JP3499441B2 - In-vehicle navigation system - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a vehicle-mounted navigation system.

[0002]

2. Description of the Related Art FIG. 5 is a block diagram showing an example of a conventional vehicle-mounted navigation system. In FIG. 5, 1
Is a map data storage drive unit, 2 is a data reception unit, 3 is a displacement detection unit, 4 is a system control unit, 5 is a random access memory (RAM) unit, and 6 is a display unit.

The map data storage drive unit 1 is a CD-R.
The map data is read from the map data storage medium such as OM and supplied to the system control unit 4. The data receiving unit 2
GPS (Global Positioning System) GPS receiver 2a for receiving radio waves, car radio 2b for receiving traffic information, and mobile phone 2c for wireless telephone communication.
And the like and supplies map data such as road information and current location information of the vehicle from an external database to the system control unit 4. The displacement detection unit 3 includes a traveling direction detection unit 3a.
And the traveling speed detection unit 3b, and supplies the traveling direction information and traveling speed information of the own vehicle to the system control unit 4.

The system control unit 4 receives map data such as road information and vehicle position information from the data receiving unit 2 and reads map data such as road information from the map data storage medium from the map data storage drive unit 1. , The read position of the vehicle and the read map data are combined and output to the display unit 6. The traveling direction detector 3a and the traveling speed detector 3b of the displacement detector 3
The map displayed on the display unit 6 is corrected based on the information from. The RAM unit 5 is used as a buffer for temporarily storing data when displaying map data.

A conventional vehicle-mounted navigation system using a GPS receiver, a traveling direction sensor and a traveling speed sensor is disclosed in Japanese Patent Application Laid-Open No. 7-218279. In the conventional vehicle-mounted navigation system, the map data storage drive unit is a read-only drive such as a CD-ROM or a DVD (digital versatile disk) -ROM. Also, there is an IC card as a device that can be stored,
Navigation technology using an IC card is disclosed in Japanese Unexamined Patent Publication
Although it is disclosed in Japanese Patent Publication No. 79196, a large amount of data such as map data cannot be stored because the writing capacity is small.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vehicle-mounted navigation system which can write and read map data storage medium and is easy to use.

[0007]

According to a first aspect of the present invention, there is provided a vehicle-mounted navigation system, a map data storage drive unit for writing and reading a map data storage medium, and data from an external database. A data receiving unit for receiving, a state detecting unit for detecting the state of the vehicle, and a control for permitting or prohibiting the writing operation of the map data storage drive unit based on the state of the vehicle detected by the state detecting unit and write control means, said de
Temporarily stores the data received by the data receiving unit
A random access memory unit, and the state detection unit,
The displacement of the vehicle such as vibration is detected as the state of the vehicle,
Note that the random access memory section is for each specified unit block.
In addition, writing to the map data storage medium is successful.
Hold the data until, the write control means,
Storage of the map data via a random access memory unit
Writing is disabled while writing to the drive section.
If writing is allowed after interruption, the random
Of the data stored in the access memory, write
The unit block at the time of interruption or the unit at the time of interruption of writing
From the unit block immediately before the block, the map data
In order to start rewriting to the data storage medium, the map data
And controlling the data storage drive unit .

As described in claim 2, the in-vehicle navigation system according to the present invention is the in-vehicle navigation system according to claim 1, wherein the writing control means has a detection output from the state detection unit equal to or less than a reference value. The write operation of the map data storage drive unit is permitted when the above condition and the write operation is prohibited when the reference value is exceeded.

[0009]

[0010]

[0011]

[0012]

1 is a block diagram showing an embodiment of a vehicle-mounted navigation system according to the present invention.
In FIG. 1, the same components as those in FIG. 5 are designated by the same reference numerals for description. 1 is different from the conventional configuration shown in FIG. 5 in that, firstly, the map data storage drive unit 1 uses a writable DVD-RAM drive or the like, and the system control unit 4 includes a writing control means 4a. is there. A writable DVD driven by the map data storage drive unit 1-
As an example of RAM, a DVD-RAM disc as shown in FIG. 2 is shown. In FIG. 2, the DVD-RAM 7 has a central hole 7a, and a reproducing layer 7c and a recording layer 7 are provided between the front and back protective layers (polycarbonate layers) 7b and 7e.
It is a dual layer disc with d. In the reproduction layer 7c,
Similar to the conventional CD-ROM and DVD-ROM, map data and the like are already recorded as read-only. The recording layer 7d is a recording layer that can be additionally written by the user later.

