System and program

Abstract

To make it possible to extract warning targets that are likely to actually become warning targets.SOLUTION: A system includes: a GPS receiver 8 that detects a position of a vehicle: a database 19 that stores position information of a warning target and road network information; and a control unit 18 that controls notifications to a display unit 5 or the like when the position information of the warning target and a current position of the vehicle have a predetermined proximity relation. The control unit uses the road network information to determine a recommended route from an own vehicle position to a warning target existing in the periphery, and determines whether or not there is the proximity relation based on a travel distance when the vehicle travels along the determined recommended route.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a system and a program for notifying information regarding an approach when a current position comes into a predetermined approach relationship with an object to be alarmed.

Background Art

[0002] In recent years, a large number of vehicle speed measurement devices for measuring the speed of automobiles have been installed on the roadside and the like. As an example of a vehicle speed measurement device, microwaves in a predetermined frequency band are emitted toward a vehicle, and the reflected wave is received to measure the traveling speed of the vehicle.

[0003] In order to detect the presence of such a vehicle speed measurement device, a microwave detector configured to detect microwaves emitted from the vehicle speed measurement device and output an alarm has been conventionally known.

[0004] In addition, some vehicle speed measurement devices cannot be detected by conventional microwave detectors. For example, as called a loop type, a loop-shaped coil is embedded in the ground, and it is configured to detect that a vehicle passes over the coil and also determine the vehicle speed. There are also those that detect the speed of a vehicle using light other than microwaves. Therefore, in advance, the installation position information of the vehicle speed measurement device is stored, and when the current position acquired by GPS (Global Positioning System) or the like approaches the stored installation position (when it comes into a predetermined approach relationship), there is an in-vehicle electronic device such as a radar detector that issues a warning regardless of the presence or absence of microwave detection (Patent Document 1). Since these various vehicle speed measurement devices are installed at locations where traffic accidents frequently occur or where it is easy to exceed the speed and induce traffic accidents, by notifying the driver of those locations in advance, it is possible to encourage safe driving while observing traffic rules especially at particularly dangerous locations.

[0005] As specific notification modes, for example, relative positional relationships such as "Highway H system 1 km ahead to the left", "General road N system just ahead", etc., or content specifying the target content is output as voice information from a speaker, or characters or images representing them are displayed on a display unit.

[0006] In addition, the warning targets include various things such as fixed vehicle speed measurement devices, N systems (automobile number automatic reading devices), accident-prone areas, various enforcement areas, checkpoint areas, etc., and the target to be warned can be selected according to the setting.

[0007] By the way, as one of the conditions for the registered warning target to be actually warned, the current position and the position of the warning target may be in a predetermined proximity relationship. Specifically, the straight-line distance between the current position and the position of the warning target is obtained, and the straight-line distance is set to be less than or equal to a reference value r (for example, 2 km, 1 km, etc.). Thereby, the warning targets existing within the circle with a radius of r centered on the current position are extracted as the actual warning targets.

[0008] At this time, there are often a plurality of warning targets around the current position. In such a case, one warning target that meets the predetermined conditions is taken as the target object, and for that target object, warning information indicating the relative positional relationship as described above is notified. Also, when a display unit is provided, an object indicating the own vehicle is drawn at a predetermined position on the display screen, and when a warning target exists within the space displayed on the display screen, an object of that warning target is drawn at the corresponding position on the screen. At this time, at the position of the warning target that becomes the above-mentioned target object, an object in a different mode from the objects of other warning targets is drawn so that it can be known that it is the target object. By changing the drawing mode of the object in this way, the driver can recognize the existence of the warning target that is the target object among the plurality of warning targets (objects) drawn on the display screen and know the relative positional relationship with the own vehicle position.

Prior Art Documents

Patent Documents

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-64588 [Summary of the Invention] [Problems to be Solved by the Invention]

[0010] One of the conditions for extracting a warning target, the proximity relationship, is determined based on the straight-line distance between the current position and the position of the warning target. Therefore, for example, a warning target installed on a road different from the currently traveled road is notified as a warning target if it is at a straight-line distance of a predetermined distance or less from the current position. However, since the notified warning target is not installed on the currently traveled road, the vehicle will not pass in front of the warning target even if it continues to travel. That is, this warning is an unnecessary warning. By receiving such an unnecessary warning, the driver will have unnecessary worries. Furthermore, since the vehicle does not pass in front of the warning target, there is a risk that the driver will be in an anxious state without being able to actually find the warning target and confirm the passage. Also, when such a different road is parallel to and relatively close to the currently traveled road, if the objects of the vehicle's own position and the warning target are respectively drawn on the display screen, since the object of the warning target is drawn in front of the traveling direction, there is a risk of misrecognizing that there is a warning target on the road on which the vehicle is traveling. In particular, when the display screen is small, the risk of misrecognition becomes higher.

[0011] Also, for example, when the road ahead while driving curves significantly and there is an object of warning ahead of the curve of the road, if the objects are drawn at the position of the own vehicle and the position of the object of warning on the display screen, the object of the warning will be drawn at a position far from the front in the traveling direction. Therefore, the driver may misrecognize that it is on a road different from the road being traveled just by a glance. Conversely, when the current road is a straight road and there is a curve ahead, and there is an object of warning on a road different from the road being traveled on the extension line of the straight road, if the objects are drawn at the position of the own vehicle and the position of the object of warning on the display screen, since the object of the warning will be drawn ahead in the traveling direction, there is a risk of misrecognizing that there is an object of warning ahead of the road being traveled. In particular, in the case of an inexpensive product that does not store map information, since the map cannot be displayed when storing the position information of the point of the object of warning and displaying the position of the point, the problem of misrecognition becomes significant.

[0012] Also, as the notification content of the object of warning, there is one equipped with a function of notifying the remaining distance to the object of warning. This remaining distance is based on the above-mentioned straight-line distance. And when the vehicle actually travels, not only when the road curves, but also when turning right or left at an intersection on the way to change the course. Therefore, the object of warning is often not on the extension line of the current traveling direction, the difference between the degree of decrease in the remaining distance and the actual traveling distance is different, and a sense of discomfort occurs according to the degree of decrease in the remaining distance.

[0013] Furthermore, the distance traveled before actually arriving in front of the warning target is naturally longer than the straight-line distance. And as described above, when repeatedly turning right or left from the current position until actually reaching the warning target, when the road has a large curve, when driving according to the road network conditions, one-way traffic, and other traffic regulations, the difference can be very large. Then, a long distance will be traveled and it will take time from when the warning is first issued until actually arriving at the warning target. As a result, the driver, although there is a warning, can hardly visually recognize and confirm the warning target, and there is not only a risk of being suspicious of the warning, but also a risk of reaching the warning target after misjudging the warning as incorrect. Also, in many cases, the driver does not actually go to the location of the warning target where one arrives only after repeatedly turning right or left. In such a case, it is not preferable to issue a useless warning.

[0014] On the other hand, combined with increasing the types of warning targets registered in the database, the number of warning targets existing around the current position also becomes large. If all of them are displayed, it will be full of warning target objects, and there is also a problem that the presence and position of the target object become difficult to understand. Also, in order to reduce the number of warning targets to be warned, measures such as registering in advance the types to be notified, or setting as warning targets those existing within a fan-shaped area in front of the traveling direction and within a predetermined angle are taken.

[0015] However, in the former case, if the warning types are narrowed down more than necessary, various warning targets that have been registered with great effort cannot be notified. Also, in the latter case, warning targets existing at the end of a road with a large curve or at the end of a turn at an intersection may be located outside the fan shape and cannot be warned.

