RU2778364C1 - Method and device for determining locomotive movement parameters - Google Patents

Abstract

FIELD: measuring technology.

SUBSTANCE: invention relates to measuring technology, namely radar. The expected result is achieved by the fact that the device for determining the parameters of the locomotive movement contains transmitting and receiving antennas, a noise generator, tags, a switch, a high-frequency filter VHF, a low-noise logarithmic detector LLD, a low-frequency filter LFF, a matched load, ADC and microcontroller MC with the following connections: the noise generator is connected to the transmitting antenna, which is connected by probing signals to the tags, the latter, in turn, are connected by reflected signals to the first input of the switch, the output of which is connected to the MC through series-connected VHF, low-noise amplifier, LLD, LFF and ADC, its control output is connected to the second input of the switch, the output of the matched load is connected to the third input of the switch, and the information output of the MC is the output of the device with instantaneous speed signals and the value of the distance traveled, as markers for the geometry of the railway track, the cover plates of the rail and sleeper fasteners were applied and probing noise-like harmonic ultra-wideband radar signals called “radio light” were applied.

EFFECT: increase in the accuracy of measuring the parameters of locomotive movement in extreme operating conditions: large temperature differences, very low speeds and very high, severe climatic influences from deserts to polar latitudes, as well as vibration and shock loads.

2 cl, 5 dwg

Description

The invention relates to measuring technology, namely to radar, and can be used on railways (railways) to determine the parameters of the movement of the locomotive such as instantaneous speed, distance traveled, direction of movement.

A common problem in railway transport is the measurement of low speeds from the beginning of starting off and at the very end of the movement, up to a stop. This is due to the fact that mechanical sensors are used to measure the speed, which have a significant measurement error, in addition, they are not operable when slipping and skidding.

Short-range autodyne radars with frequency modulation are known, which are widely used in railway transport as measuring parameters for the movement of cars on marshalling yards, locomotives relative to the roadbed, occupancy detectors for turnouts and railway crossings, collision avoidance sensors, and much more. , see Noskov V.Ya. and “Modern hybrid-integrated autodyne generators of the microwave and millimeter range and their application”, part 9 “Radar application of autodynes. Successes of modern radio electronics”, 2016, No. 3, pp. 32-80.

Disadvantage: high complexity, insufficient accuracy due to high signal interference.

Also known is the patent of the Russian Federation No. 2378654 dated January 10, 2010 “Locomotive system for determining the speed and distance traveled”, which contains three receiving and emitting devices, each of which includes a microwave emitter unit with a transmitting antenna and a receiving unit of reflected microwave radiation with a receiving antenna. antenna and amplifier and a programmable microprocessor with two blocks of extremal correlation processing. All transceivers are located in series along the longitudinal symmetry of the rail and the reflected signals from the underlying ballast are perceived and analyzed using special software.

Disadvantage: a very complex circuit design due to the use of correlation processing, as well as unstable operation in extreme operating conditions.

This system is not applicable at all in high speed rail lines, which do not use sleepers, but only have a solid sub-base all the way, i.e. there is no ballast in the usual sense of the word, i.e. there are no benchmarks for reports.

At present, there is a tendency for the transition of electric railway transport at direct current to alternating current of industrial frequency, this gives a significant increase in performance simultaneously with the use of control of all motor (driving) wheels of the locomotive according to the motor / wheel scheme from the central processor. This imposes increased requirements for measuring motion parameters both at ultra-low (0.5–2 m/s) and high speeds (300–500 km/h).

The closest technical solution is the method of passive radar, the so-called radiothermal location (RTL), in which the coordinates of an object are measured by receiving electromagnetic waves emitted by the object.

Disadvantages: very complex algorithmic processing and, as a result, high hardware complexity, as well as large measurement errors. See the book "Fundamentals of radiothermal location" authors: V. I. Gadzikovsky et al., Yekaterinburg, USTU, 2001

The technical objective of the invention is to increase the accuracy of measuring the locomotive movement parameters under extreme operating conditions: large temperature differences, very low speeds and very high, severe climatic effects from deserts to polar latitudes, as well as vibration and shock loads.

