Navigation apparatus

In a navigation apparatus having a cradle unit that is fastenable to a vehicle and is equipped with at least a microcomputer; and a front panel unit that is attachable to and detachable from the cradle unit and is equipped with at least a display displaying map data and a microcomputer performing a navigation function to indicate a determined location of the vehicle on the map data, it is configured such that a panel is integrally formed at bottom of the cradle unit to be attachable to the vehicle. With this, it becomes possible to provide the navigation apparatus configured such that a member having a microcomputer performing a navigation function is attachable/detachable to/from the main body, i.e., the base unit, thereby improving ease of use, that the member can be easily attached to the dashboard of the vehicle, and that unnatural impression is prevented from arising in the appearance.

TECHNICAL FIELD

This invention relates to a navigation apparatus, more specifically to an apparatus mounted in a vehicle for communicating to a driver information (directional, map, road, etc.) for reaching a destination.

BACKGROUND ART

Although navigation apparatuses of the foregoing type were initially limited to types integrally fixed to the vehicle, there have recently also been proposed easily-carried portable types, as well as detachable navigation apparatuses that further improve ease-of-use by enabling only the section with navigation functions to be mounted and dismounted (see, for example, Patent Reference 1).

According to the technology taught by Patent Reference 1, a navigation apparatus comprising a GPS receiver connected to a GPS antenna, a gyrosensor, a vehicle signal processor circuit including a vehicle speed signal, a display for displaying a map, and an ECU for overall control is equipped with a vehicle side unit provided on the vehicle side and a detachable unit detachably provided on the vehicle, and at least the gyrosensor and the vehicle signal processor circuit are mounted on the vehicle side, while the display and ECU are installed in the detachable unit to enable removal from the vehicle for use in the outside of the vehicle.Patent Reference 1: Japanese Patent No. 3376813

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

When the aforementioned navigation apparatus is attached to a dashboard of the vehicle, it is attached through a cradle unit. In this case, it is preferable to be able to easily attach the apparatus and prevent unnatural impression from arising in the appearance.

The object of this invention is therefore to solve the aforesaid drawbacks and provide a navigation apparatus that is configured such that a member having a microcomputer performing a navigation function is attachable/detachable to/from a main body, i.e., a cradle unit, thereby improving ease of use, that the member can be easily attached to a dashboard of a vehicle, and that unnatural impression is prevented from arising in the appearance.

Means for Solving the Problems

In order to achieve the object, as recited in claim1mentioned below, this invention is configured to have a navigation apparatus having: a cradle unit that is fastenable to a vehicle and is equipped with at least a microcomputer; and a front panel unit that is attachable to and detachable from the cradle unit and is equipped with at least a display displaying map data and a microcomputer performing a navigation function to indicate a determined location of the vehicle on the map data, characterized in that: a panel is integrally formed at bottom of the cradle unit to be attachable to the vehicle.

As recited in claim2mentioned below, the apparatus is configured such that the panel is formed with an extension part that is extended to vicinity of an external power supply socket when the panel is attached to the vehicle.

As recited in claim3mentioned below, the apparatus is configured such that back of the extension part is formed with a gap that houses an electrical wire extending from the external power supply socket to the cradle unit.

Effects of the Invention

In claim1, in a navigation apparatus having: a cradle unit that is fastenable to a vehicle and is equipped with at least a microcomputer; and a front panel unit that is attachable to and detachable from the cradle unit and is equipped with at least a display displaying map data and a microcomputer performing a navigation function to indicate a determined location of the vehicle on the map data, it is configured such that a panel is integrally formed at bottom of the cradle unit to be attachable to the vehicle. With this, it becomes possible to provide the navigation apparatus that is configured such that a member having a microcomputer performing a navigation function is attachable/detachable to/from the main body, i.e., the base unit, thereby improving ease of use, that the member can be easily attached to the dashboard of the vehicle, and that unnatural impression is prevented from arising in the appearance.

In claim2, in the apparatus, it is configured such that the panel is formed with an extension part that is extended to vicinity of an external power supply socket when the panel is attached to the vehicle. With this, in addition to the foregoing effects, connection with the external power supply becomes further easier.

In claim3, in the apparatus, it is configured such that back of the extension part is formed with a gap that houses an electrical wire extending from the external power supply socket to the cradle unit. With this, in addition to the foregoing effects, the electrical wire supplying power to the cradle unit can be made invisible and unnatural impression is prevented from arising in the appearance.

BEST MODES FOR CARRYING OUT THE INVENTION

Best modes for carrying out the navigation apparatus according to this invention are explained with reference to the attached drawings in the following.

First Embodiment

FIG. 1is a perspective view from the front of a base unit and front panel unit of a navigation apparatus according to a first embodiment of this invention,FIG. 2is perspective view from the rear of the front panel unit, andFIG. 3is perspective view of the front panel unit (rear side), a cradle unit and a cradle unit attachment arm.FIG. 4is an explanatory view showing it in the installed condition,FIG. 5(a) is an explanatory view from a vehicle driver's seat, andFIG. 5(b) is a side view thereof showing the vicinity of a steering wheel.

As illustrated, the navigation apparatus according to this embodiment of the invention is fastened to or built into (is fastenable to/in) the dashboard of a vehicle A, and is equipped with the base unit10supplied with operating power from a power supply (battery) of the vehicle A, the cradle unit12to be fastened (fastenable) on the dashboard of a vehicle B and supplied with operating power from a power supply (battery) of the vehicle B, and the front panel unit14attachable/detachable to/from the base unit10or cradle unit12. The vehicle A and vehicle B are automobiles.

The navigation apparatus according to this embodiment is basically the combination of the base unit10and front panel unit14. However, an application in which the front panel unit14is attached to the cradle unit12is also acceptable. As shown inFIG. 4, the advantages of this apparatus can be enhanced if base units10-1,10-2,10-3. . . or cradle units12-1,12-2,12-3. . . are removably installed in associated vehicles A1, A2, A3. . . or B1, B2, B3. . . , and the user uses the apparatus after presetting the front panel unit14to his or her personal screen settings and switching it to correspond to the ID number of the associated base unit10or cradle unit12.

The base unit10is equipped with a base unit case10ahaving the overall shape of a box and internally accommodates a board or the like on which is mounted, inter alia, a microcomputer enabling operation of audio equipment of the vehicle A. The front of the base unit case10ais formed to 2DIN (DIN: Deutsches Institut für Normung) size and has a recess10bformed therein.

The front panel unit14is equipped with a plate-shaped front panel unit case14aabout the same size as or somewhat larger than the front of the base unit10and the front of the front panel unit case14ais equipped with a liquid crystal panel (display)14bfor displaying map data and switches provided to be operable by the user (operator), including, for example, a destination input switch14cand a current location input switch14d. The liquid crystal panel14bis provided with a touch panel capable of detecting points touched by the user (operator), as will explained later. Symbols14eand14fdesignate jacks for connecting an iPod (registered trademark) and analog audio equipment, respectively.

The front panel unit14is configured to be detachably mounted in a recessed part10a1and a recess10bof the front of the base unit case10a(to be freely attached and detached). Of the operations of the attach/detach mechanism, the mounting will be explained first. As shown inFIG. 2, the back of the front panel unit14is formed on the left side with two vertically spaced fixed claws14gand on the right side with two vertically spaced movable catch slides14h. Two vertically spaced movable lock levers10care provided on the right side of the recess10bof the base unit10, and two vertically spaced fixed claws10dare formed on the left side, and when the front panel unit14is attached, they respectively engage with the fixed claws14gand catch slides14hof the front panel unit14.

Note that in this specification the “vertical” direction is that on the vertical axis (gravitational axis) of the base unit10, front panel unit14and the like in their condition as fastened to the vehicle A or B and the lateral direction is a direction perpendicular thereto.

As shown inFIG. 1, a connector10eis provided in the recess10bof the base unit10. When attached to the base unit10, the front panel unit14is supplied with operating power from the power supply (battery) of the vehicle A through the connector10eand sent/received with data and control signals of various sensors, including a GPS signal receiver20, AV equipment and the like therethrough. Among the electrical contacts of the connector10e, the left and right electrical contacts are ground contacts.

The recess10bof the base unit10is provided alongside the connector10eat the bottom with multiple ground terminals10p, specifically two designated10p1and10p2, made of a conductor such as copper.

Turning next to an explanation of the detachment, a detach button14iis provided on the front panel unit14under the jacks14eand14f. When the front panel unit14is in the attached state with the base unit10and the user presses the detach button14i, the resulting movement is transmitted to the lock levers10cthrough a detach knob10fprovided in the base unit10, whereby the lock levers10care moved outward to disengage them from the fixed claws.

The catch slides14hon the right side of the front panel unit14are only urged outward (rightward inFIG. 2) by spring force to be engaged with the fixed claws10dof the base unit10. Therefore, if the engagement between the lock levers10cand the fixed claws14gon the left side is released and the user moves the front panel unit14(leftward inFIG. 1) by greater than the overlap span of the catch slides14hand the fixed claws10d, the engagement with the base unit10is released to enable detachment of the front panel unit14from the base unit10.

As shown inFIG. 1, a release lever10gis provided in the recess10bin the front of the base unit10. When the front panel unit14is attached, the release lever10gis urged in the direction of ejecting it by a kick lever loaded with a spring (neither shown). A panel unit detection switch (not shown) is attached to the release lever10gand produces outputs or signals in response to the location of the release lever10g, i.e., the attachment and detachment of the front panel unit14; for example, produces an ON signal when the front panel unit14is attached and an OFF signal when it is detached.

