DE102009058912A1 - Method for geographic position determination of pedestrian, involves calculating prognosis coordinates for current habitation of navigation device, and calculating display position from measuring position and prognosis coordinates - Google Patents

Abstract

The method involves detecting a current measuring position for a current habitation of a navigation device by a position determining device. A quality value is assigned to the current measuring position, where the quality value is a value for measuring accuracy of the current measuring position. Prognosis coordinates for the current habitation of the navigation device are calculated based on number of positions and quality values. A display position is calculated from the measuring position and the prognosis coordinates based on the quality value. An independent claim is also included for a navigation device to perform a method for geographic position determination of a pedestrian.

Description

The invention relates to a method for determining geographical position, in particular a pedestrian, according to the preamble of patent claim 1. The invention further relates to an associated navigation device.

Generic methods and navigation devices for geographic position determination, in particular for position determination based on GPS-protected systems, are known from the prior art.

GPS position measurements are initially subject to inaccuracies. Sources for the inaccuracy of the GPS position determination are, among other things, the limited number or visibility of the satellites used for determining the position of the respective location of the GPS receiver, in the angular position of the visible satellite relative to the location of the GPS receiver (triangulation), in atmospheric Disturbances that can falsify the direction and thus the transit time of the satellite signals. Furthermore, the accuracy of position determination by means of GPS, especially in the area of high building due to reflections of the signals is significantly deteriorated. Likewise, errors in the necessary time determination lead to inaccuracies in the GPS measurement.

These sources of error typically lead to an accuracy (reproducibility) in the absolute position determination by means of GPS in the order of about 15 m in built-up areas. In addition, the GPS signal is often subject to a harmonic beating, which also involves a periodically fluctuating inaccuracy in the range of a few meters. However, this means that a single GPS measurement in itself is often not accurate enough to clearly determine the actual location of the receiver.

To solve this problem, various methods and means are presented in the prior art. On the one hand, this involves the use of further aids for a more precise analysis of the movement, which makes possible a more exact position for the determination. Among other things, the following aids are used in this so-called dead reckoning: Compass, acceleration sensors and pedestrian navigation pedometer. An example of this optimization of GPS navigation by means of dead reckoning is shown in the patent US 6,826,477 B2 , In particular, it is presented here that coupled position navigation through the connection of the GPS satellite signals with the measured values of an acceleration sensor makes it possible to obtain precise position determination. It is undisputed that, in particular with acceleration sensors in conjunction with the GPS position for the determination of an accurate navigation over a longer period of time is made possible.

However, such systems have the fundamental disadvantage that corresponding acceleration sensors or other measurement techniques must be present in the navigation device. This means, on the one hand, that an increased installation space as well as an increased weight must be carried along accordingly. Furthermore, such couplings of GPS satellite navigation systems and other sensors require additional computational effort, since an adjustment of the various sensors and measured values must be carried out at any time. In this respect, this causes an increased computational effort, thus limiting the capacity of the navigation device. However, if only a very small device with a low capacity is available and this is to ensure, for example, a mobile radio function, the coupling of different measurement signals can not be accomplished.

Alternative or additionally used navigation methods, inter alia for pedestrians, but usually for vehicles, use the so-called "map matching". In this case, a comparison of the measured positions from the GPS signals to a digital road map is performed. In built-up areas it is assumed that the pedestrian can only be on the respective street. Thus, measured values that lead to a position off the road are generally inadmissible. These positions are thus corrected and moved to the next allowable position on the nearest road. To determine the meaningful position on the road, there are a variety of methods and algorithms, in each case a digital road map is required. This inevitably results in the problem derived therefrom that such "map-matching" methods can only be used if the pedestrian or user is in a built-up area with a known road map.

From the above-mentioned embodiments of the prior art, the problem remains that it is not possible to perform the most accurate navigation possible, especially on open terrain, for which purpose a navigation device with limited capacity and without further aids can be used. The same also applies to wide roads, z. B. with several structurally separate lanes, as well as for large spaces or pedestrian areas. Again, it may happen in the prior art that you run from the place initially in the wrong direction until you leave after the place in a wegführenden Street gets notified that it is the wrong street.

Accordingly, it is an object of the present invention to provide a method and a device for determining the geographical position of a pedestrian, which allows the absence of a digital road map and without the use of additional measuring means based on the GPS signals as accurate as possible position determination.

This object is achieved by a method according to claim 1. The inventive solution of the task further comprises a navigation device according to claim 14.

