CN101290230B

CN101290230B - Road crossing navigation method and navigation system using the navigation method

Info

Publication number: CN101290230B
Application number: CN2008100667217A
Authority: CN
Inventors: 张文星
Original assignee: Shenzhen Careland Technology Co Ltd
Current assignee: Shenzhen Careland Computer System Technology Co Ltd
Priority date: 2008-04-14
Filing date: 2008-04-14
Publication date: 2011-03-30
Anticipated expiration: 2028-04-14
Also published as: CN101290230A

Abstract

The present invention discloses a navigation method for a way crossing and a navigation system using the same. The navigation method comprises the following steps of: detecting the road state navigation information of the next way crossing to obtain a road state parameter; obtaining the road state navigation information of the next way crossing according to a calculation process and finding out a corresponding abstract picture in an abstract picture database to be used as a prompt picture of the way crossing to display. Since the abstract picture database in which various abstract pictures reflecting the navigation information of the road sate of the way crossing are saved is arranged in the navigation system, when the navigation system enters into the way crossing abstract picture mode to navigate, the actual road state navigation information of the way crossing is detected, and then the abstract picture is found out for the navigation. Since most way crossings have the same road state, the navigation system can intuitively display the road condition of the next way crossing, and can not occupy large storage space.

Description

Navigation method for intersection and navigation system using navigation method

Technical Field

The invention relates to the technical field of GPS navigation, in particular to a navigation method for an intersection and a navigation system using the navigation method.

Background

At present, the navigation of the GPS-navigation in a road system is one of the important application directions of the GPS navigation. The GPS antenna of the GPS navigation system receives data information transmitted from at least 3 of 24 GPS satellites that surround the earth, and determines the accurate position of the navigation object in the electronic map by matching the position coordinates determined by the GPS satellite signals with the electronic map stored in the navigation terminal.

When a complex intersection is encountered, particularly when a road is elevated or sinks, the voice prompt is long, and the driving direction in front of the complex intersection is difficult to accurately express, so that a driver is often misled to enter the wrong road, and the navigation system needs other auxiliary ways to guide the user to smoothly pass through the complex intersection. In the prior art, a method of displaying an enlarged intersection map of an intersection and marking an indication graph on an entering road corresponding to the enlarged intersection map is generally adopted to intuitively inform a driver of a driving direction. However, the enlarged map is not enough for the expression of more complicated intersections, especially for some roads with elevation changes, such as high altitude and sinking altitude, the map is difficult to visually reflect the general view of the complicated intersections, a driver carefully observes the behaviors of the map and the dangers of the map in the driving process, and a lot of time is delayed once the road is missed.

In order to better display the actual road condition of the intersection where the driver is currently located, the company filed patent application on 03/14/2008: a method for displaying real scene pictures drawn or shot on the road in one-to-one correspondence at an intersection when the road reaches the intersection is provided in a road display method, a road display device and a navigation device (patent application number: 200810065576.0) which support pictures, so that the road condition of the next intersection can be displayed visually and more humanizedly, and a method for marking an indication graph on a driving road corresponding to the real scene pictures can visually inform the driving direction of a driver. If the condition of entering the branch intersection navigation mode is met, the current branch intersection is obtained through GPS data information and electronic map information, and a live-action picture corresponding to the current branch intersection and an indication graph for guiding the direction, which are pre-stored in a database, are directly obtained from electronic data; and drawing and displaying the live-action picture and the indication graph on a screen.

Fig. 1 shows the structural components of a conventional navigation system:

the navigation system comprises: the portable terminal includes a speaker 1, a storage device 2, an input device 3, an audio output device 4, a display device 5, a control device 6 for controlling the storage device 2, the input device 3, and the audio output device 4, respectively, and a GPS receiving device 16 connected to the control device 6.

The control device 6 is a microcomputer, and can adopt a palm computer, a smart phone, a vehicle-mounted terminal and the like. It includes: a user interface control module 7, a map data management module 8 and a navigation module 9; the navigation module 9 mainly comprises a navigation control module 10, a map display module 11, a route guidance module 12, a route search module 13, an information point retrieval module 14 and a vehicle position detection module 15.

The storage device 2 stores therein map data, control program data, and a live-action picture database reflecting the real-action situation of the intersection, and the storage device 2 restores the recorded contents to digital data and sends the digital data to the control device 6. The storage device 2 is also provided with a corresponding relation table of intersections and live-action pictures, each live-action picture stored in the live-action picture database is in one-to-one correspondence with all intersections in the map data, and the corresponding live-action picture can be inquired according to the intersections in the map data.

In general, the storage device 2 may employ a cartridge device, i.e., an externally inserted memory card or data disk, or the like. The recording medium may be, for example, an SD Card (Secure Digital Card), a TF Card (Trans Flash Card), a CF Card (Compact Flash Card), a DVD (Digital Versatile disc), or the like.

The input device 3 may use a key, a joystick, a knob, a touch panel, or the like. The input device 3 is used for inputting various requirements of a user, and sends input signals of the user to a user interface control module 7 of the control device 6.

The audio output device 4 converts the audio data sent from the control device 6 into an audio signal, and sends the audio signal to the speaker 1. The speaker 1 converts the sound signal sent from the sound output device 4 into sound and outputs the sound, so that the speaker 1 can emit various operation notifications and route guidance voices according to the needs of the control device 6.

The display device 5 may use a lcd (liquid Crystal display) lcd, a projector, or a crt (cathode Ray tube) display, and displays a corresponding image according to the display data sent from the control device 6. For example, the display device 5 may display a map, a self-vehicle location marker, a planned route, a user input interface, and the like.

The GPS receiving device 16 receives signals from GPS satellites, detects the current position and the moving direction of the vehicle, and converts the detected results into protocol data, which is further sent to the own vehicle position detecting module 15 in the navigation module 9 of the control device 6.