As shown inFIGS. 2 and 3, the cradle unit12is detachably attached to the back of the front panel unit14. The attach/detach mechanism between the front panel unit14and cradle unit12is not illustrated, but it is similar to the attach/detach mechanism between the front panel unit14and base unit10explained with reference toFIG. 1, and the front panel unit14is removably attached to the cradle unit12via lock levers, catch slides and so on. The cradle unit12is also equipped with a panel unit detection switch.

The cradle unit12is fastened to the dashboard of the vehicle B through a cradle unit attachment arm16. The cradle unit12is equipped with a cradle unit case12athat is shorter in height and greater (deeper) in depth than the front panel unit case14aand internally accommodates, inter alia, a board on which a microcomputer and the like are mounted.

The front panel unit14is fastened to the dashboard of the vehicle B also through a panel integrated cradle, other than a set of the cradle unit12and cradle unit attachment arm16. This will be explained later.

As shownFIG. 5, the front panel unit14of the navigation apparatus according to this embodiment is either mounted near the driver's seat of the vehicle A or B, more exactly is installed in the base unit10(not visible inFIG. 5) built into the dashboard D, or installed on the dashboard D via the cradle unit12. In either location, the front panel unit14is installed at a height near that of a windshield18.

More concretely, when the front panel unit14is attached to the base unit10, the longitudinal center line14bcof the liquid crystal panel of the front panel unit14is, as viewed by the user (of average sitting height), slightly higher than the rotation center SWc of the steering wheel SW and considerably higher than the rotation center SHc of the steering shaft at the dashboard plane (substantially the front plane of the front panel unit14), i.e., the rotation center SHc is located toward the undersurface of the front panel unit14. Symbol SL designates a transmission shift lever.

As set out in the forgoing, the front panel unit14of the navigation apparatus according to this embodiment is configured to be attachable/detachable to/from the base unit10or cradle unit12.

FIG. 6is a block diagram showing the internal configuration of the front panel unit14and base unit10, andFIG. 7is a block diagram showing the internal configuration of the front panel unit14and cradle unit12.

As shown inFIG. 6, the front panel unit14is equipped with a microcomputer (called the “navigation microcomputer”)14mand the base unit10is equipped with a microcomputer (called the “system microcomputer”)10i. Further, as shown inFIG. 7, the cradle unit12is equipped with a microcomputer (called the “cradle microcomputer”)12b. The navigation microcomputer14mhas several times greater processing capability than the system microcomputer10iand cradle microcomputer12b.

Continuing the explanation ofFIG. 6, the base unit10equipped with the system microcomputer10iis further equipped with a traffic information module (VICS)10kfor receiving traffic information via an antenna10jattached to the vehicle A, a tuner10lfor receiving broadcast waves sent to onboard audio equipment (AM/FM radio etc.; not shown) of the vehicle A, an audio circuit block10mfor controlling the operation of the onboard audio equipment, a video circuit block10nfor displaying DVD and other images on the liquid crystal panel14bof the front panel unit14, a DVD module10ofor operating in intercommunication with the system microcomputer10i, reading audio and image signals from a CD or DVD, demodulating the image signals and sending them to the video circuit block10nas analog signals, a TV tuner10qfor receiving terrestrial digital broadcasts via an antenna10p, and an EEPROM10rcomprising a nonvolatile memory.

The base unit10is further equipped with a GPS signal receiver (designated “GPS”)20for receiving GPS (Global Positioning System) signals, a wheel speed sensor (designated “SPEED PLS”)22, a gyrosensor (designated “GYRO”)24and a reverse gear switch (designated REVERSE)26. The reverse gear switch26is connected to a transmission or a transmission shift lever30(FIG. 5).

The GPS signal receiver20is equipped with an antenna20awhich is attached at an appropriate location such as on the base unit case10a, dashboard or meter visor. Note that when the front panel unit14is detached from the base unit10and attached to the cradle unit12, the GPS signal receiver20uses an antenna attached at an appropriate location on the cradle unit case12aor attachment arm16.

The wheel speed sensor22is installed near the driveshaft (not shown) of the vehicle A and outputs a pulse signal every predetermined rotation angle of the driveshaft, i.e., wheels (tires) (in other words, it detects the rotational speed of the vehicle A wheels). The gyrosensor24is disposed inside the base unit case10aand produces an output whose voltage varies with the angular velocity (yaw rate) about the gravity axis (vertical axis) at the center of gravity of the vehicle A (in other words, it detects the angular velocity (yaw rate) about the vertical axis, more specifically about the three axes X, Y and Z).

The gyrosensor24is enabled to experience the same vibration as the vehicle A by installing it on a suitable board in the interior of the base unit case10ato be near edge or other board attachment screws, and since its sensitivity varies with attachment angle, the attachment angle is measured after attachment to the vehicle A and the measured value is stored in the EEPROM10ras a correction value.

The reverse gear switch26installed at an appropriate location on the transmission (not shown) or shift lever30(shown inFIG. 5) of the vehicle A and outputs an ON signal when the reverse gear for backing up the vehicle A is engaged (ON) or the shift lever30is in the R position, i.e., when the vehicle A is about to back up.

The front panel unit14equipped with the navigation microcomputer14mis further equipped with a RAM14n, a FLASH memory14ofor storing map data and the like for navigation, a BT (Bluetooth) module14qfor transmitting and receiving 2.45 GHz radio waves to/from a mobile telephone hands-free microphone via an antenna14pattached to the front panel unit case14a, a memory card14r, a touch panel14sinstalled on the liquid crystal panel14b, a touch panel microcomputer14tfor controlling the operation thereof, a timing controller14ufor generating various sync signals for liquid crystal display, a video switch14vfor performing input/output of the video circuit block10nand the like of the base unit10, and a wireless module14xfor wireless reception of image data from a rear camera in the same frequency band via an antenna14wattached to the front panel unit case14a.

To be more specific, the BT module (short-range transceiver module)14qand wireless module (dedicated image data receiving module)14xare installed on the back of the front panel unit case14a.

In the configuration shown inFIG. 6, the signal receiver20that receives the GPS signals is installed on the base unit10, and the location information acquired from the GPS signals is, along with the outputs of the wheel speed sensor22, gyrosensor24and reverse gear switch26, sorted into time-coincident data, integrated and sent to the navigation microcomputer14mby the system microcomputer10i.

After first acquiring the location of the vehicle A based on the GPS signals, the navigation microcomputer14mcorrects it based on the outputs of the wheel speed sensor22and the gyrosensor24. Thus, the navigation microcomputer14mdetermines the location of the vehicle A by autonomous navigation. The vehicle location determined by autonomous navigation is stored in the FLASH memory14oand/or the EEPROM10rat regular intervals, so that the current location can be estimated immediately after the engine of the vehicle A is started and power is turned ON.

Note that low-speed digital signals are sent and received between the system microcomputer10iand the navigation microcomputer14mover a signal line (serial data line), while image signals inputted through the TV tuner10qare sent out to the front panel unit14over a separate data line as high-speed digital signals. In contrast, image signals inputted from the DVD module or exterior are inputted to the video circuit block10nof the base unit10and thereafter sent over a signal line to the video switch14vof the front panel unit14as analog signals. The video switch14vsends its output to the navigation microcomputer14mas a digital signal and also receives a control signal inputted from the navigation microcomputer14m. In addition, the picture signal of the wireless module14xis sent through the video switch14vto the video circuit block10nfrom where it can be sent through an external terminal to another video device for viewing, recording or the like.

Next, turning to an explanation of the internal structure of the cradle unit12with reference toFIG. 7, the cradle unit12equipped with the cradle microcomputer12bis further equipped with an audio circuit block12cfor controlling audio input to a speaker built into the cradle unit12, an FM transmitter12efor radio wave transmission of the output of an audio module from an antenna12d, an EEPROM12fcomprising a nonvolatile memory, and a TV tuner12hfor receiving terrestrial digital broadcasts via an antenna12g.

Note that when the front panel unit14is detached from the base unit10and attached to the cradle unit12as set out above, the antenna20aof the GPS signal receiver20used is that of the vehicle B.

The cradle microcomputer12bsends the location information obtained from the GPS signals to the navigation microcomputer14mof the front panel unit14and the navigation microcomputer14mdetermines the location of the vehicle B based solely on the GPS signals.

As regards the navigation microcomputer14mand system microcomputer10ishown inFIG. 6, the software configuration of the navigation microcomputer14mis shown inFIG. 8and the software configuration of the system microcomputer10iis shown inFIG. 9.

In the case of operating equipment that, like a navigation apparatus, has many functions and many settings, use of a Graphical User Interface (hereinafter called “GUI”) enables the user to visually understand the operating method. Taking this point into account, the navigation apparatus according to this embodiment incorporates into the navigation microcomputer14mof the front panel unit14shown inFIG. 6a configuration enabling GUI customization, whereby the functions are executed through the user's operation of the touch panel14s.

Specifically, as shown inFIG. 8, the navigation microcomputer14mis equipped with a GUI function for displaying a menu on the liquid crystal panel14band executing functions designated by having the user touch specified sites on the touch panel14s, a function (application functions) for executing operations selected by the GUI function, a function (platform functions) for defining processing times for various functions and managing memory space, and a function (driver) for accessing individual peripheral devices (hardware). The GUI function comprises an XML parser14m1, a VIEW controller14m2and a MODEL controller14m3.

