JP4060038B2 - Noise evaluation method, noise evaluation device, GPS receiver arrangement method, electronic device, and vehicle - Google Patents

Description

【００３５】
最後に、制御装置７Ａが上記式（９）に従って算出した各スプリアスノイズの受信レベルの総和値と所定の規格値とを比較する。ここでは、所定の規格値を例えば−ＡｄＢμＶとする。この比較結果として、スプリアスノイズの受信レベルの総和値が所定の規格値−ＡｄＢμＶ以下であれば、制御装置７ＡはＧＰＳ受信装置の受信性能に問題のないスプリアスノイズの受信レベルであると判定し、所定の規格値以上であるとＧＰＳ受信装置の受信性能が許容範囲内にないものと判定する（ノイズ評価ステップ）。
【００３６】
上述のように、スプリアスノイズによってＧＰＳ受信装置の受信性能が許容範囲内にないものと判定されると、車輌２内に搭載されているノイズ発生源となり得る不図示の電子機器とＧＰＳアンテナ３などから構成されるＧＰＳ受信装置との相対的距離を変更する（距離変更ステップ）。ここで言う相対的距離の変更では、ＧＰＳ受信装置若しくは電子機器のどちらを基準にして変更してもよい（つまり、ＧＰＳ受信装置若しくは電子機器のどちらかの配置場所を固定として、他方を移動させて変更してもよく、この固定側、移動側の選択は車輌２内で適宜行われる）。
【００３７】
不図示の電子機器とＧＰＳアンテナ３などから構成されるＧＰＳ受信装置との相対的距離を変更するごとに、上述したスペクトルアナライザ７によるＧＰＳ信号のスペクトル拡散信号の周波数帯域に含まれるスプリアスノイズの周波数及び受信レベルの測定から制御装置７Ａによるスプリアスノイズの評価までの動作を、スプリアスノイズの受信レベルがスペクトル拡散信号の受信における許容可能な範囲と判定されるまで繰り返す。
【００３８】
上記ノイズの評価によってスプリアスノイズの受信レベルがスペクトル拡散信号の受信における許容可能な範囲になると、制御装置７Ａがこのときの電子機器とＧＰＳ受信装置との相対的距離をＧＰＳ受信装置の受信性能を最適化するものとして決定する。制御装置７Ａによって、最適化された電子機器とＧＰＳ受信装置との相対的距離を満たすように、車輌２内に電子機器及びＧＰＳ受信装置を配置する（配置ステップ）。
このようにして、制御装置７Ａが決定した相対的距離を満たすように、電子機器とＧＰＳ受信装置とを配置した車輌は、ＧＰＳ受信におけるスプリアスノイズが定量的に評価されて、この影響が最低限に抑えられている。
【００３９】
以上のように、この実施の形態１によれば、受信すべきＧＰＳ信号をスペクトル拡散させたスペクトル拡散信号の周波数帯域に含まれるノイズ信号の周波数及び受信レベルを求め、このノイズ信号に対して受信すべき信号の中心周波数からの離調周波数に応じた受信レベルの重み付けを加え、この重み付けを加えたノイズ信号の受信レベルの総和値を算出して所定の規格値と比較し、これによりスペクトル拡散信号の受信における許容可能なノイズ信号の受信レベルであるか否かを評価するので、ＧＰＳ帯域の受信性能に妨害を与えるノイズを定量的に規定することができる。
【００４０】
また、この実施の形態１によれば、ノイズ発生源となり得る電子機器とともに車輌２に搭載され、ＧＰＳ帯域のスペクトル拡散信号を受信するＧＰＳアンテナ３などから構成されるＧＰＳ受信装置に対して、上記実施の形態１に示したノイズ評価方法を用いてスペクトル拡散信号の他に受信されるノイズ信号の受信レベルを評価し、評価されたノイズ信号の受信レベルがスペクトル拡散信号の受信における許容可能な範囲にないとき、ＧＰＳ受信装置と電子機器との相対的距離を変更し、この変更の結果としてノイズ信号の受信レベルがスペクトル拡散信号の受信における許容可能な範囲となる相対的距離が得られると、この相対的距離を満たすようにＧＰＳ受信装置と電子機器とを車輌２内に配置するので、ノイズ発生源となり得る電子機器からのＧＰＳ帯域のノイズの影響を最低限に抑えた位置にＧＰＳアンテナ３などから構成されるＧＰＳ受信装置を配置することができ、ＧＰＳ帯域の受信性能に優れた車輌２を提供することができる。
【００４１】
実施の形態２．
この実施の形態２によるノイズ評価方法を実現するノイズ評価装置の制御装置７Ａでは、受信すべきＧＰＳ信号の中心周波数からの離調周波数ごとのスプリアスノイズのピーク本数に応じた受信レベルの規格値を格納するメモリ（規格値記憶手段）を設けておく。
【００４２】
次に動作について説明する。
この実施の形態２においても、上記実施の形態１と同様に、図１に示す構成、即ち、ノイズ発生源となり得る電子機器とともに、ＧＰＳ受信装置を搭載した車輌２に対して評価を行った場合について説明する。
先ず、バイアスティ４、増幅器５ａ，５ｂを介して、ＧＰＳアンテナ３が受信したＧＰＳ信号をスペクトルアナライザ７で測定し、ＧＰＳ信号のスペクトル拡散信号の周波数帯域に含まれるスプリアスノイズの周波数及び受信レベルを求める（ノイズ抽出ステップ）。ここまでの動作は上記実施の形態１と同様である。
【００４３】
次に、制御装置７Ａがスペクトルアナライザ７によって周波数及び受信レベルを求めたスプリアスノイズに対して受信すべきＧＰＳ信号の中心周波数からの離調周波数に応じた受信レベルを算出し、これと上記メモリに格納しておいたＧＰＳ信号の中心周波数からの離調周波数ごとのスプリアスノイズのピーク本数に応じた受信レベルの規格値とを比較する。
具体的には、例えば図３に示すようなＧＰＳ帯域のスプリアスノイズの許容受信レベルの規格値をメモリに予め設定しておく。この規格値は、下記式（１０）にＧＰＳ信号の中心周波数からの離調周波数とそのときのノイズピーク本数を代入して算出する。
Ｔ（Δｆ）＋１０ｌｏｇ（１／ｎ）−Ｂ ・・・（１０）
また、図３における黒塗りの四角記号のプロット、黒塗りの三角記号のプロット、×記号のプロット、黒塗りの丸記号のプロットで示されるノイズピークの本数がそれぞれ２本、３本、５本、１０本における関係も、上記式（１０）を用いて算出したものである。
【００４４】
上述した比較動作によって、ＧＰＳ信号の中心周波数からの離調周波数Δｆに対応するスプリアスノイズが図３に示す規格値以下であれば、制御装置７ＡはＧＰＳ受信装置の受信性能に問題のないスプリアスノイズの受信レベルであると判定し、上記規格値以上であるとＧＰＳ受信装置の受信性能が許容範囲内にないものと判定する（ノイズ評価ステップ）。
ここで、スプリアスノイズがＧＰＳ受信装置の受信性能における許容範囲内にないものと判定されると、再びＧＰＳ帯域のスプリアスノイズの測定を行って上記実施の形態１で示したノイズ評価方法でノイズ評価を行う。
【００４５】
上記実施の形態１で示したノイズ評価方法においても、測定されたスプリアスノイズがＧＰＳ受信装置の受信性能における許容範囲内にないものと判定されると、車輌２内に搭載されているノイズ発生源となり得る不図示の電子機器とＧＰＳアンテナ３などから構成されるＧＰＳ受信装置との相対的距離を変更する（距離変更ステップ）。この相対的距離の変更動作は、上記実施の形態１と同様に、ＧＰＳ受信装置若しくは電子機器のどちらかの配置場所を固定として他方を移動させて変更してもよく、この固定側や移動側の選択は車輌２内で適宜行われる。
【００４６】
不図示の電子機器とＧＰＳアンテナ３などから構成されるＧＰＳ受信装置との相対的距離を変更するごとに、上述したスペクトルアナライザ７によるＧＰＳ信号のスペクトル拡散信号の周波数帯域に含まれるスプリアスノイズの周波数及び受信レベルの測定から制御装置７Ａによるスプリアスノイズの評価までの動作を、スプリアスノイズの受信レベルがスペクトル拡散信号の受信における許容可能な範囲と判定されるまで繰り返す。
