JP2004309227A - Measuring instrument, azimuth measuring instrument, calibration program and calibration method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and accurately correct the sensitivity of a magnetic sensor and to easily correct the offset of the magnetic sensor while reducing cost. <P>SOLUTION: This measuring instrument is constituted to acquire triaxial output when the direction of the triaxial magnetic sensor 11 is changed in a three-dimensional space, by repeating prescribed times or more, to determine ellipsoids with each main axis parallel with each coordinate axis of a rectangular coordinate system (x, y, z), on the rectangular coordinate system (x, y, z), to arrange repeatedly acquired measured data on the rectangular coordinate system (x, y, z) and to compute sensitivity correction factors αx, αy, αz and offsets Crx, Cry, Crz which are the center coordinates of the ellipsoids by a statistical method to minimize a distance between each arranged measuring point and the ellipsoid. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００７０】
【数２】

【００７１】
【数３】

【００７２】
ただし、ａｘは、ｘ軸ホール素子ＨＥｘの感度［Ｖ／Ｔ］、Ｃｒｘは、ｘ軸ホール素子ＨＥｘのオフセット［Ｖ］、ａｙは、ｙ軸ホール素子ＨＥｙの感度［Ｖ／Ｔ］、Ｃｒｙは、ｙ軸ホール素子ＨＥｙのオフセット［Ｖ］、ａｚは、ｚ軸ホール素子ＨＥｚの感度［Ｖ／Ｔ］、Ｃｒｚは、ｚ軸ホール素子ＨＥｚのオフセット［Ｖ］、Ｍｘは、地磁気Ｍのｘ方向成分［Ｔ］、Ｍｙは、地磁気Ｍのｙ方向成分［Ｔ］、Ｍｚは、地磁気Ｍのｚ方向成分［Ｔ］である。
【００７３】
そして、オフセット情報記憶部１９ａには、ｘ軸ホール素子ＨＥｘ、ｙ軸ホール素子ＨＥｙおよびｚ軸ホール素子ＨＥｚのオフセットがそれぞれオフセット情報として記憶されるとともに、感度補正情報記憶部１９ｂには、ｘ軸ホール素子ＨＥｘ、ｙ軸ホール素子ＨＥｙおよびｚ軸ホール素子ＨＥｚのばらつきを補正するための感度補正係数がそれぞれ感度補正情報として記憶される。
【００７４】
方位角計測実行中は、補正計算部１６は、これらのオフセット情報および感度補正情報を用いることにより、ｘ軸ホール素子ＨＥｘ、ｙ軸ホール素子ＨＥｙおよびｚ軸ホール素子ＨＥｚの出力増幅値Ｓｒｘ、Ｓｒｙ、Ｓｒｚをそれぞれ補正し、地磁気Ｍのｘ、ｙ、ｚ軸成分Ｍｘ、Ｍｙ、Ｍｚだけを取り出し、方位角計算部１７に出力する。
【００７５】
そして、方位角計算部１７は、地磁気Ｍのｘ、ｙ、ｚ軸成分Ｍｘ、Ｍｙ、Ｍｚの符号と、θ＝ｔａｎ^−１（Ｍｙ／Ｍｘ）の式に基づいて、方位角θを算出する。
キャリブレーション実行中は、ｘ軸ホール素子ＨＥｘ、ｙ軸ホール素子ＨＥｙおよびｚ軸ホール素子ＨＥｚの各出力増幅値Ｓｒｘ、Ｓｒｙ、Ｓｒｚは、オフセット・感度補正係数算出部１８に出力される。
【００７６】
オフセット・感度補正係数算出部１８は、携帯機器２０１の向きが３次元空間において任意に変化している時に、ｘ軸ホール素子ＨＥｘ、ｙ軸ホール素子ＨＥｙおよびｚ軸ホール素子ＨＥｚの各出力増幅値Ｓｒｘ、Ｓｒｙ、Ｓｒｚを所定回数以上取得し、取得した出力増幅値Ｓｒｘ、Ｓｒｙ、Ｓｒｚに基づいて、ｘ軸ホール素子ＨＥｘ、ｙ軸ホール素子ＨＥｙおよびｚ軸ホール素子ＨＥｚの感度補正係数およびオフセットをそれぞれ算出し、算出した感度補正係数を感度補正情報記憶部１９ｂに、算出したオフセットをオフセット情報記憶部１９ａにそれぞれ格納する。
次に、感度補正係数およびオフセットの算出方法を説明する。
まず、感度補正係数を下式（８）により定義する。
【００７７】
【数４】

【００７８】
ただし、αｘは、ｘ軸ホール素子ＨＥｘの感度補正係数、αｙは、ｙ軸ホール素子ＨＥｙの感度補正係数、αｚは、ｚ軸ホール素子ＨＥｚの感度補正係数、ａ０は、感度補正後の３軸磁気センサ１１の感度［Ｖ／Ｔ］である。
さらに、感度補正後の３軸磁気センサ１１の出力増幅値およびオフセットを下式（９）〜（１４）により定義する。
【００７９】
【数５】

【００８０】
【数６】

【００８１】
【数７】

【００８２】
【数８】

【００８３】
【数９】

【００８４】
【数１０】

【００８５】
ただし、Ｓｘは、ｘ軸ホール素子ＨＥｘの感度補正後の出力増幅値［Ｖ］、Ｃｘは、ｘ軸ホール素子ＨＥｘの感度補正後のオフセット［Ｖ］、Ｓｙは、ｙ軸ホール素子ＨＥｙの感度補正後の出力増幅値［Ｖ］、Ｃｙは、ｙ軸ホール素子ＨＥｙの感度補正後のオフセット［Ｖ］、Ｓｚは、ｚ軸ホール素子ＨＥｚの感度補正後の出力増幅値［Ｖ］、Ｃｚは、ｚ軸ホール素子ＨＥｚの感度補正後のオフセット［Ｖ］である。
上式（９）〜（１４）を上式（５）〜（７）に代入すると、下式（１５）〜（１７）が得られる。
【００８６】
【数１１】

【００８７】
【数１２】

【００８８】
【数１３】

【００８９】
一方、地磁気は、下式（１８）により定義される。
【００９０】
【数１４】

【００９１】
ただし、Ｍは、地磁気［Ｔ］である。
キャリブレーション実行中は、携帯機器２０１の向きだけが変わり場所の移動がないのであれば、地磁気Ｍは、一定値として見なせる。したがって、上式（１５）〜（１７）を変形して上式（１８）に代入すると、下式（１９）が得られる。
【００９２】
【数１５】

【００９３】
すなわち、直交座標系（ｘ，ｙ，ｚ）において点（Ｓｘ，Ｓｙ，Ｓｚ）は、常に点（Ｃｘ，Ｃｙ，Ｃｚ）から一定の距離ａ０Ｍをおいて位置することになる。
図３は、キャリブレーション方法の概念を説明する図である。
図３において、携帯機器２０１の向きを任意の様々な方向に向けながら地磁気ＭをＮ回測定して取得された測定データを、ｘ軸ホール素子ＨＥｘの感度補正前の出力増幅値については、Ｓ１ｒｘ，Ｓ２ｒｘ，…，ＳＮｒｘ［Ｖ］とし、ｙ軸ホール素子ＨＥｙの感度補正前の出力増幅値については、Ｓ１ｒｙ，Ｓ２ｒｙ，…，ＳＮｒｙ［Ｖ］とし、ｚ軸ホール素子ＨＥｚの感度補正前の出力増幅値については、Ｓ１ｒｚ，Ｓ２ｒｚ，…，ＳＮｒｚ［Ｖ］とする。さらに、これらの値で特定される測定点Ｐ１（Ｓ１ｒｘ，Ｓ１ｒｙ，Ｓ１ｒｚ），Ｐ２（Ｓ２ｒｘ，Ｓ２ｒｙ，Ｓ２ｒｚ），…，ＰＮ（ＳＮｒｘ，ＳＮｒｙ，ＳＮｒｚ）を直交座標系（ｘ，ｙ，ｚ）にそれぞれ配置する。
【００９４】
感度補正係数αｘ，αｙ，αｚが既知であると仮定し、直交座標系（ｘ，ｙ，ｚ）の各軸について下式（２０）〜（２２）のスケーリングを行ったとすると、直交座標系（ｘ，ｙ，ｚ）において測定点Ｐ１，Ｐ２，…，ＰＮは、スケーリング後の直交座標系（ｘ’，ｙ’，ｚ’）において下式（２３）〜（２５）に示すように変換される。
【００９５】
【数１６】

【００９６】
【数１７】

【００９７】
【数１８】

【００９８】
【数１９】

【００９９】
【数２０】

【０１００】
【数２１】

【０１０１】
ただし、Ｓ１ｘ，Ｓ２ｘ，…，ＳＮｘは、下式（２６）により得られ、Ｓ１ｙ，Ｓ２ｙ，…ＳＮｙは、下式（２７）により得られ、Ｓ１ｚ，Ｓ２ｚ，…ＳＮｚは、下式（２８）により得られる。
【０１０２】
【数２２】

【０１０３】
【数２３】

【０１０４】
【数２４】

【０１０５】
ただし、Ｓ１ｘ，Ｓ２ｘ，…，ＳＮｘは、ｘ軸ホール素子ＨＥｘの感度補正後の出力増幅値［Ｖ］、Ｓ１ｙ，Ｓ２ｙ，…，ＳＮｙは、ｙ軸ホール素子ＨＥｙの感度補正後の出力増幅値［Ｖ］、Ｓ１ｚ，Ｓ２ｚ，…，ＳＮｚは、ｚ軸ホール素子ＨＥｚの感度補正後の出力増幅値［Ｖ］である。また、Ｍ１ｘ，Ｍ２ｘ，…，ＭＮｘは、地磁気のｘ軸方向の成分［Ｔ］、Ｍ１ｙ，Ｍ２ｙ，…，ＭＮｙは、地磁気のｙ軸方向の成分［Ｔ］、Ｍ１ｚ，Ｍ２ｚ，…，ＭＮｚは、地磁気のｚ軸方向の成分［Ｔ］である。
すると、上式（１８）により下式（２９）が得られ、上式（１９）により下式（３０）が得られる。
【０１０６】
【数２５】

【０１０７】
【数２６】

【０１０８】
すなわち、スケーリング後の直交座標系（ｘ’，ｙ’，ｚ’）において測定点Ｐ１’，Ｐ２’，…，ＰＮ’は、いずれも点（Ｃｘ，Ｃｙ，Ｃｚ）からみて一定の距離ａ０Ｍをおいて位置することになる。
さらに、上式（１２）〜（１４）および上式（２６）〜（２８）を変形して上式（３０）に代入すると、下式（３１）が得られる。
【０１０９】
【数２７】

【０１１０】
すなわち、直交座標系（ｘ，ｙ，ｚ）において測定点Ｐ１，Ｐ２，…，ＰＮは、いずれも各主軸が直交座標系（ｘ，ｙ，ｚ）の各座標軸に平行で、各主軸の長さがａ０Ｍ／αｘ，ａ０Ｍ／αｙ，ａ０Ｍ／αｚでかつ中心座標が（Ｃｒｘ，Ｃｒｙ，Ｃｒｚ）の楕円面上に位置することになる。
したがって、見方を変えれば次のことが言える。
【０１１１】
測定点Ｐ１，Ｐ２，…，ＰＮが直交座標系（ｘ，ｙ，ｚ）に分布しているとし、適当なスケーリングファクタαｘ，αｙ，αｚを設定して上式（２０）〜（２２）により直交座標系（ｘ，ｙ，ｚ）をスケーリングした結果、スケーリング後の直交座標系（ｘ’，ｙ’，ｚ’）において測定点Ｐ１’，Ｐ２’，…，ＰＮ’のすべてがある点（Ｃｘ，Ｃｙ，Ｃｚ）から等しい距離に位置するようになったとする。このとき、αｘ，αｙ，αｚが感度補正係数に、Ｃｘ，Ｃｙ，Ｃｚが感度補正後のオフセットに相当する。
【０１１２】
または、直交座標系（ｘ，ｙ，ｚ）において、各主軸が直交座標系（ｘ，ｙ，ｚ）の各座標軸に平行な楕円面を設定したとき、測定点Ｐ１，Ｐ２，…，ＰＮのすべてが楕円面上に位置するようになったとする。このとき、各主軸の長さは感度補正係数αｘ，αｙ，αｚ、感度補正後の磁気センサの感度α０および地磁気Ｍからなる係数ａ０Ｍ／αｘ，ａ０Ｍ／αｙ，ａ０Ｍ／αｚに相当し、中心座標は感度補正前のオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚに相当する。
【０１１３】
以上の考え方に基づいて、測定データから感度補正係数αｘ，αｙ，αｚおよびオフセットＣｘ，Ｃｙ，Ｃｚを算出する方法を導出することができる。なお、方位角計算において必要な情報は、地磁気のｘ，ｙ，ｚ軸方向成分相互の比であって絶対値ではないため、ａ０およびＭを算出する必要はなく、これまでの式にたびたび出てきたａ０Ｍには、計算に都合のよい任意の値を設定してよい。
【０１１４】
なお、以下の具体例では、数式の複雑化をなるべく避けるために、適宜Ｃｘ，Ｃｙ，Ｃｚ若しくはＣｒｘ，Ｃｒｙ，Ｃｒｚのいずれか一方の算出を行っているが、両者の関係は、上式（１２）〜（１４）の通りであり、意味は同じである。
３軸磁気センサ１１の出力増幅値に含まれる誤差がほとんど無視し得るものと仮定するならば、互いに異なる任意の６方向に携帯機器２０１を向け、それぞれ地磁気を測定すればよい。
【０１１５】
上式（３１）は、αｘ^２，αｙ^２，αｚ^２およびオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚに関する６次元の非線形連立方程式であり、解析的に解くことは困難であるが、数値計算（例えば、Ｎｅｗｔｏｎ−Ｒａｐｈｓｏｎ法）で解くことができる。
なお、下式（３２），（３３）とおいて上式（３１）を変形すると、下式（３４）に示すようなｐ，ｑおよびオフセットＣｘ，Ｃｙ，Ｃｚに関する５次元の非線形連立方程式を得ることができる。
【０１１６】
【数２８】

【０１１７】
【数２９】

【０１１８】
【数３０】

【０１１９】
上式（３４）は、上式（３１）と比べて次元が一つ少ないので計算量を少なくすることができる。
一方、注意しなければならないことは、実際に測定される地磁気の強度は、０．０１［ｍＴ］オーダーであり、非常に微弱であるため、３軸磁気センサ１１の出力増幅値には相当のノイズが含まれているということである。
【０１２０】
そのため、測定回数Ｎをなるべく大きくして、統計的手法を用いて感度補正係数αｘ，αｙ，αｚおよびオフセットＣｘ，Ｃｙ，Ｃｚの算出を行う必要があり、その具体例を以下に示す。
感度補正係数αｘ，αｙ，αｚおよびオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚが算出されたとして、スケーリング後の直交座標系（ｘ’，ｙ’，ｚ’）におけるｉ回目の測定データに対応する測定点Ｐｉ’（Ｓｉｘ，Ｓｉｙ，Ｓｉｚ）から点（Ｃｘ，Ｃｙ，Ｃｚ）までの距離ｄｉは、下式（３５）により得られる。
【０１２１】
【数３１】

【０１２２】
もし、測定データにノイズが含まれておらず、かつ、感度補正係数αｘ，αｙ，αｚおよびオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚの算出が正しく行われた場合は、すべての測定データについてｄｉ＝ａ０Ｍとなる。しかし、実際には測定データにノイズが含まれているため両者は等しくならない。そこで、ｉ回目の測定データに対する測定誤差および２乗総和を、下式（３６），（３７）により定義する。
【０１２３】
【数３２】

【０１２４】
【数３３】

【０１２５】
上式（１２）〜（１４）および上式（２６）〜（２８）を変形して上式（３７）に代入すると、下式（３８）が得られる。
【０１２６】
【数３４】

【０１２７】
この２乗総和Ｓが最小となるように、感度補正係数αｘ，αｙ，αｚおよびオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚを算出するのが算出方法として妥当である。
次に、２乗総和Ｓが最小となるように、感度補正係数αｘ，αｙ，αｚおよびオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚを算出する方法を説明する。
感度補正係数αｘ，αｙ，αｚおよびオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚのすべてを独立変数として、多次元最適化手法（例えば、共役勾配法）を用いて、上式（３８）のＳを最小にすることができる。なお、共役勾配法については、「Ｗ．Ｈ．Ｐｒｅｓｓ，Ｓ．Ａ．Ｔｅｕｋｏｌｓｋｙ，Ｗ．Ｔ．Ｖｅｔｔｅｒｌｉｎｇ ａｎｄ Ｂ．Ｐ．Ｆｌａｎｎｅｒｙ，”Ｎｕｍｅｒｉｃａｌ Ｒｅｃｉｐｉｅｓ ｉｎ Ｃ，Ｓｅｃｏｎｄ Ｅｄｉｔｉｏｎ”，Ｃａｍｂｒｉｄｇｅ Ｕｎｉｖｅｒｓｉｔｙ Ｐｒｅｓｓ，ＵＳＡ，１９９２，ｐｐ．４２０−４２５」に詳しい。
【０１２８】
多次元最適化手法として共役勾配法を用いる場合、各独立変数によるＳの導関数を計算する必要があるが、上式（３８）を、感度補正係数αｘ，αｙ，αｚおよびオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚでそれぞれ偏微分した下式（３９）〜（４４）を用いればよい。
【０１２９】
【数３５】