As mentioned earlier, the navigation microcomputer14msupplies tuner and disk drive control commands to the system microcomputer10iof the base unit10over the signal line (serial data line).

As shown in S1to S8of the flowchart inFIG. 9, on the base unit10side, the system microcomputer10ireceives commands from the navigation microcomputer14m, controls peripheral devices, and conveys the information obtained from the devices and sensor data to the navigation microcomputer14mover the serial data line. Although not shown in the drawings, in the cradle unit12the cradle microcomputer12bperforms similar processing to the system microcomputer10i.

In addition, in the front panel unit14, the navigation microcomputer14mdetermines based on the sensor output condition whether the outputs of the three sensors or just the GPS signals of one sensor output should be used as the sensor(s) for determining the location of the vehicle.

FIG. 10is a flowchart showing this processing.

Now to explain, in S10it is checked whether attachment to the base unit10of the front panel unit14in which it itself is accommodated was detected. Since communication with the system microcomputer10ithrough the signal line becomes possible upon attachment to the base unit10, the navigation microcomputer14mthereby judges whether its own attachment to the base unit10was detected.

When the result in S10is YES, the program goes to S12, in which the output (pulse signal) of the wheel speed sensor22is inputted for X seconds (predetermined time period), e.g., 3 seconds, and the program goes to S14, in which it is checked whether the pulse signal is being produced.

When the result in S14is YES, the program goes to S16, in which self-location estimation is done in three-sensor mode, i.e., (vehicle A) self-location is determined from the outputs of three sensors (GPS signal receiver20, wheel speed sensor22and the gyrosensor), and when the result in S14is NO, the program goes to S18, in which self-location estimation is done in single-sensor mode, i.e., (vehicle A) self-location is determined from the output (GPS signals) of the GPS signal receiver20.

For example, during driving on a congested road, the output of the wheel speed sensor22is sometimes not produced or becomes sporadic, but making the decision based on sensor output condition enables the sensor(s) used for location determination to be optimally selected to enhance the accuracy of vehicle location determination, while the flexibility of sensor use in location determination is improved in the point that the location determination is not necessarily restricted to use of three sensors.

Note that although in the processing ofFIG. 10the output of the wheel speed sensor22is checked by inputting it for X seconds, it is possible instead to check whether the output of the wheel speed sensor22exceeds a predetermined threshold value and select the single-sensor mode when it does not.

Moreover, in the front panel unit14, in addition to conducting the processing ofFIG. 10, the navigation microcomputer14mrecognizes from the information from the system microcomputer10ior the cradle microcomputer12bwhich is installed and determines whether self-location determination should be conducted using the outputs of the three sensors or just the GPS signals of one sensor output. Specifically, the navigation microcomputer14mof the front panel unit14determines the sensor(s) (detector(s)) to be used for determining the location of the vehicle in accordance with the attached/detached condition of the front panel unit14. The base unit10and cradle unit12are assigned respective ID numbers (identification numbers) that are stored in the nonvolatile EEPROMs10rand12f.

FIG. 11is a flowchart showing this processing, which, as in the case ofFIG. 10, is executed by the navigation microcomputer14m.

Now to explain, in S20it is checked whether attachment of the front panel unit14in which it itself is accommodated was detected. Since communication with the system microcomputer10ior the cradle microcomputer12bthrough the signal line becomes possible upon attachment, the navigation microcomputer14mthereby judges whether its own attachment in the base unit10was detected.

When the result in S20is YES, the program goes to S22, in which the ID number (identification number) of the attachment mate (mounting mate) is read, to S24, in which it is checked whether the attachment was on the base unit10, and when the result is YES, to S26, in which self-location estimation is done in three-sensor mode, i.e., (vehicle A) self-location is determined from the outputs of three sensors (GPS signal receiver20, wheel speed sensor22and the gyrosensor).

When the result in S24is NO, it means that the attachment was on the cradle unit12, so the program goes to S28, in which self-location estimation is done in single-sensor mode, i.e., (vehicle B) self-location is determined from the output (GPS signals) of the GPS signal receiver20.

Thus, a configuration is adopted that determines the sensor(s) to be used in determining the location of the vehicle A or B in accordance with the attached/detached condition of the front panel unit14, thereby making it possible to improve the flexibility of sensor use in location determination.

Next, the storage of the vehicle location will be explained.

As set out in the foregoing, multiple base units, e.g., base units10-1,10-2,10-3. . . , are sometimes provided, but in such a case, it is possible that the location data of the vehicle A stored in the nonvolatile memory (FLASH memory14o) in the front panel unit14is data of another vehicle, i.e., of the vehicle A2, A3or the like. As a result, cases arises in which there is no choice but to confirm by receiving GPS signals and determining the location after mounting.

Therefore, in the navigation apparatus according to this embodiment, when multiple base units10are provided, the location information immediately before removal and the ID number are together stored in the EEPROM (nonvolatile memory)10rof the base unit10, as shown at the left ofFIG. 12. On the other hand, as shown at the right ofFIG. 12, when the front panel unit14is detached from the base unit10, the ID number of the base unit and the location data are stored as a pair, and when the front panel unit14is attached to the same base unit again, the location information at the time of detachment is read from that ID number and used as the location information. This makes it possible to prevent use of wrong location information.

Further, irrespective whether there is a single or multiple base units10, if the front panel unit14should be detached and attached again after the vehicle A has moved, cases may arise in which the current location and the location information stored in the front panel unit14differ.

Therefore, in conducting the processing in the navigation apparatus according to this embodiment, a flag FLV indicating that the vehicle A moved while the front panel unit14was detached is included in the EEPROM10rof the base unit10.

FIG. 13is a flowchart showing this processing. The illustrated processing is executed by the system microcomputer10i.

Now to explain, in S100, it is checked whether the front panel unit14was detached. This is judged from the output of the panel detection switch. When the result in S100is YES, the program goes to S102, in which the bit of the flag FLV is set to 1, and to S104, in which it is checked whether the vehicle has moved. This is judged from the output of the wheel speed sensor22.

When the result in S104is NO, the program goes to S106, in which it is checked whether the front panel unit14was attached again, and when the result is NO, returns to S104. On the other hand, when the result in S104is YES, the program goes to S108, in which the bit of the flag FLV is reset to 0. Note that when the result in S104is NO and the result in the ensuing S106is YES, S108is skipped because, at any rate, the vehicle has not moved.

FIG. 14is a flowchart showing the processing executed by the navigation microcomputer14mresponsive to the processing ofFIG. 13.

Now to explain, in S200, whether or not attached to the base unit10is continuously checked based on the output of the panel detection switch, and when the result is YES, the program goes to S202, in which the flag FLV stored in the EEPROM10rof the base unit10is read, and to S204, in which it is checked whether the bit of the flag FLV is set to 1.

When the result in S204is YES, it means that the vehicle has not moved, so the program goes to S206, in which it is checked whether the ID number of the base unit10concerned is in a history table (shown inFIG. 12), and when the result is YES, to S208, in which the location information paired with the ID number concerned is adopted as the subject vehicle location.

On the other hand, when the result in S204is NO, the program goes to S210, in which the location information stored in the base unit10is read. The same applies when the result in S206is NO. Next, in S212, it is checked whether the read information is not 0 data, and when the result is YES, the program goes to S214, in which the read information is adopted as the subject vehicle location, and when it is NO, the program goes to S216, in which current location setting is conducted (described later).

Specifically, after the front panel unit14is detached, the system microcomputer10iof the base unit10writes the location information contained in the GPS signals and the mounted vehicle orientation information to the EEPROM10revery time the power is turned OFF. When GPS location determination is not complete at this time, it writes 0 data.

In the front panel unit14, when, after the installation in the base unit10, the navigation microcomputer14mdetermines by referring to the flag FLV that the location information stored therein is unusable, it reads the location information stored in the base unit10and, provided that it is not 0 data, adopts it as the subject vehicle location (S204, S210, S212, and S214). Therefore, even when the once-detached front panel unit14is reattached after the vehicle has moved, it can nevertheless function as a navigation apparatus that indicates the subject vehicle location.

However, in even such a case, it will be impossible at some locations, such as in an underground parking lot, to acquire GPS signals upon attachment of the front panel unit14, leaving no choice other than to adopt 0 data for the subject vehicle location. When the subject vehicle location is lost, it is impossible to calculate a route to the destination or to predict the arrival time or the like.

So, in the navigation apparatus according to this embodiment, it is made possible in the case where the subject vehicle location was lost, and only in such case, to set the subject vehicle location in the same manner as setting a destination (S216). Specifically, the user is allowed to define the subject vehicle location by selecting it from address search results or nearby landmark information, thereby enabling destination setting, route calculation and the like.

After this, the user cannot be offered guidance until GPS signals are received and the location is determined while driving on a road, but once GPS signals are picked up, that location can be used as the subject vehicle location to guide the user by autonomous navigation.

Next, navigation information storage and information sharing between base units will be explained.

In a navigation apparatus, the practice in determining self-location is to use vehicle-specific parameters. Namely, since the sensitivity of the gyrosensor24varies with attachment condition, the angle at the time of attachment is measured and stored in memory and sensor output is corrected using the stored value during navigation.

In the autonomous navigation, the calculation of traveled distance uses the distance traveled during one pulse output by the wheel speed sensor22(Distance Per Pulse). This DPP is calculated from the traveled trajectory derived from the GPS signals and the number of wheel speed sensor22pulses and is constantly updated.