【００４７】
上記ノイズの評価によってスプリアスノイズの受信レベルがスペクトル拡散信号の受信における許容可能な範囲になると、制御装置７Ａがこのときの電子機器とＧＰＳ受信装置との相対的距離をＧＰＳ受信装置の受信性能を最適化するものとして決定する。制御装置７Ａによって、最適化された電子機器とＧＰＳ受信装置との相対的距離を満たすように、車輌２内に電子機器及びＧＰＳ受信装置を配置する（配置ステップ）。
このようにして、制御装置７Ａが決定した相対的距離を満たすように、電子機器とＧＰＳ受信装置とを配置した車輌は、ＧＰＳ受信におけるスプリアスノイズが定量的に評価されて、この影響が最低限に抑えられている。
【００４８】
以上のように、この実施の形態２によれば、受信すべきＧＰＳ信号をスペクトル拡散させたスペクトル拡散信号の周波数帯域に含まれるノイズ信号の周波数及び受信レベルを求め、このノイズ信号に対して受信すべき信号の中心周波数からの離調周波数に応じた受信レベルを算出し、これと予め設定した受信すべき信号の中心周波数からの離調周波数ごとのノイズ信号のピーク本数に応じた受信レベルの規格値とを比較して、スペクトル拡散信号の受信における許容可能なノイズ信号の受信レベルであるか否かを評価するので、上記実施の形態１と同様の効果が得られる。
【００４９】
また、この実施の形態２によれば、ノイズ発生源となり得る電子機器とともに車輌２に搭載され、ＧＰＳ帯域のスペクトル拡散信号を受信するＧＰＳアンテナ３などから構成されるＧＰＳ受信装置に対して、上記実施の形態２に示したノイズ評価方法を用いてスペクトル拡散信号の他に受信されるノイズ信号の受信レベルを評価し、評価されたノイズ信号の受信レベルがスペクトル拡散信号の受信における許容可能な範囲にないとき、ＧＰＳ受信装置と電子機器との相対的距離を変更し、この変更の結果としてノイズ信号の受信レベルがスペクトル拡散信号の受信における許容可能な範囲となる相対的距離が得られると、この相対的距離を満たすようにＧＰＳ受信装置と電子機器とを車輌２内に配置するので、ノイズ発生源となり得る電子機器からのＧＰＳ帯域のノイズの影響を最低限に抑えた位置にＧＰＳアンテナ３などから構成されるＧＰＳ受信装置を配置することができ、ＧＰＳ帯域の受信性能に優れた車輌２を提供することができる。
【００５０】
なお、上記実施の形態１又は上記実施の形態２に示した車輌２は、ノイズ発生源となり得る電子機器とともに、ＧＰＳ帯域のスペクトル拡散信号を受信するＧＰＳ受信装置を搭載し、上記実施の形態１又は上記実施の形態２に示したノイズ評価方法を用いて電子機器がＧＰＳ受信装置に与えるスプリアスノイズの受信レベルが評価されるので、ＧＰＳ帯域の受信性能に妨害を与えるノイズが定量的に規定されていることから、ＧＰＳ帯域の受信性能を改善する際におけるノイズ影響の指標とすることができる。
【００５１】
さらに、上記実施の形態１又は上記実施の形態２に示した車輌２は、上記実施の形態１又は上記実施の形態２に示すようにして、ＧＰＳ帯域のスペクトル拡散信号を受信するＧＰＳ受信装置に与えるノイズ信号の受信レベルがスペクトル拡散信号の受信における許容可能な範囲となる相対的距離が求められ、この相対的距離を満たす位置に電子機器やＧＰＳ受信装置が配置されるので、ＧＰＳ帯域の受信性能に優れている。
【００５２】
実施の形態３．
図４はこの発明の実施の形態３によるノイズ評価装置の構成を示す図であり、図５は図４の上面図である。図において、７Ｂは制御装置（ノイズ抑圧重み付け手段、ノイズ総和値算出手段、ノイズ評価手段）であって、基本的には上記実施の形態１の制御装置７Ａと同様に、スペクトルアナライザ７が抽出したノイズ信号の受信レベルに対してＧＰＳ信号の中心周波数からの離調周波数に応じた受信レベルの重み付けを加え、重み付けを加えたノイズ信号の受信レベルの総和値を算出して所定の規格値と比較し、スペクトル拡散信号の受信における許容可能なノイズ信号の受信レベルであるか否かを評価する。この制御装置７Ｂは上記動作を実行させるプログラムを格納するコンピュータシステムによって実現できる。８はノイズ評価の対象である電子機器、９は電子機器８を設置する発泡スチロール台であって、ホーンアンテナ１３の開口中心と電子機器８との高を合わせるとともに、電子機器８をグランドプレーン１０から電気的に遮断する。１０は測定台１１の上面に設置したグランドプレーン、１１は測定台で、グランドプレーン１０から地面１２までの高さを１ｍに保っている。
【００５３】
１３は電子機器８からのノイズを受信するホーンアンテナ（ＧＰＳ受信装置）で、１３ａはホーンアンテナ１３を設置する支持棒（ＧＰＳ受信装置）である。また、ホーンアンテナ１３の開口部から電子機器８までの距離Ｌは、電子機器８の種類や通常の設置部位などによって決定される。例えば、電子機器８がＧＰＳアンテナ３の直近に設置されるものであるならば、測定者の協議で適宜決定するものとし、電子機器８が車室内に設置されるものであれば距離Ｌを２５ｃｍ、車室外に設置されるものであれば距離Ｌを１００ｃｍとする。１４は電子機器８に電源を供給する電源回路である。なお、図１と同一構成要素には同一符号を付して重複する説明を省略する。
【００５４】
次に動作について説明する。
先ず、増幅器５ａ，５ｂを介して、ホーンアンテナ１３が受信したＧＰＳ帯域のスプリアスノイズをスペクトルアナライザ７で測定し、スプリアスノイズの周波数及び受信レベルを求める（ノイズ抽出ステップ）。
具体的には、スペクトル拡散によって広帯域となったＧＰＳ信号に対して、例えば下記のようなスペクトルアナライザ７の設定にする。
スペクトルアナライザ７の狭帯域測定において、ＧＰＳ信号の中心周波数ｆｏを１．５７５４２ＧＨｚ、測定スパンを２．０ＭＨｚ、ＲＢＷを３．０ｋＨｚ、ＶＢＷを３．０ｋＨｚ、走査時間を５６０ｍｓとし、受信信号のレベルを５ｄＢごと（５ｄＢ／ＤＩＶ）に表示し、オフセットをホーンアンテナ１３の絶対利得Ｇ_Ａ（ｄＢｉ）と増幅器５ａ，５ｂの利得Ｇ_Ｂとの和Ｇ_Ａ＋Ｇ_Ｂ（ｄＢ）として設定する。また、スペクトルアナライザ７の広帯域測定においては、ＧＰＳ信号の中心周波数ｆｏを１．５７５４２ＧＨｚ、測定スパンを１０ＭＨｚ、ＲＢＷを１０ｋＨｚ、ＶＢＷを１０ｋＨｚ、走査時間を５６０ｍｓとし、受信信号のレベルを５ｄＢごと（５ｄＢ／ＤＩＶ）に表示し、オフセットをホーンアンテナ１３の絶対利得Ｇ_Ａ（ｄＢｉ）と増幅器５ａ，５ｂの利得Ｇ_Ｂとの和Ｇ_Ａ＋Ｇ_Ｂ（ｄＢ）として設定する。
【００５５】
また、ホーンアンテナ１３の総合利得値Ｇ_Ａは、電源回路１４とホーンアンテナ１３とを接続するケーブルにおける損失を含めるものとする。さらに、不図示の回転駆動回路を介してホーンアンテナ１３を支持棒１３ａに設置して、ホーンアンテナ１３をその開口中心に回転可能とする。これはホーンアンテナ１３の開口部の形状が矩形で水平方向と垂直方向とで長さが異なるため、例えば水平方向に開口部の長辺がくる位置で測定を行ったあと、回転させて水平方向に開口部の短辺がくる位置にしてから測定を行うようにする。
【００５６】
次に、制御装置７Ｂがスペクトルアナライザ７によって周波数及び受信レベルを求めたスプリアスノイズに対して受信すべきＧＰＳ信号の中心周波数からの離調周波数に応じた受信レベルの重み付けを加える（ノイズ抑圧重み付けステップ）。
【００５７】
また、この実施の形態３においても、上述したＧＰＳ信号の中心周波数ｆｏからの離調周波数Δｆごとのノイズのピーク本数ｎは、単にノイズパルスのピーク本数のみを指すものではなく、上記実施の形態１と同様に、図２に示すような広帯域のノイズの場合、スペクトルアナライザ７によって測定スパンの周波数ごとにサンプリングされた受信レベルのうち、スプリアスノイズに対応するサンプル値の数も、ＧＰＳ信号の中心周波数ｆｏからの離調周波数Δｆごとのノイズのピーク本数ｎに含むものとする。
