JP2004150852A

JP2004150852A - Satellite signal receiver

Info

Publication number: JP2004150852A
Application number: JP2002313912A
Authority: JP
Inventors: Kenichi Koike; 謙一小池
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2002-10-29
Filing date: 2002-10-29
Publication date: 2004-05-27

Abstract

<P>PROBLEM TO BE SOLVED: To provide a satellite signal receiver for calculating an optimum position without accumulating an error in speed. <P>SOLUTION: A signal analysis section 12 acquires the state of a signal, the propagation distance of the signal, a Doppler shift frequency, and a navigation message. A position measuring section 13 uses them for calculating the position, speed, and velocity azimuth of the satellite signal receiver and stores them in a positioning result storage section 18. An estimation position calculation section 14 obtains an estimation position according to a position calculated by a correction position calculation section 17 at the last time and a velocity vector obtained by the previous speed and velocity azimuth stored in the positioning result storage section 18. A calculation position reliability calculation section 15 calculates reliability for a position calculated by the positioning section 13. An estimation position reliability calculation section 16 calculates reliability for the estimated position. The correction position calculation section 17 obtains weight from the reliability for the calculated position and that for the estimated position for calculating a correction position. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、地球の上空を周回している複数個の航法衛星から地球上に放射される電波を受信することにより、利用者の現在位置を算出する衛星信号受信機に関する。
【０００２】
【従来の技術】
従来の衛星信号受信機としては、次に記載されているものが知られている。従来の衛星信号受信機の構成を示す図１１において、従来の衛星信号受信機は、複数のＧＰＳ衛星からの信号を受信するアンテナ部９１と、アンテナ部９１で受信した信号によって測位演算を行い観測位置や移動速度、移動方向、位置誤差範囲（以下、ＵＥＲＥと記す）、時刻等を算出する測位演算部９２と、測位演算部９２で演算した位置データを記憶する測位結果記憶部９３と、測位結果記憶部９３に記憶された位置データを観測者に知らせる表示通知部９４と、測位補正部９５とを備えている。
【０００３】
測位補正部９５は、測位演算部９２で算出された速度と方位を参照して自位置を相対的に推測する推測位置算出部９６と、推測位置算出部９６によって求められた推測位置が自位置として適切かどうか判定する推測位置妥当性判定部９７と、推測位置妥当性判定部９７によって推測位置が自位置として適切でないと判断された場合、推測位置算出部９６で算出された推測位置と測位演算部９２で算出された位置との２点間を結ぶ直線上に自位置として最も適当な位置を決定する推測位置補正部９８とで構成されている。
【０００４】
次に図１１を用いて従来の衛星信号受信機の動作について説明する。一般的な衛星信号受信機であるＧＰＳ受信機の動作については多くの書籍や特許公報に記載されているので省略し、ここでは特に測位補正部９５の動作について詳細に説明する。
【０００５】
まず推測位置算出部９６にて、測位結果記憶部９３で記憶していた前回の位置に測位演算部９２が算出する速度と方位をベクトル加算し相対的な位置（以下推測位置と言う）を求める。次に推測位置妥当性判定部９７にて測位演算部９２で算出した位置（以下算出位置と言う）と推測位置との距離差を求める。
【０００６】
この距離差とＵＥＲＥとを比較して、距離差がＵＥＲＥよりも大きい場合は、推測位置補正部９８にて算出位置と推測位置とを結んだ直線とＵＥＲＥの限界線の交点を求め補正位置とし、測位結果記憶部９３に補正位置として記憶する。逆に距離差がＵＥＲＥよりも小さい場合は、算出位置の信頼度に応じて算出位置と推測位置を結んだ直線上に補正位置を決定する。
【０００７】
その際の算出位置の信頼度は、算出位置の軌跡が連なっている時は信頼度が上がり、受信可能衛星の切り替わり等で算出位置が急に不連続に変化した時は信頼度が下がるように設定される。求められた補正位置を表示通知部９４により、利用者に通知する（例えば特許文献１参照）。
【０００８】
【特許文献１】
特開２０００−２７５９号公報（第３−４頁、図１）
【０００９】
【発明が解決しようとする課題】
しかし、このような従来の衛星信号受信機では、推測位置が適当であると判断されると、推測位置をそのまま出力位置としているが、推測位置が適当であると判断されつづけると、推測位置はあくまでも相対的な位置であるため、速度の誤差が累積誤差として蓄積されてしまうという問題があった。
【００１０】
本発明は、このような従来の問題を解決するためになされたものであり、速度の誤差が累積されることなく最適な位置を算出することができる衛星信号受信機を提供することを目的とする。
【００１１】
【課題を解決するための手段】
本発明の衛星信号受信機は、航法衛星からの信号を受信するアンテナと、伝搬距離とドップラーシフト周波数と航法メッセージとを取得するためにアンテナで受信した信号を解析する信号解析手段と、信号解析手段で取得した伝搬距離とドップラーシフト周波数と航法メッセージとから位置と速度と速度方位とを算出する測位手段と、現在の推測位置を算出する推測位置算出手段と、測位手段で算出した位置を算出位置とし、算出位置の信頼度を算出する算出位置信頼度算出手段と、推測位置算出手段で算出した推測位置の信頼度を算出する推測位置信頼度算出手段と、算出位置の信頼度と推測位置の信頼度とによって算出位置と推測位置とから補正位置と補正位置の信頼度とを算出する補正位置算出手段とを備え、推測位置算出手段は、測位手段で算出した速度と速度方位とを記憶する測位結果記憶手段を備え、測位結果記憶手段で記憶した前回の速度と速度方位、並びに、自律速度算出手段が算出した速度と速度方位と、補正位置算出手段が算出した前回の補正位置とから現在の推測位置を算出する構成を有するものである。
【００１２】
この構成により、測位毎に算出位置信頼度算出手段で算出した算出位置の信頼度と推測位置信頼度算出手段で算出した推測位置の信頼度とから最適な位置を算出することによって速度の誤差が累積誤差として蓄積されることなく測位精度の向上を図ることができる。
【００１３】
本発明の衛星信号受信機は、航法衛星からの信号を受信するアンテナと、伝搬距離とドップラーシフト周波数と航法メッセージとを取得するためにアンテナで受信した信号を解析する信号解析手段と、信号解析手段で取得した伝搬距離とドップラーシフト周波数と航法メッセージとから位置と速度と速度方位とを算出する測位手段と、現在の推測位置を算出する推測位置算出手段と、測位手段で算出した位置を算出位置とし、算出位置の信頼度を算出する算出位置信頼度算出手段と、推測位置算出手段で算出した推測位置の信頼度を算出する推測位置信頼度算出手段と、算出位置の信頼度と推測位置の信頼度とによって算出位置と推測位置とから補正位置と補正位置の信頼度とを算出する補正位置算出手段とを備え、推測位置算出手段は、自律センサによって速度と速度方位とを算出する自律速度算出手段を備え、自律速度算出手段が算出した速度と速度方位と、補正位置算出手段が算出した前回の補正位置とから現在の推測位置を算出する構成を有するものである。