The user interface control module 7 of the control device 6 receives the input from the input device 3, generates a control command corresponding to the content required for the input, and sends the control command to one or more sub-modules in the navigation module 9. In addition, the user interface control module 7 responds to the control command and sends the processing result returned from the navigation module 9 to the sound output device 4 and the display device 5.

The map data management module 8 of the control device 6 reads map data including live-action pictures and data contents of guidance-use guidance directions drawn on the live-action pictures from the storage device 2 in response to a request from the navigation module 9.

The navigation control module 10 of the navigation module 9 controls and invokes the remaining sub-modules of the navigation module 9.

The map display module 11 of the navigation module 9 generates display data for map display based on the map data information read from the map data management module 8, and sends the display data to the user interface control module 7.

The route guidance module 12 of the navigation module 9 obtains the map data from the map data processing module 8, performs route guidance processing on the map data, and returns the result of the guidance processing to the map data management module 11, so that the map data management module 11 can perform prediction reading. In addition, the data of the interface, the navigation voice and the like during induction are transmitted to the user interface control module 7.

The route search module 13 of the navigation module 9 acquires the map data from the map data management module 8, performs route search processing on the map data, and returns a route recommended by the route search result system to the route guidance module 12.

The information point search module 14 of the navigation module 9 acquires data to be filtered from the map data management module 8, searches for an information point search command input by the input device 3, and returns the search result to the map data management module 8, the map display module 11, and the route guidance module 12.

The vehicle position detection module 15 of the navigation module 9 transmits data indicating the current position obtained from the GPS receiver 16 to the map data management module 8, the map display module 11, and the route guidance module 12.

The navigation module 9 obtains current position information of the vehicle, when it is detected that the vehicle is about to arrive at the intersection, the real-scene pictures corresponding to the next intersection one by one are obtained by searching from the real-scene picture database, and simultaneously, navigation instruction information, such as pointing arrows, is drawn on the real-scene pictures according to the navigation information and sent to the display device for displaying.

The method for navigating the real-scene pictures at the intersections by the navigation system needs to store the real-scene pictures corresponding to the observation angles of each intersection from each intersection in the navigation system in advance. Because the intersections are numerous, for example, there are thousands of different intersections in Shenzhen city, and one province intersection can reach millions, the navigation system can meet the requirement of navigating by using live-action pictures only by needing a large storage space, and the storage space is greatly occupied. In addition, in this mode, the navigation system developer needs to spend huge capital and a large amount of time to make the live-action pictures of thousands of intersections, which wastes manpower resources greatly, and when the map of the navigation system is changed into a map of other provinces, the live-action picture database for navigating the intersection must be replaced, so that the compatibility and transportability are poor.

Disclosure of Invention

In order to overcome the defects, the invention aims to provide the intersection navigation method which can intuitively display the road condition of the next intersection and does not occupy too much storage space and the navigation system using the intersection navigation method.

The purpose of the invention is realized by the following technical scheme:

a navigation method of an intersection is characterized by comprising a calculation process and a display process,

the calculation process comprises the following steps:

a: the route guiding module detects whether a navigation calculation point of a next intersection is reached; if yes, turning to the step B; if not, continuing to execute the step A;

b: the method comprises the steps that a path guiding module detects road form navigation information of a next intersection to obtain road form parameters, wherein the road form navigation information comprises direction type values and elevation type values of all non-driving road intersections;

the display process comprises the following steps:

c: the route guiding module detects whether a navigation display point of a next intersection is reached; if yes, turning to step D; if not, continuing to execute the step C;

d: and the path guiding module searches an abstract picture corresponding to the direction type value and the elevation type value obtained in the calculation process in an abstract picture database as an intersection prompting picture according to the combination of the direction type value and the elevation type value, and displays the intersection prompting picture on a display device.

In the step B, the step of detecting the road form navigation information of the next intersection includes:

b1: detecting included angle information between all non-driving road intersections and driving road intersections in the next intersection;

b2: searching to obtain a direction type value according to the corresponding relation between the preset angle interval in which the included angle information falls and the direction type value;

in the step D, an abstract picture matched with the direction type value is searched in the abstract picture database according to the direction type value obtained in the step B2 to be used as an intersection prompt picture.

In the step B1, an included angle formed by a connection line between the angle calculation recording point of all non-driving road intersections and the intersection center point and a connection line between the angle calculation recording point of the driving road intersections and the intersection center point is used as included angle information. The design is that if the road is a curved road at the intersection close to the intersection, when people visually observe the angle between the curved road and the intersection of the driving road, a distance is usually extended into the curved road to be used as a visual observation reference point; when the included angle information between roads is calculated, the calculation recording points of the intersections of the roads are arranged at positions away from the central point of the intersection by a certain distance, the obtained result is more in line with the visual measurement result of people, and the navigation effect is better. The first preset distance is 50 meters; and when the total length of the road is less than 50 meters, taking the position of the road farthest from the center point of the intersection as an angle calculation recording point.

And B, arranging elevation calculation recording points at second preset distances from all non-driving road intersections to the intersection central point, wherein the step B of detecting the road form navigation information of the next intersection further comprises the following steps:

b3: detecting and calculating the difference value between the elevation of each non-driving road intersection in the next intersection and the elevation of the intersection center point to obtain elevation difference value information;

b4: searching to obtain an elevation type value according to the corresponding relation between a preset elevation difference range in which the elevation difference information falls and the elevation type value;

in the step D, finding the abstract picture matched with the elevation type value in the abstract picture database according to the elevation type value obtained in the step B4 as the intersection prompt picture. The second preset distance is 50 meters; and when the total length of the road is less than 50 meters, taking the position of the road farthest from the center point of the intersection as an angle calculation recording point.

