HK1127396A - Navigation device and method for providing warnings for a speed trap - Google Patents

Abstract

The invention relates to a navigation device for providing warnings when a detection point of a speed trap is approached, comprising a processor unit (11) arranged to communicate with memory unit (12 - 15) and to receive positional information from a positioning device (23). The memory unit (12 - 15) may comprise a speed trap database, comprising at least one detection point (P1) of a location of a speed trap. The navigation device (10) is arranged to provide a warning when one of the at least one detection point (P1) is approached. The memory unit (12 - 15) is further arranged to comprise at least a further detection point (P2) associated with at least one of the stored detection points (P1), both relating to a same point to point speed trap. The navigation device (10) is arranged to provide a warning when the further detection point (P1) is approached or has been passed.

Description

Navigation device and method for providing alarm for speed trap

Technical Field

The present invention relates to a navigation device for providing an alarm when approaching a detection point of a speed trap. The invention further relates to a vehicle comprising the navigation device and a method for providing an alarm when a detection point of a speed trap is approached. Furthermore, the invention relates to a computer program and a data carrier.

Background

The prior art navigation devices based on GPS (global positioning system) are well known and widely used as in-vehicle navigation systems. The GPS-based navigation device relates to a computing device that is functionally connected to an external (or internal) GPS receiver and is capable of determining its global position. Further, the computing device is capable of determining a route between a start address and a destination address, which may be input by a user of the computing device. Typically, the computing device is implemented by software for computing a "best" or "optimal" route between the start address location and the destination address location from a map database. The "best" or "optimal" route is determined based on predetermined criteria and need not necessarily be the fastest or shortest route.

The navigation device may typically be mounted on the dashboard of a vehicle, but may also be formed as part of the onboard computer of a vehicle or car radio. The navigation device may also be (part of) a handheld system, such as a PDA or a phone.

Using position information derived from the GPS receiver, the computing device can determine its position at regular intervals and can display the current position of the vehicle to the user. The navigation device may also include a memory unit for storing map data and a display for displaying selected portions of the map data.

Also, it may provide instructions on how to navigate the determined route by appropriate navigation directions, which are displayed on the display and/or generated as audible signals from a speaker (e.g., "turn left at 100m in front"). Graphics depicting the actions to be completed (e.g., a left arrow indicating a left turn ahead) may be displayed in the status bar, and may also be superimposed over applicable intersections/turns, etc. in the map itself.

It is known to enable in-vehicle navigation systems to allow a driver to initiate route recalculation while driving a car along a route calculated by the navigation system. This is useful in situations where the vehicle is faced with construction work or severe congestion.

It is also known to enable a user to select the kind of route calculation algorithm deployed by the navigation device, for example to choose from a "normal" mode and a "fast" mode (which calculates the route in the shortest time, but does not look at as many alternative routes as the normal mode).

It is also known to allow routes to be calculated with user-defined criteria; for example, a user may prefer a scenic route to be calculated by the device. The device software will then calculate various routes and give more preference to those that include along their route the most points of interest (known as POIs) marked as being, for example, scenic attractions.

From EP 1.266.238, navigation devices are known which comprise a speed trap detection and warning system, which is arranged to alert the driver of a danger (including speed traps). The navigation device may comprise storage means configured to store location data defining the locations of a plurality of speed trap zones. The current position of the navigation device is compared to these positions and depending on the result, the user can be alerted. Such speed trap may for example be a point-to-point speed trap.

It is an object of the present invention to provide an improved speed trap warning system.

Disclosure of Invention

According to an aspect, a navigation device for providing an alarm when approaching a detection point of a speed trap is provided, the navigation device comprising a processor unit and a memory unit, the processor unit being arranged to communicate with the memory unit and to receive location information from a positioning device, the memory unit being arranged to comprise a speed trap database, comprising at least one detection point of a location of a speed trap, wherein the navigation device is further arranged to provide an alert when approaching one of the at least one detection points, characterized in that the memory unit is further arranged to comprise at least further detection points associated with at least one of the stored detection points, both the distant detection point and the associated detection point relate to the same point-to-point speed trap, wherein the navigation device is further arranged to provide an alert when the further point of detection is approached or has been passed. This navigation device provides accurate information to the user about the point-to-point speed trap.

According to an embodiment, the navigation device is arranged to

-providing an alarm as a general speed trap alarm when approaching a detection point without a further detection point being associated with the approached detection point,

-providing an alert as a first point-to-point alert if a distant detection point is associated with a close detection point, and

-providing an alarm as a second point-to-point alarm in case a distant detection point is approached or has been passed. According to this embodiment, the navigation device provides different alerts for different situations, which is advantageous for the user.

According to an embodiment, the navigation device comprises a display and the alert may be a visual alert provided via the display, or the navigation device comprises a speaker and the alert may be an audible alert provided via the speaker, or the alert may be a combination of visual and audible alerts.