【００１４】
この構成により、測位毎に算出位置信頼度算出手段で算出した算出位置の信頼度と推測位置信頼度算出手段で算出した推測位置の信頼度とから最適な位置を算出することによって速度の誤差が累積誤差として蓄積されることなく測位精度の向上を図ることができる。
【００１５】
また、本発明の衛星信号受信機は、算出位置信頼度算出手段が、航法メッセージと信号解析手段に入力された航法衛星からの信号の状態とにより算出位置の誤差半径を算出する算出位置誤差半径算出手段を備え、算出位置誤差半径算出手段が算出した誤差半径に基づいて算出位置の信頼度を算出する構成を有するものである。
【００１６】
この構成により、算出位置誤差半径算出手段で算出した算出位置の誤差半径によって算出位置の信頼度を算出することによって、速度の誤差が累積誤差として蓄積されることなく最適な位置を算出でき、測位精度の向上を図ることができる。
【００１７】
また、本発明の衛星信号受信機は、算出位置信頼度算出手段が、信号解析手段で取得した航法メッセージから算出した航法衛星の位置と算出位置との幾何学的な距離を算出する幾何学的距離算出手段と、信号解析手段で取得した各航法衛星の信号の伝搬距離と幾何学的距離算出手段で算出した幾何学的な距離との距離差を算出する距離差算出手段と、距離差算出手段で算出した距離差の標準偏差を計算する標準偏差算出手段とを備え、標準偏差算出手段で算出した標準偏差により算出位置の信頼度を算出する構成を有するものである。
【００１８】
この構成により、標準偏差算出手段で算出した各衛星の幾何学的距離と伝搬距離との距離差の標準偏差によって算出位置の信頼度を算出することによって、速度の誤差が累積誤差として蓄積されることなく最適な位置を算出でき、測位精度の向上を図ることができる。
【００１９】
また、本発明の衛星信号受信機は、算出位置信頼度算出手段が、測位手段で使用した航法衛星の数を記憶しておく衛星数記憶手段を備え、衛星数記憶手段で記憶した航法衛星数により算出位置の信頼度を変更する構成を有するものである。
【００２０】
この構成により、衛星数記憶手段で記憶している航法衛星の数によって標準偏差算出手段で算出した各衛星の幾何学的距離と伝搬距離との距離差の標準偏差と算出位置の信頼度との関係を変更することによって算出位置の信頼度をより正確に算出することができる。
【００２１】
また、本発明の衛星信号受信機は、算出位置信頼度算出手段が、緯度と経度で示される位置に対応する高度を保持する高度保持手段と、算出位置の緯度と経度に対応する高度を高度保持手段から取得する高度取得手段と、測位手段で算出した算出位置の高度と高度取得手段で取得した高度との差を計算し算出位置の高度誤差を算出する高度誤差算出手段とを備え、高度誤差算出手段が算出した算出位置の高度誤差により算出位置の信頼度を算出する構成を有するものである。
【００２２】
この構成により、高度誤差算出手段で算出した算出位置の高度誤差によって算出位置の信頼度を算出することによって、速度の誤差が累積誤差として蓄積されることなく最適な位置を算出でき、測位精度の向上を図ることができる。
【００２３】
また、本発明の衛星信号受信機は、推測位置信頼度算出手段が、前回の速度の誤差を推定する速度誤差推定手段を備え、速度誤差推定手段で推定した前回の速度誤差と補正位置算出手段で算出した補正位置の信頼度とから推測位置の信頼度を算出する構成を有するものである。
【００２４】
この構成により、速度誤差推定手段で推定した前回の速度誤差と補正位置算出手段で算出した補正位置の信頼度とから推測位置の信頼度を算出することによって、速度の誤差が累積誤差として蓄積されることなく最適な位置を算出でき、測位精度の向上を図ることができる。
【００２５】
また、本発明の衛星信号受信機は、推測位置信頼度算出手段が、測位手段で算出した今回の速度と前回の速度とから速度変化を算出する速度変化算出手段を備え、速度変化算出手段が算出した速度変化に基づいて推測位置の信頼度を算出する構成を有するものである。
【００２６】
この構成により、速度変化算出手段で算出した速度変化によって推測位置の信頼度を算出することによって、速度の誤差が累積誤差として蓄積されることなく最適な位置を算出でき、測位精度の向上を図ることができる。
【００２７】
【発明の実施の形態】
以下、本発明の実施の形態について図面を用いて説明する。
【００２８】
（第１の実施の形態）
図１は、本発明の第１の実施の形態における衛星信号受信機の構成を示すブロック図である。本実施の形態における衛星信号受信機は、航法衛星からの信号を受信するアンテナ１１と、アンテナ１１で受信した信号を解析し伝搬距離とドップラーシフト周波数と航法メッセージとを取得する信号解析部１２と、信号解析部１２で取得した伝搬距離とドップラーシフト周波数と航法メッセージとから位置と速度と速度方位とを算出する測位部１３と、現在の推測位置を算出する推測位置算出部１４と、測位部１３で算出した位置を算出位置とし、算出位置の信頼度を算出する算出位置信頼度算出部１５と、推測位置算出部１４で算出した推測位置の信頼度を算出する推測位置信頼度算出部１６と、算出位置信頼度算出部１５で算出した算出位置の信頼度と推測位置信頼度算出部１６で算出した推測位置の信頼度とによって算出位置と推測位置とから補正位置と補正位置の信頼度とを算出する補正位置算出部１７と、求められた補正位置を表示して利用者に通知する表示通知部１９とを備えている。
【００２９】
推測位置算出部１４は、測位部１３で算出した速度と速度方位とを記憶する測位結果記憶部１８を備えている。
【００３０】
次に、図１と図２を用いて、本発明の第１の実施の形態における衛星信号受信機の動作について説明する。図２は本発明の第１の実施の形態における衛星信号受信機の算出位置と推測位置と補正位置との関係を示した図である。まず、アンテナ１１で所定の個数（例えば４個）の航法衛星からの送信信号を受信する。アンテナ１１で受信した信号は、信号解析部１２で解析を行い、信号の強度、Ｓ／Ｎ比、遮断時間や航法メッセージを取得する際の航法メッセージ信号の各ビットのエッジを安定して検出しているかを表す追尾安定度といった信号の状態と信号の伝搬距離とドップラーシフト周波数と航法メッセージとを取得する。
【００３１】
測位部１３は信号解析部１２で取得した信号の伝搬距離とドップラーシフト周波数と航法メッセージとを用いて衛星信号受信機の位置と速度と速度方位とを算出する。測位部１３で算出した衛星信号受信機の速度と速度方位とを推測位置算出部１４にある測位結果記憶部１８に記憶する。
【００３２】
推測位置算出部１４は、前回に補正位置算出部１７で算出した位置Ｘｎ−１に測位結果記憶部１８に記憶した前回の速度と速度方位とから求められる速度ベクトルＶｎ−１を加算して推測位置Ｙｎを求める。算出位置信頼度算出部１５は測位部１３で算出した位置（以下、算出位置と記す）Ｚｎの信頼度を算出する。
【００３３】
推測位置信頼度算出部１６は推測位置算出部１４で算出した推測位置Ｙｎの信頼度を算出する。補正位置算出部１７は算出位置信頼度算出部１５で算出した算出位置Ｚｎの信頼度と推測位置信頼度算出部１６で算出した推測位置Ｙｎの信頼度とから推測位置Ｙｎへの重みＴｎを求め補正位置Ｘｎを算出する。重みＴｎは予測位置の信頼度が算出位置の信頼度に比べ高ければ小さく、逆に算出位置の信頼度が推測位置の信頼度より高ければ大きくなるように設定する。
【００３４】
このように、本実施の形態によれば、測位毎に算出位置信頼度算出部１５で算出した算出位置の信頼度と推測位置信頼度算出部１６で算出した推測位置の信頼度とから最適な補正位置を算出することによって測位精度の向上を図ることができる。
【００３５】
（第２の実施の形態）
図３は、本発明の第２の実施の形態における衛星信号受信機の構成を示すブロック図である。この衛星信号受信機は、算出位置信頼度算出部１５が、測位部１３で算出した算出位置の誤差半径を算出する算出位置誤差半径算出部２１を備えている。その他の点は、第１の実施の形態と同じであるので、その処理・動作に関して異なる点を中心に図３を用いて説明する。
【００３６】
算出位置誤差半径算出部２１は、算出位置の誤差半径を算出する。その際の誤差半径は、たとえばＧＤＯＰ（ＧｅｏｍｅｔｒｉｃａｌＤｉｌｕｔｉｏｎｏｆＰｒｅｃｉｓｉｏｎ。幾何学的精度劣化度：測位に使う衛星が被測位位置に対し、誤差の少ない配置にあるかどうかの偏差を目安に計算したもの。）と、信号解析部１２で取得した信号の状態と航法メッセージとから見積もった各衛星の伝搬距離の誤差とを利用することによって算出する。