【００５８】
上述のようにして、ＧＰＳ信号の中心周波数ｆｏから周波数Δｆだけ離調した各スプリアスノイズの受信レベルに対して重み付けが加えられると、制御装置７Ｂが重み付けを加えた各スプリアスノイズの受信レベルの総和値を算出する（ノイズ総和値算出ステップ）。具体的には、上記実施の形態１と同様に上記式（９）に従って重み付けを加えた各スプリアスノイズの受信レベルの総和値を算出する。
【００５９】
最後に、制御装置７Ｂが上記式（９）に従って算出した各スプリアスノイズの受信レベルの総和値と所定の規格値とを比較する。この比較結果として、スプリアスノイズの受信レベルの総和値が所定の規格値以下であれば、制御装置７ＢはＧＰＳ受信装置の受信性能に問題のない受信レベルのスプリアスノイズを発生する電子機器８であると判定し、所定の規格値以上であるとＧＰＳ受信装置の受信性能における許容範囲内にない受信レベルのスプリアスノイズを発生する電子機器８であると判定する（ノイズ評価ステップ）。
【００６０】
上述のように、ＧＰＳ受信装置の受信性能における許容範囲内にない受信レベルのスプリアスノイズを発生する電子機器８であると判定されると、電子機器８とホーンアンテナ１３の開口部との距離Ｌを変更する（距離変更ステップ）。
【００６１】
電子機器８とホーンアンテナ１３の開口部との距離Ｌを変更するごとに、上述した電子機器８からのＧＰＳ帯域スプリアスノイズの周波数及び受信レベルのスペクトルアナライザ７による測定から制御装置７Ｂによるスプリアスノイズの評価までの動作を、スプリアスノイズの受信レベルがスペクトル拡散信号の受信における許容可能な範囲と判定されるまで繰り返す。
【００６２】
上記ノイズの評価によってスプリアスノイズの受信レベルがスペクトル拡散信号の受信における許容可能な範囲になると、制御装置７Ｂがこのときの電子機器８とホーンアンテナ１３の開口部との距離ＬをＧＰＳ受信装置の受信性能を最適化するものとして決定する（相対的距離決定ステップ）。制御装置７Ｂによって、最適化された電子機器とホーンアンテナ１３の開口部との距離Ｌを満たすように、車輌２内に電子機器及びＧＰＳ受信装置を配置する（配置ステップ）。
このようにして、制御装置７Ｂが決定した相対的距離を満たすように、電子機器とＧＰＳ受信装置とを配置した車輌は、ＧＰＳ受信におけるスプリアスノイズが定量的に評価されて、この影響が最低限に抑えられている。
【００６３】
また、この実施の形態３においても上記実施の形態２を適用することができる。この場合、制御装置７Ｂに受信すべきＧＰＳ信号の中心周波数からの離調周波数ごとのスプリアスノイズのピーク本数に応じた受信レベルの規格値を格納するメモリ（規格値記憶手段）を設けておく。
【００６４】
次に動作について説明する。
上記と同様にして、増幅器５ａ，５ｂを介して、電子機器８が発生したＧＰＳ帯域のスプリアスノイズの周波数及び受信レベルを、スペクトルアナライザ７で測定する（ノイズ抽出ステップ）。
次に、スペクトルアナライザ７によって周波数及び受信レベルを求めたスプリアスノイズに対して受信すべきＧＰＳ信号の中心周波数からの離調周波数に応じた受信レベルを制御装置７Ｂが算出し、これと上記メモリに格納しておいたＧＰＳ信号の中心周波数からの離調周波数ごとのスプリアスノイズのピーク本数に応じた受信レベルの規格値とを比較する。
具体的には、上記実施の形態２と同様に、例えば図３に示すようなＧＰＳ帯域のスプリアスノイズの許容受信レベルの規格値をメモリに予め設定しておく。
【００６５】
上述した比較動作によって、ＧＰＳ信号の中心周波数からの離調周波数Δｆに対応するスプリアスノイズが図３に示す規格値以下であれば、制御装置７ＢはＧＰＳ受信装置の受信性能に問題のない受信レベルのスプリアスノイズを発生する電子機器８であると判定し、上記規格値以上であるとＧＰＳ受信装置の受信性能における許容範囲内にない受信レベルのスプリアスノイズを発生する電子機器８であると判定する（ノイズ評価ステップ）。
ここで、スプリアスノイズがＧＰＳ受信装置の受信性能における許容範囲内にないものと判定されると、再びＧＰＳ帯域のスプリアスノイズの測定を行って上記実施の形態１で示したノイズ評価方法でノイズ評価を行う。
これ以降の動作は上記実施の形態と同様であるので重複する説明を省略する。
【００６６】
以上のように、この実施の形態３によれば、ノイズ発生源となり得る電子機器８と所定の距離だけ離れて配置され、ＧＰＳ帯域の信号をスペクトル拡散したスペクトル拡散信号を受信するホーンアンテナ１３に対して、上記実施の形態１又は上記実施の形態２に示したノイズ評価方法を用いてスペクトル拡散信号の他に受信されるノイズ信号の受信レベルを評価し、評価したノイズ信号の受信レベルがスペクトル拡散信号の受信における許容可能な範囲にないとき、ＧＰＳ受信装置と電子機器との所定の距離を変更し、この変更の結果としてノイズ信号の受信レベルがスペクトル拡散信号の受信における許容可能な範囲となる所定の距離が得られると、これをＧＰＳ受信装置の受信性能を最適化する電子機器とＧＰＳ受信装置との相対的距離として決定するので、ノイズ発生源となり得る電子機器８からのＧＰＳ帯域のスプリアスノイズの影響を低減させたＧＰＳ受信装置の設置位置を決定する指標である相対的距離を提供することができる。
【００６７】
また、この実施の形態３に示した電子機器８は、上記実施の形態１から３に示したノイズ評価方法を用いてＧＰＳ帯域のスペクトル拡散信号を受信するホーンアンテナ１３からなるＧＰＳ受信装置に与えるノイズ信号の受信レベルが評価されるので、ＧＰＳ帯域の受信性能に妨害を与えるノイズが定量的に規定されており、車輌などに搭載する際のノイズ影響の指標とすることができる。
【００６８】
さらに、この実施の形態３に示した電子機器８は、上記実施の形態に示すようにして、ＧＰＳ帯域のスペクトル拡散信号を受信するホーンアンテナ１３からなるＧＰＳ受信装置に与えるノイズ信号の受信レベルがスペクトル拡散信号の受信における許容可能な範囲となる相対的距離が求められ、この相対的距離を満たす位置に配置されるので、自己が発生するノイズがＧＰＳ受信装置に与える影響を低減することができ、ＧＰＳ帯域の受信性能を最適化することができる。
【００６９】
さらに、上記実施の形態１から３によるノイズ評価方法やノイズ評価装置をＧＰＳ（Ｇｌｏｂａｌ Ｐｏｓｉｔｉｏｎｉｎｇ Ｓｙｓｔｅｍ）に使用するので、スペクトル拡散方式を採用するＧＰＳにおけるノイズを定量的に規定することができる。
【００７０】
【発明の効果】
以上のように、この発明によれば、受信すべき信号をスペクトル拡散させたスペクトル拡散信号の周波数帯域に含まれるノイズ信号の周波数及び受信レベルを求めるノイズ抽出ステップと、ノイズ信号に対して受信すべき信号の中心周波数からの離調周波数に応じた受信レベルの重み付けを加えるノイズ抑圧重み付けステップと、このノイズ抑圧重み付けステップで重み付けを加えたノイズ信号の受信レベルの総和値を算出するノイズ総和値算出ステップと、ノイズ総和値算出ステップで算出したノイズ信号の受信レベルの総和値と所定の規格値とを比較して、スペクトル拡散信号の受信における許容可能なノイズ信号の受信レベルであるか否かを評価するノイズ評価ステップとを備えるので、受信すべき信号をスペクトル拡散させたスペクトル拡散信号の周波数帯域の受信性能に妨害を与えるノイズ信号を定量的に規定することができるという効果がある。
【００７１】