Preferred embodiments of the invention are subject of the dependent claims.

The method for determining the geographical position, in particular of a pedestrian, first of all requires a navigation device. This comprises a position determination device, a processor, a memory and a display device. The position detection device usually consists of a GPS receiver, which performs a corresponding detection of the GPS signals, which in turn are emitted by the satellites. This position determining device delivers a measuring position in a cyclic interval, i. H. the GPS position, and at least one quality value for this measurement position. As a rule, the number of satellites available for determining the position provides a first quality value. The values (measuring position, quality values and possibly further data) are transferred by the position-determining device to the processor for further evaluation. By means of the method according to the invention on the basis of the current measuring position and its quality in conjunction with stored values, a display position is determined. Depending on the design of the navigation device and the user guidance, this display position can be displayed in a map section or a country / road map and / or in the form of geographical coordinates. For the presentation of the display position, there are many possibilities, which are well known in the prior art.

The task, the most accurate position determination possible without additional measuring equipment and road maps, is now solved by the inventive method. In the first step, the detection of the current measurement position for the current location of the navigation device by means of the position detection device - step (A). In this case, the measuring position is assigned at least one quality value, wherein the quality value is a value for the measuring accuracy of the respective measuring position. In the following step (B), the calculation of first prognosis coordinates for the current location is based on a plurality of preceding positions and quality values. In the final step (C), the display position is calculated from the previously calculated prognosis coordinate in conjunction with the measurement position as a function of the quality value of the current measurement position.

The current location of the navigation device corresponds to the true location, which is to be determined, which is therefore not exactly known. The measuring position or GPS position is determined by the position determination device in the known method. Their determination is therefore simple and well-known. For this purpose, there are a number of GPS receivers in the prior art which provide corresponding measurement positions. Due to the defectiveness of the measuring position, however, it is desirable to display a display position on the navigation device which corresponds as closely as possible to the actual location. The core of the invention here is to first determine prognostic coordinates on the basis of the past course in a method step, before a comparison of the measuring position and prediction coordinate to determine the display position takes place in a subsequent method step.

As already stated, the number of satellites which were available for determining the measuring position of the position-determining device advantageously forms a first quality value. This value is available in almost all known GPS receivers for each measurement position. Furthermore, a majority of the GPS receivers provide, as a further quality variable, the so-called horizontal position accuracy (HDOP), which likewise contains a statement as to how good the measurement quality of the respective measured value is. In addition, the GPS receiver can also provide additional quality values for each metric, depending on the type of execution. It is known that such GPS receivers sometimes fail to provide all available quality values for each measurement position. This may be the case, inter alia, if the cycle time was not sufficient to provide the corresponding quality values in the GPS receiver. If a data record is supplied by the position determination device to the processor without or only with partial quality values, the respectively missing quality value is replaced by a predefined value.

The data sets, ie the measurement position and the quality values, are generally transmitted by GPS receivers or the position determination device in a NMEA protocol. This from the National Marine Electronics Association (NMEA) defined communication profile between GPS receiver and processors ensures a uniform use of data of the position detection device in the processors, regardless of the particular type of GPS receiver used. Because of this restriction, which is advantageous for the method according to the invention, it is also not possible to carry out an alternative optimization method with the evaluation of the GPS raw data (regardless of the fact that this in turn would lead to an unacceptably high computing load).

The task in step (B) is to determine a prognosis coordinate for the current location. This is done in a preferred procedure with the following steps: First, a calculation of a measurement path between the last measurement position and the previous measurement position and parallel calculation of a Gewichtswegwegfaktors from the quality values of the current measurement position and the previous measurement position - step (B1). With the determined measuring path and the determined weighting path factor, a weighting measuring path is calculated from this - step (B2). From the combination of a plurality of past weighted measuring paths and the last weighted measuring path, the calculation of a prognosis distance is performed - step (B3). This forecast path symbolizes the expected distance traveled from the previous measurement point to the current measurement point. Finally, in step (B4), the calculation of the forecasting coordinate by means of the forecasting route is based on a previous position.

A graphic representation of the procedure will be explained with reference to the course sketched by way of example in the figures with associated description of the figures.

