JP2004085222A

JP2004085222A - Positioning apparatus of mobile unit, positioning method, and computer program

Info

Publication number: JP2004085222A
Application number: JP2002242922A
Authority: JP
Inventors: Hajime Takemura; 武村　肇
Original assignee: Pioneer Electronic Corp
Current assignee: Pioneer Corp
Priority date: 2002-08-23
Filing date: 2002-08-23
Publication date: 2004-03-18

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high reliability positioning apparatus or the like of a mobile unit. <P>SOLUTION: The positioning apparatus comprises a measurement pseudo distance calculation means for calculating a measurement pseudo distance based on a GPS signal received from a plurality of GPS satellites; a prediction position calculating means for calculating the predicted position of the mobile unit, based on the travelling speed and traveling azimuth of the mobile unit; a prediction pseudo-distance calculating means for calculating the predicted position of the mobile unit and the predicted pseudo distance to respective GPS satellites, based on the orbit information of the GPS satellites; and a positioning advisability determinating means for determining whether the current position of the mobile unit should be calculated based on the comparison result between the measurement pseudo-distance and a predicted pseudo-distance. Additionally, instead of the positioning advisability determinating means, a most probable pseudo-distance deciding means for determining the most probable pseudo-distance, based on the comparison result of the measurement pseudo-distance and the prediction pseudo-distance; and a current position calculation means for calculating the current position of the mobile unit, based on the orbit information of the GPS satellite and each most probable pseudo-distance are provided. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、移動体の現在位置を測位する測位装置、測位方法及び測位装置を機能させるコンピュータプログラムに関する。
【０００２】
【従来の技術】
例えば、自動車、航空機、船舶等の各種の移動体の位置を測位する測位装置として、ＧＰＳ（Ｇｌｏｂａｌ　Ｐｏｓｉｔｉｏｎｉｎｇ　Ｓｙｓｔｅｍ　）を利用した測位装置が一般的に知られている。
【０００３】
従来のＧＰＳを利用した測位は次のようにしておこなわれる。まず、ＧＰＳ受信機で、宇宙空間に打ち上げられている複数のＧＰＳ衛星から発信されるＧＰＳ信号を受信すると伴に、該ＧＰＳ信号を受信した時の受信時刻を記録する。そして、受け取ったＧＰＳ信号から時刻情報を取り出して、ＧＰＳ信号の発信時刻を特定し、前記受信時刻との差をとってＧＰＳ信号の伝搬時間を算出する。このＧＰＳ伝搬時間に伝搬速度（光速）をかけることで、ＧＰＳ衛星から受信機までの測定上の距離である測定擬似距離が求められる。また、ＧＰＳ信号にはＧＰＳ衛星の軌道情報が含まれているので、該軌道情報からＧＰＳ衛星の衛星位置を特定することができる。この衛星位置と前述の測定擬似距離とで、測位位置を含んだ球面が定まる。この球面を、複数の衛星から受信したＧＰＳ信号に基づいて３乃至４個以上定めれば、これらの球面の交点として測位位置を求めることができる。
【０００４】
【発明が解決しようとする課題】
しかしながら、この従来の測位装置を用いて、市街地などにおいて測位をおこなう場合、ＧＰＳ衛星から発信されたＧＰＳ信号がビルなどの高層の建物に反射することがある。ＧＰＳ受信機でこの反射したＧＰＳ信号を受信して測定擬似距離を算出した場合、この測定擬似距離には多大な誤差が含まれ、これに基づいて算出した測位位置の信頼性が低下するという問題がある。
【０００５】
本発明が解決しようとする課題は、上述した問題が一例として挙げられる。
【０００６】
【課題を解決するための手段】
請求項１に記載の発明は、複数のＧＰＳ衛星から受信したＧＰＳ信号に基づいて、移動体と前記各ＧＰＳ衛星との測定擬似距離を算出する測定擬似距離算出手段と、前記移動体の移動速度及び移動方位を認識し、該移動速度及び該移動方位に基づいて前記移動体の予測位置を算出する予測位置算出手段と、前記各ＧＰＳ信号に含まれる前記ＧＰＳ衛星の軌道情報に基づいて、前記移動体の予測位置と前記各ＧＰＳ衛星との予測擬似距離を算出する予測擬似距離算出手段と、前記各ＧＰＳ衛星に対して、前記測定擬似距離と前記予測擬似距離とを比較し、その結果に基づいて前記移動体の現在位置の算出をおこなうか否かを決定する測位可否決定手段と、を備えたことを特徴とする移動体の測位装置を提供する。
【０００７】
請求項４に記載の発明は、複数のＧＰＳ衛星から受信したＧＰＳ信号に基づいて、移動体と前記各ＧＰＳ衛星との測定擬似距離を算出する測定擬似距離算出手段と、前記移動体の移動速度及び移動方位を認識し、該移動速度及び該移動方位に基づいて前記移動体の予測位置を算出する予測位置算出手段と、前記各ＧＰＳ信号に含まれる前記ＧＰＳ衛星の軌道情報に基づいて、前記移動体の予測位置と前記各ＧＰＳ衛星との予測擬似距離を算出する予測擬似距離算出手段と、前記各ＧＰＳ衛星に対して、前記測定擬似距離と前記予測擬似距離とを比較し、その結果に基づいて最確擬似距離を決定する最確擬似距離確定手段と、前記ＧＰＳ衛星の軌道情報と前記各最確擬似距離とに基づいて前記移動体の現在位置を算出する現在位置算出手段と、を備えたことを特徴とする移動体の測位装置を提供する。
【０００８】
請求項１２に記載の発明は、複数のＧＰＳ衛星から受信したＧＰＳ信号に基づいて、移動体と前記各ＧＰＳ衛星との測定擬似距離を算出する測定擬似距離算出工程と、前記移動体の移動速度及び移動方位を認識し、該移動速度及び該移動方位に基づいて前記移動体の予測位置を算出する予測位置算出工程と、前記各ＧＰＳ信号に含まれる前記ＧＰＳ衛星の軌道情報に基づいて、前記移動体の予測位置と前記各ＧＰＳ衛星との予測擬似距離を算出する予測擬似距離算出工程と、前記各ＧＰＳ衛星に対して、前記測定擬似距離と前記予測擬似距離とを比較し、その結果に基づいて前記移動体の現在位置の算出をおこなうか否かを決定する測位可否決定工程と、を含むことを特徴とする移動体の測位方法を提供する。
【０００９】
請求項１３に記載の発明は、複数のＧＰＳ衛星から受信したＧＰＳ信号に基づいて、移動体と前記各ＧＰＳ衛星との測定擬似距離を算出する測定擬似距離算出工程と、前記移動体の移動速度及び移動方位を認識し、該移動速度及び該移動方位に基づいて前記移動体の予測位置を算出する予測位置算出工程と、前記各ＧＰＳ信号に含まれる前記ＧＰＳ衛星の軌道情報に基づいて、前記移動体の予測位置と前記各ＧＰＳ衛星との予測擬似距離を算出する予測擬似距離算出工程と、前記各ＧＰＳ衛星に対して、前記測定擬似距離と前記予測擬似距離とを比較し、その結果に基づいて最確擬似距離を決定する最確擬似距離確定工程と、前記ＧＰＳ衛星の軌道情報と前記各最確擬似距離とに基づいて前記移動体の現在位置を算出する現在位置算出工程と、を含むことを特徴とする移動体の測位方法を提供する。
【００１０】
請求項１４に記載の発明は、移動体の測位装置に含まれるコンピュータを、複数のＧＰＳ衛星から受信したＧＰＳ信号に基づいて、移動体と前記各ＧＰＳ衛星との測定擬似距離を算出する測定擬似距離算出手段と、前記移動体の移動速度及び移動方位を認識し、該移動速度及び該移動方位に基づいて前記移動体の予測位置を算出する予測位置算出手段と、前記各ＧＰＳ信号に含まれる前記ＧＰＳ衛星の軌道情報に基づいて、前記移動体の予測位置と前記各ＧＰＳ衛星との予測擬似距離を算出する予測擬似距離算出手段と、前記各ＧＰＳ衛星に対して、前記測定擬似距離と前記予測擬似距離とを比較し、その結果に基づいて前記移動体の現在位置の算出をおこなうか否かを決定する測位可否決定手段と、して機能させることを特徴とするコンピュータプログラムを提供する。
【００１１】
請求項１５に記載の発明は、移動体の測位装置に含まれるコンピュータを、複数のＧＰＳ衛星から受信したＧＰＳ信号に基づいて、移動体と前記各ＧＰＳ衛星との測定擬似距離を算出する測定擬似距離算出手段と、前記移動体の移動速度及び移動方位を認識し、該移動速度及び該移動方位に基づいて前記移動体の予測位置を算出する予測位置算出手段と、前記各ＧＰＳ信号に含まれる前記ＧＰＳ衛星の軌道情報に基づいて、前記移動体の予測位置と前記各ＧＰＳ衛星との予測擬似距離を算出する予測擬似距離算出手段と、前記各ＧＰＳ衛星に対して、前記測定擬似距離と前記予測擬似距離とを比較し、その結果に基づいて最確擬似距離を決定する最確擬似距離確定手段と、前記ＧＰＳ衛星の軌道情報と前記各最確擬似距離とに基づいて前記移動体の現在位置を算出する現在位置算出手段と、して機能させることを特徴とするコンピュータプログラムを提供する。
【００１２】
【発明の実施の形態】
本発明に好適な実施の形態について、図面に基づいて説明する。なお、以下に説明する各実施の形態は、車載用ナビゲーション装置に本発明を適用した場合の実施の形態である。
【００１３】
［第１実施形態］
まず、図１を参照して、本発明の第１実施形態に係る車載用ナビゲーション装置の構成および機能について説明する。
【００１４】
図１は、車載用ナビゲーション装置の概要ブロック図である。図１に示すように、車載用ナビゲーション装置１はＧＰＳ衛星より発信されるＧＰＳ信号を受信して測位に必要な情報を取得し、測位位置を算出するＧＰＳ受信機２と、各部の制御をおこなう制御部３と、ユーザの指示を受け付ける操作部４と、ＣＤ−ＲＯＭなどに蓄積された地図情報を読み出し、取得する地図情報取得部５と、測位結果などを表示する表示部６とを備えている。
【００１５】
ＧＰＳ受信機２は、ＧＰＳ信号を受信する受信アンテナ、受信したＧＰＳ信号を周波数変換し更に増幅する周波数変換／増幅部、ＧＰＳ信号を復調する復調部、演算をおこなうＣＰＵ、データなどの一次保存に用いるＲＡＭ、コンピュータプログラムなどを保存したＲＯＭなど、公知のＧＰＳ受信装置と同様の構成部分を備えており、ＲＯＭに保存されたコンピュータプログラムでＣＰＵを測定擬似距離算出手段、予測位置算出手段、予測擬似距離算出手段、最確擬似距離確定手段及び現在位置算出手段として機能させる。
【００１６】
制御部３は、ＣＰＵ、ＲＡＭおよびＲＯＭなどを備えており、ＧＰＳ受信機２、操作部４、地図情報取得部５および表示部６などの制御をおこなう。具体的には、操作部４からの指示に従って、ＧＰＳ受信機２を動作させて現在位置を測位させ、該測位結果を地図情報取得部５から取得した地図情報と伴に表示部６に表示する。
【００１７】
操作部４は、例えば、タッチパネルなどにより構成され、ユーザは操作部４により、各種の指示や環境設定などをおこなう。
【００１８】
地図情報取得部５は、例えば、公知のＣＤ−ＲＯＭ再生装置であり、ＣＤ−ＲＯＭなどに蓄積された地図情報などを読み出し、制御部３に出力する。
【００１９】
表示部６は、例えば、液晶表示装置などで構成され、ＧＰＳ受信機２の測位結果を表示する。測位結果の表示は、上述のように、地図情報取得部５から出力された地図情報データに基づいて表示した地図上の該当位置に、自車マークを表示するなどしておこなう。
【００２０】
先ず、図２を参照して、車載用ナビゲーション装置１における測位の特徴的部分について説明する。
【００２１】
図２に示すように、衛星位置Ｓ２にあるＧＰＳ衛星ＳからＧＰＳ信号を受信し、このＧＰＳ信号に基づいて測定擬似距離を算出する。図２の場合、ＧＰＳ信号は、ＧＰＳ受信機で受信するまでの間にビルＢで反射されているので、このＧＰＳ信号に基づいて算出された測定擬似距離は、正規の距離より長い距離として算出される。
【００２２】
一方、前回測位時の自車位置Ｐからの自車の移動速度及び移動方位を検出して、今回測位時の自車の予測位置Ｎを算出する。また、ＧＰＳ信号に含まれる軌道情報（エフェメリス）により今回測位時の衛星位置Ｓ２を算出する。そして、予測位置Ｎと衛星位置Ｓ２との距離を予測擬似距離として算出する。
【００２３】
