EP0881136A2 - Method to form the safe confidence range of a position fixing solution - Google Patents

Abstract

The method involves temporally and locally offset individual location measurements from which confidence intervals (VIP1,VIP2,VIPn) are updated. A predetermined minimum number of individual confidence intervals lead up to a reference point (tb). Maximal upper and lower limits of all intervals form the boundaries of a safety-relevant interval (SVIPb). The vehicle's actual position is obtained with regard to the reset limits by displacement-dependent update of the limit values.

Description

The invention relates to a method according to the preamble of claim 1.

From Signal + Draht 71 (1979) 11, pages 225 to 232 is a Procedure for self-locating a track-bound vehicle in the Route network of a railway system known with facilities is equipped for linear train control. For the Self-location there are two independent location facilities, namely one by wheel impulses of a vehicle wheel indexable path counter and a device for Detection of line crossing points. The outgoing and return lines of the line manager are at regular intervals of e.g. B, 100 m crossed and allow one with knowledge of the location an absolute location on the first intersection Track of the route. The actual driving location between neighboring crossing points is operated by the wheel Path pulse generator determined, its location indicated by Sliding and skidding is more or less faulty. The evaluation of the displacement encoder can therefore be done at Passed through a line crossing point postponed are so that the unavoidable measuring deviations of the displacement measuring devices each on a single line section are limited and in successive Sections not becoming one that may no longer be acceptable Add value. The only exception is the case that a line crossing point is not recognized; in this Trap the vehicle accepts that from the displacement encoder updated vehicle position until a subsequent synchronization through a line crossing point. Will neither do the two following line crossing points recognized, the location is lost and the vehicle is braked.

The present invention is based on such a method for self-locating a track-guided vehicle in which a first vehicle position that can be determined by any means is updated depending on the route until it is dependent on the route updated position finally through a then determined more current information is replaced. But it goes assume that one is determined by any means or recognized vehicle position by itself not necessarily also the actual position of a vehicle on the Distance must correspond. This is e.g. then not regularly the case when the location of a vehicle z. B. by Satellite location is determined. The satellite location results are system-specific with different cases Tolerances afflicted, so that at most determined can be that a vehicle is in a confidence interval between an upper and a lower limit, that can be reflected on the route traveled. in the the rest must also be assumed that for the Locating used electronics works incorrectly and so incorrect location results, d. H. not properly placed trust intervals of the vehicle position leads.

The object of the present invention is to follow the method the preamble of claim 1 to design and to further develop that despite the use of signal technology non-secure facilities for absolute location and relative distance measurement to location results with safety-relevant Confidence intervals leads.

The invention solves this problem by the characterizing Features of claim 1. The provided according to the invention Update of the confidence intervals, the multiple Typically unsynchronized single location results are assignable, it makes this possible based on consistency to check and from this a security-relevant trust interval to form the location; this security relevant Confidence interval may be earlier, so far At this point in time, a security-relevant trust interval was created - the provision of a derived when updating due to unavoidable measurement errors Relative distance measurement to broaden the confidence interval.

Advantageous refinements and developments of the invention Procedures are specified in the subclaims.

In the event that the single location results determined by a vehicle with those to be searched in the satellite positioning system Are subject to errors, claim 2 proposes to the Formation of the security-relevant trust intervals of one Localization solution to include trust intervals of the individual location solutions Validate retrospectively using correction data and verify, again referring to the path-dependent confidence interval of the relative path measurement to fall back on.

Although in principle it does not matter at what time trust interval to be classified as security-relevant is related, claim 3 suggests the time of last into the confidence interval to be formed Single location result. This solution has the advantage that the updated individual localization intervals at this time of the other single location solutions are already available and so immediately to the evaluation of the individual confidence intervals can be approached.

According to claim 4, those for updating the individual trust intervals trust intervals to be taken into account the relative path measurement are stored depending on the path or can be determined on the vehicles by estimation be; the predicted measurement errors can e.g. B. dependent be of the track inclination as well as the acceleration or deceleration of vehicles.

