved pulse exists, and the true pulse edge PLE is obtained 0.45us in advance of the trailing edge of the 6dB pulse EPSV.

[0090] Step 32: extracting amplitude pseudo pulse edges respectively through the sum channel / difference channel;

[0091] See also Figure 4 When the noise floor pulse NPSV is valid, the subtle edge signal change at the top of the pulse is judged.

[0092] Normally, the consistency requirement for the top of the received pulse signal is ≤1dB. Based on this, 1.5dB is set as the judgment threshold for the subtle edge signal change at the pulse top (which can be adjusted according to the system characteristics). In addition, the judgment time threshold for the subtle edge signal change at the pulse top is set to 0.1us.

[0093] Step 33: extracting the phase difference pseudo pulse edge;

[0094] The secondary radar uses an array antenna to form a sum / difference receiving beam. Assume that target 1 is on the left side of the beam and target 2 is on the right side of the beam, as shown in the figure below.

[0095] Target 1 is on the left side of the antenna normal, such as Figure 5 (Left) shows the sum beam of the reply signal Relative to the difference beam The phase lag is 90°.

[0096] Target 2 is on the right side of the antenna normal, such as Figure 5 (Right) shows the sum beam of the reply signal Relative to the difference beam The phase leads by 90°.

[0097] When the response pulse is interleaved, the phase difference of the sum / difference channel of the pulse signal will change. Therefore, the pulse interleaving can be judged based on the rule that the sum / difference channel phase difference satisfies ±90°.

[0098] But in actual systems, Figure 6 As shown, the closer the target azimuth is to the beam center, the greater the deviation of the phase criterion, so the target adaptability screening can be performed based on the actual channel characteristics of the system.

[0099] like Figure 6As shown, since the deviation angle of the target azimuth from the beam center is correlated with the amplitude difference of the sum / difference channel, target adaptive screening can be performed by setting the amplitude difference threshold of the target signal and / or difference channel. When the target signal and / or difference amplitude difference is ≤20dB, it is suitable for extracting the phase pseudo pulse edge.

[0100] like Figure 7 As shown, the threshold can be set to 10°. At the position where the 6dB pulse EPSV is effective, when the sum / difference channel phase difference exceeds the range of 90±10°, the pulse is considered to be interleaved. In addition, the phase change threshold is set to 10° and the time threshold is set to 0.1us.

[0101] Step 34: Fusion the amplitude true pulse edge, the amplitude pseudo pulse edge, and the phase pseudo pulse edge.

[0102] In this embodiment, step 31 includes:

[0103] According to the EPSV and NPSV of the sum channel, the true pulse edge ALE of the sum channel is extracted; according to the EPSV and NPSV of the difference channel, the true pulse edge ALE of the difference channel is extracted; the leading edge of the 6dB pulse EPSV is taken as the true pulse leading edge ALE.

[0104] In this embodiment, step 32 includes:

[0105] Extract the pseudo pulse edge ELE of the sum channel according to the EPSV and NPSV of the sum channel and the sum channel amplitude;

[0106] According to the EPSV and NPSV of the difference channel and the amplitude of the difference channel, the pseudo pulse edge ELE of the difference channel is extracted;

[0107] In order to extract the change of the subtle edge signal at the top of the pulse and identify whether the current position is a valid pulse edge, it is also necessary to judge the pseudo pulse edge obtained by amplitude detection.

[0108] In this embodiment, the judgment condition of the pseudo pulse leading edge obtained by amplitude detection is:

[0109] There is no true pulse edge within ±0.1us of the current position;

[0110] There is no true pulse edge within 0.45us±0.1us from the current position;

[0111] Calculated backward from the current position, the background noise pulse width is ≥ 0.45us;

[0112] The judgment condition of the pseudo pulse trailing edge obtained by amplitude detection is:

[0113] There is no true pulse edge within 0.45us±0.1us from the current position;

[0114] Calculate forward from the current position, the background noise pulse width ≥ 0.45us;

[0115] According to the EPSV and NPSV of the sum channel, the amplitude of the sum channel, and the conditions for judging the pseudo pulse edge obtained by amplitude detection, the positions that conflict with the true pulse edges of the sum and difference channels are eliminated to obtain the pseudo pulse edge ELE of the sum channel;

[0116] According to the EPSV and NPSV of the difference channel, the amplitude of the difference channel, and the conditions for judging the pseudo pulse edge obtained by amplitude detection, the positions that conflict with the true pulse edges of the sum and difference channels are eliminated to obtain the pseudo pulse edge ELE of the difference channel.