The second point in FIG. 1 different from the conventional configuration shown in FIG. 5 is the configuration in which a vibration detecting section 3c is added to the displacement detecting section 3. When data is recorded on the DVD-RAM 7 while the vehicle is traveling, it is considered to be extremely difficult because vibration is frequently generated. Therefore, writing control which is advantageous when a recording device such as an optical disk device which is susceptible to vibration is used. Write control means 4 of the system control unit 4 of FIG.
a is a map data storage drive unit when the vibration or the like is equal to or less than a predetermined reference value for a certain period of time or more by a detection signal from the vibration detection unit 3c of the displacement detecting unit 3 that detects the displacement of the vehicle vibration or the like The write operation of 1 is controlled to be permitted.

When the road condition is unpaved, the vibration interval is short and the probability of the next occurrence is high. Further, when traveling at a speed close to a constant speed such as an expressway or a main road and the road surface condition is good, vibration does not occur for a relatively long time, and the probability of next vibration is low. Utilizing this, the vibration detection unit 3c determines the interval at which vibration during traveling occurs.
Also, the writing control means 4a monitors and controls the writing operation when the vibration is equal to or more than a predetermined time and equal to or less than the reference value. Then, when a displacement such as a vibration exceeding a reference value is detected during traveling, the writing control means 4a controls to immediately prohibit (stop) writing in the map data storage drive unit 1. When writing is stopped, the laser power from the pickup in the map data storage drive unit 1 is lowered to the level for reading. This is because the laser power during writing is higher than that during reading, and if vibration is applied as it is, a track jump may occur and the already recorded data area may be damaged.

[0015]

FIG. 3 is a block diagram showing another embodiment of the vehicle-mounted navigation system according to the present invention. In FIG. 3, instead of the vibration detection unit 3c of FIG. 1, a stop detection unit 8 including a side brake detection unit 8a, a brake pedal detection unit 8b, and a tire rotation detection unit 8c is provided.

When the vehicle stops running, for example, when the vehicle is temporarily stopped by waiting for a signal, or when the vehicle is temporarily parked on the road, when there is almost no vibration in the vehicle,
The write operation of the map data storage drive unit 1 is permitted. That is, whether the side brake detector 8a detects that the side brake is applied,
Alternatively, when the brake pedal detection unit 8b detects that the brake pedal is stepped on and the tire rotation detection unit 8c detects that the tire rotation has stopped, the writing control unit 4a causes the map data storage drive unit 1 to operate. The write operation is controlled to be permitted. Further, if the side brake detection unit 8a or the brake pedal detection unit 8b detects that the foot is released from the brake pedal or the side brake is released at the time of stop, it is highly possible that the vehicle starts running. Based on the detection output, the writing control means 4a disables the writing operation of the map data storage drive unit 1.

Although some embodiments of the present invention have been described above, the present invention is not limited to these and various modifications can be made. For example, in FIG. 1 or FIG. 3, the writing control means 4a is operated based on the bad road information recorded in the map data storage medium by the map data storage drive unit 1 or the bad road information from the external database by the data receiving unit 2. It is also possible to set conditions for permitting (starting) or prohibiting (stopping) writing of the map data storage drive unit 1. That is, depending on the information contained in the map data, such as whether the road in operation is unpaved or under construction, the highway, the type of road width, etc., writing is temporarily prohibited. The write control means 4a is capable of changing or setting the length of the determination time at the time of detection.

Further, in FIG. 1 or FIG. 3, the information of the data receiving section 2 is temporarily stored in the RAM section 5,
DVD by the map data storage drive unit 1 via the unit 5
-When writing is prohibited during writing to the RAM 7, the head address of the unit block of which the writing is suspended in the map data storage drive unit 1 is stored and the start address of the RAM unit 5 corresponding to the unit block is stored. The write control means 4a controls so as to rewrite the data from the protected unit address of the RAM section 5 which is protected from the data and which is stored when the data write is permitted. be able to.