【００３７】
算出位置信頼度算出部１５は、算出位置誤差半径算出部２１で算出した算出位置の誤差半径から算出位置の信頼度を算出する。例えば、算出位置誤差半径算出部２１で算出した算出位置の誤差半径が０ｍのとき、算出位置の信頼度を１として、誤差半径が大きくなるにつれて信頼度の値を減少させ、誤差半径が１００ｍ以上になったら信頼度を０となるようにする。
【００３８】
このように、本実施の形態によれば、算出位置誤差半径算出部２１で算出した算出位置の誤差半径によって算出位置の信頼度を算出することができる。
【００３９】
なお、上記実施の形態では推測位置算出部が測位結果記憶部を有する場合で説明したが、本発明はこの測位結果記憶部を有する場合に限定されることなく、自立速度算出部を有する場合でも同様の効果が得られる。
【００４０】
（第３の実施の形態）
図４は、本発明の第３の実施の形態における衛星信号受信機の構成を示すブロック図である。
【００４１】
この衛星信号受信機は、算出位置信頼度算出部１５が、測位部１３で算出した算出位置と各衛星との幾何学的な距離を算出する幾何学的距離算出部３１と、信号解析部１２で取得した各衛星の信号の伝搬距離と幾何学的距離算出部３１で算出した距離との距離差を算出する距離差算出部３２と、距離差算出部３２で算出した各衛星の幾何学的距離と伝搬距離との距離差の標準偏差を計算する標準偏差算出部３３とを備えている。
【００４２】
その他の点は、第１の実施の形態と同じであるので、その処理・動作に関して異なる点を中心に図４と図５を用いて説明する。図５は、本発明の第３の実施の形態における算出位置と衛星との幾何学的距離と衛星信号の伝搬距離との関係を示した図である。幾何学的距離算出部３１は測位部１３で算出した算出位置と各衛星１、２との幾何学的距離Ａ１、Ａ２を算出する。
【００４３】
距離差算出部３２は信号解析部１２で取得した伝搬距離Ｂ１、Ｂ２とＡ１、Ａ２との差を算出する。算出位置の誤差が小さい場合はＡ１とＢ１との差、Ａ２とＢ２との差はそれぞれ小さい値になり、逆に算出位置の誤差が大きい場合はＡ１とＢ１との差、Ａ２とＢ２との差がそれぞれ大きな値になり、かつそれぞれの値は衛星配置によってばらつく。
【００４４】
そこで、標準偏差算出部３３で各衛星の幾何学的距離と伝搬距離との距離差の標準偏差を計算すると、算出位置の誤差が大きい場合は標準偏差が大きくなり、逆に誤差が小さい場合には標準偏差が小さくなるので、標準偏差算出部３３で算出した標準偏差を用いて算出位置の信頼度を算出することができる。
【００４５】
このように、本実施の形態によれば、標準偏差算出部３３で算出した標準偏差を用いて算出位置の信頼度を算出することができる。
【００４６】
なお、上記実施の形態では推測位置算出部が測位結果記憶部を有する場合で説明したが、本発明はこの測位結果記憶部を有する場合に限定されることなく、自立速度算出部を有する場合でも同様の効果が得られる。
【００４７】
（第４の実施の形態）
図６は、本発明の第４の実施の形態における衛星信号受信機の構成を示すブロック図である。この衛星信号受信機は、算出位置信頼度算出部１５が、測位部１３で使用した衛星数を記憶しておく衛星数記憶部３４を備えている。その他の点は、第３の実施の形態と同じであるので、その処理・動作に関して異なる点を中心に説明する。
【００４８】
図６において、衛星数記憶部３４は、測位部１３で使用した衛星数を記憶しておき、算出位置信頼度算出部１５で算出位置の信頼度を算出するとき、衛星数記憶部３４で記憶している衛星数により標準偏差算出部３３で算出した標準偏差と算出位置の信頼度との関係を変更する。
【００４９】
衛星数によって標準偏差と算出位置の信頼度との関係を変更する理由は、衛星数が増えるにしたがって標準偏差は大きくなる傾向があるため、衛星数を考慮に入れないと、衛星数の少ない場合は算出位置の精度が悪いのにも関わらず信頼度を高くしてしまい、逆に衛星数の大きい場合は算出位置の精度が良いのにも関わらず信頼度を低くしてしまう可能性が出るためである。
【００５０】
このように、本実施の形態によれば、衛星数記憶部３４で記憶した衛星数によって標準偏差と算出位置の信頼度との関係を変更することにより、算出位置の信頼度をより正確に算出することができる。
【００５１】
なお、上記実施の形態では推測位置算出部が測位結果記憶部を有する場合で説明したが、本発明はこの測位結果記憶部を有する場合に限定されることなく、自立速度算出部を有する場合でも同様の効果が得られる。
【００５２】
（第５の実施の形態）
図７は、本発明の第５の実施の形態における衛星信号受信機の構成を示すブロック図である。
【００５３】
この衛星信号受信機は、算出位置信頼度算出部１５が、緯度および経度が示す位置における高度を保持する高度保持部４１と、測位部１３で算出した算出位置の緯度および経度における高度を高度情報保持部４１から取得する高度取得部４２と、測位部１３で算出した算出位置の高度と高度取得部４２で取得した高度との差を計算し算出位置の高度誤差を算出する高度誤差算出部４３とを備えている。その他の点は、第１の実施の形態と同じであるので、その処理・動作に関して異なる点を中心に説明する。
【００５４】
図７において、高度取得部４２は、測位部１３で算出した算出位置の緯度および経度を読み込み、その緯度および経度に対応した位置の高度を高度保持部４１から取得する。高度誤差算出部４３は、高度取得部４２で取得した高度と測位部１３で算出した高度との差を計算し算出位置の高度誤差を算出する。測位部１３で算出した算出位置の高度誤差が大きい場合、算出位置の緯度および経度も誤差が大きい可能性が高いと考えられるため、高度誤差算出部４３で算出した高度誤差を用いて算出位置の信頼度を算出する。
【００５５】
このように、本実施の形態によれば、高度誤差算出部４３で算出した算出位置の高度誤差を用いて、算出位置の信頼度を算出することができる。
【００５６】
なお、上記実施の形態では推測位置算出部が測位結果記憶部を有する場合で説明したが、本発明はこの測位結果記憶部を有する場合に限定されることなく、自立速度算出部を有する場合でも同様の効果が得られる。
【００５７】
（第６の実施の形態）
図８は、本発明の第６の実施の形態における衛星信号受信機の構成を示すブロック図である。この衛星信号受信機は、推測位置信頼度算出部１６が、測位結果記憶部１８で記憶している前回の速度の誤差を推定する速度誤差推定部５１を備え、速度誤差推定部５１で推定した前回の速度誤差と補正位置算出部１７で算出した補正位置の信頼度とから推測位置の信頼度を算出する。その他の点は、第１の実施の形態と同じであるので、その処理・動作に関して異なる点を中心に説明する。
【００５８】
図８において、速度誤差推定部５１は、測位結果記憶部１８で記憶していた前回の速度の誤差を推定する。その際の速度誤差の推定値は、たとえば各衛星のドップラーシフト周波数の推定値を利用して算出しても、速度誤差の平均値を利用してもよい。推測位置信頼度算出部１６は、速度誤差算出部５１で算出した前回の速度誤差と補正位置算出部１７で算出した補正位置の信頼度とから推測位置の信頼度を算出する。
【００５９】
このように、本実施の形態によれば、前回の速度誤差と補正位置の信頼度とから推測位置の信頼度を算出することができる。
【００６０】
なお、上記実施の形態では推測位置算出部が測位結果記憶部を有する場合で説明したが、本発明はこの測位結果記憶部を有する場合に限定されることなく、自立速度算出部を有する場合でも同様の効果が得られる。
【００６１】
（第７の実施の形態）
図９は、本発明の第７の実施の形態における衛星信号受信機の構成を示すブロック図である。この衛星信号受信機は、推測位置信頼度算出部１６が、測位結果記憶部１８で記憶された前回の速度と測位部１３で算出した今回の速度との差を計算し速度変化を算出する速度変化算出部５２を備えている。その他の点は、第１の実施の形態と同じであるので、その処理・動作に関して異なる点を中心に説明する。
【００６２】
図９において、速度変化算出部５２は、測位結果記憶部１８で記憶していた前回の速度と測位部１３で算出した今回の速度とから速度変化を算出する。速度変化が衛星信号受信機を搭載している移動体の運動性能以上であった場合、具体的には、移動体が自動車で、速度変化が時速２５０ｋｍと算出され、その自動車の運動性能である最高速度、例えば１８０ｋｍ以上であった場合、算出した速度の誤差が大きくその結果推測位置の誤差も大きくなっていると判断できることから、速度変化を用いて、推測位置の信頼度を算出する。
【００６３】
このように、本実施の形態によれば、速度変化算出部５２で算出した速度変化を用いて、推測位置の信頼度を算出することができる。
【００６４】
なお、上記実施の形態では推測位置算出部が測位結果記憶部を有する場合で説明したが、本発明はこの測位結果記憶部を有する場合に限定されることなく、自立速度算出部を有する場合でも同様の効果が得られる。