[0117] In this embodiment, step 33 includes:

[0118] In order to extract the change of the phase difference of the sum / difference channel inside the pulse and identify whether the current position is a valid phase difference pulse edge, it is also necessary to judge the pseudo pulse edge obtained by phase difference detection.

[0119] In this embodiment, the condition for judging the pseudo pulse leading edge obtained by phase difference detection is:

[0120] There is no true pulse edge within ±0.1us of the current position; wherein the true pulse edge includes the true pulse edge ALE of the sum channel, the true pulse edge PLE of the sum channel, the true pulse edge ALE of the difference channel, and the true pulse edge PLE of the difference channel;

[0121] There is no true pulse edge within 0.45us±0.1us from the current position;

[0122] Calculated backward from the current position, the background noise pulse width is ≥ 0.45us;

[0123] The conditions for judging the trailing edge of the pseudo pulse obtained by phase difference detection are:

[0124] There is no true pulse edge within 0.45us±0.1us from the current position;

[0125] Calculate forward from the current position, the background noise pulse width ≥ 0.45us;

[0126] See also Figure 8 , a phase pseudo pulse edge PELE is generated by judging the position of the pseudo pulse leading edge obtained by phase difference detection or the position 0.45us in advance of the pseudo pulse trailing edge.

[0127] In this embodiment, step 34 includes:

[0128] The true pulse edge ALE of the sum channel, the true pulse edge PLE of the sum channel, the false pulse edge ELE of the sum channel, the true pulse edge ALE of the difference channel, the true pulse edge PLE of the difference channel, the false pulse edge ELE of the difference channel, and the false pulse edge PELE of the phase difference are integrated. Taking the true pulse edge detected first as the reference, the false pulse edge whose position overlaps within ±0.1us and the true pulse edge within 0.1us after the current edge position are eliminated to obtain the final pulse edge PSVEDGE output.

[0129] This method uses the amplitude of the sum / difference dual channel as the basis for pulse extraction. Since the probability of the amplitude of the sum / difference channel being superimposed or offset at the same time is small in the case of pulse interleaving, it can effectively improve the probability of pulse extraction.

[0130] This method uses the change of the phase difference of the sum / difference dual channels to determine the position of pulse interleaving and extract the pseudo edge of the pulse. Since there is a stable phase difference between the sum / difference two channel signals of the pulse without interleaving within the effective beam width, the probability of extracting the interleaved pulse can be effectively improved.

[0131] The method adopts two levels of amplitude thresholds to judge the pulse edge, that is, adopts a 6dB threshold to judge the pulse true edge and adopts a 1.5dB threshold to judge the pulse false edge, which can effectively improve the extraction probability of the interleaved pulse.

[0132] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A secondary radar response pulse extraction method based on sum and difference dual channel amplitude and phase characteristics, characterized in that: include: Step 1: The air traffic control secondary radar uses the sum / difference beam to receive the reply signal; Step 2: Extract the response pulse PSV through the 6dB threshold and the noise floor threshold respectively; Step 3: Use threshold judgment to extract the response signal pulse PSV, and use the background noise threshold to extract the effective pulse; The step 3 comprises: Step 31: extracting the amplitude true pulse edge through the sum channel / difference channel respectively; Step 32: extracting amplitude pseudo pulse edges respectively through the sum channel / difference channel; Step 33: extracting the phase difference pseudo pulse edge; Step 34: Fusion of amplitude true pulse edge, amplitude pseudo pulse edge, and phase difference pseudo pulse edge; The step 31 comprises: According to the EPSV and NPSV of the sum channel, the true pulse edge ALE of the sum channel is extracted; according to the EPSV and NPSV of the difference channel, the true pulse edge ALE of the difference channel is extracted; the leading edge of the 6dB pulse EPSV is taken as the true pulse leading edge ALE; The existence of two or more interleaved pulses is determined by judging the width of the background noise pulse NPSV, that is, starting from the trailing edge of the 6dB pulse EPSV, when the width of the background noise pulse NPSV is greater than or equal to 0.6us, it is considered that there is an interleaved pulse, and the amplitude true pulse edge PLE is obtained 0.45us ahead of the trailing edge of the 6dB pulse EPSV; The step 32 comprises: Extract the pseudo pulse edge ELE of the sum channel according to the EPSV and NPSV of the sum channel and the sum channel amplitude; According to the EPSV and NPSV of the difference channel and the amplitude of the difference channel, the pseudo pulse edge ELE of the difference channel is extracted; In order to extract the change of the subtle edge signal at the top of the pulse, it is also necessary to judge the pseudo pulse edge obtained by amplitude detection to identify whether the current position is a valid pulse edge; 1.5dB is set as the judgment threshold of the subtle edge signal change at the top of the pulse, and the judgment threshold can be adjusted according to the system characteristics. In addition, the judgment time threshold of the subtle edge signal change at the top of the pulse is set to 0.1us; The step 33 comprises: In order to extract the change of the phase difference of the sum / difference channel inside the pulse, it is also necessary to identify whether the current position is a valid phase difference pulse edge and to judge the pseudo pulse edge obtained by the phase difference detection; The step 34 comprises: The true pulse edge ALE of the sum channel, the true pulse edge PLE of the sum channel, the false pulse edge ELE of the sum channel, the true pulse edge ALE of the difference channel, the true pulse edge PLE of the difference channel, the false pulse edge ELE of the difference channel, and the false pulse edge PELE of the phase difference are integrated. Taking the true pulse edge detected first as the reference, the false pulse edge whose position overlaps within ±0.1us and the true pulse edge within 0.1us after the current edge position are eliminated to obtain the final pulse edge PSVEDGE output.