The calculation of the measuring path in step (B1) is preferably carried out as a vectorial difference between the current measuring position and the previous measuring position. This measurement path thus has a vectorial size with one length and one direction - step (B1a). In parallel, it is necessary to determine the weighting factor. For this purpose, a weighting factor is first determined for the current quality value or the quality values of the last measurement - step (B1b). This has a fixed range of values. In a simple implementation, the value range is set to the range between 0 and 1. This results in the fact that a weighting factor is assigned to each measuring position in a value range between 0 and 1. The required weighting path factor is now determined as the respectively lower weighting factor from the current measuring position and the previous measuring position - step (B1c). It is obvious that the order of calculation is arbitrary with the determination of the measuring path in step (B1a) for the determination of the weighting factors in steps (B1b) and (B1c).

In the following method step (B2), the calculation of the weighted measuring path from the respective measuring path takes place in a simple manner. For this purpose, the vectorial measurement path is simply multiplied by the weighting path factor. The weighting path factor preferably has a value between 0 and 1, and thus the weighted measuring path accordingly has a length between zero and at most the length of the measuring path, the direction being correspondingly identical to the measuring path.

In an advantageous embodiment, the weighting path factor and the weighting measuring path are determined with each new measured value and temporarily stored in the memory. Consequently, according to the maximum number of records, the most recent record is always deleted. The maximum number of stored data sets can depend on the quality values, but can also be fixed. Alternatively, however, it would also be possible to carry out the calculation of the weighted measuring paths for a plurality of past plug sections on the basis of the buffered measuring positions and quality values for each display position to be newly determined.

In step (B3), the prognosis distance is now calculated by adding up a plurality of weighted measurement paths vectorially starting from the last, current weighted measurement path. At the same time, the sum of the weighting path factors belonging to the weighted measuring paths is summed up. This summation takes place until the sum of the weighting path factors reaches a previously defined fixed value. Since in most cases the sum of the weighting path factors does not exactly yield the defined fixed value, in the exact execution of the calculation rule, the last weighted measuring path can be proportionally shortened, so that the proportionally associated weighting path factor in the sum leads to the defined fixed value, or it will alternatively, instead of the fixed value, the actual sum of the weighting travel factors is used for the subsequent calculation step. In this case, both the consideration of the weighting measuring path, whose weighting path factor in the calculation exceeds the fixed value, as well as its deletion can be used. The prognosis distance now results from the division of the vector sum of the weighted measurement paths by the fixed value. This forecast path symbolizes the expected movement from the time of the previous measurement to the time of the current measurement.

In an advantageous procedure, in a subsequent step (B4), the forecasting coordinate is determined from the forecasting route and the preceding display position. Since the procedural principle is to assume that the respective display position is closest to the true location of the navigation device, and since the prognosis route is the one assumed to correspond to the last movement, it is obvious to determine the prognosis coordinate to apply the forecast route to the previous display position.

After step (B), both the measurement position and the forecast coordinate are now known. Both positions indicate the possible location of the navigation device. It can therefore be assumed that the true whereabouts are probably between these two positions. Depending on the quality of the current measurement result in the GPS position determination, it is possible to determine which position is more likely to correspond to the true location. In this respect, a display position can be determined in step (C) by drawing a connecting line between the measuring position and the forecasting coordinate, the display position being on this connecting line. With a very good quality of the measurement result, d. H. a weighting factor in the upper value range, the display position is advantageously close to the measuring position and in contrast to a very poor quality of the measurement near the prognosis coordinate. A simple applicable calculation rule would be z. Eg "Display position = measuring position × weighting factor + forecasting coordinate × (1 - weighting factor)".

The aforesaid method can be used for pedestrian navigation as well as for any other means of transportation, although other more suitable methods are available in that case.

If, in pedestrian navigation, the calculation leads to an unrealistic speed for a pedestrian, in particular more than 20 km / h, it can be assumed that this is a serious measurement error. Of course, this does not apply if there is a constant overrun and thus can not be assumed by a pedestrian navigation. Since it is known that a pedestrian usually travels at up to approximately 12 km / h, in a preferred embodiment the method is supplemented by a correction of the last position in case of exceeding the speed limit. From the cycle time of the GPS receiver and the advantageous limit values for the speed, it is thus easy to apply a distance limit value for the path lengths considered in the navigation.

For this purpose, in one possible embodiment in pedestrian navigation, the length of the determined measuring path is additionally compared with the distance limit value in step (B1). If an excess of z. For example, given a converted speed of 20 km / h, two alternatives are available for correction: on the one hand, the quality value of the last measuring position can be reduced. Due to the advantageous method, this leads to a shortening of the last route section in the following calculation, since the quality value decisively influences the position displayed at the end of the method. In the second embodiment, it is also possible to move the last measurement position for further calculation on the previously determined last measurement path such that the measurement path is limited to an allowable length of z. B. 12 km / h shortened.

