Method and apparatus for adjusting distance for generating maneuver instruction for navigation system
A distance adjustment method and apparatus for a navigation system produces a maneuver instruction for an intersection at the most appropriate timing and location during the route guidance. The method includes the steps of: searching an upcoming intersection on the calculated route that requires the user to make a turn therein; retrieving data concerning the upcoming intersection from a map database; adjusting a final distance from a reference point of the intersection by evaluating the retrieved data concerning the intersection; and generating a maneuver instruction at a timing when the user has reached the adjusted final distance from the reference point of the intersection, thereby notifying the user to make a turning maneuver at the intersection.
This invention relates generally to a method and apparatus for generating an instruction for turning at an intersection, and more particularly, to a method and apparatus of distance adjustment to improve accuracy in the timing of announcing or otherwise notifying a turning maneuver to a user by a navigation system with respect to a particular intersection by evaluating various factors involved in the intersection.
BACKGROUND OF THE INVENTIONA navigation system performs travel guidance for enabling a user to easily and quickly reach the selected destination. A typical example is a vehicle navigation system where a vehicle is equipped with a navigation function to guide a driver to a destination through a calculated route. Such a navigation system detects the position of the user's vehicle, and reads out map data pertaining to an area at the current vehicle position from a data storage medium, for example, a CD-ROM (compact disc read-only memory), a DVD (digital versatile disc), a hard disc, or from a remote data server.
By selecting, for example, a “Point of Interest” method in
After determining the route, the navigation system starts the route guidance operation. As shown in
However, a distance to the maneuver point of the intersection may not be appropriate with respect to a timing of announcing the maneuver action depending on circumstances of the intersection. For example, inaccuracy of such distance or timing is caused by a digitization method used in the map data where a maneuver point is defined as a crossing point of center lines. The problem associated with such a conventional method is described with reference to
In the example of
More specifically, as shown in
The conventional technology may work well if an intersection is small as in the case of the intersection 20b shown in
Therefore, there is a need of a new method and apparatus for navigation system to produce the maneuver instruction such as voice announcement at a more appropriate timing. There is need of a new method and apparatus for navigation system to produce the maneuver instruction at an appropriate timing even when the size and structure of the intersection, directions of turn, etc. vary.
SUMMARY OF THE INVENTIONIt is, therefore, an object of the present invention to provide a distance adjustment method and apparatus for a navigation system which is capable of producing a maneuver instruction for an intersection at the most appropriate timing and location.
It is another object of the present invention to provide a distance adjustment method and apparatus for a navigation system which adjusts a distance from the reference point of the intersection to the point where the turn instruction will be made by evaluating various factors including a direction of turn, a structure and size of the intersection, etc.
It is a further object of the present invention to provide a distance adjustment method and apparatus for a navigation system which adjusts a distance from the reference point of the intersection to the point where the turn instruction will be made by evaluating various factors including a number of lanes, a width of a lane, size of a center divider, etc.
One aspect of the present invention is a distance adjustment method for a navigation system for announcing a maneuver instruction at the most appropriate timing. The method includes the steps of: conducting a route guidance operation of the navigation system for guiding a user to a destination through a calculated route; searching an upcoming intersection on the calculated route that requires the user to make a turn therein within a predetermined distance range ahead from a current position; retrieving data concerning the upcoming intersection from a map database; adjusting a final distance from a reference point of the intersection by evaluating the retrieved data concerning the intersection; and generating a maneuver instruction at a timing when the user has reached the adjusted final distance from the reference point of the intersection, thereby notifying the user to make a turning maneuver at the intersection.
In the distance adjustment method of the present invention, the final distance from the reference point of the intersection is adjusted depending on a direction of the turning maneuver at the intersection. Further, the final distance from the reference point of the intersection is adjusted depending on a direction of the turning maneuver at the intersection and a number of lanes involved in the intersection with use of the retrieved data concerning the intersection. Furthermore, in the distance adjustment method of the present invention, the final distance from the reference point of the intersection is adjusted depending on a direction of the turning maneuver at the intersection and a number of lanes involved in the intersection and a width of each lane with use of the retrieved data concerning the intersection.
The distance adjustment method of the present invention further includes a step of retrieving a reference distance from the reference point of the intersection, a step of obtaining an adjusted distance based on a direction of the turning maneuver at the intersection and other relevant information derived from the retrieved data concerning the intersection, and a step of combining the reference distance and the adjusted distance to obtain the final distance.
In the distance adjustment method, the step of obtaining the adjusted distance includes a step of detecting a number of lanes involved in the intersection and a width of each lane from the retrieved data, and a step of multiplying the number of lanes and the width of the lane.
