RU2018875C1 - Device for measuring seaway characteristic - Google Patents

Abstract

FIELD: oceanography for measuring seaway characteristics. SUBSTANCE: device for measuring seaway characteristics has transceiver 1, synchronizer 2, envelope detector 3, pulse generator 4, electronic switch 5, delay line 6, AND gate 7, trigger 11, analog-to digital converter 9, electronic switch 10, trigger 11, frequency divider 12, reference point-driving unit 14, registers 15,16, programmable counter 17, digit comparators 18,19, electronic key 20, OR gates 21,22, trigger 23, clock- pulse generator 24, trigger 25, counter 26, recording unit 27. EFFECT: increased measurement accuracy. 2 dwg

Description

 The invention relates to oceanography and is intended for non-contact measurements of surface wave characteristics by radar means.

 A device is known, which includes a pulsed radar with a circular viewing indicator (PPI) and a camera (Dremlyuk V.V. On the determination of some elements of sea waves using a radar. Proceedings of the Arctic and Antarctic Research Institute, 1961, v. 210, no. 1, p. 135-138). The surface situation is displayed on the PPI screen. Images on the PPI are photographed and, based on the analysis of these images, the characteristics of surface waves are determined. The area of echoes from the sea surface on the IRF has an oval shape, with most of it located on the windward side. The general direction of wave propagation is determined by the radar dial in the photographs. To determine the wavelength, the distance between the wave crests is measured directly on the radar screen photograph taking into account the image scale. The wave period is determined by fixing the period of time during which two consecutive pulses from the leeward slopes of the waves pass through the same point on the screen.

 However, such a device can only be implemented on the basis of a high-resolution radar providing a separate image on the surface-wave infrared spectrometer, and cannot be realized using a low-resolution radar. In addition, the measurement result and its accuracy largely depend on the qualifications and experience of the operator.

 This drawback is eliminated by using a device for measuring the characteristics of sea waves, comprising a pulse radar transceiver, a synchronizer, a strobe pulse generating unit, an envelope detector, a normalizer, an integrator and a recorder connected in series, in which the synchronizer output is connected to the corresponding inputs of the transceiver and the strobe forming unit, the envelope detector input - with the output of the transceiver, and the output of the block forming the strobe pulse s - with the control input of the envelope detector, which, by the set of essential features, is closest to the proposed one and is taken as a prototype.

 In this device, the video signal from the output of the transceiver enters the envelope detector, which stores the amplitude value of the signal only at the moments when the strobe pulses arrive at its control output. The block generating strobe pulses is synchronized by pulses from the synchronizer. The repetition rate of strobe pulses corresponds to the repetition rate of probing pulses, and the delay time of the former relative to the latter determines the distance from the radar to the gated portion of the sea surface. At the output of the envelope detector, the envelope of the video pulses received from a fixed range is allocated. This voltage is supplied to the normalizer, which generates pulses normalized in amplitude and duration at the moments of crossing the envelope of the average level. As a result of integration of normalized pulses for a certain time interval, the output of the integrator produces a voltage proportional to the average frequency of fluctuations of the envelope of the reflected signals, which is measured by a recording device and whose value is related to the height of the surface waves. This device allows you to measure the following characteristics of the waves: the height of the waves; general direction of wave propagation; group structure of waves.

 The general direction of wave propagation is determined by analyzing the azimuthal dependence of the average frequency of envelope fluctuations obtained by rotating the radar antenna, which has a fairly narrow radiation pattern in the horizontal plane. The maximum value of the average frequency of envelope fluctuations is obtained upon irradiation along the general direction of wave propagation, and the minimum upon irradiation along the wave crests.

 The wave height is found by half the maximum and minimum values of the average frequency of envelope fluctuations in its azimuthal dependence. The group structure of sea waves is investigated by analyzing measurements over time of the measured values of the height of the waves.

