阅读说明：本技术 一种脉冲式无线电高度表视频目标处理电路 (Pulse type radio altimeter video target processing circuit ) 是由 李良刚 张静 霍志 刘曦 孙益周 黄鑫 于 2019-11-19 设计创作，主要内容包括：本发明公开了一种脉冲式无线电高度表视频目标处理电路,包括门限控制器(1)、目标整形器(2)、目标检测器(3)、分裂波门产生器(4)、鉴时器(5)、主波门产生器(6)、调整脉冲产生器(7)、高度计算器(8)、定时器(9)、时间间隔器(10)和恒温晶振(11),门限控制器(1)和目标整形器(2)实现目标判别和前沿提取,目标检测器(3)和主波门产生器(6)用于目标检测,分裂波门产生器(4)、鉴时器(5)和调整脉冲产生器(7)实现分裂波门误差检测；高度计算器(8)、定时器(8)、时间间隔器(10)、恒温晶振(11)用于闭环解算和输出150MHz高稳定频率；实现了对回波视频目标判别、闭环跟踪及高精度处理。(The invention discloses a video target processing circuit of a pulse type radio altimeter, which comprises a threshold controller (1), a target shaper (2), a target detector (3), a split wave gate generator (4), a time discriminator (5), a main wave gate generator (6), an adjusting pulse generator (7), a height calculator (8), a timer (9), a time spacer (10) and a constant temperature crystal oscillator (11), wherein the threshold controller (1) and the target shaper (2) realize target discrimination and leading edge extraction, the target detector (3) and the main wave gate generator (6) are used for target detection, and the split wave gate generator (4), the time discriminator (5) and the adjusting pulse generator (7) realize split wave gate error detection; the height calculator (8), the timer (8), the time spacer (10) and the constant temperature crystal oscillator (11) are used for closed-loop resolving and outputting 150MHz high stable frequency; the method realizes discrimination, closed-loop tracking and high-precision processing of the echo video target.)

1. An impulse type radio altimeter video target processing circuit is characterized in that: the device comprises a threshold controller (1), a target shaper (2), a target detector (3), a split wave gate generator (4), a time discriminator (5), a main wave gate generator (6), an adjusting pulse generator (7), a height calculator (8), a timer (9), a time spacer (10) and a constant temperature crystal oscillator (11), wherein the threshold controller (1) is used for carrying out threshold detection on a video target echo to generate an effective target and outputting the effective target to the target shaper (2); the target shaper (2) shapes an effective target and then changes the effective target into a shaped target which is output to the target detector (3) and the time discriminator (5); the target detector (3) receives the main gate sent by the main gate generator (6), if the real existence of the target is judged within the effective time of the main gate, a tracking high level is output to the error pulse generator (7) and the height calculator (8), otherwise, a tracking low level is output to the error pulse generator (7) and the height calculator (8); the split wave gate generator (4) forms a front wave gate and a back wave gate by taking the front edge of the delay synchronous pulse sent by the height calculator (8) as a reference and outputs the front wave gate and the back wave gate to the time discriminator (5); the time discriminator (5) discriminates the time ratio of the shaping target in the front wave gate and the rear wave gate, and generates error voltage with polarity to be sent to the adjusting pulse generator (7); the main gate generator (6) forms a main gate by taking the leading edge of the delay synchronous pulse sent by the time spacer (10) as a reference and outputs the main gate to the target detector (3); the adjusting pulse generator (7) converts the polarity and the voltage value of the error voltage sent by the time discriminator (5) into a forward or backward error adjusting pulse and sends the forward or backward error adjusting pulse to the height calculator (8); when the height calculator (8) receives the tracking high level output by the target detector (3), the forward or backward error adjusting pulse input by the adjusting pulse generator (7) is subjected to counting reduction or counting addition to obtain effective height output, and one path of height output is output and sent to a system for data processing; outputting the other path of 2 times height output to a time spacer (10); the timer (9) converts a frequency signal sent by the constant-temperature crystal oscillator (11) into a periodic height starting pulse, and sends the periodic height starting pulse to the height calculator (8) and the time spacer (10) to be used as a periodic synchronization and counting reference; the time spacer (10) takes 2 times of height output sent by the height calculator (8) as a decrement, takes a height starting pulse generated by the timer (9) as a reference, and counts down the 2 times of height output according to a frequency signal provided by the constant temperature crystal oscillator (11), and when the value of the counter is zero, a delay synchronous pulse is sent to the split wave gate generator (4) and the main wave gate generator (6); the constant temperature crystal oscillator (11) provides frequency signals for the time spacer (10) and the timer (9).