【０１３０】
【数３６】

【０１３１】
【数３７】

【０１３２】
【数３８】

【０１３３】
【数３９】

【０１３４】
【数４０】

【０１３５】
共役勾配法を用いた算出方法は、第２および第３の実施の形態における算出方法と比して手順が簡単であり、プログラムステップ数を抑えたい場合には好都合である。
次に、本実施の形態の動作を説明する。
キャリブレーションを行う場合は、携帯機器２０１を移動・回転等させることによりその向きを任意の方向に変化させると、オフセット・感度補正係数算出部１８により、３軸磁気センサ１１の向きが３次元空間において変化した時の３軸出力が所定回数以上繰り返して取得される。次いで、直交座標系（ｘ，ｙ，ｚ）上に、各主軸が直交座標系（ｘ，ｙ，ｚ）の各座標軸に平行な楕円面を定め、繰り返し取得された測定データが直交座標系（ｘ，ｙ，ｚ）上に配置され、配置された各測定点と楕円面との距離が最小となるように、楕円面の各主軸の長さおよび中心座標が統計的手法によって算出される。具体的には、共役勾配法により上式（３８）のＳを最小にして、感度補正係数αｘ，αｙ，αｚおよび楕円面の中心座標であるオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚが算出される。そして、算出された感度補正係数αｘ，αｙ，αｚは、感度補正情報記憶部１９ｂに、算出されたオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚは、オフセット情報記憶部１９ａにそれぞれ格納される。
【０１３６】
方位角を計測する場合は、補正計算部１６により、感度補正情報記憶部１９ｂの感度補正係数αｘ，αｙ，αｚおよびオフセット情報記憶部１９ａのオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚに基づいて、ｘ軸ホール素子ＨＥｘ、ｙ軸ホール素子ＨＥｙおよびｚ軸ホール素子ＨＥｚの出力増幅値Ｓｒｘ、Ｓｒｙ、Ｓｒｚがそれぞれ補正され、地磁気Ｍのｘ、ｙ、ｚ軸成分Ｍｘ、Ｍｙ、Ｍｚだけが取り出され、方位角計算部１７に出力される。そして、方位角計算部１７により、地磁気Ｍのｘ、ｙ、ｚ軸成分Ｍｘ、Ｍｙ、Ｍｚの符号と、θ＝ｔａｎ^−１（Ｍｙ／Ｍｘ）の式に基づいて、方位角θが算出される。
【０１３７】
このようにして、本実施の形態では、３軸磁気センサ１１の向きが３次元空間において変化した時の３軸出力を所定回数以上繰り返して取得し、直交座標系（ｘ，ｙ，ｚ）上に、各主軸が直交座標系（ｘ，ｙ，ｚ）の各座標軸に平行な楕円面を定め、繰り返し取得した測定データを直交座標系（ｘ，ｙ，ｚ）上に配置し、配置した各測定点と楕円面との距離が最小となるように、感度補正係数αｘ，αｙ，αｚおよび楕円面の中心座標であるオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚを統計的手法によって算出するようになっている。
【０１３８】
これにより、携帯機器２０１の向きを任意の方向に変化させるだけで３軸磁気センサ１１の感度またはオフセットを補正することができるので、従来に比して、３軸磁気センサ１１の感度を比較的簡単かつ正確に補正することができるとともに、３軸磁気センサ１１のオフセットを比較的簡単に補正することができる。また、不揮発性メモリを携帯機器２０１に内蔵する必要もなく、製造時に３軸磁気センサ１１の選別を行う必要もないので、従来に比して、携帯機器２０１の製造コストを低減することができる。
【０１３９】
さらに、本実施の形態では、共役勾配法により上式（３８）のＳを最小にして、感度補正係数αｘ，αｙ，αｚおよびオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚを算出するようになっている。
これにより、測定データに誤差が含まれていても、感度補正係数αｘ，αｙ，αｚおよびオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚを比較的正確に算出することができる。したがって、３軸磁気センサ１１の感度またはオフセットをさらに正確に補正することができる。
【０１４０】
上記第１の実施の形態において、３軸磁気センサ１１は、請求項１若しくは２記載の検出手段、または請求項５、１２若しくは２１記載の地磁気検出手段に対応し、補正計算部１６は、請求項１、２、５、１２または２１記載の出力補正手段に対応し、オフセット・感度補正係数算出部１８は、請求項１、２、５、７若しくは２１記載の検出出力取得手段、または請求項１、２、５、７、８、１２若しくは２１記載の楕円面解析手段に対応している。また、測定データは、請求項１、２、５、７、２１または２３記載の３軸出力データ群に対応し、共役勾配法は、請求項８記載の多次元最適化手法に対応している。
【０１４１】
次に、本発明の第２の実施の形態を説明する。なお、以下、上記第１の実施の形態と異なる部分についてのみ説明し、上記第１の実施の形態と重複する部分については同一の符号を付して説明を省略する。
本実施の形態は、本発明に係る計測装置、方位角計測装置およびキャリブレーションプログラム、並びにキャリブレーション方法を、図２に示すように、携帯機器２０１の３軸磁気センサ１１の感度およびオフセットを補正する場合について適用したものであり、上記第１の実施の形態と異なるのは、上式（３８）のＳを最小にする方法として他の算出方法を採用した点にある。
【０１４２】
上式（３８）のＳが最小となるように、感度補正係数αｘ，αｙ，αｚおよびオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚを算出する方法を説明する。
上式（３９）〜（４１）は、上式（３８）のＳが最小となるとき、下式（４５）〜（４７）に示すように右辺がゼロとなる。
【０１４３】
【数４１】

【０１４４】
【数４２】

【０１４５】
【数４３】

【０１４６】
上式（４５）〜（４７）を行列で表現すると、下式（４８）に示すようになり、αｘ^２，αｙ^２，αｚ^２に関する連立一次方程式になっていることがわかる。
【０１４７】
【数４４】

【０１４８】
したがって、次のステップ（１）〜（４）の手順で、感度補正係数αｘ，αｙ，αｚおよびオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚを算出することができる。
（１）感度補正係数αｘ，αｙ，αｚに適当な初期値を設定する。
（２）オフセットＣｒｘ，Ｃｒｙ，Ｃｒｚを独立変数として、多次元最適化手法を用いて上式（３８）のＳを最小にする。多次元最適化手法として、共役勾配法を用いる場合、Ｓの導関数として上式（４２）〜（４４）を計算すればよい。
（３）上式（４８）を解いてαｘ^２，αｙ^２，αｚ^２を算出する。
（４）感度補正係数αｘ，αｙ，αｚが収束しているか否かを判定し、収束していないと判定したときは、ステップ（２），（３）を繰り返し行う。
【０１４９】
このようにして、本実施の形態では、感度補正係数αｘ，αｙ，αｚに初期値を設定するステップ（１）と、多次元最適化手法により上式（３８）を解いてオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚを算出するステップ（２）と、連立一次方程式である上式（４８）を解いて感度補正係数αｘ，αｙ，αｚを算出するステップ（３）と、ステップ（３）で算出した感度補正係数αｘ，αｙ，αｚが収束するまでステップ（２），（３）を繰り返し行うステップ（４）とを含む。
【０１５０】
これにより、多次元最適化手法により感度補正係数αｘ，αｙ，αｚだけを算出するので、上記第１の実施の形態における算出方法に比して、収束解を早く得ることができる。したがって、感度補正係数αｘ，αｙ，αｚおよびオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚを比較的高速に算出することができる。
【０１５１】
上記第２の実施の形態において、３軸磁気センサ１１は、請求項１若しくは２記載の検出手段、または請求項５、１２若しくは２１記載の地磁気検出手段に対応し、補正計算部１６は、請求項１、２、５、１２または２１記載の出力補正手段に対応し、オフセット・感度補正係数算出部１８は、請求項１、２、５、７若しくは２１記載の検出出力取得手段、または請求項１、２、５、７、９、１２若しくは２１記載の楕円面解析手段に対応している。また、測定データは、請求項１、２、５、７、２１または２３記載の３軸出力データ群に対応し、共役勾配法は、請求項９記載の多次元最適化手法に対応し、ステップ（２）は、請求項９記載の第１解析処理に対応し、ステップ（３）は、請求項９記載の第２解析処理に対応している。
【０１５２】
また、上記第２の実施の形態において、ステップ（４）は、請求項９記載の第３解析処理に対応している。
次に、本発明の第３の実施の形態を説明する。なお、以下、上記第１の実施の形態と異なる部分についてのみ説明し、上記第１の実施の形態と重複する部分については同一の符号を付して説明を省略する。
【０１５３】
本実施の形態は、本発明に係る計測装置、方位角計測装置およびキャリブレーションプログラム、並びにキャリブレーション方法を、図２に示すように、携帯機器２０１の３軸磁気センサ１１の感度およびオフセットを補正する場合について適用したものであり、上記第１の実施の形態と異なるのは、上式（３８）のＳを最小にする方法として他の算出方法を採用した点にある。
【０１５４】
上式（３８）のＳが最小となるように、感度補正係数αｘ，αｙ，αｚおよびオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚを算出する方法を説明する。
上式（３７）をオフセットＣｘ，Ｃｙ，Ｃｚ，ａ０Ｍで偏微分すると、下式（４９）〜（５２）が得られる。
【０１５５】
【数４５】

【０１５６】
【数４６】

【０１５７】
【数４７】

【０１５８】
【数４８】

【０１５９】
上式（４９）〜（５２）は、上式（３７）のＳが最小となるとき、右辺がゼロとなる。したがって、下式（５３）〜（５６）が得られる。
【０１６０】
【数４９】

【０１６１】
【数５０】

【０１６２】
【数５１】

【０１６３】
【数５２】

【０１６４】
上式（５６）を上式（５３）〜（５５）に代入すると、下式（５７）〜（５９）が得られ、オフセットＣｘ，Ｃｙ，Ｃｚに関する連立一次方程式が導出される。
【０１６５】
【数５３】