Since the attachment angle of the gyrosensor24and the traveled distance DPP are parameters specific to the vehicle in which the navigation apparatus is installed, this embodiment stores these parameters in the EEPROM10rof the base unit10. In this arrangement, if the user replaces only the base unit10with a new one, such information must be once saved to a memory card or the like and then copied to the new base unit10.

Taking this point into account, the navigation apparatus according to this embodiment once saves the information (parameters) stored in the EEPROM10rof the base unit10to the front panel unit14side and copies it to the new base unit10in accordance with the instructions of the navigation microcomputer14m. As a result, the information can be shared when the base unit is replaced.

Next, explanation will be made regarding interference between wireless modules and the like, i.e., the device priority and the like.

In the navigation apparatus according to this embodiment, since the front panel unit14is equipped with two wireless modules, i.e., the BT module14qand the wireless module14x, interference is liable to occur between the two. For example, when the vehicle is backing up (when rear camera images are being displayed), if a DVD playback request is made or the mobile telephone with hands-free microphone receives a call, device operations may interfere. Note that, although the main function is receiving signals, the wireless module14xis also capable of transmission and, in addition, conducts mutual confirmation processing and communication quality confirmation processing.

So, priority is established and the devices are operated accordingly.FIG. 15is an explanatory diagram of this processing. In this diagram, events, i.e., operations of the reverse gear switch26, mobile telephone with hands-free microphone and the DVD, are represented on the horizontal axis, and associated states, i.e., vehicle backing up, phone engaged, and DVD playing, are represented on the vertical axis.

FIG. 16is a flowchart showing processing executed by the navigation microcomputer14mbased onFIG. 15.

Turning to an explanation in line withFIG. 16made with reference toFIG. 15, first, in S300, it is checked whether the reverse gear switch26is outputting an ON signal, i.e. whether the vehicle is about to back up, and when the result is NO, the program goes to S302, in which the operation of the rear camera (Wireless Camera) is stopped, the WLC (Wireless Camera) wireless function is turned OFF, and the video from the rear camera is terminated.

Next, in S304, it is checked whether the mobile phone is engaged (ringing), and when the result NO, the program goes to S306, in which the ringer function of the hands-free system is turned OFF and the function of the BT module14qis turned OFF (i.e., put in standby mode).

Next, in S308, it is checked whether the DVD is playing, and when the result is NO, the program goes to S310, in which it is checked whether the playback button (on the touch panel14s) is pressed, and when the result is YES, goes to S312, in which DVD playback is started and DVD video is displayed on the liquid crystal panel14b. This is because the vehicle is not about to back up, so rear camera images are unnecessary.

On the other hand, when the result in S300is YES, the program goes to S314, in which mobile telephone call acceptance (ringing) is cut off and the BT module14qis shut off because it is also unnecessary (i.e., wireless signal send/receive is discontinued; note that power shutdown is acceptable as the means for this). Next, in S316, DVD playback is stopped and DVD display is turned OFF, whereafter the program goes to S318, in which the rear camera is activated, the WLC function is turned ON and rear camera images are displayed, upon which the program returns to S300.

Further, when the result in S304is YES, the program goes to S320, in which the ringer tone is transmitted through the onboard speaker and the BT module14qfor audio send/receive is turned ON (i.e., is activated). Next, in S322, it is checked whether the disconnect button (on the touch panel14s) is pressed, and when the result is YES, the program goes to S324, in which the ringer tone is turned OFF and the BT module14qis turned OFF because it is unnecessary. Note that when the result in S322is NO, S324is skipped.

Further, when the result in S308is YES, the program goes to S326, in which it is checked whether the stop button (on the touch panel14s) is pressed, and when the result is YES, it goes to S328, in which DVD playback is stopped and the DVD display is turned OFF. Note that when the result in S326is NO, S328is skipped.

Owing to the processing shown inFIGS. 15 and 16, display of the rear camera images taken rearward of the vehicle A is ensured, so that the user can back up while watching them. Further, device operation does not interfere.

Next, the FM transmitter12eof the cradle unit12will be explained.

The FM transmitter12ein the cradle unit12shown inFIG. 7is a means that operates using the navigation microcomputer14mto transmit the music contents or voice guidance in the memory card14rof the front panel unit14over the onboard speaker. However, the output level of radio wave transmitters is regulated by the radio laws and regulations of individual countries, which makes transmission at weak power inevitable. Therefore, when driving near a radio station, noise occurs owing to the effect of its radio waves.

Therefore, in the navigation apparatus according to this embodiment, a database of local radio station frequencies is stored in the EEPROM12fof the cradle unit12, and the cradle microcomputer12bfinds a vacant frequency for the respective travel segments, or for the entire travel route to the destination, and displays the frequency on the liquid crystal panel14bof the front panel unit14.

If the user tunes the frequency of the car receiver (car audio) thereto, music contents or voice guidance can be outputted from the onboard speaker for listening. This makes it possible to offer the user the music contents or voice guidance with minimal noise. The cradle microcomputer12boutputs the music contents and voice guidance through the FM transmitter12eto output it from the onboard speaker.

Note that while the FM transmitter installed in the cradle unit12in this embodiment, it is also acceptable to provide it in the base unit10.

Next, the GUI shown inFIG. 8will be explained further.

As was explained regardingFIG. 8, in the case of operating equipment that, like a navigation apparatus, has many functions and many settings, use of the GUI enables the user to visually understand the operating method, and therefore, the navigation apparatus according to this embodiment incorporates into the navigation microcomputer14mof the front panel unit14shown inFIG. 6a configuration enabling GUI customization, whereby the functions are executed through the user's operation of the touch panel14s.

The configuration of the GUI (functions) ofFIG. 8is shown inFIG. 17. Turning once again to the explanation of the GUI, the parser14m1defines the screen configuration, specifically it defines the button locations, button file names, button names and the like, and detects button touches. The VIEW controller14m2defines the menu configuration, i.e., it determines which skin to display when a button is pressed. The MODEL controller14m3sends the selected function message to the application layer. The application layer executes commands sent from the GUI.

While configuring in the manner shown inFIG. 17enables the user to visually understand the operating method, the number of menus increases with increasing number of functions, with the result that the menu hierarchy becomes deeper. Therefore, in order to execute a function, the user has to select menu buttons many times to select a desired function, which is rather liable to be more complicated. From the user's viewpoint, more narrowed down functions may be easier to use.

The menu screen is composed of skin files defining screen configurations prepared for the individual screens (background file name, button display location, button file name, button name and the like) and the messages issued when the individual buttons are selected, and bitmap files prepared for the individual constituent elements (menu buttons) of the menu screens called from skin files. These skin files and bitmap files are stored in the nonvolatile memory (FLASH memory)14o, and the navigation microcomputer14mdisplays them on the liquid crystal panel14butilizing the XML parser function.

The XML parser14m1sends a message to the VIEW controller14m2in response to a user operation. The VIEW controller14m2examines the message contents, switches the displayed skin file, and, if necessary, sends a command request to the MODEL controller14m3. The MODEL controller14m3checks the requested command and sends an operation command to the application layer. In this structure, switching the skin file changes the menu screen. The skin files are written in XML or other such language.

When customizing the GUI, the practice is to compile skins and controllers in a menu configuration composed of all original functions, then compile skin files without the keys desired to be deleted from the menu screen and thereafter replace the skin files concerned. This makes it possible to disable the display of menus and issuance of application commands at and below the deleted buttons and to delete their functions. An example thereof is shown inFIG. 18(deleted portions are indicated in broken lines).

Further, when the skin files are written in a language such as XML, the button layout and button shapes can be modified simply by changing the skin file description. Adopting this method makes customization possible simply by replacing the skin files, without need to rewrite the program.

The original skin files are loaded into nonvolatile memory and the skin files desired to be changed are put in the memory card14ror the like. The user puts the desired skin files in the memory card14r, and after turning on the power, replaces skins by selecting files in the memory card14rusing the initial settings skin select menu. In this case, however, the user must select the preferred skin(s) at every power-on, so that setting becomes necessary every time the vehicle engine is turned off. Conversely, if the skins are fixed, only a particular user can benefit from the skin change.

The navigation apparatus according to this embodiment is configured so that each of the front panel unit14, base unit10and cradle unit12includes a nonvolatile memory and a microcomputer, and the memories store unique ID numbers by which they authenticate one another at the attachment process. In other words, the respective microcomputers can each identify the other at the time of attachment. Further, since the base unit10and cradle unit12are fastened to the vehicle, the front panel unit14can also identify the vehicle on which it itself is attached based on the ID number.

In view of the recent tendency for each person to own his or her own car and for every car to have one particular user, a situation is likely to arise in which the base unit10or the cradle unit12is installed in every car and only a single front panel unit14is kept on hand for shared use. So skin file names are in advance defined in the single front panel unit14in correspondence to the ID numbers of the base units10and cradle units12in which attachment is expected, the ID number of the mate is read at mounting, and changeover of the skin files in the memory card14ris done automatically.

FIGS. 19 and 20are flowcharts showing this processing. The processing shown is executed by the navigation microcomputer14m.

The processing shown inFIG. 19is premised on multiple types of skin files being stored in the memory card14rof the navigation microcomputer14mof the front panel unit14, and is executed in response to operation by the individual users of multiple vehicles when the front panel unit14is attached to the base unit10or cradle unit12.