次に、測定擬似距離と予測擬似距離とを比較し、その比較結果に基づいて、１）自車の現在位置の算出をおこなうか否かを決定する、又は、２）最確擬似距離を決定して、この最確擬似距離とＧＰＳ信号に含まれる軌道情報とに基づいて自車の現在位置の算出をおこなう。すなわち、測定擬似距離と予測擬似距離との差が大きいときは、測定擬似距離に大きな誤差が含まれている可能性があるので、１）現時位置の算出を中止したり、２）測定擬似距離を補正した最確擬似距離に基づいて現在位置の算出をおこなったりする。
【００２４】
次に、図３を参照して、車載用ナビゲーション装置１における測位処理手順について詳細に説明する。
【００２５】
車載用ナビゲーション装置１は、操作部４で「測位開始」の指示が入力されることにより、測位を開始する。
【００２６】
ステップ１は、ＧＰＳ受信機２がＧＰＳ衛星からＧＰＳ信号を受信するステップである。ＧＰＳ受信機２は、宇宙空間に打ち上げられている複数のＧＰＳ衛星の中から、捕捉可能なＧＰＳ衛星を３乃至４個以上選び出し、これらのＧＰＳ衛星から発信されるＧＰＳ信号を同時に受信する。また、ＧＰＳ受信機２は、該ＧＰＳ信号を受信したときの時刻（受信時刻）を記録する。なお、ＧＰＳ信号には、ＧＰＳ信号の発信時刻などの時刻情報や、ＧＰＳ衛星の軌道に関する情報（軌道情報）などが含まれる。
【００２７】
ステップ２は、ＧＰＳ受信機２が測定擬似距離を算出するステップである。ＧＰＳ受信機２は、ステップ１で受信したＧＰＳ信号から時刻情報を取り出し、該ＧＰＳ信号の発信時刻を特定する。そして、この発信時刻とステップ１で記録した受信時刻から、該ＧＰＳ信号がＧＰＳ衛星で発信されてからＧＰＳ受信機２で受信されるまでの時間（伝搬時間）を算出する。更に、この伝搬時間にＧＰＳ信号の伝搬速度（光速）をかけて、ＧＰＳ衛星とＧＰＳ受信機２との測定上の距離である測定擬似距離を算出する。なお、この測定擬似距離には、ＧＰＳ信号のビルなどへの反射に伴う誤差など、様々な誤差を含んでいる可能性がある。
【００２８】
ステップ３は、自車の移動速度及び移動方位から、今回測位時の自車予測位置を算出するステップである。前回の測位で受信したＧＰＳ信号から、自車の移動速度および移動方位を特定する。また、前回の測位から今回の測位までの経過時間を算出する。このようにして得られた移動速度、移動方位及び経過時間に基づいて、前回測位時の自車位置に対する今回測位時の自車相対位置を算出する。そして、前回測位時の自車位置にこの自車相対位置を加えて、今回測位時の自車予測位置を算出する。
【００２９】
ステップ４は、予測擬似距離を算出するステップである。ステップ１で受信したＧＰＳ信号から軌道情報を読み出し、該軌道情報から今回測位時におけるＧＰＳ衛星の衛星位置を特定する。そして、この衛星位置とステップ３で算出した今回測位時の自車予測位置との２点間の距離を、予測擬似距離として算出する。
【００３０】
ステップ５は、誤差判断の基準値（誤差基準値）を決定するステップである。誤差基準値は、ステップ６において測定擬似距離と予測擬似距離との比較をする際に、ものさしとして用いられる基準値である。すなわち、測定擬似距離と予測擬似距離との距離差と誤差基準値を比較して、距離差が誤差基準値を超えるときは測定擬似距離に含まれる誤差は大きく、超えないときは誤差は小さいと判断するための基準値である。
【００３１】
この誤差基準値は、前回の測位から今回の測位までの経過時間に基づいて決定する。すなわち、経過時間が長いときは自車の移動速度及び移動方位に基づいて算出した自車予測位置の信頼性、ひいては予測擬似距離の信頼性が低くなり、相対的に測定擬似距離を重視して判断するため、誤差基準値を大きく設定する。一方、経過時間が短い時は、予測擬似距離の信頼性が高くなり、相対的に予測擬似距離を重視して判断するため、誤差基準値を小さく設定する。なお、ここでいう経過時間とは、測位結果まで算出することができた前回の測位からの経過時間をいう。すなわち、衛星の捕捉ができなかったり、誤差により測位結果が得られなかったりする場合があるが、これらの測位は考慮しない。
【００３２】
ステップ６は、測定擬似距離と予測擬似距離とを比較して、測定擬似距離に含まれる誤差を判断するステップである。上述のように、測定擬似距離と予測擬似距離との距離差と誤差基準値を比較することで、測定擬似距離と予測擬似距離との比較をおこない、距離差が誤差基準値を超えるときは測定擬似距離に含まれる誤差は大きく、超えないときは誤差は小さいと判断する。
【００３３】
ステップ７は、最確擬似距離を決定するステップである。最確擬似距離は、ステップ６での判断結果に基づいて決定する。例えば、ステップ６で測定擬似距離の誤差が小さいと判断した場合は、測定擬似距離を最確擬似距離として設定し（ステップ７Ａ）、誤差が大きいと判断した場合は、予測擬似距離を最確擬似距離として設定する（ステップ７Ｂ）。なお、測定擬似距離の誤差が大きいと判断した場合は、確定擬似距離は測定不能であるとして決定し、該測定不能と決定したＧＰＳ衛星以外のＧＰＳ衛星についての確定擬似距離に基づいて、以下ステップ８で現在位置の算出をおこなってもよい。
【００３４】
ステップ８は、自車の現在位置を算出するステップである。ステップ１で捕捉した各ＧＰＳ衛星について、上記各ステップの結果、最確擬似距離と衛星位置が求められる。そして、この衛星位置を中心として最確擬似距離を半径とする球面を各ＧＰＳ衛星に対して設定する。このようにして得られた各球面は、自車の現在位置を含んでおり、これらの球面の交点を算出すれば自車の現在位置を算出することができる。
【００３５】
このとき、例えば、ＧＰＳ衛星からＧＰＳ信号を受信し、現在位置を算出するのにＧＰＳ衛星の選択が可能な場合に、ステップ６において測定擬似距離に含まれる誤差が大きいと判断されたＧＰＳ衛星についての最確擬似距離は使用せず、測定擬似距離に含まれる誤差が小さいと判断されたＧＰＳ衛星についての最確擬似距離のみに基づいて現在位置を算出してもよい。
【００３６】
そして、操作部４から「測位終了」の指示が為されるまでは、ステップ１からステップ８が繰り返され、「測位終了」の指示が為された場合に測位を終了する（ステップ９）。
【００３７】
なお、以上においては、測定擬似距離と予測擬似距離との比較結果に基づいて最確擬似距離を決定したが、測定擬似距離と予測擬似距離との比較結果に基づいて現時位置の算出をおこなうか否かを決定してもよい。この場合、上記ステップ７及び８は、次のステップ１０に置き換えられる。
【００３８】
すなわち、ステップ１０は、ステップ６の判断結果に基づいて、自車の現在位置の算出をおこなうか否かを判断するステップである。すなわち、ステップ６で測定擬似距離の誤差が小さいと判断した場合は、測定擬似距離及び軌道情報に基づいて自車の現在位置の算出をおこない、一方、測定擬似距離の誤差が大きいと判断した場合は、自車の現在位置の算出はおこなわず、続いておこなわれるステップ９で「測位終了」の指示がなされない場合は引き続きステップ１に戻って処を続ける。また、ステップ１０で測定擬似距離の誤差が小さいと判断し、自車の現在位置の算出をおこなうことを決定した場合に、引き続いてステップ７及び８の処理をおこなってもよい。この場合、誤差基準値を大小２段階で定めて、自車の現在位置の算出をおこなうか否かを判断する際の誤差基準値には大きいほうの基準値を用い、最確擬似距離を決定する際の誤差基準値には小さいほうの基準値を用いればよい。すなわち、測定擬似距離と予測擬似距離の距離差が極めて大きいときは現在位置の算出を中止し、距離差が比較的多きときは最確擬似距離として予測擬似距離を定め、距離差が小さいときは最確擬似距離として測定議事距離を定めるようにすればよい。これにより、一層信頼性のある現在位置の算出をおこなうことができる。
【００３９】
以上説明したように、第１実施形態に係る車載用ナビゲーション装置１は、複数のＧＰＳ衛星から受信したＧＰＳ信号に基づいて自車と各ＧＰＳ衛星との測定擬似距離を算出し、また自車の移動速度及び移動方位に基づいて算出した自車予測位置と各ＧＰＳ信号に含まれる軌道情報（エフェメリス）で得られた衛星位置とに基づいて予測擬似距離を算出し、そして測定擬似距離と予測擬似距離とを比較し、その結果に基づいて、１）自車の現在位置の算出をおこなうか否かを判断する、又は、２）最確擬似距離を確定し、この最確擬似距離と軌道情報から得られた衛星位置とに基づき自車の現在位置を算出する。これによれば、測位擬似距離を大きな誤差が含まれることが比較的少ない予測擬似距離と比較することで、測位擬似距離に大きな誤差が含まれないかを判断でき、その判断結果に基づいて自車の現時位置を算出するので、測位の信頼性を向上できる。
【００４０】
また、自車の移動速度及び移動距離をＧＰＳ信号に基づいて特定する。これによれば、他の測定機器などを特に用いることなく自車の移動速度及び移動距離を特定することができる。
【００４１】
また、前述の測定擬似距離と予測擬似距離との比較は、測定擬似距離と予測擬似距離との距離差が誤差基準値を越えるか否かによって判断する。これによれば、画一的に両者を比較することができ、また誤差基準値を操作することによって容易に判断レベルを変更（調節）することができる。
【００４２】
また、前述の誤差基準値を、前回の測位から今回の測位までの経過時間に基づいて定める。これによれば、経過時間が短いときは予測擬似距離の信頼性が高いため誤差基準値を小さくして、予測擬似距離を重視した測位擬似距離の誤差判断ができ、一方、経過間隔が長いときは予測擬似距離の信頼性が低いため誤差基準値を大きくして、測定擬似距離を重視した測位擬似距離の誤差判断ができる。
【００４３】
［第２実施形態］
第２実施形態は、自車の速度・方位の算出に車速センサおよびジャイロセンサを用いる車載用ナビゲーション装置における実施形態である。
【００４４】
先ず、図４を参照して、本発明の第２実施形態に係る車載用ナビゲーション装置の構成および機能について説明する。
【００４５】
図４は、車載用ナビゲーション装置の概要ブロック図である。図４に示すように、車載用ナビゲーション装置１１は、第１実施形態にかかる車載用ナビゲーション装置に車速センサ１７およびジャイロセンサ１８を付加して構成される。
【００４６】
車速センサ１７は、移動速度検出手段を構成し、車輪の回転に伴って発生する車速パルスから、自車の移動速度を検出する。また、ジャイロセンサ１８は、移動方位検出手段を構成し、自車の方向変換時の角速度から、自車の移動方位を検出する。車速センサ１７及びジャイロセンサ１８は、ＧＰＳ受信機２に接続され、それぞれ検出した移動速度及び移動方位をＧＰＳ受信機２に送信する。ＧＰＳ受信機２は、送信された移動速度及び移動方位に基づいて、自車の予測位置を算出する。
【００４７】
車載用ナビゲーション装置１１の他の構成要素は、第１実施形態と同一の機能を有するので同一符号を付し、説明を省略する。
【００４８】
次に、車載用ナビゲーション装置１１における測位処理手順について説明するが、第２実施形態における測位処理手順は、第１実施形態における測位処理手順とステップ３においてのみ異なるので、以下ステップ３について説明する。
【００４９】
ステップ３は、第１実施形態と同様に、移動体である自車の移動速度及び移動方位から、今回測位時の自車予測位置を算出するステップである。第２実施形態では、車速センサ１７で検出した自車の移動速度とジャイロセンサ１８で検出した自車の移動方位とに基づいて今回測位時の自車予測位置を算出する。すなわち、車速センサ１７は、自車の車輪の回転に伴って発生する車速パルスを検出して、これに基づいて自車の移動速度を特定して、ＧＰＳ受信機２に送信する。また、ジャイロセンサ１８は、自車の方向変換時の角速度を検出し、これに基づいて自車の移動方位を特定して、ＧＰＳ受信機２に送信する。ＧＰＳ受信機２では、送信された自車の移動速度及び移動方位から、今回測位時の自車予測位置を算出する。
【００５０】
他のステップについては、第１実施形態と同一であるので説明を省略する。
【００５１】
以上説明したように、第２実施形態に係る車載用ナビゲーション装置１１は、第１実施形態に係る車載用ナビゲーション装置１と異なり、移動速度検出手段としての車速センサ１７で自車の移動速度を検出し、また、移動方位検出手段としてのジャイロセンサ１８で自車の移動方位を検出する。これによれば、自車の移動速度及び移動方位をより正確に特定することが可能となり、測位の信頼性が一層向上する。
【００５２】
［他の実施形態］
上記各実施形態に係る車載用ナビゲーション装置は、ＧＰＳ受信機に含まれるＣＰＵを、ＲＯＭに保存されたコンピュータプログラムで測定擬似距離算出手段、予測位置算出手段、予測擬似距離算出手段、最確擬似距離確定手段及び現在位置算出手段又は測位可否判断手段として機能させたが、制御部に含まれるＣＰＵを、ＲＯＭに保存されたコンピュータプログラムで上記各手段として機能させてもよい。
【００５３】
また、上記各実施形態では、車載用ナビゲーション装置に関して説明したが、本発明はこれに限られず、例えば携帯用ナビゲーション装置にも適用できる。携帯用ナビゲーション装置の場合、移動速度検出手段として、第２実施形態における車速センサに変えて、例えば歩数によって距離を測定する万歩計（登録商標）を応用した速度センサを用いればよい。
【図面の簡単な説明】
【図１】第１実施形態に係る車載用ナビゲーション装置の概要ブロック図である。
【図２】載用ナビゲーション装置における測位処理を説明する図である。
【図３】第１実施形態に係る車載用ナビゲーション装置における測位処理手順のフローチャートである。
【図４】第２実施形態に係る車載用ナビゲーション装置の概要ブロック図である。
【符号の説明】
１　車載用ナビゲーション装置
２　ＧＰＳ受信機
３　制御部
４　操作部
５　地図情報取得部
６　表示部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a positioning device that measures a current position of a moving object, a positioning method, and a computer program that causes the positioning device to function.
[0002]
[Prior art]
