JP4703886B2

JP4703886B2 - Navigation device

Info

Publication number: JP4703886B2
Application number: JP2001131232A
Authority: JP
Inventors: 悟中江
Original assignee: Denso Ten Ltd
Current assignee: Denso Ten Ltd
Priority date: 2001-04-27
Filing date: 2001-04-27
Publication date: 2011-06-15
Anticipated expiration: 2021-04-27
Also published as: JP2002323551A

Description

【０００１】
【発明の属する技術分野】
本発明は、車両の走行案内を行うナビゲーション装置に係り、特に、ＧＰＳ航法により検出されたデータの信頼性判断に関する。
【０００２】
【従来の技術】
図８はナビゲーション装置の構成を示すブロック図である。以下、図に従って説明する。
【０００３】
１１は人工衛星（ＧＰＳ衛星）からの電波を受信して、その信号から位置情報等を算出するＧＰＳ受信機である。１２は車両の進行方向を検出するジャイロセンサ等の方位センサである。１３は車両の走行距離を検出する距離センサで、自動車の速度計の信号等が用いられる。１４は地図情報が記憶されたＣＤ−ＲＯＭまたはＤＶＤ（ＤｉｇｉｔａｌＶｅｓａｔｉｌｅＤｉｓｋ）及びその読取装置等からなる地図データベースである。２はＧＰＳ受信機１１からの位置情報、方位センサ１２の方位データ、距離センサ１３の走行距離データ、地図データベース１４の地図情報を基に自車位置を特定する処理、登録（入力）された目的地までの走行経路を探索する処理、探索された経路に沿って車両を案内する処理、所定の条件に基いて施設等を検索する処理、検出データの信頼性判断等を行うマイクロコンピュータ及び付随するＲＡＭ、ＲＯＭ等で構成された制御部である。３１は目的地入力、登録等を行うための操作スイッチ等からなる入力部である。４１は制御部２からの信号に基いて案内のための地図（道路）を表示する液晶表示パネル及び駆動回路等で構成された表示部である。４２は制御部２からの指示に基いて案内のための音声や、入力された文字に対応する音声を合成し、スピーカ等で音声案内を行うための音声出力部である。
【０００４】
車両の走行案内を行うナビゲーション装置では、自車位置を検出するに当り、方位センサ１２と距離センサ１３を用いて各時点における移動ベクトル（方位と距離（または速度））を積算して現在位置を算出する自立航法と、ＧＰＳ衛星からの電波をＧＰＳ受信機１１で受信して直接現在位置、方位、速度を検出するＧＰＳ航法の２航法がある。
【０００５】
自立航法では、方位センサ１２で車両の進行方向を距離センサ１３で移動距離を検出して、原点位置となる出発点を基準にして各時点における移動ベクトルを積算して現在位置を算出する。また、算出した位置を地図データベース１４の道路位置と照合（マップマッチング）して方位や位置を修正している。しかし、方位センサ１２はバイアス電圧の変動等により検出方位に誤差が生じるので、各時点における移動ベクトルを積算すると誤差が累積されて、時間と共に算出した現在位置が真の現在位置から徐々にずれが大きくなる。
【０００６】
一方、ＧＰＳ航法では、３つ以上のＧＰＳ衛星からの電波をＧＰＳ受信機１１で受信して、それぞれの衛星の位置と受信するまでの時間から自車の位置を直接演算するものである。しかし、受信するＧＰＳ衛星の配置や受信電波の状態、例えばＧＰＳ衛星が見通せる位置で直接ＧＰＳ衛星の電波を受信する場合は検出データの信頼性は高いが、ＧＰＳ衛星の電波をビル等による反射波として受信する場合は信頼性に欠け、突然真の位置から大きくずれることがある。また、トンネルやビル街を走行中にはＧＰＳ衛星からの電波が受信できず位置等の検出ができない。
【０００７】
そこで、両航法の欠点を補うために走行中に、自立航法で算出した方位や位置をＧＰＳ衛星で検出した方位や位置で補正する方法が行われている。この時、ＧＰＳ航法の信頼性をＧＰＳデータ内に含まれる信頼性データ（ＤＯＰ）で判断し、ＤＯＰが信頼性が低いと判断すると、ＧＰＳデータ（ＧＰＳ航法により検出された位置データ、方位データ、速度データ等で、以下ＧＰＳデータと称する）による方位や位置補正を行わないようにしている。
【０００８】
【発明が解決しようとする課題】
従来のナビゲーション装置においては、ＧＰＳ航法により検出されたＧＰＳデータの信頼性を判断する方法として、受信するＧＰＳ衛星の配置やＧＰＳデータ内の信頼性データ（ＤＯＰ）を使用して、ＤＯＰデータが信頼性が低いと判断すると、検出されたＧＰＳデータを使用して自立航法で検出した方位や位置の補正を行わないようにしている。
【０００９】
しかし、ＤＯＰデータは概ね信頼性を正しく表しているが、その算出方法が可視衛星の配置に大きく影響されるため、天空の視界が開けていない場所ではＧＰＳデータの信頼性を実際よりも低いと判断する場合がある。そのため、市街地などのように天空があまり開けていない場所では、ＧＰＳデータは正しい位置・方位を示しているのに、ＤＯＰデータが「信頼性が低い」となっている場合がある。このような状態が続くと、ＧＰＳデータが有効に利用されず自立航法で検出した方位や位置が補正されない状態が長時間続くという問題がある。
【００１０】
本発明は、自立航法で検出した現在位置、方位をＧＰＳデータで補正するに当り、ＧＰＳ航法により検出したデータの信頼性の判断が適切に行えるナビゲーション装置を提供することを目的とする。
【００１１】
【課題を解決するための手段】
上記目的を達成するために本発明は、旋回角度センサと距離センサにより検出した自立移動ベクトルを積算して自車位置を検出する自立航法手段と、ＧＰＳ衛星からの電波を受信して自車位置を検出するＧＰＳ航法手段を備えたナビゲーション装置において、前記ＧＰＳ航法手段により検出されたデータに基いて、車両の進行方向と速度を示すＧＰＳ移動ベクトルを算出するＧＰＳベクトル算出手段と、前記自立航法手段により検出されたデータに基づき車両の進行方向と速度を示す自立移動ベクトルを算出する自立ベクトル算出手段と、前記ＧＰＳベクトル算出手段により算出された複数の計測時点におけるＧＰＳ移動ベクトルの差分を示すＧＰＳ差分データを算出するＧＰＳ差分算出手段と、前記自立ベクトル算出手段により算出された前記複数の計測時点に対応する自立移動ベクトルの差分を示す自立差分データを算出する自立差分算出手段と、前記ＧＰＳ差分算出手段によって算出されたＧＰＳ差分データと前記自立差分算出手段によって算出された自立差分データの差を示す差データを算出する差算出手段と、前記差算出手段により算出された差データが所定値以下の場合に前記ＧＰＳ航法手段により検出されたデータの信頼性が高いと判断する判断手段を備えたことを特徴とするものである。
【００１２】
また、旋回角度センサと距離センサにより検出した自立移動ベクトルを積算して自車位置を検出する自立航法手段と、ＧＰＳ衛星からの電波を受信して自車位置を検出するＧＰＳ航法手段を備えたナビゲーション装置において、前記ＧＰＳ航法手段により検出されたデータに基いて、車両の進行方向と速度を示すＧＰＳ移動ベクトルを算出するＧＰＳベクトル算出手段と、前記自立航法手段により検出されたデータに基づき車両の進行方向と速度を示す自立移動ベクトルを算出する自立ベクトル算出手段と、前記ＧＰＳベクトル算出手段により算出された複数の計測時点におけるＧＰＳ移動ベクトルと前記自立ベクトル算出手段により算出された前記複数の計測時点に対応する自立移動ベクトルの差分を示す複数の差分データを算出する差分算出手段と、前記差分算出手段によって算出された複数の差分データの差を示す差データを算出する差算出手段と、前記差算出手段により算出された差データに基いて前記ＧＰＳ航法手段により検出されたデータの信頼性を判断する判断手段とを備え、前記判断手段は、前記ＧＰＳ移動ベクトルと前記自立移動ベクトルがそれぞれｎ個集積された時点で前記ＧＰＳ航法手段により検出されたデータの信頼性を判断し、前記集積される移動ベクトル数ｎは、前記ＧＰＳ衛星からの電波の受信状態により変動されることを特徴とするものである。
また、旋回角度センサと距離センサにより検出した自立移動ベクトルを積算して自車位置を検出する自立航法手段と、ＧＰＳ衛星からの電波を受信して自車位置を検出するＧＰＳ航法手段を備えたナビゲーション装置において、前記ＧＰＳ航法手段により検出されたデータに基いて、車両の進行方向と速度を示すＧＰＳ移動ベクトルを算出するＧＰＳベクトル算出手段と、前記自立航法手段により検出されたデータに基づき車両の進行方向と速度を示す自立移動ベクトルを算出する自立ベクトル算出手段と、前記ＧＰＳベクトル算出手段により算出された複数の計測時点におけるＧＰＳ移動ベクトルと前記自立ベクトル算出手段により算出された前記複数の計測時点に対応する自立移動ベクトルの差分を示す複数の差分データを算出する差分算出手段と、前記差分算出手段によって算出された複数の差分データの差を示す差データを算出する差算出手段と、前記差算出手段により算出された差データに基いて前記ＧＰＳ航法手段により検出されたデータの信頼性を判断する判断手段とを備え、前記判断手段は、前記ＧＰＳ移動ベクトルと前記自立移動ベクトルがそれぞれｎ個集積された時点で前記ＧＰＳ航法手段により検出されたデータの信頼性を判断し、前記集積される移動ベクトル数ｎは、前記ＧＰＳ移動ベクトルが異常である頻度により変動されることを特徴とするものである。
また、前記ＧＰＳ差分算出手段は、連続する２つのＧＰＳ移動ベクトルの曲がり角度を差分データとして算出し、前記自立差分算出手段は、連続する２つの自立移動ベクトルの曲がり角度を差分データとして算出することを特徴とするものである。
【００１３】
また、前記ＧＰＳベクトル算出手段は、ＧＰＳ航法手段が検出した複数の位置データに基づきＧＰＳベクトルを算出することを特徴とするものである。
【００１４】
また、前記ＧＰＳベクトル算出手段は、ＧＰＳ航法手段が検出したドップラー効果によるＧＰＳ衛星からの電波の変化に基づきＧＰＳベクトルを算出することを特徴とするものである。
【００１５】
また、前記判断手段は、前記ＧＰＳ移動ベクトルに異常がある時は、該異常のあるＧＰＳ移動ベクトルを除いて前記ＧＰＳ航法手段により検出されたデータの信頼性を判断することを特徴とするものである。
【００１６】
また、前記判断手段は、前記ＧＰＳ移動ベクトルと前記自立移動ベクトルがそれぞれｎ個集積された時点で前記ＧＰＳ航法手段により検出されたデータの信頼性を判断することを特徴とするものである。
【００１７】
また、前記集積される移動ベクトル数ｎは、前記ＧＰＳ衛星からの電波の受信状態により変動されることを特徴とするものである。
【００１８】
また、前記集積される移動ベクトル数ｎは、前記ＧＰＳ移動ベクトルが異常である頻度により変動されることを特徴とするものである。
【００１９】
また、車両の方位の変化量を検出する方位変化検出手段と、前記方位変化検出手段により検出された方位の変化量の絶対値を積算する積算手段を備え、前記判断手段は、前記積算手段により積算された方位の変化量の絶対値の積算量が所定値を超えた時に、前記ＧＰＳ航法手段により検出されたデータの信頼性を判断することを特徴とするものである。
【００２０】
また、前記判断手段により前記ＧＰＳ航法手段により検出されたデータの信頼性が高いと判断された時に、前記ＧＰＳ航法手段により検出されたデータを使用して前記自立航法手段において検出された方位を補正する方位補正手段を備えたことを特徴とするものである。
【００２１】
また、前記判断手段により前記ＧＰＳ航法手段により検出されたデータの信頼性が高いと判断された時に、前記ＧＰＳ航法手段により検出されたデータを使用して前記自立航法手段において検出された自車位置を補正する自車位置補正手段を備えたことを特徴とするものである。
【００２２】
【発明の実施の形態】
図１はＧＰＳ航法により検出した方位・速度データに基づく移動ベクトルの説明図で、（ａ）は移動ベクトルの説明図、（ｂ）はベクトル差分１の説明図、（ｃ）はベクトル差分２の説明図である。図２は多データ集積処理による信頼性判断の説明図である。図３は異常データ無効処理による信頼性判断の説明図である。図４はＧＰＳ航法により検出したＧＰＳ位置データに基づく移動ベクトルの説明図で、（ａ）は移動ベクトルの説明図、（ｂ）はベクトル差分１の説明図、（ｃ）はベクトル差分２の説明図である。以下、図を用いて説明する。尚、装置の構成は従来のナビゲーション装置と同じで、制御部２の処理方法が異なるのみであるので説明は省略する。
【００２３】
先ず、信頼性判断の方法について図１を用いて説明する。矢印Ｃ１はＧＰＳ航法により一定時間毎に（例えば、１秒毎）検出した方位データと速度データを基に算出したＧＰＳ移動ベクトルＣ１、矢印Ｃ２はＧＰＳ航法により一定時間毎に（例えば、１秒毎）検出した方位データと速度データを基に算出したＧＰＳ移動ベクトルＣ２である。
【００２４】
矢印Ｄ１は自立航法により前回のＧＰＳ受信時（本来は両航法は別々の検出装置で異なる周期で方位・速度を検出しているが、両データを比較するためにＧＰＳ移動ベクトルとの検出タイミングの同期合わせ、あるいは検出されたデータで同時点と見做して問題ない時点のデータの組合せ処理を行う）に検出した方位データと速度データを基に算出した自立移動ベクトルＤ１、矢印Ｄ２は自立航法により今回のＧＰＳ受信時に検出した方位データと速度データを基に算出した自立移動ベクトルＤ２である。
【００２５】
図１（ａ）において、ＧＰＳ移動ベクトルＣ１、Ｃ２と自立移動ベクトルＤ１、Ｄ２のベクトル（矢印の方向、大きさ）は大きくずれている。この主な原因は方位センサの温度変化によるオフセット電圧のシフトである。だからと言って、ＧＰＳ航法による検出結果が正しいと判断して補正することはできない。その理由はＧＰＳ航法にも受信するＧＰＳ衛星の配置や受信電波の状態、例えばＧＰＳ衛星が見通せる位置で直接ＧＰＳ衛星の電波を受信する場合は検出位置の信頼性は高いが、ＧＰＳ衛星の電波をビル等による反射波として受信する場合は信頼性に欠け、突然真の位置から大きくずれることがあるためである。
【００２６】
次に、信頼性判断方法について述べる。ＧＰＳ移動ベクトルＣ１、Ｃ２と自立移動ベクトルＤ１、Ｄ２の対応する各ベクトル差分を比較する（図１（ｂ）、（ｃ）参照）。つまり、ＧＰＳ移動ベクトルＣ１と自立移動ベクトルＤ１のベクトル差分Ｑ１を求める。また、ＧＰＳ移動ベクトルＣ２と自立移動ベクトルＤ２のベクトル差分Ｑ２を求める。そして、ベクトル差分Ｑ１とベクトル差分Ｑ２の差Ｙ１を求める。自立航法では、各時刻において検出した方位と速度からなる移動ベクトルを積算して現在位置を算出するが、この時ジャイロセンサの特性上、方位や距離の誤差が累積され、時間と共に算出した現在位置が真の現在位置から徐々にずれが生ずる。しかし、ＧＰＳデータのように前回の算出位置から急激に変化するようなことは起こらない。このことは、この短時間内に自立航法により測定した相対位置は正しいと言える。従って、この差Ｙ１が小さい時はＧＰＳ航法で測定した相対位置にも異常がなく位置、方位、速度検出の信頼性が高いと言える。別の判断方法をすれば、差Ｙ１が小さいと、自立航法で測定したベクトル軌跡（Ｄ１〜Ｄ２）をＧＰＳ航法で測定したベクトル軌跡（Ｃ１〜Ｃ２）の方向に重なるように回転すると概略一致する。換言すれば、ＧＰＳ移動ベクトルＣ１とＧＰＳ移動ベクトルＣ２の曲がり角度と、自立移動ベクトルＤ１と自立移動ベクトルＤ２の曲がり角度の差（及び絶対値の差、つまりＹ１に相当する）を判断の対象にしている（角度の差だけでの判断も可）。この差はＧＰＳ移動ベクトルＣ１、Ｃ２と自立移動ベクトルＤ１、Ｄ２の方向とは全く関係くＧＰＳデータの信頼性が高ければ小さくなる。
【００２７】
尚、本実施の形態においては、ＧＰＳ移動ベクトルＣ１と自立移動ベクトルＤ１のベクトル差分Ｑ１を算出し、またＧＰＳ移動ベクトルＣ２と自立移動ベクトルＤ２のベクトル差分Ｑ２を算出した後に、ベクトル差分Ｑ１とベクトル差分Ｑ２の差を算出しているが、別の方法として、ＧＰＳ移動ベクトルＣ１とＧＰＳ移動ベクトルＣ２のベクトル差分Ｆ１を算出し、また自立移動ベクトルＤ１と自立移動ベクトルＤ２のベクトル差分Ｇ１を算出した後に、ベクトル差分Ｆ１とベクトル差分Ｇ１の差を算出するようにしてもよい。
【００２８】
