UA72621C2 - Method for accurately determining the location of an object, particularly a vehicle moving along a known course - Google Patents

Abstract

The invention concerns a method for determining the location and/or positioning of an object, in particular a vehicle such as a train moving along a known course, and this securely in terms of railway transport. The invention is characterised in that it consists in determining said location and/or positioning of said object by a valid calculation at a given time based on an elementary measurement involving at least a satellite and on a secure mapping of said known course.

Description

The present invention relates to a method of accurately determining the location and/or positioning of an object moving along a track that is determined using a special device.

It is understood that the term "track" means an area of space bounded by a tubular surface of arbitrary and variable cross-section, which strictly defines the boundaries within which the movement of the vehicle takes place. If the cross-section of this pipe can be neglected, then we get two equations that connect the longitude, latitude and height of the moving object.

More specifically, the present invention relates to a method of determining the location of a train moving along a railway track, the exact route of which is known.

The same principle can be applied when one equation is known (movement of an object on a : known surface).

The present invention relates to a method of determining the location and/or positioning of a vehicle, especially in relation to rail transport, i.e. the method allows almost instantly determining the location of the vehicle, or more precisely - the area of the absence of the aforementioned vehicle moving along a known route with a certain degree of probability .

Determining the location is based on the use of navigation satellites or similar terrestrial navigation beacons, hereinafter collectively referred to as "satellites".

The railway signaling system prohibits the train from entering a certain section of the track until it is established that the train in front has left the given section, that is, that the considered section of the track is free.

This must be established with a predetermined very small margin of error, and is particularly accurate in relation to rail transport; for example, sections on which the absence of a train is assumed must be determined with a maximum error value of the order of 109, preferably of the order of 1072, at each step of the calculation.

There is a known method of accurately determining the location of an object, and especially a train, by calculating the location based on signals from three satellites, and receivers that can receive information from the above-mentioned satellites are able to calculate the coordinates of the above-mentioned moving object with relatively high accuracy.

However, at the same time, accurate measurement of Greenwich time is required, which is quite difficult and expensive to perform at the level of a receiver, for example, placed on a train. Moreover, it is necessary that different satellites belong to the same group and use a single time reference system for them.

Thus, a fourth satellite is usually used, which allows you to accurately determine the location of the object in question by solving a system of four equations with four unknowns to obtain three coordinates of the point in question and the time value.

In fact, based on the knowledge of the coordinates of these satellites, the distance between the aforementioned satellites and the receiver of the object whose location is supposed to be determined is calculated.

Numerous technologies to improve the quality and/or increase the amount of information used, both in the civilian and military fields, have made it possible to increase the accuracy of these measurements.

In this regard, among others, the following may be mentioned: an increase in the number of satellites engaged in measurement (including those located on the ground); correlation between successive measurements in order to reduce the inherent weight of certain causes of errors; radio transmission (via satellite or other means) of information about local corrections (for example, about differential corrections of global positioning system signals transmitted by OSP5 speed, from UMae Agea A!ydtepiayop bZuziet - a guidance system for a large area of overlap - approx., translator); increasing the accuracy of measurements of time intervals by means of synchronization with satellites; use of operational and control information transmitted by ground tracking networks or networks of groups of satellites.

Various types of information are accumulated in order to specify the most likely location of the object of interest to us as much as possible and to increase the accuracy of determining its location.

Moreover, for reliable protection against electromagnetic interference or malicious actions possible during measurements, coding and the autocorrelation method are additionally offered.

Recently, in some cases, satellite positioning systems can be supplied with additional sensors that further increase the amount and quality of available information, for example, atmospheric pressure sensors in aeronautics, train axis sensors combined with Doppler radars, partially or completely inertial stations, etc.

Thus, the purpose of this invention is to propose a method and a device that provide accurate location and/or positioning of an object, especially a vehicle, such as a train, moving along a known route.