The distance adjustment method of the present invention further includes a step of retrieving a reference distance from the reference point of the intersection, and a step of changing the reference distance based on a direction of the turning maneuver at the intersection and other relevant information derived from the retrieved data concerning the intersection thereby determining the final distance from the reference point.
In distance adjustment method of the present invention, the step of changing the reference distance for determining the final distance includes a step of incorporating a half width of a road segment where one road segment is involved in the intersection, and a step of either adding or subtracting the half width from the reference distance depending on the direction of the turning maneuver.
Further, the step of changing the reference distance for determining the final distance includes a step of incorporating a half width of a road segment where one road segment is involved in the intersection, a step of incorporating a half width of a center divider of the intersection, and a step of either adding or subtracting the half width of the road segment and the center divider from the reference distance depending on the direction of the turning maneuver.
In the distance adjustment method of the present invention, the reference distance is modified by evaluating various factors including a vehicle speed, traffic congestion, and weather condition.
Another aspect of the present invention is a distance adjustment apparatus for a navigation system to generating a maneuver instruction at the most appropriate timing by implementing the various steps of the display method described above. The distance adjustment apparatus of the present invention adjusts a distance from the reference point of the intersection to the point where the turn instruction will be made by evaluating various factors including a direction of turn, a structure and size of the intersection, a number of lanes, a width of a lane, size of a center divider, etc.
According to the present invention, the navigation system is able to produce the maneuver instruction for the intersection at the most appropriate timing. During the route guidance operation, the method and apparatus of the present invention adjusts a distance from the reference point of the intersection to the point where the turn instruction will be made by evaluating the information. Such information includes a type of an intersection, a size of the intersection such as a number of lanes, a shape or size of a center divider if any, and a direction of turn such as right turn or left turn, a speed of a vehicle, weather condition, etc. In one embodiment, in addition to the reference distance “dr” incorporated in the conventional technology, the present invention utilizes the adjusted distance “da” so that the maneuver instruction is produced when the vehicle reaches the final distance “dr +da” from the reference point. In another embodiment, a specific structure concerning a double-digitized road and its associated data such as a center divider are incorporated to determine the adjusted final distance. Thus, the driver is informed to make a turn sufficiently prior to reach the turning point of the intersection but is not too early until reaching the turning point.
The method and apparatus for adjusting a distance between a reference point and an announcement point thereby producing a maneuver instruction at an appropriate timing is explained in detail with reference to the accompanied drawings. The present invention is designed to produce a maneuver instruction, typically, voice announcement of “Make a Right Turn”, “Make a Left Turn”, etc. at an appropriate timing, i.e., not too late and not too early. During the route guidance operation, the method and apparatus of the present invention adjusts a distance from the reference point of the intersection to the point where the turn instruction will be made by evaluating the information on a type of an intersection, a size of the intersection such as a number of lanes, a shape or size of a center divider if any, and a direction of turn such as right turn or left turn, a speed of a vehicle, weather condition, etc.
Thus, the navigation system of the present invention is able to provide the maneuver instruction at an appropriate timing for a driver corresponding to particular conditions of the intersection. Thus, the driver is informed to make a turn sufficiently prior to reach the turning point of the intersection but is not too early until reaching the turning point. The navigation system achieves this effect by adjusting the timing or distance from the reference point for announcing the maneuver instruction by evaluating the various factors obtained from the existing and future map database incorporated in the navigation system.
It should be noted that the present invention is described herein mainly for the case where the display method and apparatus is applied to a vehicle navigation system for an illustration purpose. However, the method and apparatus under the present invention can be implemented to other devices with the navigation function, such as cellular phones, portable data terminals, laptop computers, or personal computers.
In the example of
In the example of
In the present invention, the adjusted distance “da” is added to the reference distance “dr” so that the maneuver instruction such as “Make a Right Turn” is generated at a location A which is a final distance (sum of distances da+dr) away from the reference point 21. The location A will be, for example, about 30 feet away from the corner point 23 which is a point for the right turn. As a consequent, the navigation system allows the user to be well prepared for the maneuver and to make a right turn safely and comfortably at the corner point 23.
The information on the number of lanes can be obtained from the map database which is stored in a storage medium such as DVD, HD (hard disc), etc. of the navigation system. The information on the number of lanes may not be sufficiently provided in the today's map database but will be fully provided in the map database of near future. A width of each lane is given in the map database, or known by a person of ordinary skill in the art, or can be estimated relatively accurately according to the information such as functional classes of the road segments.