 When using this device, it is necessary to ensure that the reflected signals are not limited in amplitude in the receiving path of the radar, which is recommended by setting the corresponding gain of the amplifier (gain knob) and temporary automatic gain control (using the knobs on the radar control panel) before measuring it ( handle "Varu") and select the distance to the gated section of the sea surface. However, in a number of ship navigation radars (for example, such as Mius, Kivach, Naiad), these handles are absent on the radar control panel, and it is impossible to change these coefficients during radar operation. In addition, changes in the level of radar reflections from the gated portion of the sea surface, due to the group structure of waves and rocking of the vessel, can reach 20 dB or more. In this case, it is not possible to ensure that the reflected signals are not limited in amplitude even if the above coefficients can be adjusted, since the dynamic range of the receiving paths of shipborne navigation radars does not exceed 20 dB. Thus, in most real cases, it is not possible to ensure that there are no restrictions on the signals reflected from the gated portion of the sea surface in the receiving path of the ship's navigation radar. If there are limitations, the average frequency of envelope fluctuations, determined by the number of intersections of the average level envelope for a certain time interval, will be less than the true value, which leads to an underestimation of the results of measurements of the height of sea waves, i.e. to the appearance of a systematic measurement error. As a result, the presence of restrictions on the amplitude of the reflected signals in the receiving path of the radar leads to an increase in the total error of measurements of wave height.

 The aim of the invention is to improve the accuracy of measuring the height of surface waves.

 This is achieved by the fact that a delay line, a pulse generator, an electronic key, a pulse number counter, a clock pulse generator are introduced into the device containing the pulse radar transceiver, the synchronization input of which is connected to the output of the synchronizer, the recorder and the envelope detector, the input of which is connected to the output of the transceiver , four triggers, two electronic switches, three OR elements, AND element, programmable counter, frequency divider, initial start-up block, analog-to-digital converter (ADC), two reg storage unit and two digital comparators, the first trigger, the And element, the delay line, the first electronic switch and the pulse generator are connected in series, the trigger trigger input is connected to the synchronizer output, the pulse generator output is connected to the control input of the envelope detector, the transceiver output is connected to the second the input of the And element, whose output is connected to the second input of the first electronic switch and the reset input of the first trigger, the ADC input is connected to the envelope detector output, and the ADC output is connected to the reg inputs storage channels and to the second inputs (B) of each comparator, the first inputs of which are connected to the outputs of the corresponding storage register, a clock pulse generator, an electronic key, a programmable counter, the first OR element and the second trigger (installation input) are connected in series, the output of the second trigger is connected to control inputs of electronic switches, the second input of the first element OR - with the output of the initial start-up block, the output of the first electronic switch is connected to the start-up input of the ADC, the output of the ADC "End of conversion "- with the input of the second electronic switch, the first output of which is connected to the control input of the second comparator, and the second output - to the control input of the second storage register directly and through the frequency divider - to the reset inputs of the second trigger and counters, output A> B of the first digital comparator connected to the installation input of the fourth trigger and the first input of the second OR element, the second input of which is connected to the output A <B of the first digital comparator and the reset input of the fourth trigger, and the output to the control the first storage register, the fourth trigger (setup input), the pulse counter and the recorder are connected in series, the output A> B of the second digital comparator is connected to the control input of the first digital comparator and to the reset input of the third trigger, and the outputs A = B and A <B through the third OR element - to the installation input of the third trigger, the output of which is connected to the control input of the electronic key, the output of the programmable counter is connected to the control input of the recorder.

 Figure 1 shows the structural electrical diagram of the device; figure 2 and 3 - plot stresses.

 The device comprises a pulse radar transceiver 1, a synchronizer 2, an envelope detector 3, a pulse generator 4, a first electronic switch 5, a delay line 6, an element 7, a first trigger 8, an analog-to-digital converter 9, a second electronic switch 10, a second trigger 11, a divider 12 frequencies, first OR element 13, initial start block 14, first storage register 15, second storage register 16, programmable counter 17, first digital comparator 18, second digital comparator 19, electronic key 20, second OR 21, third AND element LI 22, the third trigger 23, the clock generator 24, the fourth trigger 25, the counter 26 of the number of pulses, the recorder 27.