2. The method according to claim 1, characterized in that In step 2: Extract the response pulse PSV through the 6dB threshold, including: The starting position where the signal amplitude changes by more than 6dB relative to the pulse top amplitude is the true position of the pulse front and back edges. The 6dB threshold judgment method is used to extract the response signal pulse PSV, so as to facilitate the subsequent accurate extraction of the true edge of the pulse. Extract the response pulse PSV through the noise floor threshold, including: The amplitude change of the top of the interleaved pulse may exceed the edge judgment threshold of 6dB. When the signal is greater than the noise floor threshold, the noise floor pulse signal NPSV is extracted.

3. The method according to claim 2, characterized in that The extracting of the response pulse PSV by the 6dB threshold also includes: When the signal amplitude is greater than the noise floor threshold and meets the rising and falling edge judgment conditions of the 6dB threshold, the 6dB pulse signal EPSV is extracted.

4. The method according to claim 1, characterized in that: The judgment condition of the pseudo pulse leading edge obtained by amplitude detection is: There is no true pulse edge within ±0.1us of the current position; There is no true pulse edge within 0.45us±0.1us from the current position; Calculated backward from the current position, the background noise pulse width is ≥ 0.45us; The judgment condition of the pseudo pulse trailing edge obtained by amplitude detection is: There is no true pulse edge within 0.45us±0.1us from the current position; Calculate forward from the current position, the background noise pulse width ≥ 0.45us; According to the EPSV and NPSV of the sum channel, the amplitude of the sum channel, and the conditions for judging the pseudo pulse edge obtained by amplitude detection, the positions that conflict with the true pulse edges of the sum and difference channels are eliminated to obtain the pseudo pulse edge ELE of the sum channel; According to the EPSV and NPSV of the difference channel, the amplitude of the difference channel, and the conditions for judging the pseudo pulse edge obtained by amplitude detection, the positions that conflict with the true pulse edges of the sum and difference channels are eliminated to obtain the pseudo pulse edge ELE of the difference channel.

5. The method according to claim 1, characterized in that The conditions for judging the leading edge of the pseudo pulse obtained by phase difference detection are: There is no true pulse edge within ±0.1us of the current position; wherein the true pulse edge includes the true pulse edge ALE of the sum channel, the true pulse edge PLE of the sum channel, the true pulse edge ALE of the difference channel, and the true pulse edge PLE of the difference channel; There is no true pulse edge within 0.45us±0.1us from the current position; Calculated backward from the current position, the background noise pulse width is ≥ 0.45us; The conditions for judging the trailing edge of the pseudo pulse obtained by phase difference detection are: There is no true pulse edge within 0.45us±0.1us from the current position; Calculate forward from the current position, the background noise pulse width ≥ 0.45us; A phase pseudo pulse edge PELE is generated at the position of the pseudo pulse leading edge obtained by judging the pseudo pulse edge obtained by phase difference detection or at the position 0.45 us in advance of the pseudo pulse trailing edge.

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