[0016] Thus, there is a problem that conventional in-vehicle electronic devices of this type have not been able to sufficiently extract warning targets existing around and issue warnings. Also, when notifying detailed warning information about a predetermined warning target (target object) when there are multiple warning targets, there is also a problem that the driver wants to easily know which warning target the notification is about.

Means for Solving the Problem

[0017] In order to achieve the above object, an in-vehicle electronic device according to the present invention is a system including: (1) a position acquisition means for acquiring the current position of a vehicle; and a control means for performing notification control on a notification means when there is a predetermined proximity relationship between the current position of the vehicle acquired by the position acquisition means and the position information of an alarm target acquired by accessing a position storage means for storing the position information of the alarm target. In the system, the control means accesses a map data storage means for storing road network information, obtains a route from the current position of the vehicle to the alarm target using the obtained road network information, and determines the presence or absence of the proximity relationship based on the obtained route.

[0018] In the embodiment, the position acquisition means corresponds to the GPS receiver 8. The position acquisition means of the present invention includes not only those acquired by a position detection means for detecting the current position like the GPS receiver in the embodiment, but also those having a function of acquiring position information about the current position of the vehicle from an external device, equipment, etc. Examples of such external devices, equipment, etc. include electronic devices having a position detection function (GPS receiver) such as a car navigation device, and a GPS antenna unit.

[0019] In the embodiment, the map data storage means corresponds to the database 19. Thus, it may be built in the device, or some or all of the information may be stored in an external device such as a server, and the necessary information may be acquired by accessing the server through communication.

[0020] The route corresponds to the recommended route in the embodiment. It is advisable to use the one commonly used in the car navigation system for this recommended route. Among the several routes from the current position to the destination, it is determined to be the one with the shortest driving distance or the one that can be reached in the shortest time. At this time, the type of road to be traveled (priority road / general road) may be specified, and a route that meets the conditions may be determined. In the present invention, such car navigation technology can also be used, or alternatively, a route to the warning target may be obtained based on other conditions.

[0021] The determination of the conventional proximity relationship was obtained based on the straight-line distance connecting the current position and the warning target. However, in the present invention, the determination is made based on the route obtained using the road network information. The determination based on the route should be made, for example, based on more practical driving conditions and situations such as whether the warning target exists ahead of the road on which the vehicle is actually traveling or on another road, and whether it is easy to reach the warning target from the current position. In this way, even when there are a large number of warning targets registered around the vehicle, the one that conforms to the actual driving is determined to have a "predetermined proximity relationship". Therefore, the user can know a more appropriate one among the large number of warning targets existing around the vehicle.

[0022] (2) The control means may obtain the distance traveled when traveling along the route, and determine the presence or absence of the proximity relationship based on the distance. From the state of the road network, that is, conditions such as whether it is a straight road or a curved road, the position of intersections, and traffic rules such as one-way traffic and no right turn, the straight-line distance from the current position to the warning target and the distance traveled when traveling along the route to reach the warning target (travel distance) are different. And the distance is longer than the straight-line distance, but the difference also varies greatly depending on the situation. Even if there is a warning target with a short straight-line distance, until reaching there, it may take a long time to travel a long distance by detouring or the like, and the need to issue a warning immediately is low, and the possibility of actually going to the location of the warning target is also low. On the other hand, for a warning target with a short distance traveled along such a route, since it may reach relatively soon, it is preferable to issue a warning. By judging the proximity relationship based on the distance traveled until reaching the warning target through the route and controlling the warning in this way, it is possible to extract and notify the warning target for which a warning should be appropriately issued.

[0023] (3) The control means may obtain the time required when traveling along the route, and determine the presence or absence of the proximity relationship based on the time. The time may be calculated using, for example, probe information on traffic congestion conditions obtained by VICS or communication. When it takes a long time to reach the warning target, the urgency to issue a warning is low, and conversely, when the time is short, the urgency to issue a warning is high. Therefore, it is advisable to determine the presence or absence of the proximity relationship based on the time.

[0024] (4) The control means may be configured to determine the number of intersections at which the vehicle turns when traveling along the route, and determine the presence or absence of the approaching relationship based on that number. In the route from the current position to the warning target, the more intersections (right or left turns) there are, the more complex the route to the warning target becomes. Therefore, it can be said that the lower the possibility of actually reaching the location of the warning target via a more complex route. That is, if the possibility of actually reaching the location of the warning target is low, it can be said that, even if the straight-line distance or the like is short, in terms of the driving situation at that time, the vehicle is not approaching (the approaching relationship is low or non-existent). By thus determining the approaching relationship based on the number of turning intersections and controlling the warning, it is possible to extract and notify the warning target to which a warning should be appropriately issued.

[0025] (5) In the invention of (4), the control means may be configured such that warning targets with two or more turns at intersections are not given a normal warning. For example, when a warning target exists on another road parallel (substantially parallel or non-intersecting) to the road currently being traveled, in order to travel on such another road, it is necessary to turn once at an intersection on the currently traveled road to deviate from the currently traveled road, and further, to enter the other road, it is necessary to turn once at an intersection of that other road. Therefore, in order to travel on such another road, it is necessary to turn at intersections at least twice. In other words, when there is a relationship of turning at intersections two or more times before reaching the warning target, it means that the warning target exists on another parallel road or passes through a complex route, and the possibility of reaching such a warning target is low. Therefore, by doing so as in the present invention, even if the distance to the warning target (straight-line distance and / or distance when traveling along the route) is short, it is possible to effectively exclude warning targets existing on other parallel roads or the like. Not giving a normal warning includes not only not giving a warning but also, for example, reducing the level of the warning. Reducing the level means, for example, drawing an object in a less conspicuous manner at the position of the warning target compared to a normal warning target, or not outputting detailed warning information associated with the warning target even if an object is drawn at the position of the warning target.

[0026] (6) The control means may extract, as warning target candidates, warning targets existing in a circular or sector-shaped area with a set predetermined distance radius centered on the current position from the current position and the position information of the warning target, obtain the route to the extracted warning target candidates, and determine the warning target to be notified by the notification means based on the obtained route. By narrowing down the target for which the route is to be obtained, the load on the control means can be reduced. The sector-shaped area serving as the criterion for extracting the warning target candidates may be a sector-shaped area with a radius r and a central angle θ with respect to the traveling direction of the vehicle.

[0027] (7) The predetermined distance may be set to be equal to or less than the distance at which the presence of the approach relationship is determined based on the distance when traveling the route. The distance assuming traveling along the road of the route from the current position to the warning target is equal to or longer than the straight-line distance from the current position to the warning target. Therefore, by setting the predetermined distance to the distance at which the approach relationship is considered to exist, it is possible to prevent extracting as warning target candidates those that cannot be warning targets for which a warning should be issued. Furthermore, the traveling distance and the straight-line distance are equal when the warning target is connected to the current position of the vehicle by a single straight road, and in many cases, the straight-line distance is shorter. Therefore, by setting the predetermined distance to be shorter than the distance at which the approach relationship is considered to exist, the number of candidates extracted as warning target candidates can be appropriately reduced.

[0028] (8) In the case of a warning target for which it is better to issue a warning when the warning target approaches from a specific direction, direction information indicating the specific direction is registered in a predetermined storage means in association with the warning target, and the control means determines whether to issue a normal warning based on the traveling direction of the vehicle when traveling the route and passing through the road where the warning target is installed and the direction information.