 The synchronization input of the transceiver 1 is connected to the output of the synchronizer 2, and the output is to the input of the envelope detector 3, the first trigger 8, element 7, delay line 6, the first electronic switch 5 and the pulse generator 4 are connected in series, the installation input of the first trigger 8 is connected to the output synchronizer 2; the output of the 4 pulse generator is to the control input of the envelope detector 3, the output of the transceiver 1 is to the second input of the And 7 element, the output of which is connected to the second input of the first electronic switch 5 and the reset input of the first trigger 8, the ADC input 9 is connected to the output of the envelope detector 3, and the output of the ADC 9 is to the inputs of the storage registers 15 and 16 and to the second inputs (B) of each comparator 18 and 19, the first inputs (A) of which are connected to the output of the corresponding storage register, a clock pulse generator 34, an electronic key 20, a programmable counter 17 , P The first OR element 13 and the second trigger 11 (installation input) are connected in series, the output of the second trigger 11 is connected to the control inputs of the electronic switches 5 and 10, the second input of the first OR 13 element is connected to the output of the initial start-up unit 14, the output of the first electronic switch 5 is connected to ADC 9 start-up input, ADC 9 “End of conversion” output - with the input of the second electronic switch 10, the first output of which is connected to the control input of the second comparator 19, and the second output - to the control input of the second storage register 16 actually and through the frequency divider 12, to the reset inputs of the second trigger 11 and counters 17 and 26, the output A> B of the first digital comparator 18 is connected to the installation input of the fourth trigger 25 and the first input of the second element OR 21, the second input of which is connected to the output A < In the first digital comparator 18 and the reset input of the fourth trigger 25, and the output is to the control input of the first storage register 15, the fourth trigger 25 (setup input), the pulse number counter 26 and the recorder 27 are connected in series, the output A> B of the second digital comparator 19 is connected to the control input of the first comparator 18 and to the reset input of the third trigger 23, and the outputs A = B and A <B through the third element OR 22 - to the installation input of the third trigger 23, the output of which is connected to the control input of the electronic key 20, the programmable output the counter 17 is connected to the control input of the recorder 27.

When a clock pulse U ₂ (see Fig. ₂ ) arrives at the input of the first trigger 8, the signal U ₈ appears at the output of the last one, and it goes to one of the outputs of element 7. The video signal U ₁ from block 1 consists of two pulses, the first - a rectangular pulse, the duration of which τ _{and the} temporary position coincides with the duration and temporary position of the probe pulse, due to leakage of part of the transmitter signal into the receiving path, the second pulse of complex shape is formed by reflections from the sea surface. When the signal 7 is received at the second input of element And 7 from the transceiver 1, which is formed by seeping part of the energy into the receiving channel when a probe pulse is emitted, pulse U _{7 is} obtained at the output of the And 7 element, the temporary position of which corresponds to the temporary position of the probe pulse. The pulse from the output of the element U ₇ , arriving at the reset input of the first trigger 8, sets it to the zero position. The same pulse, delayed in the delay line 6 by the time t _back , determined by the distance to the studied section of the sea surface, or without delay, passing through the first switch 5, starts the pulse generator 4. The output of the first electronic switch 5 is connected to the first input (A) in the absence of a signal at the control input of the switch and switches to the second input (B) in the presence of a control signal. At the output of the pulse generator 4, strobe pulses U _{4 of the} required duration τ _p are generated _, the delay time of which relative to the probe pulses is t _ass or equal to zero.

The signal from the output of the transceiver 1 enters the input of the envelope detector 3, which stores the amplitude value of the signal only at the moments when the strobe pulses from the generator 4 arrive at its control input. At a zero delay of the strobe pulses, the signal at the output of the envelope detector 3 will correspond to the restriction level, since the signal , seeping into the receiving path of the radar during the emission of probing pulses, always ensures the achievement of the level of restriction. When the strobe pulse delay time t on the output _butt envelope detector 3 stands envelope pulses reflected from the surface of the selected sea area.