In the step B, after the step B4, the method further includes:

step B5: the code generation module searches a road code table according to the direction type value and the elevation type value obtained in the step to obtain corresponding codes of roads at each non-driving road intersection; according to the corresponding codes of all roads which do not enter the road intersection, synthesizing picture codes in sequence;

in the step D, the picture calling module searches an abstract picture corresponding to the picture code according to the picture code obtained in the step B5 to be used as an intersection prompting picture.

A navigation system using the above navigation method, comprising:

the self-parking position detection module is used for receiving GPS positioning information and detecting self-parking position information;

the map data module is used for storing map data;

display means for displaying navigation information;

the route guidance module is used for calculating navigation information according to the self-vehicle position information obtained by the self-vehicle position detection module and the map data stored in the middle of the map data module, and sending the navigation information to the display device;

it is characterized in that the preparation method is characterized in that,

the navigation information comprises direction type values and elevation type values of all non-driving road intersections,

the map data module further comprises an abstract picture database, wherein different abstract pictures reflecting the combination of the direction type value and the elevation type value are stored in the abstract picture database.

The road form comprises the number of road intersections of the intersection and the information of included angles between each non-driving road intersection and the driving road intersection;

the path guide module comprises:

the direction calculation module is connected with the map data module and used for calculating included angle information between all non-driving road intersections and driving road intersections in the intersections and obtaining the direction type value of each non-driving road intersection according to the corresponding relation of the included angle information falling into a preset angle interval and the direction type value;

in the abstract picture database, each combination of direction type values of all non-driving road intersections respectively has an abstract picture with the same road form navigation information corresponding to the abstract picture.

The direction calculation module calculates a connecting line between the angle calculation recording point of the non-driving road intersection and the central point of the intersection by inquiring longitude and latitude information of the angle calculation recording point in the map data module, and calculates an included angle formed by the connecting line between the angle calculation recording point of the non-driving road intersection and the central point of the intersection with the angle of the driving road intersection as included angle information between the non-driving road intersection and the driving road intersection.

The distribution condition of the preset angle interval is as follows: the first interval is (0-90 degree), (the second interval is (90-175 degree), (the third interval is (175-185 degree), (the fourth interval is (185-270 degree), and the fifth interval is (270-360 degree)).

The road form navigation information also comprises elevation change information of each road at the intersection; all non-driving road intersections of the intersection are provided with elevation calculation recording points at a second preset distance from the intersection central point,

the path guiding module further comprises:

the elevation calculation module is connected with the map data module, calculates the difference value between the elevation of each non-driving road intersection elevation calculation recording point in the next intersection and the elevation of the intersection center point by inquiring the elevation information of the elevation calculation recording point in the map data module, and obtains the elevation type value of each non-driving road intersection according to the corresponding relation between the preset elevation difference range in which the elevation difference information falls and the elevation type value;

in the abstract picture database, each combination of the direction type value and the elevation type value of all the non-driving road intersections respectively has an abstract picture with the same road form navigation information corresponding to the abstract picture. The elevation information of the detected intersection is added, so that the intersection can be more attached to the actual form of the intersection when the intersection indication picture is displayed, and the user can navigate more intuitively.

The preset corresponding relation between the elevation difference range and the elevation type value is as follows: when the elevation difference value is greater than or equal to-2 m and less than or equal to 2m, the elevation type value is expressed as a horizontal road surface; when the elevation difference value is larger than 2m, the elevation type value is expressed as an ascending road surface; and when the elevation difference value is less than-2 m, the elevation type value is expressed as a sinking road surface.

The path guiding module further comprises:

the code generation module is used for synthesizing the direction type value and the elevation type value of each non-driving road intersection in the intersection into a picture code according to a preset scheme;

and the picture calling module is used for searching a corresponding abstract picture in the abstract picture database according to the picture code generated by the code generating module, and sending the abstract picture as an intersection prompting picture to the display device.

The map data module also comprises an indication graph database which stores a turning indication graph, and the path guiding module is also provided with an indication graph drawing module which is used for drawing the turning indication graph in the indication graph database on the abstract picture. The abstract pictures are selected according to the road form of the intersection, and then the steering indication graph is drawn on the abstract pictures, so that the number of the abstract pictures needing to be stored in the abstract picture database is reduced.

The abstract picture is a view observed from a driving-in angle or a view observed from a preset offset angle. The view observed from the driving angle can better fit the actual navigation situation of the user, and when the road shape of the whole intersection can be better reflected from other angles, the abstract picture can be the view observed from the preset offset angle.

The abstract pictures in the abstract picture database are abstract pictures of a three-way intersection and a four-way intersection; the map data module also comprises a live-action picture database for storing live-action pictures of intersections with more than five branches. The design is that the road shapes of the intersections above five branches are too many, and the number of abstract pictures formed by abstraction is not greatly different from the number of real-scene pictures, so that the intersections above five branches can be represented by concrete real-scene pictures as the intersection prompting pictures.

Because the invention sets the abstract picture database which stores different abstract pictures reflecting the road shape navigation information of the intersection in the navigation system, when the navigation system enters the intersection abstract picture mode to navigate the intersection, can detect the road form navigation information of the actual intersection, find the abstract picture corresponding to the actual intersection as the intersection prompt picture for navigation, because most of the intersections have the same road form in the actual situation, the intersections with the same road form can be navigated by taking the same abstract picture as the intersection prompting picture, therefore, the navigation system of the invention not only can intuitively display the road condition of the next intersection, and too much storage space is not occupied, a large amount of resources are saved, and the compatibility and the transportability of map data among different cities are improved.