According to an embodiment, the navigation device is arranged to provide a speeding alert between the point of detection and the further point of detection if the navigation device detects that the speed of the navigation device exceeds a threshold speed value, the threshold speed value being stored in the memory unit and being associated with the segment between the point of detection and the further point of detection. Such a navigation device provides additional information to the user informing the user that the applicable speed limit may be violated. The velocity may be determined based on position information received from a positioning device.

According to an embodiment, the navigation device is arranged to provide a speeding alert if a current speed of the navigation device exceeds a threshold speed value, or may be arranged to provide a speeding alert if an average speed of the navigation device exceeds a threshold speed value. An average velocity from the first detection point to the current position may be calculated.

According to an embodiment, the navigation device is arranged to calculate the suggested speed. This suggested speed may suggest to the user what speed should be obeyed in order to prevent too fast leaving point-to-point speed trap control zones.

According to another aspect, a vehicle is provided, comprising a navigation device according to the above.

According to another aspect, there is provided a method for providing an alarm when approaching a detection point of a speed trap, the method comprising:

-providing a speed trap database containing at least one detection point of the location of the speed trap;

-providing an alert when one of the at least one detection points is approached, characterized in that

-providing at least one distant detection point associated with at least one of the stored detection points, both the distant detection point and the associated detection point relating to the same point-to-point speed trap;

-providing an alert when approaching or having passed the distant detection point.

According to another aspect, a computer program is provided which, when loaded on a computer arrangement, is arranged to perform the method described above.

According to a further aspect, a data carrier is provided, which contains a computer program according to the computer program described above.

Drawings

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

fig. 1 schematically depicts a schematic block diagram of a navigation device;

figure 2 schematically depicts a schematic view of a navigation device;

FIG. 3 schematically depicts a point-to-point speed trap;

FIG. 4 schematically depicts a flow diagram according to an embodiment; and

fig. 5 schematically depicts a flow chart according to an embodiment.

Detailed Description

Fig. 1 shows a schematic block diagram of an embodiment of a navigation device 10, the navigation device 10 comprising a processor unit 11 for performing arithmetic operations. The processor unit 11 is arranged to communicate with memory units storing instructions and data, such as a hard disk 12, a Read Only Memory (ROM)13, an Electrically Erasable Programmable Read Only Memory (EEPROM)14 and a Random Access Memory (RAM) 15. The memory unit may include map data. Such map data may be two-dimensional map data (latitude and longitude), but may also include a third latitude number (altitude). The map data may further comprise additional information, such as information about gas/gas stations, points of interest. The map data may also include information about the shape of buildings and objects along the road.

The processor unit 11 may also be arranged to communicate with one or more input devices, such as a keyboard 16 and a mouse 17. The keyboard 16 may be, for example, a virtual keyboard provided on the display 18 as a touch screen. The processor unit 11 may further be arranged to communicate with one or more output devices, such as a display 18, a speaker 29, and with one or more reading units 19 to read, for example, a floppy disk 20 or a CD ROM 21. The display 18 may be a conventional computer display (e.g., an LCD), or may be a projection type display, such as a heads-up display for projecting meter data onto an automobile windshield or windshield. The display 18 may also be a display arranged to act as a touch screen, allowing a user to input instructions and/or information by touching the display 18 with a finger.

The speaker 29 may be formed as part of the navigation device 10. In the case where the navigation device 10 is used as an in-vehicle navigation device, the navigation device 10 may use speakers of a car radio, an on-board computer, or the like.

The processor unit 11 may further be arranged to communicate with a positioning device 23, such as a GPS receiver, which positioning device 23 provides information about the position of the navigation device 10. According to this embodiment, the positioning device 23 is a GPS based positioning device 23. It will be appreciated, however, that the navigation device 10 may implement any kind of location sensing technology and is not limited to GPS. It may thus be implemented using other kinds of GNSS (global navigation satellite system), such as the european galileo system. Again, it is not limited to satellite-based position/velocity systems, but may equally be deployed using ground-based beacons or any other kind of system that enables the device to determine its geographic location.

However, it should be understood that more and/or other memory cells, input devices, and read devices known to those skilled in the art may be provided. Further, one or more of them may be physically located remote from the processor unit 11, if desired. The processor unit 11 is shown as one block, however it may comprise several processing units acting in parallel or controlled by one main processor, which may be located remotely from each other, as known to the person skilled in the art.

The navigation device 10 is shown as a computer system, but may be any signal processing system with analog and/or digital and/or software technology arranged to perform the functions discussed herein. It will be appreciated that although the navigation device 10 is shown as multiple components in figure 1, the navigation device 10 may be formed as a single device.

The navigation device 10 may use navigation software, such as that known as a "navigator" from tomtomtomtom ltd (tomtomtom b.v.). The "navigator" software can run on a touch screen (i.e., stylus controlled) pocket PC powered PDA device (e.g., the compaq iPaq) as well as devices with an integral GPS receiver 23. The combined PDA and GPS receiver system is designed for use as an in-vehicle navigation system. Embodiments may also be implemented in any other setting of the navigation device 10, such as a device with an integral GPS receiver/computer/display or a setting designed for non-vehicular use (e.g., for walkers) or vehicles other than automobiles (e.g., airplanes).