For example, a positioning device using a GPS (Global Positioning System) is generally known as a positioning device for positioning the position of various moving objects such as an automobile, an aircraft, and a ship.
[0003]
The positioning using the conventional GPS is performed as follows. First, a GPS receiver receives GPS signals transmitted from a plurality of GPS satellites launched into outer space, and records the reception time when the GPS signals were received. Then, time information is extracted from the received GPS signal, the transmission time of the GPS signal is specified, and the propagation time of the GPS signal is calculated by taking the difference from the reception time. By multiplying the GPS propagation time by the propagation speed (light speed), a measured pseudo distance, which is a measured distance from the GPS satellite to the receiver, is obtained. In addition, since the GPS signal includes the orbit information of the GPS satellite, the satellite position of the GPS satellite can be specified from the orbit information. The spherical surface including the positioning position is determined by the satellite position and the above-described measured pseudo distance. If three or four or more spherical surfaces are determined based on GPS signals received from a plurality of satellites, a positioning position can be obtained as an intersection of these spherical surfaces.
[0004]
[Problems to be solved by the invention]
However, when positioning is performed in an urban area or the like using this conventional positioning device, a GPS signal transmitted from a GPS satellite may be reflected on a high-rise building such as a building. When the GPS receiver receives the reflected GPS signal and calculates the measurement pseudo distance, the measurement pseudo distance includes a large error, and the reliability of the positioning position calculated based on the error decreases. There is.
[0005]
Problems to be solved by the present invention include the above-mentioned problem as an example.
[0006]
[Means for Solving the Problems]
The invention according to claim 1 is a measurement pseudo distance calculating means for calculating a measurement pseudo distance between a moving object and each of the GPS satellites based on GPS signals received from a plurality of GPS satellites, and a moving speed of the moving object. Based on the orbit information of the GPS satellites contained in each of the GPS signals, and a predicted position calculating means for recognizing the moving direction and calculating the predicted position of the moving object based on the moving speed and the moving direction. Predicted pseudo-range calculating means for calculating a predicted pseudo-range between the predicted position of the moving object and each of the GPS satellites; and comparing the measured pseudo-range and the predicted pseudo-range for each of the GPS satellites. And a positioning possibility determining unit for determining whether to calculate the current position of the moving object based on the moving object.
[0007]
The invention according to claim 4 is a measurement pseudo distance calculating means for calculating a measurement pseudo distance between a moving object and each of the GPS satellites based on GPS signals received from a plurality of GPS satellites, and a moving speed of the moving object. Based on the orbit information of the GPS satellites contained in each of the GPS signals, and a predicted position calculating means for recognizing the moving direction and calculating the predicted position of the moving object based on the moving speed and the moving direction. Predicted pseudo-range calculating means for calculating a predicted pseudo-range between the predicted position of the moving object and each of the GPS satellites; and comparing the measured pseudo-range and the predicted pseudo-range for each of the GPS satellites. A most probable pseudo-range determining means for determining a most probable pseudo-range based on the current position, and a current position calculating means for calculating a current position of the moving object based on orbit information of the GPS satellite and each of the most probable pseudo-ranges; To provide a positioning device of a mobile, characterized in that it includes.
[0008]
According to a twelfth aspect of the present invention, there is provided a measurement pseudo distance calculating step of calculating a measurement pseudo distance between a moving object and each of the GPS satellites based on GPS signals received from a plurality of GPS satellites, and a moving speed of the moving object. A predicted position calculating step of calculating a predicted position of the moving object based on the moving speed and the moving direction; and, based on orbit information of the GPS satellites included in each of the GPS signals, A predicted pseudo distance calculating step of calculating a predicted pseudo distance between the predicted position of the moving object and each of the GPS satellites; and comparing the measured pseudo distance and the predicted pseudo distance with respect to each of the GPS satellites. A determination step of determining whether or not to calculate a current position of the mobile object based on the determination of the current position of the mobile object.
[0009]
The invention according to claim 13 is a measurement pseudo distance calculating step of calculating a measurement pseudo distance between a moving object and each of the GPS satellites based on GPS signals received from a plurality of GPS satellites, and a moving speed of the moving object. A predicted position calculating step of calculating a predicted position of the moving object based on the moving speed and the moving direction; and, based on orbit information of the GPS satellites included in each of the GPS signals, A predicted pseudo distance calculating step of calculating a predicted pseudo distance between the predicted position of the moving object and each of the GPS satellites; and comparing the measured pseudo distance and the predicted pseudo distance with respect to each of the GPS satellites. A most probable pseudo-range determining step of determining a most probable pseudo-range based on the current position; and a current position calculating step of calculating a current position of the mobile unit based on orbit information of the GPS satellite and each of the most probable pseudo-ranges. To provide a positioning method for a mobile body comprising a.