In this example, a size of a cross street is determined by a number of lanes and a width of each lane, for example, 10 feet. Thus, in the case where the number of lanes is 3, and the width of each lane is 10 feet, the total distance (width) of the cross street at one side is calculated by 3 multiplied by 10 feet, which results in 30 feet. Thus, in determining the overall distance to a maneuvering point, the reference distance “dr” is offset by the adjusted distance “da” which is 30 feet in this case.
The lane width may not be limited to a particular value but may vary between street to street. For example, the lane width may be different according to the type of the street or functional class, such as a residential street, a main street or a street in an industrial area, etc. Thus, for adjustment of the distance in the present invention, for a larger street, a wider width is assigned while a narrower width is assigned to a smaller street.
Thus, in the example of
As noted above, the process of
The step 101 will be repeated until an intersection will be found, and if it is determined that there is an intersection, the navigation system detects a reference point of the intersection in the step 102. Typically, the reference point is a center point of the intersection such as the point 21 in
As noted above, in the example of
As noted above, information concerning a lane number may not be complete in the currently marketed map database but will be fully available in the near future. If the lane number information is not available from the map database, the procedure will simply proceed to the next step. During this process, if lane number information is unavailable, the navigation system may assume the lane number based on the type and road class of the cross street.
In the next step 104, the navigation system will check whether other relevant information is available from the map database. The information relevant to the distance adjustment of the present invention may include a structure of cross street (whether there is a center divider, a width of each lane, etc.), a functional (road) class of street (major street, residential street, etc.), a current speed of the vehicle, a direction of turn at the intersection, etc. After obtaining all the relevant information in the steps 103 and 104, the navigation system performs a calculation operation in the step 105.
In the calculation operation in the step 105, the navigation system incorporates the lane number and the lane width to determine an overall distance from the reference point to the entrance point of the intersection. As will be described later, if the intersection (cross street) includes a center divider, the size and shape of such a center divider will be incorporated in the calculation. Through the calculation operation, the navigation system determines the adjusted distance “da” described above with reference to
Based on the calculation operation in the step 105, the navigation system determines the timing of announcing the maneuver instruction in the step 106. In the example of
In the example of
Thus, in the intersection 20c of
A road width L1 represents the width of the road segment 70A, a road width L2 represents the width of the road segment 70B, and L3 represents a width of the center divider 71. The existing map database includes, at least in a certain level, the information regarding the road width L1 and L2 of the road segments and the width L3 of the center divider so that the navigation system is able to retrieve them. A map database in the near future will incorporate such information in a more complete fashion.
In
Namely, with use of the reference point 21 and the reference distance “dr”, the final distance D1 is calculated as follows:
D1=dr−(L1/2+L3/2)
where L1 is a road width of the road segment 70A and L3 is a width of the center divider 71. It is apparent that if there are two road segments 70A on one side, L1/2 will be modified to L1(1+1/2) and so on. Accordingly, the navigation system generates the maneuver instruction such as “Make a Left Turn” at the distance D1 away from the reference point 21, which is an appropriate timing, i.e, not too late and not too early.
In
Namely, with use of the reference point 21 and the reference distance “dr”, the final distance D2 is calculated as follows:
D2=dr+(L2/2+L3/2)
where L2 is a lane width of the road segment 70B and L3 is the width of the center divider 71. It is apparent that if there are two road segments 70B on one side, L2/2 will be modified to L2(1+1/2) and so on. Accordingly, the navigation system generates the maneuver instruction such as “Make a Right Turn” at the distance D2 away from the reference point 21, which is an appropriate timing, i.e, not too late and not too early.
In the present invention, it is preferable to also modify the reference distance “dr” dynamically by taking the speed of the vehicle, type of the street being driven on, traffic congestion, weather condition, etc., into consideration. For instance, the reference distance “dr” may be modified such that the higher the speed of the vehicle, the longer the reference distance becomes. Further, the reference distance “dr” may be modified such that if the weather condition is not good (ex. raining), the reference distance becomes longer.
Such determination is made for a predetermined distance range of the calculated route to the destination ahead of the current vehicle position. The step 110 will be repeated until an intersection that needs to make a turning maneuver will be found on the calculated route. If it is determined that there is an intersection, the navigation system detects a reference point of the intersection and the predetermined reference distance “dr” in the step 111.
Typically, the reference point is a center point of the intersection as shown in
In the case of left turn, the navigation system detects a width L1 of the road segment 70A in the step 113. The navigation system also detects a width L3 of the center divider 71 in the step 114. In the step 115, the navigation system applies the formula “D1=dr−(L1/2+L3/2)” to obtain the distance D1 with use of the reference point 21 and the reference distance “dr”, where L1 is the road width of the road segment 70A and L3 is a width of the center divider 71. Based on the calculation, in the step 116, the navigation system produces the maneuver instruction by voice announcement and/or displaying a mark, icon, etc., for the left turn, when the vehicle reaches the distance Dl from the reference point 21.