Fig. 2 depicts a navigation device 10 as described above.

The "navigator" software, when run on the navigation device 10, causes the navigation device 10 to display a normal navigation mode screen on the display 18, as shown in fig. 2. This view may use a combination of text, symbols, voice guidance, and moving maps to provide driving instructions. Key user interface elements are as follows: the three-dimensional map occupies most of the screen. Note that the map may also be shown as a two-dimensional map.

The map shows the location of the navigation device 10 and its immediate surroundings, which are rotated in such a way that the direction in which the navigation device 10 is moving is always "up". Extending across the bottom quarter of the screen may be a status bar 2. The current position of the navigation device 10 (the navigation device 10 itself is determined using conventional GPS position determination) and its orientation (inferred from its direction of travel) is depicted by a position arrow 3. The route 4 calculated by the device (using a route calculation algorithm stored in the memory units 12, 13, 14, 15 applied to map data in a map database stored in the memory units 12-15) is shown as a darkened route. On the route 4, all major actions (e.g. turning corners, intersections, roundabouts etc.) are schematically depicted by arrows 5 overlaying the route 4. The status bar 2 also comprises at its left side a schematic icon 6 depicting the next action (here, a right turn). The status bar 2 also shows the distance to the next action (i.e. the right turn-here the distance is 190 meters) which is extracted from a database of the entire route calculated by the device (i.e. a list of all roads and related actions defining the route to be taken). The status bar 2 also shows the name of the current road 8, the estimated time to take before arrival 9 (here, 35 minutes), the actual estimated time of arrival 22(4:50pm), and the distance to the destination 26(31.6 Km). Status bar 2 may further show additional information, such as showing GPS signal strength in a mobile phone style signal strength indicator.

As already mentioned above, the navigation device may comprise an input device, such as a touch screen, which allows a user to invoke a navigation menu (not shown). Other navigation functions may be initiated or controlled from this menu. Allowing navigation functions to be selected from a menu screen that is itself very easy to invoke (e.g., one step away from the map display to the menu screen) greatly simplifies user interaction and makes it faster and easier. The navigation menu includes options for the user to enter a destination.

The actual physical structure of the navigation device 10 itself may be substantially indistinguishable from any conventional handheld computer except for the integral GPS receiver 23 or a GPS data feed from an external GPS receiver. Thus, the memory units 12 to 15 store route calculation algorithms, map databases and user interface software; the processor unit 12 interprets and processes the user input (e.g., using the touch screen to input the start and destination addresses and all other control inputs) and deploys a route calculation algorithm to calculate an optimal route. "optimal" may refer to criteria such as shortest time or shortest distance or some other user-related factor.

More specifically, the user uses the provided input devices (e.g., touch screen 18, keypad 16, etc.) to enter their starting location and desired destination into the navigation software running on the navigation device 10. The user then selects the way to calculate the travel route: providing various modes, such as a "fast" mode, which calculates the route very quickly, but the route may not be shortest; a "full" mode, which looks at all possible routes and locates the shortest route, but takes longer to calculate, etc. Other options are also possible, where the user defines a scenic route-e.g. passing through the most POIs (points of interest) marked as superior beauty, or passing through the most POIs likely to be of interest to children, or using the fewest junctions, etc.

The navigation device 10 may further include an input-output device 25 that allows the navigation device to communicate with remote systems, such as other navigation devices 10, personal computers, servers, etc., via a network 27. The network 27 may be any type of network 27, such as a LAN, WAN, Bluetooth, the Internet, an intranet, or the like. The communication may be wired or wireless. The wireless communication link may, for example, use RF signals (radio frequency) and an RF network.

The roads themselves are described in the map database as part of (or otherwise accessed by) the navigation software running on the navigation device 10 as lines-i.e., vectors (e.g., start point, end point, direction of a road, with an entire road being made up of hundreds of such sections, each uniquely defined by start/end point direction parameters). A map is then a set of such road vectors, plus points of interest (POIs), plus road names, plus other geographic features, such as park boundaries, river boundaries, etc., all defined in terms of vectors. All map features (e.g., road vectors, POIs, etc.) are defined in a coordinate system corresponding to or related to the GPS coordinate system, enabling the device location determined by the GPS system to be located onto the relevant road shown in the map.

Route calculation uses complex algorithms as part of the navigation software. The algorithm is applied to score a large number of potentially different routes. The navigation software then evaluates them against user-defined criteria (or device defaults), such as full mode scanning, with scenic routes, past museums, and no speed camera. A route that best meets the defined criteria is then calculated by the processor unit 11 and then stored in a database in the memory units 12-15 as a sequence of vectors, road names and actions to be completed at the vector end points (e.g., corresponding to a predetermined distance along each road of the route, such as turning left into street x after 100 meters).

As already mentioned above, the memory units 12 to 15 may comprise map data. The map data may contain additional information, such as information about gas/petrol stations, points of interest. The map data may also include information about the location of speed trap (e.g., point-to-point speed trap).

