JP4188735B2 - Navigation device, method and program - Google Patents

Description

Offset:0x1BE から、１６バイト分、パーティションテーブルがある。パーティションテーブルは最大４テーブルまで記録が可能で、通常は２つ使用する。
【００６８】
パーティションテーブルの１エントリは、アクティブフラグ（１バイト）、ＣＨＳによる開始セクタ（３バイト）、パーティションタイプ（１バイト）、ＣＨＳによる終了セクタ（３バイト）、ＬＢＡによる開始セクタ（４バイト）、パーティションサイズ（４バイト）となる。パーティションエントリがいくつかは、最大４つで、パーティションタイプ＝０になるまでで判断する。
【００６９】
パーティションタイプは、以下の通りであるが、ここでは、値以外は省略している。
【００７０】
【表２】

【００７１】
〔４−２．ＦＡＴの基本構成〕
続いて、一つのパーティションにおけるＦＡＴの基本構成を図４に示す。このなかでＢＰＢは、ＢＩＯＳパラメータブロックすなわちブートセクタのことであり、ＢＰＢの実例として、例えばＦＡＴ３２の場合、以下のようになっている。
【００７２】
【表３】

Offset:0x00, Size: 3 ジャンプ命令ＯＳをロードするためのジャンプ命令が書き込まれる。
Offset:0x03, Size: 8 OEM ラベル名
フォーマットを行ったＯＳやバージョン。Windows（登録商標）95 OSR2 以降は、「MSWIN4.1」、それ以前は「MSWIN4.0」。FAT16の場合は、「MSDOS5.0」などとなる。
Offset:0x0B, Size:2 論理セクタサイズ
論理ドライブの１セクタあたりのバイト数。通常は、0x0200（512バイト／セクタ）。
Offset:0x0D, Size:1 １クラスタあたりのセクタ数
0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80 のどれかが使用される。
Offset:0x0E, Size:2 予約セクタ数
セクタ０からＦＡＴ領域の直前までのセクタ数。すなわちメインＦＡＴの開始セクタ番号を表す。
Offset:0x10, Size:1 ＦＡＴの数
ディスクに存在するＦＡＴの組の数。通常は、予備ＦＡＴを一つ持ち、２。
Offset:0x11, Size:2 ルートディレクトリエントリの最大数
FAT12/16 用であり、FAT32では、常に 0x0000 となる。
Offset:0x13, Size:2 全セクタ数
FAT12/16 用であり、FAT32では、常に 0x0000 となる。
Offset:0x15, Size:1 メディアディスクリプタ
メディアの種類を示すフラグ。以下の数値が使用される。
【００７３】
【表４】

Offset:0x16, Size:2 ＦＡＴのセクタ数
FAT12/16用であり、FAT32では、常に 0x0000 となる。
Offset:0x18, Size: 2 １トラックあたりのセクタ数
Offset:0x1A, Size: 2 ドライブのヘッド数
ドライブの物理的な情報を表すパラメータ。
Offset:0x1C, Size:4 不可視セクタ数
論理ドライブの先頭セクタ直前までの物理ドライブのセクタ数。
Offset:0x20, Size:4 全セクタ数
Offset:0x13 のセクタ数が０の場合、こちらのセクタ数が有効（FAT32用）。
Offset:0x24, Size:4 １つのＦＡＴあたりのセクタ数
FAT32用。
Offset:0x28, Size:2 メディアディスクリプションフラグ
FAT32用。通常は、0x0000 が書き込まれており、ミラーリングを行うと、bit7 が 1 になって bit3-0 にアクティブＦＡＴ番号が入る。
Offset:0x2A, Size:4 ルートディレクトリの開始クラスタ
FAT32用。特に意図しない限りは、0x00000002 が書き込まれ、FAT領域の直後になる。
Offset:0x30, Size:2 ファイルシステム情報のセクタ番号
FAT32用。FSINFOのセクタ番号を表す。
Offset:0x32, Size:2 ブートセクタのコピーのセクタ番号
FAT32用。論理ドライブの先頭セクタが壊れているときに使われるブートセクタのコピーの位置を表す。
Offset:0x34, Size:6 予約エリア
FAT32用。
Offset:0x40（FAT32）、0x24（FAT12/16）, Size:1 物理ドライブ番号
ハードディスクの場合 0x80 が通常書き込まれる。
Offset:0x41（FAT32）、0x25（FAT12/16）, Size:1 予約エリア
Offset:0x42（FAT32）、0x26（FAT12/16）, Size:1 ブートシグネチャ
0x29 の場合は、ボリュームシリアル番号を持つ。
Offset:0x43（FAT32）、0x27（FAT12/16）, Size:4 ボリュームシリアルID
フォーマット時にランダムに割り当てられるシリアルナンバー。
Offset:0x47（FAT32）、0x2B（FAT12/16）, Size:11 ボリュームラベル
Offset:0x52（FAT32）、0x36（FAT12/16）, Size:8 ファイルシステムタイプ
通常、「FAT32」／「FAT16」／「FAT12」のいずれかが書き込まれる。
Offset:0x1FE, Size:2 マジックナンバー
0x55AA が書き込まれる。
【００７４】
〔４−３．ＦＳＩＮＦＯ（ファイル記述子）〕
ＦＡＴ３２では、論理セクタ番号１にＦＳＩＮＦＯと呼ばれる領域を持っている。ＦＡＴ１２／１６では、空き容量を計算するためにはＦＡＴをすべて読み出して未使用クラスタ数を数えなければならなかったが、ＦＡＴ３２ではこのＦＳＩＮＦＯに空きクラスタ数を書き込むことで空き容量の計算速度が向上している。ＦＳＩＮＦＯの実際は、以下のようになっている。
【００７５】
【表５】