この発明によれば、受信すべき信号をスペクトル拡散させたスペクトル拡散信号の周波数帯域に含まれるノイズ信号の周波数及び受信レベルを求めるノイズ抽出ステップと、ノイズ信号に対して受信すべき信号の中心周波数からの離調周波数に応じた受信レベルを算出し、これと予め設定した受信すべき信号の中心周波数からの離調周波数ごとのノイズ信号のピーク本数に応じた受信レベルの規格値とを比較して、スペクトル拡散信号の受信における許容可能なノイズ信号の受信レベルであるか否かを評価するノイズ評価ステップとを備えるので、上記段落００７０と同様の効果が得られるとともに、ノイズ信号のピーク本数を用いて規格値を適宜変更することでノイズに対する適切な評価値を提供することができるという効果がある。
【００７２】
この発明によれば、ＧＰＳ（Ｇｌｏｂａｌ Ｐｏｓｉｔｉｏｎｉｎｇ Ｓｙｓｔｅｍ）に使用するので、スペクトル拡散方式を採用するＧＰＳにおけるノイズを定量的に規定することができるという効果がある。
【００７３】
この発明によれば、受信すべき信号をスペクトル拡散させたスペクトル拡散信号の周波数帯域に含まれるノイズ信号の周波数及び受信レベルを求めるノイズ抽出手段と、ノイズ信号に対して受信すべき信号の中心周波数からの離調周波数に応じた受信レベルの重み付けを加えるノイズ抑圧重み付け手段と、このノイズ抑圧重み付け手段によって重み付けを加えたノイズ信号の受信レベルの総和値を算出するノイズ総和値算出手段と、ノイズ総和値算出手段が算出したノイズ信号の受信レベルの総和値と所定の規格値とを比較して、スペクトル拡散信号の受信における許容可能なノイズ信号の受信レベルであるか否かを評価するノイズ評価手段とを備えるので、受信すべき信号をスペクトル拡散させたスペクトル拡散信号の周波数帯域の受信性能に妨害を与えるノイズ信号を定量的に規定するノイズ評価装置を提供することができるという効果がある。
【００７４】
この発明によれば、受信すべき信号をスペクトル拡散させたスペクトル拡散信号の周波数帯域に含まれるノイズ信号の周波数及び受信レベルを求めるノイズ抽出手段と、受信すべき信号の中心周波数からの離調周波数ごとのノイズ信号のピーク本数に応じた受信レベルの規格値を記憶する規格値記憶手段と、ノイズ抽出手段が周波数及び受信レベルを求めたノイズ信号に対して受信すべき信号の中心周波数からの離調周波数に応じた受信レベルを算出し、これと規格値記憶手段に記憶した受信すべき信号の中心周波数からの離調周波数ごとのノイズ信号のピーク本数に応じた受信レベルの規格値とを比較して、スペクトル拡散信号の受信における許容可能なノイズ信号の受信レベルであるか否かを評価するノイズ評価手段とを備えるので、上記段落００７３と同様の効果を得ることができる。
【００７５】
この発明によれば、ＧＰＳに使用することを特徴とするので、スペクトル拡散方式を採用するＧＰＳにおけるノイズを定量的に規定するノイズ評価装置を提供することができるという効果がある。
【００７６】
この発明によれば、ノイズ発生源となり得る電子機器と所定の距離だけ離れて配置され、ＧＰＳ帯域の信号をスペクトル拡散したスペクトル拡散信号を受信するＧＰＳ受信装置に対して、上記ノイズ評価方法を用いてスペクトル拡散信号の他に受信されるノイズ信号の受信レベルを評価するノイズ評価ステップと、このノイズ評価ステップで評価されたノイズ信号の受信レベルがスペクトル拡散信号の受信における許容可能な範囲にないとき、ＧＰＳ受信装置と電子機器との所定の距離を変更する距離変更ステップと、この距離変更ステップでの変更の結果として得られるノイズ信号の受信レベルがスペクトル拡散信号の受信における許容可能な範囲となる所定の距離を、ＧＰＳ受信装置の受信性能を最適化する電子機器とＧＰＳ受信装置との相対的距離として決定する相対的距離決定ステップとを備えるので、ノイズ発生源となり得る電子機器からのＧＰＳ帯域のノイズ信号の影響を低減させたＧＰＳ受信装置の設置位置を決定する指標である相対的距離を提供することができるという効果がある。
【００７７】
この発明によれば、ノイズ発生源となり得る電子機器とともに車輌に搭載され、ＧＰＳ帯域の信号をスペクトル拡散したスペクトル拡散信号を受信するＧＰＳ受信装置に対して、上記ノイズ評価方法を用いてスペクトル拡散信号の他に受信されるノイズ信号の受信レベルを評価するノイズ評価ステップと、このノイズ評価ステップで評価されたノイズ信号の受信レベルがスペクトル拡散信号の受信における許容可能な範囲にないとき、ＧＰＳ受信装置と電子機器との相対的距離を変更する距離変更ステップと、この距離変更ステップでの変更の結果としてノイズ信号の受信レベルがスペクトル拡散信号の受信における許容可能な範囲となる相対的距離が得られると、この相対的距離を満たすようにＧＰＳ受信装置と電子機器とを車輌内に配置する配置ステップとを備えるので、ノイズ発生源となり得る電子機器からのＧＰＳ帯域のノイズの影響を最低限に抑えた位置にＧＰＳ受信装置を配置することができ、ＧＰＳ帯域の受信性能に優れた車輌を提供することができるという効果がある。
【００７８】
この発明によれば、上記ノイズ評価方法を用いてＧＰＳ帯域の信号をスペクトル拡散したスペクトル拡散信号を受信するＧＰＳ受信装置に与えるノイズ信号の受信レベルが評価されたことを特徴とするので、ＧＰＳ帯域の受信性能に妨害を与えるノイズ信号が定量的に規定されていおり、車輌などに搭載する際のノイズ影響の指標とすることができるという効果がある。
【００７９】
この発明によれば、ノイズ発生源となり得る電子機器とともに、ＧＰＳ帯域の信号をスペクトル拡散したスペクトル拡散信号を受信するＧＰＳ受信装置を搭載し、上記ノイズ評価方法を用いて電子機器がＧＰＳ受信装置に与えるノイズ信号の受信レベルが評価されたことを特徴とするので、ＧＰＳ帯域の受信性能に妨害を与えるノイズが定量的に規定されていることから、ＧＰＳ帯域の受信性能を改善する際におけるノイズ影響の指標とすることができるという効果がある。
【００８０】
この発明によれば、上記ＧＰＳ受信装置の配置方法を用いてＧＰＳ帯域の信号をスペクトル拡散したスペクトル拡散信号を受信するＧＰＳ受信装置に与えるノイズ信号の受信レベルがスペクトル拡散信号の受信における許容可能な範囲となる相対的距離を求め、この相対的距離を満たす位置に配置したことを特徴とするので、自己が発生するノイズ信号がＧＰＳ受信装置に与える影響を低減することができ、ＧＰＳ帯域の受信性能を最適化することができるという効果がある。
【００８１】
この発明によれば、上記ＧＰＳ受信装置の配置方法を用いてＧＰＳ帯域の信号をスペクトル拡散したスペクトル拡散信号を受信するＧＰＳ受信装置及びノイズ発生源となり得る電子機器を配置したので、ＧＰＳ帯域の受信性能に優れているという効果がある。
【図面の簡単な説明】
【図１】 この発明の実施の形態１によるノイズ評価装置の構成を示す図である。
【図２】 帯域幅を有するノイズの例を示す図である。
【図３】 ＧＰＳ帯域のスプリアスノイズの許容受信レベルの規格値を示す図である。
【図４】 この発明の実施の形態３によるノイズ評価装置の構成を示す図である。
【図５】 図４の上面図である。
【図６】 ＧＰＳ信号に対するスペクトル拡散を説明する説明図である。
【図７】 ＧＰＳ受信装置の受信感度とノイズ信号の周波数との関係を示すグラフ図である。
【図８】 ＧＰＳ信号の受信に際して発生したノイズ信号のパターンを示す図である。
【符号の説明】