2. The pulsed radio altimeter video target processing circuit of claim 1, wherein: the maximum frequency of the forward or backward error adjusting pulse sent by the adjusting pulse generator (7) corresponds to the effective tracking bandwidth of the video target.

3. The pulsed radio altimeter video target processing circuit of claim 2, wherein: the constant temperature crystal oscillator (11) provides 150MHz frequency signals for the time spacer (10) and the timer (9), and the corresponding resolution of the 150MHz frequency signals is 0.5 meter.

Technical Field

The invention relates to a video target processing circuit of an impulse type radio altimeter.

Background

The impulse type radio altimeter ranging principle is that a target distance is calculated according to a ranging formula H = C/2 t. Wherein H is height; c is light speed 300m/us, t is target delay time, and the video target processing circuit is used for judging whether the video target is effective or not and continuously calculating the delay time t of the effective video target. The simplest processing method of the impulse type video object processing circuit is that a timer sends a START signal to a time interval measuring unit and the START signal is used as a timing starting signal of the timer of the time interval measuring unit, when a video object arrives, the timer generates a STOP signal to the time interval measuring unit and the STOP signal is used as a timing end signal of the timer of the time interval measuring unit, and therefore the delay time t of the video object is obtained. The circuit cannot form closed-loop tracking on the video target, the tracking bandwidth cannot be limited to a value necessary for tracking, and the circuit is easily interfered by a false target. In the current stage, a plurality of radar video target processing systems adopt 3-5 samples near a video echo pulse by using a sampling circuit, then compare the amplitudes of a front wave gate and a rear wave gate with the amplitudes of the front half and the rear half of the video echo pulse samples to detect a distance error, then adjust the position of the distance wave gate through the distance error, and correct a distance reading to close a distance tracking loop. The processing method adopts amplitude comparison, dynamic fluctuation of video target echoes caused by target characteristics will certainly have great influence on processing precision, and the low-end precision of a radio altimeter system is about 1 meter generally, so the amplitude comparison method is not suitable for a high-precision radio altimeter system.

Disclosure of Invention

The invention aims to provide a pulse type radio altimeter video target processing circuit which can distinguish, track in a closed loop and process with high precision an echo video target. In order to solve the above technical problem, the present invention provides a video target processing circuit for impulse type radio altimeter, which is characterized in that: the device comprises a threshold controller 1, a target shaper 2, a target detector 3, a split wave gate generator 4, a time discriminator 5, a main wave gate generator 6, an adjusting pulse generator 7, a height calculator 8, a timer 9, a time spacer 10 and a constant temperature crystal oscillator 11, wherein the threshold controller 1 is used for carrying out threshold detection on an echo video target, generating an effective target and outputting the effective target to the target shaper 2; the target shaper 2 shapes the effective target and then turns the effective target into a shaped target to be output to the target detector 3 and the time discriminator 5; the target detector 3 receives the main gate sent by the main gate generator 6, and if the real existence of the target is judged within the effective time of the main gate, a tracking high level is output to the error pulse generator 7 and the height calculator 8, otherwise a tracking low level is output to the error pulse generator 7 and the height calculator 8; the splitting wave gate generator 4 forms a front wave gate and a back wave gate by taking the front edge of the delay synchronous pulse sent by the height calculator 8 as a reference and outputs the front wave gate and the back wave gate to the time discriminator 5; the time discriminator 5 discriminates the time ratio of the shape object in the front wave gate and the back wave gate, and generates error voltage with polarity to be sent to the adjusting pulse generator 7; the main gate generator 6 forms a main gate based on the leading edge of the delayed sync pulse sent from the time spacer 10 and outputs the main gate to the target detector 3; the adjusting pulse generator 7 converts the polarity and the voltage value of the error voltage sent by the time discriminator 5 into a forward or backward error adjusting pulse and sends the forward or backward error adjusting pulse to the height calculator 8; when the height calculator 8 receives the tracking high level output by the target detector 3, the forward or backward error adjusting pulse input by the adjusting pulse generator 7 is counted down or counted up to obtain effective height output, and one path of height output is output and sent to the system for data processing; outputting the other 2 times of height output to a time spacer 10; the timer 9 converts the frequency signal sent by the constant temperature crystal oscillator 11 into a periodic height starting pulse, and sends the periodic height starting pulse to the height calculator 8 and the time spacer 10 to be used as a periodic synchronization and counting reference; the time spacer 10 takes 2 times of height output sent by the height calculator 8 as a decrement, takes the height starting pulse generated by the timer 9 as a reference, counts down the 2 times of height output according to a frequency signal provided by the constant temperature crystal oscillator 11, and sends out delay synchronization pulse to the split wave gate generator 4 and the main wave gate generator 6 when the value of the counter is zero; the constant temperature crystal oscillator 11 provides frequency signals for the time spacer 10 and the timer 9.

