DE102011012647A1 - Method for operating navigation system mounted in motor car, involves detecting allowed last road element according to parameter set during route computation analysis of the computed route on basis of parameter set - Google Patents

Abstract

The method involves determining start point of target point. The optimum route between the start and target points is computed based on map data in card memory device using parameter set. The failure of route computation is detected. The modification of parameter set is performed. The optimum route between start and target points is re-calculated using modified parameter set. The allowed last road element is detected according to parameter set during route computation analysis of the computed route on basis of parameter set.

Description

1. Brief description of the invention

• • Der User fährt einen Lkw, will aber in eine für Lkws gesperrte Zone.
• • Der User verbietet Fähren, ist aber auf einer Insel.
• • Der User will in eine Fußgängerzone, ist aber ein Kraftfahrzeug.

A route calculation can fail for many reasons. Probably the most common reason for this is that the area around the start or finish point is isolated, ie cut off from the outside world. Apart from errors in the map material, the reasons for this can be found in the profile of the user, for example:

• • The user drives a truck, but wants to enter a locked zone for trucks.
• • The user prohibits ferries but is on an island.
• • The user wants to be in a pedestrian zone but is a motor vehicle.

The present invention describes how an obvious cause as well as the geographical location of this reason for the inaccessibility can be found. In addition, first of all, it is possible to deduce from the procedure how the user would have to change his profile in order to still achieve the goal. Alternatively or additionally, it can be deduced from the method which point near the target could still be reached at the current profile.

The invention further provides for categorizing and sorting the user profiles according to their restrictiveness. In case of a failed route calculation, at least one further route calculation is then started, but with a profile which is somewhat less restrictive than the previous one.

2. State of the art

2.1 Related Methods, Products, and Topics

2.1.1 Related approaches

2.1.1.1 Treatment of a prohibited target or prohibited take-off

The justification of a forbidden goal (or possibly start) is comparatively easy. Only the destination street has to be checked with the current rule set. The one or more individual rules that do not allow the goal are the reasons that the goal is prohibited.

In order to still generate a route for the user, different methods can be used:

2.1.1.1.1 Geometric approach

One way to detect a prohibited destination is to search all roads in the vicinity of the destination. A radius search is started and the street closest to the destination street and not prohibited by the current rule set becomes the new destination.

2.1.1.1.2 directional test

The [1] proposes a method in which a segment-based map database is used for segment-based route planning from a starting point to a destination point. If the target point is an intersection between at least two segments, these intersecting segments are potential target segments. If a segment can now only be driven in one direction away from the intersection because of navigability restrictions, this segment is excluded as a potential target segment in a further step. Thus, an examination of the suitable drivability attributes from a plurality of potential target segments is made here.

2.1.1.2 Detection of an Isolated Start or Target Area

Detecting that a start or target area is isolated is possible regardless of the choice of algorithm. The decision as to whether to isolate the starting or target area can only be made when using two shortest path trees (one around the start and one around the destination point) for at least one of the shortest path trees it is determined that the entire network of streets accessible by the root node has been analyzed without having reached the other tree.

2.1.2 Subject of improvement regarding related approaches

As mentioned, detection and treatment of forbidden start and finish points are already possible with different approaches; as well the detection of isolated starting and target areas is possible. The focus is therefore on the treatment of isolated start and target areas, which is not possible with the two approaches mentioned.

In this case, treatment means providing the user with additional information - where are we unable to get on, why are we not getting any further - and, if necessary, providing a new route.

In addition, the invention presented here offers the possibility of treating different fault scenarios with only one method, it should not be necessary to introduce a separate treatment for each fault scenario.

2.1.3 Reference to related approaches

• [1] Tanimoto, S. (Alpine) Navigation System Having Intersection Routing using a Road Segment based Database, U.S. Patent 5,893,898 , filed 30.7.1996, 2.2 Disadvantages of related approaches

The approach in 2.1.1.1.1 can deal with the fact that the destination or starting road is prohibited; The approach occasionally creates extremely time-consuming suggestions as to where to go instead.

Again, the approach in 2.1.1.1.2 can only be successful if from a given set of start / finish points at least one of the tests of suitable drivability attributes can withstand.

However, none of the related approaches is capable of dealing with isolated target or seed areas, an area that is detected as unreachable farther from the start or destination point.