Now to explain, in S400, the user is prompted to select one of the multiple types of skin files stored in the memory card14r, whereafter the program goes to S402, in which the selected skin file is read and displayed on the liquid crystal panel14b. Next, the program goes to S404, in which it is checked whether the user pressed the skin file setting OK button, thereby confirming whether the user accepts the setting, and when the result is NO, the program returns to S400.

On the other hand, when the result is YES in S404, the program goes to S406, in which the ID number of the mate, i.e. of the base unit10or cradle unit12of the vehicle owned by the user who initiated the operation, is inputted, and the inputted ID number and name of the selected skin file are registered (stored) in the nonvolatile (FLASH) memory14oof the front panel unit14.

Note that in this case registration (storage) in the EEPROM10rin the base unit10or the EEPROM12fin the cradle unit12, or in a separately provided nonvolatile memory, is also applicable.

Moreover, it is also possible to enhance the reliability of the apparatus by, in addition to providing the front panel unit14with the separate nonvolatile memory, also providing the base unit10or cradle unit12with a nonvolatile memory, registering (storing) the ID number of the mate, the selected skin file, the name thereof and the like in both nonvolatile memories, and when one set of data cannot be used or is not correct, using the data on the side that is not abnormal, and when both are abnormal or their data are different, preferentially using the data of the nonvolatile memory of the front panel unit14.

The processing shown inFIG. 20is executed when, following completion of the processing shown inFIG. 19, the detached front panel unit14is attached to the base unit10or cradle unit12.

Now to explain, in S410, the fact of the front panel unit14having been attached to the base unit10or cradle unit12is confirmed, whereafter the program goes to S412, in which the ID number of the mate (the base unit10or cradle unit12) in which the front panel unit is attached is read, and to S414, in which it is checked whether a skin file with a name associated with the read ID number is registered. When the result in S414is NO, the remaining processing step is skipped, and when it is YES, the program goes to S416, in which the skin file with the selected name stored in the memory card14ris adopted as the skin file for display, more exactly, is automatically selected.

This allows automatic switching of the skin file by the user to match the vehicle upon mounting. Since, however, it is of course possible to imagine a case in which every car does not have its own particular user, the menu is always provided with a button for switching to the original menu.

Although the GUI change procedure presumes user selection from among a number of GUIs prepared beforehand, it is also conceivable for users themselves to customize the GUI. In such case, the menu organization procedure will involve selection of a button not in use, so that there is a risk of inadvertently deleting a required button.

Therefore, this embodiment is configured so that each button is assigned a non-erasable attribute in the button delete procedure, and the attribute is unfailingly checked in the delete-button selection step, thereby making it impossible to delete buttons that must not be deleted. Further, frequently used and functionally indispensable buttons known to be undeletable from the start are assigned hard keys so they will not be displayed during menu editing.

FIG. 21shows examples of buttons that must not be deleted (undeletable buttons).FIG. 22is a flowchart of the foregoing.

Now to explain, all menu buttons are displayed in S500and the program goes to S502in which the user is asked to select a button to be deleted. The program then goes to S504, in which it is checked whether the selected button can be deleted, and when the result is YES, to S506, in which the selected button is deleted. Note that when the result in S504is NO, the processing of S506is skipped.

Next, the program goes to S508, in which it is checked whether the button editing is finished, and when the result is NO, the program returns to S502, and when it is YES, the program is terminated. To be more specific, after the processing for each button deletion is completed, the message “Quit button editing?” is displayed along with YES and NO buttons, and when the NO button is pressed by the user, the result in S508is NO and the program returns S502, and when the YES button is pressed, the result in S508is YES and the program closes.

Owing to the foregoing configuration, the operation becomes easy for the user because the use of the GUI gives the user a visual understanding of the operation method, and user operation can be made still easier by narrowing down the menu buttons as required. Further, even when users customize the GUI on their own, they do not end up inadvertently deleting necessary buttons.

Next, explanation will be made regarding the installation site of the TV tuner10q.

When TV viewing functions are incorporated in the navigation apparatus, use needs to be restricted. In the case where the TV viewing functions are all centralized in the front panel unit14, the practice would be to send the output of the wheel speed sensor22for discriminating whether the vehicle is actually driving from the base unit10to the navigation microcomputer14mand for the navigation microcomputer14mto use it to turn the TV viewing functions ON and OFF.

However, in such a configuration, if the signal line (serial data line) interconnecting the base unit10and front panel unit14should be hacked and a pseudo signal sent to the front panel unit14, the turned-off TV viewing function would be turned on.

In the navigation apparatus according to this embodiment, should the TV tuner10qbe installed in the front panel unit14, the image signal received by the vehicle outside antenna would routed through the base unit10to the front panel unit14. In this case, it would not be possible to obtain an image signal of good quality because the broadcast waves acquired from the antenna, being high in frequency and weak, are easily affected by the impedance of the path and ambient noise. In particular, owing to the connection of the front panel unit14and the base unit10through the connector10e, the image signal is affected also by occurrence of contact loss.

Further, if a TV antenna should be installed directly on the front panel unit14in the condition being attached to the base unit10, the size of the front panel unit which is determined based on the base unit size is decreased by a portion of the antenna, so that the size of the liquid crystal panel (display)14bwould have to be reduced.

Taking these points into consideration, the TV tuner10qof the navigation apparatus in accordance with this embodiment is installed in the base unit10as shown inFIG. 6. Specifically, since the system microcomputer10iof the base unit10receives the output of the wheel speed sensor22, whether the vehicle is driving can be easily determined, the operation of the TV tuner10qcan be restricted when driving is found to be in progress.

In other words, since the determination of whether the vehicle is driving and the restriction of TV tuner10qoperation are completed inside the base unit10, it becomes difficult to disable the TV view restriction by hacking from the outside.

Further, the effect of path impedance and noise can be mitigated to enhance picture quality by transferring the image signal to the front panel unit14after converting it to a digital signal in the TV tuner10q.

Next, explanation will be made regarding theft of the front panel unit14.

The front panel unit14is detachable from the base unit10and therefore susceptible to theft. Therefore, in this embodiment, theft of the front panel unit14is deterred by registering in the EEPROM10rof the base unit10or the EEPROM12fof the cradle unit12their ID numbers (identification numbers) and checking whether they agree therewith, specifically, by making the front panel unit14which has not been registered in advance inoperable.

FIG. 23is a flowchart of this processing showing processing executed by the navigation microcomputer14m.

Now to explain, in S600, it is checked whether attachment of the front panel unit14in which it itself is accommodated was detected. Since communication with the system microcomputer10ior the cradle microcomputer12bthrough the signal line becomes possible upon attachment, the navigation microcomputer14mthereby judges whether its own attachment was detected.

Next, the program goes to S602, in which the ID number (identification number) of the attachment mate (mounting mate) is read, to S604, in which it is checked whether it coincides with the ID number registered in advance, skips the remaining processing step when the result is YES, and when it is NO, goes to S606, in which it sounds a warning. Note that simultaneously with or instead of this, current location information is automatically notified to a previously designated telephone number through the BT module14q.

While the microcomputer (navigation microcomputer)14mdoes the processing ofFIG. 23discussed above, the navigation microcomputer14malso executes various other processing such as the processing shownFIG. 10. And the system microcomputer10iof the base unit10executes processing such as that shown inFIG. 13. The same is true of the cradle microcomputer12bof the cradle unit12.

The processing by these microcomputers will explained hereinafter with reference toFIGS. 24 to 26.

FIG. 24is a flowchart showing a main routine for conducting the aforesaid processing by these microcomputers, namely, the navigation microcomputer14m, system microcomputer10iand cradle microcomputer12b, e.g., the processing (hereinafter called “processing task”) shown inFIG. 10etc. conducted by the navigation microcomputer14m.

The illustrated routine starts when the ignition key is turned ON to supply operating power from the vehicle A (or vehicle B) power supply (battery), whereupon initialization is executed first (S700) and the prioritization of 1 to n processing tasks is set in a predetermined RAM area (S702).

Next, the OS (operating system) is activated (S704), all processing tasks are initialized (S706), and standby mode is entered in a task selection step (S708). In this standby mode, when an event flag is set by an interrupt explained later, the event corresponding to the set event flag (one of S710to S71n) is executed. When the processing of the corresponding event is finished, the routine returns to the task selection processing (S708), in which the standby mode is maintained until an event flag is set by the next interrupt.

Specifically, in the task selection step (S708), whether or not an event flag has been set is monitored through the interrupt processing (explained later), and when setting is detected, the processing task corresponding to the set event flag is executed. Note that when interrupts conflict, processing tasks are executed in accordance with the priority set in S702. The processing from initialization (S706) to event (one of S710to S71n) corresponds to OS processing.

FIG. 25is a flowchart showing the aforesaid interrupt processing routine andFIG. 26is a block diagram showing the hardware configuration of the microcomputers used for the interrupt processing.

Broadly divided, the interrupt processing consists of a hardware-based processing portion independently processed with no relationship to software later loaded into the microcomputer and an interrupt processing routine portion that is software loaded into the individual microcomputers, and when data or a trigger signal is inputted to an interrupt terminal (A to n) ofFIG. 26, or a trigger signal is produced in a counter that orders interrupts at predetermined time intervals, the aforesaid hardware-based processing is commenced in the microcomputer, and the contents of the different registers containing the data that is currently in use for or has been processed by OS processing are transferred to respective stack areas (1 to n).