上記の信頼性判断方法は２つの移動ベクトルを用いて説明したが、図２に示すように多数のデータ（移動ベクトル）を用いると判断の信頼性が向上する。図２において、Ｃ１、Ｃ２、Ｃ３、Ｃ４、Ｃ５はＧＰＳ移動ベクトルＣ１、Ｃ２、Ｃ３、Ｃ４、Ｃ５であり、Ｄ１、Ｄ２、Ｄ３、Ｄ４、Ｄ５は自立移動ベクトルＤ１、Ｄ２、Ｄ３、Ｄ４、Ｄ５である。また、両移動ベクトルからベクトル差分Ｑ１、Ｑ２、Ｑ３、Ｑ４、Ｑ５を求め、そのベクトル差分の差Ｙ１＝（Ｑ１〜Ｑ２）、Ｙ２＝（Ｑ２〜Ｑ３）、Ｙ３＝（Ｑ３〜Ｑ４）、Ｙ４＝（Ｑ４〜Ｑ５）を求める。そして、全てのベクトル差分の差（Ｙ１、Ｙ２、Ｙ３、Ｙ４）が所定値以下にある時はＧＰＳデータは信頼性が高いと判断する。図２では、５つの移動ベクトルについて説明しているが、この場合、新しいデータが１つ取得されると（１秒後）、古いデータを１つ削除するようにして、常にデータ数が一定（５つ）になるように順次１つずつデータを更新する。当然、データ数ｎを多くすると判断の信頼性は向上するが、データ数ｎが多くなると処理が面倒になり、またデータの修正速度が遅くなるので、直近のＧＰＳデータの信頼性に基いてデータ数ｎを変更するようにしてもよい。例えば、直近のＧＰＳデータの信頼性が高ければデータ数ｎを少なくし、直近のＧＰＳデータの信頼性が低ければデータ数ｎを多く（例えば、６〜１０個）なるように変更する。ＧＰＳデータの信頼性はＧＰＳデータが連続して受信できた数、ＤＯＰデータ、受信できたＧＰＳ衛星数を基に判断する。
【００２９】
また、多数のデータ（移動ベクトル）を用いて判断する場合に、明らかに異常と思われるデータ（移動ベクトル）を比較対象から除去してから判断する必要がある。例えば図３において、ＧＰＳデータのＣＺ点が異常点と判断されると、この点を除き、両端を結ぶＧＰＳ移動ベクトルＣ２３を使用する。この時、対応する自立移動ベクトルも同様に削除し自立移動ベクトルＤ２３を採用する。無効データ（異常点）であるか否かはＧＰＳ衛星からの電波の受信状態の良否、ＤＯＰデータ、車速を基に判断する。
【００３０】
尚、ここでは、ＧＰＳ航法で検出したＧＰＳ方位データ・ＧＰＳ速度データを基に算出したＧＰＳ移動ベクトルＣを使用した場合について述べたが、ＧＰＳ航法で検出したＧＰＳ位置データを基に算出したＧＰＳ移動ベクトルＡを使用してＧＰＳデータの信頼性を判断することも可能である。この場合、図４に示すように、ＧＰＳ移動ベクトルＡ１は前々回のＧＰＳ受信時の位置データと前回のＧＰＳ受信時の位置データから算出されたＧＰＳ移動ベクトル、ＧＰＳ移動ベクトルＡ２は前回のＧＰＳ受信時の位置データと今回のＧＰＳ受信時の位置データから算出されたＧＰＳ移動ベクトルとなる。また、自立移動ベクトルＢ１は前々回のＧＰＳ受信時から前回のＧＰＳ受信時までの自立移動ベクトル、自立移動ベクトルＢ２は前回のＧＰＳ受信時から今回のＧＰＳ受信時までの自立移動ベクトルとなる。その他、ベクトル差分Ｐ１、Ｐ２の求め方、差分の差の求め方、多データ集積処理による信頼性判断、異常データ無効処理による信頼性判断は図１〜図３の説明と概略同じであるので詳細は省略する。
【００３１】
次に、ＧＰＳ検出データの信頼性判断の具体的な処理方法についてフローチャートを使用して説明する。図５は本発明の一実施の形態に係るナビゲーション装置の制御部２の行う信頼性判断処理のフローチャートである。図６はＧＰＳデータ異常時の移動ベクトルを示す図である。図７は自立移動ベクトルの変動の説明図である。以下、図に従って説明する。尚、この処理はナビゲーション装置が稼働中は繰り返し実行される。
【００３２】
ステップＳ１では、ＧＰＳ受信頻度により参照数ｎを変更してステップＳ２に移る。つまり、ＧＰＳ航法による検出データ（移動ベクトルデータ）と自立航法による検出データ（移動ベクトルデータ）の比較すべきデータ数ｎを過去のＧＰＳ電波の受信状態によって変化させる。ＧＰＳ電波の受信状態がよければＧＰＳデータの信頼性が高いと判断して比較すべきデータ数ｎを小さく、受信状態が悪ければｎを大きくする。比較すべきデータ数を少なくすると、後述する自立航法の方位、位置補正が早期に行える利点がある。受信状態はＧＰＳ衛星から連続して受信できたデータ数、ＤＯＰデータ、受信できた衛星の数等から判断する。このフローチャートは繰り返し実行されているが、電源を投入した直後等過去の受信状態が判らず使用すべきデータ数ｎが決められない場合は、暫定的に所定の値（例えば、ｎ＝８）を使用すればよい。尚、本実施の形態のナビゲーション装置における処理の以下のステップでは、受信状態により比較するデータ数ｎを変えるが、ｎ＝８（ＧＰＳ航法により１秒毎に検出した８個のＧＰＳ移動ベクトル、自立航法により１秒毎に検出した８個の自立移動ベクトルが集まった時点で信頼性判断を行う）の場合を例に説明する。
【００３３】
ステップＳ２では、ＧＰＳ航法により検出したデータ（位置データ、方位データ、速度データ、ＤＯＰデータ）と自立航法により検出したデータ（旋回角度データ、移動距離データ）を読み込み、同期合わせ（同時点で検出したデータとして扱えるデータ、例えば、最も接近した検出時点のデータを同時点の検出データとする）を行ってステップＳ３に移る。つまり、比較すべき両航法により検出し、制御部２内のメモリ（ＲＡＭ）に保存されているデータをメモリから読み出す。ＧＰＳデータはＧＰＳ航法により検出した位置データ、方位データ、速度データ、ＤＯＰデータ等であり、旋回角度データは方位センサ（ジャイロセンサ）１２により検出したデータ、移動距離データは距離センサ１３により検出したデータである。次に、両航法により検出され、読み込んだデータの同期合わせを行う。例えば、１秒間隔でＧＰＳ航法で検出した１番目のデータと自立航法で検出した１番目のデータを対応させ、ＧＰＳ航法で検出した２番目のデータと自立航法で検出した２番目のデータを対応させる。以下、同様にして必要なデータ数ｎ（ここでは８個）のデータを対応させる。この同期合わせは両航法によるデータのサンプリング周期（検出周期）、あるいはタイミングが異なっていた場合に必要で、両航法とも同一周期（で且つ、同一タイミング）でサンプリングしておれば不要である。
【００３４】
ステップＳ３では、ＧＰＳデータが有効か否かを判断してＧＰＳデータが有効であればステップＳ４に移り、有効でなければ処理を終える。つまり、ＧＰＳ衛星の電波の受信が可能な場合を有効、トンネルや地下駐車場等で電波が受信不可能な場合を無効と判断する。この判断はＧＰＳ電波の受信状態の概略を判断するもので、検出された個々のデータの信頼性を判断するものではない。また、ＧＰＳ航法では単位時間の移動量が小さい場合も検出精度が悪いので、自立航法における距離センサ１３により検出された車速が低い場合も無効と判断する方法も有効である。
【００３５】
ステップＳ４では、ＧＰＳ方位データ、速度データからＧＰＳ移動ベクトルＣを算出してステップＳ５に移る。つまり、ＧＰＳ航法で検出した８個のデータについて、１番目のＧＰＳ方位データ、速度データから図２で説明したように第１のＧＰＳ移動ベクトルＣ１を算出する。また、２番目のＧＰＳ方位データ、速度データから第２のＧＰＳ移動ベクトルＣ２を算出する。以下同様にして３番目〜８番目のＧＰＳ方位データ、速度データから第３のＧＰＳ移動ベクトルＣ３〜第８のＧＰＳ移動ベクトルＣ８を算出する。
【００３６】
ステップＳ５では、自立航法により検出した旋回角度データ、速度データから自立移動ベクトルＤを算出してステップＳ６に移る。つまり、自立航法で検出した８個のデータについて、１番目の旋回角度データ、速度データから図２で説明したように第１の自立移動ベクトルＤ１を算出する。また、２番目の旋回角度データ、速度データから第２の自立移動ベクトルＤ２を算出する。以下同様にして３番目〜８番目の旋回角度データ、速度データから第３の自立移動ベクトルＤ３〜第８の自立移動ベクトルＤ８を算出する。
【００３７】
ステップＳ６では、自立移動ベクトルの変動（絶対値の積算）が所定値以上であるか否かを判断して変動が所定値以上であればステップＳ７に移り、変動が所定値以上でなければステップＳ１１に移る。この判断は図６に示すように、ＧＰＳ電波の不要反射波の受信等によるＧＰＳ航法の精度低下の場合、直線区間ではＧＰＳ航法により異常な車両位置を出力しても、ＧＰＳ航法から算出したＧＰＳ移動ベクトルと自立移動ベクトルが略直線（各ベクトルＣ１、Ｃ２が略同一方向、また各ベクトルＤ１、Ｄ２が略同一方向）となる場合が比較的多くあり、両者が一致したようになる。このような場合には、信頼性判断の説明図（図１）で述べたように、両者が直線区間であればＧＰＳ航法で検出した車両位置が異常であっても正しいと判断してしまう恐れがある。そこで、このように各ベクトルの変動（ベクトルＤ１とベクトルＤ２のように次のベクトルとの差（絶対値））が少ない時は、この区間のデータは判断には使用しないようにしている。つまり、自立移動ベクトルＤ１と自立移動ベクトルＤ２の差（絶対値）、自立移動ベクトルＤ２と自立移動ベクトルＤ３の差（絶対値）、以下同様にして、自立移動ベクトルＤ７と自立移動ベクトルＤ８の差（絶対値）を求め積算する。そして、この積算値が所定値以上であるか否かを判断する。図７では、ベクトルの変動の代わりに、ベクトル変動角θ１、θ２、θ３、θ４（角度はいずれも絶対値）を使用しており、この場合、積算値Σθ＝θ１＋θ２＋θ３＋θ４・・・・＋θ７で示され、この積算値Σθが所定値以上であるか否かで判断する。尚、所定値未満と判断された場合は処理を終えるが、このフローチャートは繰り返し実行されるので、次回の処理（ステップＳ６では、新しいデータが１つ追加され、古いデータが１つ削除されるている）で所定値以上となればステップＳ７に移る。また、積算値Σθが所定値未満で処理を終えた時は、次の処理のステップＳ１でデータ数ｎを１つ増やすようにしてもよい。
【００３８】
ステップＳ７では、以前の移動ベクトルデータがｎ個以上存在するか否かを判断して移動ベクトルのデータ数がｎ個以上存在すればステップＳ８に移り、ｎ個未満であればステップＳ１１に移る。つまり、ステップＳ１において両航法により比較するベクトル数（ｎ）を設定したが、このデータ数がｎ個以上なければ比較する場合の信頼性が悪いので所定のデータ数（ｎ＝８）が揃うまで両航法による一致度の判断は保留する。
【００３９】
ステップＳ８では、ＧＰＳ移動ベクトルＣ１〜Ｃ８、自立移動ベクトルＤ１〜Ｄ８の各ベクトル差分を比較してステップＳ９に移る。つまり、図１で説明したように、ＧＰＳ移動ベクトルＣ１と自立移動ベクトルＤ１のベクトル差分Ｑ１を求める。次に、ＧＰＳ移動ベクトルＣ２と自立移動ベクトルＤ２のベクトル差分Ｑ２を求める。また、ＧＰＳ移動ベクトルＣ３と自立移動ベクトルＤ３のベクトル差分Ｑ３を求める。以下同様にして、ＧＰＳ移動ベクトルＣ８と自立移動ベクトルＤ８のベクトル差分Ｑ８まで、８個のベクトル差分を求める。そして、ベクトル差分Ｑ１とベクトル差分Ｑ２の差Ｙ１を求める。以下同様にして、ベクトル差分Ｑ２とベクトル差分Ｑ３の差Ｙ２、以下同様にしてベクトル差分Ｑ７とベクトル差分Ｑ８の差Ｙ７まで７個のベクトル差分の差のデータ（Ｙ１〜Ｙ７）を算出する。
【００４０】
ステップＳ９では、ＧＰＳデータが使用可能か否かを判断して使用可能であればステップＳ１０に移り、使用可能でなければステップＳ１１に移る。つまり、算出された７個のベクトル差分の差のデータ（Ｙ１〜Ｙ７）がいずれも所定値以下であるか否かで判断する。これは各移動ベクトルが同じように変化している（角度変化及び距離）か否かを判断しており、ＧＰＳ移動ベクトルＣ１〜Ｃ８と自立移動ベクトルＤ１〜Ｄ８を回転させて重ね合わせた場合の一致度を判断していることになる。
【００４１】
ステップＳ１０では、位置補正、方位補正を実施してステップＳ１１に移る。つまり、ＧＰＳデータの信頼性が高いと判断されたので、自立航法で検出した位置、方位をＧＰＳデータに一致させるように補正する。補正後の位置データ、つまりナビゲーション装置で使用する位置データは制御部２内のＲＡＭの所定アドレスに記憶されており、この記憶された位置データをＧＰＳデータに基づき補正することとなる。尚、補正の方法については一般に行われている方法と同じであり、詳細は説明を省略する。
【００４２】
ステップＳ１１では、各ベクトルデータを保存して処理を終わる（繰り返し処理されるのでステップＳ１に戻る）。つまり、次の処理で移動ベクトルデータの比較を行うために、算出したベクトルデータを保存する。
【００４３】
尚、本実施の形態では、ステップＳ５においてＧＰＳ方位データ、ＧＰＳ速度データからＧＰＳ移動ベクトルＣを算出する場合について述べたが、このステップＳ５において、ＧＰＳ位置データからＧＰＳ移動ベクトルＡを算出するようにしてもよい（算出方法の詳細は図４で説明済）。この場合は８個のＧＰＳ移動ベクトルＡ１〜Ａ８を求めるために９個の位置データ（×印の位置）が必要となる。また、対応する自立移動ベクトルはＢ１〜Ｂ８となる。
【００４４】
以上のように本実施の形態では、ＧＰＳ移動ベクトルと自立移動ベクトルを直接比較するのではなく、連続する両移動ベクトルの差分の変化でＧＰＳデータの信頼性を判断しており、方位センサのシフトによる影響が除かれてＧＰＳデータの信頼性が適正に判断できる。
【００４５】
【発明の効果】
以上説明したように、本発明では、自立航法で検出した現在位置、方位をＧＰＳデータで補正するに当り、ＧＰＳ航法により検出したデータの信頼性の判断が適切に行えるナビゲーション装置が提供できる。
【図面の簡単な説明】
【図１】ＧＰＳ航法により検出した方位・速度データに基づく移動ベクトルの説明図である。
【図２】多データ集積処理による信頼性判断の説明図である。
【図３】異常データ無効処理による信頼性判断の説明図である。
【図４】ＧＰＳ航法により検出した位置データに基づく移動ベクトルの説明図である。
【図５】本発明の一実施の形態に係るナビゲーション装置の制御部２の行う信頼性判断処理のフローチャートである。
【図６】ＧＰＳデータ異常時の移動ベクトルを示す図である。
【図７】自立移動ベクトルの変動の説明図である。
【図８】ナビゲーション装置の構成を示すブロック図である。
【符号の説明】
１１・・・・ＧＰＳ受信機、２・・・・・制御部、
１２・・・・方位センサ、３１・・・・入力部、
１３・・・・距離センサ、４１・・・・表示部、
１４・・・・地図データベース、４２・・・・音声出力部。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a navigation apparatus that provides vehicle travel guidance, and more particularly, to reliability determination of data detected by GPS navigation.
[0002]
[Prior art]
FIG. 8 is a block diagram showing the configuration of the navigation device. Hereinafter, it demonstrates according to a figure.
[0003]