【０１６６】
【数５４】

【０１６７】
【数５５】

【０１６８】
ただし、上式（５７）〜（５９）の各値は、下式（６０）〜（７７）により得られる。
【０１６９】
【数５６】

【０１７０】
【数５７】

【０１７１】
【数５８】

【０１７２】
【数５９】

【０１７３】
【数６０】

【０１７４】
【数６１】

【０１７５】
【数６２】

【０１７６】
【数６３】

【０１７７】
【数６４】

【０１７８】
【数６５】

【０１７９】
【数６６】

【０１８０】
【数６７】

【０１８１】
【数６８】

【０１８２】
【数６９】

【０１８３】
【数７０】

【０１８４】
【数７１】

【０１８５】
【数７２】

【０１８６】
【数７３】

【０１８７】
したがって、次のステップ（１）〜（４）の手順で、感度補正係数αｘ，αｙ，αｚおよびオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚを算出することができる。
（１）感度補正係数αｘ，αｙ，αｚに適当な初期値を設定する。
（２）上式（２６）〜（２８）により、Ｓ１ｒｘ，Ｓ２ｒｘ，…，ＳＮｒｘ，Ｓ１ｒｙ，Ｓ２ｒｙ，…，ＳＮｒｙ，Ｓ１ｒｚ，Ｓ２ｒｚ，…，ＳＮｒｚから、Ｓ１ｘ，Ｓ２ｘ，…，ＳＮｘ，Ｓ１ｙ，Ｓ２ｙ，…，ＳＮｙ，Ｓ１ｚ，Ｓ２ｚ，…，ＳＮｚを算出する。
（３）上式（５７）〜（５９）を解いてオフセットＣｘ，Ｃｙ，Ｃｚを算出する。
（４）上式（１２）〜（１４）により、オフセットＣｘ，Ｃｙ，Ｃｚから、オフセットＣｒｘ，Ｃｒｙ，Ｃｒｚを算出する。
（５）上式（４８）を解いてαｘ^２，αｙ^２，αｚ^２を算出する。
（６）感度補正係数αｘ，αｙ，αｚが収束しているか否かを判定し、収束していないと判定したときは、ステップ（２）〜（５）を繰り返し行う。
【０１８８】
このようにして、本実施の形態では、上式（５７）〜（５９）によりオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚを算出するステップ（１）〜（４）と、ステップ（１）〜（４）で算出した値に基づいて上式（４８）により感度補正係数αｘ，αｙ，αｚを算出するステップ（５）と、ステップ（１）〜（４）で算出した値が収束するまでステップ（２）〜（５）を繰り返し行うステップ（６）とを含む。
【０１８９】
これにより、上記第２の実施の形態における算出方法に比して、収束解を早く得ることができる。したがって、感度補正係数αｘ，αｙ，αｚおよびオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚを比較的高速に算出することができる。
上記第３の実施の形態において、３軸磁気センサ１１は、請求項１若しくは２記載の検出手段、または請求項５、１２若しくは２１記載の地磁気検出手段に対応し、補正計算部１６は、請求項１、２、５、１２または２１記載の出力補正手段に対応し、オフセット・感度補正係数算出部１８は、請求項１、２、５、７若しくは２１記載の検出出力取得手段、または請求項１、２、５、７、１０、１２若しくは２１記載の楕円面解析手段に対応している。また、測定データは、請求項１、２、５、７、２１または２３記載の３軸出力データ群に対応し、ステップ（１）〜（４）は、請求項１０記載の第１解析処理に対応し、ステップ（５）は、請求項１０記載の第２解析処理に対応し、ステップ（６）は、請求項１０記載の第３解析処理に対応している。
【０１９０】
なお、上記第１ないし第３の実施の形態においては、方位角計測装置が携帯機器２０１に組み込まれていることを前提に説明したが、ＰＤＡ（Ｐｅｒｓｏｎａｌ Ｄｉｇｉｔａｌ Ａｓｓｉｓｔａｎｔ）やノートパソコンなどの携帯機器２０１に対して抜き差し（脱着）可能な容器に方位角計測装置を収容し、この方位角計測装置を携帯機器２０１に装着して使用するようにしてもよい。
【０１９１】
例えば、ノートパソコンに標準装備されているＰＣカードスロットに挿入されるＰＣＭＣＩＡカードの中に、方位角計測装置とそのデータ処理ＩＣ、インターフェースＩＣなどを設け、そのドライバとして、上述したキャリブレーション機能を組み込むようにしてもよい。
ＰＣカードスロットは、機械的および電気的な特性に対する規格はあるが、スロット内部の漏洩磁束密度等の磁気的な特性に対する規格は無いため、汎用のＰＣＭＣＩＡカードの中に設けた方位角計測装置は、ノートパソコンから発生する漏洩磁束密度をあらかじめ予測することができない。
【０１９２】
ここで、ＰＣＭＣＩＡカードの中に方位角計測装置のキャリブレーション機能を組み込むことにより、ＰＣカードスロットの漏洩磁場が携帯機器２０１ごとにばらつく場合においても、方位角計測装置のオフセットを精度よく補正することができ、特定の携帯機器２０１に限られることなく、方位角計測装置を自由に装着して使用することが可能となる。
【０１９３】
なお、ＰＣＭＣＩＡカードには、方位角計測装置以外にも、傾斜角センサや、ＧＰＳ（Ｇｌｏｂａｌ Ｐｏｓｉｔｉｏｎｉｎｇ Ｓｙｓｔｅｍ）の信号処理ＩＣ、アンテナなどを一緒に搭載するようにしてもよいし、カード形式も、ＰＣＭＣＩＡカードに限られることなく、ＣＦカードスロットに対応させるようにしてもよい。
また、上記第１ないし第３の実施の形態においては、磁気センサとしてホール素子を用いた場合を例にとって説明したが、磁気センサが必ずしもホール素子に限定されることなく、例えば、ブラックスゲートセンサなどを用いるようにしてもよい。
【０１９４】
また、上記第１ないし第３の実施の形態において、オフセット・感度補正係数算出部１８は、直交座標系（ｘ，ｙ，ｚ）上に、各主軸が直交座標系（ｘ，ｙ，ｚ）の各座標軸に平行な楕円面を定め、繰り返し取得した測定データに基づいて、感度補正係数αｘ，αｙ，αｚおよびオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚを算出するように構成したが、これに限らず、出力増幅値Ｓｘ、Ｓｙ、Ｓｚのうち変化の度合いが最小のものについてその変化の度合いが所定値以下であるときは、変化の度合いが所定値以下の出力増幅値に対応する座標軸を特定軸とし、直交座標系（ｘ，ｙ，ｚ）から特定軸を除いた２次元直交座標系上に、各軸が２次元直交座標系の各座標軸に平行な楕円を定め、出力増幅値Ｓｘ、Ｓｙ、Ｓｚのうち特定軸に対応するもの以外のものに基づいて、感度補正係数αｘ，αｙ，αｚおよびオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚのうち特定軸に対応するもの以外のものを算出するように構成することもできる。
【０１９５】
これにより、３軸磁気センサ１１の３軸のうちいずれかの軸に垂直な面上でのみ方位角計測装置を移動・回転等させた場合であっても、感度補正係数αｘ，αｙ，αｚおよびオフセットＣｒｘ，Ｃｒｙ，Ｃｒｚのうち方位角計測装置を移動・回転等させた面に平行な２軸に対応するものについて比較的正確に算出することができる。
【０１９６】
この場合において、オフセット・感度補正係数算出部１８は、請求項１１記載の検出出力取得手段、または請求項１１記載の楕円面解析手段に対応し、測定データは、請求項１１記載の３軸出力データ群に対応している。
また、上記第１ないし第３の実施の形態においては、オフセット・感度補正係数算出部１８で行う処理をハードウェアにより実現する場合について説明したが、これに限らず、携帯機器２０１を、ＣＰＵ、ＲＯＭおよびＲＡＭをバス接続したコンピュータとして構成し、ＣＰＵがこれらの処理を実行するようにしてもよい。この場合、ＲＯＭにあらかじめ格納されている制御プログラムを実行するように構成してもよいが、これらの手順を示したプログラムが記憶された記憶媒体から、そのプログラムをＲＡＭに読み込んで実行するようにしてもよい。
【０１９７】
ここで、記憶媒体とは、ＲＡＭ、ＲＯＭ等の半導体記憶媒体、ＦＤ、ＨＤ等の磁気記憶型記憶媒体、ＣＤ、ＣＤＶ、ＬＤ、ＤＶＤ等の光学的読取方式記憶媒体、ＭＯ等の磁気記憶型／光学的読取方式記憶媒体であって、電子的、磁気的、光学的等の読み取り方法のいかんにかかわらず、コンピュータで読み取り可能な記憶媒体であれば、あらゆる記憶媒体を含むものである。
【０１９８】
また、上記第１ないし第３の実施の形態においては、本発明に係る計測装置、方位角計測装置およびキャリブレーションプログラム、並びにキャリブレーション方法を、図２に示すように、携帯機器２０１の３軸磁気センサ１１の感度およびオフセットを補正する場合について適用したが、これに限らず、本発明の主旨を逸脱しない範囲で他の場合にも適用可能である。
【０１９９】
【発明の効果】
以上説明したように、本発明に係る請求項１または３記載の計測装置によれば、計測装置の向きを任意の方向に変化させるだけで検出手段の感度を補正することができるので、従来に比して、検出手段の感度を比較的簡単かつ正確に補正することができるという効果が得られる。また、不揮発性メモリを内蔵する必要もなく、製造時に検出手段の選別を行う必要もないので、従来に比して、計測装置の製造コストを低減することができるという効果も得られる。
【０２００】
さらに、本発明に係る請求項２または４記載の計測装置によれば、計測装置の向きを任意の方向に変化させるだけで検出手段のオフセットを補正することができるので、従来に比して、検出手段のオフセットを比較的簡単に補正することができるという効果が得られる。
一方、本発明に係る請求項５ないし２０記載の方位角計測装置によれば、方位角計測装置の向きを任意の方向に変化させるだけで地磁気検出手段の感度またはオフセットを補正することができるので、従来に比して、地磁気検出手段の感度を比較的簡単かつ正確に補正することができるとともに、地磁気検出手段のオフセットを比較的簡単に補正することができるという効果が得られる。また、不揮発性メモリを内蔵する必要もなく、製造時に地磁気検出手段の選別を行う必要もないので、従来に比して、方位角計測装置の製造コストを低減することができるという効果も得られる。
【０２０１】
さらに、本発明に係る請求項７ないし１０記載の方位角計測装置によれば、各測定点と楕円面との距離が最小となるように、楕円面の各主軸の長さおよび中心座標を統計的手法によって算出するので、３軸出力データに測定誤差が含まれていても、楕円面の各主軸の長さおよび中心座標を比較的正確に算出することができる。したがって、地磁気検出手段の感度またはオフセットをさらに正確に補正することができるという効果も得られる。
【０２０２】
さらに、本発明に係る請求項８記載の方位角計測装置によれば、多次元最適化手法により誤差総和演算式を解いて楕円面の各主軸の長さおよび中心座標を算出するので、楕円面の各主軸の長さおよび中心座標をさらに正確に算出することができる。したがって、地磁気検出手段の感度またはオフセットをさらに正確に補正することができるという効果も得られる。
【０２０３】
さらに、本発明に係る請求項９記載の方位角計測装置によれば、楕円面の各主軸の長さを多次元最適化手法によらずに連立一次方程式を解くことにより算出するので、請求項８記載の方位角計測装置に比して、収束解を早く得ることができる。したがって、楕円面の各主軸の長さおよび中心座標を比較的高速に算出することができるという効果も得られる。
【０２０４】
さらに、本発明に係る請求項１０記載の方位角計測装置によれば、多次元最適手法によらず第１解析処理と第２解析処理との反復計算により楕円面の各主軸の長さおよび中心座標を算出するので、請求項９記載の方位角計測装置に比して、収束解を早く得ることができる。したがって、楕円面の各主軸の長さおよび中心座標を比較的高速に算出することができるという効果も得られる。
【０２０５】
さらに、本発明に係る請求項１１記載の方位角計測装置によれば、地磁気検出手段の３軸のうちいずれかの軸に垂直な面上でのみ方位角計測装置を移動・回転等させた場合であっても、残りの２軸について地磁気検出手段の感度またはオフセットを補正することができるという効果も得られる。
さらに、本発明に係る請求項１３記載の方位角計測装置によれば、方位角計測装置の向きが静止していたり、僅かしか変化していなかった場合に、楕円面の各主軸の長さおよび中心座標が大きな誤差を含んで算出されることを防止することができ、楕円面の各主軸の長さおよび中心座標の算出精度を向上させて、感度およびオフセットのキャリブレーション精度を高く保つことができるという効果も得られる。
【０２０６】
さらに、本発明に係る請求項１４記載の方位角計測装置によれば、地磁気の検出出力にノイズ等で大きな誤差が含まれている場合や、特に２軸の地磁気検出手段の向きが所定の平面から外れて変化したような場合に、誤った感度若しくはオフセット値を算出して不適切な出力補正が行われてしまうことを防止することができるという効果も得られる。
【０２０７】
さらに、本発明に係る請求項１５記載の方位角計測装置によれば、利用者が方位角計測を行うことで、各軸出力の補正を自動的に行うことが可能となるという効果も得られる。
さらに、本発明に係る請求項１６または１７記載の方位角計測装置によれば、ユーザは良好性情報を参照すれば、出力補正手段による補正の良好性を把握することができるという効果も得られる。
【０２０８】
さらに、本発明に係る請求項１７記載の方位角計測装置によれば、区分ごとに対応した良好度（例えば、優、良、可のような良好度）を得ることができるので、出力補正手段による補正の良好性がさらに把握しやすくなるという効果も得られる。
さらに、本発明に係る請求項１８記載の方位角計測装置によれば、静的な外部環境磁場が存在している場合や、地磁気がシールドされているような場合に、地磁気が正しく検出されていないにもかかわらず方位角計測が行われてしまうことを防止することができるという効果も得られる。
【０２０９】
さらに、本発明に係る請求項１９または２０記載の方位角計測装置によれば、ユーザは信頼性情報を参照すれば、方位角計測結果の信頼性を把握することができるという効果も得られる。
さらに、本発明に係る請求項２０記載の方位角計測装置によれば、区分ごとに対応した信頼度（例えば、優、良、可のような信頼度）を得ることができるので、方位角計測結果の信頼性がさらに把握しやすくなるという効果も得られる。
【０２１０】
一方、本発明に係る請求項２１記載のキャリブレーションプログラムによれば、請求項５記載の方位角計測装置と同等の効果が得られる。
さらに、本発明に係る請求項２２記載のキャリブレーションプログラムによれば、請求項６記載の方位角計測装置と同等の効果が得られる。
一方、本発明に係る請求項２３記載のキャリブレーション方法によれば、請求項５記載の方位角計測装置と同等の効果が得られる。
さらに、本発明に係る請求項２４記載のキャリブレーション方法によれば、請求項６記載の方位角計測装置と同等の効果が得られる。
【図面の簡単な説明】
【図１】本発明を適用する携帯機器２０１の概観構成を透視して示す斜視図である。
【図２】本発明に係る方位角計測装置の概略構成を示すブロック図である。
【図３】キャリブレーション方法の概念を説明する図である。
【図４】方位角計測装置をｚ軸回りに一定の角速度で回転させた時の磁気センサの出力波形を示す図である。
【図５】従来の方位角計測装置のキャリブレーション方法を示すフローチャートである。
【符号の説明】
２０１ 携帯機器
２０２ 表示部
２０３ アンテナ
１１ ３軸磁気センサ
ＨＥｘ ｘ軸ホール素子
ＨＥｙ ｙ軸ホール素子
ＨＥｚ ｚ軸ホール素子
１２ 磁気センサ駆動電源部
１３ チョッパ部
１４ 差動入力アンプ
１５ Ａ／Ｄ変換部
１６ 補正計算部
１７ 方位角計算部
１８ オフセット・感度補正係数算出部
１９ａ オフセット情報記憶部
１９ｂ 感度補正情報記憶部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a measurement device, an azimuth measurement device, a calibration program, and a calibration method for correcting the sensitivity and offset of a magnetic sensor, and in particular, to reduce costs and easily and accurately correct the sensitivity of a magnetic sensor. The present invention relates to a measurement device, an azimuth measurement device, a calibration program, and a calibration method capable of easily correcting an offset of a magnetic sensor.
[0002]
[Prior art]
In the azimuth angle measuring device, (1) the sensitivity of the magnetic sensor varies from product to product, and (2) the sensitivity of the magnetic sensor has temperature characteristics, and furthermore, the temperature characteristics vary from product to product. In order to perform an accurate measurement, it is necessary to correct the sensitivity of the magnetic sensor prior to the measurement.
[0003]
Conventionally, the following three methods have been employed to correct the sensitivity of a magnetic sensor.
The first correction method selects and uses magnetic sensors having the same or almost the same sensitivity and temperature characteristics during manufacturing.
The second correction method measures correction data for correcting the sensitivity of the magnetic sensor in a predetermined temperature and magnetic field at the time of manufacturing, stores the measured correction data in a nonvolatile memory, and sends the corrected data to an azimuth measuring device. It is built-in and corrects the sensitivity of the magnetic sensor at the time of measurement based on the correction data in the nonvolatile memory.
[0004]
The third correction method uses a correction value calculation method of an electronic compass as disclosed in Patent Document 1, measures correction data as needed when the environment changes, etc. The data is stored in a memory, and the sensitivity of the magnetic sensor is corrected based on the correction data in the nonvolatile memory at the time of measurement.
On the other hand, when a magnetized component such as a speaker is arranged around the magnetic sensor, an offset occurs in the output of the magnetic sensor due to a magnetic field leaking from the magnetized component.
[0005]
Therefore, in an azimuth angle measuring device that detects an azimuth using a magnetic sensor, the azimuth angle is intended to correct the offset of the magnetic sensor in order to prevent an error in the calculation of the azimuth angle due to the offset of the magnetic sensor. It is necessary to calibrate the measuring device.
For this reason, in the conventional azimuth measuring device, for example, the azimuth measuring device is calibrated by rotating the azimuth measuring device around a specific axis at a constant angular velocity.
[0006]
FIG. 4 is a diagram illustrating an output waveform of the magnetic sensor when the azimuth measuring device is rotated around the z-axis at a constant angular velocity.
In FIG. 4, when the portable device 301 is rotated around the z-axis at a constant angular velocity ω, the output Srx of the x-axis Hall element HEx mounted on the portable device 301 is given by the following equation (1).
[0007]
Srx = a_XM_XYcos (ωt + θ₀) + X₀                  … (1)
Where a_XIs the sensitivity of the x-axis Hall element HEx, X₀Is the offset of the x-axis Hall element HEx.
Also,
M_XY= √ (M_X ²+ M_Y ²)
θ₀= Tan^-1(M_Y/ M_X)
It is. Where M_XIs the x-direction component of the geomagnetism M, M_YIs the y-direction component of the geomagnetism M.
[0008]
Therefore, the maximum value X of the output Srx of the x-axis Hall element HEx_maxAnd the minimum value X_minCan be represented by the following equations (2) and (3).
X_max= A_XM_XY+ X₀                                        … (2)
X_min= -A_XM_XY+ X₀                                      … (3)
As a result, from the above equations (2) and (3), the offset X of the x-axis Hall element HEx is obtained.₀Can be obtained by the following equation (4).
[0009]
X₀= (X_max+ X_min) / 2… (4)
FIG. 5 is a flowchart showing a calibration method of the conventional azimuth measuring device.
In FIG. 5, a calibration start button of the mobile device 301 is pressed (step S21).
[0010]
Then, the portable device 301 on which the x-axis Hall element HEx is mounted is horizontally rotated at a constant speed slowly while keeping the portable device 301 horizontal (step S22).
Then, when the portable device 301 is rotated once, the calibration end button of the portable device 301 is pressed (step S23).
Here, during one rotation of the portable device 301, the maximum value X of the output Srx of the x-axis Hall element HEx_maxAnd the minimum value X_minAnd add these values and divide by 2 to get the x-axis offset X₀By doing so, x-axis calibration can be performed.
[0011]
[Patent Document 1]
JP 2000-13068 A
[0012]
[Problems to be solved by the invention]
However, in the first conventional correction method, it is not practical in terms of cost to use magnetic sensors having the same or almost the same sensitivity and temperature characteristics.
In addition, in the above-mentioned second conventional correction method, a temperature-controlled constant temperature bath and a device for generating a constant magnetic field are required, and the azimuth angle measurement device is required to store correction data. Since a non-volatile memory needs to be provided, there is a problem that the cost is increased.
[0013]
In the above third conventional correction method, the correction data of the magnetic sensor is measured while keeping the azimuth angle measuring device horizontal and in three directions orthogonal to each other. When the azimuth angle measuring device is portable, it is troublesome for the user to carry out such an operation by holding it in his hand, and if the azimuth cannot be kept horizontal during the measurement or the direction is not exactly orthogonal, the azimuth measurement device may be used. An error may occur in the angle calculation. Further, since the geomagnetism is on the order of 0.01 [mT] and extremely weak, the S / N ratio of the magnetic sensor output data is not good. Therefore, there is a problem that accurate correction cannot be performed in at most three measurements.
[0014]
On the other hand, in the above conventional azimuth angle measuring device for correcting the offset, the maximum value Xr of the output Srx of the x-axis Hall element HEx is obtained._maxAnd the minimum value X_min, It is necessary to rotate the portable device 301 one or more rounds on a specific plane.
As a result, if the rotation speed of the portable device 301 is too fast, the maximum value X_maxAnd the minimum value X_minOn the other hand, if the rotation speed is too slow, the number of read data is enormous, and the accuracy of the calibration is degraded when the speed is out of a certain speed range such as overflow of the memory.
[0015]
Therefore, the user is required to repeat the trial and error until the calibration is successful, and to rotate the portable device 301 many times.
Therefore, the present invention has been made in view of the unsolved problems of the conventional technology, and can reduce the cost, easily and accurately correct the sensitivity of the magnetic sensor, It is an object of the present invention to provide a measuring device, an azimuth measuring device, a calibration program, and a calibration method that can easily correct an offset of a magnetic sensor.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, a measuring device according to claim 1 of the present invention comprises: three or more axes detecting means for detecting a vector physical quantity; and three axes when the direction of the detecting means changes in a three-dimensional space. Detecting output obtaining means for obtaining an output repeatedly a predetermined number of times or more, and an elliptical surface in which each main axis is parallel to each coordinate axis of the three-dimensional coordinates on a three-dimensional coordinate having the three-axis output as a component; An ellipsoidal analysis means for calculating the length of each principal axis of the ellipsoid based on the three-axis output data group repeatedly acquired by the acquisition means, and a length of each principal axis of the ellipse calculated by the ellipsoidal analysis means. Output correction means for correcting the three-axis output of the detection means based on the output signal.
[0017]
With such a configuration, when the direction is changed to an arbitrary direction by moving / rotating the measuring device in the three-dimensional space, the direction of the detecting unit is changed in the three-dimensional space by the detection output obtaining unit. The three-axis output at the time is repeatedly acquired a predetermined number of times or more. Next, the ellipsoid analysis unit determines an ellipsoid whose main axis is parallel to each coordinate axis of the three-dimensional coordinates on the three-dimensional coordinates having the three-axis output as a component, based on the repeatedly obtained three-axis output data group. , The length of each principal axis of the ellipsoid is calculated. Then, the output correction means corrects the three-axis output of the detection means based on the calculated lengths of the main axes of the elliptical surface.
[0018]
This makes it possible to correct the output of each axis of the detection means only by changing the direction of the measuring device to an arbitrary direction. Here, in order to correct the output of each axis of the detection means, there is no limitation on the range in which the direction at the time of detecting the three-axis output data group changes. Alternatively, the position of the measuring device may change when the three-axis output data group is detected. Therefore, when correcting the sensitivity of the detection means, it is possible to realize the correction of the sensitivity only by changing the measured value of the vector physical quantity at the time of movement of the measuring device or during normal operation without any user's awareness. Therefore, the sensitivity of the detecting means can be corrected relatively easily and accurately as compared with the related art.
[0019]
Further, since it is not necessary to store the correction data, it is not necessary to incorporate a nonvolatile memory. Further, since the correction is performed at the time of measurement, it is not necessary to select the detection means at the time of manufacturing. Therefore, the manufacturing cost of the measuring device can be reduced as compared with the related art.
Further, the measuring device according to claim 2 of the present invention repeats three-axis or more detecting means for detecting a vector physical quantity and three-axis output when the direction of the detecting means changes in a three-dimensional space a predetermined number of times or more. And an elliptical surface in which each main axis is parallel to each coordinate axis of the three-dimensional coordinates is determined on the three-dimensional coordinate having the three-axis output as a component, and the elliptic surface is repeatedly acquired by the detection output obtaining means. Elliptical surface analysis means for calculating the center coordinates of the ellipsoid based on the three-axis output data group, and output correction for correcting the three-axis output of the detection means based on the center coordinates calculated by the ellipsoid analysis means Means.
[0020]
With such a configuration, when the direction is changed to an arbitrary direction by moving / rotating the measuring device in the three-dimensional space, the direction of the detecting unit is changed in the three-dimensional space by the detection output obtaining unit. The three-axis output at the time is repeatedly acquired a predetermined number of times or more. Next, the ellipsoid analysis unit determines an ellipsoid whose main axis is parallel to each coordinate axis of the three-dimensional coordinates on the three-dimensional coordinates having the three-axis output as a component, based on the repeatedly obtained three-axis output data group. , The center coordinates of the ellipsoid are calculated. Then, the output correction unit corrects the three-axis output of the detection unit based on the calculated center coordinates.
[0021]
This makes it possible to correct the output of each axis of the detection means only by changing the direction of the measuring device to an arbitrary direction. Here, in order to correct the output of each axis of the detection means, there is no limitation on the range in which the direction at the time of detecting the three-axis output data group changes. Alternatively, the position of the measuring device may change when the three-axis output data group is detected. Therefore, when correcting the offset of the detecting means, the correction of the offset can be realized only by changing the measured value of the vector physical quantity at the time of movement or normal operation of the measuring device without any user awareness. Therefore, the offset of the detecting means can be corrected relatively easily as compared with the related art.
[0022]
Further, the measuring device according to claim 3 according to the present invention, further comprising: two-axis or more detecting means for detecting a vector physical quantity; and a two-axis output when the direction of the detecting means changes while being kept on a predetermined plane. And a detection output obtaining means for repeatedly obtaining a predetermined number of times or more, and an ellipse whose main axis is parallel to each coordinate axis of the two-dimensional coordinates on two-dimensional coordinates having the two-axis output as a component. An ellipse analyzing means for calculating the length of each principal axis of the ellipse based on the two-axis output data group repeatedly obtained in the step, and the detecting means based on a length of each principal axis of the ellipse calculated by the ellipse analyzing means. Output correction means for correcting the two-axis output of the above.