In an alternative or supplementary embodiment, it can be checked whether the initially determined prognosis distance in step (B3) would lead to an inadmissibly high speed, ie. H. again whether a defined distance limit has been exceeded. Corresponding to the assumption of a practicable speed for a pedestrian of about 12 km / h, a new maximum position is correspondingly determined, which corresponds to this relative speed of preferably 12 km / h. For the following calculation, the prognosis coordinate is determined by the maximum position in this case.

In an equivalent procedure, the consideration of a permissible maximum speed in the determination of the display position in step (C) can be performed. If a new display position has been determined, which exceeds the permissible limit value when calculating a resulting speed between the new display position and the previously calculated display position, a new maximum position is correspondingly determined, which corresponds to a relative speed of preferably 12 km / h. Now, a replacement procedure of the new display position by the determined maximum position. Thus, the display position given to the display device is the maximum position.

Although the value of 12 km / h is repeatedly named, this represents only an advantageous value. Likewise, a greater or lesser value can be chosen differently.

With regard to the direction of motion, a correction also makes sense. It is generally assumed that although one Pedestrians can suddenly change direction, but this does not occur repeatedly at short intervals in succession. On the other hand, under unfavorable circumstances, small changes in direction in conjunction with measured values shifted in the same direction in each case, ie due to measurement errors, can cause the user to display incorrect, oversubscribed changes in direction. By means of an advantageous correction of the change in direction, this problem can be eliminated by means of damping. It is deliberately accepted that when an actual change in direction, the true direction is delayed. A very good compromise has been found when the user is shown the correct direction after about 3 seconds. In common GPS receivers, a new signal is available once per second. Since a pedestrian can turn the direction by a maximum of 180 °, ie direction reversal, this leads to a fictitious permissible change of direction of 60 °.

In order to implement this advantageous addition to the method, in turn, various options are available, and in contrast to the correction of the speed, two fundamentally different procedures can be used:
In the Winkelkappungsverfahren, on the one hand, the change in direction to an allowable limit of z. B. 60 ° at 1 s cycle be limited. Ie. if a provisional change in direction is detected which is greater than the permissible limit value, a reduced direction change is used as a substitute for the following calculation, which is simply set equal to the limit value. This embodiment largely corresponds to the method for limiting the speed.

When the limit value is exceeded, consequently, a maximum position is determined, which results from the permissible change in direction.

On the other hand, in the angle division method, the direction change can be reduced to a fraction of the provisional change of direction. Ie. In this case, whenever the method step is used, the provisional direction change is always modified to a reduced direction change. According to the preceding explanations, the display should preferably correspond to the true direction after about 3 seconds, apart from measurement errors. With a cycle time of 1 second and the maximum possible change in direction of 180 °, this leads to an angle divider of 3 or a multiplication of the provisional change of direction with an angle factor of 1/3 to come to the reduced direction change. On the basis of the reduced change of direction, a new maximum position is subsequently determined. Depending on which direction change this supplemental method is applied to (i.e., on the measurement path, the forecast route, or the display path), it may be necessary or advantageous to include the previous directional change in the calculation of the reduced directional change.

In a first embodiment, the implementation of the advantageous check of the change in direction can again take place immediately after the calculation of the measuring path in step (B1). For this purpose, the provisional change of direction between the previous measuring path and the current measuring path is determined. As with the possible exceeding of a permissible speed, another option is available. It can exceed the limit of z. B. 60 ° with regard to the provisional change in direction of the quality value of the last measurement position can be reduced. Alternatively, the angular pitch or angle capping method described above may be used. In this case, a replacement measuring path is determined by means of the reduced change in direction, and a substitute measuring position is determined by means of the maximum position. In the following, the navigation method is continued with the replacement measurement position.

In the second type of application, it is advantageously possible to determine the preliminary change in direction between the forecast path and the previous display path after the prediction path determined in step (B3). In turn, the above-described angle division or Winkelkappungsverfahren can be used on this provisional change in direction. In the implementation, therefore, the reduced direction change results in a new replacement prognosis route, the prognosis coordinate being determined by the maximum position determined by the angle method. The calculation method is continued with this replacement forecast coordinate.