Drawings

FIG. 1 is a schematic diagram of a navigation system in the prior art;

FIG. 2 is a schematic structural diagram of a navigation system according to an embodiment of the present invention;

FIG. 3 is a flow chart illustrating a method for navigating an intersection according to an embodiment of the present invention;

FIGS. 4-1 through 4-5 are schematic plan views of an exemplary intersection in accordance with embodiments of the present invention;

FIG. 5 is an abstract intersection picture with pictures coded as 0000001110000111 according to an embodiment of the present invention;

FIG. 6 is a schematic diagram illustrating mapping pole coordinates of a turning indication graph according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of an indicating graph in an embodiment of the present invention;

FIG. 8 is an explanatory diagram of picture coding according to an embodiment of the present invention;

fig. 9 is a view illustrating an example of encoding a synthesized picture of a turn signal picture into an 0000001110000111 abstract picture of an intersection according to an embodiment of the present invention.

Detailed Description

The invention is further described with reference to the drawings and the preferred embodiments.

Among many intersections, intersections with 4 branches and less than 4 branches account for more than 95% of the total amount of the intersections, and most intersections have the same exit number and form, so that many intersections with the same exit number and similar form can be navigated by taking a 3D abstract picture of road form data capable of reflecting information such as current road bifurcation, elevation and the like as an intersection prompting picture. Therefore, the road shapes of a plurality of intersections with the same exit number and shape can be abstracted, and one abstract picture with the same road shape information is used as an intersection prompting picture of the intersection. Therefore, all intersections with the same or similar road forms can be represented by only one abstract picture, and therefore the number of pictures needing to be stored in the picture database is reduced to a great extent. Because the road form types of the intersections below 4-fork and 4-fork are only limited, the function of displaying the scene pictures of the intersections below 4-fork and 4-fork for navigation can be realized by at most hundreds of pictures, and the storage space, the development expenditure and the workload of developers are greatly reduced. In addition, even if the map data in the navigation system is changed into the map data of other cities or countries, the navigation of the intersection can be well supported without changing the abstract pictures in the abstract picture database, and the compatibility and the portability between different map data are improved.

The system structure of the navigation system of the present invention is shown in fig. 2, and includes:

a GPS receiving device 16 for receiving signals from GPS satellites, detecting the current position and moving direction of the vehicle, and converting the detected result into protocol data, which is further sent to a vehicle position detecting module 15 in the navigation module 9 of the control device 6;

a map data module, namely a storage device 2, for storing map data; an abstract picture database 201 storing 3D abstract pictures, an abstract picture database address query module 203 and an indication graph database 202;

display means for displaying navigation information;

the control device 6 comprises a navigation module 9, wherein the navigation module 9 comprises a route guide module 12, and a vehicle position detection module 15 of the navigation module 9 sends data which are obtained from a GPS receiving device 16 and represent the current vehicle position to a map data management module 8, a map display module 11 and the route guide module 12; the route guidance module 12 calculates navigation information according to the position information of the vehicle obtained by the vehicle position detection module and map data stored in the middle of the map data module, and sends the navigation information to the display device 5; the map data management module 8 of the control device 6 reads out the map data and the data content for picture guidance from the storage device 2 in response to the request of the navigation module 9; the map display module 11 of the navigation module 9 generates display data for map display and picture display data based on the map data information and the picture information read from the map data management module 8, and sends the display data and the picture display data to the user interface control module 7.

Wherein, the storage device 2 stores map data, control program data, abstract picture database 201 for displaying the navigation information of the crossroad, picture database address database 203, and indication graphic database 202 for storing various indication graphic pictures; abstract pictures reflecting various different intersection road forms are stored in the abstract picture database 201; the road form navigation information displayed by any two abstract pictures is different. The road form comprises the number of road intersections of the intersection, information of included angles between each non-driving road intersection and the driving road intersection, and information of elevation change of each road at the intersection. The picture database address library 203 links picture codes of abstract pictures of various intersections in the abstract picture database 201, the storage addresses of the abstract pictures and the indication graphic addresses corresponding to the abstract pictures of the intersections. The storage means 2 restores all these data to digital data and sends them to the control means 6.

The route guidance module 12 is provided with an intersection search module 1201, an intersection distance (time) calculation module 1202, a threshold judgment module 1203, a direction calculation module 1204, an elevation calculation module 1205, a code generation module 1206, a picture calling module 1207, and an indication graph drawing module 1208.

The intersection searching module 1201 searches for the next intersection according to the current position determined by the system recommended route vehicle position detecting module searched by the route searching module;

the intersection distance (time) calculation module 1202 of the route guidance module 12 calculates the distance (time) from the current position to the intersection based on the current position of the vehicle position detection module 15, the next intersection searched by the intersection search module, and the current driving speed;

the threshold value judging module 1203 of the route guidance module 12 monitors the route guidance module in real time to detect whether the navigation calculation point of the next intersection is reached by comparing the distance (time) from the current position to the intersection with the preset threshold value size of the navigation calculation point; when the distance (time) from the current position to the intersection is smaller than a threshold value, namely the distance reaches the navigation calculation point of the next intersection, starting a direction calculation module, an elevation calculation module and a code generation module; the navigation display point for reaching the next intersection is that the navigation system enters an intersection abstract map mode and displays navigation information of an intersection prompt picture aiming at the road form of the next intersection.

The navigation calculation point can be set in two schemes, one scheme is that in the scheme, the navigation calculation point is set at a certain distance, such as 500 meters, away from the next intersection, the distance is set as a distance threshold value, or a certain time ahead is set as a time threshold value, and whether the navigation calculation point is reached is judged according to the current driving speed; the threshold value can be preset for a program, and can also be generated in real time for the program according to the current speed, weather conditions and other parameter values. When the distance (time) from the current position to the intersection is smaller than a threshold value, namely the vehicle reaches a navigation calculation point, calculation is started in advance, and when the vehicle reaches a navigation display point of a certain intersection, the navigation system enters an intersection abstract picture mode to directly display a corresponding abstract picture. In this embodiment, in order to simplify the calculation, the point where the navigation calculation point is located is set as the navigation display point, that is, after the navigation calculation point is reached, once the calculation of the navigation information is completed, the navigation information is displayed immediately.