[0029] When a vehicle is approaching a warning target, there are warning targets for which it is better to issue a warning regardless of the direction from which the vehicle is approaching the warning target, and warning targets for which it is better to issue a warning when approaching from a specific direction. For example, warning targets for which it is better to issue a warning regardless of the approaching direction without directionality include drowsy driving accident locations, no-parking monitoring areas, intersection monitoring points, accident-prone areas, areas with frequent vehicle-targeting incidents, etc. On the other hand, in the case of devices and systems for monitoring vehicles such as a vehicle speed measurement device or an N system, there are monitoring areas and monitored lanes (uphill lane / downhill lane). When approaching from the opposite direction, since the monitoring area and lane are not passed through, the necessity of issuing a warning is low. The speed limit switching point is also a point where the speed limit switches to the lower side, so it is usually set on one side of the uphill lane or downhill lane. Therefore, when traveling in the opposite lane and approaching the warning target, the necessity of issuing a warning is low. Thus, when the necessity of issuing a warning changes depending on the direction when approaching the warning target, by registering direction information for specifying the approaching direction in association with the warning target, when finally arriving immediately before the warning target through the route, if the traveling direction of the vehicle at that time and the direction specified by the direction information registered for the warning target do not have a desired relationship, it is possible not to issue a normal warning.

[0030] That is, when direction information is registered, what is important is not the relationship with the traveling direction of the vehicle at the current position, but the traveling direction of the vehicle immediately before the warning target. In the present invention, there is road network information and the traveling direction of the vehicle immediately before the warning target can be known. Therefore, it is possible to determine whether the direction specified by the direction information of the warning target and the traveling direction of the vehicle immediately before are in an appropriate relationship, and a correct warning can be issued.

[0031] Note that the storage means for registering this direction information may be the same as (partially incorporated into) the position storage means, or it may be separate. And this storage means may also be implemented within the device equipped with the control means, or it may be realized as a storage device such as a server outside the device. This specific direction corresponds to the installation direction in the embodiment. That is, since the specific direction is set based on the direction in which the device is installed (the direction specifying the monitoring area), in the embodiment, the installation direction is assumed based on the case where the warning target is the device, but it does not prevent the case of a warning target other than the device from being defined as the specific direction.

[0032] (9) When the warning target is a case where it is better to issue a warning when approaching from a specific direction, the direction information indicating the specific direction is registered in a predetermined storage means in association with the warning target. For the route, on the road where there is a warning target with direction information set, it is preferable to select a route that proceeds toward the installation direction as the direction approaching the warning target. By doing so, it is possible to exclude a route that approaches from a direction different from the original specific direction for the warning target.

[0033] (10) The control means controls the warning according to the remaining distance to a predetermined warning target, and the remaining distance is preferably set to be equal to or less than the distance when traveling from the current position to the predetermined warning target along the route. In this type of system, the remaining distance to the warning target is displayed numerically, by an indicator, etc., the background color of the display unit is changed, or the remaining distance is announced by voice. In this case, by using the travel distance, it is possible to issue a warning based on the remaining distance at an appropriate timing that better conforms to the actual situation.

[0034] (11) The notification means includes a display unit, and the control means draws a road map based on the road network information on the display unit, and draws objects corresponding to the current position and the existence position of the warning target on the road map, respectively. Further, it is preferable to draw a guide line connecting the object indicating the own vehicle drawn at the current position and the object indicating the warning target along the obtained route. Since the guide line is drawn along the road, the driver can immediately understand whether the route to the warning target is the road on which the driver intends to drive, and can intuitively understand whether the warning target requires attention. Further, this guide line is preferably drawn in an animation so that it gradually extends along the road from the position of the own vehicle and finally reaches the object of the warning target. Further, as long as the positional relationship between the current position and the warning target is known, the tip of the guide line does not have to be directly connected to each of the object indicating the own vehicle and the object indicating the warning target.

[0035] (12) The notification means includes a display unit, and the control means draws a display board for displaying information about the warning target on the display unit. When there are a plurality of warning targets, it is preferable to draw the respective display boards for the plurality of warning targets such that the one with the higher set priority comes to the front side. It is preferable because the existence of a plurality of warning targets and their order can be understood at a glance.

[0036] (13) The program of the present invention is a program for causing a computer to realize the functions of the control means in the in-vehicle electronic device according to any one of (1) to (12) above.

Effects of the Invention

[0037] According to the present invention, it is possible to extract warning targets that are highly likely to actually reach the warning target, appropriately narrow down the surrounding warning targets to be warned and notified, and issue warnings for those narrowed-down warning targets. By narrowing down the warning targets to be warned, for example, even when indicating the positions of the warning targets on the display unit, the number of displays is small, so it is easier for the driver to confirm individual warning targets. Furthermore, by devising the drawing, when notifying detailed warning information about a predetermined warning target (object), the driver can easily understand which warning target the notification is about.

Brief Description of the Drawings

[0038]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0039] Figures 1 and 2 show the configuration of a radar detector, which is a preferred embodiment as an electronic device constituting the system of the present invention. This radar detector is usually mounted on the dashboard. As shown in Figure 1, on the upper surface of the case body 1, a solar panel 2 and a switch section 3 are arranged, and inside the front side of the case body 1, a microwave receiver 4 for detecting microwaves in the frequency band emitted by the speed measuring device is arranged. On the other hand, on the rear side of the case body 1 (the side arranged towards the rear of the vehicle (the driver's side)), a display section 5, an alarm lamp 6, an infrared communication device 7, and a remote control receiver 16 are arranged. Also, on the upper surface side inside the case body 1, a GPS receiver 8 is arranged. Further, on one side surface of the case body 1, an adapter jack 9 is arranged, and on the other side surface, a power switch 10 and a DC jack (not shown) are arranged. Also, a speaker 20 is built into the case body 1.

[0040] In this embodiment, the display section 5 is a 2.4-inch small liquid crystal display, and the rear side of the case body 1 (the side arranged towards the rear of the vehicle (the driver's side)) is used as the display surface. The height H of the rear side of the case body 1 where the display section 5 is mounted is made larger than the height H0 of other parts.

[0041] As shown in Figure 2, the infrared communication device 7 performs data transmission and reception with a communication device having a built-in infrared communication device such as a mobile phone 12. The adapter jack 9 is a terminal for connecting a memory card reader 13. By connecting the memory card reader 13 to the adapter jack 9, the data stored in the memory card 14 attached to the memory card reader 13 can be taken in internally, or the contents of the memory of the database 19 and the control section 18 can be written to the memory card 14. More specifically, when there is update information such as alarm target information, which is information regarding a new target or other alarm targets, in the data stored in the memory card 14, the control section 18 stores (downloads) the update information in the database 19 built into the device and updates the data in the database 19. Note that the function of the memory card reader 13 may be configured to be built into the main body case 1.

[0042] The database 19 is a non-volatile memory (such as an EEPROM) inside the microcomputer of the control unit 18 or externally attached to the microcomputer. In the database 19, alarm target information, which is information regarding a certain alarm target at the time of shipment, is registered, and data and the like regarding the alarm target added later can be updated as described above. Also, data update can be performed via the infrared communication device 7.

[0043] The DC jack is for connecting a cigar plug cord (not shown), and can be connected to the cigar socket of the vehicle via the cigar plug cord to receive power supply. The wireless receiver 15 receives wireless signals of a predetermined frequency flying in. The remote control receiver 16 performs data communication with the remote control (portable device: sub-unit) 17 by infrared rays and performs various settings for the device. Also, the switch unit 3 is connected to the control unit 18 (not shown) and can perform the same settings as the remote control 17. The remote control 17 is provided with a play button, a standby switch button, a setting button, a selection button, a cancel button, a decision button, and cross buttons for up, down, left, and right.