A GPS receiver 11 receives radio waves from an artificial satellite (GPS satellite) and calculates position information and the like from the signal. Reference numeral 12 denotes an orientation sensor such as a gyro sensor that detects the traveling direction of the vehicle. Reference numeral 13 denotes a distance sensor that detects the travel distance of the vehicle, and uses a signal from an automobile speedometer or the like. Reference numeral 14 denotes a map database including a CD-ROM or DVD (Digital Vesatile Disk) storing map information and a reading device thereof. 2 is a process for specifying the vehicle position based on the position information from the GPS receiver 11, the direction data of the direction sensor 12, the travel distance data of the distance sensor 13, and the map information of the map database 14, and the registered (input) purpose. A microcomputer for performing a process of searching for a travel route to the ground, a process of guiding a vehicle along the searched route, a process of searching for a facility based on a predetermined condition, a reliability determination of detection data, and the like It is a control part comprised by RAM, ROM, etc. Reference numeral 31 denotes an input unit including operation switches for performing destination input, registration, and the like. A display unit 41 includes a liquid crystal display panel that displays a map (road) for guidance based on a signal from the control unit 2 and a drive circuit. Reference numeral 42 denotes a voice output unit for synthesizing a voice for guidance based on an instruction from the control unit 2 or a voice corresponding to an input character and performing voice guidance using a speaker or the like.
[0004]
In a navigation apparatus that provides vehicle travel guidance, when detecting the position of the vehicle, the current position is obtained by integrating movement vectors (direction and distance (or speed)) at each time point using the direction sensor 12 and the distance sensor 13. There are two types of navigation: self-contained navigation to be calculated and GPS navigation in which radio waves from GPS satellites are received by the GPS receiver 11 to directly detect the current position, direction, and speed.
[0005]
In the self-contained navigation, the traveling direction of the vehicle is detected by the direction sensor 12 and the moving distance is detected by the distance sensor 13, and the current position is calculated by integrating the moving vectors at each time point with the starting point as the origin position as a reference. The calculated position is collated with the road position in the map database 14 (map matching) to correct the azimuth and position. However, since the direction sensor 12 has an error in the detected direction due to fluctuations in the bias voltage or the like, if the movement vectors at each time point are accumulated, the error is accumulated, and the current position calculated with time gradually shifts from the true current position. growing.
[0006]
On the other hand, in GPS navigation, radio signals from three or more GPS satellites are received by the GPS receiver 11, and the position of the own vehicle is directly calculated from the position of each satellite and the time until reception. However, if the GPS satellite radio waves are received directly at the location of the receiving GPS satellites and the status of the received radio waves, for example, at a position where the GPS satellites can be seen, the detection data is highly reliable. As a result, it is not reliable and may suddenly deviate from the true position. Further, when traveling in a tunnel or a building town, radio waves from GPS satellites cannot be received, and the position and the like cannot be detected.
[0007]
Therefore, in order to compensate for the shortcomings of both navigation methods, a method of correcting the azimuth and position calculated by the self-contained navigation with the azimuth and position detected by the GPS satellite during traveling is being performed. At this time, the reliability of the GPS navigation is determined by the reliability data (DOP) included in the GPS data, and if the DOP is determined to have low reliability, the GPS data (position data, direction data detected by the GPS navigation, The azimuth and position correction based on speed data or the like (hereinafter referred to as GPS data) is not performed.
[0008]
[Problems to be solved by the invention]
In a conventional navigation apparatus, as a method for determining the reliability of GPS data detected by GPS navigation, the DOP data is trusted by using the arrangement of received GPS satellites and the reliability data (DOP) in the GPS data. If it is determined that the directionality is low, the detected GPS data is not used to correct the direction and position detected by the self-contained navigation.
[0009]
However, DOP data generally represents the correctness of reliability, but the calculation method is greatly affected by the arrangement of visible satellites. Therefore, the reliability of GPS data is lower than actual in places where the sky view is not open. It may be judged. For this reason, in places such as urban areas where the sky is not very open, the DOP data may be “low reliability” even though the GPS data indicates the correct position and orientation. If such a state continues, there is a problem that the GPS data is not used effectively and the direction and position detected by the self-contained navigation are not corrected for a long time.
[0010]
An object of the present invention is to provide a navigation device that can appropriately determine the reliability of data detected by GPS navigation when correcting the current position and direction detected by self-contained navigation with GPS data.
[0011]
[Means for Solving the Problems]
  In order to achieve the above object, the present invention provides a self-contained navigation means for integrating a self-sustained movement vector detected by a turning angle sensor and a distance sensor to detect a vehicle position, and a vehicle position by receiving a radio wave from a GPS satellite. In a navigation apparatus provided with GPS navigation means for detecting the GPS, GPS vector calculation means for calculating a GPS movement vector indicating the traveling direction and speed of the vehicle based on data detected by the GPS navigation means, and the autonomous navigation means A self-supporting vector calculation means for calculating a self-supporting movement vector indicating the traveling direction and speed of the vehicle based on the data detected by the GPS, and a GPS movement vector at a plurality of measurement points calculated by the GPS vector calculation meansGPS difference calculation means for calculating GPS difference data indicating a difference between the two, and an independent difference calculation means for calculating independent difference data indicating differences between the independent movement vectors corresponding to the plurality of measurement points calculated by the independent vector calculation means Difference calculating means for calculating difference data indicating a difference between the GPS difference data calculated by the GPS difference calculating means and the independent difference data calculated by the independent difference calculating means, and a difference calculated by the difference calculating means Judgment means for judging that the reliability of the data detected by the GPS navigation means is high when the data is below a predetermined valueIt is characterized by comprising.
[0012]