3. The invention

3.1 problem to be solved by the invention

• • Der User fährt einen Lkw, will aber in eine für Lkws gesperrte Zone.
• • Der User verbietet Fähren, ist aber auf einer Insel.
• • Der User will in eine Fußgängerzone, ist aber ein Kraftfahrzeug.

A route calculation can fail for many reasons. Probably the most common reason for this is that the area around the start or finish point is isolated, ie cut off from the outside world. Apart from errors in the map material, the reasons for this can be found in the profile of the user, for example:

• • The user drives a truck, but wants to enter a locked zone for trucks.
• • The user prohibits ferries but is on an island.
• • The user wants to be in a pedestrian zone but is a motor vehicle.

• • wo genau ist sie gescheitert
• • weshalb genau ist sie gescheitert

The problems here are that the route calculation can register very well, that it has failed, but it is not possible to register in conventional systems:

• • where exactly did she fail?
• • why exactly did she fail?

These two questions can be solved with the present invention.

3.2 Advantages of the invention

• • Es kann ein Verfahren abgeleitet werden, aus dem hervorgeht, wie der User sein Profil verändern müsste, damit er sein Ziel doch noch erreichen kann.
• • Es kann ein Verfahren abgeleitet werden, aus dem hervorgeht, bis wohin in der Nähe des Ziels der User mit seinem derzeitig gewählten Profil doch noch fahren könnte.

In addition to solving the above-mentioned problems, further advantages of the invention are:

• • A method can be derived that shows how the user would have to change his profile so that he can still achieve his goal.
• • A procedure can be deduced which shows where in the vicinity of the target the user with his currently selected profile could still drive.

3.4 Detailed description

A method for operating a system with which a navigation calculation is possible is proposed. The system is at least equipped with a map memory device, an input / output device and a route calculation device, and preferably with a position determination device.

The method is based on the fact that the user of the system via the input device at least one destination 2 (S. 2 ), and the starting location 1 either also entered by the user or determined via the position-determining device. With the route calculation device, access to the map storage device is now attempted, an optimal route according to predefinable criteria, in particular route profiles 3 between starting place 1 and destination 2 to calculate.

The route profiles consist of a set of parameterizations that relate to the route calculation, wherein different sub-profiles may be present, which may relate in particular to the vehicle type, the route strategy or other parameters. In principle, the parameterizations can also be done individually, but it has been found to be advantageous, with increasing number of parameterizations, to combine them into profiles with which a meaningful combination of parameterizations - eg. B. Pedestrians: do not use highways, otherwise ignore one-way streets, shortest route - summarize.

The method is used when the normal route calculation from the start point to the destination point with the given parameterizations, ie in particular the selected profile, is unsuccessful.

3.4.1 Algorithmic environment

It should be left open here which special routing algorithm is used. However, common to the various algorithms is that they construct one or more shortest path trees around one or more roots. This creates an area that represents the geographic area that has already been searched.

• • StVO (u. a.)
• – Einbahnstraßen
• – Abbiegeverbote – Sperrung für bestimmte Fahrzeugtypen
• • Profile (u. a.)
• – Benutzer wünscht keine Benutzung von Fähren
• – Autobahnen verboten
• – Mautstraßen verboten
• • Algorithmische Randbedingungen (u. a.)
• – Kein Absuchen von unwichtigen Straßen weit entfernt von der/den Wurzeln
• – Begrenzter Speicher
• • Kartenfehler (u. a.)
• – Falsch digitalisierte Verbote
• – Einzelne Straßen sind nicht korrekt miteinander verbunden (i. e. hängen in der Luft).

At some links on the edge of this surface (the surface may of course also have holes), the algorithm must not continue searching and thus can not increase the tree and thus the searched surface in these places; the reasons are manifold:

• • StVO (ua)
• - One-way streets
• - Turn off bans - Blocking for certain vehicle types
• • Profiles (ua)
• - User does not want to use ferries
• - Highways prohibited
• - Toll roads prohibited
• • Algorithmic boundary conditions (among others)
• - No searching of unimportant roads far from the roots
• - Limited storage
• • Map error (ua)
• - Wrong digitized prohibitions
• - Some roads are not connected correctly (ie hanging in the air).