【００６５】
（第８の実施の形態）
図１０は、本発明の第８の実施の形態における衛星信号受信機の構成を示すブロック図である。この衛星信号受信機は、推測位置算出部１４が、測位結果記憶部１８に代って、自律センサによって速度と速度方位を算出する自律速度算出部６１を備えている。その他の点は、第１の実施の形態と同じであるので、その処理・動作に関して異なる点を中心に説明する。
【００６６】
図１０において、推測位置算出部１４は、自律速度算出部６１がジャイロスコープや車速パルス等の自律センサを利用して速度と速度方位とを算出する。
このように、本実施の形態によれば、自律センサで算出された速度と速度方位は、衛星信号受信機で算出された速度と速度方位に比べ精度が良いため、自律速度算出部６１で算出した速度と速度方位を用いて推測位置を算出することにより、推測位置の精度ならびに補正位置の精度を向上させることができる。
【００６７】
【発明の効果】
以上説明したように、本発明は、測位結果記憶手段で記憶した前回の速度と速度方向とあるいは自律速度算出手段が算出した速度と速度方位と補正位置算出手段が算出した前回の補正位置とから現在の推測位置を算出する推測位置算出手段と、測位手段で算出した算出位置の信頼度を算出する算出位置信頼度算出手段と、推測位置算出手段で算出した推測位置の信頼度を算出する推測位置信頼度算出手段と、算出位置の信頼度と推測位置の信頼度とによって算出位置と推測位置とから補正位置と補正位置の信頼度とを算出する補正位置算出手段とを備えたことことにより、測位毎に算出位置信頼度算出手段で算出した算出位置の信頼度と推測位置信頼度算出手段で算出した推測位置の信頼度とから最適な位置を算出することによって速度の誤差が累積誤差として蓄積されることなく測位精度の向上を図ることができるというすぐれた効果を有する衛星信号受信機を提供することができる。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態における衛星信号受信機の構成を示すブロック図
【図２】本発明の第１の実施の形態における衛星信号受信機の算出位置と推測位置と補正位置との関係を示す図
【図３】本発明の第２の実施の形態における衛星信号受信機の構成を示すブロック図
【図４】本発明の第３の実施の形態における衛星信号受信機の動作を示すブロック図
【図５】本発明の第３の実施の形態における衛星信号受信機の算出位置と衛星との幾何学的な距離と衛星信号の伝搬距離との関係を示す図
【図６】本発明の第４の実施の形態における衛星信号受信機の動作を示すブロック図
【図７】本発明の第５の実施の形態における衛星信号受信機の構成を示すブロック図
【図８】本発明の第６の実施の形態における衛星信号受信機の動作を示すブロック図
【図９】本発明の第７の実施の形態における衛星信号受信機の動作を示すブロック図
【図１０】本発明の第８の実施の形態における衛星信号受信機の動作を示すブロック図
【図１１】従来の衛星信号受信機の構成を示すブロック図
【符号の説明】
１１アンテナ
１２信号解析部
１３測位部
１４推測位置算出部
１５算出位置信頼度算出部
１６推測位置信頼度算出部
１７補正位置算出部
１８測位結果記憶部
１９表示通知部
２１算出位置誤差半径算出部
３１幾何学的距離算出部
３２距離差算出部
３３標準偏差算出部
３４衛星数記憶部
４１高度保持部
４２高度取得部
４３高度誤差算出部
５１速度誤差推定部
５２速度変化算出部
６１自律速度算出部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a satellite signal receiver that calculates a current position of a user by receiving radio waves radiated on the earth from a plurality of navigation satellites orbiting the earth.
[0002]
[Prior art]
The following are known as conventional satellite signal receivers. In FIG. 11 showing the configuration of a conventional satellite signal receiver, a conventional satellite signal receiver performs an observation by performing a positioning operation based on an antenna unit 91 that receives signals from a plurality of GPS satellites and a signal received by the antenna unit 91. A positioning operation unit 92 for calculating a position, a moving speed, a moving direction, a position error range (hereinafter, referred to as “UERE”), a time, and the like; a positioning result storage unit 93 for storing position data calculated by the positioning operation unit 92; A display notification unit 94 for notifying the observer of the position data stored in the result storage unit 93 and a positioning correction unit 95 are provided.
[0003]
The positioning correction unit 95 includes an estimated position calculation unit 96 that relatively estimates the own position with reference to the speed and the azimuth calculated by the positioning calculation unit 92, and an estimated position calculated by the estimated position calculation unit 96. The estimated position validity determining unit 97 that determines whether the estimated position is appropriate, and when the estimated position validity determining unit 97 determines that the estimated position is not appropriate as the own position, the estimated position calculated by the estimated position calculating unit 96 and the positioning An estimated position correction unit 98 that determines the most appropriate position as its own position on a straight line connecting two points with the position calculated by the calculation unit 92.
[0004]
Next, the operation of the conventional satellite signal receiver will be described with reference to FIG. The operation of the GPS receiver, which is a general satellite signal receiver, is omitted since it is described in many books and patent publications. In particular, the operation of the positioning correction unit 95 will be described in detail.