[0023]
With such a configuration, if the direction of the measuring device is changed to an arbitrary direction by moving, rotating, or the like while maintaining the measurement device on a predetermined plane, the direction of the detecting device is determined by the detection output obtaining device. The biaxial output when changed while being kept on the plane is repeatedly obtained a predetermined number of times or more. Next, an ellipse whose main axis is parallel to each coordinate axis of the two-dimensional coordinates is determined on the two-dimensional coordinates having a component of the two-axis output by the ellipse analysis means, and the ellipse is determined based on the repeatedly obtained two-axis output data group. Are calculated. Then, the output correction unit corrects the biaxial output of the detection unit based on the calculated lengths of the main axes of the ellipse.
[0024]
Thus, it is possible to correct the output of each axis of the detecting means only by changing the direction of the measuring device to an arbitrary direction while keeping the direction of the measuring device on a predetermined plane. Here, in order to correct each axis output of the detection means, there is no limitation on the range in which the direction changes at the time of detecting the two-axis output data group. For example, it may be less than 180 degrees or less than 90 degrees. Alternatively, the position of the measurement device may change when the two-axis output data group is detected. Therefore, when correcting the sensitivity of the detection means, it is possible to realize the correction of the sensitivity only by changing the measured value of the vector physical quantity at the time of movement of the measuring device or during normal operation without any user's awareness. Therefore, the sensitivity of the detecting means can be corrected relatively easily and accurately as compared with the related art.
[0025]
Further, since it is not necessary to store the correction data, it is not necessary to incorporate a nonvolatile memory. Further, since the correction is performed at the time of measurement, it is not necessary to select the detection means at the time of manufacturing. Therefore, the manufacturing cost of the measuring device can be reduced as compared with the related art.
Further, the measuring device according to claim 4 according to the present invention, further comprising: two-axis or more detecting means for detecting a vector physical quantity; and a two-axis output when the direction of the detecting means changes while being kept on a predetermined plane. And a detection output obtaining means for repeatedly obtaining a predetermined number of times or more, and an ellipse whose main axis is parallel to each coordinate axis of the two-dimensional coordinates on two-dimensional coordinates having the two-axis output as a component. An ellipse analyzing means for calculating the center coordinates of the ellipse based on the two-axis output data group repeatedly obtained in the step, and an output for correcting the two-axis outputs of the detecting means based on the center coordinates calculated by the ellipse analyzing means. Correction means.
[0026]
With such a configuration, if the direction of the measuring device is changed to an arbitrary direction by moving, rotating, or the like while maintaining the measurement device on a predetermined plane, the direction of the detecting device is determined by the detection output obtaining device. The biaxial output when changed while being kept on the plane is repeatedly obtained a predetermined number of times or more. Next, an ellipse whose main axis is parallel to each coordinate axis of the two-dimensional coordinates is determined on the two-dimensional coordinates having a component of the two-axis output by the ellipse analysis means, and the ellipse is determined based on the repeatedly obtained two-axis output data group. Are calculated. Then, the two-axis output of the detection unit is corrected by the output correction unit based on the calculated center coordinates.
[0027]
Thus, it is possible to correct the output of each axis of the detecting means only by changing the direction of the measuring device to an arbitrary direction while keeping the direction of the measuring device on a predetermined plane. Here, in order to correct each axis output of the detection means, there is no limitation on the range in which the direction changes at the time of detecting the two-axis output data group. For example, it may be less than 180 degrees or less than 90 degrees. Alternatively, the position of the measurement device may change when the two-axis output data group is detected. Therefore, when correcting the offset of the detecting means, the correction of the offset can be realized only by changing the measured value of the vector physical quantity at the time of movement or normal operation of the measuring device without any user awareness. Therefore, the offset of the detecting means can be corrected relatively easily as compared with the related art.
[0028]
On the other hand, in order to achieve the above object, an azimuth angle measuring apparatus according to claim 5 of the present invention comprises: three or more axes of geomagnetism detecting means for detecting geomagnetism; and the direction of the geomagnetism detecting means changes in three-dimensional space. Detection output acquiring means for repeatedly acquiring the three-axis output at the time of performing the predetermined number of times or more, and an elliptical surface in which each main axis is parallel to each coordinate axis of the three-dimensional coordinates on three-dimensional coordinates having the three-axis output as a component. An ellipsoidal surface analyzing means for calculating the length and center coordinates of each principal axis of the ellipsoidal surface based on the three-axis output data group repeatedly obtained by the detection output obtaining means, and an ellipse calculated by the elliptical surface analyzing means. Output correction means for correcting the three-axis output of the geomagnetic detection means based on the length and center coordinates of each principal axis of the surface.
[0029]
With such a configuration, when the direction is changed to an arbitrary direction by moving / rotating the azimuth angle measuring device in the three-dimensional space, the direction of the geomagnetism detecting unit is changed by the detection output acquiring unit to the three-dimensional space. The three-axis output at the time of the change is repeatedly obtained a predetermined number of times or more. Next, the ellipsoid analysis unit determines an ellipsoid whose main axis is parallel to each coordinate axis of the three-dimensional coordinates on the three-dimensional coordinates having the three-axis output as a component, based on the repeatedly obtained three-axis output data group. , The length and the center coordinates of each principal axis of the ellipsoid are calculated. Then, the three-axis output of the geomagnetism detecting unit is corrected by the output correcting unit based on the calculated length and center coordinates of each principal axis of the elliptical surface.
[0030]
Thus, each axis output of the geomagnetism detecting means can be corrected only by changing the direction of the azimuth angle measuring device to an arbitrary direction. Here, in order to correct each axis output of the terrestrial magnetism detection means, there is no limitation on the range in which the direction changes when the three-axis output data group is detected, and for example, may be less than 180 degrees or less than 90 degrees. Alternatively, the position of the azimuth angle measurement device may change when the three-axis output data group is detected. Therefore, when the sensitivity or offset of the terrestrial magnetism detecting means is corrected, the user is not conscious of the azimuth angle measuring device when the azimuth angle measuring device is moved or in normal operation, but only when the measured value of terrestrial magnetism changes. Therefore, the sensitivity of the geomagnetism detecting means can be corrected relatively easily and accurately, and the offset of the geomagnetism detecting means can be corrected relatively easily, as compared with the related art. .
[0031]
Further, since it is not necessary to store the correction data, it is not necessary to incorporate a nonvolatile memory. Furthermore, since the correction is performed at the time of measurement, it is not necessary to select the geomagnetic detection means at the time of manufacturing. Therefore, the manufacturing cost of the azimuth angle measuring device can be reduced as compared with the related art.
Further, the azimuth angle measuring device according to claim 6 of the present invention is characterized in that two or more axes of terrestrial magnetism detecting means for detecting terrestrial magnetism and when the orientation of the terrestrial magnetism detecting means changes while being kept on a predetermined plane. Detecting output obtaining means for obtaining a two-axis output repeatedly for a predetermined number of times or more; and determining an ellipse whose main axis is parallel to each coordinate axis of the two-dimensional coordinate on the two-dimensional coordinate having the two-axis output as a component. An ellipse analyzing means for calculating a length and a center coordinate of each principal axis of the ellipse based on the two-axis output data group repeatedly acquired by the output acquiring means, and a length and a principal axis of each ellipse calculated by the ellipse analyzing means; Output correction means for correcting the biaxial output of the geomagnetic detection means based on the center coordinates.
[0032]
With such a configuration, when the direction is changed to an arbitrary direction by moving / rotating the azimuth measuring device while maintaining the azimuth angle measurement device on a predetermined plane, the detection output obtaining unit detects the terrestrial magnetism detecting unit. A biaxial output when the orientation changes while maintaining the orientation on a predetermined plane is repeatedly acquired a predetermined number of times or more. Next, an ellipse whose main axis is parallel to each coordinate axis of the two-dimensional coordinates is determined on the two-dimensional coordinates having a component of the two-axis output by the ellipse analysis means, and the ellipse is determined based on the repeatedly obtained two-axis output data group. The length and center coordinates of each main axis are calculated. Then, the two-axis output of the geomagnetism detecting unit is corrected by the output correcting unit based on the calculated length and center coordinates of each principal axis of the ellipse.
[0033]
Thus, each axis output of the geomagnetism detecting means can be corrected only by changing the direction of the azimuth angle measuring device to an arbitrary direction. Here, in order to correct each axis output of the terrestrial magnetism detection means, there is no limitation on the range in which the direction changes when the two-axis output data group is detected, and for example, may be less than 180 degrees or less than 90 degrees. Alternatively, the position of the azimuth angle measurement device may change when the two-axis output data group is detected. Therefore, when the sensitivity or offset of the terrestrial magnetism detecting means is corrected, the user is not conscious of the azimuth angle measuring device when the azimuth angle measuring device is moved or in normal operation, but only when the measured value of terrestrial magnetism changes. Therefore, the sensitivity of the geomagnetism detecting means can be corrected relatively easily and accurately, and the offset of the geomagnetism detecting means can be corrected relatively easily, as compared with the related art. .
[0034]
Further, since it is not necessary to store the correction data, it is not necessary to incorporate a nonvolatile memory. Furthermore, since the correction is performed at the time of measurement, it is not necessary to select the geomagnetic detection means at the time of manufacturing. Therefore, the manufacturing cost of the azimuth angle measuring device can be reduced as compared with the related art.
Furthermore, in the azimuth angle measuring device according to claim 7 according to the present invention, in the azimuth angle measuring device according to any one of claims 5 and 6, the ellipsoidal surface analysis means is repeatedly acquired by the detection output acquisition means. A three-axis output data group is arranged on the three-dimensional coordinates, and the length and center coordinates of each principal axis of the ellipsoid are statistically calculated so that the distance between the arranged measurement points and the ellipse is minimized. It is calculated by the following.
[0035]
With such a configuration, the ellipsoid analysis unit arranges the repeatedly obtained three-axis output data groups on the three-dimensional coordinates, and minimizes the distance between the arranged measurement points and the ellipsoid. , The length and the center coordinates of each principal axis of the ellipsoid are calculated by a statistical method.
Further, in the azimuth angle measuring device according to claim 8 of the present invention, in the azimuth angle measuring device according to claim 7, the ellipsoidal plane analyzing means obtains a convergent solution as an optimal solution by iterative calculation by giving an initial value. By a multi-dimensional optimization method, solve the error sum calculation formula for calculating the sum of values corresponding to the distances between the measurement points and the ellipsoid for all the measurement points, and determine the length and center of each principal axis of the ellipse. The coordinates are calculated.
[0036]
With such a configuration, the elliptical surface analysis means solves the error sum calculation expression by a multidimensional optimization method, and calculates the length and center coordinates of each principal axis of the elliptical surface. Here, the multidimensional optimization method is an optimization method in which an initial value is given and a convergent solution is obtained as an optimal solution by iterative calculation. Further, since the error sum calculation formula is a calculation formula for calculating the sum of values corresponding to the distances between the measurement points and the ellipsoid for all the measurement points, it corresponds to the length and the center coordinates of each principal axis of the ellipse. It is configured to include at least the variable that is set.
[0037]
Further, in the azimuth angle measuring device according to the ninth aspect of the present invention, in the azimuth angle measuring device according to the seventh aspect, the ellipsoidal surface analysis means obtains a convergent solution as an optimal solution by iterative calculation by giving an initial value. By a multi-dimensional optimization method, a first error calculation method for calculating the sum total of the errors corresponding to the distances between the measurement points and the elliptical surface for all the measurement points and calculating the center coordinates of the elliptical surface is first. The elliptic ellipse is calculated by an analysis process and an error sum partial differential operation formula obtained by partially differentiating the error total operation formula with a variable corresponding to the length of each of the principal axes of the ellipsoidal surface based on the value calculated in the first analysis process. A second analysis process for calculating the length of each principal axis of the surface and a third analysis process for repeatedly performing the first analysis process and the second analysis process until the value calculated in the second analysis process converges. It has become.
[0038]
With such a configuration, the first analysis processing, the second analysis processing, and the third analysis processing are performed by the ellipsoid analysis means.
In the first analysis processing, the error summation expression is solved by a multidimensional optimization method, and the center coordinates of the ellipsoid are calculated. Here, the multidimensional optimization method is an optimization method in which an initial value is given and a convergent solution is obtained as an optimal solution by iterative calculation. Further, since the error sum calculation formula is a calculation formula for calculating the sum of values corresponding to the distances between the measurement points and the ellipsoid for all the measurement points, it includes at least a variable corresponding to the center coordinates of the ellipse. Be composed.
[0039]
In the second analysis processing, the length of each principal axis of the ellipsoid is calculated by the error sum partial differential operation formula based on the value calculated in the first analysis processing. Here, the error sum partial differential equation is an arithmetic equation obtained by partially differentiating the error sum equation with a variable corresponding to the length of each principal axis of the elliptical surface. At least.
In the third analysis process, the first analysis process and the second analysis process are repeatedly performed until the value calculated in the second analysis process converges.
[0040]
Further, in the azimuth angle measuring apparatus according to claim 10 according to the present invention, in the azimuth angle measuring apparatus according to claim 7, the ellipsoidal plane analyzing means is configured to determine the measurement point and the ellipsoidal plane for all the measurement points. The length of each principal axis of the elliptical surface is initially set to a first error sum partial differential computing expression obtained by partially differentiating an error sum calculating expression for calculating a sum of values corresponding to distances with a variable corresponding to the center coordinates of the ellipsoid. Given as a value, a first analysis process for calculating the center coordinates of the elliptical surface by the first error sum partial differential operation expression, and the error sum operation expression is calculated based on the value calculated in the first analysis process. A second analysis process for calculating the length of each main axis of the elliptical surface by a second error sum partial differential operation formula partially differentiated by a variable corresponding to the length of each main axis of the ellipsoid; and the second analysis process. The first analysis processing is performed until the calculated value converges. Third and performs an analysis process performed repeatedly preliminary second analysis processing.
[0041]
With such a configuration, the first analysis processing, the second analysis processing, and the third analysis processing are performed by the ellipsoid analysis means.
In the first analysis process, the length of each principal axis of the ellipsoid is given to the first error sum partial differential equation as an initial value, and the center coordinate of the ellipsoid is calculated by the first error sum partial differential equation. Here, the first error sum partial differential equation is an arithmetic equation obtained by partially differentiating the error total equation with a variable corresponding to the center coordinate of the ellipsoid, and the error total equation is calculated for all the measurement points. Are arithmetic expressions for calculating the sum of values corresponding to the distance between the ellipsoid and the elliptical surface, and these arithmetic expressions include at least a variable corresponding to the central coordinates of the elliptical surface.
[0042]
In the second analysis process, the length of each principal axis of the elliptical surface is calculated by the second error sum partial differential operation formula based on the value calculated in the first analysis process. Here, the second error sum partial differential operation equation is an arithmetic expression obtained by partially differentiating the error sum operation equation with variables corresponding to the lengths of the respective main axes of the ellipsoid. It is configured to include at least the variable that is set.
[0043]
In the third analysis process, the first analysis process and the second analysis process are repeatedly performed until the value calculated in the second analysis process converges.