[0044] Also, the control unit 18 is a microcomputer including a CPU, ROM, RAM, non-volatile memory, I / O, etc., is connected to the above-described respective units as shown in FIG. 2, executes predetermined processing based on the information input from the above-described respective units, and controls the above-described respective units to output predetermined alarms, messages, and information. Note that, basically, the same components as those of the conventional ones can be used for these basic configurations.

[0045] The functions in the radar detector of the present embodiment are stored on the EEPROM of the control unit 18 as a program executed by the computer included in the control unit 18, and are realized by the computer included in the control unit 18 executing this program. The functions realized by the computer by the program included in the control unit 18 include a GPS logging function, a standby screen display function, a radar scope display function, a GPS alarm function, a radar wave alarm function, a wireless alarm function, and the like.

[0046] The GPS logging function is a function in which the control unit 18 associates the current position detected by the GPS receiver 8 every second with the detected time and speed (vehicle speed) and stores it as a position history in the memory card 14. This position history is a function of recording in, for example, the NMEA format. The standby screen display function is a function of displaying the speed, latitude, longitude, and altitude of the own vehicle detected by the GPS receiver 8 on the display unit 5 as shown in Fig. 3(a).

[0047] The radar scope display function is a function of searching for warning targets (also referred to as targets, etc.) within a predetermined range (for example, within a range of about 1 km) from the current position detected by the GPS receiver 8 from the position information stored in the database 19, and displaying the relative positional relationship between the own vehicle position and the warning target position on the display unit 5. In Fig. 3(b), the "W" on the left indicates west, the "E" on the right indicates east, the "N" on the upper side indicates the north direction, and the icon at the intersection of the horizontal line connecting "W" and "E" and the vertical line extending downward from "N" indicates the own vehicle position. Also, icons with characters such as "L", "RD", "P", "N", etc. indicate the type and position (location) of the warning target.

[0048] When the pressing of the standby switching button provided on the remote control 17 is detected during the execution of the standby screen display function as shown in Fig. 3(a), it switches to the radar scope display function as shown in Fig. 3(b).

[0049] During the execution of the standby screen display function or the radar scope display function (hereinafter these functions are collectively referred to as the standby function), the control unit 18 executes processing to realize each function such as the GPS warning function, the radar wave warning function, and the wireless warning function according to the generated event.

[0050] The radar wave warning function is a warning function that, when the microwave receiver 4 detects a signal corresponding to the microwave in the frequency band emitted from a speed measuring device (such as a mobile radar, hereinafter simply referred to as "radar"), displays a warning screen on the display unit 5 and outputs a warning sound from the speaker 20. For example, when the microwave receiver 4 detects the microwave in the frequency band of the microwave emitted by the radar, as shown in FIG. 4, a schematic diagram or a photograph of the radar stored in the database 19 is displayed on the display unit 5 as a warning screen, and the voice data stored in the database 19 is read out to output a voice "There is a radar. Caution for speed" from the speaker 20. While the voice is being output, the warning lamp 6 is lit.

[0051] The wireless warning function is a function that issues a warning when the wireless receiver 15 receives the radio wave emitted by an emergency vehicle or the like so as not to interfere with its running or the like. In the wireless warning function, frequencies such as traffic control radio, car stereo radio, digital radio, very small radio, police activity radio, police telephone, police activity radio, vehicle location radio, helicopter radio, fire helicopter radio, fire radio, emergency radio, highway radio, security radio, etc. are scanned. When a radio is received at the scanned frequency, a schematic diagram indicating that the radio corresponding to that frequency stored in the database 19 for each radio type is received is displayed on the display unit 5 as a warning screen, and the voice data stored in the database 19 for each radio type is read out to output a warning voice indicating the type of that radio from the speaker 20. For example, when traffic control radio is received, a voice such as "There is traffic control radio. Caution for speed" is output. While the voice is being output, the warning lamp 6 is lit.

[0052] The GPS warning function is a process that is executed at a predetermined time interval (1-second interval) by an event from a timer in the control unit 18 during the execution of the standby screen display function in FIG. 3(a) or the radar scope display function in FIG. 3(b). It uses the current position detected by the GPS receiver 8 and the warning target information stored in the database 19 to determine whether the warning condition (a predetermined proximity relationship) is satisfied, and issues a warning when it is satisfied.

[0053] First, an example of the type of warning target is as follows: areas prone to dozing-off driving accidents, vehicle speed measurement devices (radar type / H system / loop coil / LH system), mobile vehicle speed measurement areas, speed limit switching points, enforcement areas, interrogation areas, no-parking monitoring areas, N system, traffic monitoring system, intersection monitoring points, signal violation suppression system, police stations, accident-prone areas, areas with many on-vehicle targets, sharp / continuous curves (expressway), branch / merge points (expressway), ETC lane advance notice (expressway), service areas (expressway), parking areas (expressway), highway oasis (expressway), smart interchange (expressway), gas stations inside PA / SA (expressway), tunnels (expressway), highway radio reception areas (expressway), prefecture boundary notification, road stations, viewpoint parking, etc. There are various types of such warning targets.

[0054] The warning target information stored in the database 19 is information regarding individual warning targets, including position information such as longitude and latitude for specifying the position of the warning target, and warning target specifying information useful for the driver to identify the warning target. In the present embodiment, the position information is absolute position information using longitude and latitude. This is preferable because the relative positional relationship with the current position detected by the GPS receiver 8 can be easily obtained.

[0055] The warning target specifying information includes type information indicating the type of the warning target, character information indicating the position of the warning target, voice information indicating the warning target, image information indicating the warning target, and the like. In the case where the voice information, image information, etc. indicating the warning target correspond to the type information of the warning target, they can be stored not as warning target information for individual warning targets but as common information separately in a predetermined storage area. Then, when giving a warning, the control unit 18 can read out the type information stored as warning target information, acquire the corresponding image information, voice information, etc. from the type target, and output the warning.

[0056] As common image information, there is image data such as a schematic diagram that enables easy understanding of the type of warning target. The schematic diagram is also a mark for enabling intuitive understanding of the type of warning target from vision. For example, there are those created as images in 3D of a vehicle speed device, a police car, a police officer, etc. These schematic diagrams can be drawn and output on the display unit 5 when notifying, so that the driver can intuitively understand the type and content of the warning target currently being notified. Then, as will be described later, it is more preferable to draw the own vehicle icon at the position of the own vehicle on the display area of the display unit 5 and draw the schematic diagram at the position of the warning target location, so that it can be intuitively understood what warning target is at which position.

[0057] Also, the voice information is data for outputting, from the speaker 20, as voice information, relative positional relationships such as "1 km ahead in the left direction, highway H system" and "ahead soon, general road N system", and the type of warning target, etc. In the above example, voice data indicating the relative positional relationship between the current position of the vehicle and the warning target, such as "left direction", "1 km ahead", "ahead soon", etc., and voice data for specifying the type and content of the warning target, such as "general road N system" and "highway H system", are managed and stored separately, and the control unit 18 combines and outputs the respective voice data when notifying.

[0058] By separately managing fixed voice information (voice data), etc. according to the types of these warning targets, it is not necessary to register information of the same content as warning target information for individual warning targets, and the consumption amount of the memory area can be reduced.