The signal from the output of the envelope detector 3 using the ADC 9, triggered by the trailing edge of the pulse from the output of the first electronic switch 5, is converted to digital form and fed to the inputs of the storage registers 15 and 16 and to the second inputs (B) of the digital comparators 18 and 19. The input of the second electronic switch 10 is connected to the first output (A) in the absence of a signal at its control input and switches to the second output (B) in the presence of a control signal at switches 5 and 10. In the second case, the signal at the output of the envelope detector 3, corresponding to I limit, after conversion to the ADC 9 by the signal "End of conversion" passing through the second electronic switch 10, is fixed in the second storage register 16. In the absence of a signal at the control input of the electronic switches 5 and 10, the signal at the output of the envelope detector 3, formed due to reflections from the studied section of the sea surface, is transmitted from the ADC 9 through the second electronic switch 10 to the control input of the second digital comparator 19 is compared in the digital comparator 19 with the level of restriction. When the reflected signal reaches the limit level (A = B or A <B), the signal of the corresponding output of the second digital comparator 19 through the third element OR 22 is fed to the installation input of the third trigger 23, the output of which appears. If the reflected signal reaches the level limit (A> B), the signal from output A> B of the second digital comparator 19 sets a zero state the third flip-flop 23. As a result, the output of the third flip-flop 23 formed by a pulse duration τ which corresponds to the interval limit _Res reflected signal (see U ₂₃ in figure 3).

 If there is no restriction of the reflected signal from the signal from the output A> B of the second digital comparator 19 in the first digital comparator 18, the reflected signal is compared with the signal obtained during the previous sounding and recorded in the first storage register 15, controlled by the signal from the output of the second element OR 21. If the reflected signal during the previous sensing was larger, then a signal appears at the output A>> B of the first digital trigger 25, sets the latter to a single state. In the case when the signal during the previous sounding was less, a signal appears at the output A <B of the first digital comparator 18, which sets the fourth trigger 25 to zero. As a result, with each fluctuation of the reflected signal, a pulse is generated at the output of the fourth trigger 25, the duration of which is approximately equal to half the time (current period) of the fluctuation.

Thus, the number of pulses at the output of the fourth trigger 25 corresponds to the number of fluctuations of the reflected signal. These pulses are considered the number of pulses the counter 26 and the count value N _MF is proportional to the average frequency of the fluctuations of the reflected signal corresponding to the average height of the waves, which is fixed registrar 27.

,, где τ_огрi - длительность i-го интервала ограничения сигнала; n - количество интервалов ограничений за время t_сч.The average frequency of fluctuations is determined by the number N _MF pulses counted by the counter 26 of the number of pulses according to the formula
f _{Woofer cp} = N / t _edited. The measurement time t _ISM = N _t T _t is determined by the number N _t and the period T _t clock pulses from the clock generator 24 through the electronic key 20 to the programmable counter 17. The required measurement time is set by setting the required value N _t in the programmable counter 17. If there are restrictions on the reflected signals, the electronic key 20 is closed by a signal supplied to its control input from the output of the third trigger 23, and clock pulses do not arrive at the input of the programmable counter 17 (see Fig. 3). Counting time (measurement cycle duration) t _mid is determined by the formula
t _mid = t _meas +

,, where τ _ogre is the duration of the ith signal restriction interval; n is the number of restriction intervals for the time t _sc .

 Thus, when determining the average frequency of fluctuations, the time intervals at which the signal is limited are excluded, which excludes the error in measuring the average frequency of fluctuations due to these limitations. Therefore, the accuracy of measuring the height of surface waves is increased.

After the programmable counter 17 counts N _t clock pulses, a signal appears at its output, which passes through the first element OR 13 to the installation input of the second trigger 11, the output of which appears a signal that controls electronic switches 5 and 10.