[0005]
First, the estimated position calculation unit 96 adds the vector and the speed and orientation calculated by the positioning calculation unit 92 to the previous position stored in the positioning result storage unit 93 to obtain a relative position (hereinafter referred to as an estimated position). . Next, the estimated position validity determination unit 97 obtains a distance difference between the position calculated by the positioning calculation unit 92 (hereinafter referred to as a calculated position) and the estimated position.
[0006]
Comparing this distance difference with the UERE, if the distance difference is larger than the UERE, the estimated position correction unit 98 obtains the intersection of the straight line connecting the calculated position and the estimated position with the limit line of the UURE and sets the intersection as the corrected position. Are stored in the positioning result storage unit 93 as corrected positions. On the other hand, when the distance difference is smaller than the UERE, the correction position is determined on a straight line connecting the calculated position and the estimated position according to the reliability of the calculated position.
[0007]
The reliability of the calculated position at that time is such that when the trajectories of the calculated position are continuous, the reliability increases, and when the calculated position suddenly changes discontinuously due to switching of receivable satellites, the reliability decreases. Is set. The obtained correction position is notified to the user by the display notification unit 94 (for example, see Patent Document 1).
[0008]
[Patent Document 1]
JP-A-2000-2759 (page 3-4, FIG. 1)
[0009]
[Problems to be solved by the invention]
However, in such a conventional satellite signal receiver, when it is determined that the estimated position is appropriate, the estimated position is used as it is as the output position. There is a problem that the speed error is accumulated as a cumulative error because the position is a relative position.
[0010]
The present invention has been made to solve such a conventional problem, and has as its object to provide a satellite signal receiver capable of calculating an optimum position without accumulating speed errors. I do.
[0011]
[Means for Solving the Problems]
The satellite signal receiver of the present invention comprises: an antenna for receiving a signal from a navigation satellite; signal analysis means for analyzing a signal received by the antenna to obtain a propagation distance, a Doppler shift frequency, and a navigation message; Positioning means for calculating the position, speed, and velocity direction from the propagation distance, Doppler shift frequency, and navigation message obtained by the means, estimated position calculating means for calculating the current estimated position, and calculating the position calculated by the positioning means A calculated position reliability calculating means for calculating the reliability of the calculated position, a calculated position reliability calculating means for calculating the reliability of the estimated position calculated by the estimated position calculating means, a reliability of the calculated position and the estimated position Correction position calculating means for calculating a correction position and a reliability of the corrected position from the calculated position and the estimated position based on the reliability of the estimated position. A positioning result storage means for storing the speed and the speed azimuth calculated by the means, the previous speed and the speed azimuth stored by the positioning result storage means, and the speed and the speed azimuth calculated by the autonomous speed calculation means; It has a configuration for calculating the current estimated position from the previous correction position calculated by the calculation means.
[0012]
According to this configuration, the speed error is calculated by calculating the optimum position from the reliability of the calculated position calculated by the calculated position reliability calculation unit and the reliability of the estimated position calculated by the estimated position reliability calculation unit for each positioning. The positioning accuracy can be improved without being accumulated as an accumulated error.
[0013]
The satellite signal receiver of the present invention comprises: an antenna for receiving a signal from a navigation satellite; signal analysis means for analyzing a signal received by the antenna to obtain a propagation distance, a Doppler shift frequency, and a navigation message; Positioning means for calculating the position, speed, and velocity direction from the propagation distance, Doppler shift frequency, and navigation message obtained by the means, estimated position calculating means for calculating the current estimated position, and calculating the position calculated by the positioning means A calculated position reliability calculating means for calculating the reliability of the calculated position, a calculated position reliability calculating means for calculating the reliability of the estimated position calculated by the estimated position calculating means, a reliability of the calculated position and the estimated position Correction position calculating means for calculating the correction position and the reliability of the corrected position from the calculated position and the estimated position according to the reliability of the estimated position. An autonomous speed calculating means for calculating a speed and a speed azimuth by a sensor; and calculating a current estimated position from the speed and the speed azimuth calculated by the autonomous speed calculating means and a previous correction position calculated by the correction position calculating means. It has a configuration.
[0014]
According to this configuration, the speed error is calculated by calculating the optimum position from the reliability of the calculated position calculated by the calculated position reliability calculation unit and the reliability of the estimated position calculated by the estimated position reliability calculation unit for each positioning. The positioning accuracy can be improved without being accumulated as an accumulated error.
[0015]
Further, in the satellite signal receiver of the present invention, the calculated position reliability calculating means calculates the calculated position error radius based on the navigation message and the state of the signal from the navigation satellite input to the signal analyzing means. A calculating means for calculating the reliability of the calculated position based on the error radius calculated by the calculated position error radius calculating means.
[0016]
According to this configuration, by calculating the reliability of the calculated position based on the calculated position error radius calculated by the calculated position error radius calculating unit, the optimum position can be calculated without accumulating the speed error as a cumulative error. Accuracy can be improved.
[0017]
Further, in the satellite signal receiver of the present invention, the calculated position reliability calculating means calculates a geometric distance between the position of the navigation satellite calculated from the navigation message acquired by the signal analyzing means and the calculated position. Distance calculating means; distance difference calculating means for calculating a distance difference between a propagation distance of each navigation satellite signal acquired by the signal analyzing means and a geometric distance calculated by the geometric distance calculating means; Standard deviation calculating means for calculating the standard deviation of the distance difference calculated by the means, and the reliability of the calculated position is calculated based on the standard deviation calculated by the standard deviation calculating means.
[0018]
With this configuration, the reliability of the calculated position is calculated based on the standard deviation of the distance difference between the geometric distance and the propagation distance of each satellite calculated by the standard deviation calculation means, and the speed error is accumulated as a cumulative error. It is possible to calculate the optimum position without the need to improve the positioning accuracy.
[0019]
Further, in the satellite signal receiver of the present invention, the calculated position reliability calculating means includes satellite number storing means for storing the number of navigation satellites used in the positioning means, and the navigation satellite number stored in the satellite number storing means. To change the reliability of the calculated position.
[0020]
With this configuration, the standard deviation of the distance difference between the geometric distance and the propagation distance of each satellite calculated by the standard deviation calculating means based on the number of navigation satellites stored in the satellite number storing means and the reliability of the calculated position are calculated. By changing the relationship, the reliability of the calculated position can be calculated more accurately.
[0021]
Further, in the satellite signal receiver of the present invention, the calculated position reliability calculating means includes an altitude holding means for holding an altitude corresponding to the position indicated by the latitude and the longitude, and an altitude corresponding to the latitude and the longitude of the calculated position. Altitude obtaining means for obtaining from the holding means, and altitude error calculating means for calculating a difference between the altitude of the calculated position calculated by the positioning means and the altitude obtained by the altitude obtaining means and calculating an altitude error of the calculated position, It has a configuration for calculating the reliability of the calculated position based on the altitude error of the calculated position calculated by the error calculating means.
[0022]
With this configuration, by calculating the reliability of the calculated position based on the altitude error of the calculated position calculated by the altitude error calculating means, the optimum position can be calculated without accumulating the speed error as a cumulative error, and the positioning accuracy can be reduced. Improvement can be achieved.
[0023]
Further, in the satellite signal receiver of the present invention, the estimated position reliability calculating means includes speed error estimating means for estimating a previous speed error, and the previous speed error estimated by the speed error estimating means and the corrected position calculating means are provided. And the reliability of the estimated position is calculated from the reliability of the corrected position calculated in (1).
