RU2679491C1 - Method of way navigation and review of front hemisphere of locomotive on railway geometry - Google Patents

Abstract

FIELD: radio engineering.SUBSTANCE: invention relates to radio engineering, in particular to radiolocation, and can be used on railways (railway) to determine the motion parameters of a locomotive, such as the instantaneous speed, the distance traveled from the beginning of the movement, the number of cross-ties passed and the coordinates of the locomotive at a given time, and control of the traffic situation in front of the locomotive at a distance of up to one or two kilometers, especially when it is possible that emergency situations arise. Technical result is achieved through the use of: short-range radar; four measurement channels (two consecutive for each monorail); high-range-resolution broadband probing signals; optimal processing of reflected signals.EFFECT: technical result achieved – improving the accuracy and reliability of measurement of motion parameters.4 cl, 5 dwg

Description

The invention relates to radio engineering, namely to radar and can be used on railways (railway) to determine locomotive motion parameters such as instantaneous speed, distance traveled from the start of movement, the number of railway sleepers traveled and the location of the locomotive at a given time, and control of the traffic situation in front of the locomotive at a distance of one to two kilometers, especially if contingencies arise.

A common problem along the train line is the timely detection of obstacles and interference that may lead to the premise of an emergency. Especially often, such obstacles are various transport equipment, which tends to die out at the crossing, most often at unregulated. A concrete fresh example. Regulated railway crossing near Vladimir, date and time: October 6, 2017, at about 3 a.m. Moscow time. Passenger high-speed electric train Moscow - N. Novgorod collided with a bus at this crossing. Reason: the bus violated the MPC, drove onto the railway crossing to the prohibiting red traffic light and died out, could not start again. The train driver in the light of the searchlight saw an obstacle only 300-400 meters away, braked urgently, but there was not enough stopping distance, an accident; 17 people died, many wounded.

The last carriage in front of the last train, people on the way, wild and domestic animals, rockfalls on mountain railways, fallen trees, etc. can also be an obstacle.

Almost the only way to detect obstacles on the railway track is the optical, that is, the look of the driver. Here the human factor comes into effect: fatigue, distraction, distraction, especially vision, also the correct determination of the distance to the obstacle that has arisen. In addition to this, sharp turns of the railway track, reducing direct visibility from the cab of the locomotive to this obstacle, as well as limited visibility: night, haze, fog, snow, heavy rain.

Thus, there is a need to minimize these factors that impede the timely detection of obstacles that have arisen and instruct any system to objectively and independently monitor the situation on the railway track with an alarm to detect obstacles, up to a decision on emergency braking. (in some cases, especially at railway crossings).

Currently, from known sources, the authors do not know about the presence of such a system in railway transport.

There are known attempts to create such a system for automobiles, mainly in the near infrared. Also known is an attempt to create an obstacle detection system based on an algorithm for generating a criterial function with autofocus, see Budai B.T. article “Ensuring the safety of driving vehicles in a colorful environment”, see proceedings of the 26th International Crimean Conference, Volume 10, M, Minsk, Sevastopol, 2016, p. 2367.

These systems show the visual environment, and in conditions of poor visibility and the selected frequency range, this, of course, reduces the efficiency of detecting obstacles.

Known autodyne short-range radars with frequency modulation, which are widely used in railway transport as measuring instruments for the movement of cars on sorting hills, locomotives relative to the roadway, employment detectors of turnouts and railway crossings, collision avoidance sensors and much more see Noskov V.Ya. and others. “Modern hybrid-integrated autodyne microwave and millimeter-wave generators and their application”, part 9 “Radar application of autodyne“ Successes in modern radio electronics ”, 2016, No. 3, pp. 32-80.

Disadvantage: short range up to 100-200 m.

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-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 and an amplifier and programmable microprocessor with two blocks of correlation-extreme processing. All receiving and emitting devices are arranged sequentially along the longitudinal symmetry of the rail and the reflected signals from the underlying ballast are perceived and analyzed with special support.