The other scheme is as follows: setting navigation calculation points of all crossroads in the currently generated navigation path at a new navigation path generation position; that is, when a destination is selected and a path is generated, the navigation information of the intersection starts to be calculated, the address of the corresponding abstract picture to be called is found and stored in the cache of the navigation system, and when the navigation display point of a certain intersection is reached, the corresponding abstract picture is displayed. If the vehicle does not drive according to the preset navigation path and walks into other paths, the navigation system needs to regenerate a new navigation path and starts to calculate the navigation information of all the intersections in the new navigation path.

The direction calculation module 1204 of the route guidance module 12 is connected to the map data module, calculates the included angle information between each non-driving road intersection and the driving road in the intersection according to the longitude and latitude of the central point of the next intersection in the electronic map data and the coordinates of each branch point, and obtains the direction type value of each non-driving road intersection according to the corresponding relationship between the included angle information falling into the preset angle interval and the direction type value.

The direction calculation module calculates a connecting line between the angle calculation recording point of the non-driving road intersection and the central point of the intersection and an included angle formed by the connecting line between the angle calculation recording point of the driving road intersection and the central point of the intersection by inquiring longitude and latitude information of the angle calculation recording point and the central point of the intersection in the map data module, so as to obtain an included angle value between the non-driving road intersection and the driving road intersection.

The direction calculation module 1204 determines a direction type value according to an included angle value between each road of the intersection and the driving road. The method for determining the direction type value can be that an interval is divided by a plurality of angles clockwise or anticlockwise according to the directions of each road and the driving road at the intersection, and the road of each interval is defined as a direction type value. The direction type value of the included angle smaller than 90 ° is defined as 001 in the present embodiment; the direction type value of the included angle greater than or equal to 90 degrees and less than 175 degrees is defined as 010; the directional type value of the included angle greater than or equal to 175 degrees and less than 185 degrees is defined as 011; the direction type value of the included angle is more than or equal to 185 degrees and less than or equal to 270 degrees is defined as 100; the direction type value of the included angle larger than 270 degrees is defined as 101; as shown in table 1 below.

Table 1:

the division of the angle section mainly considers that the road right ahead has the largest influence on the vision of people, so that the width of the road has certain influence on the calculation result of the angle, a section with the width of 10 degrees is specially divided for the angle right ahead, and the roads falling into the section are all regarded as roads with an included angle of 180 degrees.

The direction calculation module 1204 obtains an included angle between each non-entering road intersection and the entering road intersection according to the included angle of each road in the current intersection, searches for a corresponding direction type value, and provides the direction type value of each road to the code generation module 1206. (if the effect of the detail degree of the interval division on the abstract picture is not considered, the preset angle interval may be set to other schemes, for example, the direction type value with the included angle less than 85 ° is defined as 001, the direction type value with the included angle greater than or equal to 85 ° and less than 95 ° is defined as 010, the direction type value with the included angle greater than or equal to 95 ° and less than 175 ° is defined as 011, the direction type value with the included angle greater than or equal to 175 ° and less than 185 ° is defined as 100, the direction type value with the included angle greater than or equal to 185 ° and less than or equal to 265 ° is defined as 101, the direction type value with the included angle greater than or equal to 265 ° and less than or equal to 275 ° is defined as 110, and the direction type value with the included angle greater than or equal to 275 ° is defined as 111. in this design, although the number of abstract pictures in the abstract picture database is greatly increased, because many intersections of the four branches are distributed in a cross shape, and the intervals with the width of 10 degrees are divided into the 90-degree road and the 270-degree road respectively, the road form displayed by the abstract picture can be more fit with the actual situation. )

In the abstract picture database, the abstract standard of the abstract picture is the same as the detection standard of the actual intersection, and each combination of the direction type values of all the non-driving road intersections respectively has an abstract picture with the same road form navigation information and a corresponding abstract picture. Drawing the abstract picture to fit the actual situation to the maximum extent, and when one road falls into the certain preset angle interval, setting the road displayed in the abstract picture on an angle bisector of the preset angle interval; when two roads fall into the certain preset angle interval, the two roads displayed in the abstract picture equally divide the angle interval into three parts; and (5) recursion in sequence. Of course, the distribution of the roads in the abstract picture in the preset angle interval can be properly adjusted according to the actual situation.

Elevation calculation recording points are arranged at positions, 50 meters away from the center point of the intersection, of all non-driving road intersections of the intersection; the elevation calculation module 1205 of the route guidance module 12 is connected to the map data module, and by querying the elevation information of the elevation calculation record points in the map data module, the difference between the elevation of the elevation calculation record points of each non-driving road intersection in the next intersection and the elevation of the center point of the intersection is calculated, and the elevation type value of each non-driving road intersection is obtained according to the corresponding relationship between the preset elevation difference range and the elevation type value in which the elevation difference information falls.

In this embodiment, an elevation difference type value of which the elevation difference is greater than or equal to-2 meters and less than or equal to 2 meters is defined as 01, and the elevation type value is represented as a horizontal road surface; defining an elevation difference type value with an elevation difference larger than 2 meters as 10, wherein the elevation type value is represented as an ascending road surface; defining an elevation difference type value of less than-2 m as 11, wherein the elevation type value is expressed as a sinking road surface; as shown in table 2 below.