It is understood that the term accurate location determination means the location determination, or more precisely, the absence of a train on the section, which is re-determined at each calculation, with an error of less than 107, which preferably reaches 10712,

The present invention relates to a method of determining the location and/or positioning of an object, in particular a vehicle, such as a train, moving along a known route, especially in relation to rail transport, which is characterized by the fact that said location determination and/or said positioning of an object the project is carried out with the help of accurate calculations made at a specific moment in time, based, on the one hand, on primary measurements using at least one satellite, and, on the other hand, on the accurate cartography of the mentioned known route.

Preferably, said precise mapping allows obtaining two dependencies with three unknowns representing the coordinates of said object whose location and/or positioning is to be established, while at least one other dependency between the same three unknowns is determined by information, transmitted by at least one satellite whose location is known.

More specifically, the present invention relates to a method in which each primary measurement consists in determining an individual section of the aforementioned route between two path estimates, and the determination of said section depends on the standard deviation of the measurement error of the time of said primary measurement, the speed of light, a coefficient that depends on the coordinates of said the considered satellite and route, as well as from the coefficient, which determines the geometry of the error distribution of any measurement record in such a way that the probability of the absence of a train on the mentioned individual section is equal to the predetermined one.

Preferably, each recording of the measurement is duplicated, which allows to determine a large number of individual areas with the help of a large number of recordings of primary measurements, performed simultaneously, at the same given time, and based on the use of signals from different satellites or pairs of satellites.

According to the first embodiment, the primary measurement will be made using a pair of satellites having the same time reference system. Preferably, a pair of satellites belongs to the same group.

According to another preferred embodiment, the primary measurement is performed with the help of at least one satellite belonging to a group and a receiver connected to an object moving along a known route, and said receiver is synchronized with the timekeeping system of said group. to which the satellite belongs.

This suggests that to obtain a large number of primary measurements at the same time, it is enough to increase the number of satellites.

The general plot is usually defined as the intersection of various, mostly all, individual plots.

It is especially desirable to exclude individual sections that do not have common points with the general section.

Therefore, if there is a non-zero common area, the area of possible presence of the moving object is defined as the union of non-excluded individual areas.

From this it is concluded that the probability of the absence of the object on the combined site is defined as the product of the probabilities of the absence of the object on the known individual sites.

According to a preferred embodiment, the individual plots that define the combined plot depend on a parameter that defines the geometry of the error distribution, which is greater than or equal to the parameter selected for the assignment of the individual plots that define the common plot.

The invention also relates to a device for determining the location and/or positioning of an object, preferably a vehicle similar to a train moving along a known route, especially in relation to rail transport, which includes at least: equipment associated with said object, and the mentioned equipment contains at least one central computer, at least one receiver/decoder of signals coming from one or more satellites, a radio communication interface and a database containing a map of the route of the aforementioned object; central equipment, which includes a central computer, one or more radio communication interfaces, a data bus system, a database containing a route map: a program that allows changes to be made to the above map, and at least one console, and elements object/central equipment and person/moving object interfaces.

Preferably, the receiver/decoder includes a clock that is synchronized with the time system of the group of satellites.

Preferably, the device described in the present invention also contains a large number of additional sensors.

Preferably, the central equipment is portable.

The method for determining the location and/or positioning of an object, and in particular a train moving along a known route, can be considered in two different modes of operation: linear mode, in which the train moves along a track that does not have branches near its location; a topological mode in which a train is either about to enter a branching zone, or it cannot be reliably asserted that it has left this zone.

Mainly, this invention relates to determining the location of a train moving in a linear mode.

Examples of implementation in the topological mode of movement, for example, when passing through branching zones, are described below and allow you to quickly switch from the topological mode to the linear mode, and therefore apply the method according to the present invention.

Of course, the term vehicle moving along a known route generalizes various concepts, for example, a ship traveling along a network of canals, a car moving along a highway, the exact route of which is known, etc.

It should be noted that in the field of railway signaling, the route of the object, and more specifically, the train, is precisely and reliably known. Therefore, it is advisable to simply check whether the train is approaching a dangerous point (a specific section of the track) and give a signal of its presence to the train following it, so that the latter can pass this dangerous section without any risk of collision with the previous one.