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

This system is generally not applicable in high-speed railways in which sleepers are not used, but there is only a solid underlying foundation all the way, i.e. there is no ballast in the usual sense of the word, i.e. no benchmarks for reports.

The closest technical solution is a system for comparing the reference and real path profile of a locomotive ahead using a radar, scanning along the elevation and azimuth in the range of 15-20 ° (“horizon profile”), the obtained data are compared with the reference profiles stored in the radar memory for various horizon profile points, the so-called digital roadmap. See Carlson G "Horizon profile checkpoint for low-altitude aircraft" - IEEE Transactions on Aerospace and Electronic Systems, 1976, v. AES-12. No. 2.

Disadvantage:

- only radar mode, there is no visualization of the path ahead and its immediate vicinity of the radiation pattern;

- the use of mechanical scanning of the antenna creates a number of inconveniences in operation and increases the cost of the system;

- the use of a phased antenna array with electronic scanning leads to a significant complication of the radar, and, therefore, the satisfaction of overall mass characteristics.

An object of the invention is to increase the accuracy and reliability of measuring motion parameters and create a system that does not need to install any additional reference elements along the rail track, or to receive signals from satellite navigation systems to determine the coordinates of a locomotive on a railway track, and , they need, as they say in the fleet, the "forward looking", i.e. it is important to see the real situation ahead of the path of the locomotive (from several meters to 1.5-2.0 km) as if the view from the driver’s cab, only with high resolution in range, in spite of any bad weather conditions: snow, rain, fog, etc. .

The technical result is achieved through the use of:

- short-range radar;

- four measurement channels, two consecutive for each monorail;

- broadband probing signals with high resolution in range;

- optimal processing of reflected signals.

To solve this problem, we propose a way of navigating and viewing the front hemisphere of a locomotive along the geometry of the railway track, based on short-range radar and using a road map, characterized in that it contains two radar systems - radar: the first scans the underlying surface of the track under the bottom of the locomotive, determining by selected reference points the current coordinates of the locomotive along the route and instantaneous speed, the second scans the front hemisphere along the route of the locomotive, about By sharing radar landmarks directly on the rail track and on both sides of it, the obtained results of scanning the front hemisphere are tied to the current locomotive coordinates determined by the first system, they are continuously compared with the road map and their compliance is evaluated and, in case of disagreement, a danger signal is generated, and the second The radar simultaneously builds a visual 3D image of the front hemisphere within the real-time radar line of sight, independent of weather conditions Wii.

In FIG. 1 shows a general structural electrical diagram of the implementation of this method, which shows:

1 - diagram as a whole;

2 - the first navigation radar;

3 - second radar - overview of the front hemisphere;

4 and 6 - blocks of the transceiver antennas of the first radar;

5 and 7 - calculators of the first radar;

8 - microcontroller of the first radar;

9 is a block of antennas MIMO review of the front hemisphere of the locomotive of the second radar;

10 - the electronic core of the second radar (ALU);

11 is a digital roadmap;

13 - Central processing unit (CPU);

14-monorail;

15 - lining for fastening the sleepers to the monorail;

16 - sleepers;

17 - reflecting objects on the railway track and on either side of it in front of the locomotive.

The circuit of FIG. 1 has the following compounds.

The outputs of the blocks of transceiver antennas 4 and 6 are connected to the computers 5 and 7 of the first radar, and the output of the block of transceiver antennas 9 of the second radar is connected to its electronic core 10, the outputs of both computers 5 and 7 of the first radar are connected to the signal inputs of the microcontroller 8, the outputs of both radars are connected to the first and second inputs of the CPU 13, respectively, with the third input of which is connected a digital road map 11.

In FIG. 2 shows a structural electrical diagram of one calculator 5 (second 7 is completely identical), which shows:

18 - microwave - generator;

19 - transmitter;

20, 21 - matched receivers;

22 and 23 - ADC;

24 and 25 - digital normalizers;

26 is a digital subtraction scheme;

A1 - transmitting antenna;

A2 and A3 are receiving antennas.