[0059] Then, for example, during the execution of the standby screen display function in Fig. 3(a) or the radar scope function in Fig. 3(b), the database 19 is periodically accessed based on the current position. When the distance between the loop coil to be warned and the vehicle becomes any one of 2 km, 1 km, or 500 m, which is the approaching warning distance stored in the database 19, data of a schematic diagram or a photo of the loop coil to be warned is read from the database 19 and displayed on the display unit 5, and at the same time, voice data stored in the database 19 is read out and an approaching notification is performed by outputting a warning voice from the speaker 20. For example, when approaching 500 m, as shown in Fig. 3(c), a radar scope screen similar to Fig. 3(b) is displayed on the right side of the screen to display the positional relationship between the loop coil to be warned and the vehicle position, and data of a schematic diagram or a photo of the loop coil to be warned indicating the loop coil is read from the database 19 and displayed on the display unit 5, and voice data "There is a loop coil 500 m ahead, pay attention to speed" is read from the database 19 and output from the speaker 20. Also, when the warning voice is being output, the warning lamp 6 is lit.

[0060] Furthermore, the database 19 stores map data including road network information. This road network information is data necessary for searching for a recommended route in car navigation or the like, and includes information such as a road network (road layout) and traffic regulations such as one-way traffic. Further, this road network information stores the position information (latitude and longitude) of nodes at intersections or inflection points of roads as nodes, and information indicating which other nodes each node is connected to. Based on the information indicating the connection relationship of each node in this way, adjacent nodes are connected to each other, and the connected nodes form a road link. Note that since it does not guide to a destination like a car navigation device, there is no detailed data such as display data of facilities and houses, and it is simple data.

[0061] In this embodiment, as a condition for giving a proximity warning, it is determined based on whether the distance between the current position and the position of the warning target has reached the proximity warning distance. However, such a distance is not a straight-line distance, but is determined using the distance (travel distance) assuming that the vehicle travels along the route to the warning target obtained based on road data. Specifically, the control unit 18 executes the following processes (1) to (3).

[0062] (1) First, the control unit 18 extracts warning targets existing within a radius r (for example, 1 km, 2 km) from the vehicle position (current position) (Condition 1). This can be executed by the same algorithm as the extraction process of warning targets existing around the current position (a circle with a radius r) based on the conventional straight-line distance, and the extracted warning targets are set as warning target candidates. Here, r is preferably set to be equal to or less than the predetermined proximity distance in the following (3). Since the travel distance assuming that the vehicle travels along the actual road from the current position to the warning target is equal to or longer than the straight-line distance from the current position to the warning target, by setting the r to the proximity distance, it is possible to prevent extracting as warning target candidates those that cannot become warning targets for which a warning should be issued. And the case where the travel distance is equal to the straight-line distance means that the current position of the vehicle and the warning target are connected by a single straight road, and in many cases, the straight-line distance is shorter. Therefore, by setting r to be shorter than the predetermined proximity distance in (3), the number of extracted warning target candidates can be reduced, and it is preferable to reduce the load of performing the processes after (2).

[0063] (2) Next, the control unit 18 executes a route search from the current position to each warning target candidate. This is obtained by using the technology of searching for a recommended route in a car navigation system. That is, each warning target candidate is regarded as the destination in the navigation system, and the position information of each warning target candidate is sequentially set as the position information of the destination, and the recommended route from the current position to the destination is obtained based on the road network information stored in the database 19. Since the database 19 stores, as road network information, the position information of nodes such as intersections and information indicating the connection relationship between each node, the control unit 18 obtains candidates for the route from the current position to the position of the warning target candidate set as the destination via adjacent nodes in sequence, and determines one route that meets the conditions as the recommended route. As the condition for such a recommended route, the one with the smallest distance among each route is set as the recommended route. Also, instead of the shortest distance, a route that reaches in the shortest time may be determined as the recommended route. Furthermore, when searching for a route, various conditions may be added, such as giving priority to general roads or toll roads. As a method for calculating such a recommended route, a known method such as Dijkstra's method can be used. Further, the control unit 18 obtains the travel distance when traveling from the current position to the warning target candidate along the determined recommended route. In the present embodiment, since the route with the shortest travel distance among the routes to the warning target candidate is determined as the recommended route, the travel distance obtained when making such a determination is used.

[0064] (3) The control unit 18 sets, as a warning target to be warned, those for which the travel distance to reach the warning target candidate through the recommended route is within a predetermined approach distance (for example, 2 km) (Condition 2). Further, when the installation direction (monitoring direction) is registered for the warning target, the control unit 18 extracts, as a warning target that satisfies the warning conditions, a warning target for which the travel distance is within the predetermined approach distance and the traveling direction of the vehicle immediately before reaching the warning target candidate by traveling along the recommended route and the installation direction of the warning target, and sets it as a warning target to be warned (Condition 3).

[0065] For example, when the object to be alarmed is a vehicle speed measuring device or the like, there is a monitoring area for measuring the traveling speed of the vehicle. In the case where the vehicle speed measuring device emits microwaves, this monitoring area is within a range of a certain distance from the vehicle speed measuring device within a predetermined angular range to the left and right with respect to the direction in which the antenna that emits the microwaves is facing. Therefore, if the vehicle approaches from the side opposite to the installation direction of the vehicle speed measuring device, the necessity of alarm notification of the presence of the vehicle speed measuring device is low. Thus, by registering the direction of the vehicle speed measuring device (antenna) as the installation direction, it is possible to determine whether or not it is an object to be alarmed that requires an alarm even when the distance to the object to be alarmed candidate is close based on the relationship with the traveling direction of the vehicle. In this way, the installation direction of the object to be alarmed can specify the monitoring area, but it is not limited to the range where microwaves are emitted as described above. For example, when there is an object to be alarmed that monitors only one of the uphill and downhill directions of a road, it is advisable to set the extending direction of either the uphill or downhill road as the installation direction.

[0066] Next, the determination based on the above processes (1) to (3) will be described while showing a specific example. For example, as shown in FIG. 5, it is assumed that there are four objects registered as objects to be alarmed (satisfying condition 1) existing around the current position of the host vehicle G (within a radius r). Then, by executing the process of (1), the control unit 18 extracts these four objects to be alarmed as alarm target candidates K1 to K4. Next, the control unit 18 executes the process of (2) and performs a route search for each of the alarm target candidates K1 to K4. That is, the control unit 18 sets the alarm target candidate K1 as the destination and searches for a recommended route from the host vehicle position. Then, the control unit 18 determines, for example, as shown in FIG. 6(a), a route R1 that turns left at the first T-junction and further turns left at the next crossroads as the recommended route.

[0067] The control unit 18 then sets the warning target candidate K2 as the destination and searches for a recommended route from the vehicle's current position. For example, as shown in Fig. 6(b), after turning left at the first T-junction, it determines a route R2 that goes straight as the recommended route. Similarly, the control unit 18 sets the warning target candidate K3 as the destination and searches for a recommended route from the vehicle's current position, and determines a route R3 as shown in Fig. 6(c) as the recommended route. Since the warning target candidate K3 is set on the highway, a vehicle traveling on a general road will take a route to enter the highway after traveling to the interchange. Further, the control unit 18 then sets the warning target candidate K4 as the destination and searches for a recommended route from the vehicle's current position, and determines a route R4 as shown in Fig. 6(d) as the recommended route.

[0068] After that, the control unit 18 executes the process of (3) and extracts warning target candidates that satisfy condition 2 or condition 3. First, in the determination based on the travel distance traveled until reaching the warning target candidate through a common recommended route in conditions 2 and 3, the warning target candidate K3 on the highway is excluded from the warning target that should actually be warned because the travel distance is much farther than the straight-line distance and is more than the approach distance. By doing so, when the road types of the currently traveled road and the road where the warning target is installed are different, it is possible to exclude the warning target in many cases without determining the match / mismatch of the road types.