Table 2:

	more than-2 m and less than or equal to 2m	Greater than 2m	Less than or equal to-2 m
				Type (B)	01	10	11

The 2-meter elevation difference value is mainly set to adapt to the subjective perception law of people, people usually have obvious perception on the elevation difference value of more than 2 meters, obviously, the threshold value of the elevation difference value can be set to other numerical values, and the elevation difference value can be specifically set according to the elevation change of specific road conditions.

In the abstract picture database, the abstract standard of the abstract picture is the same as the detection standard of the actual intersection, and each combination of the direction type value and the elevation type value of the intersection where the non-driving road is located is respectively provided with an abstract picture with the same road form navigation information corresponding to the abstract picture. The 3D abstract picture may be a view observed from a driving angle, or a view that is offset by a certain angle and better reflects the shape of the road at the whole intersection. The view observed from the driving angle can better fit the actual navigation situation of the user, and when the road shape of the whole intersection can be better reflected from other angles, the abstract picture can be the view observed from the preset offset angle.

In this embodiment, in order to simplify the calculation, the elevation calculation recording points and the angle calculation recording points are overlapped, and both the points about 50 meters away from the center point of the intersection are used as the calculation points. The point 50 meters away from the center point is calculated as a calculation point, and the main purpose is to make the perception of the current intersection turning angle consistent with the corresponding abstract picture as much as possible. Particularly, for an actual intersection where a road near the intersection is a curved road, when people subjectively perceive an included angle of an entering road, the angle of the point directly connected with the intersection is not usually selected, but extends a distance into the entering road intersection for perception, and the distance is usually about 50 meters. Therefore, the angle calculation distance is set to 50 meters in the present embodiment. It will be apparent that other values may be chosen depending on actual visibility or other factors.

The code generating module 1206 of the route guidance module 12 searches a road code table (as shown in table 3 below) according to the direction type value and the elevation type value of each non-driving road intersection provided by the direction calculating module and the elevation calculating module, and synthesizes picture codes according to a preset scheme;

table 3:

value of direction type	Elevation type value	Road coding
			10	001	0001
10	010	0010
			10	011	0011
10	100	0100
			10	101	0101
01	001	0110
			01	010	0111
01	011	1000
			01	100	1001
01	101	1010
			11	001	1O11
11	010	1100
			11	011	1101
11	100	1110
			11	101	1111

The picture codes are generated by coding each road of the intersection. The abstract pictures in the abstract picture database are abstract pictures of a three-way intersection and a four-way intersection; the intersection prompting picture of the intersection above the five-fork is represented by a live-action picture, so the present embodiment adopts 12-bit coding, and the coding format is shown in the following table 4:

table 4:

as shown in fig. 8, the number of bits 1-4 where the code is located is the first road code crossing the driving road counterclockwise; the number of the code positions is 5-8, and the code positions are a second road code which is anticlockwise intersected with the driving road; the number of the code positions 9-12 is a third road code which is anticlockwise intersected with the driving road; if the third counterclockwise road is intersected by a non-driving road, the code of the 9-12 bits is 0000.

The picture calling module 1207 of the route guidance module 12 calls the unique corresponding intersection abstract picture and the corresponding instruction graphic picture according to the picture code generated by the code generation module 1206.

The indication graph drawing module 1208 of the path guidance module 12 draws the turning indication graph in the indication graph database on the abstract picture according to the picture called by the picture calling module and the picture parameter. The indication graph can be a graph such as an arrow and the like for marking the direction, and the graph can be dynamic or static.

The map display module 11 generates display data for map display based on the map data information read from the map data management module 8, generates display data for picture display based on the picture data information read from the instruction figure drawing module 1208, and sends the display data to the user interface control module 7.

The user interface control module 7 sends the processing result returned from the instruction graphic drawing module 1208 in the route guidance module 12 to the audio output device 4 and the display device 5.

The display device 5 displays display data for map display and an intersection guidance picture for intersection guidance, which are provided by the user interface control module 7.

For intersections with five or more branches, the intersections can be represented by the 3D abstract pictures drawn in advance or by live-action pictures taken in the field, so as to fit the live-action more closely. The additional workload is not very large due to the limited number of intersections above the five-branch road.

The flow of the navigation method of the intersection is shown in fig. 3:

in step S100, the GPS receiving device 16 receives a signal from a GPS satellite at the signal frequency of the GPS satellite, detects the current position and the moving direction of the vehicle, and converts the detected result into protocol data, which is further sent to the vehicle position detecting module 15 in the navigation module 9 of the control device 6;

in step S101, the vehicle position detection module 15 of the navigation module 9 sends the data indicating the current position obtained from the GPS receiving device 16 to the map data management module 8, the map display module 11, and the route guidance module 12;

in step S102, the intersection search module 1201 searches for a next intersection according to the system recommended route searched by the route search module 13 and the current location determined by the vehicle location detection module 15;

in step S103, the intersection distance (time) calculation module 1202 calculates the distance (time) from the current position to the intersection based on the current position data provided by the vehicle position detection module 15, the next intersection searched by the intersection search module 1201, and the current driving speed;

in step S104, the threshold value judging module 1203 compares the distance (time) from the current position to the intersection with the threshold value, and starts the direction calculating module, the elevation calculating module and the code generating module when the distance (time) from the current position to the intersection is smaller than the threshold value; when the distance (time) from the current position to the intersection is larger than the threshold value, repeating the step S101;

in step S105, the direction calculation module 1204 of the route guidance module 12 calculates an included angle between another intersection and the incoming road of the next intersection, calculates included angle information between another intersection and the incoming road according to the longitude and latitude of the center point of the next intersection and the coordinates of each intersection point in the electronic map data, and obtains a direction type value according to the included angle information;

in step S106, the elevation calculation module 1205 of the path guidance module 12 calculates other branch point elevation changes according to the elevation of the next intersection center point in the electronic map data and the elevation of each branch point, and obtains an elevation type value according to the elevation changes;

in step S107, the code generating module 1206 of the route guidance module 12 generates a picture code according to the direction type value and the elevation type value provided by the direction calculating module and the elevation calculating module;

in step S108, the picture calling module 1207 of the route guidance module 12 searches the picture database address library 203 according to the picture code generated by the code generation module, and calls the unique corresponding intersection abstract picture, the indication graph and the picture parameter corresponding to the outgoing road in the abstract picture database 201 according to the address;

in step S109, the indication graphic drawing module 1208 of the route guidance module 12 compositely forms an intersection prompt picture according to the intersection abstract picture determined by the picture calling module 1207, the turning indication graphic corresponding to the outgoing road, and the picture parameter.

