Patent Application
20120283942
None.
1. Field of the Invention
The present invention relates to a navigation system, and more particularly to a method and system for taking into account the speed of a vehicle traveling along a road segment and providing an acoustic, haptic, visual or other warning or recommendation to the vehicle driver when nearing a merging region with another road segment.
2. Related Art
In the current field of Personal Navigation Systems (PNAV) like dedicated handheld navigation systems, Personal Digital Assistants (PDAs), and mobile telephones provided with a navigation module, as well as in the in-car navigation market, end-user needs are already commonly addressed by applications. Vendors differentiate by adding additional functions and features to navigation (and ADAS systems). Examples include speed camera information, traffic information etc. as well as, Junction Views. Junction Views are a feature of some navigation systems that improve guidance and user understanding of crossings, bifurcations or junctions. Such additional features of navigation systems may assist the user in taking the correct decisions when traveling from a starting location to a destination. One approach is to display a junction of, for instance, a highway on the display screen of the navigation system in the car together with all lanes and signposts as are present in reality. Superimposed on or in addition to such a real or animated view are one or more arrows indicating the route to be followed by the driver to his destination and as calculated by the navigation system, or perhaps the route which is likely to be followed by the driver in case the routing function in the navigation system is not (yet) active. Reference is, e.g., made to EP-A-1,681,537 and EP-A-1,681,538.
However in real life situations, the driver has to frequently navigate complex freeway mergers where the driver has to determine a safe merging speed during a very quick comparison between traffic flow conditions as observed through the windows and windscreen. The time necessary for this comparison may be too long possibly resulting in too low attention of the driver for the real life environment which may be dangerous. Also, obstructions such as vegetation or construction equipment can obscure a complete view of the merging traffic conditions, not to mention environmental effects such as adverse weather and poor lighting conditions.
In urban areas, there are frequently many highway entries, lane merging situations and exits. Sometimes, the junction between two road segments is very short, and can unexpectedly lead to severe braking or the need for acceleration to allow the safest possible merge with the adjoining traffic flow. Particular areas of concern, e.g., where two road segments merge into one, will include gas stations on the motorway, parking and rest areas on the motorway, highway entry following a junction, junctions with merging lanes, sudden lane ends as when a motorway reduces from 4 to 3 lanes, temporary construction works, highway mergers, and the like. Merging with another traffic flow can be a very stressful driving maneuver if the driver does not know the particular section of roadway.
There is therefore a need for a navigation system and method that is capable of providing a driver with a merging speed behavior recommendation, allowing the driver to focus on safely merging with another traffic flow at the safest possible speed or acceleration. Furthermore, in condition of moderate and heavy traffic flow, there is a need to assist drivers to leave a safe gap or inter-vehicle distance for vehicles merging into the main lane even if the driver cannot clearly see the merging traffic flow or the end of the merging region. In addition, vehicles can be reminded to create more space in merging lanes by changing lane to the adjacent lane, where vehicle are not merging.
This invention relates to a navigation system of the type to be carried in a vehicle for providing its driver with navigation information. The navigation system comprises a processor, a device operatively connected to the processor for producing audible, visual and/or haptic information, and a determination device operatively connected to the processor for determining a speed and position of the navigation system relative to a road network comprising at least two road segments that merge at a common junction or merger point. A computer program is executed by the processor. The computer program comprises instructions and data in order to allow the processor to communicate the average speed of surrounding vehicular traffic proximate the junction by audible, visual or haptic means.
According to another aspect of this invention, a method provides a vehicular driver with navigation information pertaining to merging traffic conditions. The method comprises the steps of: providing a road network having first and second road segments that merge at a downstream merger point, transporting a navigation system in a vehicle traveling the first road segment, determining a position and speed of the vehicle relative to the road network, and when approaching the junction, communicating the average speed of traffic on the second road segment, or to give more general indications such as by visual or haptic means. In the most general sense, the first road segment can be a main road and the second road segment a merging lane, or vise-versa, or both the first and second road segments can be main roads.
The invention provides beforehand information about average speed of merging traffic. In advanced implementations of the invention, traffic density information can also be provided to assist a driver on a main road to leave a safe gap for vehicles merging into their lane even if the driver cannot clearly see the merging traffic flow or the end of the merging region. A still further embodiment of this invention provides an early warning for the end of lane (e.g. when there is no shoulder lane available, leading to the situation that the merging vehicle may need to stop at the end of the lane. This information, communicated well in advance, will help the driver to make more adequate merging behavior decisions. In another embodiment, the driver is invited to move to another lane, to make space for merging situations ahead.