[0010]
According to a fourteenth aspect of the present invention, a computer included in a positioning device for a moving object is configured to calculate a pseudo distance between the moving object and each of the GPS satellites based on GPS signals received from a plurality of GPS satellites. Distance calculation means; recognition means for recognizing a moving speed and a moving direction of the moving body, and a predicted position calculating means for calculating a predicted position of the moving body based on the moving speed and the moving direction; A predicted pseudo distance calculating means for calculating a predicted position of the mobile object and a predicted pseudo distance between each of the GPS satellites based on orbit information of the GPS satellites; A computer which functions as positioning availability determining means for comparing the predicted pseudo distance and determining whether to calculate the current position of the moving object based on the result. To provide over data program.
[0011]
According to a fifteenth aspect of the present invention, a computer included in a positioning apparatus for a mobile object calculates a measurement pseudo distance between the mobile object and each of the GPS satellites based on GPS signals received from a plurality of GPS satellites. Distance calculation means; recognition means for recognizing a moving speed and a moving direction of the moving body, and a predicted position calculating means for calculating a predicted position of the moving body based on the moving speed and the moving direction; and each of the GPS signals. A predicted pseudo distance calculating means for calculating a predicted position of the mobile object and a predicted pseudo distance between each of the GPS satellites based on orbit information of the GPS satellites; A most probable pseudo distance determining means for comparing the predicted pseudo distance with the predicted pseudo distance, and determining the most probable pseudo distance based on the result; and Current position calculating means for calculating a current position of the body, provides a computer program for causing to function with.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
A preferred embodiment of the present invention will be described with reference to the drawings. Each embodiment described below is an embodiment in which the present invention is applied to an in-vehicle navigation device.
[0013]
[First Embodiment]
First, the configuration and functions of a vehicle-mounted navigation device according to a first embodiment of the present invention will be described with reference to FIG.
[0014]
FIG. 1 is a schematic block diagram of an in-vehicle navigation device. As shown in FIG. 1, the in-vehicle navigation device 1 receives a GPS signal transmitted from a GPS satellite, acquires information necessary for positioning, and controls a GPS receiver 2 for calculating a positioning position, and each unit. The control unit 3 includes an operation unit 4 for receiving a user's instruction, a map information acquisition unit 5 for reading and acquiring map information stored in a CD-ROM or the like, and a display unit 6 for displaying positioning results and the like. I have.
[0015]
The GPS receiver 2 includes a receiving antenna for receiving a GPS signal, a frequency conversion / amplification unit for frequency-converting and further amplifying the received GPS signal, a demodulation unit for demodulating the GPS signal, a CPU for performing calculations, and a primary storage unit for data and the like. It has the same components as a known GPS receiver, such as a RAM to be used and a ROM storing a computer program and the like. The computer program stored in the ROM allows the CPU to measure the pseudo distance calculation unit, the predicted position calculation unit, the predicted position calculation unit, and the like. It is made to function as distance calculation means, most probable pseudo distance determination means, and current position calculation means.
[0016]
The control unit 3 includes a CPU, a RAM, a ROM, and the like, and controls the GPS receiver 2, the operation unit 4, the map information acquisition unit 5, the display unit 6, and the like. Specifically, in accordance with an instruction from the operation unit 4, the GPS receiver 2 is operated to measure the current position, and the positioning result is displayed on the display unit 6 together with the map information acquired from the map information acquisition unit 5. .
[0017]
The operation unit 4 includes, for example, a touch panel, and a user performs various instructions and environment settings using the operation unit 4.
[0018]
The map information acquisition unit 5 is, for example, a known CD-ROM playback device, and reads map information and the like stored in a CD-ROM or the like and outputs the map information or the like to the control unit 3.
[0019]
The display unit 6 includes, for example, a liquid crystal display device, and displays the positioning result of the GPS receiver 2. As described above, the positioning result is displayed by, for example, displaying the own vehicle mark at a corresponding position on the map displayed based on the map information data output from the map information obtaining unit 5.
[0020]
First, with reference to FIG. 2, a description will be given of a characteristic part of the positioning in the vehicle-mounted navigation device 1.
[0021]
As shown in FIG. 2, a GPS signal is received from a GPS satellite S at a satellite position S2, and a measured pseudorange is calculated based on the GPS signal. In the case of FIG. 2, since the GPS signal is reflected by the building B before being received by the GPS receiver, the measured pseudo distance calculated based on the GPS signal is calculated as a distance longer than the regular distance. Is done.
[0022]