１ 電波暗室、２ 車輌、３ ＧＰＳアンテナ（ＧＰＳ受信装置）、４ バイアスティ、５ａ，５ｂ 増幅器、６ 増幅器用の電源回路、７ スペクトルアナライザ（ノイズ抽出手段）、７Ａ，７Ｂ 制御装置（ノイズ抑圧重み付け手段、ノイズ総和値算出手段、評価手段）、８ 電子機器、９ 発泡スチロール台、１０ グランドプレーン、１１ 測定台、１２ 地面、１３ ホーンアンテナ（ＧＰＳ受信装置）、１３ａ 支持棒（ＧＰＳ受信装置）、１４ 電源回路。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a noise evaluation method for receiving a spread spectrum signal, and more particularly to the reception level of a noise signal applied to a GPS receiver that receives a spread spectrum signal obtained by spreading a signal in a GPS (Global Positioning System) band. By using this noise evaluation method together with a noise evaluation method and a noise evaluation device capable of performing accurate and quantitative noise evaluation by weighting according to the detuning frequency from the center frequency of the GPS band signal. Electronic device and vehicle in which noise applied to GPS receiver is evaluated, and arrangement of GPS receiver for obtaining relative distance between electronic device and GPS receiver that optimizes reception performance of GPS receiver using the noise evaluation method Method, and the relative distance obtained by the positioning method of the GPS receiver. Electronics disposed in a position to meet, and to a vehicle in which a GPS receiver and an electronic device in a position satisfying the relative distance obtained by arranging method of the GPS receiver is located.
[0002]
[Prior art]
The GPS receiver receives signals from GPS satellites in orbit around the earth and measures the position and the like. A signal transmitted from the GPS satellite to the GPS receiver is spread by the GPS satellite and converted into a spread spectrum signal having a wider band than the signal to be received.
[0003]
FIG. 6 is an explanatory diagram for explaining spread spectrum for the GPS signal described above, (a) shows a data signal to be received by the GPS receiver and a spread spectrum signal obtained by spreading the spectrum, and (b) shows a spread spectrum signal. And a noise signal received therewith, and (c) shows a demodulated signal and a noise signal demodulated by despreading the spread spectrum signal. As shown in FIG. 6A, the data signal to be received by the GPS receiver d (t) becomes a broadband spread spectrum signal s (t) by spread spectrum. A data signal to be received by the GPS receiver is a spread signal that spreads the spectrum of d (t). ₁ Assuming that (t), the spread spectrum signal s (t) is expressed by the following equation (1).
s (t) = d (t) (×) M ₁ (T) (1)
When the noise signal n (t) is added to the spread spectrum signal s (t), the result is as shown in FIG. At this time, the relationship between the spread spectrum signal s (t) and the noise signal n (t) is given by the following equation (2).
s (t) = d (t) (×) M ₁ (T) + n (t) (2)
However, the spread signal M ₁ (T) is 1023 bits long and has a bit rate of 1.023 MHz.
[0004]
Here, for example, when receiving the spread spectrum signal s (t) given by the above equation (2), the GPS receiver performs a demodulation process on the spread spectrum signal s (t). The demodulated signal d ′ (t) demodulated from the spread spectrum signal s (t) can be expressed by the following equation (3).
d ′ (t) = s (t) (×) M ₁ (T)
= D (t) (x) M ₁ (T) (x) M ₁ (T)
+ N (t) (x) M ₁ (T) (3)
At this time, M ₁ (T) (x) M ₁ When (t) = 1, the demodulated signal d ′ (t) is given by the following equation (4).
d ′ (t) = d (t) + n (t) (×) M ₁ (T) ... (4)
In the above equation (4), d (t) is a restored data signal, and n (t) (×) M ₁ (T) is a noise-spread signal n (t).