Point-to-point automobile overspeed monitoring area

The point-to-point speed trap PP is a speed trap comprising a first inspection point P1 and a second inspection point P2, as schematically depicted in fig. 3. These points may also be referred to herein as detection point P1 and farther detection point P2, respectively.

The distance X between the first detection point P1 and the second detection point P2 is known, for example 3500 meters. The point-to-point speed trap PP is arranged to detect vehicles V driving past the first detection point P1. All kinds of techniques can be used to detect the vehicle V driving past the first detection point P1. The vehicle V may be detected, for example, using an electromagnetic sensor (not shown) provided in the road. If the vehicle V is detected, the first camera CA1 positioned at the first detection point P1 is caused to photograph the vehicle V, for example, photograph the number plate of the vehicle V.

The point-to-point speed trap PP may further comprise a processing unit 90. The processing unit 90 may be any type of computer system including, for example, an input device 91, a memory unit 92, and a processor 93. The processor 93 is arranged to communicate with the memory unit 92 and the input device 91.

A picture taken by the first camera CA1 at the first detection point P1 is transmitted to the memory unit 92 via the input device 91. Pictures taken by the first camera CA1 may be transmitted to the processing unit 90 using any kind of technology (e.g., simple wires) and also via any kind of network (e.g., wired or wireless network). The time t1 (e.g., 10:30:23) at which the picture was taken is also stored in the memory unit 92.

The vehicle V is detected in a similar manner when it drives past the second detection point P2. Likewise, the camera CA2 positioned at the second detection point P2 is caused to take a picture of the vehicle. The picture taken at the second detection point P2 is stored in the memory unit 92 of the processor unit 90 together with the time t2 (e.g., 10:32:10) at which the picture was taken.

Of course, there may be many vehicles driving through the point-to-point speed trap PP per minute. Thus, all pictures stored in the memory unit 92 are analyzed and pictures showing the same vehicle at the first and second detection points P1 and P2 are grouped together, e.g., based on the number plate.

Next, the processor 93 calculates the average speed of the vehicle V between the first and second detection points P1, P2 based on the time values of t1 and t2 showing the first and second pictures of the same vehicle V and the known distance X between the first and second detection points P1, P2. In this case, the average speed of the vehicle V is:

since 10:32:10 minus 10:30:23 equals 107 seconds. Next, this calculated v may be compared_AverageCompared to a threshold speed value stored in memory unit 92. The threshold speed value may correspond to a maximum speed of the road segment between detection point P1 and detection point P2. For example, where the highest speed for the segment is 100km/h, the threshold speed value may be 100km/h or 103 km/h. At v_Average＞v_{Threshold value}The owner of the vehicle V may be penalized.

According to the prior art, a speed trap warning system provides a warning when a user approaches a speed trap. The alarm is generated if the navigation detects that the navigation device 10 is approaching an speed trap, the location of which is stored in a database accessible to the navigation device 10. Most speed trap systems are single independent systems. For such independent speed trap it is sufficient to provide an alarm indicating the approach of the speed trap. The driver can slow down their vehicle and will not be penalized or receive a ticket afterwards.

In the point-to-point speed trap, the average speed between the first and second detection points P1, P2 is calculated. Thus, if the user accelerates his vehicle after having passed the detection point P1 (as described above), he is at risk of being penalized by driving too fast because the average speed between the first and second detection points P1, P2 is too high.

Example 1

According to an embodiment, the memory units 12 to 15 of the navigation device 10 may be arranged to include information about the location of the point-to-point speed trap PP, i.e. information about the first detection point P1 at the first position L1 and the second detection point P2 at the second position L2. Also, information may be stored indicating that the first and second detection points P1, P2 are associated with each other and are part of the same speed trap, i.e. the point-to-point speed trap PP.

The navigation device 10 may be arranged to provide a first alert or information signal to the user when the user approaches the first detection point P1. The alarm or informational signal may tell the user that he is entering a point-to-point speed trap control area.

This first alert may be a clear audio or verbal message played via speaker 29, and/or a visual alert, such as an icon displayed at display 18.

The navigation device 10 may further be arranged to provide a second alert or information signal to the user when the user has passed the second detection point P2. The alarm or information signal may tell the user that he has left the point-to-point speed trap control area.

Again, this second alert may be a clear audio or verbal message played via speaker 29, and/or a visual alert, such as an icon displayed at display 18.

According to a variant, the first alarm may be displayed until the navigation device 10 has left the point-to-point speed trap control area, for example in case the first alarm is at least a visual alarm. In that case, the second alarm is given in effect by no longer providing the first alarm.

This feature helps users to prevent being penalized or legally penalized by the fact that they are not aware that they are accelerating in the point-to-point control area of the road. Also, this helps to increase traffic safety in the area by constantly informing the driver of the area.

According to this embodiment, the navigation device 10 provides an alert that the alert content is that a point-to-point speed trap control area has been entered and therefore the user should not accelerate their vehicle after having passed the first detection point P1.