In step S109, the drawing of the steering indication graph (i.e. the steering arrow) has already been described in detail in the application for a method and device for displaying a road supporting a picture and a navigation device (patent application No. 200810065576.0), and therefore is not described herein again.

Certainly, the steering indication graph can also be used as a part of the abstract picture, is directly drawn on the abstract picture and is stored in the abstract picture database; for a four-branch road junction, three abstract pictures with different navigation information (namely, different directions indicated by turning arrows) are required to reflect the same road form. Compared with the mode of separately drawing the turning indication graph, the setting increases the number of the abstract pictures stored in the abstract picture database, and reduces the steps of subsequent redrawing and synthesizing. This solution still allows to implement the invention very well.

The following describes how the navigation device finds the abstract picture corresponding to the road shape navigation information of the actual intersection in the abstract picture database by using an example of the actual intersection.

Fig. 4-1 to 4-5 are schematic views of an actual intersection.

In the electronic map database, roads are usually represented by recording points of the roads in which attribute information such as longitude, latitude, elevation and the like is recorded in the recording points of the roads by road coordinates, and the recording points of the roads are represented by O shown in fig. 4-1 to 4-5₁Dots, O₂Dots, O₃Dot, A₇To A₁Dot, B₁To B₃Dots, and C₁To C₃And D₁To D₂A point wherein O₂The point is an intersection central point formed by crossing the current intersection with the driving road intersection in the current intersection; o is₁Dots, O₃The point is an intersection central point formed by crossing other non-driving road intersections and the current intersection. When the system is running at O₂An road is driven to the O from An point₂At the time of the spot, the system GPS receiving device 16 receives the GPS signal, converts the detected result into protocol data, and sends the protocol data to the own vehicle position detecting module 15 in the navigation module 9 of the control device 6. The vehicle position detection module 15 sends data indicating the current position to the map data management module 8, the map display module 11, and the route guidance module 12.

The threshold value determining module 1203 compares the distance from the current position to the intersection with the threshold value, and when the distance (time) from the current position to the intersection is greater than the threshold value, repeats step S101, that is, waits for the protocol data generated by the next GPS signal, and the vehicle position detecting module 15 sends the data indicating the current position of the next GPS signal to the map data management module 8, the map display module 11, and the route guidance module 12. Until the distance from the current position to the intersection is smaller than the threshold value according to the data of the current position represented by the GPS signal, the direction calculation module 1204, the elevation calculation module 1205 and the code generation module 1206 are started.

At this time, the direction calculation module 1204 gives only part of the exemplary data as shown in table 5 based on the intersection map data provided by the map data management module 8.

Table 5:

first, the direction calculation module 1204 determines calculation record points according to the intersection map data, that is, selects elevation calculation record points for calculating the difference between the angles of other branches and the entering road and the road elevation. The direction calculation module 1204 calculates the direction of the intersection based on the intersection map data because of O₂The point is the central point of the driving road at the intersection, and A is calculated in sequence₁O₂And | A₁O₂-50|、A₂O₂And | A₂O₂-50|.....A_nO₂And | A_nO₂-50|, choosing | A_nO₂-50| A of minimum_nAs the calculation record point, assume that this embodiment selects A₂And (4) point. In the same way, give B₂Dots, C₃And D₁The point is a calculation recording point. And provides these calculation record points ID to the elevation calculation module 1205. The direction calculation module 1204 calculates the included angle between each road of the intersection and the driving road. The direction calculation modules 1204 calculate A respectively₂O₂And O₃B₂As shown in fig. 4-3, the included angle of (a) is 95 °; a. the₂O₂And O₃C₃As shown in fig. 4-4, the included angle of (a) is 179 °; a. the₂O₂And O₁D₁As shown in fig. 4-5, the included angle of (c) is 181 °.

The direction calculation module 1204 determines a direction type value according to an included angle value between each road of the intersection and the driving road. The counterclockwise first road direction type is 010, the counterclockwise second road direction type is 011, and the counterclockwise third road direction type is 011. The direction type values for each road are provided to the code generation module 1206.

The elevation calculation module 1205 obtains O from the calculation record point ID provided by the direction calculation module 1204₁Dots, O₂Dot, A₂Dot, B₂Dots, C₃And D₁And (4) calculating the height difference between the recorded point and the center of the intersection respectively. B is obtained by calculation₂Point relative to O₃The height difference of the points is 0.3 meter, the height difference of the point C3 relative to the point O1 is 0.1 meter, and the height difference of the point D1 relative to the point O1 is 3 meters. The elevation difference type value is determined according to the elevation difference. According to a preset rule, the elevation calculation module 1205 finally determines that the elevation difference type of the counterclockwise first road is 01, obtains the elevation difference type of the counterclockwise second road 10, and obtains the elevation difference type of the counterclockwise third road as 01. The elevation difference values for each road are provided to the code generation module 1206.

