RU2506539C1 - Device to determine distance to water surface - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: invention relates to the field of radiolocation and may be used in systems to detect level of water reservoirs. The technical result is achieved due to introduction of two permanent memory devices, a unit of self-tracking by distance, an and-or element, a unit of detection of time mismatch between two signals, at the same time the group of outlets of the unit of minimum frequency detection, is connected via the first permanent memory device, via the unit of self-tracking by distance with the first group of summator inlets, having the group of outlets and the second group of inlets, accordingly connected with the group of indicator inlets and via the second permanent memory device with the group of outlets of the unit for detection of time mismatch between two signals, the inlet of which is connected with the outlet of the element and/or having the group of inlets, connected with the group of outlets of the unit of self-tracking by distance and the inlet connected with the outlet of this unit.

EFFECT: increased accuracy of detection of distance to water surface when there are waves.

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Description

The invention relates to the field of radar and can be used in systems for determining the levels of water bodies. A known device for determining the range to the water surface, presented as an "altimeter" and described in the book "Radio Engineering Systems", Yu.M. Kazarinov, 1990, M., Higher School, p. 355. It emits pulsed electromagnetic energy in the direction of the water surface and receives the signal reflected from it. However, the accuracy of determining the range is not always sufficient.

A device for determining the range to the water surface is described in the aforementioned source on pages 345-353, Fig. 16.1, which can perform the functions of an altimeter, where stationary transmitting and receiving antennas can be used, turned down and installed at a certain distance from the water level surface. With the help of a frequency modulator, the high frequency generated by the generator is changed into a stationary transmitting antenna turned down. The latter emits electromagnetic energy, which is reflected from the water surface and enters rigidly connected to the transmitting stationary receiving antenna. Electromagnetic energy is converted into electrical signals in the receiver, which includes an amplifier and a detector. The receiver also receives a changing frequency from the high-frequency generator. Since the frequency during the arrival of the reflected signal changes in proportion to the distance to the water surface, the frequency at the output of the receiver is equal to the difference between the frequencies from the generator and the reflected frequency. As a result, beats appear at the receiver output after detection, which are further amplified in the beating voltage amplifier. Since the distances to the horizontal portion of the water surface irradiated by the radiation pattern of the transmitting antenna will differ from each other, then to analyze the smallest distance equal to the distance along the central axis from the transmitting antenna to the water surface, an analysis of the beat frequencies is carried out using a parallel beat spectrum analyzer. The latter selects the expected beating spectra corresponding to the distances to the water surface and gives them to the block for determining the minimum beating spectrum. The selected minimum spectrum is then output from this block to the block for determining the minimum frequency, from the output of which a parallel code characterizing the range is sent to the indicator for display. However, in the presence of unrest, the accuracy of determining the range decreases.

Using the proposed device increases the accuracy of determining the range to the water surface in the presence of excitement. This is achieved by introducing two permanent memory devices, a range auto-tracking unit, an AND-OR element, a temporal mismatch determining unit between two signals, while the output group of the minimum frequency determination unit is connected via the first read-only memory device, through the range auto-tracking unit, to the first group the inputs of the adder having a group of outputs and a second group of inputs, respectively connected to a group of inputs of the indicator and through a second read-only memory GUT - a group determination unit outputs the time difference between the two signals, whose input is connected to the output of AND-OR having an input group connected to the group output unit automatic tracking in range and an input coupled to the output of this block.

In figure 1 and in the text the following notation:

1 - frequency modulator,

2 - high frequency generator,

3 - fixed transmitting antenna, turned down,

4 - parallel analyzer of the spectrum of the beats,

5 - beating voltage amplifier,

6 - receiver

7 - fixed receiving antenna,

8 is a block for determining the minimum beat spectrum,

9 - block determining the minimum frequency,

10 - read-only memory,

11 - an AND-OR element,

12 - range auto tracking unit,

13 is a block for determining the temporary mismatch between two signals,

14 - adder

15 - read-only memory device

16 - indicator

wherein the output of the frequency modulator 1 is connected to the input of the high-frequency generator 2 having the first and second outputs, respectively connected to the input of the stationary transmitting antenna, turned down 3, and to the first input of the receiver 6, having the second input and output, respectively connected to the output rigidly connected to the transmitting antenna of the stationary receiving antenna 7 and through the beating voltage amplifier 5 - with the output of a parallel beating spectrum analyzer 4, the group of outputs of which is connected to the group of inputs of the minimum detection unit the beating spectrum 8, having an output connected to the input of the minimum frequency determining unit 9, the group of outputs of which is connected via a read-only memory 10, through the range tracking unit 12 with the first group of inputs of the adder 14 having the group of outputs and the second group of inputs, respectively connected with a group of inputs of the indicator 16 and through a read-only memory 15 - with a group of outputs of a unit for determining the temporary mismatch between two signals 13, the input of which is connected to the output element and AND-OR 11, having a group of inputs connected to a group of outputs of the auto tracking unit over a range of 12 and an input connected to the output of this block.