According to the teaching of claim 5, those involved in education of a security-relevant trust interval involved Single location solutions for consistency with the space curve traveled being checked. This ensures that single location solutions, that are not track-selective, on routes with Then branches are not included in the formation of the safety-relevant Confidence intervals are included when the There is a possibility that the location solution may be refers to a track other than the one under consideration.

According to claim 6, all single location solutions that are not in the path-dependent last confidence interval fit because they're either too big or up get a physically impossible travel path and thus are obviously unsuitable, sorted out and therefore not involved in the formation of the new confidence interval will.

It is necessary for the consistency check of the single location solutions a certain time. This time can be particularly important at Use of differential correction data with GNSS (Global Navigation satellite system) on the order of a few Seconds. Then according to the teaching of claim 7 the provision of the last updated route-dependent Confidence interval to a current new confidence interval only after completion of the validation and verification at a reference point in the past respectively.

If such a retroactive deferral of a path-dependent updated confidence interval on a then current security-relevant trust interval required then the vehicle is more or less advanced and the then deferred confidence interval limits are not for the current vehicle location more current. For this reason, the characteristics of the Claim 8 before, the confidence interval of the previously recognized Update the location up to the current validation time and then correct or adjust the new boundaries the security-relevant trust interval from the to the Confidence interval set by reference time path-dependent updating or by taking the Driving speed and driving time as well as the occurring Update measurement errors.

The individual location solutions should be advantageous according to claim 9 through transit time measurements to terrestrial or extraterrestrial Location transmitters are formed. Stand for it e.g. B. the Loran C and the GPS system are available.

According to claim 10, the location receivers should be as possible different technical characteristics used will. This creates the guarantee that any wrongdoing the location receiver to the location receiver concerned remain limited and have no effect on the location results of other location recipients; this expression increases the security relevance of the determined Confidence interval.

According to the teaching of claim 11, the individual Location solutions also advantageous by correlating current ones Route data obtained with corresponding reference data , for example by correlating radar signals via the route profile or the correlation of acceleration signals.

The single location solutions can be according to claim 12 by a certain number of preferably not synchronized Location recipients are formed, their confidence intervals are updated depending on the route. But it is the same possible according to the teaching of claim 13, only one To use the location receiver, which then at several times provides different single location solutions that are in turn updated depending on the path; the the latter solution, however, requires a highly reliable, monitorable location receiver because of any misconduct can affect all single location results.

Figur 1

ein Diagramm, aus dem sich das Zurückstellen eines wegabhängig fortgeschriebenen sicherheitsrelevanten Vertrauensintervalles auf ein dann aktuelles Vertrauensintervall ergibt und in

Figur 2

die Spiegelung der einzelnen Vertrauensintervalle auf eine Raumkurve.

The invention is explained below with reference to an embodiment shown in the drawing. The drawing shows in

Figure 1

a diagram from which the resetting of a path-dependently updated security-relevant trust interval to a then current trust interval results and in

Figure 2

the mirroring of the individual confidence intervals on a spatial curve.

For the illustrated embodiment, it is assumed that locating receivers arranged on a track-guided vehicle Single location results at different times t1 to tn have delivered, each of which has a confidence interval VIP1 to VIPn has, due to the respective location accuracy is defined. A confidence interval Route areas on both sides of a specific location solution, within which the actual driving location of a vehicle is based on a defined high probability; the Confidence interval can be symmetrical or asymmetrical extend to the location solution and be of different widths. The location solutions can be one or more Location recipients come who have their location results to different Deliver times, or from just one only location receiver that at different times different location results and their assigned confidence intervals provides. The confidence intervals in their chronological sequence are shown hatched in FIG. 1; the trust interval VIP1 applies to the point in time t1, the confidence interval VIP2 for the time t2 and that Trust interval VIPn for the time tn. None of these Single location solutions should be viewed as security-relevant, because every single location solution z. B. by a device defect can be totally wrong. Leaves through consistency checks but results from several individual location results with a security-relevant trust interval, by these single location results and their individual Confidence intervals checked for consistency will. Up to this point the vehicle can be used previously a security-relevant trust interval (also one of zero size) was determined recognize the route-related trust interval of the location, as shown in Figure 2 by the two thickly drawn upper and lower limits are defined as t0 * and su, t0 *; t0 denotes the past reset time, for the last time an absolute location result has been recognized as safety-relevant. This can e.g. B. that Passing a fixed influencing device be or the recognition of one determined by runtime measurements Location result with a corresponding security-relevant Confidence interval. The position of the Trust interval limits assigned to the vehicle at time t0 are based on worst-case assumptions by a Vehicle-side distance measurement has been updated, with increasing route the worst case scenario Measuring errors for a constant increase in the confidence interval the location leads.