  In addition, a self-contained navigation means for detecting the position of the own vehicle by integrating the independent movement vectors detected by the turning angle sensor and the distance sensor, and a GPS navigation means for detecting the position of the own vehicle by receiving radio waves from a GPS satellite are provided. In the navigation device, based on the data detected by the GPS navigation means, GPS vector calculation means for calculating a GPS movement vector indicating the traveling direction and speed of the vehicle, and based on the data detected by the independent navigation means A self-supporting vector calculation means for calculating a self-supporting movement vector indicating a traveling direction and a speed, and GPS movement vectors at a plurality of measurement points calculated by the GPS vector calculation meansAnd difference calculating means for calculating a plurality of difference data indicating differences between the independent movement vectors corresponding to the plurality of measurement points calculated by the independent vector calculating means, and a plurality of difference data calculated by the difference calculating means. Difference calculating means for calculating difference data indicating a difference; and determining means for determining the reliability of data detected by the GPS navigation means based on the difference data calculated by the difference calculating means; Determines the reliability of the data detected by the GPS navigation means when n pieces of the GPS movement vectors and the independent movement vectors are accumulated, and the accumulated number n of movement vectors is calculated from the GPS satellites. Fluctuates depending on the reception status ofIt is characterized by this.
  In addition, a self-contained navigation means for detecting the position of the own vehicle by integrating the independent movement vectors detected by the turning angle sensor and the distance sensor, and a GPS navigation means for detecting the position of the own vehicle by receiving radio waves from a GPS satellite are provided. In the navigation device, based on the data detected by the GPS navigation means, GPS vector calculation means for calculating a GPS movement vector indicating the traveling direction and speed of the vehicle, and based on the data detected by the independent navigation means A self-supporting vector calculating means for calculating a self-supporting movement vector indicating a traveling direction and a speed; a GPS moving vector at a plurality of measuring time points calculated by the GPS vector calculating means; and the plurality of measuring time points calculated by the self-standing vector calculating means. The difference which calculates the plural difference data which shows the difference of the independent movement vector which corresponds to Output means, difference calculating means for calculating difference data indicating a difference between the plurality of difference data calculated by the difference calculating means, and detected by the GPS navigation means based on the difference data calculated by the difference calculating means. And determining means for determining the reliability of the data, wherein the determining means determines the reliability of the data detected by the GPS navigation means when n each of the GPS movement vectors and the independent movement vectors are accumulated. The number n of the accumulated movement vectors determined is varied according to the frequency with which the GPS movement vector is abnormal.
  Further, the GPS difference calculation means calculates the bending angle of two continuous GPS movement vectors as difference data, and the self-supporting difference calculation means calculates the bending angle of two continuous independent movement vectors as difference data. It is characterized by.
[0013]
Further, the GPS vector calculation means calculates a GPS vector based on a plurality of position data detected by the GPS navigation means.
[0014]
Further, the GPS vector calculating means calculates a GPS vector based on a change in radio waves from a GPS satellite due to the Doppler effect detected by the GPS navigation means.
[0015]
In addition, when the GPS movement vector is abnormal, the determination means determines the reliability of the data detected by the GPS navigation means except for the abnormal GPS movement vector. is there.
[0016]
Further, the determination means determines the reliability of the data detected by the GPS navigation means when n pieces of the GPS movement vectors and the independent movement vectors are accumulated.
[0017]
In addition, the number n of movement vectors to be accumulated varies depending on the reception state of radio waves from the GPS satellite.
[0018]
In addition, the number n of movement vectors to be accumulated varies according to the frequency with which the GPS movement vector is abnormal.
[0019]
In addition, the apparatus includes an azimuth change detection unit that detects a change amount of the azimuth of the vehicle, and an integration unit that integrates an absolute value of the azimuth change amount detected by the azimuth change detection unit. The reliability of the data detected by the GPS navigation means is determined when the integrated amount of the absolute value of the accumulated azimuth variation exceeds a predetermined value.
[0020]
Further, when the determination means determines that the data detected by the GPS navigation means is highly reliable, the direction detected by the self-contained navigation means is corrected using the data detected by the GPS navigation means. It is characterized by comprising an azimuth correcting means.
[0021]
The vehicle position detected by the self-contained navigation means using the data detected by the GPS navigation means when the judgment means determines that the reliability of the data detected by the GPS navigation means is high. The vehicle position correcting means for correcting the vehicle is provided.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an explanatory diagram of a movement vector based on azimuth / speed data detected by GPS navigation. (A) is an explanatory diagram of a movement vector, (b) is an explanatory diagram of a vector difference 1, and (c) is an explanatory diagram of a vector difference 2. It is explanatory drawing. FIG. 2 is an explanatory diagram of reliability determination by multi-data accumulation processing. FIG. 3 is an explanatory diagram of reliability determination by abnormal data invalidation processing. FIG. 4 is an explanatory diagram of a movement vector based on GPS position data detected by GPS navigation. (A) is an explanatory diagram of the movement vector, (b) is an explanatory diagram of vector difference 1, and (c) is an explanation of vector difference 2. FIG. This will be described below with reference to the drawings. Note that the configuration of the apparatus is the same as that of a conventional navigation apparatus, and only the processing method of the control unit 2 is different.
[0023]
First, a method for determining reliability will be described with reference to FIG. The arrow C1 is a GPS movement vector C1 calculated based on the azimuth data and velocity data detected at regular intervals (for example, every second) by GPS navigation, and the arrow C2 is at regular intervals (for example, every second) by GPS navigation. ) GPS movement vector C2 calculated based on the detected azimuth data and velocity data.
[0024]