It may happen that the searched area can not be increased anymore, before a valid and legal route has been found.

• 1. Isoliertes Startgebiet
• 2. Verbotener Startpunkt
• 3. Isoliertes Zielgebiet
• 4. Verbotener Zielpunkt
• 5. Zu viel Speicher allokiert

What remains is a scanned area and a more or less meaningful error message. In an exemplary implementation of a routing unit with two shortest path trees, one around the start point and one around the destination point, these include the following error messages:

• 1. Isolated starting area
• 2. Forbidden starting point
• 3. Isolated target area
• 4. Forbidden goal point
• 5. Allocated too much memory

1. and 2. have in common that a shortest path tree around the starting point can not continue to grow or is degenerate. 3. and 4. have in common that a shortest path tree around the target point can not continue to grow or is degenerate. At 5. the sum of the memory requirements of both trees has become too large.

Probably the most important error message (because most frequent) is that of the isolated target area (3.). For the sake of simplicity, it will be assumed in the following. For considerations specific to the other error messages, see 3.4.8.2.

Thus, we first assume that the present algorithm constructs a shortest path tree around the target point and aborts that construction if that tree can not grow any further.

3.4.2 Problem

The real problem now is that this information "isolated target area" does not really help the user. The natural next questions he would ask are the why and the where.

As already mentioned. At the edge of our tree we have many reasons why it did not continue. Even if you log all the reasons, you would probably have a few thousand instances of it. Of those few thousand, one would then have to filter out those or those few who are probably the most intuitive. It does not help to take the first reason, because it can be a simple turn-off ban, but it also does not help to take the last one, because it will probably have nothing to do with the intuitive route at all. Likewise, counting or ranking fails because simple turn-offs or one-way streets will normally be the most common.

3.4.3 Objective

For completeness, just a few words about the class of reasons to be detected:
It is assumed that the legislator has considered the creation of the infrastructure and the StVO, and that, in principle, every point on the map must be reachable from any other point of view; if it is not, then algorithmically not much can be done.

The same applies to the digitization of the infrastructure; Here, too, limits are imposed both on the routing algorithm itself and on the method presented here if flawed errors are to be found in digitization.

It is also assumed in the following that the routing algorithm used has the necessary quality and the necessary resources to be able to calculate a path in a graph, provided that it also exists with appropriate suppression of unimportant roads (consideration of exceptions to this assumption in 3.4.8.4).

So it is limited to looking for the reason of the user or rather in the profile chosen by him or in the vehicle chosen by him.

3.4.4 Profile categorization

The basic idea of the method is to categorize the possible user profiles according to their restrictiveness. For the procedure to be applied, it is required that each profile has at most one predecessor that represents a somewhat less restrictive profile.

The result is a directed graph with one or more roots and no cycles (a forest). The definition of a profile in which everything is really allowed makes the forest with several roots a tree with only one root. This common root would then be a common predecessor of all profiles.

An adaptation of the current profile to the less restrictive predecessor profile is referred to below as relaxation.

• • In dieser Realisierung besteht keine Verbindung zwischen dem „Auto ohne Besonderheiten” und dem „Fahrrad”. Dies hat den Hintergrund, dass Fahrräder nicht auf Autobahnen fahren dürfen, und somit nicht nur eine Lockerung der Restriktivität beim Wechsel vom Auto zum Fahrrad auftreten würde.
• • Ein mit gefährlichen Gütern geladener großer Lkw relaxiert sich natürlich auch zu einem kleinen Lkw ohne Besonderheiten. Genauso relaxiert sich ein Auto, welches Mautstraßen und Autobahnen und Fähren verbietet (oder eine Kombination aus den Dreien) zu einem Auto ohne Besonderheiten. Der in der beispielhaft dargestellte Baum stellt diese Zusammenhänge vereinfacht dar.
• • Wie vorher erwähnt, wurde in dieser Realisierung ein Profil definiert, in dem wirklich alles erlaubt ist. Ohne dieses zusätzliche Profil, würde der Baum in zwei Einzelbäume zerfallen mit den Wurzeln „Auto ohne Besonderheiten” und „Fußgänger”.