[0005]
As described above, in the spread spectrum method, the original data signal can be extracted from the spread spectrum signal by appropriately performing spreading / despreading on the data signal. At this time, since the noise signal is spread, The influence can be reduced.
FIG. 7 is a graph showing the relationship between the reception sensitivity of the GPS receiver and the frequency of the noise signal. FIG. 7 shows the relationship in the case where only a noise signal composed of a single frequency component as described above exists. As shown in the figure, as the frequency component of the noise signal detunes from the center frequency fo of the signal to be received by the GPS receiver, the reception sensitivity of the signal to be received becomes higher, and the frequency component of the noise signal becomes higher. Is the lowest when the frequency coincides with the center frequency fo of the signal to be received.
[0006]
Further, when a relationship such as the following equation (5) is given to the spread signal, the data signal can be selected by the spread signal (spread code). This is CDMA (Code Division Multiple Access). In the case of GPS, a different code (spread signal) is used for each GPS satellite.
M _n (T) (x) M _m (T) ≈0 (n ≠ m) or = 1 (n = M) (5)
[0007]
Here, the noise signal n of two frequency components ₁ (T), n ₂ Considering the case where (t) exists, the demodulated signal d ′ (t) can be expressed by the following equation (6) from the above equations (2) and (4).
d ′ (t) = d (t) + {n ₁ (T) + n ₂ (T)}
(×)) M ₁ (T) ... (6)
As can be seen from this equation (6), the sum of the reception levels of the noise signal is one of the factors that affect the reception quality of the GPS receiver.
Thus, the influence of the noise signal on the reception sensitivity of the spread spectrum signal depends on the sum of the reception levels of the noise signal shown in the above equation (6) and the frequency (frequency characteristic) of the noise signal shown in FIG. It is determined.
[0008]
Conventionally, the evaluation of the influence of the noise signal as described above on the reception performance of the GPS receiving apparatus has been made by actually causing the GPS receiving apparatus to receive the GPS signal, and evaluating the influence of the noise signal from the reception status at that time.
[0009]
[Problems to be solved by the invention]
Since the conventional noise evaluation method is performed as described above, in order to reduce the influence of the position change due to the orbit of the GPS satellite (average), not only a long-time measurement is required, but also the position with the GPS satellite is required. Since the evaluation result is greatly influenced by the relationship, there is a problem that the evaluation result may differ depending on the time zone of the day of measurement.
[0010]
Also, since the spread spectrum method is used, the noise signal that is received at the time of reception is spread over a wide band by despreading. Therefore, when there are a plurality of noise signals having different frequencies, GPS signals are generated by these noise signals. There is a problem in that it is impossible to estimate how much the reception sensitivity of the receiving apparatus is affected, and it is impossible to uniquely determine the allowable value of the reception level of the noise signal.
[0011]
The above problem will be specifically described.
FIG. 8 is a diagram showing a pattern of a noise signal generated upon reception of a GPS signal. FIG. 8A shows a case where the reception level of a noise signal having a frequency close to the center frequency of the GPS signal to be received is high. ) Shows a case where the reception level of a noise signal having a frequency close to the center frequency of the GPS signal to be received is small. In the figure, the noise signal n shown in FIGS. 8 (a) and 8 (b). ₁ (T), n ₂ When the sum of the reception levels of (t) is equal, the noise signal n is determined by the conventional noise evaluation method. ₁ (T), n ₂ The effect of (t) on the reception sensitivity of the GPS receiver cannot be distinguished.
However, as shown in FIG. 7, in an actual reception environment, a noise signal n having a frequency close to the center frequency fo of the GPS signal to be received. ₁ As the reception level of (t) is larger, the GPS signal reception sensitivity is degraded.
As described above, in the conventional noise evaluation method, it is impossible to estimate how much the reception sensitivity of the GPS receiver is affected by the noise signal, and it is possible to uniquely determine the allowable value of the reception level of the noise signal. could not.
[0012]
The present invention has been made to solve the above-described problems, and is a detuning frequency from the center frequency of a signal to be received with respect to a reception level of a noise signal that is received when a spread spectrum signal is received. An object of the present invention is to obtain a noise evaluation method capable of performing accurate and quantitative noise evaluation by weighting according to the above.
[0013]
Another object of the present invention is to obtain a noise evaluation apparatus that implements the noise evaluation method.
[0014]
Furthermore, it aims at obtaining the electronic device and vehicle which evaluated the influence by the noise signal given to a GPS receiver using the said noise evaluation method.
[0015]
It is another object of the present invention to obtain a GPS receiver arrangement method for obtaining a relative distance between an electronic device and a GPS receiver that optimizes the reception performance of the GPS receiver using the noise evaluation method.
[0016]
Furthermore, the electronic device arranged at a position satisfying the relative distance obtained by the arrangement method of the GPS receiver, and the GPS receiver and the electronic device at a position satisfying the relative distance obtained by the arrangement method of the GPS receiver. The purpose is to obtain a vehicle in which and are arranged.
[0017]
[Means for Solving the Problems]
The noise evaluation method according to the present invention includes a noise extraction step for obtaining a frequency and a reception level of a noise signal included in a frequency band of a spread spectrum signal obtained by performing spread spectrum on a signal to be received, and a signal to be received with respect to the noise signal. A noise suppression weighting step for adding a reception level weighting according to a detuning frequency from the center frequency of the noise, and a noise summation value calculating step for calculating a summation value of the reception level of the noise signal weighted in the noise suppression weighting step; The noise signal reception level total value calculated in the noise total value calculation step is compared with a predetermined standard value to evaluate whether the reception level of the noise signal is acceptable in the reception of the spread spectrum signal. A noise evaluation step.
[0018]
The noise evaluation method according to the present invention includes a noise extraction step for obtaining a frequency and a reception level of a noise signal included in a frequency band of a spread spectrum signal obtained by performing spread spectrum on a signal to be received, and a signal to be received with respect to the noise signal. The reception level corresponding to the detuning frequency from the center frequency of the signal is calculated, and the standard value of the reception level corresponding to the number of noise signal peaks for each detuning frequency from the center frequency of the signal to be received is set in advance. And a noise evaluation step for evaluating whether or not the reception level of the noise signal is acceptable in the reception of the spread spectrum signal.
[0019]
The noise evaluation method according to the present invention is used for GPS (Global Positioning System).
[0020]
The noise evaluation apparatus according to the present invention includes a noise extraction unit that obtains a frequency and a reception level of a noise signal included in a frequency band of a spread spectrum signal obtained by performing spread spectrum on a signal to be received, and a signal to be received with respect to the noise signal. Noise suppression weighting means for weighting the reception level according to the detuning frequency from the center frequency of the noise, and noise sum value calculation means for calculating the sum of the reception levels of the noise signals weighted by the noise suppression weighting means; The noise signal reception level calculated by the noise total value calculation means is compared with a predetermined standard value to evaluate whether or not the reception level of the noise signal is acceptable in the reception of the spread spectrum signal. Noise evaluation means.
[0021]
The noise evaluation apparatus according to the present invention includes a noise extraction means for obtaining a frequency and a reception level of a noise signal included in a frequency band of a spread spectrum signal obtained by performing a spread spectrum of the signal to be received, and a center frequency of the signal to be received. Standard value storage means for storing the standard value of the reception level corresponding to the number of peaks of the noise signal for each detuning frequency, and the center frequency of the signal to be received with respect to the noise signal for which the noise extraction means has determined the frequency and reception level Calculate the reception level according to the detuning frequency from the signal, and the standard value of the reception level according to the number of noise signal peaks for each detuning frequency from the center frequency of the signal to be received stored in the standard value storage means And a noise evaluation means for evaluating whether or not the reception level of the noise signal is acceptable in the reception of the spread spectrum signal. It is obtain things.