The code generating module 1206 searches the road code table (table 3) according to the values sent from the direction calculating module 1204 and the elevation calculating module 1205. Since the counterclockwise first road direction type is 010 and the elevation difference type is 01, the corresponding road code is 0111, the counterclockwise second road direction type is 011, the elevation difference type is 01, the corresponding road code is 1000, the counterclockwise third road direction type is 011 and the elevation difference type is 10, and the corresponding road code is 0011.

The resulting picture from the code generation module 1206 is encoded as 001110000111.

The picture call module 1207 searches the picture database address library 203 according to the picture code 001110000111, as shown in table 6.

Table 6:

wherein,

the NSZ1 is a first road which is intersected with the driving road in a counterclockwise mode;

the NSZ2 is a second road which is intersected with the driving road in a counterclockwise mode;

NSZ3 is the third road that intersects the incoming road counterclockwise.

The offset address of the coded picture is found to be 32C from table 6, and the abstract picture corresponding to the calculated road shape of the current intersection is called, as shown in fig. 5. And simultaneously, the abscissa of the indication graph mapping pole of the road NSZ2 on the graph is 73, and the ordinate of the indication graph mapping pole is 81, as shown in FIG. 6. The offset address of the indication graphic is B97. The picture calling module 1207 finds the offset address of the indication graph according to the graph database address table, and calls the indication graph shown in fig. 7.

The indication graph drawing module 1208 draws the indication graph onto the intersection abstract picture according to the indication graph mapping pole coordinates to form a final guidance graph as shown in fig. 9.

The user interface control module 7 displays the processing result returned from the instruction figure drawing module 1208 in the apparatus 5.

The display device 5 displays display data for displaying a picture for map display, which is provided by the user interface control module 7.

The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.

Claims

1. A navigation method of an intersection is characterized by comprising a calculation process and a display process,

the calculation process comprises the following steps:

the display process comprises the following steps:

2. The intersection navigation method according to claim 1, wherein the step of detecting road form navigation information of the next intersection in step B includes:

In the step B1, an included angle formed by a connection line between the angle calculation recording point of all non-driving road intersections and the intersection center point and a connection line between the angle calculation recording point of the driving road intersections and the intersection center point is used as included angle information.

3. The intersection navigation method of claim 2, wherein elevation calculation record points are provided at a second preset distance from the intersection center point of all non-driving roads of the intersection, and the step B of detecting the road form navigation information of the next intersection further comprises:

in the step D, finding the abstract picture matched with the elevation type value in the abstract picture database according to the elevation type value obtained in the step B4 as the intersection prompt picture.

4. The intersection navigation method of claim 3, wherein, in step B, after step B4, the method further comprises:

5. A navigation system using the method for navigating an intersection according to claim 1, comprising:

the map data module is used for storing map data;

display means for displaying navigation information;

it is characterized in that the preparation method is characterized in that,

the map data module also comprises an abstract picture database used for displaying the navigation information of the intersection, and different abstract pictures reflecting the combination of the direction type value and the elevation type value are stored in the abstract picture database.

6. The navigation system of claim 5, wherein the road shape includes the number of road intersections at the intersection and information of an included angle between each non-entering road intersection and the entering road intersection;

the path guide module comprises:

7. The navigation system of claim 6, wherein each road of the intersection is provided with an angle calculation recording point at a first predetermined distance from the intersection center point, and the direction calculation module calculates a connection line between the angle calculation recording point of the non-entering road intersection and the intersection center point by inquiring longitude and latitude information of the angle calculation recording point in the map data module, and forms an angle with the connection line between the angle calculation recording point of the entering road intersection and the intersection center point as the information of the angle between the non-entering road intersection and the entering road intersection.

8. The navigation system of claim 6, wherein the distribution of the predetermined angular interval is: the first interval is (0-90 degree), (the second interval is (90-175 degree), (the third interval is (175-185 degree), (the fourth interval is (185-270 degree), and the fifth interval is (270-360 degree)).

9. The navigation system of claim 6, 7 or 8, wherein the road morphology navigation information further includes elevation change information of each road at the intersection; all non-driving road intersections of the intersection are provided with elevation calculation recording points at a second preset distance from the intersection central point,

the path guiding module further comprises:

the elevation calculation module is connected with the map data module, calculates the difference value between the elevation of each non-driving road intersection elevation calculation record point in the next intersection and the elevation of the intersection center point by inquiring the elevation information of the elevation calculation record points in the map data module, and obtains the elevation type value of each non-driving road intersection according to the corresponding relation between the preset elevation difference value range in which the elevation difference information falls and the elevation type value;

in the abstract picture database, each combination of the direction type value and the elevation type value of all the non-driving road intersections respectively has an abstract picture with the same road form navigation information corresponding to the abstract picture.

10. The navigation system of claim 9, wherein the predetermined range of elevation difference values corresponds to an elevation-type value as follows: when the elevation difference value is greater than or equal to-2 m and less than or equal to 2m, the elevation type value is expressed as a horizontal road surface; when the elevation difference value is larger than 2m, the elevation type value is expressed as an ascending road surface; and when the elevation difference value is less than-2 m, the elevation type value is expressed as a sinking road surface.

11. The navigation system of claim 9, wherein the route guidance module further comprises:

12. The navigation system of claim 5, wherein the map data module further includes an indication graphic database storing a turn indication graphic, and the route guidance module further includes an indication graphic drawing module for drawing the turn indication graphic in the indication graphic database on the abstract picture.

13. The navigation system of claim 5, wherein the abstract picture is a view from a driving-in angle or a view from a predetermined offset angle.

14. The navigation system of claim 5, wherein the abstract pictures in the abstract picture database are abstract pictures at a three-way intersection and a four-way intersection; the map data module also comprises a live-action picture database for storing live-action pictures of intersections with more than five branches.