Further, the maximum frequency of the forward or backward error adjustment pulse sent by the adjustment pulse generator 7 corresponds to the effective tracking bandwidth of the video target.

Further, the constant temperature crystal oscillator 11 provides 150MHz frequency signals for the time spacer 10 and the timer 9, and the resolution of the 150MHz frequency signals is 0.5 meter.

The pulse type radio altimeter video target processing circuit has the following positive effects that the high-precision processing of the pulse type radio altimeter video target echo is realized by utilizing a target leading edge extraction technology, namely a target leading edge shaping principle, a target detection technology, namely a sliding window detection principle, a target tracking technology, namely a split wave gate tracking principle, and a delay measurement technology, namely a high-precision time interval measurement principle. The threshold controller 1 and the target shaper 2 realize target discrimination and leading edge extraction to finish noise isolation and target effectiveness judgment, and shape and standardize the target to isolate the influence of target echo characteristics on the distance measurement error. The target detector 3 and the main wave gate generator 6 are used for target detection, the number of effective targets in the main wave gate adopts 8/32 through a sliding window detection principle, namely 8 effective targets exist in 32 counting main wave gates, and target detection is completed, so that target discovery probability is improved, and tracking false alarm rate is reduced. The split wave gate generator 4, the time discriminator 5 and the adjusting pulse generator 7 realize the error detection and the adjusting output of the split wave gate. When the target detector 3 outputs a tracking high level, the time discriminator 5 is switched on, if the front wave gate is divided into shaping target time which is larger than the rear wave gate, the error voltage sent by the time discriminator 5 is a positive value, the adjusting pulse generator 7 sends out a count-down error adjusting pulse, controls the height calculator 8 to count down, and enables the delay synchronous pulse output by the time spacer 10 to move forward; similarly, if the rear gate is divided into a plurality of shaped target time periods larger than the front gate, the error voltage sent by the time detector 5 is a negative value, the adjustment pulse generator 7 sends an error adjustment pulse for adding the count, the height calculator 8 is controlled to add the count, the delay synchronization pulse output by the time spacer 10 moves backward, and when the target detector 3 outputs a tracking low level, the time detector 5 is turned off. The height calculator 8, the timer 9, the time spacer 10 and the constant temperature crystal oscillator 11 are used for realizing the closed-loop resolving function of the video target. When the target detector 3 outputs a "tracking" low level, the height calculator 8 does not respond to the error adjustment pulse, but takes the height start pulse generated by the timer 9 as a calculation input, and accumulates 1 every one height start pulse, and counts cyclically from the span minimum to the maximum. The time spacer 10 extracts 2 times height output as a subtracted number by taking the height initial pulse as a reference, performs subtraction counting by using a high-stability frequency signal sent by a constant-temperature crystal oscillator 11, and sends delay synchronous pulses to the main gate generator 6 and the split-wave gate generator 4 when the counter value is zero; similarly, when the target detector 3 outputs a tracking high level, the height calculator 8 takes the error adjusting pulse generated by the adjusting pulse generator 7 as a calculation input, and performs count down or count up according to the forward or backward error adjusting pulse, so as to control the delay synchronous pulse output by the time spacer 10 to move forward or backward, complete the tracking closed loop of the target, and obtain an effective height output; the constant temperature crystal oscillator 11 outputs 150MHz high stable frequency signal, i.e. counting frequency pulse signal, and the height output corresponding relation is that the height data 1LSB is 0.5 m.