Offset:0x1E4, Size:4 ファイルシステムシグネチャ
0x61417272（rrAa）に固定。
Offset:0x1E8, Size:4 空きクラスタ数
空きクラスタが計算されていないときは、0xFFFFFFFF が書き込まれる。
Offset:0x1EC, Size:4 最終書き込みクラスタ番号
Offset:0x1F0, Size:6 予約エリア
Offset:0x1FE, Size:2 マジックナンバー
0x55AA が書き込まれる。
【００７６】
〔４−４．ＦＡＴ領域（ＦＡＴ−１とＦＡＴ−２）〕
ＦＡＴ領域は、各ＦＡＴエントリが対応するクラスタ順に並んでいる領域である。各ＦＡＴエントリはクラスタに１対１に対応しており、ＦＡＴエントリを参照することで対応するクラスタがどのような状態か（使用中、空きなど）を知ることができる。ＦＡＴ領域の実際を次に示す。
【００７７】
【表６】
[00000000] F8 FF FF 0F FF FF FF 7F FF FF FF 0F FF FF FF 0F |
[00000010] 06 00 00 00 FF FF FF 0F FF FF FF 0F FF FF FF 0F |
[00000020] FF FF FF 0F 77 00 00 00 0B 00 00 00 FF FF FF 0F |
[00000030] 12 0F 00 00 FF FF FF 0F FF FF FF 0F FF FF FF 0F |
[00000040] FF FF FF 0F FF FF FF 0F 6E 06 00 00 FF FF FF 0F |
[00000050] FF FF FF 0F FF FF FF 0F FF FF FF 0F FF FF FF 0F |
【００７８】
ＦＡＴ３２のクラスタは、４Ｂｙｔｅｓ（３２ビット）で表されるので、ＦＡＴエントリも４Ｂｙｔｅｓずつ区切って読み出されることになる。上のＯｆｆｓｅｔ ０ｘ１０，Ｓｉｚｅ４のエントリはクラスタ番号４のエントリで、クラスタ番号６が続いていることを示している。
【００７９】
また、ＦＡＴエントリの意味を次に示す。
【表７】

【００８０】
〔４−５．ディレクトリエントリ〕
ディレクトリエントリは、そのディレクトリ内にあるファイルの情報を記録する場所である。ルートディレクトリの情報は、ＦＡＴ３２では、通常クラスタ番号２がルートディレクトリエントリとなりデータ領域に記録される。ＦＡＴ１２／１６では、ルートディレクトリエントリは、フォーマット時に領域が確保される。
【００８１】
サブディレクトリは、データ領域に確保される。ディレクトリエントリは、先頭から各ファイルごとに３２バイトずつ割り当てられる。ディレクトリエントリが多くなるとクラスタチェーンを作成し、別のクラスタに続きを作成する。ディレクトリエントリの実際を次に示す。なお、次の表８ではアドレス前半４桁の「００００」は省略とする。
【００８２】
【表８】
[00C0] 42 4F 4F 54 20 20 20 20 49 4E 49 26 18 69 23 92 | BOOT INI
[00D0] 82 2B 90 9B 05 00 01 9A 82 2B C6 D6 C1 00 00 00 |
[00E0] 42 20 00 53 00 65 00 74 00 74 00 0F 00 4A 69 00 | B S e t t Ji
[00F0] 6E 00 67 00 73 00 00 00 FF FF 00 00 FF FF FF FF | n g s
[0100] 01 44 00 6F 00 63 00 75 00 6D 00 0F 00 4A 65 00 | D o c u m Je
[0110] 6E 00 74 00 73 00 20 00 61 00 00 00 6E 00 64 00 | n t s a n d
[0120] 44 4F 43 55 4D 45 7E 31 20 20 20 10 00 3D 42 92 | DOCUME~1 =B
[0130] 82 2B 88 2B 00 00 43 92 82 2B E6 50 00 00 00 00 |
Offset:0x00, Size:8 ファイル名
Offset:0x08, Size:3 拡張子
MS-DOS 形式 8.3 ファイル名が記録される。それぞれ、８文字、３文字に満たない場合は残りがスペース（0x20）で埋められる。先頭バイトが 0xE5 のとき、そのファイルが削除済みであることを示す。
Offset:0x0B, Size:1 ファイル属性
このファイル属性は、以下の数値の和で表される。但し、0x0F の場合のみ、ロングファイルを表す。
【００８３】
【表９】