The categorization in 1 is an example of what such a categorization might look like. At the top left are some truck profiles, in the middle the car profiles and on the right the profiles for non-motorized road users. Of course, this tree can be changed. To emphasize in this particular realization three points:

• • In this realization, there is no connection between the "car without special features" and the "bicycle". This has the background that bicycles are not allowed to drive on motorways, and thus not only a relaxation of the restrictiveness would occur when changing from car to bicycle.
• • Of course, a large truck loaded with dangerous goods also relaxes into a small truck without any special features. Likewise, a car that prohibits toll roads and highways and ferries (or a combination of the three) relaxes into a car with no special features. The Indian exemplified tree represents these relationships simplified.
• • As mentioned before, in this realization a profile has been defined in which really everything is allowed. Without this additional profile, the tree would fall into two single trees with the roots "car without peculiarities" and "pedestrians".

For more information on the different profiles please refer to 3.4.8.1.

3.4.5 Renewed route calculation

The inventive method begins when a route calculation fails. Depending on which profile has been selected, it must be checked in the profile tree which profile represents the predecessor profile of the current one.

Now the route is recalculated but using the profile with the relaxed boundary conditions. Failure of this routing, then you could choose another relaxed profile or finally cancel.

But if the re-routing does not fail, then we know a route 6 , which has come through relatively similar parameters as the first. We know then for sure that somewhere on the new route is a section that was not passable with the first profile, with the second but already. We no longer have any unsearched search area, at the edge of which the first profile has failed, but a path that can be analyzed, as will be described below.

3.4.6 Determining the reason and the place

This path can be searched using the first profile by reapplying the traffic rules of the first profile for each element of the path. We get one or more elements on the path that did not reach the first profile, but the second one already. Thus, we immediately found the "best" reason for the failure of the first routing.

The element which is farthest from the unreachable destination in path length, and which could not be passed according to the rules of the first route calculation but lies on the path of the second, is for the user the intuitively most logical place where he can not get ahead due to his profile ,

The reason can be determined by comparing the two rule sets that underlie the two profiles. For example, if the first profile is a car with prohibited ferries and the second a car without prohibitions, the reason for the failure of the first calculation is to be found in the prohibition of ferries.

In 2 becomes the route of the second route calculation 6 checked with the rule set of the first profile. The dashed elements 4 the left curve 3 are elements on this route that would not be allowed using the original profile. The location where the user gets stuck due to his profile is the lowest element of the dashed elements because it is on the route of the second route calculation and farthest from the destination.

3.4.7 Suggestion of alternative destination and alternative configuration

For the driver, who just wants to be close to his chosen destination with his current profile, one more information is dropped: The element on the path of the second routing, which was last accessible from the first routing, has one more further property: It would be a conceivable, legal and achievable goal for the profile of the first routing. It is not necessarily the closest to the finish, but it is obviously logical, because up to this point, a driver who knows the way with another vehicle or profile would also drive.

This alternative goal is in 2 with the lower star 5 marked.

This destination can therefore be used for a new routing using the first profile. A direct use of the sub-path of the result of the second route calculation 6 (ie, the path from the start to the link that the rule set of the first profile considers impassable) is not recommended because the profiles may well differ in preferences.

Conversely, it is also conceivable that the driver is quite willing to reconsider his configuration again, and that he waives, for example, if necessary, for example, his ban on ferry services. In this case, the user can immediately with the complete path of the second routing 6 to be served.

However, there are cases where an alternative profile is out of the question. A truck driver would like to reluctantly recommend to take a rental car, but rather to choose the alternative destination and to deal with the situation on the ground.

If both options make sense, the user should be asked whether to use an alternative profile or an alternative target.

It is therefore necessary to decide, based on the different profiles examined, which options are offered to the user. In terms of data, these actions could be based on the predecessor relationship between the profiles (the arrows in ). Thus, the arrow small car to car (without peculiarities) could preferably indicate that the user is offered only the option to drive to the last legal destination, while the arrow between "car (ferries prohibited)" to "car (without special features ) "Both the option to go to the last legal destination, as well as the option to take the relaxed profile and yet to allow ferries are offered.

3.4.8 Possible extensions

3.4.8.1 Advanced profile relationships

As mentioned earlier, the categorization is off 1 just a suggestion. Depending on the granularity of the profiles or the desired quality of expertise, the graph can be adapted to the needs.