The data recovery period in the railway system should be, at most, one to several seconds.

Linear mode

In this mode, the train is localized within the area bounded by the two waymarks, in other words, within the confidence interval given by the two curvilinear coordinates, in which, for the set route, the exact path of its passage is known (or at least, if not the exact path, probable track determined with a high degree of probability), it is possible to determine the absence of a train with a necessary low level of error.

The cartography of the route gives two precisely known equations that connect three coordinates (height, latitude, longitude). The cartography is stored in reliable databases and installed on the train at the start of operation, along with the fact that to guarantee the integrity of the content, standard security measures adopted in railway transport use coding and duplication. Database recovery is carried out, if necessary, preferably according to the appropriate protocol.

The third equation will be obtained on the basis of the primary measurement, with the help of at least one satellite, and preferably two satellites. Such a measurement is: or a measurement of the signal transit time from a satellite to a receiver located on a moving object (train), which determines the distance between the satellite and the receiver, if the receiver's clock is synchronized with the time reference system of the satellite group to which this satellite belongs ; or the measurement of the difference between the signal transit times from each pair of satellites to their receiver located on a moving object (train), if the receiver's clock is not synchronized with the time reference system of the satellite group to which this pair of satellites belongs.

It is worth noting that in the case of recording a primary measurement made using Two satellites belonging mainly to the same group, or at least to groups that use the same time reference system, there is no need to synchronize the clocks of the receiver located on the train, with this time reference system.

On the contrary, in the case when the primary measurement is carried out with the help of one satellite, it is necessary that the clock of the receiver located on the object moving along a known route be synchronized with the time reference system in the group to which this satellite belongs.

This increases the implementation cost of the method according to the invention, but reduces the number of satellites required for each primary measurement.

During the primary measurement (i-1), therefore, an attempt will be made to determine, using a system of equations (three or four) with many unknowns (three or four), the location of the aforementioned moving vehicle, or more precisely, the path section O ;, bounded on the track by two points

Mitip and Mitah, which are calculated from some arbitrary, but separate for each line, the distance reference point, and which are separated by a distance: 2Chassioi, where

Cha - a dimensionless coefficient that determines the geometry of the error distribution; c - speed of light; ой is the known standard deviation of the time measurement error, and ой is a dimensionless coefficient associated with satellite coordinates and the route.

If sii means the known standard deviation of the time measurement error during a given first primary measurement made, for example, with the help of the first pair of satellites, then zhschasii can be considered as the limit of the measurement error with a probability Pa (for example, from 102 to 107) that defines tsa as a dimensionless coefficient, which allows us to assume that the distribution in primary measurements satisfies the law

Gauss. Usually tsa is in the range from 1 to 4, preferably from 2 to 3. At the same time, if tsa is too large, it lowers the criterion of measurement accuracy, that is, it increases the level of probability of error. | on the contrary, if tsa is too small, the risk of non-convergence of measurements and, therefore, refusal to take into account the above-mentioned primary measurement increases.

Cha and the number of primary measurements (and, therefore, the number of involved satellites) should be chosen in such a way as to obtain predetermined probabilistic indicators.

It is worth noting that radiation includes a random distribution of errors, connected, for example: with the speed of propagation of waves in the ionosphere and troposphere; with the relative error of the calibration of the internal clocks of the satellites; with errors between their actual location and their estimated location; with synchronization errors with received messages; etc.

The primary measurement is repeated K times (with K satellites or K different pairs of satellites).

These K primary measurements can be performed using different groups. In this way, sections of the path

О»2а...ЮОкг are determined in the same way as Оч2.

If all these sections of the O2g path contain a subset of path markers that is common to them, then the common path section Oo2 is defined as the intersection of the sections of the paths 02. In this case, the parameters of the subsystem of the satellites used are in their normal mode of operation, at least for the measurements required in this moment. This can be set as a necessary condition in the calculation algorithm.