The technical result is achieved through the use of overlays for fastening rails to sleepers as markers (marks) along the geometry of the railway track and optimal processing of signals reflected from markers using probing noise-like non-harmonic ultra-wideband radar signals, called radio lighting or radio light, which completely eliminate the effect of interference on the accuracy of measuring motion parameters, as well as the influence of vibration and impact loads.

In FIG. 1 shows a structural electrical diagram of a device according to this method, which shows:

1 - transmitting antenna A1

2 - receiving antenna A2

3 - markers (tags) overlays on the railway track for attaching rails to sleepers

4 - noise generator

5 - switch

6 - high-frequency filter (HPF)

7 - low noise amplifier (LNA)

8 - logarithmic detector (LGD)

9 - low frequency filter (LPF)

10 - ADC

11 - microcontroller (MK)

12 - agreed load (SN)

The circuit has the following connections.

The noise generator 4 is connected to the transmitting antenna A1, which is connected by probing signals to marks 3, the latter, in turn, by reflected signals, are connected to the first input of the switch 5, the output of which is connected through serially connected HPF 6, LNA 7, LGD 8, LPF 9 and ADC 10 with MK 11, its control output is connected to the second input of the switch 5, the output of the matched load 12 is connected to the third input of the switch, and the information output of the MK 11 is the output of the device with instantaneous speed signals and the distance traveled.

In FIG. 2 shows the curves of the influence of the storage device on the nature of the receiver operation:

- dotted curve without storage

- solid line with storage

In FIG. 3 shows the gain curves for the signal-to-noise ratio from the accumulator.

In FIG. 4 shows the position of the antennas and the path of the rays when the locomotive moves relative to two overlays when using one measurement channel.

In FIG. 5 shows the position of the antennas and the path of the rays when using two measurement channels, where A1 and A2 are the antennas of one channel, A3(A1) and A4(A2) indicate the initial position of the antennas of the second channel, and (A1) and (A2) the position of the antennas of the first channel in movement and passage over the overlay.

By radio lighting we will understand a local, artificially created noise (noise-like) field of broadband (ultra-wideband) radiation incoherent in space and time in the radio or microwave wavelength range. Radio lighting is implemented using one or more devices of incoherent radiation. Getting on nearby surfaces and objects, microwave radiation is partially absorbed in them, partially passes through them and is partially reflected. Thus, while spreading, it further carries information about the environment with which it interacts. In this respect, the situation is similar to the situation with ordinary (visible) light. The difference is that this is a different frequency range and different laws of interaction with the environment in which the process takes place. In addition, for ordinary light there is such a wonderful observation tool as the eye. To extract information about objects located in the zone of radio illumination (radio light), special sensors or systems of such sensors are needed.

The similarity between light and ordinary light is quite profound. In both cases, we are talking about incoherent radiation with a wide spectrum, which eliminates the effects of interference and reduces observation issues to assessing the power (and possible spectral, as in the case of color vision) characteristics of the received signal. The fundamental feature of radio light in relation to ordinary light is the enormous difference in the characteristic frequency range (by about five orders of magnitude) for light and radio light. The latter means a significantly lower potential resolution when using radio light compared to visible light.

A device with one measurement channel works as follows. In the underbody space of the locomotive, antennas A1 and A2 are located at a distance S equal to 45-50 cm from each other sequentially in the direction of travel. The radiation patterns (RP) of the antennas are directed at a certain angle down to the railway track on the side of one of the rails in such a way that the RP does not capture the rail itself.

When moving, the probing signals are reflected from the ballast and sleepers and overlays (marks), in the first case, the reflected signal is small in power, in contrast to the second case, see Fig. 2. When reflected from the overlays, time is recorded, and when passing the next overlay, time is again detected, this count is At and, knowing the distance S between the overlays, which = Const, we calculate the instantaneous speed using the formula:

where S is the distance between the pads

Δt is the transit time between two pads.