The device operates as follows

Using the frequency modulator 1, the frequency is transmitted by the high-frequency generator 2 to the fixed transmitting antenna, turned down 3. The latter emits electromagnetic energy, which is reflected from the water surface and enters rigidly connected to the transmitting fixed receiving antenna 7. The antenna height can be for example, 40 m. Reflected electromagnetic energy is converted into an electrical signal in the receiver 6, which includes an amplifier and a detector. The receiver also receives a varying frequency from the generator 2. Since the frequency during the arrival of the reflected signal varies in proportion to the distance to the water surface, the frequency at the output of the receiver 6 is equal to the difference between the frequencies from the generator 2 and the reflected frequency. As a result, beats occur at the output of the receiver after detection, which are further amplified in the beating voltage amplifier 5.

Since the distances to the horizontal portion of the water surface irradiated by the radiation pattern of the transmitting antenna 3 will be different from each other, then to analyze the smallest distance equal to the distance along the central axis from the transmitting antenna to the water surface, an analysis is carried out using a parallel beating spectrum analyzer 4, tuned to the expected frequencies of these beats. An example of a specific implementation of the beat spectrum analyzer 4 is presented in the aforementioned book “Radio Engineering Systems” on page 353. Further, the beat frequencies come from the group of outputs of the analyzer 4 to the group of inputs of the block for determining the minimum spectrum of beats 8, which is a secondary processing unit that selects one node from a certain number of nodes, in particular, having a minimum beat frequency for a given time. An example of a specific implementation of the secondary processing unit is presented, for example, in the book "Radio Engineering Systems", V. Pestryakov. et al., 1985, p. 219. The beat frequency is determined in the block for determining the minimum frequency 9, the input of which is connected to the output of block 8, and this frequency is supplied in the form of a parallel code through a read-only memory 10, through a distance tracking unit 12 to the first group of inputs of the adder 14. In the read-only memory 10 each code characterizing the minimum beat frequency corresponds to a certain range. The auto tracking unit 12 allocates similar minimum ranges, including to the crests of the wave, following one after another. The range determination time depends on the repetition rate of a wave having a maximum height, the crest of which crosses the central axis of the transmitting antenna, turned down 3. The selected minimum ranges to the crest in the form of a code from the group of outputs of block 12 are sent to the input group of the AND-OR 11 element if there is permission from this block. If the crest is not highlighted by block 12, which can be observed in the absence of a wave, then such a resolution is not received, and the range information passes through the adder 14 without addition and is displayed on the indicator 16. The aforementioned secondary processing unit can also perform range tracking functions. From the output of the AND-OR 11 element, a signal indicating the presence of a minimum range is sent to the block for determining the temporary mismatch between the two signals 13. An example of a specific implementation of this block is presented in the book "Reference Book of Radar", Vasin VV, Stepanov BM , M., 1977, p. 214, Fig. 9.7.

The less often the signals from the AND-OR 11 element follow, the higher the wave of ridges. Therefore, to determine the range to the level of the water surface, which would have occurred if there had not been any disturbance, a value must be added to the aforementioned minimum range, the value of which depends on the time mismatch coming from the group of outputs of block 13 to the group of inputs of read-only memory 15 where for each value of this mismatch a certain value of the increment of range is sewn up, which must be added to the minimum range, which is done in the adder 14, where the second group of inputs receives a code from a permanent storage device 15. It should be noted that for different reservoirs the same increment of range will correspond to different time mismatches between the wave crests, intersected by the central axis of the antenna 3. Therefore, before starting work, you must install in a permanent storage device 15 range increment values.

As a result, the specified range from the group of outputs of the adder 14 is fed to the group of inputs of the indicator 16 for display. An embodiment without nodes 11, 13 is possible. For this, it is necessary to know the wave height in advance. At the same time, a range increment code corresponding to the height of the waves is output from the permanent storage device 15. But since the height can periodically change over time, the accuracy of determining the range will be lower.

The range determination time in the presence of waves can be several seconds, and in the absence of waves - a split second.

The proposed device can be used to determine the level of the surface of the water, for example, in locks, dams, pools and during ebbs and flows. The device can also be used to determine the thickness of ice in different parts of the water area. The accuracy of determining the range depends on the analyzer settings and can be 0.5-5 cm.

Claims (1)

A device for determining the range to the water surface, consisting of a private modulator, a high-frequency generator, a fixed transmitting antenna turned down, a parallel beat spectrum analyzer, a beat voltage amplifier, a receiver, a fixed receiving antenna, a unit for determining the minimum spectrum of beats, and a unit for determining the minimum frequency, where the output of the frequency modulator is connected to the input of the high-frequency generator having the first and second outputs, respectively connected to the input of the stationary transmitting a antennas turned down and with the first input of the receiver having a second input and output, respectively connected to the output of the stationary receiving antenna and through the beating voltage amplifier, to the input of a parallel beat spectrum analyzer, the group of outputs of which is connected to the group of inputs of the unit for determining the minimum beat spectrum, having an output connected to the input of the minimum frequency determination unit, characterized in that two permanent storage devices, a range auto tracking unit, an element and / or block are introduced determining a temporary mismatch between the two signals, while the group of outputs of the minimum frequency determination unit. 5 is connected through the first read-only memory device, through the range automatic tracking unit, to the first group of inputs of the adder having the group of outputs and the second group of inputs, respectively connected to the group of indicator inputs and through a second read-only memory device - with a group of outputs of a block for determining a temporary mismatch between two signals, the input of which is connected to the output element and / or having a group of inputs connected to the group of outputs of the auto tracking unit in range, and an input connected to the output of this block.