By storing the first inspection point P1 and the second inspection point P2, the user can be given accurate information about the location of the point-to-point speed trap PP. When approaching the point-to-point car overspeed monitoring zone, a warning can be given to the user so when approaching the first point P1 of the point-to-point car overspeed monitoring zone PP, but also when exiting the point-to-point car overspeed monitoring zone PP, i.e. when having passed the second inspection point P2. Based on this embodiment, the user knows exactly whether it is inside or outside the point-to-point speed trap control area.

According to the prior art, as stated above, the current navigation device 10 gives an alarm when a user approaches a speed trap (e.g. a point-to-point speed trap). However, no indication is provided as to what type of speed trap is approached and no warning is given when leaving the area controlled by the point-to-point speed trap.

Based on this embodiment, the user will know that he should not accelerate his vehicle when having passed the first detection point P1 and that he should comply with the applicable highest speed value until he has left the point-to-point control area, so until when he is given an alarm or information signal informing that he has left the point-to-point control area.

Based on this embodiment, the memory units 12-15 of the navigation device 10 may be arranged to store a speed trap database that is improved over the prior art. The speed trap database stores not only the first inspection point P1 together with the location of the speed trap, but also a second inspection point P2 associated with at least one of the stored first inspection points P1, indicating that the first inspection point P1 refers to a point-to-point speed trap ending on the second inspection point P2.

Memory cells 12-15 may, for example, include the following information:

database for overspeed monitoring area of automobile	First detection point P1	Second detection point P2
			1	X1，Y1	-
2	X2，Y2	X2，2，Y2，2
			3	X3，Y3	-
4	X4，Y4	X4，2，Y4，2
			5	X5，Y5	-

According to this example, the speed trap database includes five entries. The first automobile overspeed monitoring area is positioned at a first position X₁，Y₁Wherein X is_iAnd Y_iCoordinates representing the ith speed trap. It will be appreciated that many ways of indicating the location of the speed trap may be used, and X₁，Y₁But merely as examples of such representations. The first speed trap may be any type of speed trap, such as a laser speed trap, a radar speed trap, etc.

The second speed trap stored in the speed trap database refers to a point-to-point speed trap. This can be inferred because of the first position X that follows₂，Y₂And then storing the first position X₂，Y₂Associated second position X_2，2，Y_2，2. First position X₂，Y₂A first inspection point P1 representing a point-to-point vehicle overspeed monitoring area PP, and a second position X_2，2，Y_2，2Indicating point-to-point automobile overspeed monitoring areaSecond detection point P2 of PP.

According to this example, in general, the first location X_i，Y_iA first inspection point P1 representing a point-to-point vehicle overspeed monitoring area PP, and a second position X_i，2，Y_i，2A second inspection point P2 representing a point-to-point car speed trap PP.

Therefore, additional information is added to the speed trap database, which indicates that a particular speed trap is a point-to-point speed trap. The software may be arranged to read this information and provide an alert informing the user of the entry or imminent entry point into the point-to-point control area, and also to inform the user when the user has left or is about to leave the point-to-point control area.

Flow diagram example 1

According to this embodiment, the navigation device 10 may be arranged to perform the actions as presented below and depicted in the flow chart of fig. 4.

In a first action 101, the navigation device 10 may be arranged to determine whether a speed trap is approached. This can be done in many ways, as the skilled person will appreciate. When determining whether an speed trap is approached, the navigation device 10 may take into account the distance to the speed trap, the direction of travel of the navigation device 10, the direction in which the speed trap is oriented, the road segment on which the speed trap is located, the road segment on which the navigation device 10 is traveling, etc. stored in the speed trap database, as will be appreciated by the skilled person. It will be appreciated that additional information may be stored in the speed trap database to allow such an assessment according to act 101. For performing action 101, the navigation device 10 may use information from the speed trap database and the positioning device 23 stored in the memory units 12-15, as schematically depicted in fig. 4.

Without approaching the speed trap, the navigation device 10 may repeat act 101. In the case of approaching a speed trap, the navigation device 10 may be inIn act 102 it is determined what type of speed trap is approached. This may be done by reading out information about the speed trap type from a speed trap database stored in the memories 12 to 15. According to the example provided above, this is done by checking the second position X_i，2，Y_i，2Whether or not to store the first position X in an approaching speed trap_i，Y_iThe associated storage is done in the speed trap database in the memories 12 to 15.

In case the approaching speed trap is not a point-to-point speed trap, the navigation device 10 may continue to perform act 103, wherein an alarm, such as a general speed trap alarm, is generated. This alarm may be any type of alarm, such as an audible alarm provided via speaker 29.

In case the approaching speed trap is a point-to-point speed trap, the navigation device 10 may continue to perform act 104, wherein a first point-to-point alarm is generated. This alarm may be any type of alarm, such as an audible alarm provided via speaker 29. The first point-to-point alert may be different from the alert generated in act 103 to inform the user that the point-to-point speed trap is being approached, so the user may adapt his driving behavior based thereon.