Offset:0x0C, Size:1 予約エリア
大小文字フラグとして、Windows（登録商標）NT で使用される。
Offset:0x0D, Size:1 作成時刻（10ms単位）
Offset:0x0E, Size:2 作成時刻
Offset:0x10, Size:2 作成日付
Offset:0x12, Size:2 アクセス日付
Offset:0x14, Size:2 ファイルの先頭クラスタ番号の上位２バイト
FAT32用。
Offset:0x16, Size:2 更新時刻
Offset:0x18, Size:2 更新日付
Offset:0x1A, Size:2 ファイルの先頭クラスタ番号の下位２バイト
Offset:0x1C, Size:4 ファイルサイズ
【００８４】
〔５．論理エラーのチェック方法〕
以上の前提において、論理エラーのチェックを行うには、その領域の「ＦＡＴ−１」と「ＦＡＴ−２」の内容が互いに一致するか否かを比較したり、ＦＡＴのセクタ番号異常をチェックすることが考えられる。前者では、「ＦＡＴ−１」と「ＦＡＴ−２」が、本来、同じでなければならないものをチェックし、異なる場合、いずれかに他を合わせることで修復を行う。
【００８５】
このような本実施形態では、ＦＡＴの共通性という単純な基準で論理エラーの有無を確実容易にチェックできる利点がある。また、本実施形態では、複数のＦＡＴ間の不一致があっても、いずれかに統一するという単純な手法により確実容易に修復を行える利点がある。
【００８６】
またＦＡＴのセクタ番号異常に基く後者では、「ＦＡＴ−１」、「ＦＡＴ−２」が示すクラスタ番号が異常な取り得ない値、例えば最大クラスタ番号を越えているか否かをチェックし、そのような論理エラーに対しては、該当するクラスタ番号についてそこを未使用領域又は最終使用領域とする。
【００８７】
このように本実施形態では、ＦＡＴ中のセクタ番号又はクラスタ番号の異常の有無という単純な基準で論理エラーの有無を確実容易にチェックできる利点がある。また、本実施形態では、クラスタ番号が最大クラスタ番号を超えていても、そこを未使用領域又は最終使用領域とするという単純な手法により確実容易に修復を行える利点がある。
【００８８】
具体的なチェックや修復の手法としては、従来知られたいかなるものを選択してもよいが、例えばディレクトリ情報、ファイル情報と「ＦＡＴ−１」、「ＦＡＴ−２」の関連がおかしいかどうか等のチェックを用いることも可能である。このようにすれば、ディレクトリ又はファイルの情報と、ＦＡＴの関連が正常か異常かという単純な基準で、論理エラーの検出や修復を確実容易に行える利点がある。
【００８９】
〔６．効果〕
以上のように、本実施形態では、ハードディスクドライブ等の読み書き可能な大容量外部記憶手段を複数の領域に分け、予期せぬ電源断による書込み途中など、記録データの論理的フォーマットの異常すなわち論理エラーやその可能性が検出された場合、その領域へのエラーチェックや修復の間、他の領域のデータを用いてナビゲーション処理の少なくとも一部を実行できるので、使い勝手が向上する。
【００９０】
また、本実施形態では、主な記憶領域に論理エラーやその可能性が検出されても、そのエラーチェックや修復の間、予備記憶領域からバックアップ用の道路地図データ等を読み出すことで、自車位置と周辺地図表示などある程度のナビゲーション処理が可能となるので、ユーザは常に自車位置がわかり、使い勝手が向上する。
【００９１】
また、本実施形態では、書込みフラグを用いた簡易な構成により論理エラーの可能性を確実容易に検出できる利点がある。
【００９２】
また、本実施形態では、修復部４７の作用により、修理に出したりユーザに特別な知識や処置を要求することなく、領域やデータの自己修復により論理エラーを自動解消し正常な状態へ早期に復帰できる利点がある。
【００９３】
〔７．他の実施形態〕
なお、本発明は上記実施形態に限定されるものではなく、次に例示するような他の実施形態も含むものである。例えば、情報の記憶手段はハードディスクには限定されず、ＤＶＤ−ＲＡＭやＤＶＤ−ＲＷ、各種フラッシュメモリカードなどでもよいし、また、ドライブの論理フォーマット、論理エラーの態様、チェックや修復の内容などは、上記実施形態に示したものは一例に過ぎず、自由に他のものを選択可能である。また、上記実施形態では、ハードディスクドライブの領域を２つのパーティションに分け、常に自車位置付近の道路地図データを一方のパーティションに保存する例を説明したが、保存先はＳＲＡＭのような不揮発性メモリでもよい。
【００９４】
また、一方のパーティションについて、ある程度の領域を確保し、可能性の考えられる範囲、例えば日本全国について、ある一定レベルの道路地図データを予め最初から入れておいてもよい。このようにすれば、常に自車位置付近の道路地図データを一方のパーティションにバックアップするようなことが必要ないので、システム負荷が軽減される等の利点がある。また、周辺地図表示「又はそれに準じた所定の処理」は、要所での進行方向案内など自由に選択しうる。
【００９５】
【発明の効果】
以上のように、この発明によれば、少なくとも自車周辺の地図表示など一定のナビゲーション動作が可能なナビゲーション装置、方法及びプログラムを提供することができる。
【図面の簡単な説明】
【図１】本発明の実施形態の構成を示す機能ブロック図。
【図２】本発明の実施形態における処理手順を示すフローチャート。
【図３】本発明の実施形態におけるハードディスクドライブの論理フォーマットの概要を示す概念図。
【図４】本発明の実施形態におけるＦＡＴの基本構成を示す概念図。
【符号の説明】
１…絶対位置・方位検出部
２…相対方位検出部
３…車速検出部
４…メインＣＰＵ及びその周辺回路
Ｍ…メモリ群
５…ＲＯＭ
６…ＤＲＡＭ
７…ＳＲＡＭ
８…ＶＲＡＭ
９…ユーザインタフェース部
１０…表示部
１１…入力部
１２…ＨＤＤ制御部
１３…ＦＭ多重受信及び処理部
１４…光／ビーコン受信及び処理部
Ｍ…メモリ群
４０…現在位置検出部
４１…目的地指定部
４２…経路設定部
４３…地図表示部
４４…案内制御部
４５…管理検出部
４６…バックアップ制御部
４７…修復部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a navigation device, method, and program capable of at least a certain navigation operation such as a map display around a host vehicle even during a logic error check and repair.
[0002]
[Prior art]
In recent years, with the spread of automobiles and the advancement of digital technology, navigation technology has rapidly spread. For navigation, devices such as in-vehicle devices use road map data to detect the position of the vehicle sequentially with GPS and display it on the surrounding map, search for the optimum guidance route to the specified destination, Accordingly, the direction of travel and the like are guided and guided by a screen display or synthesized voice.
[0003]
In early navigation devices, read-only CD-ROMs, DVD-ROMs, etc. are used in an external storage device for storing road map data and the like. A small amount of data is stored in the nonvolatile memory. However, in recent years, a large-capacity hard disk drive (simply "" as a readable / writable storage device due to the increase in road map data capacity and the demand for storing large amounts of data such as travel routes after the start of use. The number of devices using “hard disk” or HDD is increasing (see, for example, Patent Document 1).
[0004]
[Patent Document 1]
JP 2002-365063 A
[0005]
[Problems to be solved by the invention]
By the way, in a readable and writable mass storage means such as a hard disk, it is essential to correctly maintain the logical format of data centered on management information such as FAT (File Allocation Table) and directories. FAT16, FAT32, NTFS, etc. are known as representative formats.
[0006]
However, for some reason, for example, when the data could only be stored halfway due to an inadvertent power interruption during data writing, an error such as inconsistency in the data logical format as described above (hereinafter referred to as “logical error”). May occur. Such logical errors prevent file access from an application program in a personal computer (PC), and in some cases prevent normal startup of the OS, which is basic software, and read / write data from a navigation program in a navigation device. It causes troubles such as obstruction.
[0007]
Therefore, some PCs, for example, check for the presence or absence of a logical error when they detect that the OS termination process has not been completed at the next startup, and repair them if necessary. If the logical error is resolved by such check and repair, the file can be accessed from the application. The time required for such checks and repairs varies depending on CPU performance, hard disk capacity, etc. PCs are originally complex systems used for various purposes in calm environments such as homes and offices. Even if it takes some time to check and repair, the user does not feel uncomfortable waiting. In addition, the power supply is stable in an environment such as a home or office where a lot of PCs are used, and there are few causes of logic errors such as unexpected power cuts in the first place.
[0008]
However, these circumstances are different in navigation devices.First, since there are many users who travel immediately after starting the car engine, the navigation device is particularly required to be responsive. Need to be able to see where the road is running. For this reason, if the check and repair functions of the PC as described above are brought into the navigation device as they are, a map or the like will not be displayed on the screen during the check or repair of the logic error, which is very troublesome for the user and very uncomfortable. There was a problem felt.
[0009]
Also, in automobiles where navigation devices are often used, the power supply stability is not as good as at home or in the office, and the power is suddenly turned off by the user's ignition key operation. There are many instability factors such as a momentary interruption due to disturbance, and if a writable storage device is used, the trigger of a logic error is much greater than that of a PC.
[0010]
The present invention solves the problems of the prior art as described above, and its purpose is to provide a navigation device capable of at least a certain navigation operation such as a map display around the own vehicle even during a logical error check and repair, It is to provide a method and program.
[0011]
[Means for Solving the Problems]
  In order to achieve the above object, the invention of claim 1In a navigation apparatus that performs navigation processing using readable and writable information storage means, the information storage means includes a main storage area for storing data necessary for the navigation processing, and road map data in the vicinity of the position of the traveling vehicle A flag indicating which area is to be written in a predetermined nonvolatile memory at the start of writing to the information storage means, and resetting the flag at the end of writing A management detecting means for determining which area may have a logic error by checking the flag when the apparatus is started, and a repairing means for repairing if there is a logic error in the main storage area. The management detection means, if a write flag is not set in the non-volatile memory at the time of startup of the device, When normal navigation processing is performed using data in a storage area and a write flag is set in the non-volatile memory when the apparatus is started up, and this flag relates to the main storage area, the main storage area A logical error in the storage area is checked, the logical error in the main storage area is checked, and navigation processing is performed using road map data in the vicinity of the vehicle position stored in the spare storage area. When the logical error check in the main storage area and the repair by the repairing unit are completed, the system starts using the data in the main storage area and performs normal navigation processing. .
[0012]
