Data processing: vehicles – navigation – and relative location – Navigation – Employing position determining equipment
Reexamination Certificate
2000-06-29
2001-11-20
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Navigation
Employing position determining equipment
C340S990000, C340S991000, C340S988000, C455S059000, C342S457000, C343S823000
Reexamination Certificate
active
06321162
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for taking into account supplementary traffic information for operating an onboard travel control system of a motor vehicle, including an internal digital road map, by transferring a point of origin and destination to a central computer and transmitting, to the onboard travel control system of the motor vehicle, a route plan drawn up in the central computer, taking into account the supplementary traffic information.
BACKGROUND OF THE INVENTION
Conventional onboard travel control systems have been in use for a number of years, at least in high-end vehicles. The travel control systems include a navigation system to enable the vehicle's present position to be determined. For this purpose, satellite navigation is generally combined with an evaluation by vehicle sensors. Travel control systems further include at least one digital road map that is part of the travel control system, for example in the form of a CD-ROM. The onboard travel control systems operate autonomously, but are not able to take into account up-to-date traffic information.
A method for transmitting traffic information in a standardized protocol is known from Preliminary European Standard ENV12313-1. This method uses location codes that can be used to identify all of a country's traffic-related nodes that are listed in a location table. In addition to location coding, the protocol also codes the direction and extent of the route, thereby making it possible to define the territory described by the traffic disturbance. The traffic information is transmitted in the radio data system (RDS) along with a radio broadcast and can be stored, decoded, and output in a suitable form as a traffic message channel (TMC) in the receiver. To enable the travel control system to take the traffic information into account, the digital maps used in the travel control system are provided with the information in the location table, thereby determining whether an up-to-date item of traffic information affects the pre-calculated route in the case in hand. The onboard travel control system is able to automatically use the traffic information only to a limited extent, due to the considerable cost that this involves. The system does not take into account traffic forecasts and can take into account only events limited to the TMC locations for route planning purposes.
Attempts have therefore been made to use a central computer for performing a route calculation that takes into account the up-to-date traffic information and to supply the route calculation as a service, for examples in a mobile radio system. For this purpose, the onboard travel control system must be provided with a remote data transmission system. To interpret the centrally calculated, optimized route in the vehicle itself, the central office must use an easy-to-understand digital map. According to a method of this type used by Mercedes Benz in Tokyo, the route is transmitted by arranging the route components to be traveled in sequential order. The identifiers for the route components are then transmitted in a code that can be used only in Tokyo. This has a particular disadvantage in that, with complex routes, the transmission capacity required increases in more or less linear proportion to the length of the route. The transmission capacity requires the use of expensive point-to-point data connections, with the transmission of a route for a trip within the city of Tokyo requiring transmission times of at least 45 seconds. Data transmissions of such a duration cannot be reliably ensured while driving a vehicle.
SUMMARY OF THE INVENTION
An object of the present invention is to simplify the transmission of a centrally calculated route plan to an onboard travel control system and to carry out this transmission within a shorter period of time.
To achieve the object, a method is provided. in that, according to the present invention in which, the internal digital road map of the travel control system is provided with information about location codes; the route plan is transmitted by specifying route segments that are defined by the location codes and lie between the point of origin and destination; and the transmitted route segments are modified in the internal digital road map of the travel control system so that they are taken into account as a higher priority than other non-transmitted route segments during the subsequent route selection carried out in the onboard travel control system.
According to the present invention, the optimized route determined in the central computer is transmitted by transmitting route segments that are loaded to the onboard travel control system in a location-encoded format. To do this, the onboard travel control system has information about the location codes used by providing the internal digital road map in advance with information about the location codes used. The transmitted route segments are used to modify the internal digital road map-possibly after converting the transmitted location codes to the location codes used in the internal digital map via tables or algorithms-by using them as high-priority route segments for operating the onboard travel control system. The high priority can be identified, for example, by assigning a very high valid average speed. The transmitted route segments can follow each other seamlessly, although this is not necessary clearly define the overall route. Any gaps between the route segments are filled in by the onboard travel control system. Likewise, the onboard travel control system determines the path from the point of origin to the entry point at the first route segment to be traveled and output the correct directions. A similar procedure applies when leaving the last selected route segment to reach the specific destination. Consequently, the onboard travel control system fills in any gaps between the transmitted route segments and performs a separate navigation operation, independently of the central computer, at the point of origin and for the destination if the point of origin and/or the destination do not happen to match a location contained in the location table. In addition to the advantage that the optimum, calculated route does not have to be transmitted in its entirety for the method according to the present invention to work, there is also the advantage that only the street segments for which traffic information is available in tables (such as the TMC location table) need to be defined and synchronized between the central office and the onboard travel control system.
Upon receipt of TMC-encoded traffic disturbances, the stored, preferred route can be checked. If a traffic disturbance is located in a preferred route segment, the modification of the route segment affected can be altered to cancel its priority and take the traffic disturbance into account. The priority can be canceled locally, if necessary, without losing the rest of the preferred route in the onboard travel control system, eliminating the need to recalculate the route in the central office at additional expense.
In one preferred embodiment of the method according to the present invention, the route segment codes are composed of a code for a specific position on a specific street, a code for the direction on the street, and a code for the extent of the route segment on the street. This code structure matches the location code provided for the traffic information encoded for RDS transmission. However, it is also possible to encode a route segment according to a different structure, for example, by specifying a street and the geographical coordinates for the entry point and exit point of a transmitted route segment.
Because of the much smaller data volume afforded by the method according to the present invention, the route segments determined by the central computer can be economically transmitted in a system for sending short messages, e.g., in the form of SMS (short message system) signals. This eliminates the need to set up expensive point-to-point connections. Whe
Cuchlinski Jr. William A.
Kenyon & Kenyon
Robert & Bosch GmbH
To Tuan C
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