Once the point-to-point alarm is generated, the navigation device 10 proceeds to perform act 105, wherein it is determined whether the navigation device 10 has passed the first location X with the speed trap_i，Y_iAssociated second position X_i，2，Y_i，2. As long as the second position X has not been passed_i，2Y_i，2The navigation device repeats act 105.

Once having passed the second position X_i，2，Y_i，2The navigation device 10 provides a second point-to-point alert. Again, this second point-to-point alarm may be any type of alarm, such as an audible alarm provided via speaker 29. The second point-to-point alert may be different than generating the second point-to-point alert in act 103And the first point-to-point alert generated in act 104 to inform the user that the point-to-point control area has been left, the user may adapt his driving behavior based thereon.

The first point-to-point alert may be a verbal message telling the user that "you are about to enter the point-to-point control area of the road" and the second point-to-point alert may be another alert, for example telling the user that "you have left the point-to-point control area". The first and second point-to-point alarms may also be two distinct sounds or tones.

Of course, all alarms may also be visual alarms provided via the display 18, or a combination of visual and audible alarms.

The navigation device 10 may also be arranged to provide a "permanent" alert which constantly informs the user that it is in the speed control area. For example, where the alert is a visual alert displayed via the display 18, the alert may continue to be displayed until the second location X has been passed_i，2，Y_i，2Until now. Thus, the second point-to-point alarm may simply be to stop providing the first point-to-point alarm.

Example 2

According to a second embodiment, the navigation device 10 may further be arranged to provide an overspeed warning between the first detection point P1 and the second detection point P2 in case the navigation device 10 detects that the user is speeding, i.e. violating a speed limit applicable for the particular road segment.

For example, a speeding alert may be generated if the speed of the navigation device 10 (i.e. vehicle), such as determined based on information received using the positioning device 23, exceeds a threshold speed value stored in the memory unit 12-15 of the navigation device 10.

According to another example, a speeding alert may be generated if the average speed of the navigation device 10 (i.e. vehicle), e.g. determined based on information received using the positioning device 23, exceeds a threshold speed value stored in the navigation device 10.

In both examples, the threshold speed value stored in memory units 12-15 may correspond to the highest speed of the road segment between detection point P1 and detection point P2. For example, where the highest speed for the segment is 100km/h, the threshold speed value may be 100km/h or 103 km/h.

According to a first example, the navigation device 10 continuously checks the current speed of the vehicle by comparing successive measurements of the positioning device 23, as is typically done continuously in the navigation device 10. An overspeed warning may be provided when the determined speed exceeds a threshold speed value associated with the road segment and stored in memory units 12-15.

According to a second example, the average speed of the navigation device 10 between the first and second detection points of the point-to-point speed trap PP is determined and compared to a threshold speed value. To do this, the navigation device 10 may be arranged to calculate an average speed of the navigation device 10 at least at a particular location or constantly within a point-to-point speed trap control area and compare this average speed to a threshold speed value associated with the road segment and stored in the memory units 12-15.

So, after entering the point-to-point speed trap control area, the navigation device 10 may be arranged to start calculating the average speed of the navigation device 10 between the first detection point and the current position. If the average speed exceeds the threshold speed value, the navigation device 10 may periodically provide a speeding alert.

It will be appreciated that a combination of the two examples given above may also be employed, i.e. the navigation device 10 may be arranged to determine the current speed of the navigation device 10 as the average speed and simultaneously compare these speeds to the threshold speed value. If one of the current/average speeds is above the threshold speed value, the navigation device 10 may periodically give a speeding alert. This speed alarm may be a clear audio or verbal message played via speaker 29, and/or a visual alarm, such as an icon displayed at display 18. In case the speeding alert is a spoken speeding alert, the spoken alert may for example be "you are still in the point-to-point control area, you are driving too fast" or "you are still in the point-to-point control area, you are driving too fast. The speed limit for this area is 100km/h ".

Average speed indication

The overspeed warning can be a current speed indication or an average speed indication and can be given periodically throughout the point-to-point control region. By using a so-called adaptive scheme, the period of the overspeed alarm can be 5 to 20 seconds depending on the extent to which the speed limit is exceeded. The average speed indication may also be given constantly, i.e. it may be updated for each new position received from the positioning device 23.

For example, if the driver is driving too fast, a warning may be provided early in the point-to-point control region to give the driver time to correct the overall average speed. If, on the other hand, the driver does not overspeed much, it is not necessary to disturb the warnings too frequently or early in the point-to-point control area.

The navigation device 10 may be arranged to display an average speed indication informing the user of the average speed between the first detection point P1 and the second detection point P2 from the first detection point P1 to the current position. This average speed indication may be calculated by continuously calculating the average speed up to this point, using as input the time that has passed the first detection point, the position of the first detection point P1, the current time and the current position. The average speed indication may be updated approximately every second.

In conjunction with the average speed indication, the target average speed may be displayed, for example, as a speed limit for the point-to-point control area or a threshold speed value associated with the point-to-point control area.