Alternatively or additionally, the test in step (C) on the provisional change in direction between the last currently calculated display path and the previous display path is also possible. Again, the angle division or angle capping method can be used. As a result, the reduced direction change thus generates the direction change to be displayed on the navigation device, and the detected maximum position becomes the display position notified to the user at the navigation device.

As is known, a pedestrian can change his locomotion at any time by z. B. a vehicle is used, the further pedestrian navigation according to the inventive method is unfavorable in the following. In this respect, upon detection of a multiple crossing of a distance limit between the current position and a previous position the navigation method for pedestrians are canceled. This limit is advantageously chosen at 20 km / h. The specified values in terms of speed with z. B. 12 km / h and 20 km / h are favorable assumptions. It is obvious that in a deviation thereof, the inventive method can be applied unchanged in an advantageous manner. Depending on the deviation, there are no noteworthy or recognizable deteriorations in the use of the pedestrian navigation according to the invention.

As a rule, the GPS receiver and navigation device operate in fixed cycles of mostly 1 second. Consequently, a conversion of speeds or angular velocities into lengths and angles is trivial. However, the method according to the invention is fully operational independently of a fixed cycle since it is only necessary to take account of the current time interval between the previous measurement and the current measurement at the appropriate place.

With regard to the further utilization of the display position for display on the display of the navigation device, there are other aspects to be considered, especially if from the last display path 13 a speed of less than 3 km / h results. Due to the inevitable error between the display position despite the procedure 03 and the true whereabouts result in short distances between the measurement positions consequently to percentage significant errors. On the one hand the indication of a current speed on the display does not make sense, since in particular this value is subject to a too large percentage error. Furthermore, it must be checked whether a new display position is displayed, or whether the previous position is left until a significant movement has taken place. Furthermore, it is conceivable to change the method according to the invention at a speed below preferably 3 km / h and to adapt it especially to the substantial standstill.

In a further advantageous embodiment, if the distance between the display and the measuring position is too great, then the measuring position is interpreted as the correct position and the history of the last measuring positions is discarded if the quality of the measuring position has improved significantly compared with the previous measuring positions. So z. B. in a satellite added directly done a much better position measurement, while according to the previous method, the actual adjustment to the correct position would be made only successively. By this method step, the better position is taken over immediately and the previous measurements with poorer quality no longer falsify the display position. The application of this additional process step is particularly useful in the startup phase of the navigation system. Since in this case the position can be determined more and more accurately at shorter intervals, significant positional jumps can occur, with each newer value in the initial phase usually being more accurate and therefore more accurate than the previous value. Regardless of the measuring position provided with an initially very low quality factor, this position falsifies the subsequently better measuring result.

The implementation of this supplementary method step can be carried out in a simple manner by checking whether the quality value of the new measuring position is many times higher than the quality value of the preceding measuring position or of the preceding measuring positions. Thus, for example, with an increase in the quality value beyond the factor 2 addition, z. For example, old value 0.3 and new value 0.7, the correction will be implemented. Equivalent calculations are possible. To maintain the usual calculation rule, the quality value of the preceding measurement position or the quality values of all previous measurement positions can be set to zero for this purpose.

According to the object, a device according to the invention is a navigation device, which uses a method for position determination according to one of the claims appended.

Advantageously, the use of the method according to the invention in a preferred navigation device, which is also a mobile device. This preferably has hereby small dimensions and low weight and consequently a volume of less than 200 cm ³ , in particular less than 100 cm ³ .

It should be expressly pointed out that for a better understanding of the method, in particular in the following explanations to the example shown in the figures, a consideration is made in a plane with two linear coordinates. In the implementation, however, the commercially available GPS receivers provide latitude and longitude geographic coordinates. However, these are known to be places on a sphere and consequently a - as simplified - calculation with "way = point-1 - point-2" is not possible. Rather, it requires an adapted calculation method based on the geographical coordinates. However, this is easily implementable for the skilled person due to mathematical relationships.

In the following figures, the inventive method is clear. Here, fictitious coordinates were chosen. Show it:

1 an exemplary possible course with a plurality of previous positions;

2 a section of the exemplary course of 1 ;

3 Maximum positions when limits are exceeded;

4 exemplary measured values of previous positions with measuring position and quality value;

5 the sequence of the calculation to determine the display position.