On the other hand, the moving speed and the moving direction of the own vehicle from the own vehicle position P at the time of the previous positioning are detected, and the predicted position N of the own vehicle at the time of the current positioning is calculated. Further, the satellite position S2 at the time of the current positioning is calculated from the orbit information (ephemeris) included in the GPS signal. Then, the distance between the predicted position N and the satellite position S2 is calculated as a predicted pseudo distance.
[0023]
Next, the measured pseudo distance is compared with the predicted pseudo distance, and based on the comparison result, 1) it is determined whether or not to calculate the current position of the vehicle, or 2) the most probable pseudo distance is determined. Then, the current position of the own vehicle is calculated based on the most probable pseudorange and the trajectory information included in the GPS signal. That is, when the difference between the measured pseudo-range and the predicted pseudo-range is large, there is a possibility that a large error is included in the measured pseudo-range. Therefore, 1) the calculation of the current position is stopped, and 2) the measured pseudo-range. For example, the current position is calculated based on the most probable pseudo distance corrected for.
[0024]
Next, a positioning processing procedure in the vehicle-mounted navigation device 1 will be described in detail with reference to FIG.
[0025]
The in-vehicle navigation device 1 starts positioning when an instruction of “positioning start” is input from the operation unit 4.
[0026]
Step 1 is a step in which the GPS receiver 2 receives a GPS signal from a GPS satellite. The GPS receiver 2 selects three to four or more catchable GPS satellites from a plurality of GPS satellites launched in outer space, and simultaneously receives GPS signals transmitted from these GPS satellites. Further, the GPS receiver 2 records the time (reception time) when the GPS signal was received. Note that the GPS signal includes time information such as the transmission time of the GPS signal, information on the orbit of the GPS satellite (orbit information), and the like.
[0027]
Step 2 is a step in which the GPS receiver 2 calculates a measured pseudorange. The GPS receiver 2 extracts time information from the GPS signal received in step 1 and specifies the transmission time of the GPS signal. Then, from the transmission time and the reception time recorded in step 1, a time (propagation time) from the transmission of the GPS signal by the GPS satellite to the reception by the GPS receiver 2 is calculated. Further, the propagation time is multiplied by the propagation speed (light speed) of the GPS signal to calculate a measurement pseudo distance which is a measurement distance between the GPS satellite and the GPS receiver 2. Note that this measurement pseudorange may include various errors such as an error due to reflection of a GPS signal to a building or the like.
[0028]
Step 3 is a step of calculating the predicted position of the own vehicle at the time of the current positioning from the moving speed and the moving direction of the own vehicle. From the GPS signal received in the previous positioning, the moving speed and moving direction of the own vehicle are specified. Further, the elapsed time from the previous positioning to the current positioning is calculated. Based on the moving speed, the moving direction, and the elapsed time obtained in this manner, the own vehicle relative position at the current positioning with respect to the own vehicle position at the previous positioning is calculated. Then, the own vehicle relative position is added to the own vehicle position at the time of the previous positioning, and the own vehicle predicted position at the current positioning is calculated.
[0029]
Step 4 is a step of calculating a predicted pseudo distance. The orbit information is read from the GPS signal received in step 1, and the satellite position of the GPS satellite at the time of the current positioning is specified from the orbit information. Then, the distance between the two points of the satellite position and the predicted position of the own vehicle at the time of the current positioning calculated in step 3 is calculated as the predicted pseudo distance.
[0030]
Step 5 is a step of determining a reference value (error reference value) for error determination. The error reference value is a reference value used as a measure when comparing the measured pseudo distance and the predicted pseudo distance in step 6. That is, the difference between the measured pseudo distance and the predicted pseudo distance is compared with the error reference value. If the distance difference exceeds the error reference value, the error included in the measured pseudo distance is large, and if not, the error is small. This is a reference value for determination.
[0031]
This error reference value is determined based on the elapsed time from the previous positioning to the current positioning. That is, when the elapsed time is long, the reliability of the predicted position of the vehicle, which is calculated based on the moving speed and the moving direction of the vehicle, and thus the reliability of the predicted pseudo distance is low. To make the determination, the error reference value is set large. On the other hand, when the elapsed time is short, the reliability of the predicted pseudo distance increases, and the error reference value is set to a small value because the determination is made with emphasis on the predicted pseudo distance. Here, the elapsed time refers to the elapsed time from the previous positioning, which was able to calculate the positioning result. That is, there are cases where satellites cannot be acquired or positioning results cannot be obtained due to errors, but these positionings are not considered.
[0032]
Step 6 is a step of comparing the measured pseudo distance and the predicted pseudo distance to determine an error included in the measured pseudo distance. As described above, by comparing the difference between the measured pseudo distance and the predicted pseudo distance and the error reference value, the measured pseudo distance and the predicted pseudo distance are compared, and when the distance difference exceeds the error reference value, the measurement is performed. It is determined that the error included in the pseudo distance is large, and if not, the error is small.