The circuit has the following connections:

The output of the microwave generator 18 through the transmitter 19 is connected to the transmitting antenna A1 of the transceiver antenna unit 4, and the output of the microwave generator 18 is connected to the second input of the matched receivers 20 and 21; the outputs of which are sequentially through the ADCs 22 and 23 and through the digital normalizers 24 and 25, respectively, connected to the first and second inputs of the subtraction circuit 26, the output of which is connected to the signal input of MK 8; control buses MK 8 are connected to the control inputs of the ADC 22 and 23, the microwave generator 18.

The first radar operates as follows. According to the control signal from the output of MK 8, the microwave generator 18 begins to generate a sequence of microwave signals that, through the transmitter 19, excite electromagnetic waves in the antenna A1, which are partially reflected from the underlying surface (sleepers, ballast), and mainly from the pads 15 with bolts and nuts on them, fastening the monorail 14 to reinforced concrete sleepers 16. The signals reflected from the lining 15 are received by the antennas A2 and A3 and through the matched receivers 20 and 21, and through the ADCs 22 and 23 are normalized to circuits 24 and 26, where I have them LF components. Then, the extracted low-frequency signals are supplied to the subtraction circuit 26, while the moments of time when the signals from the subtraction circuit pass through a zero value are recorded. And the time interval ΔT between two samples of the passage of zero is calculated.

The time moments of passage through the lining by the antennas 4 and 6 (calculators 5 and 7) are recorded in MK 8, where the time interval ΔT is calculated, and the locomotive’s linear speed, the distance traveled and the number of sleepers passed and all the calculated parameters are transferred to the CPU 13 for further processing.

In FIG. 3 shows the voltage curves at the inputs and outputs of the subtraction circuit 26, which shows:

27 - voltage curves at the output of the second calculator 7 (input 2 of the subtraction circuit 26);

28 - voltage curves at the output of the first calculator 5 (input 1 of the subtraction circuit 26);

29 - voltage curve at the output of the subtraction circuit 26;

30 — transition points through zero of the difference signal of both calculators;

ΔT is the transit time of the middle of the sleepers lining between the second and first calculators (between adjacent points of transition through zero).

где S - фиксированное расстояние между антеннами 4 и 6, ΔT - время межу переходами через ноль антенн A3 и А2, именно в этой послеовательности.The linear speed of the locomotive is determined by the simplest formula S = V * t, and knowing the distance between antennas 4 and 6 (for example, 3 meters) and the time between the moments of fixation (crossing zero of each recorder), then the speed

where S is a fixed distance between antennas 4 and 6, ΔT is the time between the transitions through zero of antennas A3 and A2, precisely in this sequence.

For high-speed railways (300-500 km / h), you can take the time interval ΔT for a larger number of zero marks, for example, 5, then

Fixing each sleeper, we determine the location of the locomotive on the road map, and integrating the speed values, determine the distance traveled.

Thus, the operations according to the claimed method allows to measure the linear speed of the locomotive and the distance traveled with high functional reliability.

The device according to this method is installed under the bottom of the locomotive at a height of 0.5-1.0 m above the level of the rail head. The distance between antennas 4 and 6 - the base (optimal) can be taken equal to three meters. Knowing the number of railway sleepers traveled, the location of the locomotive and the significance of the driver’s action are determined using the roadmap: pick up speed (slow down) to a certain value, slow down to a stop, etc. When the locomotive (device) moves over the railway track, the intensity of the reflected signal is periodic, due to the periodicity of the sleepers in the rail-sleeper. The nature of the change in the reflected and received signal when moving the locomotive, and, consequently, the device (namely, the presence of a zero of the received signal when it is above the middle of the next lining) allows you to determine the number of railway sleepers traveled and thereby the position of the locomotive on the rail track, also by comparison with the road by card.

In FIG. 4 shows a simplified structural electrical diagram of a second radar 3 (obora of the front hemisphere), which shows:

31 - microcontroller MK;

32 - microwave key (switch);

33 - multifunctional receiver;

34 - amplifier-modulator;

35 - voltage controlled oscillator (VCO);

36 - power divider;

37 - amplifier-filter for the beat signal;

38 is an amplifier filter for the heartbeat signals.