  Claim 3The invention of No. 1 is based on the view of the invention of claim 1 as a method.In the navigation method for performing navigation processing using readable / writable information storage means, the information storage means includes a main storage area for storing data necessary for the navigation processing, and road map data in the vicinity of the position of the host vehicle during traveling. Only when the computer starts writing to the information storage means, sets a flag indicating which area to write in a predetermined nonvolatile memory, and sets the flag at the end of writing. A management detection step of determining which area has a logical error by resetting and checking the flag at the time of starting the apparatus; and a repairing step of repairing if there is a logical error in the main storage area; The management detection step is performed in the nonvolatile memory when the apparatus is started up. When the flag is not set, a normal navigation process is performed using the data in the main storage area, and a write flag is set in the non-volatile memory when the apparatus is started. If it is related to the main storage area, it is determined that there is a possibility of a logical error in the main storage area, and the logical error of the main storage area is checked and stored in the spare storage area. Data in the main storage area when the navigation processing using the road map data in the vicinity of the vehicle position and the logical error check in the main storage area and the repair in the repair process are completed. And a step of performing normal navigation processing by starting up using.
[0013]
  Claim 5The invention of claim 13From the perspective of a computer program,In a navigation program for causing a computer to perform navigation processing using readable / writable information storage means, the information storage means includes a main storage area for storing data necessary for the navigation processing, and a location near the position of the host vehicle during traveling. It consists of a preliminary storage area that stores only road map data, and the program sets a flag in a predetermined nonvolatile memory indicating to which area to write to the computer when writing to the information storage means is started. When the writing is completed, the flag is reset and the flag is checked when the device is started to determine which area has the possibility of a logical error, and the main storage area has a logical error. A recovery function that repairs if there is, the management detection function, If a write flag is not set in the non-volatile memory when the device is started up, a function for performing normal navigation processing using the data in the main storage area, and writing into the non-volatile memory at the start-up of the device If a flag is set and this flag relates to the main storage area, it is determined that there is a possibility of a logical error in the main storage area, and the logical error of the main storage area is checked. And performing the navigation processing using the road map data near the vehicle position stored in the spare storage area, and the logical error check in the main storage area and the repair in the repair process are completed. And a function of starting using the data in the main storage area and performing normal navigation processing.
[0014]
  More thanIn the mode, the readable / writable large-capacity external storage means such as a hard disk drive is divided into a plurality of areas, and abnormalities in the logical format of the recorded data, that is, logical errors and the possibility of such errors are detected, such as during writing due to unexpected power interruption In such a case, during the error check or repair of the area, at least a part of the navigation process can be executed using the data of the other area, so that the usability is improved.
[0018]
  AlsoEven if a logical error or its possibility is detected in the main storage area, the vehicle position and surrounding map are displayed by reading backup road map data etc. from the spare storage area during the error check and repair. Therefore, the user can always know the position of the vehicle and the usability is improved.
[0022]
  furtherThere is an advantage that the possibility of a logic error can be easily and reliably detected by a simple configuration using a write flag.
[0041]
  Claim2, Claims1In the navigation device according to claim 1,Repair meansIt is characterized by comprising an informing means for informing that the restoration is in progress.
[0042]
  Claim4The invention of claim2The invention from the perspective of a method, and claims3The navigation method according to claim 1, wherein the computerA notifying step for notifying that the repairing step is being performed is executed.
[0043]
  Claim6The invention of claim2, 4From the perspective of a computer program,The navigation program according to claim 5, wherein the computer is caused to realize a notification function for notifying that the repair is being performed in the repair function.
[0044]
In these aspects, by notifying the user that restoration is in progress, it is known in advance that only a part of functions such as backup processing will work, and user confusion is prevented.
[0045]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention (hereinafter referred to as “embodiment”) will be specifically described with reference to the drawings. Although this embodiment can be realized by controlling a computer with a program, the hardware and program implementation modes in this case can be changed in various ways. Therefore, in the following description, each of the present invention and this embodiment will be described. A virtual circuit block that realizes the function is used.
[0046]
[1. Hardware configuration)
The present embodiment shows a navigation device (hereinafter referred to as “the present device”) of the present invention, and can be grasped as a method and a program, and a recording medium recording such a program. It is also an aspect of the present invention that the navigation system of each vehicle is downloaded and executed via a communication network such as a telephone network.
[0047]
[1-1. overall structure〕
First, this apparatus is a navigation apparatus that performs navigation processing using a hard disk drive (HDD) that is a readable / writable information storage means, and includes the following elements shown in the functional block diagram of FIG. That is, the absolute position / orientation detection unit 1 calculates the absolute position coordinates and direction on the ground surface with respect to the current position of the automobile (referred to as the own vehicle) on which the apparatus is mounted, that is, the own vehicle position. This is a part for receiving GPS radio waves transmitted from GPS satellites with an antenna or a receiver. The relative orientation detection unit 2 is a part for detecting the relative orientation of the host vehicle using a gyro. The vehicle speed detector 3 is a part that calculates the speed of the host vehicle by processing vehicle speed pulses obtained from the automobile.
[0048]
The main CPU and its peripheral circuit 4 are parts that serve as a control circuit for controlling the entire apparatus. The memory group M is various memories necessary for the operation of the apparatus. For example, the ROM 5 for storing a program is accessed by the main CPU when the apparatus is activated. A main program is loaded into a dynamic RAM (DRAM) 6 that provides a work area and the like. The SRAM (static RAM) 7 is a storage means for storing various settings, information such as flags, etc., and is backed up by the battery even when the main power is turned off, and provides memory contents when the power is turned on. However, it can be replaced by other storage means such as a flash memory or a hard disk drive. A display VRAM (video RAM) 8 stores bitmap data of an image to be displayed on the display unit 10.
[0049]
The display unit 10 is a part for displaying various information such as a map and an operation menu on a liquid crystal display screen (not shown), and is preferably used in combination with speech synthesis. The input unit 11 is a part for a user to input information such as a command from a switch or the like, and includes a touch sensor function, a remote control unit, an infrared transmission / reception unit, and the like. The user interface unit 9 is a user interface that connects the display unit 10 and the input unit 11 to the main CPU and its peripheral circuit 4 using an I / O control circuit, a device driver, or the like. The HDD control unit 12 is means for reading and writing the hard disk drive.
[0050]