The 1 shows a possible course of positions over time, the positions being numbered consecutively with ".p0" to ".pn". The last measured and therefore current value with the measuring position 01.p0 and the associated forecasting coordinate 02.p0 as well as the current display position 03.p0 each have the number "p0". Iterative is used when determining a new measurement position 01 the numbering is pushed through and the previous "p0" becomes "p1". The measuring positions 01 are shown in the graph with circles. As can be seen from the graph of the illustrated graph, there is an initial direction of movement 20 , It follows a sudden change of direction 21 , which may be so justified, for example, that the pedestrian takes a different direction. The prognosis coordinates are in each case determined by means of the method according to the invention for the measurement positions 02 calculated. These are each shown as triangles in the graph.

As can be seen from the graph, the prognosis coordinate runs first 02 along the measuring positions 01 along the initial direction of movement 20 , When changing the direction of movement 21 This leads to the forecast coordinates 02 to an overshoot. Since, as is known, the prognosis coordinate is determined from the display position and the expected or predicted movement, it is obvious that in the prognosis coordinate there is the assumption that the previous traversed motion is retained, which however is not the case due to the change of direction.

In the further course, the measuring position is an example 01.p10 shown as a clear outlier as it can be caused by a very poor quality of measurement. A comparable poor quality shows the measuring position in the following course 01.p4 , Due to the poor quality of the measuring position 01.p10 this value is almost ignored and thus the forecast coordinates are running 02 largely independent of the faulty measuring position 01.p10 ,

With constant motion, the prediction coordinates are close to the measured points. Based on the mediation between measurement position and forecast coordinate, the display position becomes 03 certainly. This depends on the quality of the respective measuring position and thus runs close to the measuring position with high measuring quality or near the prognosis coordinate with poor measuring quality. As can be seen from the fictitious example, after about 10 measuring points, the direction changes 21 with subsequent uniform movement, the three positions with measuring position 01 , Forecast Coordinate 02 and display position 03 close to each other. Consequently, it can be considered that the display position to be displayed to the user comes very close to the true location.

In 2 the method according to the invention is clarified at a selected measuring point. In the past considered section is the measuring position 01.p5 with reasonably good quality. The next following measurement position 01.p4 has a relatively poor quality and below the measuring position 01.p3 a moderate quality. Based on the measurement positions provided by the GPS receiver 01 In each case the distances vectorially determined between the individual positions and thus give z. B. the measuring path 11.p4p5 as a distance between the measuring positions 01.p5 and 01.p4 , The same applies to the following and past routes. It is obvious that the inventive method is always applied in the presence of a new measuring position and in each case the calculation is carried out with respect to "p0".

Starting from the previously traversed measuring paths becomes the forecasting range 12 determined, ie at the measuring position 01.p3 the forecasting route 12.p3p4 , This forecasting route 12 symbolizes the expected movement between the previous position and the new position. Starting from the previous display position 03.p4 is created by creating the forecasting route 12.p3p4 the new forecasting coordinate 02.p3 certainly. Starting from the previous movement sequence, the navigation device would thus be the location of the forecast coordinate 02.p3 accept.

Between the measured position 01.p3 and the predicted coordinate 02.p3 can the display position 03.p3 be determined by a connecting line 15.p3 between measuring position 01.p3 and forecast coordinate 02.p3 is pulled. Depending on the quality of the measurement, the display position is 03.p3 closer to the measuring position 01.p3 or in this case with moderate quality closer to the forecast coordinate 02.p3 ,

This illustrated method repeats iteratively with each new measurement.

The further advantageous feature for use in pedestrian navigation is in 3 shown. 3a outlines the case that the new display position 03.p0 * a display path 13.p0p1 * which has a distance unrealistic for a pedestrian. In this case, the display position becomes 01.p0 * reset to a previously defined maximum position 17.p0 as the maximum permissible distance from the previous display position 03.p1 assuming a walking speed of 12 km / h. That means the new display position 01.p0 the maximum position 17.p0 is.

Equivalent is in 3b shown in terms of angle change 16.p0p1 * , It can be assumed that, as a rule, a pedestrian seldom suddenly changes direction. In order to dampen measurement errors, a maximum change in direction is therefore permitted in an advantageous embodiment. Likewise, the display position becomes 03.p0 * shifted to the permissible angle range and by a replacing maximum position 17.p0 certainly. The determined provisional change of direction of z. B. 90 ° can be exemplified by a reduced change in direction of z. B. 30 ° can be reduced according to the described Winkelkappungsverfahren. Equally, however, also in the angle division method, the determined provisional direction change can be multiplied by the angle factor according to the angle division method, and consequently this leads to the reduced direction change. In 4 is a table with sample measurements for the measurement position 01 each with a quality value 04 shown how they can be supplied by a position detection unit. It is obvious that each individual measured value may be accompanied by a plurality of further measured variables, such as further quality values.