[0022]
The noise evaluation apparatus according to the present invention is used for GPS.
[0023]
The GPS receiver arrangement method according to the present invention is arranged with a predetermined distance away from an electronic device that can be a noise generation source, and for a GPS receiver that receives a spectrum spread signal obtained by spectrum-spreading a signal in the GPS band, A noise evaluation step for evaluating the reception level of a noise signal received in addition to the spread spectrum signal using the noise evaluation method, and the reception level of the noise signal evaluated in the noise evaluation step is acceptable for reception of the spread spectrum signal. When the distance is not within the possible range, the distance change step for changing the predetermined distance between the GPS receiver and the electronic device, and the reception level of the noise signal obtained as a result of the change in the distance change step is A predetermined distance within the allowable range is used to optimize the reception performance of the GPS receiver. In which and a relative distance determination step of determining a relative distance between the device and the GPS receiver.
[0024]
The GPS receiver arrangement method according to the present invention is the above-described noise evaluation method for a GPS receiver that is mounted on a vehicle together with an electronic device that can be a noise generation source and that receives a spread spectrum signal obtained by spectrum-spreading a GPS band signal. A noise evaluation step for evaluating the reception level of the received noise signal in addition to the spread spectrum signal using the noise level, and the reception level of the noise signal evaluated in the noise evaluation step is within an allowable range for reception of the spread spectrum signal. When there is not, the distance change step for changing the relative distance between the GPS receiver and the electronic device, and as a result of the change at this distance change step, the reception level of the noise signal becomes an allowable range in the reception of the spread spectrum signal Once the relative distance is obtained, the GPS receiver can be In which and a placement step of placing the child device in the vehicle.
[0025]
The electronic device according to the present invention is characterized in that the reception level of a noise signal applied to a GPS receiver that receives a spread spectrum signal obtained by performing spectrum spread on a GPS band signal using the noise evaluation method is evaluated. is there.
[0026]
The vehicle according to the present invention includes a GPS receiver that receives a spread spectrum signal obtained by spectrum-spreading a signal in the GPS band, together with an electronic device that can be a noise generation source, and the electronic device is a GPS receiver using the noise evaluation method. The reception level of the noise signal given to the device is evaluated.
[0027]
In the electronic device according to the present invention, the reception level of the noise signal given to the GPS receiver that receives the spread spectrum signal obtained by performing the spectrum spread of the GPS band signal by using the above-described GPS receiver arrangement method is acceptable in receiving the spread spectrum signal. It is characterized in that a relative distance in a possible range is obtained and arranged at a position that satisfies this relative distance.
[0028]
The vehicle according to the present invention includes a GPS receiver that receives a spread spectrum signal obtained by spectrum-spreading a signal in the GPS band using the GPS receiver arrangement method, and an electronic device that can be a noise source.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below.
Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of a noise evaluation apparatus according to Embodiment 1 of the present invention. In the figure, reference numeral 1 denotes an anechoic chamber for performing noise evaluation, which is shielded from electromagnetic waves from the outside in order to accurately measure and evaluate noise from electronic equipment in the vehicle 2. 2 is a vehicle equipped with a GPS receiver together with electronic equipment that can be a noise generation source, 3 is a GPS antenna (GPS receiver) that receives radio waves from a GPS satellite (not shown), and 4 is supplied with power to the GPS antenna 3 Bias tees 5a and 5b are amplifiers for amplifying the GPS signals received by the GPS antenna 3 from the GPS satellites, 6 is a power circuit for an amplifier for supplying power to the amplifiers 5a and 5b, and 7 is a GPS received by the GPS antenna 3. A spectrum analyzer (noise extraction means) that analyzes the frequency of the signal extracts a noise signal included in the frequency band of the received GPS signal, and obtains the frequency and reception level. 7A is a control device (noise suppression weighting means, noise sum value calculation means, noise evaluation means) according to the detuning frequency from the center frequency of the GPS signal with respect to the reception level of the noise signal extracted by the spectrum analyzer 7. Whether the received signal level of the noise signal is acceptable in the reception of the spread spectrum signal by calculating the total value of the received signal level of the weighted noise signal and comparing it with a predetermined standard value. To evaluate. The control device 7A can be realized by a computer system that stores a program for executing the above operation.
[0030]
Next, the operation will be described.
First, the GPS signal received by the GPS antenna 3 is measured by the spectrum analyzer 7 via the bias tee 4 and the amplifiers 5a and 5b, and the frequency and reception level of the spurious noise included in the frequency band of the spread spectrum signal of the GPS signal are measured. Obtain (noise extraction step).
Specifically, for example, the following spectrum analyzer 7 is set for a GPS signal having a wide band due to spectrum spreading.
In narrow band measurement of the spectrum analyzer 7, the center frequency fo of the GPS signal is 1.57542 GHz, the measurement span is 2.0 MHz, the RBW is 3.0 kHz, the VBW is 3.0 kHz, the scanning time is 560 ms, and the level of the received signal is Every 5 dB (5 dB / DIV) is displayed, and the offset (including cable loss) is the absolute gain G of the GPS antenna 3 _A (DBi) and the gain G of the amplifiers 5a and 5b _B Sum G _A + G _B Set as (dB). In the broadband measurement of the spectrum analyzer 7, the center frequency fo of the GPS signal is 1.57542 GHz, the measurement span is 10 MHz, the RBW is 10 kHz, the VBW is 10 kHz, the scanning time is 560 ms, and the level of the received signal is every 5 dB (5 dB). / DIV) and the offset (including cable loss) is the absolute gain G of the GPS antenna 3 _A (DBi) and the gain G of the amplifiers 5a and 5b _B Sum G _A + G _B Set as (dB).
[0031]
Next, the control device 7A adds weighting of the reception level according to the detuning frequency from the center frequency of the GPS signal to be received to the spurious noise whose frequency and reception level are obtained by the spectrum analyzer 7 (noise suppression weighting step). ).
Specifically, according to the following formula (7), the reception level is weighted according to the detuning frequency from the center frequency fo of the GPS signal to be received.
U ' _n (Δf) = U _n (Δf) − {T (Δf) + A} (7)
However, U ' _n (Δf) is a noise reception level to which weighting according to the detuning frequency Δf from the center frequency fo of the GPS signal is added. _n (Δf) is a reception level of noise detuned from the center frequency fo of the GPS signal by a frequency Δf, and T (Δf) is a weighting of the reception level according to the detuning frequency from the center frequency fo of the GPS signal. It is given by the following formula (8).
(1) When Δf ≦ ± 0.5MHz
T (Δf) = − A (dBμV)
(2) When ± 0.5 ≤ Δf ≤ ± 2.0 MHz
T (Δf) = − A + 20 × (| Δf | −0.5) (dBμV)
(3) When Δf ≧ ± 2.0 MHz
T (Δf) = − A + 30 (dBμV) (8)
n is the number of noise peaks for each detuning frequency Δf from the center frequency fo of the GPS signal. B is an increase in base noise (dBμV), and power is applied to the electronic device in the vehicle 2 from the dark noise level generated in the GPS receiver or measuring device separately from the noise in receiving the GPS signal. The increase in the noise that becomes the base that has been raised in is shown.