Then, after the current value of the program counter has been transferred to the stack area, the value written to the interrupt address (A to n) corresponding to the interrupt terminal to which the data or the like was inputted is written into the program counter. Owing to this rewriting of the program counter value, the program currently being processed is suspended (held) and the interrupt processing routine ofFIG. 25is launched.

In the interrupt processing routine ofFIG. 25, first the interrupt processing routine (S800) is launched, next the flag of the event flag corresponding to the terminal etc. that received the interrupt is set (S802), and finally an interrupt processing routine termination command is issued (S804), thereby terminating the interrupt processing routine.

Upon issuance and execution of this interrupt processing routine termination command, the hardware-based processing is restarted in the microcomputer and the values transcribed to the stack areas (1 to n) at the time of suspension are written back to the original registers, whereafter the program counter value temporarily saved at the time of suspension is rewritten to the program counter from the stack area, thereby terminating the interrupt processing sequence and restoring the state immediately before the interrupt. From this point onward, the suspended (held) program being executed up to immediately before the interrupt is executed again.

Next, the antennas will be explained.

As can be seen fromFIGS. 6 and 7, the navigation apparatus according to this embodiment has numerous antennas. Aside from the navigation apparatus, the vehicle is equipped with an FM/AM radio, which also has an antenna. Although it is possible to install the antennas independently, this embodiment uses a unitary film antenna200, as shown inFIG. 27.

The output of the film antenna200is amplified by a broadband high-frequency amplifier202, whereafter it is divided by a divider204and forwarded through a connector206for input to the base unit10(or front panel unit14or cradle unit12). The symbol208designates a power line. The film antenna200is stuck on one among, for example, the windshield18, rear window, roof outer surface, rearview mirror or the like of the vehicle.

Otherwise, as shown inFIG. 28, it is possible to internally install the high-frequency amplifier202for each antenna200and send the outputs to the base unit10through the connector206and divider204. In this case, no high-frequency amplifier202needs to be connected to the FM/AM radio antenna because its wavelength is relatively long.

Otherwise, as shown inFIG. 29, it is possible to provide multiple film antennas200, stick them on different ones of the windshield18, rear window, roof outer surface, rearview mirror or the like, and use the divider204of the base unit10or the like to select the one with higher electric field strength.

As set out in the foregoing, this embodiment is configured to have a navigation apparatus having: a base unit10that is fastenable to a vehicle and is equipped with at least a microcomputer (system microcomputer10i); and a front panel unit14that is attachable to and detachable from the base unit10and is equipped with at least a liquid crystal panel (display)14bdisplaying map data and a microcomputer (navigation microcomputer14m) performing a navigation function to indicate a determined location of the vehicle on the map data, characterized in that: there are provided with at least three sensors (detectors) including a receiver20that receives a GPS signal, a wheel speed sensor22that detects rotational speed of a wheel of the vehicle and a gyrosensor24that detects angular velocity about a vertical axis of the vehicle; and the microcomputer of the front panel unit14determines the detector or detectors to be used for determining the location of the vehicle in accordance with output condition of the detector or detectors (S10to S18). With this, the sensor(s) used for location determination can be optimally selected to enhance the accuracy of vehicle location determination, while the flexibility of sensor use in location determination can be improved in the point that the location determination is not necessarily restricted to use of the three sensors.

Further, and similarly, ease of use as a navigation apparatus can be improved by the adoption of the detachable format enabling the front panel unit14to be detached from the base unit10and mounted in another vehicle or to be taken home for input of destinations, routes and the like.

Further, it is configured to have a navigation apparatus having: a base unit10that is fastenable to a vehicle and is equipped with at least a microcomputer (system microcomputer10i); and a front panel unit14that is attachable to and detachable from the base unit and is equipped with at least a liquid crystal panel (display)14bdisplaying map data and a microcomputer (navigation microcomputer14m) performing a navigation function to indicate a determined location of the vehicle on the map data, characterized in that: there are provided with at least three sensors (detectors) including a receiver20that receives a GPS signal, a wheel speed sensor22that detects rotational speed of a wheel of the vehicle and a gyrosensor24that detects angular velocity about a vertical axis of the vehicle; and the microcomputer of the front panel unit14determines the detector or detectors to be used for determining the location of the vehicle in accordance with attached/detached condition of the front panel unit14(S20to S28). With this, the flexibility of sensor use in location determination can be improved.

Further, and similarly, ease of use as a navigation apparatus can be improved by the adoption of the detachable format enabling the front panel unit14to be detached from the base unit10and mounted in another vehicle or to be taken home for input of destinations, routes and the like.

Further, the apparatus further includes: a cradle unit12that is fastenable to the vehicle and is equipped with at least a microcomputer (cradle microcomputer) and a receiver20receiving a GPS signal, wherein the front panel unit14is attachable to and detachable from the cradle unit12; and the microcomputer of the front panel unit14determines the location of the vehicle using outputs of the three sensors (detectors) when the front panel unit14is attached to the base unit10(S24, S26), and determines the location of the vehicle using only the GPS signal when the front panel unit14is attached to the cradle unit12(S24, S28). With this, in addition to the foregoing effects, the cradle unit12that is attachable/detachable with the front panel unit14and determines location using GPS signals is provided, thereby further enhancing ease of use as a navigation apparatus.

Note that the gyrosensor24is required for location determination in the three-sensor mode. Should the gyrosensor24be built into the front panel unit14, the sensitivity might change and accuracy decline owing to looseness of front panel unit attachment or inclination resulting from tilt adjustment of the front panel unit14. Size reduction of the front panel unit14itself might also be affected. In addition, if the output of the wheel speed sensor should be transferred to the front panel unit14, the number of contact terminals between the front panel unit14and base unit10would increase.

As a countermeasure, it would be possible to build the gyrosensor24into the base unit10and transfer the gyro data and the output of the wheel speed sensor22to the navigation microcomputer14mthrough the serial communication line after reading them in with the system microcomputer10iin the base unit10. However, in this case the routing through the system microcomputer10iwould give rise to a delay in information transfer to the navigation microcomputer14mand shift the timing relative to the GPS data acquisition.

The data of the three sensors is inherently location information, distance traveled information and direction information at each timing and must be simultaneously acquired and processed. Discrepancy in acquisition times affects location accuracy.

However, the navigation apparatus according to this embodiment is configured to install also the GPS signal receiver20on the base unit10side and so that the location information obtained from the GPS is, along with the gyro data and the output of the wheel speed sensor22, also sent to the navigation microcomputer14mafter being sorted and integrated by the system microcomputer10i, whereby the delay caused by data transfer through the system microcomputer10iis the same for all of the data of the three sensors, so that no such inconvenience occurs.

Note that also in this configuration, if the CPU processing capacity of the system microcomputer10iis high, the self-location estimation and/or navigation functions can also be conducted on the system microcomputer10iside. However, in order to display the display map data compiled by the system microcomputer10ion the liquid crystal panel14bof the front panel unit14, the image data compiled by the system microcomputer10iwould either be sent to the navigation microcomputer14mwithout modification and converted to an image signal for display by the navigation microcomputer14mor be converted to an analog image signal by the system microcomputer10iand transferred to the front panel unit14, to be displayed on the liquid crystal panel14b.

Since the map data is sent as color image data of one to five images per second, the data transfer volume is large. If transfer over a parallel bus should be attempted, the data lines (signal lines) between the front panel unit14and base unit10would increase considerably.

Further, in the case of transfer over serial data lines, the data signal lines would be monopolized by the map data transfer owing to the great map data transfer volume, so that the transfer of other information to be transferred from the system microcomputer10ito the navigation microcomputer14mwould become slow.

Further, in the case of moving the navigation functions from the navigation microcomputer14mto the system microcomputer10i, while it would be possible to lower the CPU capacity of the navigation microcomputer14m, microcomputers with processing capability on a level enabling navigation would have to be incorporated as the system microcomputer10iand cradle microcomputer12b, which would increase the system upgrade cost. Moreover, some users are likely to buy more than one cradle unit12, so that concentrating highly intelligent functions in the front panel unit14will lower their total costs.

In consideration of the foregoing, this embodiment is configured to complete navigation functions in the navigation microcomputer14mof the front panel unit14and use the system microcomputer10iof the base unit10to conduct peripheral equipment control.

Note that even in the case where the GPS signal receiver20is connected to the front panel unit14, the gyrosensor24is installed in the base unit10and the wheel speed sensor22is connected to the base unit10, the different signal data can be synchronized by the methods set out below.

1. The system microcomputer10iintegrates the outputs of the gyrosensor24and wheel speed sensor22and sends them to the navigation microcomputer14mtogether with timestamp data. The navigation microcomputer14malso stores the GPS data to memory paired with GPS data acquisition time timestamp data and conducts self-location estimation by combining data of the same time as the timestamp received from the system microcomputer10i.

2. A system that maintains fixed intervals among the time of wheel speed sensor22and gyrosensor24output acquisition by the system microcomputer10i, the time of transfer of these data to the navigation microcomputer14m, and the time of transfer of the GPS data from the GPS signal receiver20to the navigation microcomputer14m, are designed, and the different sensor signal acquisition times in the navigation microcomputer14mare managed and synchronized.