Moreover, if the conditions for the existence of Oo- are satisfied, the probability of the presence of an unknown distortion in the subsystem of the used satellites can be neglected; such a distortion would lead to the fact that the measurement would be invalid, or to an underestimation of the probability of error in the calculation of the path section. Otherwise, additional measurements can be made using one or two additional satellites.

It should be noted that the above description is based on the use of two satellites. The same description can certainly be given for individual satellites acting in concert with a receiver, provided the receiver itself has a clock synchronized with the time reference system of the group to which the satellite(s) belong. However, synchronizing the clocks with the group's timing system, such as using a cesium frequency generator, is still relatively expensive and it is quite likely that such a solution will not be considered.

If, finally, the pairs of satellites used belong to different groups, or if appropriate controls ensure that there is no standard error in a given group, then the probability that the object is actually outside the combined area is 0.2 (defined as a combination of individual sections ρ: 2πsotol) will, at most, be equal to (Р)x, which allows to achieve the required level of probability of error in the range from 107 to 10712,

The coefficient ц is defined as pso2la, provided that the probability P of the object being outside the section of the path 2псоиои is as small as possible (for example, from 103 to 105).

Within a given group, it is possible to achieve the absence of typical error, for example, by searching for the location of known fixed stations using the same pair of satellites. Corrections can be reported to the train either through the command post or using local radio communication. The time required for this operation must then be added to the estimated time.

Topological mode

As already mentioned above, the movement of the train in the topological mode should be transferred as soon as possible to the movement in the linear mode, so that it is possible to ensure the implementation of the method described in the present invention.

Consider an example in which one train follows another, and the track between them does not have any branching zones, the positioning of the train behind is carried out exclusively in linear mode; this allows you to calculate the limit of its advance based on information about the possible location of the tail of the train ahead, which may require direct or indirect communication with this train.

Similarly, when a train approaches a branch point, the system gives it a guarantee that there is no other object between the given branch point and the train itself, and gives it, for example, a (single-line) access right to pass through the branch points.

With this access right, it is possible to change the direction according to the route offered to this train by the control center. Having made sure that the branch point is set in the required position, and since the topology of the path of this train near the branch point is known, it is therefore possible to return to the previous option, that is, the method of determining the location in linear mode, although perhaps after passing the branch point , it will be necessary to change the reference point of the range in order to fix it for the new direction taken.

The right of access is returned to the branch point after the fact that the train has completely passed it is registered; then the given branch point is available to the following train.

Restoring access often results in map changes (new known direction).

In conclusion, the motion of the train described in this example has gone into linear mode.

Figure 1 shows a block diagram of the equipment that must be installed on the train to implement the method according to the first embodiment.

Figure 2 shows a block diagram of the equipment that must be installed along the route to implement the method according to the first embodiment.

Figure C shows a block diagram of the equipment that must be installed at the central post to implement the method according to the first embodiment.

Among the various embodiments of the method according to the present invention, the method described below is the most typical. It is described with reference to the above-mentioned drawings, which respectively describe the elements installed on the train, along the route and at the checkpoint.

Figure 1 shows the equipment that must be installed on the train to implement the method according to the first embodiment, in a variant that does not involve duplication in order to improve performance.

Depending on the technology used in the satellite receiver and decoder, this equipment may be duplicated so that information transmitted from different satellites is not obviously equally distorted in the event of failures.

Element 1 - the communication interface with the train (TI - Tgaiip Ipietase Opidyu is installed if the train protection function (ATP) is included in the system.

Element 2 - human-machine interface (MMI - Map Maspipe Ipiepase), is usually installed for dialogue with the driver. In cases of strict protection, which does not involve an alarm inside the cabin, this element is absent. Two cabins of this train can use the same computer 10.

Cartography From the route is a memory area with which the computer 10 works in normal mode, moreover, a procedure for controlling its contents via radio communication 4 and through the central post at the beginning of operation is provided. If necessary, the data recovery procedure is carried out on site. This may require driver confirmation via Element 2, Human Machine Interface (HMI).