The distance traveled is determined by the expression:

The radio light receiver must "be able" to measure the total power of the passing UWB noise-like radiation. At the same time, it requires a sufficiently high sensitivity and a large dynamic range of the measured signal intensity. An essential parameter is also the degree of inertia of the receiver or the signal accumulation time. This parameter is closely related to the sensitivity of the receiver: the greater the accumulation, the lower the power of the incoming signal can be detected. On the other hand, the degree of inertia of the receiver is directly related to the possibility of its use in mobile conditions and limits the maximum possible speed of movement of the observed object.

Based on this, we formulate the requirements for the radio light receiver:

- the frequency band of the received signal must correspond to the frequency band of the emitted signal;

- signal accumulation time 0.001-0.1 s, which will allow the receiver to be used in situations with relative velocities of objects from 1000 to 10 m/s;

- dynamic range in terms of received signal power - not less than 40 dB, which will ensure operability when changing the range during signal accumulation. This parameter is closely related to the sensitivity in the free space between the receiver and the signal source by less than 100 times.

The devices closest in their properties that can be used as prototypes of radio light receivers are radiometric receivers and energy receivers used in direct chaotic communication systems.

Radiometric receivers, as a rule, have very good (in terms of requirements for radio light receivers) sensitivity characteristics, but they are characterized by a narrow dynamic range and significant inertia.

Energy receivers are used for digital data transmission. They register rapidly changing incoming signals (i.e., fast response) and have a large dynamic range, but are significantly inferior to radiometers in sensitivity.

The proposed radio light receiver combines the useful properties of radiometric and energy receivers.

To increase the dynamic range of the device, instead of the quadratic detector typical of radiometric receivers, a logarithmic detector with low-noise bandpass amplifiers at the input is used. The signal from the output of the low-pass filter of the detector is fed to the input of the analog-to-digital converter and processed by the microcontroller. The use of an ADC instead of a threshold device is the main hardware difference from ultra-wideband radio pulse receivers in direct chaotic communications.

шумов на входе фильтра

и полученные отсчеты суммируются в цикле от 1 до N. После этого цикл накопления завершается, выводится результат, обрабатывается полученное значения суммарного сигнала и цикл повторяется. Таким образом, выдача значения сигнала на отображающее устройство производится через каждые N×Δτ секунд. При этом уровень сигнала на выходе ячейки повышается по отношению к уровню сигнала на выходе ФНЧ фильтра (что соответствует однократному измерению отсчета) в N раз, теоретически чувствительность приемника увеличивается в

раз, а дальность приема в свободном пространстве увеличивается в

Однако растет и время наблюдения в N раз. Отсюда при выборе параметров функционирования устройства необходимо выбирать между повышением чувствительности приемной ячейки за счет накопления и возрастанием при этом ее инерционности. Использование микроконтроллера позволяет выбрать разумный компромисс при решении каждой конкретной задачи. Так, например, при визуальном наблюдении за силой сигнала время накопления может быть того же порядка, что и при смене последовательных кадров в телевизионном изображении (25-100 кадров в секунду), а для фиксации достаточно медленных изменений принимаемого излучения оно может достигать одной или нескольких секунд. По существу, от устройства измерения параметров движения (в частности скорости) потребуется только обнаружение меток, как видно из фиг. 2 левая часть - это отсутствие метки, а правая часть - наличие, можно сказать левая часть это лог. 0 а правая лог. 1, что очень удобно для вычислений в МК 11.The microcontroller accumulates the signal to increase the signal-to-noise ratio. For this purpose, the signal from the output of the low-pass filter is digitized at time intervals Δτ exceeding the correlation time

filter input noise

and the received readings are summed up in a cycle from 1 to N. After that, the accumulation cycle is completed, the result is displayed, the received value of the total signal is processed, and the cycle is repeated. Thus, the output of the signal value to the display device is performed every N×Δτ seconds. In this case, the signal level at the output of the cell increases in relation to the signal level at the output of the low-pass filter (which corresponds to a single measurement of the reading) by N times, theoretically the sensitivity of the receiver increases by a factor of