Further, in the azimuth angle measuring device according to claim 11 according to the present invention, in the azimuth angle measuring device according to any one of claims 5 to 10, the ellipsoidal surface analyzing means may include a degree of change in the three-axis output. When the degree of change is less than or equal to a predetermined value with respect to the minimum axis, each main axis is represented on a two-dimensional coordinate whose component is a specific two-axis output other than the three-axis output with the minimum degree of change. An ellipse parallel to each coordinate axis of the two-dimensional coordinates is determined, and the length of each principal axis of the ellipse and the length of each principal axis of the ellipse are determined based on the three-axis output data group repeatedly obtained by the detection output obtaining unit and related to the specific two-axis output. The center coordinates are calculated.
[0044]
With such a configuration, if the degree of change of the three-axis output having the smallest degree of change is equal to or less than a predetermined value, the ellipsoidal surface analysis means determines that the degree of change of the three-axis output is the smallest. Ellipses whose main axes are parallel to the respective coordinate axes of the two-dimensional coordinates are defined on the two-dimensional coordinates having a component of the specific two-axis output other than the specific two-axis output. Based on the object, the length and center coordinates of each principal axis of the ellipse are calculated.
[0045]
The azimuth measuring device according to the present invention, by moving and rotating the azimuth measuring device, repeatedly obtains three-axis output when the direction of the geomagnetism detecting means changes in the three-dimensional space a predetermined number of times or more. When the azimuth measuring device is moved or rotated only on a plane perpendicular to any one of the three axes of the geomagnetism detecting means (hereinafter, referred to as a specific axis in this paragraph), the output of the specific axis hardly changes. . Therefore, even if the length and center coordinates of each principal axis of the elliptical surface are calculated based on the three-axis output data group including the output data of the specific axis, those values may not be accurately obtained. In this case, it is more accurate to calculate the length and center coordinates of each main axis of the ellipse based on the two-axis output data group excluding the output data of the specific axis, as in the azimuth angle measuring device according to claim 11. Value is obtained.
[0046]
Furthermore, the azimuth angle measuring device according to claim 12 according to the present invention is the azimuth angle measuring device according to any one of claims 5 to 11, wherein the output correction means includes a main axis calculated by the ellipsoid analysis means. The sensitivity and offset of the three-axis output of the terrestrial magnetism detecting means are corrected based on the length and the central coordinates of the geomagnetic field.
With such a configuration, the sensitivity and offset of the three-axis output of the terrestrial magnetism detection unit are corrected by the output correction unit based on the calculated length and center coordinates of each main shaft.
[0047]
Further, in the azimuth angle measuring device according to claim 13 of the present invention, in the azimuth angle measuring device according to any one of claims 5 to 12, the ellipsoidal surface analysis means outputs each axis output by the detection output acquisition means. Is repeatedly obtained a predetermined number of times to calculate a difference between the maximum value and the minimum value in each axis output, and determines whether the difference calculated by the first difference calculation means is equal to or more than a predetermined value. A first difference judging means for judging, and when the difference calculated by the first difference calculating means is equal to or more than a predetermined value, the axis output obtained repeatedly by the detection output obtaining means a predetermined number of times is output to the axis. Target for ellipsoidal analysis.
[0048]
With such a configuration, when the orientation of the azimuth angle measurement device is stationary or has changed only slightly, the length and center coordinates of each main axis of the ellipsoid are calculated with a large error. It is possible to improve the accuracy of calculating the length and center coordinates of each principal axis of the elliptical surface, and keep the sensitivity and offset calibration accuracy high.
[0049]
Further, in the azimuth angle measuring device according to claim 14 according to the present invention, in the azimuth angle measuring device according to any one of claims 5 to 12, the output correction means includes an ellipse calculated by the ellipsoid analysis means. Variation of the length of each principal axis of the surface and the length of each principal axis of the ellipsoid previously calculated by the ellipsoidal analysis means, or the center coordinates of the ellipse calculated by the ellipsoidal analysis means and the ellipsoidal analysis means A variation calculation means for calculating the variation of the center coordinates of the ellipsoid calculated previously, the length of each principal axis of the ellipsoid calculated by the ellipsoid analysis means based on the calculation result of the variation calculation means and Discard center coordinates.
[0050]
With such a configuration, the elliptic ellipse is used when the detection output of the terrestrial magnetism includes a large error due to noise or the like, or when the orientation of the two-axis terrestrial magnetism detecting means changes from a predetermined plane. It is possible to prevent an inappropriate output correction by incorrectly calculating the length and center coordinates of each principal axis of the surface.
Further, an azimuth angle measuring device according to claim 15 of the present invention is obtained by the azimuth angle measuring device according to any one of claims 5 to 14 for azimuth angle measurement during execution of azimuth angle measurement. The calculation of the length and center coordinates of each principal axis of the elliptical surface and the output correction are performed in the background using each axis output, and the correction of each axis output is performed as needed.
[0051]
With such a configuration, it is possible for the user to automatically correct the output of each axis by measuring the azimuth angle.
Further, the azimuth angle measuring device according to claim 16 according to the present invention is the azimuth angle measuring device according to any one of claims 5 to 15, wherein the length of each principal axis of the elliptical surface calculated by the ellipsoidal analyzing means is set. And the variation of the length of each principal axis of the ellipsoid previously calculated by the ellipsoidal analysis means or the center coordinates of the ellipse calculated by the ellipsoidal analysis means and previously calculated by the ellipsoidal analysis means. A second variation calculating means for calculating the variation of the center coordinates of the elliptical surface, and a goodness for generating goodness information on goodness of correction by the output correcting means based on a calculation result by the second variation calculating means. Information creating means.
[0052]
With such a configuration, the variation between the calculated main axis length of the elliptical surface and the previously calculated main axis length of the elliptical surface or the center of the calculated elliptical surface is calculated by the second variation calculating means. The variation between the coordinates and the previously calculated center coordinate of the elliptical surface is calculated, and the goodness information creating means creates goodness information based on the calculation result of the variation.
[0053]
Further, in the azimuth angle measuring device according to claim 17 according to the present invention, in the azimuth angle measuring device according to claim 16, the goodness information creating means classifies the goodness of correction by the output correction means into a plurality of degrees. In addition, the information is classified into any of the categories according to the degree of variation calculated by the second variation calculating means, and goodness information indicating the degree of goodness corresponding to the category is created.
[0054]
With such a configuration, the goodness information creating unit classifies the information into one of the categories according to the calculated degree of variation, and creates goodness information indicating the goodness level corresponding to the category.
Further, in the azimuth angle measuring device according to claim 18 according to the present invention, in the azimuth angle measuring device according to any one of claims 5 to 17, the output correction means may determine the length of each axis of the elliptical surface. An axis length calculating means for calculating, and an axis length determining means for determining whether or not the length of each axis of the elliptical surface calculated by the axis length calculating means is outside a predetermined range. If the length of each axis of the elliptical surface is outside the predetermined range, the output data is discarded.
[0055]
With such a configuration, the length of each axis of the ellipsoid is calculated by the axis length calculation means, and the length of each axis of the calculated ellipse is determined by the axis length determination means to be outside the predetermined range. Is determined. If the calculated length of each axis of the ellipsoid is outside the predetermined range, the output data is discarded.
Furthermore, an azimuth angle measuring device according to claim 19 according to the present invention is the azimuth angle measuring device according to any one of claims 5 to 17, wherein the second axis for calculating the length of each axis of the elliptical surface is provided. Length calculating means, and reliability information creating means for creating reliability information on the reliability of the azimuth angle measurement result based on the length of each axis of the elliptical surface calculated by the second axis length calculating means. .
[0056]
With such a configuration, the length of each axis of the ellipsoid is calculated by the second axis length calculation means, and the reliability information creation means calculates the length of each axis of the ellipse according to the calculated length of each axis. Reliability information indicating the degree of reliability is created.
Further, in the azimuth angle measuring device according to claim 20 according to the present invention, in the azimuth angle measuring device according to claim 19, the reliability information creating means divides the reliability of the azimuth angle measurement result into a plurality. And comparing the length of each axis of the elliptical surface calculated by the second axis length calculation means with a plurality of thresholds, classifying the axis into one of the sections, and indicating the reliability corresponding to the section. Create information.
[0057]
With such a configuration, the calculated length of each axis of the ellipsoid is compared with a plurality of thresholds and classified into one of the sections by the reliability information creating unit, and the reliability corresponding to the section is calculated. The reliability information shown is created.
On the other hand, in order to achieve the above object, a calibration program according to claim 21 of the present invention is a program for causing a computer that can use three or more axes of terrestrial magnetism detecting means for detecting terrestrial magnetism to execute, Detection output acquisition means for repeatedly acquiring a three-axis output when the orientation of the geomagnetism detection means changes in a three-dimensional space a predetermined number of times or more; Ellipsoidal analysis means for determining an ellipsoid parallel to each coordinate axis of the dimensional coordinates, and calculating the length and center coordinates of each principal axis of the ellipse based on the three-axis output data group repeatedly acquired by the detection output acquisition means. And output correction means for correcting the three-axis output of the terrestrial magnetism detection means based on the length and center coordinates of each principal axis of the ellipsoid calculated by the ellipsoid analysis means. The process implemented is a program for causing the computer to perform.
[0058]
With such a configuration, when the program is read by the computer and the computer executes the processing in accordance with the read program, an operation equivalent to that of the azimuth angle measuring device according to claim 5 can be obtained.
Further, the calibration program according to claim 22 of the present invention is a program for causing a computer that can use two or more axes of geomagnetism detecting means for detecting geomagnetism to be executed, wherein the orientation of the geomagnetism detecting means is predetermined. A detection output acquisition means for repeatedly acquiring a two-axis output when it changes while maintaining it on the plane of a predetermined number of times or more, on a two-dimensional coordinate having the two-axis output as a component, An ellipse analyzing means for determining an ellipse parallel to each coordinate axis and calculating a length and a center coordinate of each principal axis of the ellipse based on a two-axis output data group repeatedly acquired by the detection output acquiring means; Based on the length and center coordinates of each principal axis of the ellipse calculated in the above, the processing realized as the output correction means for correcting the two-axis output of the geomagnetic detection means is previously described. Is a program for causing a computer to execute.
[0059]
With such a configuration, when the program is read by the computer and the computer executes the processing in accordance with the read program, an operation equivalent to that of the azimuth angle measuring device according to claim 6 is obtained.
On the other hand, in order to achieve the above object, a calibration method according to claim 23 according to the present invention comprises the steps of: changing a detection direction of three axes in geomagnetic measurement in a three-dimensional space; A step of obtaining a three-axis output of the geomagnetic measurement; a step of determining whether or not the three-axis output is obtained a predetermined number of times or more; and a three-dimensional coordinate having the three-axis output as a component. Determining an elliptical surface parallel to each coordinate axis, calculating the length and center coordinates of each principal axis of the elliptical surface based on the three-axis output data group acquired at least the predetermined number of times, Correcting the three-axis output based on the length and center coordinates of the main shaft.
[0060]
Further, the calibration method according to claim 24 according to the present invention includes the steps of changing the two-axis detection directions in the geomagnetic measurement while keeping the detection directions on a predetermined plane, and performing the geomagnetic measurement when the detection directions change. Acquiring a two-axis output; determining whether the acquisition of the two-axis output is equal to or greater than a predetermined number of times; Determining a parallel ellipse and calculating the length and center coordinates of each principal axis of the ellipse based on the biaxial output data group acquired at least the predetermined number of times; and calculating the length and center of each principal axis of the calculated ellipse Correcting the two-axis output based on the coordinates.
[0061]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. 1 to 3 are diagrams showing a first embodiment of a measuring device, an azimuth measuring device, a calibration program, and a calibration method according to the present invention.
In the present embodiment, the measuring device, the azimuth measuring device, the calibration program, and the calibration method according to the present invention are used to correct the sensitivity and offset of the three-axis magnetic sensor 11 of the portable device 201 as shown in FIG. This applies to the case where
[0062]
FIG. 1 is a perspective view showing a perspective configuration of a portable device 201 to which the present invention is applied.
In FIG. 1, a portable device 201 is provided with a display unit 202 and an antenna 203, and has a built-in azimuth measuring device for measuring terrestrial magnetism in each of three axes to obtain an azimuth.
[0063]
Here, the azimuth angle measuring device includes an x-axis Hall element HEx measuring the x-direction component Mx of the geomagnetism M, a y-axis Hall element HEy measuring the y-direction component My of the geomagnetism M, and a z-direction component Mz of the geomagnetism M. A z-axis Hall element HEz to be measured is provided, and the x-axis Hall element HEx, the y-axis Hall element HEy, and the z-axis Hall element HEz are arranged such that each magneto-sensitive surface is perpendicular to each axis.
[0064]
FIG. 2 is a block diagram showing a schematic configuration of the azimuth angle measuring device according to the present invention.
2, the azimuth angle measuring device includes a three-axis magnetic sensor 11, a magnetic sensor drive power supply unit 12, a chopper unit 13, a differential input amplifier 14, an A / D conversion unit 15, a correction calculation unit 16, an azimuth calculation unit. 17, an offset / sensitivity correction coefficient calculating unit 18, an offset information storage unit 19a, and a sensitivity correction information storage unit 19b. The three-axis magnetic sensor 11 includes an x-axis Hall element HEx, a y-axis Hall element HEy, and a z-axis Hall An element HEz is provided.
[0065]
The x-axis Hall element HeEx, the y-axis Hall element HEy, and the z-axis Hall element HEz are for detecting terrestrial magnetism, and are preferably, for example, a compound semiconductor based on InSb, InAs, GaAs or the like or a Si monolithic. .
The chopper section 13 is for switching terminals for driving the x-axis Hall element HEx, the y-axis Hall element HEy, and the z-axis Hall element HEz, respectively. The chopper section 13 converts the drive voltage output from the magnetic sensor drive power supply section 12 into the x-axis. The Hall element HEx, the y-axis Hall element HEy, and the z-axis Hall element HEz are respectively applied to the Hall element HEx, the signals output from the x-axis Hall element HEx, the y-axis Hall element HEy, and the z-axis Hall element HEz are differentially input in a time division manner. Output to the amplifier 14.
[0066]
Here, the chopper section 13 can use, for example, 90 ° chopper drive or 360 ° chopper drive. In the 90 ° chopper drive, when the x-axis Hall element HEx, the y-axis Hall element HEy, and the z-axis Hall element HEz are driven, the output of the x-axis Hall element HEx, the y-axis Hall element HEy, and the z-axis Hall element HEz Can largely cancel the offset term of the Hall element itself included in.
[0067]
In the 360 ° chopper drive, not only the offset term of the Hall element itself included in the output of the x-axis Hall element HEx, the y-axis Hall element HEy, and the z-axis Hall element HEz, but also the electric current generated by the differential input amplifier 14 itself at the subsequent stage. Dynamic offset term can be easily canceled.
The signals output from the x-axis Hall element HeEx, the y-axis Hall element HEy, and the z-axis Hall element HEz are respectively amplified by the differential input amplifier 14, and the amplified output value is converted to an A / D converter. After being converted into a digital signal at 15, it is input to the correction calculation unit 16.
[0068]
Here, the output amplification value Srx of the x-axis Hall element HEx can be expressed by the following equation (5), the output amplification value Sry of the y-axis Hall element HEy can be expressed by the following equation (6), and z The output amplification value Srz of the axis Hall element HEz can be expressed by the following equation (7).
[0069]
(Equation 1)