In the case of right turn, the navigation system detects a width L2 of the road segment 70B in the step 117. The navigation system also detects a width L3 of the center divider 71 in the step 118. In the step 119, the navigation system applies the formula “D1=dr+(L1/2+L3/2)” to obtain the distance D2 with use of the reference point 21 and the reference distance “dr”, where L2 is the road width of the road segment 70B and L3 is a width of the center divider 71. Based on the calculation, in the step 120, the navigation system produces the maneuver instruction by voice announcement and/or displaying a mark, icon, etc., for the right turn, when the vehicle reaches the distance D2 from the reference point 21.
The block diagram of
In
When the navigation system is in the route guidance mode to guide the user to the destination through the calculated route, the CPU 139 determines whether there is an intersection that requires the user to make a turn on the calculated route to reach the destination. If there is an intersection to make a turn, the CPU 139 detects the reference point of the intersection and the reference distance “dr”. The CPU 139 also detects the information concerning the intersection such as a direction of turn, a number lanes involved, a width of the lane, a number of lanes, a particular structure of the intersection, a functional class of cross street, etc. After obtaining all the relevant information, the CPU 139 performs a calculation operation and determines the adjusted distance described above with reference to
In the block diagram of
The block diagram of
In
The CPU 139 controls an overall operation of the navigation system including the distance adjustment operation under the present invention as described above for producing a maneuver instruction at an appropriate timing. The data related to the distance adjustment will be stored in the buffer memory 148 for further processing. A program that performs the procedure of the present invention including the one shown in the flow charts of
As has been described above, according to the present invention, the navigation system is able to produce the maneuver instruction for the intersection at the most appropriate timing. During the route guidance operation, the method and apparatus of the present invention adjusts a distance from the reference point of the intersection to the point where the turn instruction will be made by evaluating the information. Such information includes a type of an intersection, a size of the intersection such as a number of lanes, a shape or size of a center divider if any, and a direction of turn such as right turn or left turn, a speed of a vehicle, weather condition, etc. In one embodiment, in addition to the reference distance “dr” incorporated in the conventional technology, the present invention utilizes the adjusted distance “da” so that the maneuver instruction is produced when the vehicle reaches the distance “dr+da” from the reference point. In another embodiment, a specific structure concerning a double-digitized road and its associated data such as a center divider are incorporated to determine the adjusted distance. Thus, the driver is informed to make a turn sufficiently prior to reach the turning point of the intersection but is not too early until reaching the turning point.
Although the invention is described herein with reference to the preferred embodiment, one skilled in the art will readily appreciate that various modifications and variations may be made without departing from the spirit and scope of the present invention. Such modifications and variations are considered to be within the purview and scope of the appended claims and their equivalents.
Claims
1. A distance adjustment method for a navigation system, comprising the following steps of:
- conducting a route guidance operation of the navigation system for guiding a user to a destination through a calculated route;
- searching an upcoming intersection on the calculated route that requires the user to make a turn therein within a predetermined distance range ahead from a current position;
- retrieving data concerning the upcoming intersection from a map database;
- adjusting a final distance from a reference point of the intersection by evaluating the retrieved data concerning the intersection; and
- generating a maneuver instruction at a timing when the user has reached the adjusted final distance from the reference point of the intersection, thereby notifying the user to make a turning maneuver at the intersection.
2. A distance adjustment method for a navigation system as defined in claim 1, wherein the final distance from the reference point of the intersection is adjusted depending on a direction of the turning maneuver at the intersection.
3. A distance adjustment method for a navigation system as defined in claim 1, wherein the final distance from the reference point of the intersection is adjusted depending on a direction of the turning maneuver at the intersection and a number of lanes involved in the intersection with use of the retrieved data concerning the intersection.
4. A distance adjustment method for a navigation system as defined in claim 1, wherein the final distance from the reference point of the intersection is adjusted depending on a direction of the turning maneuver at the intersection and a number of lanes involved in the intersection and a width of each lane with use of the retrieved data concerning the intersection.
5. A distance adjustment method for a navigation system as defined in claim 1, further comprising a step of retrieving a reference distance from the reference point of the intersection, a step of obtaining an adjusted distance based on a direction of the turning maneuver at the intersection and other relevant information derived from the retrieved data concerning the intersection, and a step of combining the reference distance and the adjusted distance to obtain the final distance.