[0069] That is, in this type of radar detector, as the actual target for notification, highways / general roads / both can be switched by setting. If "both" is selected and an alarm target for the highway is notified when only driving on general roads, it may be annoying. In this case, only "general roads" can be selected as the notification target, but such setting switching is complicated and there is also a risk of misconfiguration. Similarly, when driving on a highway, it may also be annoying to be notified of an alarm target installed on a parallel general road or the like. In this case, only the "highway" can be selected as the notification target, but such setting switching is complicated and there is also a risk of misconfiguration. Furthermore, for example, when an alarm target is set at a location on a general road relatively close to the exit of a highway, if the alarm target to be notified is set only for the highway, the existence of the alarm target will only be known after getting off the highway and entering the general road. That is, there is also a drawback that the existence of the alarm target cannot be known near the exit on the highway.

[0070] On the other hand, as in the present embodiment, if an alarm is issued on the condition that the traveling distance to reach the alarm target candidate through the recommended route becomes equal to or less than the approach distance, as shown in FIG. 5, since the traveling distance from the vehicle G traveling on the general road to the alarm target candidate K3 on the highway is long, it is possible not to issue an alarm. Further, if a vehicle exists at the position of the alarm target candidate K3 (while traveling on the highway), although the linear distances from the vehicle position to the alarm target candidates K2 and K4 are very short, in order to actually reach the positions of the alarm target candidates K2 and K4, it is necessary to get off the highway at a distant interchange exit and then travel on the general road and return, and the traveling distance becomes very long. Therefore, the alarm target candidates K2 and K4 in such a case can also be excluded from the targets for which an alarm is issued. On the other hand, although specific illustration is omitted, when the vehicle is traveling near the exit of the highway, the traveling distance to the alarm target installed on the outermost road around the exit is relatively short because it is only necessary to get off at such an exit, and it can be set as an alarm target for which an alarm is issued. Therefore, by making a judgment based on the traveling distance to reach the alarm target candidate through the recommended route, usually, when traveling on a general road or a highway, it is possible not to issue an alarm for alarm targets on different road types, and it is possible to set as targets for which an alarm is issued for alarm targets existing on the general road near the highway exit from traveling on the highway or vice versa, for alarm targets near the entrance of the highway from traveling on the general road near the entrance of the highway.

[0071] Furthermore, in the case of the example described above, for all four alarm target candidates K1 to K4, the installation directions are registered (monitoring the directions of the arrows in the figure), so the control unit 18 determines whether or not condition 3 is satisfied. When the vehicle is traveling toward the installation direction, if it continues to move forward, it will enter the monitoring area of the alarm target and be monitored. As an example, when the alarm target is, for example, a vehicle speed measuring device, the traveling speed of the host vehicle is measured, and when the alarm target is the N system, the license plate of the host vehicle is photographed.

[0072] That is, as shown in Fig. 7(a), when the traveling direction of the vehicle and the installation direction (monitoring direction) of the warning target are opposite (the angle formed is 180 degrees), it can be determined that there is a warning target to be warned in front of the traveling direction of the vehicle, and it can be determined that entering the monitoring area of the warning target will occur if the vehicle proceeds as it is. On the other hand, as shown in Fig. 7(b), when the angle formed by the traveling direction of the vehicle and the installation direction (monitoring direction) of the monitoring target is 0 degrees, since the vehicle is traveling in the opposite direction to the warning target or even when traveling towards the warning target but the monitoring direction is different, it is determined that it is not a warning target for which a warning should be issued. Further, in the present embodiment, in the example shown in Fig. 7, when it is within the range of ± a predetermined angle (for example, ± 90 degrees) centered on 180 degrees, it is determined as a warning target for which a warning should be issued. Of course, the angle range is not limited to 90 degrees and can be arbitrarily set. The specific algorithm for determining whether the installation direction of this warning target and the traveling direction of the vehicle have a predetermined angular relationship can be realized using, for example, the technology disclosed in Japanese Patent Application Laid-Open No. 2002-228741 and the like.

[0073] And what is important in the present embodiment is how the relationship between the traveling direction of the vehicle traveling on the road where the warning target is finally installed and the monitoring direction of the warning target is. That is, for example, focusing on the warning target candidate K4, since the traveling direction of the current vehicle and the installation direction of the warning target candidate K4 are almost in the same direction, based on the traveling direction of the vehicle at the current position, it reaches the judgment result that it is not a warning target for which a warning should be issued. However, when actually reaching the warning target candidate K4 and passing in front of it, as shown by the route R4 in Fig. 6(d), it will travel towards the installation direction of the warning target, and it will become a warning target for which a warning should be issued.

[0074] Also, focusing on the warning target candidate K1, since the traveling direction of the current vehicle and the installation direction of the warning target candidate K1 are almost in the opposite direction, based on the traveling direction of the vehicle at the current position, it reaches the judgment result that it is a warning target for which a warning should be issued. However, when actually reaching the warning target candidate K1 and passing in front of it, as shown by the route R1 in Fig. 6(a), it will travel in the same direction as the installation direction of the warning target, and it will no longer be a warning target for which a warning should be issued.

[0075] As a result, in terms of the relationship between the traveling direction of the vehicle and the installation direction of the warning target, warning target candidates K2 and K4 become the targets for which warnings are issued, and warning target candidates K1 and K3 do not become the targets for which warnings are issued. Therefore, the control unit 18 extracts warning target candidates K2 and K4 as warning targets that satisfy condition 3.

[0076] Of course, in a conventional method disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-228741, etc., if approaching warning target candidate K4, a warning can be issued because the traveling direction of the vehicle and the installation direction of the warning target are opposite. However, in the present embodiment, a warning can be issued from a position farther away in advance. Also, in the above conventional method, warning target candidate K1 is once recognized as a target for which a warning should be issued and a warning is notified. As the vehicle moves forward, it deviates from a predetermined angular range in front based on the own vehicle position, so although a warning is not issued until the end, in the present embodiment, since no warning is issued from the beginning, it is possible to prevent unnecessary warnings and notifications from being given to the driver.

[0077] Furthermore, the control unit 18 notifies the warning target candidates K2 and K4, which are the targets for which warnings should be issued and are extracted in this way, using warning output means such as the display unit 5, the lamp 6, and the speaker 20. The notification in this case can be basically the same as that of a conventionally known one.

[0078] That is, FIG. 8 shows an example of a warning screen based on the example shown in FIG. 5. Here, two warning target candidates K2 and K4 are used as actual warning targets, and a predetermined polygon is drawn at the corresponding position on the map according to the warning types registered for them.

[0079] First, the layout of the screen area adopts a configuration in which a strip-shaped icon display area E2 is arranged above a rectangular main display area E1 that occupies most of it. Of course, this icon display area E2 may be provided at an appropriate position on the lower side or left and right, or may not be provided. The icon display area E2 includes icons indicating the operating state of the device, such as an icon I1 indicating that GPS is receiving, and an icon I2 for notifying the type of warning target. Such display is performed under the control of the control unit 18. Further, in the icon display area E2, the remaining distance to the warning target is drawn at its right end. In order to make this remaining distance prominent, it may be drawn in a separate window at an appropriate position such as the lower right in the main display area E1. In that case, the right end of such an icon display area E2 may be used to draw the current time, date, or other information. Also, this remaining distance may be a straight-line distance as in the conventional case, but preferably, it is the travel distance when passing through the recommended route from the current position to the warning target. By doing so, the numerical value of the remaining distance decreases (approaches), which matches the actual travel distance, so there is no sense of discomfort.