[0024]
According to this configuration, the reliability of the estimated position is calculated from the previous speed error estimated by the speed error estimating means and the reliability of the corrected position calculated by the corrected position calculating means, so that the speed error is accumulated as an accumulated error. It is possible to calculate the optimum position without the need to improve the positioning accuracy.
[0025]
Further, in the satellite signal receiver of the present invention, the estimated position reliability calculating means includes speed change calculating means for calculating a speed change from the current speed calculated by the positioning means and the previous speed, and the speed change calculating means is provided. It has a configuration for calculating the reliability of the estimated position based on the calculated speed change.
[0026]
According to this configuration, by calculating the reliability of the estimated position based on the speed change calculated by the speed change calculating unit, the optimum position can be calculated without accumulating the speed error as a cumulative error, and the positioning accuracy is improved. be able to.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0028]
(First Embodiment)
FIG. 1 is a block diagram showing a configuration of the satellite signal receiver according to the first embodiment of the present invention. The satellite signal receiver according to the present embodiment includes an antenna 11 that receives a signal from a navigation satellite, a signal analysis unit 12 that analyzes a signal received by the antenna 11 and obtains a propagation distance, a Doppler shift frequency, and a navigation message. A positioning unit 13 for calculating a position, a speed, and a speed azimuth from the propagation distance, the Doppler shift frequency, and the navigation message acquired by the signal analysis unit 12, an estimated position calculation unit 14 for calculating a current estimated position, and a positioning unit. The calculated position is used as the calculated position, and the calculated position reliability calculator 15 calculates the reliability of the calculated position. The estimated position reliability calculator 16 calculates the reliability of the estimated position calculated by the estimated position calculator 14. And the reliability of the calculated position calculated by the calculated position reliability calculation unit 15 and the reliability of the estimated position calculated by the estimated position reliability calculation unit 16 to estimate the calculated position. It includes a correction position calculating section 17 that calculates the reliability of the correction position and the correction position and a location, and a display notification unit 19 to notify the user by displaying the corrected position obtained.
[0029]
The estimated position calculation unit 14 includes a positioning result storage unit 18 that stores the speed and the speed azimuth calculated by the positioning unit 13.
[0030]
Next, the operation of the satellite signal receiver according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a diagram illustrating a relationship between the calculated position, the estimated position, and the corrected position of the satellite signal receiver according to the first embodiment of the present invention. First, the antenna 11 receives transmission signals from a predetermined number (for example, four) of navigation satellites. The signal received by the antenna 11 is analyzed by the signal analysis unit 12 to stably detect the signal strength, the S / N ratio, the cutoff time, and the edge of each bit of the navigation message signal when acquiring the navigation message. Of the signal, such as tracking stability, which indicates whether the signal has been transmitted, the propagation distance of the signal, the Doppler shift frequency, and the navigation message.
[0031]
The positioning unit 13 calculates the position, speed, and speed direction of the satellite signal receiver using the signal propagation distance, the Doppler shift frequency, and the navigation message acquired by the signal analysis unit 12. The speed and direction of the satellite signal receiver calculated by the positioning unit 13 are stored in the positioning result storage unit 18 in the estimated position calculation unit 14.
[0032]
The estimated position calculation unit 14 estimates by adding the speed vector Vn-1 obtained from the previous speed and the speed azimuth stored in the positioning result storage unit 18 to the position Xn-1 calculated by the correction position calculation unit 17 last time. Find the position Yn. The calculated position reliability calculating unit 15 calculates the reliability of the position (hereinafter, referred to as a calculated position) Zn calculated by the positioning unit 13.
[0033]
The estimated position reliability calculator 16 calculates the reliability of the estimated position Yn calculated by the estimated position calculator 14. The correction position calculation unit 17 obtains a weight Tn for the estimated position Yn from the reliability of the calculated position Zn calculated by the calculated position reliability calculation unit 15 and the reliability of the estimated position Yn calculated by the estimated position reliability calculation unit 16. The correction position Xn is calculated. The weight Tn is set to be smaller when the reliability of the predicted position is higher than the reliability of the calculated position, and to be larger when the reliability of the calculated position is higher than the reliability of the estimated position.
[0034]
As described above, according to the present embodiment, the optimum position reliability is calculated from the reliability of the calculated position calculated by the calculated position reliability calculation unit 15 and the reliability of the estimated position calculated by the estimated position reliability calculation unit 16 for each positioning. By calculating the corrected position, the positioning accuracy can be improved.
[0035]
(Second embodiment)
FIG. 3 is a block diagram illustrating a configuration of a satellite signal receiver according to the second embodiment of the present invention. The satellite signal receiver includes a calculated position error radius calculator 21 in which the calculated position reliability calculator 15 calculates an error radius of the calculated position calculated by the positioning unit 13. The other points are the same as those of the first embodiment, and therefore the description will be made with reference to FIG.
[0036]
The calculated position error radius calculator 21 calculates an error radius of the calculated position. The error radius at that time is, for example, GDOP (Geometric Dilution of Precision. Degradation degree of geometric accuracy: calculated based on a deviation of whether or not a satellite used for positioning is located with a small error with respect to the measured position. ) And the error of the propagation distance of each satellite estimated from the state of the signal acquired by the signal analysis unit 12 and the navigation message.
[0037]
The calculated position reliability calculation unit 15 calculates the reliability of the calculated position from the calculated position error radius calculated by the calculated position error radius calculation unit 21. For example, when the error radius of the calculated position calculated by the calculated position error radius calculating unit 21 is 0 m, the reliability of the calculated position is set to 1, and the value of the reliability is reduced as the error radius increases, and the error radius is 100 m or more. , The reliability is set to 0.
[0038]
As described above, according to the present embodiment, it is possible to calculate the reliability of the calculated position based on the calculated position error radius calculated by the calculated position error radius calculation unit 21.
[0039]
In the above-described embodiment, the case has been described where the estimated position calculation unit has the positioning result storage unit. Similar effects can be obtained.
[0040]
(Third embodiment)
FIG. 4 is a block diagram illustrating a configuration of a satellite signal receiver according to the third embodiment of the present invention.
[0041]
In this satellite signal receiver, the calculated position reliability calculation unit 15 calculates a geometric distance between the calculated position calculated by the positioning unit 13 and each satellite, and a signal analysis unit 12. A distance difference calculating unit 32 for calculating a distance difference between the propagation distance of the signal of each satellite acquired in step 2 and the distance calculated by the geometric distance calculating unit 31, and a geometrical difference of each satellite calculated by the distance difference calculating unit 32. A standard deviation calculator 33 for calculating a standard deviation of a distance difference between the distance and the propagation distance.
[0042]
The other points are the same as those of the first embodiment, so that the processing and operation will be described mainly with reference to FIGS. 4 and 5. FIG. 5 is a diagram illustrating a relationship between a calculated position, a geometric distance between the satellite and a propagation distance of a satellite signal according to the third embodiment of the present invention. The geometric distance calculation unit 31 calculates the geometric distances A1 and A2 between the calculated position calculated by the positioning unit 13 and each of the satellites 1 and 2.
[0043]
The distance difference calculator 32 calculates the difference between the propagation distances B1, B2 acquired by the signal analyzer 12 and A1, A2. When the error of the calculated position is small, the difference between A1 and B1 and the difference between A2 and B2 are small values. Conversely, when the error of the calculated position is large, the difference between A1 and B1 and the difference between A2 and B2 are small. Each difference becomes a large value, and each value varies depending on the satellite constellation.
[0044]
Therefore, when the standard deviation calculation unit 33 calculates the standard deviation of the distance difference between the geometric distance and the propagation distance of each satellite, the standard deviation increases when the error in the calculated position is large, and conversely, when the error is small. Since the standard deviation becomes smaller, the reliability of the calculated position can be calculated using the standard deviation calculated by the standard deviation calculator 33.