[0033]
Step 7 is a step of determining the most probable pseudorange. The most probable pseudo distance is determined based on the result of the determination in step 6. For example, if it is determined in step 6 that the error of the measured pseudo distance is small, the measured pseudo distance is set as the most probable pseudo distance (step 7A). The distance is set (step 7B). When it is determined that the error of the measured pseudorange is large, the determined pseudorange is determined to be unmeasurable, and the following steps are performed based on the determined pseudoranges of the GPS satellites other than the GPS satellite determined to be unmeasurable. In step 8, the current position may be calculated.
[0034]
Step 8 is a step of calculating the current position of the own vehicle. For each GPS satellite captured in step 1, the most probable pseudorange and satellite position are determined as a result of each of the above steps. Then, a spherical surface having the radius of the most probable pseudo distance centered on the satellite position is set for each GPS satellite. Each spherical surface obtained in this way includes the current position of the vehicle, and by calculating the intersection of these spherical surfaces, the current position of the vehicle can be calculated.
[0035]
At this time, for example, when a GPS signal is received from a GPS satellite and a GPS satellite can be selected to calculate the current position, the GPS satellite determined to have a large error included in the measured pseudo distance in step 6 is determined. May not be used, and the current position may be calculated based only on the most probable pseudorange of a GPS satellite determined to have a small error included in the measured pseudorange.
[0036]
Steps 1 to 8 are repeated until the operation section 4 gives an instruction of "positioning end", and the positioning is ended when the instruction of "positioning end" is issued (step 9).
[0037]
In the above description, the most probable pseudo distance is determined based on the comparison result between the measured pseudo distance and the predicted pseudo distance.However, the current position is calculated based on the comparison result between the measured pseudo distance and the predicted pseudo distance. You may decide whether or not. In this case, the steps 7 and 8 are replaced with the next step 10.
[0038]
That is, step 10 is a step of determining whether or not to calculate the current position of the own vehicle based on the determination result of step 6. That is, when it is determined in step 6 that the error of the measured pseudo distance is small, the current position of the own vehicle is calculated based on the measured pseudo distance and the track information, and when it is determined that the error of the measured pseudo distance is large. Does not calculate the current position of the own vehicle, and returns to step 1 to continue the processing if the instruction of “end of positioning” is not issued in the subsequent step 9. If it is determined in step 10 that the error of the measured pseudo-range is small and it is determined that the current position of the vehicle is to be calculated, the processing in steps 7 and 8 may be performed subsequently. In this case, the error reference value is determined in two stages, large and small, and the larger reference value is used as the error reference value when determining whether or not to calculate the current position of the vehicle, and the most probable pseudo distance is determined. The smaller reference value may be used as the error reference value at the time of execution. That is, when the distance difference between the measured pseudo distance and the predicted pseudo distance is extremely large, the calculation of the current position is stopped. When the distance difference is relatively large, the predicted pseudo distance is determined as the most probable pseudo distance, and when the distance difference is small, The measurement proceeding distance may be determined as the most probable pseudo distance. As a result, a more reliable calculation of the current position can be performed.
[0039]
As described above, the in-vehicle navigation device 1 according to the first embodiment calculates the measured pseudo distance between the own vehicle and each GPS satellite based on the GPS signals received from the plurality of GPS satellites, and A predicted pseudo distance is calculated based on the predicted vehicle position calculated based on the moving speed and the moving direction and a satellite position obtained from orbit information (ephemeris) included in each GPS signal, and the measured pseudo distance and the predicted pseudo distance are calculated. The distance is compared with the distance, and based on the result, 1) it is determined whether or not to calculate the current position of the vehicle, or 2) the most probable pseudo distance is determined, and the most probable pseudo distance and the track information are determined. The current position of the own vehicle is calculated based on the satellite position obtained from. According to this, it is possible to determine whether or not the positioning pseudo-range includes a large error by comparing the positioning pseudo-range with the predicted pseudo-range that relatively does not include a large error, and based on the determination result, Since the current position of the car is calculated, the reliability of the positioning can be improved.
[0040]
Further, the moving speed and the moving distance of the own vehicle are specified based on the GPS signal. According to this, it is possible to specify the moving speed and the moving distance of the own vehicle without particularly using other measuring devices.
[0041]
The comparison between the measured pseudo distance and the predicted pseudo distance is determined based on whether or not the distance difference between the measured pseudo distance and the predicted pseudo distance exceeds an error reference value. According to this, both can be compared uniformly, and the judgment level can be easily changed (adjusted) by manipulating the error reference value.