The following 5 outline an advantageous procedure. In 5a is the respective measuring path 11 Listed from the measurement positions 01 is determined. Here is the measurement path 11 each formed from the difference of a measuring position minus the previous measuring position, z. B. measuring path 11.p2 = Measurement position 01.p2 - Measurement position 01.p3 , At the same time, a weighting factor is calculated for each position, this being determined by the quality values and a value range 06 is nominated with advantageous from 0 to 1. The following is for each individual measuring path 11 the valid weighting factor 07 determined, this in a simple way, the respective lower weighting factor 05 the associated start and end points of the measurement path 11 is. By multiplying the weighting factor 07 with the respective measuring path 11 becomes the weighted measuring path 14 certainly. It is obvious that this calculation method both with each new measuring point 01.p0 unique for each new measuring path 11.p0 can be performed, as well as retroactively in each case for all measuring points 01 ,

From 5b to 5c the step of calculating the forecast route takes place 12 , Here are the weighted paths 14 accumulated until the associated weighting path factors 07 in total a fixed value 08 to reach. This can be selected, for example, with "10". By dividing the sum of the weighted distances 14 by the sum of the weighting path factors 07 becomes the forecasting path 12 determined. By the vectorial addition of the forecasting path 12 to the previous display position 03 the forecast coordinate is calculated 02 , Based on the zu 2 explained method, the new display position 03 Determined from the comparison between the new forecast item 02 as well as the measuring position 01 ,

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• US 6826477 B2 [0005]

Claims (15)