Radio 4 is a standard interface that provides ground-to-train radio communication, analog or digital (for example, OZM-B).

In the computer 10 (in accordance with the safety principles adopted in railway transport) traditional coding technologies (for example, MIZAI or RIOAKE) or duplication (2 of 2) are used, which is used to improve the performance and is chosen at discretion (1 of 2, 2 of 3, 2 of 4).

The computer 10 is connected to the receiver/decoder of the signals of the first satellite 5 and to the receiver/decoder of the signals of the second satellite 6. Usually these receivers/decoders are multi-channel receivers/decoders and can simultaneously communicate with many satellites.

According to another embodiment, it is enough to install one receiver/decoder on the train, which has a clock synchronized with the time reference system of a group of satellites. In this described option, one satellite is enough to record each measurement.

To improve performance, various implementation options are possible, which, according to requirements, are supplied with additional elements: additional receivers; an additional radio communication interface; the architecture of the central computer with duplication (whose memory contains cartography data); partially or completely duplicated architecture of the human-machine interface (MMI) and the communication interface with the train (TI).

To implement options with increased accuracy, additional sensors 7 (acceleration sensors, gyroscopes, Doppler radars, etc.) can be provided if desired.

Figure 2 shows the basic option, which must be placed along the route and which can be duplicated to increase the reliability of the main facility control equipment.

If necessary, the controller 20 controls the corresponding component 22 on the route (object) and receives the necessary control data and state variables from it. It manages the right of access 23 and stores it when it is not in use by a train or portable or fixed specialist equipment. The radio communication interface 24 is similar to that used at the facility.

As in the case of the equipment installed on the object, various duplication options can be developed.

It is also possible to envisage portable road equipment intended for track walkers and for some urgent traffic control. In particular, it allows workers to accurately determine their location on the track, reliably restrict traffic (and later cancel restrictions) and, if necessary, receive warnings about approaching trains.

In one of the possible embodiments, the architecture of this equipment is very similar to the equipment installed on the object.

Human-machine interface (HMI) functions are changing: they do not include those based on dynamic information from the equipment (distance to the object, speed, etc.), but instead allow certain operations with system access rights.

The train communication interface (TI)) becomes the interface for notifying (e.g. via voice communication) of an approaching train.

In order to improve measurement accuracy near critical locations (eg station approaches) or to control the array of satellites in use, equipment additional to that tied to a fixed track location may be installed in appropriate locations. This equipment is very similar to that presented in Figure 1, but in this case it does not include either the train communication interface (TI) or human machine interface (HMI) elements. Moreover, it basically has no access control functions, but is intended only for the transmission of messages at the request of trains or a central post, while using instantaneous differences in location (linear position) for each pair of satellites involved in the system, the signals of which it can pick up . These discrepancies are used to narrow the confidence interval of the measurements and to verify the satellites used.

Figure C shows a central post according to the preferred embodiment, which is characterized by the fact that a minimum number of functions are performed in a protected mode. With the exception of cartography control, the main functions of the equipment are performed without referring to the protection system of the central post.

In practice, the equipment of the protection system 40, 41, 42, 43, 44 can be added to perform additional functions of the central computer 30: ensuring the safety of workers on the way, various protection devices, remote control functions for compatibility with non-completely equipped locomotives, backup information in case of work failure, etc.

Management of cartography 33 is not performed in "real time" mode, but in protected mode, using specialized equipment 38.

System structuring (priorities for trains, instructions for them, which allow establishing contact with various object controllers in order to obtain appropriate access rights, etc.) is carried out with the help of the central computer and the operator through the operational dispatch control console 42 and, according to with a preset schedule, through the schedule management console 41.

Control of operation and individual corrective actions (accidents, reservations for partially incomplete trains, etc.) can be performed through specialized consoles 40, 41, 42, 43, 44 (as shown in Figure 3) or, for example, through the above-mentioned console of the operational control room management. More specifically, the total number of consoles 40, 41, 42, 43, 44 is selected according to the guidelines.