[0070]
(Equation 2)

[0071]
(Equation 3)

[0072]
Where ax is the sensitivity [V / T] of the x-axis Hall element HEx, Crx is the offset [V] of the x-axis Hall element HEx, ay is the sensitivity [V / T] of the y-axis Hall element HEy, and Cry is , The offset [V] of the y-axis Hall element HEy, az is the sensitivity [V / T] of the z-axis Hall element HEz, Crz is the offset [V] of the z-axis Hall element HEz, and Mx is the x direction of the geomagnetism M The components [T] and My are the y-direction component [T] of the geomagnetism M, and Mz is the z-direction component [T] of the geomagnetism M.
[0073]
The offset information storage unit 19a stores offsets of the x-axis Hall element HEx, the y-axis Hall element HEy, and the z-axis Hall element HEz as offset information, and the sensitivity correction information storage unit 19b stores the x-axis Hall element HEx. Sensitivity correction coefficients for correcting variations of the Hall element HEx, the y-axis Hall element HEy, and the z-axis Hall element HEz are stored as sensitivity correction information.
[0074]
During the execution of the azimuth measurement, the correction calculation unit 16 uses the offset information and the sensitivity correction information to obtain the output amplification values Srx, Sry of the x-axis Hall element HEx, the y-axis Hall element HEy, and the z-axis Hall element HEz. , Srz are respectively corrected, and only the x-, y-, and z-axis components Mx, My, and Mz of the geomagnetism M are extracted and output to the azimuth calculator 17.
[0075]
Then, the azimuth calculator 17 calculates the signs of the x, y, and z axis components Mx, My, and Mz of the geomagnetism M, and θ = tan^-1The azimuth angle θ is calculated based on the expression (My / Mx).
During the execution of the calibration, the output amplification values Srx, Sry, and Srz of the x-axis Hall element HEx, the y-axis Hall element HEy, and the z-axis Hall element HEz are output to the offset / sensitivity correction coefficient calculation unit 18.
[0076]
When the orientation of the portable device 201 is arbitrarily changing in the three-dimensional space, the offset / sensitivity correction coefficient calculation unit 18 calculates the output amplification values of the x-axis Hall element HEx, the y-axis Hall element HEy, and the z-axis Hall element HEz. Srx, Sry, and Srz are acquired a predetermined number of times or more, and the sensitivity correction coefficients and offsets of the x-axis Hall element HEx, the y-axis Hall element HEy, and the z-axis Hall element HEz are determined based on the acquired output amplification values Srx, Sry, and Srz. The calculated sensitivity correction coefficient is stored in the sensitivity correction information storage unit 19b, and the calculated offset is stored in the offset information storage unit 19a.
Next, a method of calculating the sensitivity correction coefficient and the offset will be described.
First, the sensitivity correction coefficient is defined by the following equation (8).
[0077]
(Equation 4)

[0078]
Here, αx is the sensitivity correction coefficient of the x-axis Hall element HEx, αy is the sensitivity correction coefficient of the y-axis Hall element HEy, αz is the sensitivity correction coefficient of the z-axis Hall element HEz, and a0 is the three-axis after sensitivity correction. This is the sensitivity [V / T] of the magnetic sensor 11.
Further, the output amplification value and offset of the three-axis magnetic sensor 11 after the sensitivity correction are defined by the following equations (9) to (14).
[0079]
(Equation 5)

[0080]
(Equation 6)

[0081]
(Equation 7)

[0082]
(Equation 8)

[0083]
(Equation 9)

[0084]
(Equation 10)

[0085]
Here, Sx is the output amplification value [V] after the sensitivity correction of the x-axis Hall element HEx, Cx is the offset [V] after the sensitivity correction of the x-axis Hall element HEx, and Sy is the sensitivity of the y-axis Hall element HEy. The corrected output amplification value [V] and Cy are the offset [V] after the sensitivity correction of the y-axis Hall element HEy, and Sz is the output amplification value [V] and the Cz of the z-axis Hall element HEz after the sensitivity correction. , The offset [V] after the sensitivity correction of the z-axis Hall element HEz.
By substituting the above equations (9) to (14) into the above equations (5) to (7), the following equations (15) to (17) are obtained.
[0086]
(Equation 11)

[0087]
(Equation 12)

[0088]
(Equation 13)

[0089]
On the other hand, geomagnetism is defined by the following equation (18).
[0090]
[Equation 14]

[0091]
Here, M is geomagnetism [T].
During the execution of the calibration, if only the orientation of the portable device 201 changes and there is no movement of the place, the geomagnetism M can be regarded as a constant value. Therefore, when the above equations (15) to (17) are modified and substituted into the above equation (18), the following equation (19) is obtained.
[0092]
[Equation 15]

[0093]
That is, in the orthogonal coordinate system (x, y, z), the point (Sx, Sy, Sz) is always located at a fixed distance a0M from the point (Cx, Cy, Cz).
FIG. 3 is a diagram illustrating the concept of the calibration method.
In FIG. 3, measurement data obtained by measuring the geomagnetism M N times while directing the portable device 201 in various directions is used to calculate the output amplification value of the x-axis Hall element HEx before the sensitivity correction is S1rx. , S2rx,..., SNrx [V], the output amplification value of the y-axis Hall element HEy before the sensitivity correction is S1ry, S2ry,..., SNry [V], and the output of the z-axis Hall element HEz before the sensitivity correction. The amplification values are S1rz, S2rz,..., SNrz [V]. Further, the measurement points P1 (S1rx, S1ry, S1rz), P2 (S2rx, S2ry, S2rz),. Respectively.
[0094]
Assuming that the sensitivity correction coefficients αx, αy, and αz are known, and the scaling of the following equations (20) to (22) is performed for each axis of the orthogonal coordinate system (x, y, z), the orthogonal coordinate system ( The measurement points P1, P2,..., PN in (x, y, z) are converted as shown in the following equations (23) to (25) in the scaled rectangular coordinate system (x ′, y ′, z ′). You.
[0095]
(Equation 16)

[0096]
[Equation 17]

[0097]
(Equation 18)

[0098]
[Equation 19]

[0099]
(Equation 20)

[0100]
(Equation 21)

[0101]
However, S1x, S2x,..., SNx are obtained by the following equation (26), S1y, S2y,... SNy are obtained by the following equation (27), and S1z, S2z,. Is obtained by
[0102]
(Equation 22)

[0103]
(Equation 23)

[0104]
[Equation 24]

[0105]
.., SNx are output amplification values [V] of the x-axis Hall element HEx after sensitivity correction, and S1y, S2y,..., SNy are output amplification values of the y-axis Hall element HEy after sensitivity correction. [V], S1z, S2z,..., SNz are output amplification values [V] of the z-axis Hall element HEz after sensitivity correction. , MNx are geomagnetic x-axis components [T], M1y, M2y,..., MNy are geomagnetic y-axis components [T], M1z, M2z,. , The component [T] of the geomagnetism in the z-axis direction.
Then, the following equation (29) is obtained from the above equation (18), and the following equation (30) is obtained from the above equation (19).
[0106]
(Equation 25)

[0107]
(Equation 26)

[0108]
That is, in the scaled rectangular coordinate system (x ′, y ′, z ′), the measurement points P1 ′, P2 ′,..., PN ′ all have a fixed distance a0M as viewed from the point (Cx, Cy, Cz). Will be located.
Further, when the above equations (12) to (14) and the above equations (26) to (28) are modified and substituted into the above equation (30), the following equation (31) is obtained.
[0109]
[Equation 27]

[0110]
That is, in the rectangular coordinate system (x, y, z), each of the measurement points P1, P2,..., PN has its main axis parallel to each coordinate axis of the rectangular coordinate system (x, y, z) and the length of each main axis. Are a0M / αx, a0M / αy, and a0M / αz, and the center coordinates are located on the elliptical surface of (Crx, Cry, Crz).
Therefore, from a different perspective, the following can be said.
[0111]
.., PN are distributed in a rectangular coordinate system (x, y, z), and appropriate scaling factors αx, αy, αz are set, and the above equations (20) to (22) are used. As a result of scaling the rectangular coordinate system (x, y, z), a point (all points of the measurement points P1 ′, P2 ′,..., PN ′ in the scaled rectangular coordinate system (x ′, y ′, z ′)) Cx, Cy, Cz). At this time, αx, αy, αz correspond to the sensitivity correction coefficient, and Cx, Cy, Cz correspond to the offset after the sensitivity correction.
[0112]
Alternatively, in the rectangular coordinate system (x, y, z), when each principal axis sets an elliptical surface parallel to each coordinate axis of the rectangular coordinate system (x, y, z), the measurement points P1, P2,. Suppose everything is now on an ellipsoid. At this time, the lengths of the respective main axes correspond to the sensitivity correction coefficients αx, αy, αz, and the coefficients a0M / αx, a0M / αy, a0M / αz composed of the sensitivity α0 of the magnetic sensor after the sensitivity correction and the geomagnetism M, and the center coordinates. Corresponds to the offsets Crx, Cry, Crz before the sensitivity correction.
[0113]
Based on the above concept, a method of calculating the sensitivity correction coefficients αx, αy, αz and the offsets Cx, Cy, Cz from the measurement data can be derived. The information required in the azimuth angle calculation is the ratio of the components of the geomagnetism in the x, y, and z-axis directions, and is not an absolute value. Therefore, it is not necessary to calculate a0 and M, and frequently appear in the above equations. In the obtained a0M, an arbitrary value convenient for calculation may be set.
[0114]
In the following specific example, one of Cx, Cy, Cz or Crx, Cry, Crz is appropriately calculated in order to minimize the complexity of the mathematical expression. 12) to (14), and have the same meaning.
If it is assumed that the error included in the output amplification value of the three-axis magnetic sensor 11 is almost negligible, the mobile device 201 may be directed in any of six different directions and the geomagnetism may be measured.
[0115]
The above equation (31) gives αx², Αy², Αz²And six-dimensional simultaneous equations relating to the offsets Crx, Cry, and Crz, which are difficult to solve analytically, but can be solved by numerical calculation (for example, Newton-Raphson method).
When the above equation (31) is modified using the following equations (32) and (33), a five-dimensional non-linear simultaneous equation relating to p and q and offsets Cx, Cy and Cz as shown in the following equation (34) is obtained. be able to.
[0116]
[Equation 28]

[0117]
(Equation 29)

[0118]
[Equation 30]

[0119]
Since the above equation (34) has one less dimension than the above equation (31), the amount of calculation can be reduced.
On the other hand, it should be noted that the actually measured terrestrial magnetism intensity is on the order of 0.01 [mT], and is extremely weak, so that the output amplification value of the three-axis magnetic sensor 11 is considerably large. That is, noise is included.
[0120]
Therefore, it is necessary to increase the number of measurements N as much as possible, and to calculate the sensitivity correction coefficients αx, αy, αz and the offsets Cx, Cy, Cz using a statistical method. A specific example will be described below.
Assuming that the sensitivity correction coefficients αx, αy, αz and the offsets Crx, Cry, Crz have been calculated, the measurement point Pi ′ corresponding to the i-th measurement data in the orthogonal coordinate system (x ′, y ′, z ′) after scaling. The distance di from (Six, Siy, Siz) to the point (Cx, Cy, Cz) is obtained by the following equation (35).
[0121]
[Equation 31]

[0122]
If the measurement data does not contain noise and the sensitivity correction coefficients αx, αy, αz and the offsets Crx, Cry, Crz are correctly calculated, di = a0M for all the measurement data. . However, actually, the two are not equal because the measurement data includes noise. Therefore, the measurement error and the sum of squares for the i-th measurement data are defined by the following equations (36) and (37).
[0123]
(Equation 32)

[0124]
[Equation 33]

[0125]
When the above equations (12) to (14) and the above equations (26) to (28) are modified and substituted into the above equation (37), the following equation (38) is obtained.
[0126]
[Equation 34]

[0127]
It is appropriate to calculate the sensitivity correction coefficients αx, αy, αz and the offsets Crx, Cry, Crz such that the sum of squares S is minimized.
Next, a method of calculating the sensitivity correction coefficients αx, αy, αz and the offsets Crx, Cry, Crz such that the sum of squares S is minimized will be described.
Minimizing S in the above equation (38) using a multidimensional optimization method (for example, a conjugate gradient method) with all of the sensitivity correction coefficients αx, αy, αz and offsets Crx, Cry, Crz as independent variables. Can be. The conjugate gradient method is described in “WH Press, SA Teukolsky, WT Vetterling and BP Plannery,” “Numerical Recipes in C, Second Edition,” “Cambridge, United States, 1992, United States, United States, United States, 1992, United States, United States, United States, United States, United States, 1992, United States, United States, United States, United States, United States, 1992, United States, United States, United States, United States, United States, United States, 1992, 1992 Pp. 420-425 ".
[0128]
When the conjugate gradient method is used as the multidimensional optimization method, it is necessary to calculate the derivative of S by each independent variable. However, the above equation (38) is calculated by using the sensitivity correction coefficients αx, αy, αz and the offsets Crx, Cry, The following equations (39) to (44) which are partially differentiated by Crz may be used.
[0129]
(Equation 35)

[0130]
[Equation 36]

[0131]
(37)

[0132]
[Equation 38]

[0133]
[Equation 39]

[0134]
(Equation 40)

[0135]
The calculation method using the conjugate gradient method has a simpler procedure than the calculation methods in the second and third embodiments, and is convenient when it is desired to reduce the number of program steps.
Next, the operation of the present embodiment will be described.
When performing calibration, if the direction of the portable device 201 is changed to an arbitrary direction by moving or rotating the portable device 201, the orientation of the three-axis magnetic sensor 11 is changed to a three-dimensional space by the offset / sensitivity correction coefficient calculation unit 18. The three-axis output at the time of the change is repeatedly obtained a predetermined number of times or more. Next, on the rectangular coordinate system (x, y, z), an elliptical surface in which each principal axis is parallel to each coordinate axis of the rectangular coordinate system (x, y, z) is defined. (x, y, z), and the length and center coordinates of each principal axis of the ellipsoid are calculated by a statistical method such that the distance between each of the arranged measurement points and the ellipse is minimized. More specifically, the sensitivity correction coefficients αx, αy, αz and the offsets Crx, Cry, Crz, which are the center coordinates of the elliptical surface, are calculated by minimizing S in the above equation (38) by the conjugate gradient method. Then, the calculated sensitivity correction coefficients αx, αy, αz are stored in the sensitivity correction information storage unit 19b, and the calculated offsets Crx, Cry, Crz are stored in the offset information storage unit 19a.
[0136]
When measuring the azimuth angle, the x-axis Hall element is calculated by the correction calculating unit 16 based on the sensitivity correction coefficients αx, αy, αz of the sensitivity correction information storage unit 19b and the offsets Crx, Cry, Crz of the offset information storage unit 19a. The output amplification values Srx, Sry, and Srz of the HEx, y-axis Hall element HEy, and z-axis Hall element HEz are respectively corrected, and only the x, y, and z-axis components Mx, My, and Mz of the geomagnetism M are extracted, and the azimuth angle is calculated. Output to the unit 17. Then, the azimuth angle calculator 17 calculates the signs of the x, y, and z axis components Mx, My, and Mz of the geomagnetism M, and θ = tan.^-1The azimuth θ is calculated based on the expression (My / Mx).
[0137]
In this manner, in the present embodiment, when the orientation of the three-axis magnetic sensor 11 changes in the three-dimensional space, the three-axis output is repeatedly acquired a predetermined number of times or more, and is obtained on the orthogonal coordinate system (x, y, z). In addition, each principal axis defines an elliptical surface parallel to each coordinate axis of the rectangular coordinate system (x, y, z), and the measurement data obtained repeatedly is arranged on the rectangular coordinate system (x, y, z), and The sensitivity correction coefficients αx, αy, αz and the offsets Crx, Cry, Crz, which are the center coordinates of the ellipsoid, are calculated by a statistical method so that the distance between the measurement point and the ellipsoid is minimized.
[0138]
Thus, the sensitivity or offset of the three-axis magnetic sensor 11 can be corrected by simply changing the direction of the portable device 201 to an arbitrary direction. The offset can be corrected simply and accurately, and the offset of the three-axis magnetic sensor 11 can be corrected relatively easily. In addition, since it is not necessary to incorporate a nonvolatile memory into the portable device 201 and it is not necessary to select the three-axis magnetic sensor 11 during manufacturing, the manufacturing cost of the portable device 201 can be reduced as compared with the related art. .
[0139]
Further, in this embodiment, the sensitivity correction coefficients αx, αy, αz and the offsets Crx, Cry, Crz are calculated by minimizing S in the above equation (38) by the conjugate gradient method.
Thus, even if the measurement data includes an error, the sensitivity correction coefficients αx, αy, αz and the offsets Crx, Cry, Crz can be calculated relatively accurately. Therefore, the sensitivity or offset of the three-axis magnetic sensor 11 can be more accurately corrected.
[0140]
In the first embodiment, the three-axis magnetic sensor 11 corresponds to the detecting means according to claim 1 or 2, or the terrestrial magnetism detecting means according to claim 5, 12, or 21. The offset / sensitivity correction coefficient calculation unit 18 corresponds to the output correction unit described in claim 1, 2, 5, 12, or 21, or the detection output acquisition unit described in claim 1, 2, 5, 7, or 21. 1, 2, 5, 7, 8, 12, or 21. Further, the measurement data corresponds to the three-axis output data group described in claim 1, 2, 5, 7, 21, or 23, and the conjugate gradient method corresponds to the multidimensional optimization method described in claim 8. .
[0141]
Next, a second embodiment of the present invention will be described. Hereinafter, only portions different from the above-described first embodiment will be described, and portions overlapping with the above-described first embodiment will be denoted by the same reference numerals and description thereof will be omitted.
In the present embodiment, the measuring device, the azimuth measuring device, the calibration program, and the calibration method according to the present invention are used to correct the sensitivity and offset of the three-axis magnetic sensor 11 of the portable device 201 as shown in FIG. This embodiment is applied to the case where the calculation is performed, and differs from the first embodiment in that another calculation method is adopted as a method of minimizing S in the above equation (38).
[0142]
A method of calculating the sensitivity correction coefficients αx, αy, αz and the offsets Crx, Cry, Crz so that S in the above equation (38) is minimized will be described.
In the above equations (39) to (41), when S in the above equation (38) is minimum, the right side becomes zero as shown in the following equations (45) to (47).
[0143]
(Equation 41)