Further, as explained in the foregoing, this embodiment is configured to have a navigation apparatus having: a base unit10that is fastenable to a vehicle and is equipped with at least a microcomputer (system microcomputer10i); and a front panel unit14that is attachable to and detachable from the base unit and is equipped with at least a liquid crystal panel (display)14bdisplaying map data and a microcomputer (navigation microcomputer14m) performing a navigation function to indicate a determined location of the vehicle on the map data, characterized in that: the location of the vehicle is determined by using at least one of three sensors (detectors) including a receiver20that receives a GPS signal, a wheel speed sensor22that detects rotational speed of a wheel of the vehicle and a gyrosensor24that detects angular velocity about a vertical axis of the vehicle; and a short-range transceiver module (BT module)14qincluding an antenna14, and a dedicated image data receiving module (wireless module)14xare installed on the front panel unit, i.e., on the back thereof.

Since the dedicated image data receiving module (wireless module)14xis thus installed in the front panel unit14which is also installed with the navigation microcomputer14moperating the liquid crystal panel14bin this manner, images can be displayed without time lag.

The frequency band of the wireless module, such as the wireless module14x, in the reception status is 2.4 G except for a first short period during which the mutual confirmation processing and communication quality confirmation processing are conducted with the other party of communication. The rear camera images of the vehicle are transmitted by using 60% to 80% of the usable bandwidth in the above band and ensuring communication speed of 5 to 6 Mbps, so as to assure the necessary image quality level and high-speed communication, and in the case of the front camera, its images are transmitted by using 25% to 35%, i.e., ⅓ of the bandwidth, such that the respective communications of the rear camera and front camera are both become available for actual use simultaneously.

Further, while making the communication speed of the rear camera greater than that of the front camera, 10% to 15%, i.e., 1/10 of the band of the BT (Bluetooth) communication is remained for the BT communication, thereby ensuring stable high-speed communication, as minimizing the mutual interference.

As described with respect to the processing ofFIG. 16, when the rear camera is used, it is preferable not to utilize the BT communication of the BT module14qpositioned near the wireless module14xat the back of the front panel unit14to prevent noise induced by communication delay from occurring in the wireless module14x.

Further, when the front camera images are received by using the wireless module14x, the images may be stored in the FLASH memory14o, as being displayed in the liquid crystal panel of the front panel unit14, for checking the driving condition or persons and vehicles (including motorcycles and bicycles) passing in front of the subject vehicle, after driving.

Since memory capacity is limited for retaining records for a long period, in the cases where recording is conducted for a predetermined period before and after light-on and light-off of a head lump, winker or the like, where one to several (about 30) image(s) is automatically recorded at regular intervals (every 0.2 to 1 second) like a picture taken by a still camera when detecting a person (his/her face) or a vehicle (its license number, characteristic shape) through a software, and where 70% of the capacity of the FLASH memory14ois occupied, data may be transferred to an external record medium over a mobile phone line at every preset time period and all or at least 50% or more of the data recorded in the FLASH memory14omay be deleted.

Further, if it is within a communication range of a communication device connected to the front camera or rear camera of the vehicle, it becomes possible to monitor a parking space from the inside of a house and record it by removing the front panel unit14from the vehicle and attach it to the cradle unit12installed in the house.

In addition, the dedicated short-range transceiver module (BT module)14qincluding the antenna14pis installed on the front panel unit14, more specifically, on the back thereof, so that communication with the mobile telephone hands-free microphone in the vehicle is facilitated.

Further, as explained in the foregoing, the embodiment is configured to have a navigation apparatus having: a base unit10that is fastenable to a vehicle and is equipped with at least a microcomputer (system microcomputer10i); and a front panel unit14that is attachable to and detachable from the base unit and is equipped with at least a liquid crystal panel (display)14bdisplaying map data and a microcomputer (navigation microcomputer14m) performing a navigation function to indicate a determined location of the vehicle on the map data, characterized in that: the location of the vehicle is determined by using at least one of three sensors (detectors) including a receiver20that receives a GPS signal, a wheel speed sensor22that detects rotational speed of a wheel of the vehicle and a gyrosensor24that detects angular velocity about a vertical axis of the vehicle; the microcomputer (system microcomputer10i) of the base unit retains the location of the vehicle A even after the front panel unit14is detached from the base unit10; and the microcomputer (navigation microcomputer14m) of the front panel unit14determines the location of the vehicle based on driving condition of the vehicle (S200to S216ofFIG. 14).

In addition to the foregoing effects, this makes it possible by using the stored data to immediately determine location even when the front panel unit14is detached, insofar as the vehicle is not driving, while use of incorrect location data can be prevented because it is possible to avoid using the stored data when the vehicle has moved.

Further, as explained in the foregoing, the embodiment is configured to have a navigation apparatus having: a base unit10that is fastenable to a vehicle and is equipped with at least a microcomputer (system microcomputer10i); and a front panel unit14that is attachable to and detachable from the base unit and is equipped with at least a liquid crystal panel (display)14bdisplaying map data and a microcomputer (navigation microcomputer14m) performing a navigation function to indicate a determined location of the vehicle on the map data, characterized in that: the location of the vehicle is determined by using at least one of three sensors (detectors) including a receiver20that receives a GPS signal, a wheel speed sensor22that detects rotational speed of a wheel of the vehicle and a gyrosensor24that detects angular velocity about a vertical axis of the vehicle; a control program of the microcomputer (navigation microcomputer14m) of the front panel unit is configured to include a graphical user interface (GUI) function that is provided with a liquid crystal panel displaying a menu and a touch panel overlaid thereon on the liquid crystal panel14bto be pressed by a user to execute a specified function, an application function that executes the operation selected through the graphical user interface function, and a platform function that defines at least processing times for the functions; and an undeletable button is displayed on the touch panel (FIG. 21, S500to S508ofFIG. 22).

This facilitates user operation by giving the user a visual understanding of the operation method and simplifies user operation even further by making it possible to narrow down the menu buttons as required. Further, even when users customize the GUI on their own, they do not end up inadvertently deleting necessary buttons. In addition, modification in accordance with the vehicle model is also facilitated.

Further, as explained in the foregoing, the embodiment is configured to have a navigation apparatus having: a base unit10that is fastenable to a vehicle and is equipped with at least a microcomputer (system microcomputer10i); and a front panel unit14that is attachable to and detachable from the base unit and is equipped with at least a liquid crystal panel (display)14bdisplaying map data and a microcomputer (navigation microcomputer14m) performing a navigation function to indicate a determined location of the vehicle on the map data, characterized in that: the location of the vehicle is determined by using at least one of three sensors (detectors) including a receiver20that receives a GPS signal, a wheel speed sensor22that detects rotational speed of a wheel of the vehicle and a gyrosensor24that detects angular velocity about a vertical axis of the vehicle; and a tuner (TV tuner10q) that receives a TV image is provided in the base unit10such that an output (TV image signal) of the tuner is transferred from the microcomputer of the base unit to the front panel unit.

Since the system microcomputer10iof the base unit10thus receives the output of the wheel speed sensor22, it becomes possible to easily determine whether the vehicle is driving, and restrict the operation of the TV tuner10qwhen driving is found to be in progress. Moreover, since the determination of whether the vehicle is driving and the restriction of TV tuner10qoperation are completed inside the base unit10, it can make difficult to disable the TV view restriction by hacking from the outside.

Further, the effect of path impedance and noise can be mitigated to enhance picture quality by transferring the image signal to the front panel unit14after converting it to a digital signal in the TV tuner10q, thereby making it possible to improve picture quality.

Further, as explained in the foregoing, the embodiment is configured to have a navigation apparatus having: a base unit10that is fastenable to a vehicle and is equipped with at least a microcomputer (system microcomputer10i); and a front panel unit14that is attachable to and detachable from the base unit and is equipped with at least a liquid crystal panel (display)14bdisplaying map data and a microcomputer (navigation microcomputer14m) performing a navigation function to indicate a determined location of the vehicle on the map data, characterized in that: the location of the vehicle is determined by using at least one of three sensors (detectors) including a receiver20that receives a GPS signal, a wheel speed sensor22that detects rotational speed of a wheel of the vehicle and a gyrosensor24that detects angular velocity about a vertical axis of the vehicle, and characterized by: an FM transmitter12e; and means (EEPROM12f) for storing a database of frequencies of local radio stations in a region where the vehicle is traveling, wherein a vacant frequency for the region where the vehicle is traveling is searched and the searched frequency is displayed on the liquid crystal panel14bof the front panel unit14.

More specifically, the navigation apparatus includes a cradle unit12that is attachable to or detachable from the front panel unit and is equipped with at least a microcomputer (cradle microcomputer12b), wherein the FM transmitter12eis installed in the cradle unit12; and the microcomputer (cradle microcomputer12b) of the cradle unit12searches a vacant frequency for a region where the vehicle is traveling and displays the searched frequency on the liquid crystal panel14bof the front panel unit14.

As a result, by tuning the receiver to the frequency, the user can listen to music contents and voice guidance outputted from the onboard speaker and can listen to the music contents and voice guidance in a low-noise condition.

Here, the aforementioned dashboard panel integrated cradle (assigned by symbol32) will be explained.

FIG. 30is a perspective view of the dashboard panel integrated cradle (hereinafter called as “panel integrated cradle”)32,FIG. 31is a perspective view of the rear side thereof, andFIGS. 32 and 33are front views of the main portion thereof.FIG. 34is an explanatory view showing the condition where the panel integrated cradle32is attached to the vehicle.