6. A distance adjustment method for a navigation system as defined in claim 5, wherein said step of obtaining the adjusted distance includes a step of detecting a number of lanes involved in the intersection and a width of each lane from the retrieved data, and a step of multiplying the number of lanes and the width of the lane.
7. A distance adjustment method for a navigation system as defined in claim 1, further comprising a step of retrieving a reference distance from the reference point of the intersection, and a step of changing the reference distance based on a direction of the turning maneuver at the intersection and other relevant information derived from the retrieved data concerning the intersection thereby determining the final distance from the reference point.
8. A distance adjustment method for a navigation system as defined in claim 7, wherein said step of changing the reference distance for determining the final distance includes a step of incorporating a half width of a road segment where one road segment is involved in the intersection, and a step of either adding or subtracting the half width from the reference distance depending on the direction of the turning maneuver.
9. A distance adjustment method for a navigation system as defined in claim 7, wherein said step of changing the reference distance for determining the final distance includes a step of incorporating a half width of a road segment where one road segment is involved in the intersection, a step of incorporating a half width of a center divider of the intersection, and a step of either adding or subtracting the half width of the road segment and the center divider from the reference distance depending on the direction of the turning maneuver.
10. A distance adjustment method for a navigation system as defined in claim 5, wherein the reference distance is modified by evaluating various factors including a vehicle speed, traffic congestion, and weather condition.
11. A distance adjustment apparatus for a navigation system, comprising:
- means for conducting a route guidance operation of the navigation system for guiding a user to a destination through a calculated route;
- means for searching an upcoming intersection on the calculated route that requires the user to make a turn therein within a predetermined distance range ahead from a current position;
- means for retrieving data concerning the upcoming intersection from a map database;
- means for adjusting a final distance from a reference point of the intersection by evaluating the retrieved data concerning the intersection; and
- means for generating a maneuver instruction at a timing when the user has reached the adjusted final distance from the reference point of the intersection, thereby notifying the user to make a turning maneuver at the intersection.
12. A distance adjustment apparatus for a navigation system as defined in claim 11, wherein the final distance from the reference point of the intersection is adjusted depending on a direction of the turning maneuver at the intersection.
13. A distance adjustment apparatus for a navigation system as defined in claim 11, wherein the final distance from the reference point of the intersection is adjusted depending on a direction of the turning maneuver at the intersection and a number of lanes involved in the intersection with use of the retrieved data concerning the intersection.
14. A distance adjustment apparatus for a navigation system as defined in claim 11, wherein the final distance from the reference point of the intersection is adjusted depending on a direction of the turning maneuver at the intersection and a number of lanes involved in the intersection and a width of each lane with use of the retrieved data concerning the intersection.
15. A distance adjustment apparatus for a navigation system as defined in claim 11, further comprising means for retrieving a reference distance from the reference point of the intersection, means for obtaining an adjusted distance based on a direction of the turning maneuver at the intersection and other relevant information derived from the retrieved data concerning the intersection, and means for combining the reference distance and the adjusted distance to obtain the final distance.
16. A distance adjustment apparatus for a navigation system as defined in claim 15, wherein said means for obtaining the adjusted distance includes means for detecting a number of lanes involved in the intersection and a width of each lane from the retrieved data, and means for multiplying the number of lanes and the width of the lane.
17. A distance adjustment apparatus for a navigation system as defined in claim 11, further comprising means for retrieving a reference distance from the reference point of the intersection, and means for changing the reference distance based on a direction of the turning maneuver at the intersection and other relevant information derived from the retrieved data concerning the intersection thereby determining the final distance from the reference point.
18. A distance adjustment apparatus for a navigation system as defined in claim 17, wherein said means for changing the reference distance for determining the final distance includes means for incorporating a half width of a road segment where one road segment is involved in the intersection, and means for either adding or subtracting the half width from the reference distance depending on the direction of the turning maneuver.
19. A distance adjustment apparatus for a navigation system as defined in claim 17, wherein said means of changing the reference distance for determining the final distance includes a step of incorporating a half width of a road segment where one road segment is involved in the intersection, means for incorporating a half width of a center divider of the intersection, and means for either adding or subtracting the half width of the road segment and the center divider from the reference distance depending on the direction of the turning maneuver.
20. A distance adjustment apparatus for a navigation system as defined in claim 15, wherein the reference distance is modified by evaluating various factors including a vehicle speed, traffic congestion, and weather condition.
Type: Application
Filed: Feb 26, 2008
Publication Date: Aug 27, 2009
Inventors: Tien Vu (Torrance, CA), Clayton Napohaku (Torrance, CA)
Application Number: 12/072,408
International Classification: G01C 21/36 (20060101);