[0144]
(Equation 42)

[0145]
[Equation 43]

[0146]
When the above equations (45) to (47) are expressed by a matrix, the following equation (48) is obtained.², Αy², Αz²It can be seen that this is a system of linear equations.
[0147]
[Equation 44]

[0148]
Therefore, the sensitivity correction coefficients αx, αy, αz and the offsets Crx, Cry, Crz can be calculated in the following steps (1) to (4).
(1) Set appropriate initial values for the sensitivity correction coefficients αx, αy, αz.
(2) Using offsets Crx, Cry, and Crz as independent variables, minimize S in the above equation (38) using a multidimensional optimization technique. When the conjugate gradient method is used as the multidimensional optimization method, the above equations (42) to (44) may be calculated as the derivative of S.
(3) By solving the above equation (48), αx², Αy², Αz²Is calculated.
(4) It is determined whether or not the sensitivity correction coefficients αx, αy, αz have converged, and if it is determined that they have not converged, steps (2) and (3) are repeated.
[0149]
As described above, in the present embodiment, the step (1) of setting the initial values for the sensitivity correction coefficients αx, αy, and αz and the offset Crx, Cry, Step (2) for calculating Crz, step (3) for calculating sensitivity correction coefficients αx, αy, αz by solving the above equation (48) which is a simultaneous linear equation, and sensitivity correction coefficient calculated in step (3) and (4) repeating steps (2) and (3) until αx, αy, and αz converge.
[0150]
As a result, only the sensitivity correction coefficients αx, αy, and αz are calculated by the multidimensional optimization method, so that a convergent solution can be obtained faster than in the calculation method in the first embodiment. Therefore, the sensitivity correction coefficients αx, αy, αz and the offsets Crx, Cry, Crz can be calculated relatively quickly.
[0151]
In the second embodiment, the three-axis magnetic sensor 11 corresponds to the detecting means described in claim 1 or 2, or the terrestrial magnetism detecting means described in claim 5, 12, or 21. The offset / sensitivity correction coefficient calculation unit 18 corresponds to the output correction unit described in claim 1, 2, 5, 12, or 21, or the detection output acquisition unit described in claim 1, 2, 5, 7, or 21. 1, 2, 5, 7, 9, 12, or 21. The measurement data corresponds to the three-axis output data group described in claim 1, 2, 5, 7, 21, or 23, and the conjugate gradient method corresponds to the multidimensional optimization method described in claim 9, (2) corresponds to the first analysis processing according to claim 9, and step (3) corresponds to the second analysis processing according to claim 9.
[0152]
In the second embodiment, step (4) corresponds to the third analysis processing according to the ninth aspect.
Next, a third embodiment of the present invention will be described. Hereinafter, only portions different from the above-described first embodiment will be described, and portions overlapping with the above-described first embodiment will be denoted by the same reference numerals and description thereof will be omitted.
[0153]
In the present embodiment, the measuring device, the azimuth measuring device, the calibration program, and the calibration method according to the present invention are used to correct the sensitivity and offset of the three-axis magnetic sensor 11 of the portable device 201 as shown in FIG. This embodiment is applied to the case where the calculation is performed, and differs from the first embodiment in that another calculation method is adopted as a method of minimizing S in the above equation (38).
[0154]
A method of calculating the sensitivity correction coefficients αx, αy, αz and the offsets Crx, Cry, Crz so that S in the above equation (38) is minimized will be described.
When the above equation (37) is partially differentiated by offsets Cx, Cy, Cz, a0M, the following equations (49) to (52) are obtained.
[0155]
[Equation 45]

[0156]
[Equation 46]

[0157]
[Equation 47]

[0158]
[Equation 48]

[0159]
In the above equations (49) to (52), when S in the above equation (37) is minimum, the right side becomes zero. Therefore, the following equations (53) to (56) are obtained.
[0160]
[Equation 49]

[0161]
[Equation 50]

[0162]
(Equation 51)

[0163]
(Equation 52)

[0164]
When the above equation (56) is substituted into the above equations (53) to (55), the following equations (57) to (59) are obtained, and simultaneous linear equations relating to the offsets Cx, Cy, and Cz are derived.
[0165]
(Equation 53)

[0166]
(Equation 54)

[0167]
[Equation 55]

[0168]
However, the values of the above equations (57) to (59) are obtained by the following equations (60) to (77).
[0169]
[Equation 56]

[0170]
[Equation 57]

[0171]
[Equation 58]

[0172]
[Equation 59]

[0173]
[Equation 60]

[0174]
[Equation 61]

[0175]
(Equation 62)

[0176]
[Equation 63]

[0177]
[Equation 64]

[0178]
[Equation 65]

[0179]
[Equation 66]

[0180]
[Equation 67]

[0181]
[Equation 68]

[0182]
[Equation 69]

[0183]
[Equation 70]

[0184]
[Equation 71]

[0185]
[Equation 72]

[0186]
[Equation 73]

[0187]
Therefore, the sensitivity correction coefficients αx, αy, αz and the offsets Crx, Cry, Crz can be calculated in the following steps (1) to (4).
(1) Set appropriate initial values for the sensitivity correction coefficients αx, αy, αz.
(2) From equations (26) to (28), S1rx, S2rx,..., SNrx, S1ry, S2ry,. ,..., SNy, S1z, S2z,.
(3) The offsets Cx, Cy and Cz are calculated by solving the above equations (57) to (59).
(4) The offsets Crx, Cry, Crz are calculated from the offsets Cx, Cy, Cz by the above equations (12) to (14).
(5) By solving the above equation (48), αx², Αy², Αz²Is calculated.
(6) It is determined whether or not the sensitivity correction coefficients αx, αy, αz have converged. If it is determined that the sensitivity correction coefficients αx, αy, αz have not converged, steps (2) to (5) are repeated.
[0188]
As described above, in the present embodiment, the steps (1) to (4) for calculating the offsets Crx, Cry, and Crz by the above equations (57) to (59) and the steps (1) to (4) are performed. (5) for calculating the sensitivity correction coefficients αx, αy, αz by the above equation (48) based on the obtained values, and steps (2) to (2) until the values calculated in steps (1) to (4) converge. (6) repeatedly performing 5).
[0189]
As a result, a convergence solution can be obtained faster than in the calculation method according to the second embodiment. Therefore, the sensitivity correction coefficients αx, αy, αz and the offsets Crx, Cry, Crz can be calculated relatively quickly.
In the third embodiment, the three-axis magnetic sensor 11 corresponds to the detecting means according to claim 1 or 2, or the terrestrial magnetism detecting means according to claim 5, 12, or 21, and the correction calculation unit 16 The offset / sensitivity correction coefficient calculation unit 18 corresponds to the output correction means described in claim 1, 2, 5, 12, or 21, or the detection output acquisition means described in claim 1, 2, 5, 7, or 21. It corresponds to the elliptic surface analysis means described in 1, 2, 5, 7, 10, 12, or 21. Further, the measurement data corresponds to the three-axis output data group described in claims 1, 2, 5, 7, 21, or 23, and steps (1) to (4) correspond to the first analysis processing described in claim 10. Correspondingly, step (5) corresponds to the second analysis processing according to claim 10, and step (6) corresponds to the third analysis processing according to claim 10.
[0190]
Although the first to third embodiments have been described on the assumption that the azimuth measuring device is incorporated in the portable device 201, the portable device 201 such as a PDA (Personal Digital Assistant) or a notebook personal computer is described. The azimuth measuring device may be accommodated in a container that can be inserted and removed (removable) with respect to the azimuth angle measuring device, and the azimuth measuring device may be mounted on the portable device 201 for use.
[0191]
For example, an azimuth measuring device, its data processing IC, an interface IC, and the like are provided in a PCMCIA card inserted into a PC card slot provided as standard equipment in a notebook personal computer, and the above-described calibration function is incorporated as a driver thereof. You may do so.
Although the PC card slot has standards for mechanical and electrical characteristics, there is no standard for magnetic characteristics such as leakage magnetic flux density inside the slot, so the azimuth measuring device provided in a general-purpose PCMCIA card is In addition, the leakage magnetic flux density generated from a notebook computer cannot be predicted in advance.
[0192]
Here, by incorporating the calibration function of the azimuth angle measurement device into the PCMCIA card, even when the leakage magnetic field of the PC card slot varies for each portable device 201, the offset of the azimuth angle measurement device can be accurately corrected. Thus, the azimuth measuring device can be freely mounted and used without being limited to the specific portable device 201.
[0193]
The PCMCIA card may be equipped with an inclination sensor, a GPS (Global Positioning System) signal processing IC, an antenna, and the like in addition to the azimuth angle measurement device. The present invention is not limited to the card, and may correspond to the CF card slot.
Further, in the first to third embodiments, the case where the Hall element is used as the magnetic sensor has been described as an example. However, the magnetic sensor is not necessarily limited to the Hall element. You may make it use etc.
[0194]
Further, in the first to third embodiments, the offset / sensitivity correction coefficient calculating unit 18 determines that each principal axis is in the rectangular coordinate system (x, y, z) on the rectangular coordinate system (x, y, z). The elliptical surface parallel to each coordinate axis is determined, and the sensitivity correction coefficients αx, αy, αz and the offsets Crx, Cry, Crz are calculated based on the repeatedly acquired measurement data. Among the amplification values Sx, Sy, and Sz, when the degree of change is smaller than or equal to a predetermined value, the coordinate axis corresponding to the output amplification value whose degree of change is equal to or smaller than a predetermined value is a specific axis. Ellipses whose axes are parallel to each coordinate axis of the two-dimensional rectangular coordinate system are defined on a two-dimensional rectangular coordinate system obtained by removing specific axes from the rectangular coordinate system (x, y, z), and output amplification values Sx, Sy, Sz Other than those corresponding to the specific axis Based on those, the sensitivity correction coefficient .alpha.x, .alpha.y, .alpha.z and offset Crx, Cry, also be configured to calculate the other than those corresponding to a particular axis of the CRZ.
[0195]
Thus, even when the azimuth measuring device is moved or rotated only on a plane perpendicular to any one of the three axes of the three-axis magnetic sensor 11, the sensitivity correction coefficients αx, αy, αz and Of the offsets Crx, Cry, and Crz, those that correspond to two axes parallel to the plane on which the azimuth angle measurement device is moved or rotated can be calculated relatively accurately.
[0196]
In this case, the offset / sensitivity correction coefficient calculation unit 18 corresponds to the detection output acquisition unit or the ellipsoid analysis unit according to claim 11, and the measurement data is output from the three-axis output unit according to claim 11. It corresponds to a data group.
Further, in the first to third embodiments, the case where the processing performed by the offset / sensitivity correction coefficient calculating unit 18 is realized by hardware has been described. However, the present invention is not limited to this. The ROM and the RAM may be configured as a computer connected to a bus, and the CPU may execute these processes. In this case, a configuration may be adopted in which a control program stored in advance in the ROM is executed, but the program is read from the storage medium storing the program indicating these procedures into the RAM and executed. You may.
[0197]
Here, the storage medium is a semiconductor storage medium such as a RAM or a ROM, a magnetic storage type storage medium such as an FD or HD, an optical read type storage medium such as a CD, CDV, LD, or DVD, or a magnetic storage type storage such as an MO. / Optical reading type storage media, including any storage media that can be read by a computer, regardless of an electronic, magnetic, optical, or other reading method.
[0198]
In the first to third embodiments, the measuring device, the azimuth measuring device, the calibration program, and the calibration method according to the present invention, as shown in FIG. The present invention is applied to the case where the sensitivity and the offset of the magnetic sensor 11 are corrected. However, the present invention is not limited to this, and can be applied to other cases without departing from the gist of the present invention.
[0199]
【The invention's effect】
As described above, according to the measuring device according to claim 1 or 3 of the present invention, the sensitivity of the detecting means can be corrected only by changing the direction of the measuring device to an arbitrary direction. In comparison, the effect that the sensitivity of the detection means can be corrected relatively easily and accurately is obtained. In addition, there is no need to incorporate a nonvolatile memory, and it is not necessary to select the detecting means at the time of manufacturing, so that an effect that the manufacturing cost of the measuring device can be reduced as compared with the related art can be obtained.
[0200]
Furthermore, according to the measuring device according to claim 2 or 4 of the present invention, the offset of the detecting means can be corrected only by changing the direction of the measuring device to an arbitrary direction. The effect is obtained that the offset of the detection means can be corrected relatively easily.
On the other hand, according to the azimuth angle measuring device according to claims 5 to 20 of the present invention, the sensitivity or offset of the terrestrial magnetism detecting means can be corrected only by changing the direction of the azimuth angle measuring device to an arbitrary direction. As compared with the related art, it is possible to obtain the effect that the sensitivity of the geomagnetism detecting means can be corrected relatively easily and accurately, and the offset of the geomagnetic detection means can be corrected relatively easily. In addition, since it is not necessary to incorporate a nonvolatile memory and it is not necessary to select geomagnetic detection means at the time of manufacturing, the effect of reducing the manufacturing cost of the azimuth measuring device can be obtained as compared with the related art. .
[0201]
Furthermore, according to the azimuth angle measuring device according to claims 7 to 10 of the present invention, the length and center coordinates of each principal axis of the elliptical surface are statistically calculated so that the distance between each measurement point and the elliptical surface is minimized. Therefore, even if a measurement error is included in the three-axis output data, the length and center coordinates of each main axis of the ellipsoid can be calculated relatively accurately. Therefore, the effect that the sensitivity or the offset of the terrestrial magnetism detecting means can be more accurately corrected can be obtained.
[0202]
Further, according to the azimuth angle measuring apparatus according to claim 8 of the present invention, the length and center coordinates of each principal axis of the elliptical surface are calculated by solving the error summation expression by a multidimensional optimization method. The length and center coordinates of each main axis can be calculated more accurately. Therefore, an effect is obtained that the sensitivity or offset of the geomagnetism detecting means can be more accurately corrected.
[0203]
Furthermore, according to the azimuth angle measuring apparatus according to claim 9 of the present invention, the length of each principal axis of the ellipsoid is calculated by solving a simultaneous linear equation without using a multidimensional optimization method. A convergence solution can be obtained faster than the azimuth measuring device described in Item 8. Therefore, the effect that the length and the center coordinates of each principal axis of the elliptical surface can be calculated relatively quickly can be obtained.
[0204]
Further, according to the azimuth angle measuring apparatus according to claim 10 of the present invention, the length and center of each principal axis of the elliptical surface are obtained by iterative calculation of the first analysis process and the second analysis process without using the multidimensional optimal method. Since the coordinates are calculated, a convergence solution can be obtained earlier than in the azimuth angle measuring device according to the ninth aspect. Therefore, the effect that the length and the center coordinates of each principal axis of the elliptical surface can be calculated relatively quickly can be obtained.
[0205]
Furthermore, according to the azimuth angle measuring device according to claim 11 of the present invention, when the azimuth angle measuring device is moved / rotated only on a plane perpendicular to any one of the three axes of the geomagnetic detection means. However, the effect that the sensitivity or offset of the terrestrial magnetism detection means can be corrected for the remaining two axes is obtained.
Furthermore, according to the azimuth angle measuring device according to claim 13 of the present invention, when the orientation of the azimuth angle measuring device is stationary or has changed only slightly, the length of each principal axis of the elliptical surface and It is possible to prevent the center coordinates from being calculated with a large error, to improve the length of each principal axis of the ellipsoid and the calculation accuracy of the center coordinates, and to keep the sensitivity and offset calibration accuracy high. The effect that it can be obtained is also obtained.
[0206]
Further, according to the azimuth angle measuring apparatus according to claim 14 of the present invention, when the detected output of terrestrial magnetism includes a large error due to noise or the like, or particularly, the orientation of the two-axis terrestrial magnetism detecting means is a predetermined In the case of a change outside the range, an effect can be obtained that an incorrect sensitivity or offset value can be calculated and inappropriate output correction can be prevented.
[0207]
Further, according to the azimuth angle measuring device according to the fifteenth aspect of the present invention, it is possible to obtain the effect that the user can automatically correct each axis output by performing the azimuth angle measurement. .
Further, according to the azimuth angle measuring device according to claim 16 or 17 of the present invention, there is also obtained an effect that the user can grasp the goodness of the correction by the output correction means by referring to the goodness information. .
[0208]
Further, according to the azimuth angle measuring apparatus according to the seventeenth aspect of the present invention, it is possible to obtain goodness (for example, goodness, goodness, goodness, etc.) corresponding to each section. The effect that the goodness of the correction due to is more easily grasped is also obtained.
Further, according to the azimuth angle measuring apparatus according to claim 18 of the present invention, when a static external environmental magnetic field exists or when the geomagnetism is shielded, the geomagnetism is correctly detected. There is also obtained an advantage that it is possible to prevent azimuth angle measurement from being performed in spite of the absence.
[0209]
Furthermore, according to the azimuth angle measuring device according to claim 19 or 20 of the present invention, there is an effect that the user can grasp the reliability of the azimuth angle measurement result by referring to the reliability information.
Furthermore, according to the azimuth angle measuring apparatus according to the twentieth aspect of the present invention, it is possible to obtain the reliability (for example, the reliability such as excellent, good, or acceptable) corresponding to each section. The effect that the reliability of the result can be more easily grasped is also obtained.
[0210]
On the other hand, according to the calibration program according to claim 21 of the present invention, the same effect as that of the azimuth measuring device according to claim 5 can be obtained.
Further, according to the calibration program according to claim 22 of the present invention, an effect equivalent to that of the azimuth measuring device according to claim 6 can be obtained.
On the other hand, according to the calibration method of the twenty-third aspect of the present invention, an effect equivalent to that of the azimuth angle measuring apparatus of the fifth aspect is obtained.
Further, according to the calibration method according to claim 24 of the present invention, the same effect as the azimuth angle measuring device according to claim 6 can be obtained.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a perspective configuration of a portable device 201 to which the present invention is applied.
FIG. 2 is a block diagram showing a schematic configuration of an azimuth angle measuring device according to the present invention.
FIG. 3 is a diagram illustrating the concept of a calibration method.
FIG. 4 is a diagram showing an output waveform of a magnetic sensor when the azimuth measuring device is rotated at a constant angular velocity around the z-axis.
FIG. 5 is a flowchart illustrating a calibration method of a conventional azimuth measuring device.
[Explanation of symbols]
201 Mobile devices
202 Display
203 antenna
11 3-axis magnetic sensor
HEx x-axis Hall element
HEy y-axis Hall element
HEz z-axis Hall element
12 Magnetic sensor drive power supply
13 Chopper
14 Differential input amplifier
15 A / D converter
16 Correction calculation unit
17 Azimuth angle calculation unit
18 Offset / sensitivity correction coefficient calculation unit
19a Offset information storage unit
19b Sensitivity correction information storage unit