The arrow D1 indicates that the previous GPS was received by self-contained navigation (originally both navigations detected azimuth and speed at different periods with separate detection devices, but in order to compare both data, the detection timing of the GPS movement vector The self-contained movement vector D1 and the arrow D2 calculated based on the azimuth data and speed data detected at the time of synchronization or data combination processing at the time when there is no problem considering the detected data as simultaneous points are self-contained navigation Thus, the self-sustained movement vector D2 calculated based on the azimuth data and speed data detected at the time of the current GPS reception.
[0025]
In FIG. 1A, the GPS movement vectors C1 and C2 and the independent movement vectors D1 and D2 (the direction and size of the arrows) are greatly shifted. The main cause is the offset voltage shift due to the temperature change of the direction sensor. However, it cannot be corrected by judging that the detection result by GPS navigation is correct. The reason for this is that the positioning of GPS satellites that are also received by GPS navigation and the state of received radio waves, for example, when receiving GPS satellite radio waves directly at a position where GPS satellites can be seen, the detection position is highly reliable, but the radio waves of GPS satellites are This is because when it is received as a reflected wave by a building or the like, it is not reliable and may suddenly deviate from the true position.
[0026]
Next, the reliability judgment method will be described. The corresponding vector differences between the GPS movement vectors C1 and C2 and the independent movement vectors D1 and D2 are compared (see FIGS. 1B and 1C). That is, the vector difference Q1 between the GPS movement vector C1 and the independent movement vector D1 is obtained. Further, a vector difference Q2 between the GPS movement vector C2 and the independent movement vector D2 is obtained. Then, a difference Y1 between the vector difference Q1 and the vector difference Q2 is obtained. In self-contained navigation, the current position is calculated by integrating the movement vector consisting of the azimuth and speed detected at each time, but due to the characteristics of the gyro sensor, errors in the azimuth and distance are accumulated, and the current position calculated with time Gradually shifts from the true current position. However, a sudden change from the previous calculation position does not occur unlike GPS data. It can be said that the relative position measured by the self-contained navigation within this short time is correct. Therefore, when this difference Y1 is small, it can be said that there is no abnormality in the relative position measured by GPS navigation and the reliability of position, azimuth, and speed detection is high. According to another determination method, if the difference Y1 is small, the vector trajectories (D1 to D2) measured by the self-contained navigation are approximately coincident when rotated so as to overlap the vector trajectories (C1 to C2) measured by the GPS navigation. . In other words, the bending angle between the GPS movement vector C1 and the GPS movement vector C2 and the difference between the bending angle between the independent movement vector D1 and the independent movement vector D2 (and the difference between the absolute values, that is, corresponding to Y1) are determined. (Judgment can be made only by the difference in angle). This difference is completely related to the directions of the GPS movement vectors C1 and C2 and the independent movement vectors D1 and D2, and becomes small if the reliability of the GPS data is high.
[0027]
In the present embodiment, the vector difference Q1 between the GPS movement vector C1 and the independent movement vector D1 is calculated, and the vector difference Q2 between the GPS movement vector C2 and the independent movement vector D2 is calculated, and then the vector difference Q1 and the vector are calculated. Although the difference Q2 is calculated, as another method, the vector difference F1 between the GPS movement vector C1 and the GPS movement vector C2 is calculated, and the vector difference G1 between the independent movement vector D1 and the independent movement vector D2 is calculated. Later, the difference between the vector difference F1 and the vector difference G1 may be calculated.
[0028]
Although the above-described reliability determination method has been described using two movement vectors, the reliability of determination is improved by using a large number of data (movement vectors) as shown in FIG. In FIG. 2, C1, C2, C3, C4, and C5 are GPS movement vectors C1, C2, C3, C4, and C5, and D1, D2, D3, D4, and D5 are independent movement vectors D1, D2, D3, D4, D5. Further, vector differences Q1, Q2, Q3, Q4, and Q5 are obtained from both movement vectors, and the vector difference differences Y1 = (Q1 to Q2), Y2 = (Q2 to Q3), Y3 = (Q3 to Q4), Y4 = (Q4 to Q5) is obtained. When all vector difference differences (Y1, Y2, Y3, Y4) are below a predetermined value, it is determined that the GPS data is highly reliable. FIG. 2 illustrates five movement vectors. In this case, when one new data is acquired (after one second), one old data is deleted, and the number of data is always constant ( The data is updated sequentially one by one so that it becomes 5). Naturally, if the number of data n is increased, the reliability of the determination is improved, but if the number of data n is increased, the processing becomes troublesome and the data correction speed becomes slow. Therefore, the data is based on the reliability of the latest GPS data. The number n may be changed. For example, if the reliability of the latest GPS data is high, the number of data n is decreased, and if the reliability of the latest GPS data is low, the number of data n is increased (for example, 6 to 10). The reliability of GPS data is determined based on the number of GPS data that can be received continuously, DOP data, and the number of GPS satellites that can be received.
[0029]
Further, when a determination is made using a large number of data (movement vectors), it is necessary to make a determination after removing apparently abnormal data (movement vectors) from the comparison target. For example, in FIG. 3, when the CZ point of the GPS data is determined to be an abnormal point, a GPS movement vector C23 connecting both ends is used except for this point. At this time, the corresponding independent movement vector is similarly deleted and the independent movement vector D23 is adopted. Whether or not the data is invalid (abnormal point) is determined based on whether or not a radio wave is received from a GPS satellite, DOP data, and vehicle speed.
[0030]