[0042]
Further, the above-described error reference value is determined based on the elapsed time from the previous positioning to the current positioning. According to this, when the elapsed time is short, the reliability of the predicted pseudo distance is high, so that the error reference value is reduced, and the error determination of the positioning pseudo distance emphasizing the predicted pseudo distance can be performed. Since the reliability of the predicted pseudorange is low, the error reference value can be increased to determine the error of the positioning pseudorange with emphasis on the measured pseudorange.
[0043]
[Second embodiment]
The second embodiment is an embodiment of an in-vehicle navigation device using a vehicle speed sensor and a gyro sensor for calculating the speed and direction of the own vehicle.
[0044]
First, the configuration and functions of a vehicle-mounted navigation device according to a second embodiment of the present invention will be described with reference to FIG.
[0045]
FIG. 4 is a schematic block diagram of the on-vehicle navigation device. As shown in FIG. 4, the in-vehicle navigation device 11 is configured by adding a vehicle speed sensor 17 and a gyro sensor 18 to the in-vehicle navigation device according to the first embodiment.
[0046]
The vehicle speed sensor 17 constitutes a moving speed detecting means, and detects the moving speed of the own vehicle from a vehicle speed pulse generated as the wheels rotate. The gyro sensor 18 constitutes a moving direction detecting means, and detects the moving direction of the own vehicle from the angular velocity at the time of changing the direction of the own vehicle. The vehicle speed sensor 17 and the gyro sensor 18 are connected to the GPS receiver 2 and transmit the detected moving speed and moving direction to the GPS receiver 2 respectively. The GPS receiver 2 calculates a predicted position of the own vehicle based on the transmitted moving speed and moving direction.
[0047]
The other components of the on-vehicle navigation device 11 have the same functions as those of the first embodiment, and thus are denoted by the same reference numerals and description thereof will be omitted.
[0048]
Next, the positioning processing procedure in the in-vehicle navigation device 11 will be described. However, the positioning processing procedure in the second embodiment differs from the positioning processing procedure in the first embodiment only in step 3, and thus step 3 will be described below.
[0049]
Step 3 is a step of calculating the predicted position of the vehicle at the time of the current positioning from the moving speed and the moving direction of the vehicle, which is the moving body, as in the first embodiment. In the second embodiment, the predicted position of the vehicle at the time of the current positioning is calculated based on the moving speed of the vehicle detected by the vehicle speed sensor 17 and the moving direction of the vehicle detected by the gyro sensor 18. That is, the vehicle speed sensor 17 detects a vehicle speed pulse generated with the rotation of the wheels of the own vehicle, specifies the moving speed of the own vehicle based on the detected pulse, and transmits the movement speed to the GPS receiver 2. In addition, the gyro sensor 18 detects the angular velocity at the time of the direction change of the own vehicle, specifies the moving azimuth of the own vehicle based on the angular velocity, and transmits it to the GPS receiver 2. The GPS receiver 2 calculates a predicted position of the own vehicle at the time of the current positioning from the transmitted moving speed and moving direction of the own vehicle.
[0050]
The other steps are the same as in the first embodiment, and a description thereof will be omitted.
[0051]
As described above, the in-vehicle navigation device 11 according to the second embodiment differs from the in-vehicle navigation device 1 according to the first embodiment in that the vehicle speed sensor 17 as a traveling speed detecting unit detects the traveling speed of the own vehicle. In addition, the gyro sensor 18 as a moving direction detecting means detects the moving direction of the own vehicle. According to this, it is possible to more accurately specify the moving speed and the moving direction of the own vehicle, and the reliability of the positioning is further improved.
[0052]
[Other embodiments]
The in-vehicle navigation device according to each of the embodiments described above uses a computer included in the GPS receiver to execute a measurement pseudo distance calculation unit, a predicted position calculation unit, a predicted pseudo distance calculation unit, a most probable pseudo distance by a computer program stored in a ROM. Although it has been made to function as the determination means, the current position calculation means or the positioning possibility determination means, the CPU included in the control unit may be made to function as each of the above means by a computer program stored in the ROM.
[0053]
Further, in each of the above embodiments, the in-vehicle navigation device has been described, but the present invention is not limited to this, and can be applied to, for example, a portable navigation device. In the case of a portable navigation device, for example, a speed sensor using a pedometer (registered trademark) that measures the distance by the number of steps may be used as the moving speed detecting unit instead of the vehicle speed sensor in the second embodiment.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram of a vehicle-mounted navigation device according to a first embodiment.
FIG. 2 is a diagram illustrating a positioning process in the mounted navigation device.
FIG. 3 is a flowchart of a positioning processing procedure in the on-vehicle navigation device according to the first embodiment.
FIG. 4 is a schematic block diagram of an in-vehicle navigation device according to a second embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 In-vehicle navigation device 2 GPS receiver 3 Control part 4 Operation part 5 Map information acquisition part 6 Display part