Radio communication interfaces 34, 35, 36 provide communication between the central computer and satellites through the radio bus 37, which is usually duplicated. their 9 ry

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Claims (17)

1. A method of determining the location and/or positioning of an object, in particular a vehicle, such as a train, moving along a known route, especially in relation to rail transport, which is characterized by the fact that the said determination of the location and/or the said positioning of the said object the project is carried out with the help of precise calculations performed at a specific moment in time, based, on the one hand, on primary measurements, using at least one satellite, and, on the other hand, on the precise cartography of the mentioned known route, and the primary measurement(s) consists of determination of an individual section (0) between two points (Mitip and Mitakh), which is located on the mentioned route and depends on the standard deviation (vi) of the time measurement error of the mentioned primary measurement (i), the speed (c) of light, the coefficient (oc). which depends on the coordinates of the mentioned considered satellite and the route, as well as on the coefficient (pt), which determines the geometry of the error distribution of any measurement record in such a way that the probability (P) of the absence of a train on the mentioned individual section is equal to the predetermined one. 2. The method according to point 1, characterized in that two equations with three unknowns are obtained by means of accurate mapping, which are the coordinates of the said object whose location and/or positioning is to be established, while at least one more equations between the same three unknowns are obtained using information transmitted by at least one satellite whose location is known. 3. The method according to any of the previous items, which differs in that the record of the primary measurement is duplicated. 4. The method according to point 3, which is characterized by the fact that a large number of individual sections (0) are determined using a large number of records of primary measurements (i) performed simultaneously, at the same given time, and based on the use of signals from different satellites or a pair different satellites. 5. The method according to point 4, which is characterized by the fact that for the simultaneous recording of a large number of primary measurements, a larger number of satellites is used. 6. The method according to point 4 or 5, which differs in that the common section (Оо) is defined as the intersection of various, preferably all, individual sections (0). 7. The method according to point b, which differs in that individual sections (OO) that do not have common points with a common section (Co) are excluded. 8. The method according to point 6 or 7, which differs in that, if there is a non-zero common area (Co), the area (00), which is the union of non-excluded individual areas, is defined as the area of possible presence of the object. 9. The method according to point 8, which differs in that the probability of the absence of the object on the combined site (Oy) is determined as the product of the probabilities of the absence of the object on the known individual sites (0). 10. The method according to item 8 or 9, which is characterized by the fact that the individual sections (02) defining the combined section (Ou) depend on the parameter (po , which determines the geometry of the error distribution, which is greater than or equal to the parameter (po ), selected for the assignment of individual sections (Ог), which determine the general section (Со). 11. The method according to any of the previous items, which is characterized by the fact that the primary measurement is carried out using at least one pair of satellites that use the same time reference system. 12. The method according to item 11, which is characterized by the fact that the pair of satellites used in the primary measurement belongs to the same group. 13. The method according to any of items 1-9, which is characterized in that the primary measurement is performed using at least one satellite belonging to the group and a receiver installed on an object moving along a known route, and said receiver has clocks synchronized with the time reference system in the group to which the satellite belongs. 14. A device for determining the location and/or positioning of an object, preferably a vehicle similar to a train moving along a known route, especially in relation to rail transport, which includes at least: - equipment related to the mentioned object, and the said equipment contains at least one central computer, at least one receiver/decoder of signals coming from one or more satellites, a radio communication interface and a database containing a map of the movement route of the aforementioned object; - central equipment, which includes a central computer, one or more radio communication interfaces, a data bus system, a database containing a route map, a program that allows changes to be made to the aforementioned map, and at least one console, and elements of interfaces object/central equipment and person/moving object. 15. The device according to claim 14, characterized in that the receiver/decoder is provided with a clock synchronized with the timekeeping system of the group of satellites. 16. The device according to claim 14 or 15, which also contains a large number of additional sensors. 17. The device according to any of items 14-16, characterized in that the central equipment can be portable.