Using the system and method of this invention, a driver is forewarned of merging traffic speed conditions. Thus, where two road segments merge into one, such as at highway on-ramps, off-ramps, lane reductions, motorway mergers and the like, a driver is notified of traffic speed on the other road segment upstream of the merger point, thereby reducing the need for severe braking or acceleration when mixing with the traffic flow at the point of merger. Merging with another traffic flow is made less stressful, particularly in roadway sections which may be unfamiliar to the driver or at times when visibility is impaired.
The invention covers the lane merging assistance/warning for a variety of situations, including vehicles coming from the merging lane (i.e., providing guidance to accelerate/decelerate to a merging speed ahead; warning for the end of the lane including a potential warning to stop as the end of the lane is reached; as well as lane merging assistance/warning for vehicles on the main road, indicating the merging traffic and asking to adjust speed, keep distance (leave a gap to allow the vehicles to merge and change lane prior to arriving at the merge area allowing other vehicles in the merging area to more efficiently merge. The invention is applicable to any roadway type, including but not limited to motorways and secondary roads (70 and 80 km per hour roads).
These and other features and advantages of the present invention will become more readily appreciated when considered in connection with the following detailed description and appended drawings, wherein:
The present invention is applicable in all kinds of navigation systems; including but not limited to handheld devices, PDAs, and mobile telephones with navigation software and in-car navigation systems built in a vehicle. The invention can be implemented in any type of standard navigation system available on the market. In order to better understand the present invention, below, the application in one possible in-car navigation system will be further explained in detail. However, this does not exclude any other type of implementation, for instance, a handheld device.
Based on the signals received from the GPS system 16, the microprocessor 22 determines suitable display signals to be displayed on a display 24 in the vehicle 10, informing the driver where the vehicle 10 is located relative to a road network, generally indicated at 26, and possibly in what direction it is traveling. Moreover, in the context of the present invention, the microprocessor 22 is programmed with route planning software to calculate a route for the driver of the vehicle 10 from a starting location to a desired destination. Such a desired destination is, for instance, input by a driver via a keyboard 28, touch screen, or other interface which is connected to the microprocessor 22. The keyboard 28 can also be used by the driver to ask the microprocessor 22 to show other information as is known to persons skilled in the art. Instead of a keyboard 28, any alternative device used by the driver to communicate with the microprocessor 22 can be used, like a touch screen or a voice convertor. The microprocessor 22 generates suitable routing instructions for the driver that include both visual data shown on the display 24 and audible data via a speaker 30 (
As shown, in order to enhance the precision of the position determination, the determination system may also include a DMI (Distance Measurement Instrument) 32. This instrument is an odometer that measures a distance traveled by the vehicle 10 by sensing the number of rotations of one or more of the wheels 12. The DMI 32 may operate with a sampling frequency of 10 or more Hz. The DMI 32 is also connected to the microprocessor 22 to allow the microprocessor 22 to take the distance as measured by the DMI 32 into account while processing the output signals from the GPS unit 16. DMIs are not widely applied in in-car navigation systems. And of course embedded navi systems can receive odometer input via the vehicle bus.
In a further embodiment, and to further enhance the precision of the position determination, the position determination system may include an IMU (Inertial Measurement Unit) 34. Such an IMU 34 can, for example, be implemented as three gyro units arranged to measure rotational accelerations and three accelerometers arranged to measure translational accelerations along three orthogonal directions. The IMU 34/gyros and accelerometers may, for example, operate with a sampling frequency of 200 Hz. The IMU 34 is also connected to the microprocessor 22 to allow the microprocessor 22 to take the measurements by the IMU 34 into account while processing the output signals from the GPS unit 16. Like DMIs, IMUs are not widely applied in in-car navigation systems. Presently, more and more IMUs are being installed to cope with GPS outages due to urban canyons, etc. In the future, navigation devices will be expected to allow lane level positioning. For these futuristic applications to be of full potential, it is important to know in which lane the vehicle is driving. Thus, methods will be sought by which the lateral position of a vehicle on the road can be assessed to identify the appropriate lane in which is it or should be traveling. The processor 36 may also be connected to a receiver of broadcasted information or digital communication network (e.g. radio RDS, DAB) or cellular GPRS/EDGE/UMTS network
It will be understood by one skilled in the art that there are other navigational sensors that may be added or substituted to the suite described above to provide a position and heading determination at the performance/cost point desired.