It is not that the position of the location result at the time t0 using the approach since then Route is updated, which means the respective destination of a vehicle would be ascertainable, but rather the confidence interval limits this position solution are taking the maximum rejection of the vehicle measuring devices updated.

The confidence interval thus formed that at time t0 as absolute location solution recognized in terms of security now through the security-relevant trust interval of one be replaced by a new absolute location solution based on one later point in time, namely the reference time tb and with which the location errors that have accumulated so far are Vehicle distance measurement as far as possible in the result to be dismantled. A full compensation of the Influence of measuring errors on the confidence interval of the Localization would be possible if the current new confidence interval can be found without using the relative distance measurement could, e.g. if several location results at the same time would exist for the same location. But that is not the case because those for forming one are considered security relevant facilities to be recognized Assumed not synchronized in time to determine position but their individual location results are different Time t1 to tn at a distance of z. B. Provide for 1 sec. At the time tn there should be so many Single location results are available from a consistency check according to the m of the n principle, an absolute location result formed with security-relevant trust interval can be.

For this purpose, the limits of the confidence interval VIP1 of the individual location result determined at time t1 P1, t1 taking into account the maximum possible deviation the vehicle-side distance measurement up to Reference time tb updated, the confidence interval of this location result by those to be taken into account Measurement error of vehicle-side distance measurement increased; the broadening of the confidence interval is in figure 1 indicated by dashed lines. The measurement errors can be assumed to be constant along the way or as shown in the figure Embodiment assumed location-related vary. Updating the individual trust interval can z. B. bring about that in one Route atlas the parameters for forming the confidence interval the vehicle-side distance measurement depending on the location are. The measurement errors possible on one side or the other can be different for the individual locations; so arise z. B. by expected at individual locations Skidding or sliding as a result of starting or braking Displacement errors in one direction or another are particularly pronounced. These possible measuring errors can also z. B. by consideration of sudden accelerations or decelerations with the signals of the vehicle measuring devices calculated or estimated and then to form corresponding ones Confidence intervals of the vehicle-side distance measurement be used.

At the time t2, a locating device on the vehicle should have determined a second individual location result P2, t2, the the trust interval must be assigned to VIP2. This interval of trust too becomes path-dependent according to the confidence interval of the relative distance measurement, whereby the confidence interval increases. Within of the individual update areas come for the individual updated confidence intervals equal measurement deviations for use; the updated interval limits run parallel to each other.

There are so many absolute individual location results at time tn and so many confidence intervals for the individual location, that a security-relevant confidence interval SVIPb the absolute location can be formed. This trust interval is advantageous to refer to the time tn, where the last required single location result is available, can, however, in principle on any other Time tb related. At the reference point in time tb = tn the maximum and the minimum value for forming the safety-relevant Confidence interval used confidence intervals of the absolute single location results. These are the in the illustrated embodiment Values of the updated trust interval VIP2 of the at Time t2 determined location result; the top and Lower bounds of individual trust intervals can also be used belong to different confidence intervals. On the on the Time tb updated upper and lower confidence interval limits So far the location results will be applicable updated confidence interval of absolute SVIPo * location reset. From there it increases Confidence interval VIPb with the advancement of the vehicle increasing, a reduction again at a later date can then be made to a valid value. This reduction can in turn be checked by checking the consistency of several Single location results with individually assigned Confidence intervals happen or also punctiform at Passing a designated track device. In the latter The confidence interval assigned to this position then becomes the case to zero or a very small one Otherwise set to the value resulting from the value Updating the individual location results up to the new one Reference time results.