times, and the reception range in free space increases by

However, the observation time also increases N times. Hence, when choosing the operating parameters of the device, it is necessary to choose between increasing the sensitivity of the receiving cell due to accumulation and, at the same time, increasing its inertia. The use of a microcontroller allows you to choose a reasonable compromise when solving each specific problem. So, for example, when visually observing the signal strength, the accumulation time can be of the same order as when changing successive frames in a television image (25-100 frames per second), and to fix sufficiently slow changes in the received radiation, it can reach one or several seconds. As such, the device for measuring motion parameters (in particular speed) will only need to detect marks, as seen in FIG. 2, the left part is the absence of a label, and the right part is the presence, you can say the left part is a log. 0 and right log. 1, which is very convenient for calculations in MK 11.

In the second option, two identical channels are involved. In this case, the channels are arranged in series in the underbody space of the locomotive along the rail at a distance between the receiving antennas slightly less than the distance between the overlays.

The algorithm of work is the following. When the receiving antenna of the first channel passes over the overlay, the time countdown begins, when the receiving antenna of the second channel passes over the same overlay, the time count ends, for this, the microcontrollers of both channels are interconnected. Knowing this time interval Δt and knowing the distance between the receiving antennas, the instantaneous speed of the locomotive is calculated in one of the microcontrollers (let's call it the master) according to the known expression

где:

where:

L - distance between receiving antennas = Const

Δt is the time period for the receiving antennas of each channel to pass through the same overlay = VAR.

The distance traveled is determined by the following expression:

Note that the second option is somewhat more accurate, and this is important when measuring speed and distance traveled for high-speed trains.

We also note that this method does not have such a disadvantage as the harmful effect of interference inherent in coherent radar methods, since it is based on the reception of the energy component of the reflected signal (in contrast to the amplitude, phase, etc.). Another useful property of this method: it is not affected by vibration, shock and other types of interference, as well as the influence of harsh climatic conditions due to the same energy component.

Claims (10)

1. A method for determining the parameters of locomotive motion based on the use of radar incoherent ultra-wideband signals of dynamic chaos in the microwave range - "radio light", as well as on the use of artificial landmarks-markers along the geometry of the railway track in the form of overlays for attaching rails to sleepers, which consists in the fact that that as the locomotive moves, they emit probing signals of “radio light” onto the underlying railway bed, receive response reflected signals from ballast, sleepers and markers, and by the power of their characteristics along the entire route of the locomotive, marker points are found, and time is counted between adjacent marker points , noting the time when the signal is reflected from the marker and when the next marker passes, and knowing the distance between them, the instantaneous speed is calculated using the formula:

where ΔV - desired instantaneous speed; S - the distance between the overlays is constant; Δt - transit time between two adjacent patches of reflected signals, variable, the path is calculated by the formula:

where ΣΔν - sum of instantaneous velocities; ΣΔt is the sum of the instantaneous times for determining the parameters of the locomotive. 2. A device for determining the parameters of locomotive movement, including: transmitting and receiving antennas, noise generator, tags, switch, high-frequency filter - HPF, low-noise logarithmic detector - LGD, low-frequency filter - LPF, matched load, ADC and microcontroller - MK with the following connections: the noise generator is connected to the transmitting antenna, which is connected to the tags by probing signals, the latter, in turn, are connected by reflected signals to the first input of the switch, the output of which is connected to the MK through serially connected HPF, LNA, LGD, LPF and ADC, its control the output is connected to the second input of the switch, the output of the matched load is connected to the third input of the switch, and the information output of the MK is the output of the device with signals of instantaneous speed and the distance traveled, as markers for the geometry of the railway track, linings for fastening rails to sleepers are used and sounding noise-like harmonic ultra-wideband radar signals, called "radio light".

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