Here, the case where the GPS movement vector C calculated based on the GPS azimuth data / GPS speed data detected by the GPS navigation is described, but the GPS movement calculated based on the GPS position data detected by the GPS navigation is described. It is also possible to determine the reliability of the GPS data using the vector A. In this case, as shown in FIG. 4, the GPS movement vector A1 is a GPS movement vector calculated from the position data at the time of the previous GPS reception and the position data at the previous GPS reception, and the GPS movement vector A2 is at the time of the previous GPS reception. And the GPS movement vector calculated from the position data at the time of the current GPS reception. The independent movement vector B1 is an independent movement vector from the previous GPS reception to the previous GPS reception, and the independent movement vector B2 is an independent movement vector from the previous GPS reception to the current GPS reception. In addition, the method for obtaining the vector differences P1 and P2, the method for obtaining the difference between the differences, the reliability determination by the multi-data integration process, and the reliability determination by the abnormal data invalidation process are substantially the same as those described with reference to FIGS. Is omitted.
[0031]
Next, a specific processing method for determining the reliability of the GPS detection data will be described using a flowchart. FIG. 5 is a flowchart of reliability determination processing performed by the control unit 2 of the navigation device according to the embodiment of the present invention. FIG. 6 is a diagram showing a movement vector when GPS data is abnormal. FIG. 7 is an explanatory diagram of the fluctuation of the self-supporting movement vector. Hereinafter, it demonstrates according to a figure. This process is repeatedly executed while the navigation device is in operation.
[0032]
In step S1, the reference number n is changed according to the GPS reception frequency, and the process proceeds to step S2. That is, the number n of data to be compared between detection data (movement vector data) by GPS navigation and detection data (movement vector data) by self-contained navigation is changed according to the reception state of past GPS radio waves. If the reception state of the GPS radio wave is good, it is determined that the reliability of the GPS data is high, and the number of data n to be compared is reduced, and if the reception state is bad, n is increased. If the number of data to be compared is reduced, there is an advantage that the direction and position correction of the self-contained navigation described later can be performed at an early stage. The reception state is determined from the number of data continuously received from GPS satellites, DOP data, the number of satellites that could be received, and the like. Although this flowchart is repeatedly executed, if the number n of data to be used cannot be determined without knowing the past reception state such as immediately after the power is turned on, a predetermined value (for example, n = 8) is temporarily set. Use it. In the following steps of processing in the navigation device of the present embodiment, the number of data to be compared n is changed depending on the reception state, but n = 8 (eight GPS movement vectors detected every second by GPS navigation, self-supporting A case where reliability is determined at the time when eight independent movement vectors detected every second by navigation are gathered will be described as an example.
[0033]
In step S2, data detected by GPS navigation (position data, bearing data, speed data, DOP data) and data detected by self-contained navigation (turning angle data, movement distance data) are read and synchronized (detected at the same point). Data that can be handled as data (for example, the data at the closest detection point is used as the detection data at the same point) is transferred to step S3. That is, data detected by the two navigations to be compared and stored in the memory (RAM) in the control unit 2 is read from the memory. GPS data is position data, azimuth data, speed data, DOP data, etc. detected by GPS navigation, turning angle data is data detected by an azimuth sensor (gyro sensor) 12, and movement distance data is data detected by a distance sensor 13. It is. Next, the data detected and detected by the two navigations are synchronized. For example, the first data detected by GPS navigation at 1 second intervals is associated with the first data detected by self-contained navigation, and the second data detected by GPS navigation corresponds to the second data detected by self-contained navigation Let In the same manner, the necessary number of data n (here, 8) are associated with each other. This synchronization is necessary when the data sampling periods (detection periods) or timings of the two navigations are different, and is unnecessary if both navigations are sampled at the same period (and the same timing).
[0034]
In step S3, it is determined whether or not the GPS data is valid. If the GPS data is valid, the process proceeds to step S4, and if not valid, the process ends. That is, it is determined that the case where the radio wave of the GPS satellite can be received is valid, and the case where the radio wave cannot be received in a tunnel or an underground parking lot is invalid. This determination is to determine the outline of the reception state of the GPS radio wave, and not to determine the reliability of each detected data. Further, since the detection accuracy is poor even when the amount of movement per unit time is small in GPS navigation, a method of determining invalidity when the vehicle speed detected by the distance sensor 13 in the self-contained navigation is low is also effective.
[0035]
In step S4, a GPS movement vector C is calculated from GPS azimuth data and speed data, and the process proceeds to step S5. That is, for the eight data detected by GPS navigation, the first GPS movement vector C1 is calculated from the first GPS azimuth data and velocity data as described in FIG. A second GPS movement vector C2 is calculated from the second GPS azimuth data and speed data. Similarly, the third GPS movement vector C3 to the eighth GPS movement vector C8 are calculated from the third to eighth GPS azimuth data and speed data.
[0036]
In step S5, an independent movement vector D is calculated from the turning angle data and speed data detected by the independent navigation, and the process proceeds to step S6. That is, for the eight data detected by the self-contained navigation, the first self-sustained movement vector D1 is calculated from the first turning angle data and speed data as described with reference to FIG. Also, a second self-sustained movement vector D2 is calculated from the second turning angle data and speed data. Similarly, the third independent movement vector D3 to the eighth independent movement vector D8 are calculated from the third to eighth turning angle data and speed data.
[0037]