Т_n. Блок 14 начального запуска может быть выполнен, например, в виде генератора импульсов, работающего в ручном (ждущем) режиме запуска. Второй триггер 11 устанавливается в нулевое состояние сигналом с выхода делителя 12 частоты следования импульсов, на выход которого проходит только каждый второй импульс из поступающих на его вход. Этим обеспечивается гарантия того, что к моменту установки второго триггера 11 в нулевое состояние в регистр 16 хранения будет записан сигнал, соответствующий уровню ограничения. Сигнал с выхода делителя 12 частоты, кроме того, устанавливает в исходное (нулевое) состояние программируемый счетчик 17 и счетчик 26 числа импульсов. Регистратор 27 управляется сигналом с выхода программируемого счетчика 17. При поступлении сигнала с выхода программируемого счетчика 17 на управляющий вход регистратора 27 обеспечивается отображение на последнем результате измерения. Минимальная длительность импульсов на выходе программируемого счетчика 17, определяющая необходимое быстродействие регистратора 27, равна периоду Т_п повторения зондирующих импульсов.The next measurement cycle begins. The first start-up of the device (the beginning of the first measurement cycle) is carried out by supplying a signal from the initial start-up block 14 through the first OR 13 element to the installation input of the second trigger 11. Starting pulse duration τ ₁₄

T _n Block 14 initial start-up can be performed, for example, in the form of a pulse generator operating in a manual (standby) start mode. The second trigger 11 is set to zero by a signal from the output of the pulse-rate divider 12, to the output of which only every second pulse from the input to it passes. This ensures that by the time the second trigger 11 is set to zero, a signal corresponding to the limit level will be recorded in the storage register 16. The signal from the output of the frequency divider 12, in addition, sets the programmable counter 17 and the counter 26 of the number of pulses to the initial (zero) state. The registrar 27 is controlled by the signal from the output of the programmable counter 17. When a signal is received from the output of the programmable counter 17 to the control input of the recorder 27, the last measurement result is displayed. The minimum pulse duration at the output of the programmable counter 17, which determines the necessary speed of the recorder 27, is equal to the period T _{p the} repetition of the probe pulses.

Claims (1)

 DEVICE FOR MEASURING CHARACTERISTICS OF SEA WAVES, containing a pulse radar transceiver, the synchronization input of which is connected to the synchronizer output, a registrar and an envelope detector, the input of which is connected to the output of the transceiver, characterized in that, in order to improve the accuracy of measuring the height of surface waves, a line is introduced into it delays, pulse generator, electronic key, pulse counter, clock generator, four triggers, two electronic switches, three OR elements, AND element, etc. programmable counter, frequency divider, initial start-up block, analog-to-digital converter (ADC), two storage registers and two digital comparators, with the first trigger, element And, delay line, first electronic switch and pulse generator connected in series, the installation input of the first trigger connected to the output of the synchronizer, the output of the pulse generator to the control input of the envelope detector, the output of the transceiver to the second input of the element And, the output of which is connected to the second input of the first electronic about the switch and the reset input of the first trigger, the ADC input is connected to the envelope detector output, and the ADC output is connected to the inputs of the storage registers and the second inputs (B) of each comparator, the first inputs of which are connected to the outputs of the corresponding storage register, clock generator, electronic key, a programmable counter, the first OR element and the second trigger (installation input) are connected in series, the output of the second trigger is connected to the control inputs of electronic switches, the second input of the first OR element is connected to the output unit initial start-up, the output of the first electronic switch is connected to the ADC input, the output of the “End of conversion” ADC is to the input of the second electronic switch, the first output of which is connected to the control input of the second comparator, and the second output is connected to the control input of the second storage register directly and through the divider frequency - to the reset inputs of the second trigger and counters, the output A> B of the first digital comparator is connected to the installation input of the fourth trigger and the first input of the second OR element, the second input of which It is connected to the output A <B of the first digital comparator and the reset input of the fourth trigger, and the output to the control input of the first storage register, the fourth trigger (setup input), the pulse counter and the recorder are connected in series, the output A> B of the second digital comparator is connected to the control input of the first digital comparator and the reset input of the third trigger, and the outputs A = B and A <B through the third element OR - to the installation input of the third trigger, the output of which is connected to the control input of the electronic key, the output is programmable counter coupled to the control input of the recorder.

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