The display 24 may be a so-called head-up display HUD. Examples of HUDs are: fixed HUDs and helmet mounted HUDs. Fixed HUDs may be used in vehicles and require the driver to look through a display element attached to the vehicle chassis. The navigation system 14 determines the image to be presented depending solely on the orientation of the vehicle 10. Helmet mounted displays (HMD) are technically a form of HUD, the distinction being that they feature a display element that moves with the orientation of the user's head.
In
The processor 36 may be connected to a communication network 48 via a wireless connection, for instance, the Public Switched Telephone Network (PSTN), a Local Area Network (LAN), a Wide Area Network (WAN), the Internet etc. by means of I/O means 50. The processor 36 may be arranged to communicate with other communication arrangements through the network 48. The physical data carrier received in the reading unit 46 may comprise a computer program product in the form of data and instructions arranged to provide the processor 36 with the capacity to perform a method in accordance with the invention. However, such computer program product may, alternatively, be downloaded via the telecommunication network 48. The processor 36 may be implemented as a stand alone system, or as a plurality of parallel operating processors each arranged to carry out subtasks of a larger computer program, or as one or more main processors with several sub-processors.
Referring to
Various methods can be employed to deduce the average speed of traffic flowing on the second road segment 54. This may include the use of speed cameras 58, induction loops 60, probe data, or by other techniques and devices. Probe data will typically comprise the real time transmission of position and/or speed data from navigation systems residing in vehicles traveling along the second road segment 54. Speed data can also be collected with telephone probe information, as is used for HDTraffic. Of course, other techniques could be used to deduce or estimate the average speed of traffic traveling the second road segment 54, such as by historical data, extrapolated information acquired from other sensing locations and the like. This information can be averaged for specific time in a day, day in a week, season, considering holiday periods, etc, to achieve good estimates for the real time of driving (known from the GPS clock or any other clock in the navigation device). Therefore, it is possible to use map data in which time dependent speed profile information has been collected and provided. For example, it has been determined that at 8 AM on Monday the average on that merging section is 25 km/h, and on Tuesday at 22 h. it is 110 km/h, etc.
In the example shown in
Referring now to
In the exemplary situation of
A junction view can be presented on the display 24 in which image data corresponding to a real life view of the junction 56 is visible to a user of the navigation system 14 approaching the junction 56. Such junction views can be prerecorded and/or computer generated. Naturally, the merge data and recommendations can be part of a calculated route which leads the vehicle 66 from a starting position to a particular destination. In an appropriately fitted navigation system 14, it is possible to receive sufficiently accurate position data so as to place the vehicle 66 in a particular lane on its road segment. Thus, in combination with a previously established driving route, the navigation system 14 may inform a driver of the vehicle 66 how many lanes to shift leftward or rightward so as to arrive at a desired lane according to the predetermined route along which the driver is encouraged to follow. Looking forward to an embodiment of this invention described subsequently in connection with
It should be noted that in ideal circumstances, the communications and/or recommendations are provided well before the vehicle 66 enters the merging area or junction 56.