In 1 For example, the prohibition of toll roads or highways or ferries leads to a car profile without bans. For example, the ban on all three categories could be relaxed into a car profile without prohibition. However, these relations can be refined.

3.4.8.1.1 Gradual refinement

In 3 For example, the prohibition on all three categories is gradually relaxed vertically. However, a unique predecessor is still needed so that the graph can not be symmetrical and, for several potential problem sources, one must first decide on a particular one that will be checked first.

The arrows indicate the problem source being tested. If, for example, all three categories are banned, the first thing to do is to test whether the ban on ferries was the problem by carrying out a further route calculation only with prohibited toll roads and highways.

3.4.8.1.2 Several predecessors

If a profile has several potential problem sources, it was necessary in 3.4.8.1.1 to choose one that was tested first. In the example off 3 Lastingly, this meant that if all three categories were banned, it was first tested against ferries. If the test was positive (ie the second route calculation was successful) it was canceled on the grounds that it was at the ferry.

However, other (just as important) causes may be forgotten. For example, the main routes between Denmark and Sweden are either ferries or the toll bridge near Copenhagen (Öresundsbron). Here are two alternative profiles one with allowed ferries and one with allowed toll roads helpful.

This information can be generated by allowing a profile to have several predecessors (s. 4 ). If the route calculation fails by means of the first profile, a new route calculation must be started with all predecessor profiles. If at least one of these recalculations was successful, the process can be aborted: Any successful recalculation represents a cause of failure of the very first route calculation and a location of that reason.

To stay with the example of Denmark-Sweden: A car profile with forbidden ferries and forbidden toll roads sues at the first calculation of a route from Copenhagen to Malmö. The profile is relaxed to a car profile with forbidden toll roads and to a car profile with forbidden ferries. Both recalculations are successful.

The result of the route's profile with the forbidden toll roads provides the information that among other things the original prohibition of the ferries was problematic and that now a non-ferry-free but toll-free route could be navigated using the ferry between Helsingor and Helsingbor.

The result of the route of the profile with the forbidden ferries provides the information that among other things the original prohibition of the toll roads was problematic and that now a not toll-free but for it ferry-free connection over the Öresundsbron would be available.

Thus, if both recalculations did not fail, there would be two different reasons for the failure of the first route calculation with two suggestions as to how the profile could be changed and two indications of where to go to without changing the profile.

Failure both, so one or more of the already relaxed profiles could be further relaxed or the process is terminated. A theoretical example in which further relaxation would provide new insights would be if the only link between two islands was a ferry and a toll road "in series".

3.4.8.2 Other reasons for the failure of the first route calculation

The other error messages from 3.4.1 can be handled similarly. A prohibited target is a special case of the isolated target.

A lack of memory is usually also an indication that the current profile has not been chosen so happy. Regardless of the particular algorithm chosen, the profile of the user is usually responsible for the algorithm searching too large an area. For example, if the algorithm searches for a route from Tenerife to Madrid without the use of ferries and operates with a shortest path tree around the destination point in Madrid, this tree will very soon have searched a large part of southern and central Europe; until the algorithm just hits its memory limit.

Again, it would be worth trying to repeat the calculation without banning ferries, concluding that there was a ferry there and that the user would come to Tenerife with her should he be willing to ban his ferries to rethink again.

The detection of an isolated start-up area or forbidden start-point is analogous to the detection of an isolated target area using a shortest-path tree around the starting point. However, the recommendations as to what to do in such a case are more limited to modifying the profile (if possible) because the starting point is difficult to move if detected by the position determination unit.