An example of the memory map of the RAM section 5 and the sector structure of the map data storage drive section 1 (recording layer 7d of the DVD-RAM 7) in this case is shown in FIG. The data of the RAM section 5 is the information from the data receiving section 2. Recording on the drive unit 1 (recording layer 7d) is performed for each ECC block. One ECC block has 16 sectors, and the data amount of one sector is 2K.
B. Here, the unit block is data of one ECC block. The sector header area is a portion where sector address information and the like are recorded. RAM, for example
While recording the data of section 5 to sector 2 of drive section 1,
When the write control means 4a makes the state prohibited (stop), the address of the head address (sector 0) of one ECC block of the drive unit 1 is stored. And this 1E
The data of the RAM section 5 corresponding to the data of the CC block (data 〓 is protected so as not to be overwritten, etc., and the head address 0 of the RAM section 5 is stored.
When the write control means 4a is in the write enable (start) state again, the data of the address 0 of the RAM section is rewritten from the sector 0 of the drive section 1 again.

By doing so, the data of the sector 1 immediately before the vibration is overwritten, and the reliability of the data is improved. Further, since the minimum unit of error correction is one ECC block, the reliability of data when read is also improved.
In some cases, when data is continuously written and vibration occurs in the sector 16, it is possible to protect the data up to the sector 0 of the immediately preceding 1ECC block and overwrite all of the data to obtain more reliable data. .

As described above, since the data recording is performed for each unit block and the data is held in the RAM section 5 until the writing of the unit block is successful,
Even if the writing is interrupted by the vibration during writing, the block can be rewritten again, so that the loss of data can be prevented.

Further, in FIG. 1 or FIG. 3, the latest map data and related information are stored in the mobile phone 2a of the data receiving unit 2.
A large amount of data, etc. obtained from the Internet etc. via the DVD, even while the car is running (including when stopped)
-It can be safely stored in RAM. DVD-RA
When the M7 two-layer disc is used, the latest additional information corresponding to the region and the updated map can be recorded in association with each other, which improves usability. Further, the information obtained by the mobile phone 2a or the like is not displayed once and the information is not completely displayed, and the backup can be always taken, so that the information does not have to be accessed many times.

[0023]

According to the present invention, it is possible to obtain a vehicle-mounted navigation system which can write and read the map data storage medium and is easy to use.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a vehicle-mounted navigation system according to the present invention.

FIG. 2 is a schematic diagram showing a structural example of a writable DVD-RAM.

FIG. 3 is a block diagram showing another embodiment of the vehicle-mounted navigation system according to the present invention.

FIG. 4 is a schematic diagram showing an example of a memory map of a RAM section and a sector structure of a map data storage drive section (recording layer of DVD-RAM).

FIG. 5 is a block diagram showing an example of a conventional vehicle-mounted navigation system.

[Explanation of symbols]

1 Map data storage drive section 2 Data receiver 2a mobile phone 2b car radio 2c GPS receiver 3 Displacement detector 3a Running direction detector 3b Running speed detector 3c Vibration detector 4 System control unit 4a Writing control means 5 Random access memory (RAM) section 6 Display 7 DVD-RAM 8 Stop detection section 8a Side brake detector 8b Brake pedal detector 8c Tire rotation detector

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G08G 1/0969 G01C 21/00 G11B 19/02 501

Claims (2)

(57) [Claims] 1. A map data storage drive unit that drives writing and reading of a map data storage medium, a data reception unit that receives data from an external database, a state detection unit that detects the state of a vehicle, and the state detection unit. Write control means for controlling the write operation of the map data storage drive unit based on the state of the vehicle detected by the data control unit, and the data received by the data receiving unit.
A random access memory unit for temporarily storing the state of the vehicle, and the state detection unit determines the state of the vehicle such as vibration of the vehicle.
Of the predetermined unit block
Each time, writing to the map data storage medium is successful.
The write control means holds the data until the random access memory unit
While writing to the map data storage drive unit via
Write is allowed after the write is disabled and write is suspended.
If yes, it is stored in the random access memory section.
Of the existing data, the unit block at the time of writing interruption
Alternatively, the unit block immediately before the unit block at the time of writing interruption
Rewriting from the block to the map data storage medium
Control the map data storage drive unit to start
An in-vehicle navigation system characterized by: 2. The in-vehicle navigation system according to claim 1, wherein the writing control unit permits the writing operation of the map data storage drive unit when the detection output from the state detection unit is less than or equal to a reference value. In addition, an in-vehicle navigation system characterized by prohibiting a writing operation when a reference value is exceeded.