Claims (24)

Detecting means of three or more axes for detecting a vector physical quantity,
Detection output acquisition means for repeatedly acquiring a three-axis output when the orientation of the detection means changes in a three-dimensional space a predetermined number of times or more,
On the three-dimensional coordinates having the three-axis output as a component, each principal axis defines an elliptical surface parallel to each coordinate axis of the three-dimensional coordinates, and based on a three-axis output data group repeatedly obtained by the detection output obtaining means, Ellipsoidal analysis means for calculating the length of each principal axis of the ellipsoidal surface,
A measuring device comprising: an output correcting unit configured to correct a three-axis output of the detecting unit based on a length of each principal axis of the elliptical surface calculated by the elliptic surface analyzing unit. Detecting means of three or more axes for detecting a vector physical quantity,
Detection output acquisition means for repeatedly acquiring a three-axis output when the orientation of the detection means changes in a three-dimensional space a predetermined number of times or more,
On the three-dimensional coordinates having the three-axis output as a component, each principal axis defines an elliptical surface parallel to each coordinate axis of the three-dimensional coordinates. Ellipsoidal analysis means for calculating the center coordinates of the ellipsoidal surface,
A measuring device comprising: an output correction unit configured to correct a three-axis output of the detection unit based on the center coordinates calculated by the ellipsoid analysis unit. Detecting means of two or more axes for detecting a vector physical quantity,
Detection output acquisition means for repeatedly acquiring a two-axis output when the orientation of the detection means changes while maintaining it on a predetermined plane for a predetermined number of times,
On a two-dimensional coordinate having the two-axis output as a component, each principal axis defines an ellipse parallel to each coordinate axis of the two-dimensional coordinate, and based on a two-axis output data group repeatedly obtained by the detection output obtaining means, Ellipse analysis means for calculating the length of each principal axis of the ellipse,
A measuring device comprising: an output correction unit configured to correct a biaxial output of the detection unit based on a length of each principal axis of the ellipse calculated by the ellipse analysis unit. Detecting means of two or more axes for detecting a vector physical quantity,
Detection output acquisition means for repeatedly acquiring a two-axis output when the orientation of the detection means changes while maintaining it on a predetermined plane for a predetermined number of times,
On a two-dimensional coordinate having the two-axis output as a component, each principal axis defines an ellipse parallel to each coordinate axis of the two-dimensional coordinate, and based on a two-axis output data group repeatedly obtained by the detection output obtaining means, Ellipse analysis means for calculating the center coordinates of the ellipse,
A measuring device comprising: an output correcting unit configured to correct a biaxial output of the detecting unit based on the center coordinates calculated by the elliptic analyzing unit. Three or more axes of geomagnetism detecting means for detecting geomagnetism;
Detection output acquisition means for repeatedly acquiring a three-axis output when the orientation of the geomagnetic detection means changes in a three-dimensional space a predetermined number of times or more,
On the three-dimensional coordinates having the three-axis output as a component, each principal axis defines an elliptical surface parallel to each coordinate axis of the three-dimensional coordinates, and based on a three-axis output data group repeatedly obtained by the detection output obtaining means, Elliptical surface analysis means for calculating the length and the center coordinates of each principal axis of the elliptical surface,
An azimuth angle measuring apparatus, comprising: an output correction unit that corrects a three-axis output of the geomagnetic detection unit based on a length and a center coordinate of each principal axis of the ellipsoid calculated by the ellipsoid analysis unit. Two or more axes of geomagnetism detecting means for detecting geomagnetism;
A detection output acquisition unit that repeatedly acquires a biaxial output when the orientation of the geomagnetism detection unit changes while maintaining it on a predetermined plane a predetermined number of times or more,
On a two-dimensional coordinate having the two-axis output as a component, each principal axis defines an ellipse parallel to each coordinate axis of the two-dimensional coordinate, and based on a two-axis output data group repeatedly obtained by the detection output obtaining means, Ellipse analysis means for calculating the length and center coordinates of each principal axis of the ellipse,
An azimuth angle measuring device comprising: an output correcting unit that corrects a biaxial output of the geomagnetic detecting unit based on a length and a center coordinate of each principal axis of the ellipse calculated by the elliptic analyzing unit. In any one of claims 5 and 6,
The ellipsoidal surface analysis means arranges the three-axis output data group repeatedly acquired by the detection output acquisition means on the three-dimensional coordinates, and minimizes the distance between the arranged measurement points and the ellipsoidal surface. The azimuth angle measuring device is characterized in that the length and the center coordinates of each principal axis of the elliptical surface are calculated by a statistical method. In claim 7,
The ellipsoidal analysis means is a multidimensional optimization method for obtaining a convergence solution as an optimal solution by iterative calculation by giving an initial value, and for all the measurement points, a value corresponding to a distance between the measurement point and the ellipse is obtained. An azimuth angle measuring apparatus, wherein an error summation calculation formula for calculating a sum is solved to calculate a length and a center coordinate of each principal axis of the elliptical surface. In claim 7,
The ellipsoidal analysis means is a multidimensional optimization method that obtains a convergence solution as an optimal solution by iterative calculation by giving an initial value, and calculates a value corresponding to a distance between the measurement point and the ellipsoid for all the measurement points. A first analysis process for solving a total error calculation equation for calculating a sum and calculating center coordinates of the elliptical surface;
Each principal axis of the elliptical surface is calculated by an error total partial differential operation expression obtained by partially differentiating the error summation expression with a variable corresponding to the length of each principal axis of the elliptical surface based on the value calculated in the first analysis process. A second analysis process for calculating the length of
An azimuth angle measuring apparatus characterized by performing a third analysis process in which the first analysis process and the second analysis process are repeated until the value calculated in the second analysis process converges. In claim 7,
The ellipsoidal plane analyzing means calculates an error summation expression for calculating the sum of values corresponding to the distances between the measurement points and the ellipsoidal plane for all the measurement points by partial differentiation with a variable corresponding to the center coordinates of the elliptical plane. A first analysis process of giving the length of each principal axis of the elliptical surface as an initial value to the first error sum partial differential operation expression, and calculating the center coordinates of the ellipsoid by the first error sum partial differential operation expression When,
On the basis of the value calculated in the first analysis process, a second error sum partial differential operation equation obtained by partially differentiating the error sum operation equation with a variable corresponding to the length of each principal axis of the ellipsoidal surface, A second analysis process for calculating the length of each spindle,
An azimuth angle measuring device, wherein a third analysis process of repeatedly performing the first analysis process and the second analysis process is performed until the value calculated in the second analysis process converges. In any one of claims 5 to 10,
The elliptic surface analysis means may specify the three-axis output other than the three-axis output except for the one with the smallest degree of change if the degree of change is equal to or less than a predetermined value. An ellipse in which each main axis is parallel to each coordinate axis of the two-dimensional coordinates is defined on the two-dimensional coordinates having the two-axis output as a component, and the specific two-axis output is included in the three-axis output data group repeatedly obtained by the detection output obtaining means. An azimuth measuring apparatus characterized in that the length and the center coordinates of each of the principal axes of the ellipse are calculated based on the above. In any one of claims 5 to 11,
The output correction unit is configured to correct the sensitivity and offset for the three-axis output of the geomagnetic detection unit based on the length and center coordinates of each principal axis calculated by the ellipsoid analysis unit. Azimuth angle measuring device. In any one of claims 5 to 12,
The ellipsoid analysis means,
A first difference calculating unit that repeatedly obtains each axis output by the detection output obtaining unit a predetermined number of times and calculates a difference between a maximum value and a minimum value of each axis output;
A first difference determination unit that determines whether the difference calculated by the first difference calculation unit is equal to or greater than a predetermined value,
When the difference calculated by the first difference calculating means is equal to or more than a predetermined value, each axis output repeatedly obtained by the detection output obtaining means a predetermined number of times is set as a target of the ellipsoidal analysis. Azimuth angle measurement device. In any one of claims 5 to 12,
The output correction means,
The length of each principal axis of the ellipsoid calculated by the ellipsoid analysis means and the variation of the length of each principal axis of the ellipse previously calculated by the ellipse analysis means or the ellipse calculated by the ellipse analysis means The apparatus further includes a variation calculation unit configured to calculate a variation in center coordinates of the ellipsoid previously calculated by the center coordinates of the surface and the ellipsoid analysis unit,
An azimuth angle measuring apparatus, wherein the length and the center coordinates of each principal axis of the ellipsoid calculated by the ellipsoid analysis unit based on the calculation result of the variation calculation unit are discarded. In any one of claims 5 to 14,
During the execution of the azimuth angle measurement, the calculation and output correction of the length and center coordinates of each main axis of the ellipsoid are performed in the background using each axis output acquired for the azimuth angle measurement, and the correction of each axis output Azimuth angle measuring device characterized by performing the above at any time. In any one of claims 5 to 15,
The length of each principal axis of the ellipsoid calculated by the ellipsoid analysis means and the variation of the length of each principal axis of the ellipse previously calculated by the ellipse analysis means or the ellipse calculated by the ellipse analysis means Second variation calculation means for calculating the variation of the center coordinates of the surface and the center coordinates of the ellipsoid previously calculated by the ellipsoid analysis means,
An azimuth angle measuring apparatus, comprising: goodness information creating means for creating goodness information on goodness of correction by the output correction means based on a calculation result by the second variation calculation means. In claim 16,
The goodness information creating means classifies the degree of goodness of correction by the output correction means into a plurality of categories, and classifies the goodness information into one of the categories according to the degree of variation calculated by the second variation calculating means, An azimuth angle measuring device for creating goodness information indicating a goodness degree corresponding to the classification. In any one of claims 5 to 17,
The output correction means,
Axis length calculation means for calculating the length of each axis of the elliptical surface,
An axis length determination unit that determines whether the length of each axis of the elliptical surface calculated by the axis length calculation unit is outside a predetermined range,
The azimuth angle measuring device is characterized in that when the length of each axis of the elliptical surface calculated by the axis length calculating means is outside a predetermined range, the output data is discarded. In any one of claims 5 to 17,
Second axis length calculation means for calculating the length of each axis of the elliptical surface;
And a reliability information creating means for creating reliability information on the reliability of the azimuth measurement result based on the length of each axis of the elliptical surface calculated by the second axis length calculating means. Azimuth angle measurement device. In claim 19,
The reliability information creating means divides the reliability of the azimuth angle measurement result into a plurality of pieces, and compares the length of each axis of the ellipsoid calculated by the second axis length calculation means with a plurality of thresholds. An azimuth angle measuring apparatus, wherein the azimuth angle is classified into one of the sections and reliability information indicating the reliability corresponding to the section is created. A program for causing an available computer to execute geomagnetic detection means having three or more axes for detecting geomagnetism,
Detection output acquisition means for repeatedly acquiring a three-axis output when the orientation of the geomagnetism detection means changes in a three-dimensional space a predetermined number of times or more,
On the three-dimensional coordinates having the three-axis output as a component, each principal axis defines an elliptical surface parallel to each coordinate axis of the three-dimensional coordinates, and based on a three-axis output data group repeatedly obtained by the detection output obtaining means, An ellipsoidal analysis means for calculating the length and center coordinates of each principal axis of the ellipsoidal surface, and the three-dimensional geomagnetic detection means based on the lengths and center coordinates of each main axis of the ellipsoidal surface calculated by the ellipsoidal analysis means. A calibration program, which is a program for causing the computer to execute processing realized as output correction means for correcting an axis output. A program for causing an available computer to execute two or more axes of terrestrial magnetism detecting means for detecting terrestrial magnetism,
Detection output acquisition means for repeatedly acquiring a biaxial output when the orientation of the geomagnetism detection means changes while maintaining it on a predetermined plane for a predetermined number of times or more,
On a two-dimensional coordinate having the two-axis output as a component, each principal axis defines an ellipse parallel to each coordinate axis of the two-dimensional coordinate, and based on a two-axis output data group repeatedly obtained by the detection output obtaining means, Ellipse analysis means for calculating the length and center coordinates of each main axis of the ellipse, and correcting the two-axis output of the geomagnetic detection means based on the length and center coordinates of each main axis of the ellipse calculated by the ellipse analysis means A calibration program, which is a program for causing the computer to execute processing realized as output correction means. Changing the detection directions of the three axes in the geomagnetic measurement in a three-dimensional space;
Obtaining a three-axis output of geomagnetism measurement when the detection direction changes;
Determining whether the acquisition of the three-axis output is a predetermined number or more;
On the three-dimensional coordinates having the three-axis output as a component, an elliptical surface in which each principal axis is parallel to each coordinate axis of the three-dimensional coordinates is determined. Calculating the length and center coordinates of each main axis of
Correcting the three-axis output based on the calculated lengths and center coordinates of the principal axes of the elliptical surface. Changing the detection directions of the two axes in the geomagnetic measurement while keeping them on a predetermined plane;
Obtaining a two-axis output of geomagnetic measurement when the detection direction changes;
Determining whether the acquisition of the two-axis output is equal to or more than a predetermined number of times;
On the two-dimensional coordinates having the two-axis output as a component, each principal axis defines an ellipse parallel to each coordinate axis of the two-dimensional coordinate, and based on the two-axis output data group acquired at least the predetermined number of times, each of the ellipses is determined. Calculating the length and center coordinates of the main shaft;
Correcting the biaxial output based on the calculated length and center coordinates of each principal axis of the ellipse.

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