3.4.8.3 Route calculation not failed but problematic

• • Die berechnete Route ist auf den ersten Blick zu lang oder hat eine zu hohe Reisezeit (beispielsweise sei die Routenlänge mehr als dreimal so lang wie die Luftlinie zwischen Start und Ziel). Auch hier könnte eine Relaxation des Profils eine viel bessere Route erzielen, die dann auch als Vorschlag angezeigt wird.
• • Die erste Routenberechnung hat zwar ein Ergebnis erzielt, jedoch hat sie dafür ungewöhnlich viel Speicher veranschlagt. Dies ist ein Indiz dafür, dass das derzeit gewählte Profil sehr restriktiv für die gewählte Aufgabe ist. Möglicherweise ist ein Vergleich mit einer Route, die durch ein weniger restriktives Profil zu Stande gekommen ist, für den User hilfreich.
• • Die erste Routenberechnung hat zu lange gedauert. Auch dies ist ein Indiz dafür, dass das gewählte Profil möglicherweise nicht angemessen war. Auch hier kann eine zweite Berechnung unter weniger restriktiven Umständen dem User von Nutzen sein.
• • Die erste Routenberechnung ist noch nicht abgeschlossen, hat aber bereits bis jetzt unangemessen viel Zeit (z. B. > 1 min) oder Speicher (z. B. > 2 MB) benötigt. In diesem Fall kann es sinnvoll sein, die laufende Berechnung abzubrechen oder zumindest zu pausieren, um zu testen, ob diese Berechnung nicht mit einem gelockerten Profil sehr schnell und sparsam auszuführen wäre.

A failure of the first calculation need not be the only possible trigger for further calculations. Another way to extend the process is to modify the trigger; also conceivable would be:

• • The calculated route is initially too long or too long to travel (for example, the route length is more than three times the distance between the start and finish). Here, too, a relaxation of the profile could achieve a much better route, which is then also displayed as a suggestion.
• • The first route calculation did get a result, but it estimated unusually high memory. This is an indication that the currently selected profile is very restrictive for the chosen task. It may be helpful for the user to compare it to a route that has been created through a less restrictive profile.
• • The first route calculation took too long. Again, this is an indication that the chosen profile may not be appropriate. Again, a second calculation under less restrictive circumstances may be useful to the user.
• • The first route calculation is not yet completed, but it has already taken an inordinate amount of time (eg> 1 min) or memory (eg> 2 MB). In this case, it may be useful abort or at least pause the current calculation to test whether this calculation would not be very quick and economical with a relaxed profile.

3.4.8.4 Vary route type

If the route calculation algorithm used represents a heuristic (and he has to, if he wants to be performant), it may also be helpful to vary the type of route.

If the first route calculation fails or if it is problematic for one of the reasons given in 3.4.8.3, a second attempt with another route type can also achieve a better result. A route type is determined by the general route calculation strategy.

An example of known route calculation engines would be the switching between the route types fast and short route (s. ). To find a fast route, for example, a comparatively large corridor has to be searched, which is compensated for by ignoring the less important roads relatively soon after the start. It may u. It may happen that a very fast direct connection on unimportant roads is overlooked.

For finding a short route, however, the algorithm can assume that it is most likely relatively close to the air-line connection between start and finish, so the corridor is correspondingly narrow and therefore permanently less important roads can be evaluated.

Switching from optimization to travel time to route length optimization may thus produce a result that is both shorter and faster.

The user should, however, in this case, nothing of it, because the fact that an algorithm depending on the settings have to make completely different assumptions, he should have nothing to do.

3.5 New and Modified Parts of the Invention

• None

3.6 Detailed example

The inventive method is explained to the 6 and 7 ,

6 shows a typical procedure.

The method begins with a normal route calculation based on a map database in which the route algorithm is given a starting point and a destination point. Preferably, the starting point is the current position of the vehicle.

If the route calculation is successful, it will continue to be processed normally, i. H. In particular, a route guidance is started, which guides the user along the route to his destination. The inventive method intervenes only when the route calculation was unsuccessful. In principle, a 'unsuccessful' route calculation could also be understood as blurred and include the cases from 3.4.8.3.

The next step is to analyze which reasons are known to the system for the unsuccessful route calculation. If there are reasons as listed in 3.4.1, in particular the isolated target area, which lead to the failure of the route calculation, then the method can continue, otherwise it is preferably branched to a speaking error message and the process is terminated.

If the procedure can be continued, then the current route profile is analyzed next and based on the profile tree used 1 . 3 . 4 the next lower, so less restrictive profile chosen. This will start a new route calculation.

Again, it is now checked whether this is successful, after the o. G. Criteria. If not, the reason for the failure is again checked, because in this case too, other reasons may cause the failure that did not occur with the previously used, more restrictive profile.