In step S6, it is determined whether or not the fluctuation of the self-supporting movement vector (absolute value integration) is equal to or greater than a predetermined value. If the fluctuation is equal to or greater than the predetermined value, the process proceeds to step S7. Move on to S11. As shown in FIG. 6, in the case where the accuracy of GPS navigation decreases due to reception of unnecessary reflected waves of GPS radio waves as shown in FIG. 6, even if an abnormal vehicle position is output by GPS navigation in a straight section, the GPS calculated from GPS navigation is used. There are relatively many cases where the movement vector and the self-sustained movement vector are substantially straight lines (the vectors C1 and C2 are substantially in the same direction, and the vectors D1 and D2 are substantially in the same direction). In such a case, as described in the reliability determination diagram (FIG. 1), if both are straight sections, the vehicle position detected by GPS navigation may be determined to be correct even if it is abnormal. There is. Therefore, when the variation of each vector (the difference (absolute value) between the next vector such as the vector D1 and the vector D2) is small, the data in this section is not used for the determination. That is, the difference (absolute value) between the autonomous movement vector D1 and the autonomous movement vector D2, the difference (absolute value) between the autonomous movement vector D2 and the autonomous movement vector D3, and so on. Similarly, the difference between the autonomous movement vector D7 and the autonomous movement vector D8. (Absolute value) is calculated and integrated. Then, it is determined whether or not the integrated value is equal to or greater than a predetermined value. In FIG. 7, vector fluctuation angles θ1, θ2, θ3, and θ4 (all angles are absolute values) are used instead of vector fluctuations, and in this case, an integrated value Σθ = θ1 + θ2 + θ3 + θ4. Whether or not the integrated value Σθ is equal to or greater than a predetermined value is determined. If it is determined that the value is less than the predetermined value, the process ends. However, since this flowchart is repeatedly executed, one new data is added and one old data is deleted in the next process (in step S6). If it is equal to or greater than the predetermined value, the process proceeds to step S7. Further, when the process is completed when the integrated value Σθ is less than the predetermined value, the number of data n may be increased by one in step S1 of the next process.
[0038]
In step S7, it is determined whether or not there are n or more previous movement vector data. If there are n or more movement vector data, the process proceeds to step S8, and if it is less than n, the process proceeds to step S11. That is, in step S1, the number of vectors (n) to be compared by the two navigations is set. However, if the number of data is not n or more, the reliability in comparison is poor, so that the predetermined number of data (n = 8) is obtained. Judgment of the degree of agreement by both navigations is withheld.
[0039]
In step S8, the vector differences of the GPS movement vectors C1 to C8 and the independent movement vectors D1 to D8 are compared, and the process proceeds to step S9. That is, as described in FIG. 1, the vector difference Q1 between the GPS movement vector C1 and the independent movement vector D1 is obtained. Next, a vector difference Q2 between the GPS movement vector C2 and the independent movement vector D2 is obtained. Further, a vector difference Q3 between the GPS movement vector C3 and the independent movement vector D3 is obtained. In the same manner, eight vector differences are obtained up to the vector difference Q8 between the GPS movement vector C8 and the independent movement vector D8. Then, a difference Y1 between the vector difference Q1 and the vector difference Q2 is obtained. Thereafter, similarly, the difference data (Y1 to Y7) of the seven vector differences is calculated from the difference Y2 between the vector difference Q2 and the vector difference Q3 to the difference Y7 between the vector difference Q7 and the vector difference Q8.
[0040]
In step S9, it is determined whether or not the GPS data can be used. If the GPS data is usable, the process proceeds to step S10. If the GPS data is not usable, the process proceeds to step S11. That is, the determination is made based on whether or not all of the calculated seven vector difference difference data (Y1 to Y7) are equal to or less than a predetermined value. This determines whether or not each movement vector is changing in the same way (angle change and distance), and the GPS movement vectors C1 to C8 and the independent movement vectors D1 to D8 are rotated and overlapped. The degree of coincidence is judged.
[0041]
In step S10, position correction and azimuth correction are performed, and the process proceeds to step S11. That is, since it is determined that the reliability of the GPS data is high, the position and direction detected by the self-contained navigation are corrected so as to match the GPS data. The corrected position data, that is, position data used in the navigation device is stored at a predetermined address in the RAM in the control unit 2, and the stored position data is corrected based on the GPS data. Note that the correction method is the same as a general method, and a detailed description thereof will be omitted.
[0042]
In step S11, each vector data is preserve | saved and a process is complete | finished (it returns to step S1 since it processes repeatedly). That is, the calculated vector data is stored in order to compare the movement vector data in the next process.
[0043]
In this embodiment, the case where the GPS movement vector C is calculated from the GPS azimuth data and the GPS speed data in step S5 has been described. However, in this step S5, the GPS movement vector A is calculated from the GPS position data. (The details of the calculation method have already been described with reference to FIG. 4). In this case, nine pieces of position data (positions marked with x) are required to obtain the eight GPS movement vectors A1 to A8. The corresponding independent movement vectors are B1 to B8.
[0044]
As described above, in the present embodiment, the reliability of the GPS data is determined not by directly comparing the GPS movement vector and the independent movement vector, but by the change in the difference between the continuous movement vectors, and the shift of the direction sensor Therefore, the reliability of GPS data can be properly determined.
[0045]
【The invention's effect】
As described above, the present invention can provide a navigation device that can appropriately determine the reliability of data detected by GPS navigation when correcting the current position and direction detected by self-contained navigation with GPS data.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a movement vector based on azimuth / speed data detected by GPS navigation.
FIG. 2 is an explanatory diagram of reliability determination by multi-data accumulation processing.
FIG. 3 is an explanatory diagram of reliability determination by abnormal data invalidation processing;
FIG. 4 is an explanatory diagram of a movement vector based on position data detected by GPS navigation.
FIG. 5 is a flowchart of reliability determination processing performed by the control unit 2 of the navigation device according to one embodiment of the present invention.
FIG. 6 is a diagram showing a movement vector when GPS data is abnormal.
FIG. 7 is an explanatory diagram of fluctuations in a self-supporting movement vector.
FIG. 8 is a block diagram showing a configuration of a navigation device.
[Explanation of symbols]
11... GPS receiver, 2.
12 .... Direction sensor, 31 ... Input section,
13 ··· Distance sensor 41 ··· Display unit
14 .... Map database, 42 ... Voice output unit.