Navigation systems 14 according to this invention are shown residing in a first vehicle 68 on the first road segment 52′ and a second vehicle 70 on the second road segment 54′. I.e., vehicles 68 and 70 correspond to vehicle 10 as described earlier. Each navigation system 14 communicates relevant information to its driver regarding the upcoming merger of the first and second road segments 52′, 54′. As relates to the first vehicle 68, the navigation system 14 audibly communicates that “FAST traffic [will be] merging from LEFT in 200 Meters.” Thus, the driver of vehicle 68 is forewarned that traffic flowing along the second road segment 52′ has a greater average speed, that merger will occur from the left, and that the end of the junction 56′ will occur in 200 meters. Furthermore, the driver of the first vehicle 68 is notified that the “Average speed of merging traffic is 95 km/h.” Thus, the driver of the first vehicle 68 will be notified of the average speed of traffic on the second road segment 54′ so that due consideration can be given for the upcoming merger of traffic flows within the junction 56′. Similarly, the navigation system 14 residing in the second vehicle 70 notifies its driver that “SLOW traffic [will be] merging from RIGHT in 200 Meters.” Thus, this driver knows that traffic on the first road segment 52′ is moving slower, that the merge direction will come from the right, and that the end of the upcoming junction 56′ occurs in 200 meters. Furthermore, the driver of the second vehicle 70 is notified that the “Average speed of merging traffic is 75 km/h.” Relative speed change recommendations can also be given at this time, such as “Accelerate” or “Decelerate” through visual and/or audible techniques. The driver of the second vehicle 70 may also be encouraged to “Move to the Left Lane” for the purpose of making more space for the merging traffic. By providing drivers with this information, the stress of merging with the traffic flow in the first road segment 52′ can be reduced and thereby improve the driving experience as well as driving safety of all concerned. Of course, the specific phasing of these instructions can be adapted as needed.
Whether the subject method and navigation system 14 is used within the context of merging traffic flow from an on-ramp, lane mergers, lane reductions, or otherwise, the information communicated to the vehicle driver concerning the average speed of traffic in the other road segment substantially enhances the driver's ability to pilot a vehicle in a safe, courteous manner. The subject method and navigation system 14 contemplates not only real-time speed assessments obtained by sensors, cameras and/or probe data, but also the use of historical speed data which can be stored in a map and used in products that calculate routes based on the real average speed measured on roads rather than speed limits, such as IQ
Routes available from TomTom NV. The navigation system would then use the average merging speed at the upcoming road section to calculate and display a recommended merging speed. So in general the invention could have a real-time component in which information is obtained from the infrastructure or via a service centre, or the invention can be implemented on a less advanced platform.
The navigation system 14 and method then recommends a speed change to the vehicle on the first road segment 52 if its monitored speed does not equal the average speed determined of vehicles traveling on the second road segment 54. This recommendation can be coupled with communicating the average speed of traffic on the second road segment 54, communicating the distance to the end of the junction 56, visually displaying distance and directional information, cues and other graphical data useful for navigation purposes. Thus, the subject navigation system 14, together with its implementation method, provides the driver with a preview of the situation ahead, thereby allowing her or him to focus on the speed necessary to achieve a fluidic merger with traffic even if the upcoming merger zone or end of the junction 56 is not visible. Advantageously, there is no need for precise lane-level positioning and map information in the context of this invention. Thus, in lane merger situations, even if the driver is not in the particular lane that will suddenly end, he or she will be advised if surrounding traffic will suddenly perform lane merger actions so that proactive and defensive/courteous driving maneuvers can be implemented. This situation would thus be applicable to the second vehicle 70 as shown in
In one implementation of this invention, a digital map representation includes a triggering mechanism to initiate the described lane merging warnings and recommendations. For example, the simple road elements attached to nodes can include certain attribute information to trigger the warnings. As an example, road segment represented by the merging section of
Steps can be taken, in a proactive manner, to detect entry points and thereby preprocess images for the database or to generate on-the-fly images presented through the display 24. For example, if the vehicle is soon or currently in a gas station, parking or rest area, or going back to a motorway, these factors can be used to anticipate which images may be needed to display and which voice commands may be required to announce in the very near future. Likewise, if the vehicle is approaching a junction 56, 56′ where lanes are merging or where the number of lanes changes ahead, these preprocessing steps may be useful.
The foregoing invention has been described in accordance with the relevant legal standards, thus the description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiment may become apparent to those skilled in the art and fall within the scope of the invention. For example, the navigation system 14 may be arranged as an in-car navigation system in a vehicle 10. The computer program included within the system may be arranged to allow its processor 36 to perform the action of receiving position data from a position determination device as to a lane in which the vehicle 10 is driving and informing a driver of the vehicle how many lanes to shift leftward or rightward to arrive at a desired lane according to the route to be followed by the driver. The processor 36 may be connected to a memory storing route planning software arranged to calculate a route to be followed from a starting position to a destination or a likely path forward to the vehicle, in case the routing function is not switched on. Accordingly the scope of legal protection afforded this invention can only be determined by studying the following claims.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP09/65033 | 11/12/2009 | WO | 00 | 7/23/2012 |