Furthermore, in combination with the average speed indication, a suggested speed v may be displayed_AdvisingThereby informing the driver of the suggested speed. This suggested velocity v when entering a point-to-point_AdvisingMay be a speed limit for a point-to-point control area or a threshold speed value v associated with a point-to-point control area_{Threshold value}. However, during the travel from the first detection point P1 to the second point P2, the suggested velocity v is_AdvisingMay change due to the driving behavior up to this point.

For example, halfway through a point-to-point control area where the navigation device 10 detects that it is and the average velocity so far exceeds the threshold velocity value v_{Threshold value}In case of (2), the suggested speed v is selected_AdvisingSo that the user follows the suggested speed v_AdvisingIn the case of (2), the average velocity v at the end of the point-to-point control region_AverageDoes not exceed the threshold velocity value v_{Threshold value}。

The suggested time t at which the navigation device 10 will pass the second detection point P2 may be calculated by first calculating the suggested time t_AdvisingTo calculate a suggested velocity v_AdvisingThe suggested time t_AdvisingCan be calculated as:

wherein t is₁Is the time taken to pass the first detecting point P1, X is the distance between the first and second detecting points P1, P2, and v is_{Threshold value}Is a threshold speed value associated with a particular point-to-point speed trap.

Suggested velocity v_AdvisingCan be calculated as:

wherein t is_Advising＞t_{At present}And wherein L_{At present}Is the current position, L, of the navigation device, as measured by the positioning device 23₂Is the position of the second detection point P2, t_{At present}Is whenThe previous time. At t_Advising＜t_{At present}The speed of the navigation device 10 is relatively slow. To prevent negative suggested velocities v_AdvisingIf t is_Advising＜t_{At present}No further alarm is required.

Of course, all alarms and indications may also be provided as audible messages via the speaker 29.

When the user is at a velocity v equal to the threshold velocity_{Threshold value}The suggested speed v is compared to the case of extremely slow or extremely fast driving_AdvisingMay be very high or very low, respectively. To prevent the provision of suggested speeds that conflict with law, v may be_AdvisingCompared to upper and/or lower speed limits for the proposed speed. The upper speed limit may be the same as the speed limit or threshold speed and the lower speed limit may correspond to the lowest allowable speed according to law. This check may be made as part of act 107.

The suggested speed may be provided to the user by a suggested speed indication, which may be passive or silent, such as an icon in a corner of the display 18.

Flow chart example 2

Fig. 5 schematically depicts a flow chart according to the second embodiment. Fig. 5 is similar to fig. 4, except for the fact that an additional action 107 is provided between actions 104 and 105.

Once action 104 is completed, the navigation device 10 may start the overspeed warning procedure. As explained above, such an overspeed warning procedure may include comparing the current speed to a threshold speed value and/or comparing the average speed to a threshold speed value.

OTHER EMBODIMENTS

According to a further embodiment, a navigation device 10 is provided for providing an alert when a detection point of a speed trap is approached, the navigation device 10 comprising a processor unit 11 and memory units 12 to 15, the processor unit 11 being arranged to communicate with the memory units 12 to 15 and to receive location information from the positioning device 23, the memory units 12 to 15 being arranged to comprise a speed trap database comprising at least one detection point P1 of a location of the speed trap, wherein the navigation device 10 is further arranged to provide an alert when one of the at least one detection point P1 is approached, wherein the navigation device 10 is arranged to provide an overspeed alert from the detection point P1 in case the navigation device 10 detects that the speed of the navigation device 10 exceeds a threshold speed value, which is stored in the memory units 12 to 15.

This navigation device 10 provides an overspeed warning when in the control area. Also, the navigation device 10 may be arranged to first check whether the speed trap is a point-to-point speed trap.

According to a variant, the speed is determined on the basis of position information received from the positioning device 23.

According to a variant, the navigation device is arranged to provide a speeding alert if the current speed of the navigation device 10 exceeds a threshold speed value.

According to a variant, the navigation device 10 is arranged to provide a speeding alert if the average speed of the navigation device 10 exceeds a threshold speed value. An average velocity from the first detection point to the current position may be calculated.

According to a variant, the navigation device 10 is arranged to calculate the suggested speed v_Advising. This suggested speed may suggest to the user what speed should be followed in order to prevent an excessively fast departure from the point-to-point speed trap control area.

According to a variant, the memory unit 12-15 is further arranged to include at least one farther detection point P2 associated with at least one of the stored detection points P1, both the detection point P1 and the farther detection point P2 relating to the same point-to-point speed trap, wherein the navigation device 10 is further arranged to stop providing speed warnings when the farther detection point P2 is approached or has been passed. The navigation device may further be arranged to provide an alert when approaching or has passed the far detection point P2.

The embodiments described above may be used for all kinds of navigation devices 10, such as portable, handheld, built-in navigation devices 10. Of course, the embodiments may also be used in a vehicle's on-board computer or as part of a car radio system.