In the exemplary embodiment explained above, it is simplified been assumed that the consistency check of the e.g. B. three individual location results completed at time tb is, so that at this point also the provision of the safety-relevant updated depending on the route Confidence interval of an earlier location solution made can be. Usually, however, this consistency check is required a certain period of time, so that between the time ta the calculation of a current confidence interval and the time tb at which the provision is to be made, a certain amount of time passes. This period of time can well are on the order of a few seconds. The In this case, the confidence interval is corrected a past reference point in time tb. Of the The current location of the vehicle is then determined by updating the confidence interval reset to the reference time tb SVIPb according to the upper and lower Limit of the distance traveled since then Lu, ta or Lo, ta taking into account the possible discrepancies of the Distance measurement between the reference time and the current one Time ta at which the validation and verification of the Single position solutions is completed. The update the reset confidence interval limits can also from the advancing speed of the vehicle between the Reference time and the current time and the thereby Determine the defined travel time, taking into account any Measurement errors the confidence interval limits expand.

In the foregoing, it has been simplified to assume that the absolute individual location results at times t1, t2 to tn and their confidence intervals from these Times are updated. In fact, that individual location results at the aforementioned times be formed, but that through later available Correction values of the satellite positioning system verified will. Similar to the previously described reset the security-relevant confidence interval SVIPb the absolute Locating on the past The reference time tb also occurs with the individual location results after verification of the location result via the correction data provided for this one in the past directed resetting of the location results to the Times t1 to tn. The reset takes into account the confidence interval of the vehicle's distance measurement along the dashed line shown in Figure 1 Lines for the path-dependent consideration of possible measurement deviations the relative distance measurement. The reset location results and their confidence intervals are numerical the values involved in the formation of the security Confidence interval of those related to the reference time tb absolute location are involved.

FIG. 2 shows the times t1, t2 and tn verified single location results in the form of positions P1, P2 and Pn on the leveled space curve RK one Track applied and together with that for them applicable confidence interval. It can be seen that on projected the reference time tb as security-relevant confidence interval SVIPb is greater than that Trust interval VIPn of the individual trust interval at Time tn; the newly determined security-relevant trust interval SVIPb is definitely smaller than the path-dependent, security-relevant trust interval SVIPo * of the location at time t0.

The single location solutions, their individual trust intervals in the formation of a security-relevant confidence interval should be involved before the consistency check checked their confidence intervals to determine whether them with the space curve and its physically possible the history of the specified travel paths are consistent. Here it is checked whether the single location solutions are all on the same Space curve, making sure that between successive single location solutions no at least trivalent track node exists. Then namely can Single location solutions can be ambiguous and affect multiple ones Get space curves; their confidence intervals are therefore allowed in the determination of what is considered to be safety-relevant track-selective confidence intervals do not have to participate from the range of available, in the formation of a security-relevant trust interval of individual trust intervals to be sorted out, unless they are Tracking over this track node is clearly fixed and z. B. guaranteed by an interlocking.

The same applies to such individual trust intervals, which are larger than the laterally corresponding one as recognized security-relevant, by using the confidence interval the relative distance measurement updated confidence interval the last absolute location result. Such confidence intervals are obvious for outliers involved in the security-relevant determination of the confidence interval are not involved because they would prevent the updated security-relevant Reset the trust interval.

The facilities for self-tracking of guided vehicles in a route network can include the terms of terrestrial or extraterrestrial location transmitters to a location receiver determine from this the respective vehicle position to calculate; the use is advantageous of location receivers in different technical configurations, because this makes the danger not recognizable same disturbing influences based on location and measurement errors is reduced.