If the routing was successful, an analysis of the route just calculated is now performed. Thus it can be identified at which point of the route the first route planning did not progress, because there the determined route violated profile specifications of the first route planning. Depending on the profile setting and the type of result, the user can now be suggested to adjust the profile, to adjust the destination. After the user's decision, the route already calculated is then adopted in the case of a desired adaptation of the profile, or a new route is calculated using the new destination if the destination is adjusted as desired.

A concrete situation for the application of the inventive method is in 7 illustrated.

• • Sie startet die Navigation mit dem Profil mit den verbotenen Fähren und bekommt eine Fehlermeldung mit einem für sie relativ geringen Informationsgehalt

The non-local test subject is in Hamburg and would like to visit a friend on Sylt. In principle, she has forbidden ferries in her profile, as she has previously found that the use of ferries tends to be slower and possibly more expensive than not using ferries. A look at the map has even shown her that there is a thin land connection between the mainland and Sylt.

• • It starts the navigation with the profile with the forbidden ferries and gets an error message with a relatively low information content

Now the test person wonders what this may be: Is it a mistake in the software or an operating error on your part? Maybe she made the settings prohibiting ferries some time ago and can not even remember that she had banned them. And even if she remembers and maybe changed her profile, then she would know that it has anything to do with ferries, but she does not know where a ferry is or why she should take her.

In the worst case, however, she would look at the map and choose a destination near Sylt but still on the mainland. What she does not know: It is a car train (as a ferry digitized, bright in ), which connects Sylt with the mainland. The last possibility to take it is the station of the village Niebüll, which lies twenty kilometers inland.

• • Sie würde die erste Routenberechnung unter Verbot von Fähren wie gewohnt ausführen, jedoch würde sie bei der Detektion des isolierten Zielgebiets keine Fehlermeldung ausgeben.
• • Es wird dann ein Vorgängerprofil des derzeit aktiven gewählt: Das Profil des Autos unter Verbot von Fähren wird relaxiert zu dem Profil des Autos ohne Verbote.
• • Nun wird eine erneute Routenberechnung angestoßen mit letzterem Profil und es wird eine Route gefunden (markiert in der Karte, gestrichelte Linie)
• • Nun wird die gefundene Route Schritt für Schritt gegen das Regelset der ersten Routenberechnung überprüft (von Hamburg nach Sylt) und es würde bei Niebüll die Information liefern, dass hier das erste Regelset eine Weiterfahrt nicht gestatten würde.
• • Bereits hier hätten wir zwei Information für die Testperson, die für sie von Nutzen wären:
• – Das Ziel ist nicht erreichbar, weil Fähren verboten worden sind.
• – Eine Fähre, die das System unter Beachtung des aktuellen Profils benötigen würde, beginnt bei Niebüll.
• – Nun kann das System durch das hier vorgestellte Verfahren noch einen Schritt weiter gehen und Lösungsmöglichkeiten vorschlagen:
• – Entweder akzeptiert die Testperson, dass es ohne Fähren nun einmal nicht geht und entscheidet sich dafür, das vorgeschlagene Alternativ-Profil zu wählen (in diesem Fall das Auto ohne Verbote). Somit könnte die Testperson ihr Fahrzeug gegen Aufpreis mit bis nach Sylt nehmen.
• – Oder die Testperson entscheidet sich, zunächst einmal so nah wie möglich und sinnvoll (!) an ihr Ziel zu gelangen, und wählt das vorgeschlagene Alternativ-Ziel: Das letzte Element auf der Route der zweiten Routenberechnung, welches noch mit ihrem aktuellen Profil erreichbar ist. Dieses Ziel liegt in Niebüll direkt am Bahnhof und eben nicht an der Nordseeküste.
• – Hier angekommen kann sich die Testperson vor Ort ein Bild von der Lage machen. Möglicherweise auch beeinflusst vom Aufpreis einer Fahrzeugmitnahme im Zug, kann sie jetzt entscheiden, ob sie ihr Fahrzeug stehen lassen oder mitnehmen möchte.
• – Sofern vorhanden könnten auch im Kartenmaterial oder via Onlinezugriff abgerufene Informationen über die Fähre, wie Preise, Bedingungen (Autozug/Fähre, oder nur für Fußgänger), Fahrzeiten etc. selektiert und dem Nutzer angezeigt werden.