Drawings

Fig. 1 is a schematic block diagram of an impulse radio altimeter video target processing circuit of the present invention.

In the figure: 1. the device comprises a threshold controller, 2, a target shaper, 3, a target detector, 4, a split wave gate generator, 5, a time discriminator, 6, a main wave gate generator, 7, an adjusting pulse generator, 8, a height calculator, 9, a timer, 10, a time spacer and 11, a constant temperature crystal oscillator.

Detailed Description

Fig. 1 shows a schematic block diagram of an impulse radio altimeter video target processing circuit of the present invention. The invention discloses a video target processing circuit of an impulse type radio altimeter, which is characterized in that: the device comprises a threshold controller 1, a target shaper 2, a target detector 3, a split wave gate generator 4, a time discriminator 5, a main wave gate generator 6, an adjusting pulse generator 7, a height calculator 8, a timer 9, a time spacer 10 and a constant temperature crystal oscillator 11.

The threshold controller 1 is composed of a high-speed comparator and is used for carrying out threshold detection on the echo video target, and when the leading edge of an echo signal exceeds a preset threshold of the high-speed comparator, the high-speed comparator triggers to generate a rectangular TTL pulse as an effective target and outputs the rectangular TTL pulse to the target shaper 2.

The target shaper 2 is composed of a leading edge triggering monostable circuit and is used for receiving the effective target output by the threshold controller 1, and the effective target is converted into a shaped target with the leading edge consistent with the effective target and fixed pulse width and amplitude through the leading edge triggering monostable circuit, so that the tracking error caused by the change of the pulse width and the amplitude of the effective target is isolated. After the effective target is changed into a shaped target, the shaped target is output to the target detector 3 and the time discriminator 5.

The target detector 3 is composed of a digital sliding window counting circuit, the target detector 3 receives a main gate sent by a main gate generator 6, a denominator counter of the sliding window counting circuit counts and accumulates 1 for each main gate, meanwhile, a numerator counter of the sliding window counting circuit counts and accumulates 1 for a whole shaped target within the effective time of the main gate, the denominator counter and the numerator counter of the sliding window counting circuit both adopt a first-in first-out principle, when 8/32 is met, namely 8 effective targets exist in 32 counting main gates, if the real existence of the target is judged, a tracking high level is output to an error pulse generator 7 and a height calculator 8, otherwise, a tracking low level is output to the error pulse generator 7 and the height calculator 8;

the splitting wave gate generator 4 is composed of a leading edge triggering monostable circuit and a trailing edge triggering monostable circuit, a front wave gate is formed by the leading edge triggering monostable circuit with the leading edge of a delay synchronous pulse sent by the height calculator 8 as a reference, a rear wave gate is formed by the front wave gate through the trailing edge triggering monostable circuit, the pulse width and the amplitude of the front wave gate and the pulse width of the rear wave gate are the same, the trailing edge of the front wave gate coincides with the leading edge of the rear wave gate, and the front wave gate and the rear wave gate are output to the time discriminator 5.

The time discriminator 5 is composed of a high-speed switch triode and is used for discriminating the time ratio of the shaping target in a front wave gate and a rear wave gate, and the ratio pulse formed by the front wave gate and the shaping target forms an error voltage which is a positive value through a positive-pressure high-speed switch triode; the proportion pulse formed by the back wave gate and the shaping target forms an error voltage with a negative value through a negative voltage high-speed switching three-stage tube, and the error voltage with polarity generated by the time discriminator 5 is sent to the adjusting pulse generator 7.