Method for determining the geographical position, in particular of a pedestrian, by means of a navigation device having a position-determining device, a processor, a memory and a display device, wherein the position-determining device detects a measuring position in a cyclic interval ( 01.p0 ) and at least one quality value ( 04.p0 ), wherein by means of the processor a display position ( 03.p0 ), the display position ( 03.p0 ) can be displayed on the display device on a map and / or in the form of geographical coordinates, characterized by the following method steps with (A) detection of a current measuring position ( 01.p0 ) for the current location of the navigation device by means of the position-determining device, wherein the measuring position ( 01.p0 ) at least one quality value ( 04.p0 ), the quality value ( 04 ) a value for the measuring accuracy of the measuring position ( 01 ); (B) Calculation of Prognosis Coordinates ( 02.p0 ) for the current whereabouts based on a plurality of previous positions ( 01 . 02 . 03 ) and quality values ( 04 ); (C) calculation of display position ( 03.p0 ) from the measuring position ( 01.p0 ) and the forecast coordinate ( 02.p0 ) depending on the quality value ( 04.p0 ). Method according to claim 1, characterized in that in step (A) the number of satellites used to determine the measuring position ( 01.p0 ) were available to the position-determining device, a first quality value ( 04.p0 In particular, the horizontal position accuracy forms a second quality value, the respective quality value ( 04.p0 ) assumes a predefined value, provided that for the respective measuring position ( 01.p0 ) the number of satellites or the horizontal position accuracy is not provided by the position detection device. A method according to claim 1 or 2, characterized in that the position determination unit provides the measurement data in the form of a NMEA-equivalent protocol to the processor. Method according to one of claims 1 to 3, characterized in that the step (B) contains the following sub-steps: (B1) calculation of a measuring path ( 11.p0p1 ) from at least two measuring positions ( 01.p0 . 01.p1 ) and calculation of a weighting factor ( 07.p0p1 ) of at least two quality values ( 04.p0 . 04.p1 ); (B2) Calculation of a Weighted Measuring Path ( 14.p0p1 ) from the measuring path ( 11.p0p1 ) and the weighting factor ( 07.p0p1 ); (B3) Calculation of a forecasting route ( 12.p0p1 ) by means of a plurality of weighted measuring paths ( 14 ); (B4) Calculation of the Forecast Coordinate ( 02.p0 ) by means of the forecasting route ( 12.p0p1 ) and at least one previous position ( 01.p1 . 02.p2 . 03.p1 ). Method according to Claim 4, characterized in that the step (B1) contains the following substeps: (B1a) calculation of a measuring path ( 11.p0p1 ) between the current measuring position ( 01.p0 ) and the previous measuring position ( 01.p1 ); (B1b) Calculation of a Weighting Factor ( 05.p0 ) with a defined value range ( 06 ) from the at least one quality value ( 04.p0 ); (B1c) Determination of a Weighting Path Factor ( 07.p0p1 ) as the respectively lower weighting factor ( 05.p0 . 05.p1 ) of current measuring position ( 01.p0 ) and previous measuring position ( 01.p1 ). Method according to claim 4 or 5, characterized in that in step (B3) started from the last weighted measuring path ( 14.p0p1 ) a plurality of weighted measuring paths ( 14 ) is added up vectorially until at the same time the sum of the weighted measuring paths ( 14 ) associated weighting path factors ( 07 ) a fixed value ( 08 ), in which case the vector sum of the weighted measuring paths ( 14 ) by division by the fixed value ( 08 ) the forecasting route ( 12.p0p1 ) generated. Method according to one of claims 4 to 6, characterized in that in step (B4) the prognosis coordinate ( 02.p0 ) from the forecasting section ( 12.p0p1 ) and the previous display position ( 03.p1 ) is determined. Method according to one of claims 1 to 7, characterized in that in step (C) the display position ( 03.p0 ) on a connecting line ( 15 ), wherein the connecting line is the measuring position ( 01.p0 ) and the forecast coordinates ( 02.p0 ), whereby at the highest possible quality value ( 04.p0 ) the display position ( 03.p0 ) at the measuring position ( 01.p0 ) and where, with a steadily decreasing quality value ( 04.p0 ) the distance of the display position ( 03.p0 ) to the measuring position ( 01.p0 ) steadily larger and from the display position ( 03.p0 ) to the forecast coordinates ( 02.p0 ) is steadily decreasing. Method according to one of claims 4 to 8, characterized in step (B), when a distance limit value is exceeded with respect to the length of the previously calculated forecast distance ( 12.p0p1 * ), a maximum position ( 14.p0 ) and the forecasting coordinate ( 02.p0 ) replaced by the maximum position ( 14.p0 ) is determined, and / or that in step (C) when a distance limit value is exceeded with respect to the length of the currently calculated display path ( 13.p0p1 * ), a maximum position ( 14.p0 ) and the previously calculated display position ( 03.p0 * ) through the maximum position ( 14.p0 ) and the new display position ( 03.p0 ), wherein in particular the distance limit value is determined from a resulting speed of preferably 20 km / h and the maximum position is determined from the speed of preferably 12 km / h. Method according to one of claims 4 to 9, characterized in that in each case a provisional change of direction ( 16.p0p1 * ) between the previous display path ( 13.p1p2 ) and a) in step (B) of the forecasting path ( 12.p0p1 * ) and / or b) in step (C) the display path ( 13.p0p1 * ), whereby a reduced change of direction ( 16.p0p1 ) based on the provisional change of direction ( 16.p0p1 * ) and a fixed angle divider, wherein a maximum position ( 17.p0 ) in the reduced direction change ( 16.p0p1 ), wherein a) in step (B) the prognostic coordinate to be used for the following method steps ( 02.p0 ) and / or b) in step (C) the display position ( 03.p0 ) through the maximum position ( 17.p0 ), the angle divider having a value between 2 s and 4 s, in particular the value 3 s, divided by the cycle time. A method according to claim 10, characterized in that the determination of a reduced change in direction takes place only in the case that the provisional change in direction exceeds a minimum value, in particular the value of 30 ° / s. Method according to one of claims 1 to 11, characterized in that in step (B) or (C) in the case of multiple exceeding of a distance limit value between a current position ( 01.p0 . 02.p0 . 03.p0 ) and the previous position ( 01.p1 . 02.p1 . 03.p1 ), especially if the resulting speed exceeds the value of preferably 20 km / h, the navigation method for pedestrians is canceled. Method according to one of claims 1 to 12, characterized in that when in step (A) at an increase factor of the quality value ( 04.p0 ) of the current position ( 01.p0 ) divided by a previous quality value ( 04.pn ), in particular the previous quality value ( 04.p1 ), a set limit is exceeded, a devaluation of at least one previous quality value ( 04.p1 . 04.pn ) or the deletion of at least one previous measuring position ( 01.p1 . 01.pn ) is carried out. Navigation device, which uses a positioning method according to one of the preceding claims. Navigation device according to claim 14, characterized in that this also includes a mobile device, which is portable and has a volume of less than 200 cm ³ , in particular less than 100 cm ³ , has.

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