While specific embodiments of the invention have been described above, it will be appreciated that the invention may be practiced otherwise than as described. For example, the invention may take the form of a computer program containing one or more sequences of machine-readable instructions describing a method as disclosed above, or a data storage medium (e.g. semiconductor memory, magnetic or optical disk) having such a computer program stored therein. Those skilled in the art will appreciate that all software components may also be formed as hardware components.

The above description is intended to be illustrative, and not restrictive. Accordingly, it will be apparent to those skilled in the art that various modifications may be made to the invention as described without departing from the scope of the appended claims.

Claims (20)

1. A navigation device for providing an alarm when approaching a detection point of a speed trap,

the navigation device (10) comprising a processor unit (11) and a memory unit (12-15), the processor unit (11) being arranged to communicate with the memory unit (12-15) and to receive position information from a positioning device (23),

the memory unit (12-15) is arranged to comprise a speed trap database comprising at least one detection point (P1) for the location of a speed trap,

wherein the navigation device (10) is further arranged to provide an alert when one of the at least one detection points (P1) is approached,

characterized in that the memory unit (12-15) is further arranged to include at least one farther detection point (P2) associated with at least one of the stored detection points (P1), both the farther detection point (P2) and the associated detection point (P1) relating to the same Point-to-Point speed trap,

wherein the navigation device (10) is further arranged to provide an alert when approaching or having passed the distant detection point (P2).

2. Navigation device according to claim 1, wherein the navigation device (10) is arranged to

Providing an alarm as a general speed trap alarm when approaching the detection point (P1) without a farther detection point (P2) being associated with the detection point (P1) being approached,

providing an alert as a first point-to-point alert if the farther detection point (P2) is associated with the detected point (P1) that is close, an

Providing an alert as a second point-to-point alert in the event that the farther detection point (P2) is approached or has been passed.

3. Navigation device according to any one of the preceding claims, wherein the navigation device comprises a display (18) and the alert may be a visual alert provided via the display (18).

4. Navigation device according to any one of the preceding claims, wherein the navigation device comprises a speaker (29) and the alert may be an audible alert provided via the speaker (29).

5. The navigation device of claims 3 and 4, wherein the alert may be a combination of a visual alert and an audible alert.

6. Navigation device according to any one of the preceding claims, wherein the navigation device (10) is arranged to provide a speeding alert between the detection point (P1) and the farther detection point (P2) if the navigation device (10) detects that the speed of the navigation device (10) exceeds a threshold speed value,

the threshold speed value is stored in the memory unit (12-15) and is associated with a segment between the detection point (P1) and the farther detection point (P2).

7. Navigation device (10) according to claim 6, wherein the velocity is determined based on position information received from the positioning device (23).

8. Navigation device (10) according to any of claims 6-7, wherein the navigation device is arranged to provide a speeding alert if a current speed of the navigation device (10) exceeds the threshold speed value.

9. Navigation device (10) according to any of claims 6-8, wherein the navigation device (10) is arranged to provide a speeding alert if an average speed of the navigation device (10) exceeds the threshold speed value.

10. Navigation device (10) according to claim 9, wherein the navigation device (10) is arranged to calculate a suggested speed (v |)_Advising)。

11. A vehicle comprising a navigation device (10) according to any one of the preceding claims.

12. A method for providing an alert when a detection point of a speed trap is approached, the method comprising:

providing a speed trap database comprising at least one detection point (P1) for the location of the speed trap,

providing an alert when one of the at least one detection points (P1) is approached,

is characterized in that

Providing at least one farther detection point (P2) associated with at least one of the stored detection points (P1), the farther detection point (P2) and the associated detection point (P1) both relating to the same point-to-point speed trap,

providing an alert when approaching or having passed the distant detection point (P1).

13. The method of claim 12, wherein the method further comprises:

providing an alarm as a general speed trap alarm when approaching the detection point (P1) without a farther detection point (P2) being associated with the detection point (P1) being approached,

providing an alert as a first point-to-point alert if the farther detection point (P2) is associated with the detected point (P1) that is close, an

Providing an alert as a second point-to-point alert in the event that the farther detection point (P2) is approached or has been passed.

14. The method of any one of claims 12-13, wherein the method further comprises

Providing an overspeed warning between the detection point (P1) and the farther detection point (P2) in case it is detected that a speed of a navigation device (10) exceeds a threshold speed value, the threshold speed value being associated with a road segment between the detection point (P1) and the farther detection point (P2).

15. The method of claim 14, wherein the velocity is determined based on position information received from a positioning device (23).

16. The method according to any one of claims 14-15, wherein an overspeed alarm is provided if a current speed exceeds the threshold speed value.

17. Method according to any of the claims 14-16, wherein a speeding alert is provided if an average speed of the navigation device (10) exceeds the threshold speed value.

18. Method according to claim 17, wherein a suggested velocity (v) is calculated_Advising)。

19. A computer program, which, when loaded on a computer arrangement, is arranged to perform the method of claim 18.

20. A data carrier containing a computer program according to claim 19.