The main gate generator 6 is composed of a leading edge trigger monostable circuit, and forms a main gate by the leading edge trigger monostable circuit according to the leading edge of the sent delay synchronization pulse as a reference, the width of the main gate is equal to the sum of the widths of the front gate and the rear gate, and the main gate and the rear gate are output to the target detector 3 for selecting and distinguishing the target.

The adjusting pulse generator 7 is composed of a second-order V/F (voltage/frequency) conversion circuit, according to the polarity and voltage value of the time error voltage of the front wave gate and the back wave gate sent by the time detector 5, when the output of the target detector 3 is in high level, the second-order V/F conversion is switched on, the error voltage of positive and negative polarity is converted into forward or backward error adjusting pulse through the second-order V/F conversion circuit, and the error adjusting pulse is sent to the height calculator 8.

The maximum frequency of the error adjustment pulse corresponds to the effective tracking bandwidth of the video target.

The height calculator 8 is composed of a high-speed up/down counting circuit, when the target detector 3 outputs a tracking low level, the high-speed up/down counting circuit does not respond to the error adjusting pulse of the adjusting pulse generator 7, but takes the height starting pulse generated by the timer 9 as an up counting input, and counts circularly from the minimum value of the measuring range to the maximum value by accumulating 1 every height starting pulse. When the target detector 3 outputs a tracking high level, the high-speed up/down counting circuit takes the error adjusting pulse generated by the adjusting pulse generator 7 as a calculation input, and performs down counting or up counting according to the forward or backward error adjusting pulse, thereby completing a tracking closed loop of the target and obtaining effective height output. One path of output of the height calculator 8 is height data output and sent to a system for data processing; the other is 2 times the height output representing 2t in the formula, sent to the time spacer 10.

The timer 9 is composed of a high-speed accumulation circuit and a leading edge triggering monostable circuit, 150MHz sent by a constant temperature crystal oscillator 11 is used as a frequency signal, the timer 9 is provided with two preset values of an accumulation median value and an accumulation maximum value, when the accumulation value of the accumulation circuit is smaller than the accumulation median value, the low level is output, when the accumulation value of the accumulation circuit is larger than the accumulation median value, the high level is output, when the accumulation value of the accumulation circuit is equal to the accumulation maximum value, the accumulator is cleared to zero, so that a periodic pulse is generated, the periodic pulse is converted into a periodic height starting pulse narrow pulse through the leading edge triggering monostable circuit, and the periodic pulse is sent to a height calculator 8 and a time spacer 10 to.

The time spacer 10 is composed of a high-speed presettable countdown circuit, 2 times of height output sent by the height calculator 8 is extracted in each calculation period and is used as a decremented number, the height initial pulse generated by the timer 9 is used as a reference, the 2 times of height output is counted down according to the 150MHz frequency provided by the constant temperature crystal oscillator 11, and when the value of the counter is zero, delay synchronous pulses are sent to the splitting wave gate generator 4 and the main wave gate generator 6.

The constant temperature crystal oscillator 11 provides frequency signals for the time spacer 10 and the timer 9. In order to ensure the distance measurement precision, a 150MHz constant temperature crystal oscillator is used as a high-stability frequency source of the time spacer 10 and the timer 9, and the corresponding resolution of 150MHz is 0.5 m.

The video target processing circuit of the pulse type radio altimeter has two working modes: a tracking mode and a search mode. In the tracking mode: the video target passes through threshold discrimination and target detection, the tracking signal is high level, so that the adjusting pulse generator 7 is connected with the height calculator 8, the height starting pulse is disconnected with the height calculator 8, the error voltage formed by the front and rear wave gates and the shaping target automatically adjusts the height output and the target delay, and the closed loop tracking of the video target is formed. In the search mode: the video target does not pass the threshold judgment or does not meet the target detection, the tracking signal is in low level, so that the adjusting pulse generator 7 is disconnected with the height calculator 8, the height starting pulse is connected with the height calculator 8, the cyclic counting is carried out in the height measuring range, namely the height output in each period is accumulated to be 1, and the target delay is increased by a time interval.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications and equivalent variations of the above embodiments according to the technical spirit of the present invention are included in the scope of the present invention.