The FM multiplex reception and processing unit 13 is a part that receives FM broadcast waves and extracts desired data such as traffic information of the VICS service from the broadcast waves. The traffic information includes traffic jam information. The optical / beacon reception and processing unit 14 is a part that receives and processes information such as identification information of each beacon and traffic information of the VICS service from an optical beacon or a radio wave beacon installed on a roadside.
[0051]
[1-2. Role of main CPU and its peripheral circuits]
Further, the main CPU and its peripheral circuit 4 are configured to realize the roles as the following parts shown in FIG. 1 by the action of the program as described above. That is, the current position detection unit 40 is means for sequentially calculating the vehicle position, and specifically, is configured to calculate the vehicle position by combining GPS navigation positioning and autonomous navigation positioning.
[0052]
Here, in GPS navigation positioning, the current position is calculated using information obtained by the absolute position / orientation detection unit 1 based on radio waves from an artificial satellite. In the autonomous navigation positioning, the current position is calculated using information obtained from the relative bearing detection unit 2 and the vehicle speed detection unit 3 based on the geomagnetism and the speed of the host vehicle.
[0053]
The destination specifying unit 41 is a means for receiving an input of a destination by searching for a facility from a database or specifying a cursor on a map, and the route setting unit 42 displays a route to the input destination. It is a means for setting a route obtained as a result by calculating based on road map data or entrusting calculation to a predetermined server via communication. In addition, the map display unit 43 displays the vehicle position on a surrounding map and at least a part of the route on the display unit 10 based on the calculated vehicle position and the road map data, or three-dimensionally. The guidance control unit 44 controls the guidance guidance by determining elements to be displayed in the route, elements such as blinking emphasis, and combined speech.
[0054]
The management detection unit 45 is a unit that manages the storage area in the HDD control unit 12 into a plurality of areas and detects at least the possibility of a logical error in each area. In addition, the management detection unit 45 sets a flag indicating in which area to write to the HDD when writing to the HDD is started in a predetermined nonvolatile memory such as the SRAM 7, resets the flag at the end of writing, and sets the flag at startup. It is configured to determine which area has the possibility of a logic error by checking.
[0055]
Further, the backup control unit 46 controls at least a part of the navigation processing by using the data of other regions by controlling the map display unit 43 when the possibility of a logical error is detected in any region. This means is executed as a backup process. The repair unit 47 is a data repair unit that repairs at least one of an area or data related to the logical error during the execution of the backup process.
[0056]
[2. Area configuration on the hard disk)
Next, a state in which the HDD is classified and managed by the management detection unit 45 is shown. That is, in this embodiment, the hard disk is divided into two partitions, and the first partition (0 drive) stores road map data for navigation and other necessary image data as a main storage area. Correspondingly, the destination specifying unit 41, the route setting unit 42, the map display unit 43, and the guidance control unit 44 use the road map data in the 0 drive, which is the main storage area, It is a means for performing map display and other navigation processing.
[0057]
On the other hand, the second partition (1 drive) is used as an area for writing road map data only near the position of the traveling vehicle as a spare storage area. That is, at least one road map data required for displaying the surrounding map is stored in advance or copied from drive 0 which is the main storage area in drive 1 which is the spare storage area. This copying is performed, for example, periodically or every movement to some extent. When the possibility of a logical error is detected for the 0 drive that is the main storage area, the backup control unit 46 uses the road map data in the 1 drive that is the spare storage area to display the surrounding map or A predetermined process conforming to the above is performed as a backup process.
[0058]
[3. (Overview of action)
In the present embodiment configured as described above, whether or not data is being written to the hard disk at the moment when the power supply is cut off is determined as follows at the next start-up, and processing corresponding thereto is performed. Here, the processing procedure relating to the present embodiment is shown in the flowchart of FIG.
[0059]
That is, the management detection unit 45 stores an HDD write flag indicating which drive is to be written in a predetermined area of a nonvolatile memory such as the SRAM 7 at the start of data writing, and sets the flag after the writing is completed. clear. For this reason, immediately after the next power supply, it is checked whether the write flag in the SRAM is set (step 1). If the flag is not set, that is, if the flag is cleared, the main storage area is 0 as it is. The system is activated using the drive and normal navigation processing is performed (step 2). Since data cannot be written to the 0 drive and the 1 drive in parallel, there is no state in which both drives are being written.
[0060]
For the drive whose flag has not been cleared (step 1), data writing has not been completed for some reason and there is a possibility of a logic error. Therefore, the management detection unit 45 is necessary when starting the navigation device. The part is read from the hard disk drive and checked, and if there is an actual logic error, the repair unit 47 performs repair.
[0061]
That is, first, when the standing flag is related to the 0 drive (step 3), it is determined that there has been a circumstance such as the power supply being cut off during the writing of the 0 drive, while the spare storage area is 1 Since the road map data in the vicinity of the vehicle position at the time when the power supply is cut off is stored in the drive, the management detection unit 45 activates the navigation device and then sends the road map data to the backup control unit 46. Tentatively, the backup processing with limited functions is started to display the map around the vehicle position, and the user is informed by text or voice that the restoration is in progress (step 4), and the functions are limited. Make sure that it is being done.
[0062]
As described above, in this embodiment, by notifying the user that restoration is in progress, it is known in advance that only a part of functions such as backup processing will work, thereby preventing confusion for the user.
[0063]
During restoration of the 0 drive by the restoration unit 47, the backup control unit 46 uses the road map data in the 1 drive (step 5). When checking and repairing are normally completed for the 0 drive (step 6), the process returns to the normal processing using the data of the 0 drive (step 7).
[0064]
On the other hand, when the standing flag is related to one drive which is a spare storage area (step 3), the navigation device is started normally using data in the zero drive which is the main storage area, and one drive is Are checked and repaired (step 8), and if one drive is normally repaired, normal navigation processing is started (step 9).
[0065]
[4. Logical format on hard disk)
Next, FIG. 3 shows an outline of a logical format in a normal state for each area of the hard disk, which is a prerequisite for the above check and repair. As shown in this figure, the entire storage area of the hard disk drive is divided into a basic area and an extended area, and the extended area is divided into one or more logical areas, and the extended areas and logical areas have a nested structure. Therefore, it is necessary to sequentially track the boot record of each area from the MBR (Master Boot Record) of the basic area to the EPBR (Extended Partition Boot Record) of the extended area. It is possible to configure a plurality of basic areas.
[0066]
[4-1. MBR and EPBR]
In both MBR and EPBR described above, a partition table is stored from the 446th byte. A code for reading the OS from the disk is recorded up to 446 bytes of MBR. On the other hand, EPBR has no particular meaning up to 446 bytes, and is normally filled with 0x00 or 0x20. Here, an example of the partition table is shown.
[0067]
[Table 1]