The scheme of the second radar has the following connections:

38 is a visualization diagram (3D image - monitor).

The circuit has the following connections: MK 31 bi-directional bus connected to a multifunction receiver 33, the second output of which is connected to the control input of the microwave key 32, and the first output through the amplifier modulator 34, VCO 35 and the power divider is connected to the input of the power amplifier and through the mixer filter the beat signal 38 - with the information input of a multifunction digital receiver 33; the output of the power amplifier 37 is connected to the first input of the microwave key, the output of the receiving lines of the MIMO 9 frames is connected to the second input of which, the first output of the microwave key is connected to the transmitting lines of the MIMO 9 frames, and the second output is connected to the other input of the beat-signal mixer-filter 38; the first output of MK 31 is the output of the second radar and is connected to the second input of the CPU 13 (Fig. 1), and the second output is connected to the visualization unit 38 - monitor.

The basis for constructing the circuit is the following principles of the radar, designed to build three-dimensional radio-frequency images of the sensing object:

- probing signal with linear frequency modulation (LFM);

- correlation and filter processing of the reflected signal, internal coherence of the system;

- radio holographic image synthesis (synthesized aperture method);

- Fixed multi-channel antenna system MIMO.

The purpose of their application is to achieve:

- high resolution in range due to the use of ultra-wideband sounding signal;

- high angular resolution due to the synthesis of the aperture when using small antennas;

- fast scanning process.

The second radar operates as follows:

Under the control of the MK 31 microcontroller and simultaneously with the launch of the ADC, it generates a probing LFM signal in the frequency range from 2 GHz to 4 GHz.

The band-pass filter amplifier 37 filters out the useful spectral components of the beat signal corresponding to operating ranges from 5 m to 1-2 km, and also prevents the imposition of spectra in the subsequent analog-to-digital conversion.

The multifunctional digital receiver 33 is designed to digitize the beat signal from the output of the analog filter-amplifier of the beat signals 37, form data packets and transmit them to the processing unit (ALU). In addition, the digital receiver controls the operation of the microwave key 32 in synchronization with the operation of the ADC.

At the command of MK 31, the conversion to each modulating voltage report at the output of the DAC is started; an ADC report is generated. The ADC has 18 bits and a performance of up to 1 Megasample per second. The operation of the DAC and ADC is controlled by the MK 31 microcontroller, which synchronizes the operation of the ADC and DAC, reads the digitized data from the ADC output and transmits them via the standard RS232 (USB) interface to the processing unit. The circuit has two independent ADC channels, so quadrature signal processing is possible. The DAC is used to generate the corrected sawtooth voltage for the VCO transmitter 35. Memory is needed to store the signal samples during sounding.

The second radar is multifunctional. It can work both in the high-frequency version of the locator, generating simulating voltage through the DAC for the VCO, and in the low-frequency (for 3D image) up to 400 MHz due to the presence of DDS (direct digital synthesis).

The MK 31 microcontroller has two discrete I / O ports. They are used to control the switching of antennas (high-frequency version) or for

In FIG. 5 shows the general structural diagram of the antenna arrays of the second radar, consisting of 4 antenna frames, each of which is two transmitting lines and two more receiving lines, it shows:

a - line of transmitting antennas;

b - line receiving antennas;

c - effective aperture.

In reality, the number of cells is determined by the technical requirements for the system: range resolution, required radiation pattern, etc.

MIMO frames in the amount of four pieces of 4 receiving and 4 transmitting emitters in each are mounted on the corners of the locomotive's windshield, the direction of the maximum radiation of each individual emitter in the frame and all four frames as a whole turns out to be such that the partial radiation patterns are folded in the right direction. This system of 4 small-sized frames is used on the second radar (front hemisphere overview).

In the first radar (navigation), the transmitting and receiving antennas can be made on the basis of elementary radiators or in the form of helical antennas.

The operation of the front hemisphere viewing system is based on the principle of a broadband synthetic aperture radar; probing signal with linear frequency modulation; correlation-filter processing of the reflected signal with internal coherence. This allows you to get high resolution, high angular resolution due to the synthesis of the aperture when using small antennas as part of MIMO rulers or matrices (MIMO is Multiple Input - Multiple Output, multiple input - multiple output).