[0045]
As described above, according to the present embodiment, the reliability of the calculated position can be calculated using the standard deviation calculated by the standard deviation calculation unit 33.
[0046]
In the above embodiment, the case has been described in which the estimated position calculation unit includes the positioning result storage unit, but the present invention is not limited to the case where the positioning position storage unit is included, and may be applied to the case where the estimated position calculation unit includes the independent speed calculation unit. Similar effects can be obtained.
[0047]
(Fourth embodiment)
FIG. 6 is a block diagram illustrating a configuration of a satellite signal receiver according to the fourth embodiment of the present invention. This satellite signal receiver includes a satellite number storage unit 34 in which the calculated position reliability calculation unit 15 stores the number of satellites used in the positioning unit 13. The other points are the same as those of the third embodiment, so that the description will focus on the differences in the processing and operation.
[0048]
In FIG. 6, the number-of-satellite storage unit 34 stores the number of satellites used by the positioning unit 13, and stores the number of satellites when the calculated position reliability calculation unit 15 calculates the reliability of the calculated position. The relationship between the standard deviation calculated by the standard deviation calculation unit 33 and the reliability of the calculated position is changed according to the number of satellites being used.
[0049]
The reason for changing the relationship between the standard deviation and the reliability of the calculated position according to the number of satellites is that the standard deviation tends to increase as the number of satellites increases. Increases the reliability even though the accuracy of the calculated position is poor. Conversely, if the number of satellites is large, there is a possibility that the reliability is reduced despite the accuracy of the calculated position being good That's why.
[0050]
As described above, according to the present embodiment, the reliability of the calculated position is more accurately calculated by changing the relationship between the standard deviation and the reliability of the calculated position according to the number of satellites stored in the satellite number storage unit 34. can do.
[0051]
In the above embodiment, the case has been described in which the estimated position calculation unit includes the positioning result storage unit, but the present invention is not limited to the case where the positioning position storage unit is included, and may be applied to the case where the estimated position calculation unit includes the independent speed calculation unit. Similar effects can be obtained.
[0052]
(Fifth embodiment)
FIG. 7 is a block diagram illustrating a configuration of a satellite signal receiver according to a fifth embodiment of the present invention.
[0053]
In this satellite signal receiver, the calculated position reliability calculating unit 15 stores the altitude at the position indicated by the latitude and longitude in the altitude holding unit 41 and the altitude in the latitude and longitude of the calculated position calculated by the positioning unit 13 in the altitude information. An altitude acquisition unit 42 obtained from the holding unit 41 and an altitude error calculation unit 43 that calculates a difference between the altitude of the calculated position calculated by the positioning unit 13 and the altitude obtained by the altitude acquisition unit 42 and calculates an altitude error of the calculated position. And The other points are the same as those of the first embodiment. Therefore, the description will be made focusing on the differences in the processing and operation.
[0054]
7, the altitude acquisition unit 42 reads the latitude and longitude of the calculated position calculated by the positioning unit 13 and acquires the altitude of a position corresponding to the latitude and longitude from the altitude holding unit 41. The altitude error calculator 43 calculates a difference between the altitude acquired by the altitude acquisition unit 42 and the altitude calculated by the positioning unit 13 to calculate an altitude error of the calculated position. If the altitude error of the calculated position calculated by the positioning unit 13 is large, it is considered that there is a high possibility that the latitude and longitude of the calculated position are also large, so the altitude error of the calculated position is calculated using the altitude error calculated by the altitude error calculation unit 43. Calculate the reliability.
[0055]
As described above, according to the present embodiment, the reliability of the calculated position can be calculated using the height error of the calculated position calculated by the height error calculating unit 43.
[0056]
In the above embodiment, the case has been described in which the estimated position calculation unit includes the positioning result storage unit, but the present invention is not limited to the case where the positioning position storage unit is included, and may be applied to the case where the estimated position calculation unit includes the independent speed calculation unit. Similar effects can be obtained.
[0057]
(Sixth embodiment)
FIG. 8 is a block diagram illustrating a configuration of a satellite signal receiver according to the sixth embodiment of the present invention. In this satellite signal receiver, the estimated position reliability calculator 16 includes a speed error estimator 51 for estimating a previous speed error stored in the positioning result storage 18, and the speed error estimator 51 estimates the error. The reliability of the estimated position is calculated from the previous speed error and the reliability of the corrected position calculated by the corrected position calculation unit 17. The other points are the same as those of the first embodiment, and therefore, the description will focus on the differences in the processing and operation.
[0058]
8, a speed error estimating unit 51 estimates a previous speed error stored in the positioning result storage unit 18. The estimated value of the speed error at that time may be calculated using, for example, an estimated value of the Doppler shift frequency of each satellite, or may be an average value of the speed errors. The estimated position reliability calculator 16 calculates the reliability of the estimated position from the previous speed error calculated by the speed error calculator 51 and the reliability of the corrected position calculated by the corrected position calculator 17.
[0059]
Thus, according to the present embodiment, the reliability of the estimated position can be calculated from the previous speed error and the reliability of the corrected position.
[0060]
In the above embodiment, the case has been described in which the estimated position calculation unit includes the positioning result storage unit, but the present invention is not limited to the case where the positioning position storage unit is included, and may be applied to the case where the estimated position calculation unit includes the independent speed calculation unit. Similar effects can be obtained.
[0061]
(Seventh embodiment)
FIG. 9 is a block diagram illustrating a configuration of a satellite signal receiver according to the seventh embodiment of the present invention. In this satellite signal receiver, the estimated position reliability calculation unit 16 calculates the difference between the previous speed stored in the positioning result storage unit 18 and the current speed calculated by the positioning unit 13 to calculate the speed change. A change calculator 52 is provided. The other points are the same as those of the first embodiment. Therefore, the description will be made focusing on the differences in the processing and operation.
[0062]
In FIG. 9, the speed change calculation unit 52 calculates a speed change from the previous speed stored in the positioning result storage unit 18 and the current speed calculated by the positioning unit 13. When the speed change is equal to or higher than the kinetic performance of the moving object equipped with the satellite signal receiver, specifically, the moving object is a car, and the speed change is calculated as 250 km / h, which is the kinetic performance of the car. If the speed is equal to or higher than the maximum speed, for example, 180 km, it can be determined that the error in the calculated speed is large and the error in the estimated position is also large, so the reliability of the estimated position is calculated using the speed change.
[0063]
As described above, according to the present embodiment, the reliability of the estimated position can be calculated using the speed change calculated by speed change calculating section 52.
[0064]
In the above embodiment, the case has been described in which the estimated position calculation unit includes the positioning result storage unit, but the present invention is not limited to the case where the positioning position storage unit is included, and may be applied to the case where the estimated position calculation unit includes the independent speed calculation unit. Similar effects can be obtained.
[0065]
(Eighth embodiment)
FIG. 10 is a block diagram showing a configuration of a satellite signal receiver according to the eighth embodiment of the present invention. In this satellite signal receiver, the estimated position calculation unit 14 includes an autonomous speed calculation unit 61 that calculates a speed and a speed azimuth by an autonomous sensor instead of the positioning result storage unit 18. The other points are the same as those of the first embodiment. Therefore, the description will be made focusing on the differences in the processing and operation.
[0066]
In FIG. 10, an estimated position calculation unit 14 calculates a speed and a speed direction using an autonomous sensor such as a gyroscope or a vehicle speed pulse.