There is a partition table for 16 bytes from Offset: 0x1BE. Up to four partition tables can be recorded, and usually two are used.
[0068]
One entry in the partition table includes an active flag (1 byte), a start sector by CHS (3 bytes), a partition type (1 byte), an end sector by CHS (3 bytes), a start sector by LBA (4 bytes), and a partition size. (4 bytes). Some partition entries have a maximum of four, and judgment is made until partition type = 0.
[0069]
The partition type is as follows, but the values other than the values are omitted here.
[0070]
[Table 2]

[0071]
[4-2. Basic configuration of FAT]
Next, FIG. 4 shows the basic configuration of FAT in one partition. Among them, BPB is a BIOS parameter block, that is, a boot sector. As an example of BPB, for example, FAT32 is as follows.
[0072]
[Table 3]

Offset: 0x00, Size: 3 Jump command A jump command for loading the OS is written.
Offset: 0x03, Size: 8 OEM label name
OS and version that have been formatted. Windows® 95 OSR2 or later is “MSWIN4.1”, and earlier is “MSWIN4.0”. For FAT16, it will be "MSDOS5.0".
Offset: 0x0B, Size: 2 Logical sector size
The number of bytes per sector of the logical drive. Normally 0x0200 (512 bytes / sector).
Offset: 0x0D, Size: 1 Number of sectors per cluster
One of 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80 is used.
Offset: 0x0E, Size: 2 Number of reserved sectors
Number of sectors from sector 0 to immediately before the FAT area. That is, it represents the start sector number of the main FAT.
Offset: 0x10, Size: 1 Number of FAT
The number of FAT pairs present on the disk. Usually, it has one spare FAT and 2.
Offset: 0x11, Size: 2 Maximum number of root directory entries
For FAT12 / 16, it is always 0x0000 for FAT32.
Offset: 0x13, Size: 2 Total number of sectors
For FAT12 / 16, it is always 0x0000 for FAT32.
Offset: 0x15, Size: 1 Media descriptor
Flag that indicates the media type. The following numbers are used:
[0073]
[Table 4]

Offset: 0x16, Size: 2 Number of FAT sectors
For FAT12 / 16, it is always 0x0000 for FAT32.
Offset: 0x18, Size: 2 Number of sectors per track
Offset: 0x1A, Size: 2 Number of drive heads
A parameter that represents the physical information of the drive.
Offset: 0x1C, Size: 4 Number of invisible sectors
Number of sectors in the physical drive up to just before the first sector of the logical drive.
Offset: 0x20, Size: 4 Total number of sectors
If the sector number of Offset: 0x13 is 0, this sector number is valid (for FAT32).
Offset: 0x24, Size: 4 Number of sectors per FAT
For FAT32.
Offset: 0x28, Size: 2 Media description flag
For FAT32. Normally, 0x0000 is written. When mirroring is performed, bit7 becomes 1 and active FAT number is entered in bit3-0.
Offset: 0x2A, Size: 4 Start cluster of root directory
For FAT32. Unless otherwise specified, 0x00000002 is written and immediately after the FAT area.
Offset: 0x30, Size: 2 File system information sector number
For FAT32. Indicates the sector number of FSINFO.
Offset: 0x32, Size: 2 Boot sector copy sector number
For FAT32. Represents the location of the boot sector copy used when the first sector of the logical drive is corrupted.
Offset: 0x34, Size: 6 Reserved area
For FAT32.
Offset: 0x40 (FAT32), 0x24 (FAT12 / 16), Size: 1 Physical drive number
For hard disks, 0x80 is normally written.
Offset: 0x41 (FAT32), 0x25 (FAT12 / 16), Size: 1 Reserved area
Offset: 0x42 (FAT32), 0x26 (FAT12 / 16), Size: 1 Boot signature
In case of 0x29, it has a volume serial number.
Offset: 0x43 (FAT32), 0x27 (FAT12 / 16), Size: 4 Volume serial ID
Serial number assigned at random when formatting.
Offset: 0x47 (FAT32), 0x2B (FAT12 / 16), Size: 11 Volume label
Offset: 0x52 (FAT32), 0x36 (FAT12 / 16), Size: 8 File system type
Normally, “FAT32” / “FAT16” / “FAT12” is written.
Offset: 0x1FE, Size: 2 Magic number
0x55AA is written.
[0074]
[4-3. FSINFO (file descriptor)]
FAT32 has an area called FSINFO in logical sector number 1. In FAT12 / 16, in order to calculate the free capacity, all FATs must be read and the number of unused clusters must be counted. In FAT32, the free capacity calculation speed is improved by writing the number of free clusters in this FSINFO. is doing. The actual FSINFO is as follows.
[0075]
[Table 5]