Claims

Measurement pseudo-distance calculating means for calculating a measurement pseudo-distance between a moving object and each of the GPS satellites based on GPS signals received from a plurality of GPS satellites;
Predicted position calculating means for recognizing a moving speed and a moving direction of the moving body and calculating a predicted position of the moving body based on the moving speed and the moving direction,
Predicted pseudo-distance calculation means for calculating a predicted pseudo-distance between the mobile object and each of the GPS satellites, based on orbit information of the GPS satellites included in each of the GPS signals,
Positioning feasibility determining means for comparing the measured pseudo-range and the predicted pseudo-range for each of the GPS satellites, and determining whether to calculate the current position of the moving object based on the result. A mobile positioning device, comprising:

The positioning availability determination means calculates a distance difference that is a difference between the measured pseudo distance and the predicted pseudo distance, and calculates a current position of the moving body based on whether the distance difference exceeds a predetermined reference value. The mobile positioning apparatus according to claim 1, wherein whether to perform the determination is determined.

The positioning apparatus according to claim 2, wherein the reference value used in the positioning determination unit is determined based on an elapsed time from a previous positioning to a current positioning.

Measurement pseudo-distance calculating means for calculating a measurement pseudo-distance between a moving object and each of the GPS satellites based on GPS signals received from a plurality of GPS satellites;
Predicted position calculating means for recognizing a moving speed and a moving direction of the moving body and calculating a predicted position of the moving body based on the moving speed and the moving direction,
Predicted pseudo-distance calculation means for calculating a predicted pseudo-distance between the mobile object and each of the GPS satellites, based on orbit information of the GPS satellites included in each of the GPS signals,
For each of the GPS satellites, comparing the measured pseudo-range and the predicted pseudo-range, determining a most probable pseudo-range based on the result,
And a current position calculating means for calculating a current position of the moving object based on the orbit information of the GPS satellite and each of the most probable pseudo distances.

The most probable pseudo distance determining means calculates a distance difference that is a difference between the measured pseudo distance and the predicted pseudo distance, and determines the most probable pseudo distance based on whether the distance difference exceeds a predetermined reference value. The moving object positioning apparatus according to claim 4, wherein:

The positioning device according to claim 5, wherein the most probable pseudo distance determining means sets the measured pseudo distance as the most probable pseudo distance when the distance difference does not exceed the reference value. .

The positioning of a moving object according to claim 5, wherein the most probable pseudo distance determining means determines the predicted pseudo distance as the most probable pseudo distance when the distance difference exceeds the reference value. apparatus.

The current position calculation means determines that the most probable pseudo distance for a GPS satellite whose distance difference exceeds the reference value is unusable, and calculates a current position based on the most probable pseudo distance for another GPS satellite. The mobile positioning device according to claim 5 or 6, wherein

The moving object according to any one of claims 5 to 8, wherein the reference value used in the most probable pseudo distance determination means is determined based on an elapsed time from a previous positioning to a current positioning. Positioning device.

11. The apparatus according to claim 1, wherein the predicted position calculating unit calculates a predicted position of the moving body by recognizing a moving speed and a moving direction of the moving body based on the GPS signal. A positioning device for a mobile object according to the paragraph.

Further, a moving speed detecting means for detecting a moving speed of the moving body, and a moving direction detecting means for detecting a moving direction of the moving body,
2. The predicted position calculating unit calculates a predicted position of the moving body by recognizing a moving speed and a moving azimuth of the moving body by the moving speed detecting unit and the moving azimuth detecting unit. The mobile positioning device according to any one of claims 10 to 10.

A measurement pseudo-distance calculating step of calculating a measurement pseudo-distance between a mobile object and each of the GPS satellites based on GPS signals received from a plurality of GPS satellites;
A predicted position calculating step of recognizing a moving speed and a moving direction of the moving body and calculating a predicted position of the moving body based on the moving speed and the moving direction;
A predicted pseudo-range calculating step of calculating a predicted position of the moving object and a predicted pseudo-range between each of the GPS satellites based on orbit information of the GPS satellites included in each of the GPS signals;
A positioning feasibility determining step of comparing the measured pseudo distance with the predicted pseudo distance for each of the GPS satellites, and determining whether to calculate the current position of the moving object based on the result. A positioning method for a moving object, comprising:

A measurement pseudo-distance calculating step of calculating a measurement pseudo-distance between a mobile object and each of the GPS satellites based on GPS signals received from a plurality of GPS satellites;
A predicted position calculating step of recognizing a moving speed and a moving direction of the moving body and calculating a predicted position of the moving body based on the moving speed and the moving direction;
A predicted pseudo-range calculating step of calculating a predicted position of the moving object and a predicted pseudo-range between each of the GPS satellites based on orbit information of the GPS satellites included in each of the GPS signals;
For each of the GPS satellites, comparing the measured pseudo-range with the predicted pseudo-range, and determining a most probable pseudo-range based on the result,
A current position calculating step of calculating a current position of the moving object based on the orbit information of the GPS satellite and each of the most probable pseudoranges.

A computer included in the mobile positioning device,
Measurement pseudo-distance calculating means for calculating a measurement pseudo-distance between a moving object and each of the GPS satellites based on GPS signals received from a plurality of GPS satellites;
Predicted position calculating means for recognizing a moving speed and a moving direction of the moving body and calculating a predicted position of the moving body based on the moving speed and the moving direction,
Predicted pseudo-distance calculation means for calculating a predicted pseudo-distance between the mobile object and each of the GPS satellites, based on orbit information of the GPS satellites included in each of the GPS signals,
Positioning feasibility determining means for comparing the measured pseudo-range and the predicted pseudo-range for each of the GPS satellites and determining whether or not to calculate the current position of the moving object based on the result; A computer program characterized by causing a computer to function.

A computer included in the mobile positioning device,
Measurement pseudo-distance calculating means for calculating a measurement pseudo-distance between a moving object and each of the GPS satellites based on GPS signals received from a plurality of GPS satellites;
Predicted position calculating means for recognizing a moving speed and a moving direction of the moving body and calculating a predicted position of the moving body based on the moving speed and the moving direction,
Predicted pseudo-distance calculation means for calculating a predicted pseudo-distance between the mobile object and each of the GPS satellites, based on orbit information of the GPS satellites included in each of the GPS signals,
For each of the GPS satellites, comparing the measured pseudo-range and the predicted pseudo-range, determining a most probable pseudo-range based on the result,
A computer program functioning as current position calculating means for calculating a current position of the moving object based on orbit information of the GPS satellite and each of the most probable pseudoranges.