As described above, according to the present embodiment, since the speed and the speed azimuth calculated by the autonomous sensor are more accurate than the speed and the speed azimuth calculated by the satellite signal receiver, the speed and the speed azimuth calculated by the autonomous speed calculation unit 61 are different. The accuracy of the estimated position and the accuracy of the corrected position can be improved by calculating the estimated position using the obtained speed and speed azimuth.
[0067]
【The invention's effect】
As described above, the present invention uses the previous speed and speed direction stored in the positioning result storage unit or the speed and speed azimuth calculated by the autonomous speed calculation unit and the previous correction position calculated by the correction position calculation unit. Estimated position calculating means for calculating the current estimated position, calculated position reliability calculating means for calculating the reliability of the calculated position calculated by the positioning means, and estimation for calculating the reliability of the estimated position calculated by the estimated position calculating means Position reliability calculating means and correction position calculating means for calculating a corrected position and a corrected position reliability from the calculated position and the estimated position based on the calculated position reliability and the estimated position reliability, Calculating an optimal position from the reliability of the calculated position calculated by the calculated position reliability calculating means and the reliability of the estimated position calculated by the estimated position reliability calculating means for each positioning, thereby causing an error in speed. There can be provided a satellite signal receiver having an excellent effect that it is possible to improve the positioning accuracy without being stored as the accumulated error.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of a satellite signal receiver according to a first embodiment of the present invention.
FIG. 2 is a diagram illustrating a relationship among a calculated position, an estimated position, and a corrected position of the satellite signal receiver according to the first embodiment of the present invention.
FIG. 3 is a block diagram showing a configuration of a satellite signal receiver according to a second embodiment of the present invention.
FIG. 4 is a block diagram illustrating an operation of a satellite signal receiver according to a third embodiment of the present invention.
FIG. 5 is a diagram illustrating a relationship between a calculated position of a satellite signal receiver, a geometric distance to a satellite, and a propagation distance of a satellite signal according to a third embodiment of the present invention.
FIG. 6 is a block diagram illustrating an operation of a satellite signal receiver according to a fourth embodiment of the present invention.
FIG. 7 is a block diagram illustrating a configuration of a satellite signal receiver according to a fifth embodiment of the present invention.
FIG. 8 is a block diagram showing an operation of a satellite signal receiver according to a sixth embodiment of the present invention.
FIG. 9 is a block diagram showing an operation of a satellite signal receiver according to a seventh embodiment of the present invention.
FIG. 10 is a block diagram showing an operation of a satellite signal receiver according to an eighth embodiment of the present invention.
FIG. 11 is a block diagram showing a configuration of a conventional satellite signal receiver.
[Explanation of symbols]
11 Antenna
12 signal analyzer
13 Positioning unit
14 Estimated position calculation unit
15 Calculation position reliability calculation unit
16 Estimated position reliability calculator
17 Correction position calculator
18 Positioning result storage unit
19 Display notification section
21 Calculation position error radius calculation unit
31 Geometric distance calculator
32 Distance difference calculator
33 Standard deviation calculator
34 Satellite Number Storage
41 Altitude Holder
42 Altitude Acquisition Unit
43 Altitude error calculator
51 Speed error estimator
52 Speed change calculator
61 Autonomous speed calculation unit

Claims

An antenna for receiving a signal from a navigation satellite, a signal analyzing means for analyzing a signal received by the antenna to obtain a propagation distance, a Doppler shift frequency, and a navigation message, and a propagation distance obtained by the signal analyzing means. Positioning means for calculating the position, speed, and velocity direction from the Doppler shift frequency and the navigation message, estimated position calculating means for calculating the current estimated position, and the position calculated by the positioning means as the calculated position, the calculated position Calculated position reliability calculating means for calculating the reliability of the estimated position; estimated position reliability calculating means for calculating the reliability of the estimated position calculated by the estimated position calculating means; reliability of the calculated position and reliability of the estimated position. Correction position calculation means for calculating a correction position and the reliability of the correction position from the calculated position and the estimated position by the degree,
The estimated position calculation unit includes a positioning result storage unit that stores the speed and the speed azimuth calculated by the positioning unit,
The previous speed and speed azimuth stored in the positioning result storage means,
A satellite signal receiver, wherein the current estimated position is calculated from a previous correction position calculated by the correction position calculation means.

An antenna for receiving a signal from a navigation satellite, a signal analyzing means for analyzing a signal received by the antenna to obtain a propagation distance, a Doppler shift frequency, and a navigation message, and a propagation distance obtained by the signal analyzing means. Positioning means for calculating the position, speed, and velocity direction from the Doppler shift frequency and the navigation message, estimated position calculating means for calculating the current estimated position, and the position calculated by the positioning means as the calculated position, the calculated position Calculated position reliability calculating means for calculating the reliability of the estimated position; estimated position reliability calculating means for calculating the reliability of the estimated position calculated by the estimated position calculating means; reliability of the calculated position and reliability of the estimated position. Correction position calculation means for calculating a correction position and the reliability of the correction position from the calculated position and the estimated position by the degree,
The estimated position calculating unit includes an autonomous speed calculating unit that calculates a speed and a speed direction by an autonomous sensor,
The speed and speed azimuth calculated by the autonomous speed calculation means,
A satellite signal receiver, wherein the current estimated position is calculated from a previous correction position calculated by the correction position calculation means.

The calculated position reliability calculating unit includes a calculated position error radius calculating unit that calculates an error radius of the calculated position based on the navigation message and a state of a signal from the navigation satellite input to the signal analyzing unit. 3. The satellite signal receiver according to claim 1, wherein the reliability of the calculated position is calculated based on the error radius calculated by the calculated position error radius calculating means.

The calculated position reliability calculating means includes: a geometric distance calculating means for calculating a geometric distance between a position of a navigation satellite calculated from a navigation message obtained by the signal analyzing means and the calculated position; Distance difference calculating means for calculating a distance difference between the propagation distance of the signal of each navigation satellite obtained by the means and the geometric distance calculated by the geometric distance calculating means, and the distance calculated by the distance difference calculating means 3. The satellite according to claim 1, further comprising standard deviation calculating means for calculating a standard deviation of the difference, wherein the reliability of the calculated position is calculated based on the standard deviation calculated by the standard deviation calculating means. Signal receiver.

The calculated position reliability calculation means includes satellite number storage means for storing the number of navigation satellites used in the positioning means, and the reliability of the calculated position is determined by the number of navigation satellites stored in the satellite number storage means. 5. The satellite signal receiver according to claim 4, wherein:

The calculated position reliability calculating means includes an altitude holding means for holding an altitude at a position indicated by latitude and longitude, and an altitude obtaining means for obtaining an altitude corresponding to the latitude and longitude of the calculated position from the altitude holding means. And an altitude error calculating unit that calculates a difference between the altitude of the calculated position calculated by the positioning unit and the altitude obtained by the altitude obtaining unit and calculates an altitude error of the calculated position. The satellite signal receiver according to claim 1 or 2, wherein the reliability of the calculated position is calculated based on the altitude error of the calculated position calculated by (1).

The estimated position reliability calculating means includes a speed error estimating means for estimating the error of the previous speed, and the reliability of the previous speed error estimated by the speed error estimating means and the corrected position calculated by the corrected position calculating means. 7. The satellite signal receiver according to claim 1, wherein the degree of reliability of the estimated position is calculated from the degree.

The estimated position reliability calculating means includes a speed change calculating means for calculating a speed change from the current speed calculated by the positioning means and the previous speed, based on the speed change calculated by the speed change calculating means. The satellite signal receiver according to claim 1, wherein reliability of the estimated position is calculated.