Offset: 0x1E4, Size: 4 File system signature
Fixed to 0x61417272 (rrAa).
Offset: 0x1E8, Size: 4 Number of free clusters
When no free cluster is calculated, 0xFFFFFFFF is written.
Offset: 0x1EC, Size: 4 Last write cluster number
Offset: 0x1F0, Size: 6 Reserved area
Offset: 0x1FE, Size: 2 Magic number
0x55AA is written.
[0076]
[4-4. FAT region (FAT-1 and FAT-2)]
The FAT area is an area where the FAT entries are arranged in the order of the corresponding clusters. Each FAT entry has a one-to-one correspondence with the cluster. By referring to the FAT entry, it is possible to know the state of the corresponding cluster (in use, empty, etc.). The actual FAT area is shown below.
[0077]
[Table 6]
[00000000] F8 FF FF 0F FF FF FF 7F FF FF FF 0F FF FF FF 0F |
[00000010] 06 00 00 00 FF FF FF 0F FF FF FF 0F FF FF FF 0F |
[00000020] FF FF FF 0F 77 00 00 00 0B 00 00 00 FF FF FF 0F |
[00000030] 12 0F 00 00 FF FF FF 0F FF FF FF 0F FF FF FF 0F |
[00000040] FF FF FF 0F FF FF FF 0F 6E 06 00 00 FF FF FF 0F |
[00000050] FF FF FF 0F FF FF FF 0F FF FF FF 0F FF FF FF 0F |
[0078]
Since the FAT32 cluster is represented by 4 bytes (32 bits), the FAT entries are also read by being delimited by 4 bytes. The above entry of Offset 0x10, Size4 is an entry of cluster number 4, indicating that cluster number 6 continues.
[0079]
The meaning of the FAT entry is as follows.
[Table 7]

[0080]
[4-5. Directory entry]
The directory entry is a place where information on files in the directory is recorded. In the FAT32, the root directory information is recorded in the data area as the normal cluster number 2 as the root directory entry. In FAT12 / 16, an area is secured for the root directory entry at the time of formatting.
[0081]
The subdirectory is secured in the data area. The directory entry is assigned 32 bytes for each file from the top. When there are many directory entries, create a cluster chain and create a continuation in another cluster. The actual directory entry is as follows: In Table 8 below, “0000” in the first four digits of the address is omitted.
[0082]
[Table 8]
[00C0] 42 4F 4F 54 20 20 20 20 49 4E 49 26 18 69 23 92 | BOOT INI
[00D0] 82 2B 90 9B 05 00 01 9A 82 2B C6 D6 C1 00 00 00 |
[00E0] 42 20 00 53 00 65 00 74 00 74 00 0F 00 4A 69 00 | B Set t Ji
[00F0] 6E 00 67 00 73 00 00 00 FF FF 00 00 FF FF FF FF | n g s
[0100] 01 44 00 6F 00 63 00 75 00 6D 00 0F 00 4A 65 00 | D o c u m Je
[0110] 6E 00 74 00 73 00 20 00 61 00 00 00 6E 00 64 00 | n t s a n d
[0120] 44 4F 43 55 4D 45 7E 31 20 20 20 10 00 3D 42 92 | DOCUME ~ 1 = B
[0130] 82 2B 88 2B 00 00 43 92 82 2B E6 50 00 00 00 00 |
Offset: 0x00, Size: 8 File name
Offset: 0x08, Size: 3 extension
The MS-DOS format 8.3 file name is recorded. If there are less than 8 or 3 characters, the rest are filled with spaces (0x20). When the first byte is 0xE5, it indicates that the file has been deleted.
Offset: 0x0B, Size: 1 File attribute
This file attribute is represented by the sum of the following numerical values. However, a long file is indicated only for 0x0F.
[0083]
[Table 9]