[0080] Also, the main display area E1 mainly shows the positional relationship between the warning target and the own vehicle, and is an area for displaying objects of predetermined shapes at their respective positions. This display unit 5 draws respective images and the like by dividing them into a plurality of layers. Specifically, the background color is drawn on the bottommost layer. This background color is drawn in a gradient so that it becomes brighter toward the front side (own vehicle side: lower side of the screen), or is drawn in a single color. Further, the color is made different according to the positional relationship with the warning target. That is, when the warning target exists but is separated by a certain distance or more (for example, 500 m or more), the base color is green, and when the distance to the warning target approaches less than a certain distance, the base color is changed to a different color (for example, "yellow"). Further, when approaching, the color is appropriately changed, such as using red as the base, so that the driver can easily understand that they are approaching.

[0081] This is the remaining distance to the warning target that serves as the criterion for changing the color. Conventionally, it may be based on the straight-line distance between the two, but preferably, it is the travel distance when passing through the recommended route from the current position to the warning target. By changing the color based on the travel distance, even if the straight-line distance is very close as if existing on an adjacent road, when the travel distance to reach the warning target candidate through the recommended route is far, by using a green base color, the driver can be made to understand that they will not arrive immediately.

[0082] The control unit 18 calls the map data corresponding to the displayed space and draws the map data (schematic road map) on the layer existing above the layer of the background color. Then, the control unit 18 draws various objects on the layer above the drawing layer of the map data. An object indicating the position of the own vehicle (hereinafter referred to as "own vehicle object") Gob is drawn at a predetermined position below the main display area R1. In the figure, it is drawn as a two-dimensional mark with an arrow indicating the traveling direction drawn inside a circle, but the own vehicle object Gob may be composed of a triangular pyramid or a quadrangular pyramid polygon to make it more three-dimensional. In that case, when the control unit 18 draws the own vehicle object Gob, the apex of the triangular pyramid or quadrangular pyramid should face forward in the traveling direction of the vehicle, and it should be drawn so as to appear floating in the air (draw a shadow downward). In the following description, even if there is no special notice, it is the control unit 18 that draws each object and other images on the display screen of the display unit 5.

[0083] Also, when there is an object to be alerted within the displayed space, the object to be alerted is drawn at the corresponding position on the screen. At this time, there are often multiple objects to be alerted registered in the database 19. In this case, one that meets the conditions is set as the actual object to be alerted (the target of the alert), and the alert target object Kob is drawn at the position on the display screen corresponding to the existence position of the alert target. For other objects that could be alert targets, the control unit 18 draws an object corresponding to the type of the detected alert target as a POI (Point Of Interest) object Iob at the corresponding position.

[0084] In the figure, both the alert target object Kob and the POI object Iob are two-dimensional marks with symbols indicating the type of the alert target inscribed in a circle. For the alert target object Kob, it is shown with a pair of triangular indication marks so that its existence can be clearly seen at a glance. Furthermore, for this alert target object Kob, when the installation direction is registered, that direction is also shown with an arrow. This allows the driver to immediately tell whether there is an alert target on the road where they plan to drive.

[0085] Also, the alert target object Kob and the POI object Iob may also be drawn as three-dimensional polygons similar to the own vehicle object. In that case, it is preferable for the display mode of the alert target object Kob to be a three-dimensional shape imitating something related to the actual alert target, as its type can be more intuitively understood.

[0086] Also, as a display mode of the alert, in order to make the existence of the alert target object Kob more noticeable, it is good to draw a "guide line" connecting the alert target object Kob from the own vehicle object Gob. This guide line has both ends in contact with or close to the own vehicle object Gob and the alert target object Kob, and is further drawn on the road of the path from the own vehicle object Gob to the alert target object Kob or along the side of that road.

[0087] In particular, when there are a large number of POI objects Iob, it may be difficult to immediately find the object to be alarmed among them. As shown in Fig. 8, simply adding a triangular indication mark or making it blink may make it difficult to distinguish from other POI objects Iob. Especially in the case of a radar detector, since the area of the display unit is smaller compared to a car navigation device, the lack of clarity becomes more prominent. Therefore, it is advisable to connect the two with a dotted line or a guide line consisting of a different color. Then, by following the guide line, the driver can easily find the object to be alarmed.

[0088] Also, in that case, as shown in Figs. 9(a) to (c) for example, an animation is created such that a guide line S in the form of a dotted line flows from the own vehicle object Gob to the object to be alarmed Kob, and finally the tip reaches the object to be alarmed Kob. By watching this animation, the driver can easily understand the presence of the object to be alarmed Kob. In addition, since the guide line S by the animation extends along the road, it can be easily understood whether it is the road the driver himself / herself is about to drive on, and it can be intuitively understood whether it is an object to be vigilant about or not related. [Other determination methods for the recommended route]

[0089] In the above-described embodiment, in process (2), when obtaining the recommended route that is the reference for obtaining the travel distance, the control unit 18 determines the recommended route by selecting one that satisfies conditions such as the shortest distance among a plurality of routes from the current position to the alarm target candidate. When obtaining this recommended route, it may be obtained by taking into account the installation direction used in condition 3. That is, a general recommended route selects the one with the shortest travel distance or the one that can be reached in a short time among several routes from the current location to the destination. However, as a condition for selecting the route, on a road where there is an alarm target candidate with an installation direction set, a route that proceeds in the direction of the installation direction as the direction approaching the alarm target is set as the recommended route.

[0090] And when obtaining the recommended route in this way, since the installation direction has already been taken into account, the determination of whether or not to issue an alarm to be performed in the above-described process (3) is made based on whether or not Condition 2 is satisfied. That is, the control unit 18 determines as an alarm target for which an alarm should be issued those for which the traveling distance until reaching the alarm target candidate through the recommended route is within a predetermined approach distance (for example, 2 km).

[0091] For example, as shown in FIG. 6(a), for the alarm target candidate K1, the recommended route is not the route coming from the right side but the route coming from the left side. That is, in FIG. 6(a), assuming that the route reaches the alarm target candidate by going around (clockwise) from the side opposite to the current traveling direction, the traveling distance is calculated. If the distance is 2 km or more, it is not set as an alarm target.

[0092] [Determine whether an alarm should be issued based on the number of right and left turns] In the above-described embodiments and modified examples, as an algorithm for determining whether or not to issue an alarm to be performed using road network information, the determination is made based on the traveling distance when traveling on the recommended route. However, the present invention is not limited to this, and various methods can be used. For example, there is one that performs the following (1), (2), and (3)'.

[0093] (1) First, the control unit 18 extracts alarm targets existing within a radius r (for example, 1 km, 2 km) from the vehicle position (current position) (Condition 1). This can be executed by the same algorithm as the extraction process of alarm targets existing around the current position based on the conventional straight-line distance, and the extracted alarm targets are set as alarm target candidates.

[0094] (2) Next, the control unit 18 executes a route search from the current position to each alarm target candidate. This is to sequentially set the position information of each alarm target candidate as the destination position information, and obtain the recommended route from the current position to the destination based on the road network information stored in the database 19. As a method for calculating this recommended route, for example, a known method such as Dijkstra's method can be used.

[0095] Details of the processing up to (1) and (2) are omitted as they are the same as those described above. Also, when obtaining the recommended route in this processing (2), the installation direction of condition 3 may be considered as in the above-described modification example for the determination.

[0096] (3)' Next, determine the number of intersections where a right or left turn is made when proceeding along the recommended route from the current position to the warning target candidate. A warning target candidate where the number of such intersections is n or more (the number of intersections passed straight through is not counted) is not considered a warning target for which a warning should be issued. In other words, a warning target candidate where the number of intersections is less than n is considered a warning target for which a warning is issued. That is, in a case where a complex route that does not reach the warning target without making a right or left turn at n or more intersections is traveled, it is highly likely that the road where the actual warning target is installed will not be passed. Particularly, even if the straight-line distance is short but a large number of turns at intersections are required to reach there, the possibility of not going to the location where such a warning target is installed is extremely high. Therefore, since there is a high possibility of issuing a useless warning to the driver by notifying such a warning target, it is not set as a warning target for which a warning is issued.