The vehicle-side location devices can the respective Vehicle position but also e.g. by correlating current sensor signals relating to the route with corresponding reference signals stored in a memory determine.

Claims (13)

Method for forming the security-relevant confidence interval of a position of a track-bound vehicle determined on the vehicle side on a space curve,
characterized,
that several individual location measurements are carried out at different times and / or locations, and that the confidence intervals (VIP1, VIP2, VIPn) assigned to the individual location results of the location are updated by using the confidence interval of a relative distance measurement up to a reference point in time (tb) at which a predefined one There is a minimum number (n) of individual confidence intervals and that the maximum or lower and lower limits of all individual confidence intervals updated to the reference point in time (tb) form the limits of the security-relevant confidence interval (SVIPb) to be formed and that - if available - the last recognized as security-relevant and also by application of the confidence interval of the relative distance measurement, the absolute confidence interval (SVIPo) of the location, which is updated, is deferred by the current security-relevant confidence interval. Method according to claim 1,
characterized,
that the confidence intervals of the individual location solutions involved in the formation of the security-relevant confidence interval (SVIPb) by retrospectively applying differential correction data for the satellite location system used to the individual location results found, in each case taking into account the confidence interval of the relative distance measurement for the route covered between the reference time and the validation time of the particular location solution , are formed. The method of claim 1 or 2,
characterized,
that the reference point in time (tb) is placed on the point in time (tn) of the most recently determined individual location result. Method according to one of claims 1 to 3,
characterized,
that for the path-dependent updating of individual confidence intervals, location-based or location-specific calculated and / or estimated parameters for the confidence interval formation of the distance measurement are taken into account. Method according to one of claims 1 to 4,
characterized,
that the individual location solutions (P1, t1; P2, t2, Pn, tn) involved in the formation of the security-relevant confidence interval (SVIPb) are checked beforehand for consistency with a space curve (RK) and its physically possible traversing paths specified by the history. Method according to one of claims 1 to 5,
characterized,
that the confidence interval of a single-location solution that does not fall within the current confidence interval that is recognized as security-relevant and is updated by using the confidence interval of the relative distance measurement, is not involved in the formation of the current security-relevant confidence interval (SVIPb). Method according to one of claims 1 to 6,
characterized,
that the trust interval (SVIPo *), which was last recognized as security-relevant, is only reset by the current trust interval (SVIPb) after the validation of the individual location results and their trust intervals has been completed at a reference point in the past (tb). Method according to claim 7,
characterized,
that for the determination of the confidence interval of the current position of a vehicle, the limits of the security-relevant confidence interval (SVIPb) at the time (tb) of its determination in accordance with the driving speed and the travel time between the reference time (tb) and the validation tent point (ta) or the distance traveled since then (Lu , ta; Lo, ta), in each case with the additional use of the confidence interval of the relative distance measurement, or that the reset of the confidence interval (SVIPo *) of the confidence interval previously recognized as safety-relevant and updated by using the confidence interval of the relative distance measurement only takes place at the time of validation. Method according to one of claims 1 to 8,
characterized,
that the individual location solutions are each formed by transit time measurements to terrestrial or extraterrestrial location transmitters. Method according to claim 9,
characterized,
that for the determination of the individual location solutions, location recipients are used in the most diversified possible technical form. Method according to one of claims 1 to 10,
characterized,
that the individual location solutions are each formed by correlating current route data with corresponding reference data previously stored in a route atlas. Method according to one of claims 1 to 11,
characterized,
that the individual location solutions are determined using several location receivers on one or more vehicles of a train set and are assigned to the route kilometrage via at least one location module, which establishes the relationship to the relative distance measurement and the location-based confidence interval of the relative distance measurement. Method according to one of claims 1 to 11,
characterized,
that the single location solutions are determined using at least one location receiver on a vehicle that creates several single location solutions at successive times, and that these single location solutions are assigned to the route kilometrage via a location module, which establishes the relationship to the relative distance measurement and the location-based confidence interval of the relative distance measurement.

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