Offset: 0x0C, Size: 1 Reserved area
Used in Windows NT as a case flag.
Offset: 0x0D, Size: 1 Creation time (10ms unit)
Offset: 0x0E, Size: 2 Creation time
Offset: 0x10, Size: 2 Creation date
Offset: 0x12, Size: 2 Access date
Offset: 0x14, Size: 2 Upper 2 bytes of the first cluster number of the file
For FAT32.
Offset: 0x16, Size: 2 Update time
Offset: 0x18, Size: 2 Update date
Offset: 0x1A, Size: 2 Lower 2 bytes of the first cluster number of the file
Offset: 0x1C, Size: 4 File size
[0084]
[5. (Logic error check method)
Based on the above assumptions, in order to check a logical error, it is compared whether or not the contents of “FAT-1” and “FAT-2” in the area match each other, or an FAT sector number error is checked. It is possible. In the former, “FAT-1” and “FAT-2” are checked by checking what should be essentially the same, and if they are different, repairing is performed by matching one to the other.
[0085]
In this embodiment, there is an advantage that the presence / absence of a logic error can be easily and reliably checked based on a simple standard of FAT commonality. Further, according to the present embodiment, even if there is a mismatch between a plurality of FATs, there is an advantage that repair can be performed easily and reliably by a simple method of unifying them.
[0086]
In the latter case based on the FAT sector number abnormality, it is checked whether or not the cluster numbers indicated by “FAT-1” and “FAT-2” exceed an abnormal value that cannot be taken, for example, the maximum cluster number. For a logical error, the corresponding cluster number is set as an unused area or a final used area.
[0087]
As described above, the present embodiment has an advantage that the presence or absence of a logical error can be easily and reliably checked based on a simple criterion of whether or not there is an abnormality in the sector number or cluster number in the FAT. In addition, the present embodiment has an advantage that even if the cluster number exceeds the maximum cluster number, it can be easily and reliably repaired by a simple method of making it an unused area or a final used area.
[0088]
As a specific check or repair method, any conventionally known method may be selected. For example, whether the relationship between directory information and file information and "FAT-1" or "FAT-2" is strange. It is also possible to use this check. In this way, there is an advantage that a logical error can be detected and repaired easily and easily based on a simple criterion whether the relationship between the directory or file information and the FAT is normal or abnormal.
[0089]
[6. effect〕
As described above, in this embodiment, the read / write large-capacity external storage means such as a hard disk drive is divided into a plurality of areas, and the logical format of the recording data is abnormal, that is, a logical error such as during writing due to an unexpected power interruption. When the error is detected or the possibility is detected, at least a part of the navigation process can be executed using the data of the other area during the error check or repair to the area, so that the usability is improved.
[0090]
In this embodiment, even if a logical error or its possibility is detected in the main storage area, the road map data for backup is read from the spare storage area during the error check and repair, thereby A certain amount of navigation processing such as display of the position and the surrounding map becomes possible, so that the user can always know the position of the vehicle and the usability is improved.
[0091]
In addition, this embodiment has an advantage that the possibility of a logic error can be easily and reliably detected with a simple configuration using a write flag.
[0092]
In this embodiment, the operation of the repair unit 47 eliminates logical errors automatically by self-healing areas and data without prompting for repairs or requesting special knowledge or measures from the user, and promptly returns to a normal state. There is an advantage that can be restored.
[0093]
[7. Other embodiments]
In addition, this invention is not limited to the said embodiment, Other embodiments which are illustrated next are included. For example, the information storage means is not limited to a hard disk, but may be a DVD-RAM, DVD-RW, various flash memory cards, etc., and the logical format of the drive, the mode of logical errors, the contents of checks and repairs, etc. The above-described embodiment is merely an example, and other items can be freely selected. In the above embodiment, the hard disk drive area is divided into two partitions, and the road map data near the vehicle position is always stored in one partition. However, the storage destination is a nonvolatile memory such as SRAM. But you can.
[0094]
In addition, a certain area may be secured for one partition, and a certain level of road map data may be entered from the beginning in a possible range, for example, all over Japan. In this way, there is no need to always back up road map data in the vicinity of the vehicle position to one partition, and there is an advantage that the system load is reduced. Further, the surrounding map display “or a predetermined process corresponding thereto” can be freely selected, such as guidance for the direction of travel at important points.
[0095]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a navigation device, a method, and a program capable of performing a certain navigation operation such as at least a map display around the host vehicle.
[Brief description of the drawings]
FIG. 1 is a functional block diagram showing a configuration of an embodiment of the present invention.
FIG. 2 is a flowchart showing a processing procedure in the embodiment of the present invention.
FIG. 3 is a conceptual diagram showing an outline of a logical format of a hard disk drive in an embodiment of the present invention.
FIG. 4 is a conceptual diagram showing a basic configuration of a FAT according to an embodiment of the present invention.
[Explanation of symbols]
1… Absolute position / azimuth detector
2 ... Relative bearing detector
3 ... Vehicle speed detector
4 ... Main CPU and its peripheral circuits
M ... Memory group
5 ... ROM
6 ... DRAM
7 ... SRAM
8 ... VRAM
9. User interface part
10 ... Display section
11 ... Input section
12 ... HDD controller
13 ... FM multiplex reception and processing unit
14: Light / beacon reception and processing unit
M ... Memory group
40: Current position detector
41 ... Destination designation part
42: Route setting unit
43 ... Map display section
44. Guidance control unit
45. Management detection unit
46 ... Backup control unit
47 ... Restoration Department

Claims (6)

In a navigation device that performs navigation processing using readable and writable information storage means,
  The information storage means comprises a main storage area for storing data necessary for the navigation processing, and a preliminary storage area for storing only road map data near the position of the traveling vehicle.
  At the start of writing to the information storage means, a flag indicating which area is to be written is set in a predetermined nonvolatile memory, the flag is reset at the end of writing, and the flag is checked at the start of the apparatus Management detection means for determining which area is likely to have a logic error,
  A repair means for repairing a logical error in the main storage area,
  The management detection means includes
  When a write flag is not set in the nonvolatile memory at the time of starting the device, a normal navigation process is performed using the data in the main storage area,
  When a write flag is set in the non-volatile memory at the time of startup of the device, and this flag is related to the main storage area, it is determined that there is a possibility of a logic error in the main storage area, While performing a logical error check of the main storage area, performing navigation processing using road map data near the vehicle position stored in the preliminary storage area,
  The repair means repairs if there is a logic error in the main storage area,
  A navigation characterized in that when the check and repair of a logical error in the main storage area is completed, the management detection means starts using the data in the main storage area and performs normal navigation processing. apparatus. The navigation apparatus according to claim 1 , further comprising notification means for notifying that the restoration by the restoration means is in progress. In a navigation method for performing navigation processing using a readable / writable information storage means,
  The information storage means comprises a main storage area for storing data necessary for the navigation processing, and a preliminary storage area for storing only road map data near the position of the traveling vehicle.
  Computer
  At the start of writing to the information storage means, a flag indicating which area is to be written is set in a predetermined nonvolatile memory, the flag is reset at the end of writing, and the flag is checked at the start of the apparatus A management detection step to determine in which area there is a potential logic error;
  A repair step of repairing if there is a logic error in the main storage area, and
  The management detection step includes
  If a write flag is not set in the non-volatile memory at the time of starting the device, performing a normal navigation process using data in the main storage area;
  When a write flag is set in the non-volatile memory at the time of startup of the device, and this flag is related to the main storage area, it is determined that there is a possibility of a logic error in the main storage area, Checking logical errors in the main storage area and performing navigation processing using road map data near the vehicle position stored in the preliminary storage area;
  And a step of performing normal navigation processing by using the data in the main storage area when the logical error check in the main storage area and the repair in the repair process are completed. How to navigate. The navigation method according to claim 3 , wherein the computer executes a notifying step of notifying that the repair is being performed by the repairing step . In a navigation program for causing a computer to perform navigation processing using readable / writable information storage means,
  The information storage means comprises a main storage area for storing data necessary for the navigation processing, and a preliminary storage area for storing only road map data near the position of the traveling vehicle.
  The program is stored in the computer.
  At the start of writing to the information storage means, a flag indicating which area is to be written is set in a predetermined nonvolatile memory, the flag is reset at the end of writing, and the flag is checked at the start of the apparatus A management detection function to determine which areas are likely to have logic errors
  And a repair function for repairing a logical error in the main storage area, and
  The management detection function is:
  When a write flag is not set in the non-volatile memory at the time of starting the device, a function of performing normal navigation processing using data in the main storage area,
  When a write flag is set in the non-volatile memory at the time of startup of the device, and this flag is related to the main storage area, it is determined that there is a possibility of a logic error in the main storage area, A function of performing a navigation process using road map data in the vicinity of the vehicle position stored in the preliminary storage area, while checking a logical error in the main storage area;
  A function of starting normal data processing by using data in the main storage area when the logical error check in the main storage area and the repair in the repair process are completed. Navigation program. A computer, a navigation program according to claim 5, characterized in that to realize the notification function of notifying that it is being repaired in the repair function.

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