As shown inFIG. 30, the panel integrated cradle32comprises a cradle case part32aaccommodating a cradle unit that has the same function as the cradle unit12shown inFIG. 3, and a panel32bformed at the bottom of the cradle case part32aintegrally therewith.

As shown inFIGS. 30 and 32, the front side of the cradle case part32ahaving the structure similar to the front of the base unit10, is formed with a recess32a1that is attachable/detachable with the front panel unit14(not shown). Symbol32a2designates a connector similar to the connector10e of the recess10bof the base unit10, and symbol32a3an add-on module. Symbol32a4designates ground terminals, specifically two designated32a41and32a42, similar to the ground terminals10p.

As shown inFIGS. 31 and 33, a recess32a5at the rear of the cradle case part32ais installed with a board32a6on which the cradle microcomputer12bis mounted.

The panel32bis formed with first, second and third notches32b1,32b2and32b3to exhibit ladder shape as viewed from the front and, as shown inFIG. 34, composed of a horizontal part parallel with the upper surface of the dashboard, a vertical part parallel with or along the elevation surface of the dashboard, as viewed from the side, and a curving part connecting the horizontal part and vertical part.

The panel integrated cradle32is attached to the dashboard of the vehicle B with adhesive tape32c. As described above, the front panel unit14is attached/detached to/from the recess32a1of the cradle case part32a.

FIG. 34is an explanatory view showing the condition where the panel integrated cradle32is attached to the dashboard of the vehicle B.

As illustrated, the first notch32b1is installed with a duct34of an air conditioner, the second notch32b2with an on-vehicle radio36and inside-outside air switching lever38, and the third notch32b3with a duct changeover switch40, air conditioner airflow dial42, and air temperature control switch44.

Owing to this configuration, airflow from the duct34is not interrupted and manipulation of the radio36, etc., by the user is not disturbed because the panel integrated cradle32does not block them.

An external power supply socket (cigarette lighter)50and ashtray52are installed at the lower portion of the duct changeover switch40. The panel32bof the panel integrated cradle32is extended at the bottom to form an extension part32b4. The extension part32b4is extended to the vicinity of the socket50.

As shown inFIG. 31, on the back of the panel integrated cradle32, a side portion including the extension part32b4, precisely the side portion (right side inFIG. 31) extending to the vicinity of the socket50, is formed with a gap or groove32b5, so that an electrical wire54(indicated by a dashed-line inFIG. 34) is able to be installed therein. The electrical wire54interconnects the socket50and the cradle unit accommodated in the cradle case part32ato enable power supply from the vehicle B to the cradle unit.

The ground side of the electrical wire54is connected to the ground terminals32a4, connector32a2and add-on module32a3shown inFIG. 32, and also to grounds of electronic devices connected to the cradle32and that of the board32a6(shown inFIG. 31) mounting the cradle microcomputer12b.

InFIG. 34, symbol56designates a steering wheel, symbol58meters and symbol60a meter visor. As illustrated, the panel integrated cradle32is positioned at a height near the meters58.

As set out in the foregoing, this embodiment is configured to have a navigation apparatus having: a cradle unit12that is fastenable to a vehicle B and is equipped with at least a microcomputer; and a front panel unit14that is attachable to and detachable from the cradle unit12and is equipped with at least a display14bdisplaying map data and a microcomputer (navigation microcomputer14m) performing a navigation function to indicate a determined location of the vehicle on the map data, characterized in that: a panel32bis integrally formed at the bottom of the cradle unit, more specifically, the panel integrated cradle32accommodating the cradle unit is formed, to be attachable to the vehicle B.

With this, it becomes possible to provide the navigation apparatus that is configured such that a member having a microcomputer performing a navigation function is attachable/detachable to/from the main body, i.e., the base unit10, thereby improving ease of use, that the member can be easily attached to the dashboard of the vehicle B, and that unnatural impression is prevented from arising in the appearance.

Further, the embodiment is configured such that the panel (32b) is formed with an extension part32b4that is extended to vicinity of an external power supply socket50when the panel is attached to the vehicle B. With this, in addition to the foregoing effects, connection with the external power supply becomes further easier.

Further, the embodiment is configured such that back of the extension part32b4is formed with a gap32b5that houses an electrical wire54extending from the external power supply socket50to the cradle unit. With this, in addition to the foregoing effects, the electrical wire54supplying power to the cradle unit can be made invisible and unnatural impression is prevented from arising in the appearance.

Further, since the panel integrated cradle32has ladder shape along the dashboard of the vehicle B as viewed from the front and L-shape as viewed from the side, it can be surely held on the dashboard regardless of vibration and turn of the vehicle B.

Further, since the panel integrated cradle32is installed near the duct34through the first notch32b1and it amounts to installment near the cooling air, the temperature increase can be suppressed.

Further, since the panel integrated cradle32is positioned at a height near the meters58, the user can see the liquid crystal panel14bof the front panel unit14without greatly shifting directions of his/her eyes.

Second Embodiment

FIG. 35is a flowchart similar to the flowchart ofFIG. 10, showing a navigation apparatus according to a second embodiment of the present invention. The illustrated processing is, like that ofFIG. 10, also executed by the navigation microcomputer14m.

Now to explain, the illustrated processing commences when the user operates a sensor mode switch screen suitably displayed on the touch panel14slocated on the liquid crystal panel14b, i.e., when the touch panel14sis pressed, whereupon, in S900, the sensor mode switch screen is displayed in response to the touch panel operation and the user is prompted to make a selection.

Next, the program goes to S902, in which it is checked whether the user selected the single-sensor mode, i.e., whether an instruction was inputted from the outside regarding the detector to be used for determining the location of the vehicle A, and when the result is YES, the program goes to S904, in which it is determined that self-location estimation is to be done in the single-sensor mode, i.e., that the self-location (vehicle A) is to be determined by the output (GPS signal) of the GPS signal receiver20, and when it is NO, to S906, in which it is determined that self-location estimation is to be done in the three-sensor mode, i.e., that self-location (vehicle A) is to be determined by the outputs of the three sensors (GPS signal receiver20, wheel speed sensor22and gyrosensor), i.e., the detector or detectors to be used for determining the location of the vehicle A are determined in accordance with an instruction from the outside.

Note that when the three-sensor mode or single-sensor mode has been determined by the navigation microcomputer14min the flowchart ofFIG. 10or the flowchart ofFIG. 11of the first embodiment, the processing ofFIG. 35is given priority.

To explain this point, there may arise circumstances that the user can readily discern, or that only the user can detect, such as that the tires were changed to tires of a different diameter, e.g., snow tires, or that the road surface condition changed considerably, e.g., when an ordinary road surface changed to a slippery, icy road surface. The same is true when the vehicle itself is new and the navigation microcomputer14m(or system microcomputer10i) has not yet finished learning the output of the wheel speed sensor22adequately.

Since in such a case an error occurs when self-location is determined in the three-sensor mode using the output of the wheel speed sensor22, the user is enabled to select the sensor in response to the circumstances, more specifically is enabled to select the single-sensor mode, by inputting an instruction from the outside. Note that the instruction from the outside is not limited to an instruction from the user and other persons such as a dealer, worker or the like, but can be an input signal or the like from another apparatus.

Further, it is also possible to forcibly switch to the three-sensor mode in the case where, after the single-sensor mode was determined by the navigation microcomputer14min the processing of S904, the learning period in the new environment is completed and the accuracy of location determination using the wheel speed sensor22is assured.

As explained in the foregoing, the second embodiment is configured to have a navigation apparatus having: a base unit10that is fastenable to a vehicle and is equipped with at least a microcomputer (system microcomputer10i); and a front panel unit14that is attachable to and detachable from the base unit10and is equipped with at least a liquid crystal panel (display)14bdisplaying map data and a microcomputer (navigation microcomputer14m) performing a navigation function to indicate a determined location of the vehicle on the map data, characterized in that: there are provided with at least three sensors (detectors) including a receiver20that receives a GPS signal, a wheel speed sensor22that detects rotational speed of a wheel of the vehicle and a gyrosensor24that detects angular velocity about a vertical axis of the vehicle; and when an instruction regarding the detector or detectors to be used for determining the location of the vehicle is inputted from outside (S900, S902), the microcomputer of the front panel unit14determines the detector or detectors to be used for determining the location of the vehicle in accordance with the instruction from the outside (S904, S906).

As a result, when a radical change the user can readily discern arises in the road surface condition, such as when the tires were changed to tires of a different diameter, e.g., snow tires, or when an ordinary road surface changes to a slippery, icy road surface, the accuracy of vehicle location determination can be further enhanced by enabling selection in response to the change. The remaining configuration and effects are no different from the first embodiment.

Note that, although the case of there being multiple base units10or cradle units12was explained in the forgoing, it is acceptable for there to be a single base unit10or cradle unit12.

INDUSTRIAL APPLICABILITY

According to this invention, in the navigation apparatus having a cradle unit that is fastenable to a vehicle and is equipped with at least a microcomputer; and a front panel unit that is attachable to and detachable from the cradle unit and is equipped with at least a display displaying map data and a microcomputer performing a navigation function to indicate a determined location of the vehicle on the map data, it is configured such that a panel is integrally formed at bottom of the cradle unit to be attachable to the vehicle. With this, a member having a microcomputer performing a navigation function is attachable/detachable to/from the main body, i.e., the base unit, thereby improving ease of use, the member can be easily attached to the dashboard of the vehicle B, and unnatural impression is prevented from arising in the appearance.