[0097] As a result, among the warning targets existing within a certain distance in terms of the straight-line distance, relatively easily reachable (high possibility of reaching) warning targets can be extracted and warned. In other words, by not warning those warning targets with a low actual possibility of reaching among the warning targets existing in the surroundings, the number of warning targets to be warned can be effectively reduced, and what is necessary for the driver can be appropriately notified. Of course, even if it is less than n times, when the installation direction of the warning target is set, a function may be provided to discriminate whether or not to be a warning target based on the angular relationship with the traveling direction of the previous road.

[0098] Also, when n is set to 2, it is preferable because it is possible to prevent an object to be warned, which is installed on another road parallel and close to the road on which the vehicle is traveling, from being a warning target for issuing a warning. That is, for example, as shown in FIG. 10(a), it is assumed that while the vehicle G is traveling on the left road, a warning target K is installed on the right road parallel thereto. In this case, if the vehicle continues straight on the left road, it will not reach the warning target K on the right road. Therefore, for a driver traveling straight on the current left road, the warning about the warning target K is useless and will be rather disturbing if issued.

[0099] As is clear from FIG. 10(a), in order for the vehicle G to travel along the recommended route and reach the warning target K, it is necessary to turn twice, such as turning right at the intersection A and then turning left at the intersection B. Without being limited to this example, when there are two substantially parallel (non-intersecting) roads, in order for a vehicle traveling on one road to reach the other road, at least the traveling direction needs to be changed (right turn / left turn) at an intersection on the traveling road in order to deviate from the traveling road, and further, in order to enter the other road, it is necessary to turn right or left at an intersection on the other road. Therefore, the driving route needs to be changed at least twice at intersections. On the other hand, when a warning target exists on a road intersecting the road on which the vehicle is traveling, such as the warning target candidate K2 illustrated in the above-described embodiment, there is a possibility of causing a situation of facing the warning target by simply turning once at an intersection on the traveling road.

[0100] Therefore, by setting n = 2, it is possible to know in advance the warning targets installed at the destination after turning at an intersection, etc., and the warning targets installed on other parallel roads, etc. do not need to be notified.

[0101] In addition, in the case shown in FIG. 10(a), as shown in FIG. 10(b), when turning right at the intersection A, the recommended route from the current position of the vehicle G at that time to the warning target K is to turn left once at the intersection B to reach the warning target K, so a warning will be issued at that point.

[0102] Also, as shown in Fig. 10(a), when driving on the left road and there is a warning target on the left road, even if the driving distance to such a warning target is longer than the driving distance to the warning target K installed on the right side, since it is necessary to turn twice to reach the warning target K, the control unit 18 will issue a warning about the warning target installed on the left road.

[0103] Also, regarding the way of giving a warning to the display unit, when there are a plurality of warning targets around, it is advisable to sort them in ascending order of the number of turns, and rank them so that those with fewer such turns have a higher priority. In addition, when the number of turns is the same, those with a shorter driving distance to the warning target have a higher priority. Of course, the priority can be further determined by taking into account the priority according to the type of the warning target.

[0104] [Judgment Based on Time] As another algorithm for determining whether a warning target should issue a warning, the predicted time until reaching the warning target may be used. That is, the control unit 18 obtains a recommended route by the methods shown in the above-described embodiments and modified examples. Then, the control unit 18 obtains the predicted time until reaching the warning target when driving on the obtained recommended route, and determines that it is a warning target for which a warning should be issued when the predicted time is equal to or less than a preset reference value. The predicted time may be calculated using, for example, probe information on traffic congestion status obtained by VICS or communication.

[0105] [Warning Mode for Display Unit] As shown in FIG. 11, for the warning targets existing around that satisfy Condition 2 or Condition 3, it is preferable to draw each warning information on the virtual dashboard 51 in a stacked manner in the front-rear direction as if having depth. The warning information described on the virtual dashboard 51 here is the type of warning target, the information for specifying the installation location, and the remaining distance, but it does not prevent other information from being displayed. And, for example, when driving on a straight road, imitating the scenery where the intersection guide boards installed at a plurality of intersections from the near side to the far side can be seen, the virtual dashboard 51 is drawn smaller toward the far side as if having depth. Thereby, the level of priority can be understood at a glance. Also, when the driving route changes as the vehicle moves forward, the priority order of each warning target also changes. In such a case, it is good to rearrange the front and rear of the virtual dashboard 51 according to the priority order.

[0106] Also, in the above-described embodiments and modified examples, those that do not satisfy the conditions are not drawn on the display unit 5 as warning targets that should not issue warnings, but the present invention is not limited to this, and the display mode may be changed for drawing. That is, those that do not satisfy the conditions should not become at least the warning target object Kob (the one that notifies detailed warning information). Furthermore, it is preferable that it does not become the content of the POI (Point Of Interest) object Iob either. And for the warning targets that satisfy Condition 1 and become warning target candidates but do not satisfy Conditions 2 and 3, a simple object (such as a simple form like a mere circle or reducing the radius of the circle) is drawn at the corresponding position. Thereby, the driver can know that it does not correspond to the warning target that should issue a warning, but there is some kind of warning.

[0107] In the above-described embodiments and modified examples, an example applied to a radar detector as an electronic device is shown, but the present invention is not limited to this, and it may be incorporated as a function of a car navigation device or other electronic devices.

[0108] Furthermore, in the above-described embodiments and modifications, the apparatus includes a database 19 that stores various types of information, and the control unit 18 accesses the database 19 to read necessary information and perform various processes. However, the present invention is not limited to this. That is, part or all of the information registered in the database 19 is registered in the server. Then, the radar detector and other electronic devices and apparatuses may be configured as a system that has a function of communicating with the server, and the control unit 18 appropriately accesses the server to acquire necessary information and execute processes.

Explanation of Reference Numerals

[0109] 1 Case body 2 Solar panel 4 Microwave receiver 5 Display unit 6 Lamp 7 Infrared communication device 8 GPS receiver 9 Adapter jack 10 Power switch 11 Mobile phone 12 Memory card reader 14 Memory card 15 Wireless receiver 16 Remote control receiver 17 Remote control 18 Control unit 19 Database 20 Speaker

Claims

1. A function for obtaining the current location of the vehicle; A function of displaying warning targets around the vehicle on a map; A function of displaying an arrow indicating the installation direction or monitoring direction of the alarm target on the map; Equipped A system characterized by:

2. A function of displaying on the map an arrow indicating the traveling direction of the vehicle when the vehicle reaches the alarm target in addition to the arrow indicating the installation direction or monitoring direction.

2. The system of claim 1 .

3. The arrow indicating the installation direction or monitoring direction and the arrow indicating the travel direction are displayed so as to be distinguishable from each other.

3. The system of claim 2.

4. a function of, when there are a plurality of warning targets, prioritizing the plurality of warning targets in the order of the number of turns the vehicle makes before reaching the warning target, and, when the number of turns is the same, in the order of the distance traveled by the vehicle before reaching the warning target; a function of displaying the plurality of alarm targets so that the priority order can be recognized; Equipped 4. A system according to claim 1, wherein the first and second inputs are connected to the first and second inputs.

5. A program for causing a computer to realize the functions of the system according to any one of claims 1 to 4.

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