Claims

A navigation apparatus comprising self-contained navigation means for detecting the position of the own vehicle by integrating the independent movement vectors detected by the turning angle sensor and the distance sensor, and GPS navigation means for detecting the position of the own vehicle by receiving radio waves from a GPS satellite In
GPS vector calculation means for calculating a GPS movement vector indicating the traveling direction and speed of the vehicle based on the data detected by the GPS navigation means;
A self-sustained vector calculating means for calculating a self-supporting movement vector indicating the traveling direction and speed of the vehicle based on the data detected by the self-supporting navigation means;
GPS difference calculation means for calculating GPS difference data indicating differences in GPS movement vectors at a plurality of measurement points calculated by the GPS vector calculation means ;
Self-supporting difference calculation means for calculating self-supporting difference data indicating differences of self-supporting movement vectors corresponding to the plurality of measurement points calculated by the self-supporting vector calculation means;
A difference calculating means for calculating difference data indicating a difference between the GPS difference data calculated by the GPS difference calculating means and the independent difference data calculated by the independent difference calculating means;
A navigation apparatus, comprising: a determination unit that determines that the reliability of the data detected by the GPS navigation unit is high when the difference data calculated by the difference calculation unit is a predetermined value or less .

A navigation apparatus comprising self-contained navigation means for detecting the position of the own vehicle by integrating the independent movement vectors detected by the turning angle sensor and the distance sensor, and GPS navigation means for detecting the position of the own vehicle by receiving radio waves from a GPS satellite In
GPS vector calculation means for calculating a GPS movement vector indicating the traveling direction and speed of the vehicle based on the data detected by the GPS navigation means;
A self-sustained vector calculating means for calculating a self-supporting movement vector indicating the traveling direction and speed of the vehicle based on the data detected by the self-supporting navigation means;
A difference for calculating a plurality of difference data indicating a difference between a GPS movement vector at a plurality of measurement points calculated by the GPS vector calculation unit and an independent movement vector corresponding to the plurality of measurement points calculated by the independent vector calculation unit. A calculation means;
Difference calculating means for calculating difference data indicating a difference between a plurality of difference data calculated by the difference calculating means;
Determining means for determining the reliability of the data detected by the GPS navigation means based on the difference data calculated by the difference calculating means;
The determination means determines the reliability of the data detected by the GPS navigation means at the time when n pieces of the GPS movement vectors and the independent movement vectors are accumulated, respectively.
The navigation apparatus according to claim 1, wherein the number n of the accumulated movement vectors varies depending on a reception state of radio waves from the GPS satellite .

A navigation apparatus comprising self-contained navigation means for detecting the position of the own vehicle by integrating the independent movement vectors detected by the turning angle sensor and the distance sensor, and GPS navigation means for detecting the position of the own vehicle by receiving radio waves from a GPS satellite In
GPS vector calculation means for calculating a GPS movement vector indicating the traveling direction and speed of the vehicle based on the data detected by the GPS navigation means;
A self-sustained vector calculating means for calculating a self-supporting movement vector indicating the traveling direction and speed of the vehicle based on the data detected by the self-supporting navigation means;
A difference for calculating a plurality of difference data indicating a difference between a GPS movement vector at a plurality of measurement points calculated by the GPS vector calculation unit and an independent movement vector corresponding to the plurality of measurement points calculated by the independent vector calculation unit. A calculation means;
Difference calculating means for calculating difference data indicating a difference between a plurality of difference data calculated by the difference calculating means;
Determining means for determining the reliability of the data detected by the GPS navigation means based on the difference data calculated by the difference calculating means;
The determination means determines the reliability of the data detected by the GPS navigation means at the time when n pieces of the GPS movement vectors and the independent movement vectors are accumulated, respectively.
The number n of the accumulated movement vectors varies depending on the frequency with which the GPS movement vector is abnormal .

The GPS difference calculating means calculates a bending angle between two continuous GPS movement vectors as difference data,
The navigation device according to claim 1, wherein the self-supporting difference calculating unit calculates a bending angle between two continuous self-supporting movement vectors as difference data.

The navigation apparatus according to any one of claims 1 to 4, wherein the GPS vector calculation means calculates a GPS vector based on a plurality of position data detected by the GPS navigation means.

The GPS vector calculating means, the navigation device according to any one of claims 1 to 4, characterized in that to calculate the GPS vector based on the radio waves changes from GPS satellites by Doppler effect GPS navigation means detects .

The determination means includes
The GPS mobile When vector is abnormal, the any one of claims 1, characterized in that to determine the reliability of the detected data by GPS motion vector the GPS navigation means except with the abnormal 6 The navigation device according to item .

The determination means includes
The navigation device according to claim 1, characterized in that to determine the reliability of data to which the autonomous moving vector and the GPS mobile vector is detected by the GPS navigation unit at the time of the n pieces integrated respectively.

The number n of accumulated movement vectors is
9. The navigation apparatus according to claim 8 , wherein the navigation apparatus varies depending on a reception state of radio waves from the GPS satellite.

The number n of accumulated movement vectors is
9. The navigation device according to claim 8, wherein the GPS movement vector is changed according to an abnormal frequency.

Azimuth change detecting means for detecting the amount of change in the azimuth of the vehicle;
An integrating means for integrating the absolute value of the amount of change in orientation detected by the orientation change detecting means;
The determination means includes
Wherein when the accumulated amount of the absolute value of the change amount of the accumulated azimuth exceeds a predetermined value by the integrating means, we claim 1, characterized in that to determine the reliability of the data detected by the GPS navigation device 3 The navigation device according to any one of the above.

An azimuth that corrects the azimuth detected in the self-contained navigation means using the data detected by the GPS navigation means when the judgment means determines that the reliability of the data detected by the GPS navigation means is high. the navigation device according to any one of claims 1 to 11, further comprising a correction means.

When the determination means determines that the reliability of the data detected by the GPS navigation means is high, the vehicle position detected by the self-contained navigation means is corrected using the data detected by the GPS navigation means. The navigation device according to any one of claims 1 to 11, further comprising: a vehicle position correcting means for performing the operation.