The system of two radars operates as follows. When the locomotive of the first radar moves, its location is continuously measured and the instantaneous speed value is calculated and this data is transmitted to the central processor. At the same time, the second radar system scans the front hemisphere of the railway track by locomotive movement and determines all radar reflective landmarks, transmitting their coordinates also to the CPU. These landmarks can be lineman's booths, transformer substations, mobile communications masts, railway crossings, etc. The CPU compares these obtained landmarks with the landmarks recorded in the digital roadmap. With the coincidence of these landmarks among themselves, it is believed that everything is in order. If there are differences, especially at railway crossings: a stuck vehicle, a laden cargo, etc., then this is an emergency situation and the CPU gives a signal to the driver and over the radio channel to the control center and emergency braking is performed by the driver's command or automatically.

The system can also detect and give signals about the presence of people (group), wild and domestic animals (herd) on the railway track, as well as vehicles that are only approaching the railway crossing and much more, including the oncoming train along the same track (emergency situation, it happens).

The joint work of these two radars can significantly increase control of the traffic situation on the path of the locomotive and increase traffic safety.

The system is especially effective in detecting emergencies, for example, when monitoring unregulated crossings, which are the majority of train collisions in motor vehicles, including tractor ones, this also includes various agricultural self-propelled vehicles, as well as special equipment in the form of excavators, loaders and others, since the drivers of the above vehicles are not very friendly with the rules of the road, and also do not always comply with the “dry law”, hence the emergencies.

The application of this method allows you to identify obstacles encountered at the railway crossing for 1.5-2.0 km., Which will certainly avoid a collision, since, knowing the distance to the crossing and the speed of the locomotive, the CPU will easily calculate the type of braking, up to emergency.

It should also be noted that determining the distance to the crossing does not depend on weather conditions, such as rain, snow, fog, etc.

Special marks are made on the road map about railway crossings, and the CPU, when the locomotive approaches them at a distance of 1.5-2.0 km, gives an audio and light signal to the driver so that he is especially attentive.

The CPU also compares the marked marker points of the railway track with the accepted second radar marks reflected from them by the road map and corrects (if necessary) the location of the locomotive on the railway track.

It should be noted that the front hemisphere turnaround without reference to the locomotive’s location at any given moment in time, which means that the obtained radar portrait corresponds to the forward-facing traffic situation, has a half solution, because there may be an admission of an obstacle or vice versa a false signal about its presence.

Consequently, the system should have two components: the radar of the directional navigation and the radar of the obor of the front hemisphere that are rigidly interconnected in time and in the position of the locomotive on the railway track.

The second radar can simultaneously operate in radar mode and, together with the first radar, forms a complete system, and additionally, in the visualization mode of the terrain, helping the driver in directional orientation, especially in bad weather.

Claims (4)

1. A way of navigating and viewing the front hemisphere of a locomotive according to the geometry of the railway track, based on short-range radar and using a road map, characterized in that it contains two radar systems - radar: the first scans the underlying surface of the track under the bottom of the locomotive, determining by selected reference points the current coordinates of the locomotive along the route and instantaneous speed, the second scans the front hemisphere along the route of the locomotive, determining the radar on the rail track and on either side of it, the obtained results of scanning the front hemisphere are tied to the current coordinates of the locomotive determined by the first system, they are continuously compared with the road map and their compliance is evaluated and, in case of disagreement, a hazard signal is generated, and the second radar is simultaneously building 3D visual image of the front hemisphere within the real-time radar line of sight. 2. The method according to p. 1, characterized in that the scanning range of the front hemisphere lies in the range from 100 m to 1.5-2.0 km. 3. The method according to p. 1 or p. 2, characterized in that the following landmarks are applied to the railway track and near it: level crossings, masts, walkers booths, special marker points, etc. 4. The method according to p. 1, characterized in that the first radar contains two channels for measuring the passage of the same lining on the sleepers.

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