The software that is equipped with the procedure presented here would instead proceed as follows:

• • It would do the first route calculation prohibiting ferries as usual, but it would not issue an error message when detecting the isolated target area.
• • It then selects a predecessor profile of the currently active: The profile of the car prohibiting ferries is relaxed to the profile of the car without prohibitions.
• • Now a new route calculation is initiated with the latter profile and a route is found (marked in the map, dashed line)
• • Now the route found is checked against the rule set of the first route calculation step by step (from Hamburg to Sylt) and Niebüll would provide the information that the first rule set would not permit a continuation of the journey.
• • Already here we would have two pieces of information for the subject that would be of use to them:
• - The destination is not accessible because ferries have been banned.
• - A ferry, which would need the system under consideration of the current profile, starts at Niebüll.
• - Now the system can go one step further with the presented method and propose solutions:
• - Either the test subject accepts that it will not work without ferries and decides to choose the proposed alternative profile (in this case, the car without prohibitions). Thus, the subject could take their vehicle for a surcharge with up to Sylt.
• - Or the test person decides to get as close as possible and sensible (!) To their destination first, and chooses the proposed alternative destination: The last element on the route of the second route calculation, which is still accessible with their current profile , This destination is located in Niebüll directly at the station and not on the North Sea coast.
• - Once arrived, the test person can get an idea of the situation on site. Possibly also influenced by the surcharge of a vehicle take on the train, she can now decide whether she wants to leave her vehicle or take her.
• - If available, also in the maps or via online access retrieved information about the ferry, such as prices, conditions (car train / ferry, or pedestrians only), travel times, etc. selected and displayed to the user.

Claims (11)

Method for operating a navigation system equipped with at least one card memory device, an input device, a route calculation device and a preferably permanently stored predefinable parameter set for the route calculation, comprising the following steps: a) Determination of a starting point and a destination point b) beginning of a calculation of an optimal route between said start and end point on the map data stored in the map memory means by means of route calculating means using said parameter set c) in the route calculation unit detection of the failure of the route calculation d) automatic modification of the parameter set, in particular in the form of a weakening of road element use restrictions e) recalculation of the optimal route between start and end point by means of route calculation device using the modified parameter set f) upon successful route calculation, analysis of the calculated route on the basis of the first parameter set and detection of the last road element permitted after the first parameter set g) Output of the result to the user. A method according to claim 1, characterized in that the automatic parameter set adaptation in a repeal of blockages for certain types of road, esp. Ferry, toll road, highway or vehicle type-dependent locks exists A method according to claim 2, characterized in that a defined number of parameter sets are stored as profiles. A method according to claim 3, characterized in that the profiles are defined in a preferably hierarchical arrangement, wherein as the hierarchy level increases, the road element usage restrictions become more stringent, the automatic parameter set adaptation consisting in a downgrading of the parameter set profile within the hierarchy. A method according to claim 3, characterized in that the profiles are arranged in a modified hierarchical level, and the automatic adaptation of the parameter combination in step d) consists in that, in the event that a plurality of subordinate profiles exists, more than one of the subordinate profiles in Step e) is used. Method according to one of the preceding claims, characterized in that the user is given the choice in step g) to accept at least between the options the adaptation of the parameter set or alternatively accept the identified last permitted road element as an alternative destination. Method according to one of the preceding claims, characterized in that the user is informed in step g) of the reason for the unsuccessful route calculation, the reason being identified on the basis of the automatic adaptation of the parameter set. The method of claim 1, wherein the failure of the route planning in step c) is detected even if at least one of the following conditions is met: - The length or travel time of the successfully calculated routes is too high in relation to the air distance - A disproportionate amount of storage space was consumed for the route calculation - The duration of the route calculation was too long. A method according to claim 8, wherein it is checked during the route calculation whether one of the criteria has been exceeded and in this case the route calculation is aborted as failed or at least interrupted. Method according to one of the preceding claims, characterized in that in a further failure of the route calculation in step e) in step d), the method is continued, wherein the automatic adjustment is in particular in a further downgrade in the profile hierarchy. Method according to one of the preceding claims, characterized in that the automatic. Adjustment of the parameter set in an adjustment of the route type, especially after the automatic adjustment by means of downgrading in the profile hierarchy was unsuccessful.

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