[0032]
Further, the number n of noise peaks for each detuning frequency Δf from the center frequency fo of the GPS signal described above does not simply indicate the number of noise pulse peaks. FIG. 2 is a diagram illustrating an example of noise having a bandwidth. As shown in the figure, in the case of broadband noise, the noise evaluation apparatus according to the first embodiment also includes the number of sample values corresponding to spurious noise among the reception levels sampled by the spectrum analyzer 7 for each frequency of the measurement span. , And the noise peak number n for each detuning frequency Δf from the center frequency fo of the GPS signal. In the example shown in the figure, since the noise is a wide band, sampling is performed five times for each frequency of the measurement span. In this case, it is assumed that there are five peak noises.
[0033]
Furthermore, in the above equation (7), the reception level of the spurious noise GPS signal when the detuning frequency Δf is 0 is set to −AdB μV, for example, so that the influence of the spurious noise when the detuning frequency Δf is 0 is maximized. Yes. As a result, when T (Δf) in − {T (Δf) + A} of the second item on the right side of Equation (7) becomes −AdB μV, − {T (Δf) + A} = 0 and U ′ _n The noise reception level indicated by (Δf) becomes the maximum value.
[0034]
As described above, when weighting is applied to the reception level of each spurious noise that is detuned from the center frequency fo of the GPS signal by the frequency Δf, the sum of the reception levels of each spurious noise to which the control device 7A has added the weight. A value is calculated (noise total value calculation step).
Specifically, the sum value of the reception levels of each spurious noise is calculated according to the following equation (9).
[Expression 1]

[0035]
Finally, the control device 7A compares the sum of reception levels of spurious noises calculated according to the above equation (9) with a predetermined standard value. Here, the predetermined standard value is, for example, −AdB μV. As a result of the comparison, if the sum of the reception levels of spurious noise is equal to or less than a predetermined standard value −AdB μV, the control device 7A determines that the reception level of the spurious noise has no problem with the reception performance of the GPS receiver, If it is equal to or greater than a predetermined standard value, it is determined that the reception performance of the GPS receiver is not within an allowable range (noise evaluation step).
[0036]
As described above, if it is determined that the reception performance of the GPS receiver is not within the allowable range due to spurious noise, an electronic device (not shown) that can be a noise generation source mounted in the vehicle 2, the GPS antenna 3, and the like The relative distance from the GPS receiving device constituted by is changed (distance changing step). The relative distance mentioned here may be changed with reference to either the GPS receiver or the electronic device (that is, either the GPS receiver or the electronic device is fixed and the other is moved). The selection of the fixed side and the moving side is appropriately performed in the vehicle 2).
[0037]
The frequency of spurious noise included in the frequency band of the spread spectrum signal of the GPS signal by the spectrum analyzer 7 described above every time the relative distance between the electronic device (not shown) and the GPS receiving device including the GPS antenna 3 is changed. The operation from the measurement of the reception level to the evaluation of the spurious noise by the control device 7A is repeated until the reception level of the spurious noise is determined to be an allowable range in the reception of the spread spectrum signal.
[0038]
When the reception level of the spurious noise falls within an allowable range in the reception of the spread spectrum signal due to the noise evaluation, the control device 7A determines the relative distance between the electronic device and the GPS reception device at this time and the reception performance of the GPS reception device. Decide what you want to optimize. The electronic device and the GPS receiver are arranged in the vehicle 2 so as to satisfy the relative distance between the optimized electronic device and the GPS receiver by the control device 7A (arrangement step).
In this way, the vehicle in which the electronic device and the GPS receiver are arranged so as to satisfy the relative distance determined by the control device 7A is quantitatively evaluated for spurious noise in GPS reception, and this influence is minimal. Is suppressed.
[0039]
As described above, according to the first embodiment, the frequency and reception level of the noise signal included in the frequency band of the spread spectrum signal obtained by performing spectrum spreading on the GPS signal to be received are obtained, and reception is performed on this noise signal. The weight of the reception level corresponding to the detuning frequency from the center frequency of the signal to be added is added, and the sum of the reception levels of the noise signal to which this weight is added is calculated and compared with a predetermined standard value. Since it is evaluated whether or not the reception level of the noise signal is acceptable in signal reception, noise that interferes with the reception performance of the GPS band can be defined quantitatively.
[0040]
Further, according to the first embodiment, the above-described GPS receiver is mounted on the vehicle 2 together with an electronic device that can be a noise generation source, and includes a GPS antenna 3 that receives a spread spectrum signal in the GPS band. The reception level of the received noise signal in addition to the spread spectrum signal is evaluated using the noise evaluation method shown in the first embodiment, and the received level of the evaluated noise signal is within an allowable range in receiving the spread spectrum signal. If the relative distance between the GPS receiver and the electronic device is changed, and as a result of this change, the relative distance at which the reception level of the noise signal is within an acceptable range in reception of the spread spectrum signal is obtained, Since the GPS receiver and the electronic device are arranged in the vehicle 2 so as to satisfy this relative distance, an electronic device that can be a noise generation source The GPS receiving device composed of the GPS antenna 3 and the like can be disposed at a position where the influence of the noise of the GPS band is minimized, and the vehicle 2 having excellent GPS band receiving performance can be provided. .
[0041]
Embodiment 2. FIG.
In the control device 7A of the noise evaluation device that realizes the noise evaluation method according to the second embodiment, the standard value of the reception level according to the number of spurious noise peaks for each detuning frequency from the center frequency of the GPS signal to be received is set. A memory (standard value storage means) for storing is provided.
[0042]
Next, the operation will be described.
Also in the second embodiment, as in the first embodiment, the evaluation is performed on the vehicle 2 equipped with the GPS receiver together with the configuration shown in FIG. Will be described.
First, the GPS signal received by the GPS antenna 3 is measured by the spectrum analyzer 7 via the bias tee 4 and the amplifiers 5a and 5b, and the frequency and reception level of the spurious noise included in the frequency band of the spread spectrum signal of the GPS signal are measured. Obtain (noise extraction step). The operation up to this point is the same as in the first embodiment.
[0043]
Next, the control device 7A calculates a reception level corresponding to the detuning frequency from the center frequency of the GPS signal to be received with respect to the spurious noise whose frequency and reception level are obtained by the spectrum analyzer 7, and stores this in the memory. The standard value of the reception level corresponding to the number of spurious noise peaks for each detuning frequency from the center frequency of the stored GPS signal is compared.
Specifically, for example, a standard value of an allowable reception level of spurious noise in the GPS band as shown in FIG. 3 is set in advance in the memory. This standard value is calculated by substituting the detuning frequency from the center frequency of the GPS signal and the number of noise peaks at that time into the following equation (10).
T (Δf) +10 log (1 / n) −B (10)
Also, the numbers of noise peaks indicated by the black square symbol plot, the black triangle symbol plot, the x symbol plot, and the black circle symbol plot in FIG. 3 are 2, 3, and 5, respectively. The relationship of 10 is also calculated using the above equation (10).
[0044]
If the spurious noise corresponding to the detuning frequency Δf from the center frequency of the GPS signal is equal to or less than the standard value shown in FIG. 3 by the comparison operation described above, the control device 7A has no problem with the reception performance of the GPS receiving device. If it is equal to or higher than the above standard value, it is determined that the reception performance of the GPS receiver is not within the allowable range (noise evaluation step).
Here, when it is determined that the spurious noise is not within the allowable range in the reception performance of the GPS receiver, the spurious noise in the GPS band is measured again, and noise evaluation is performed using the noise evaluation method described in the first embodiment. I do.
[0045]
Also in the noise evaluation method shown in the first embodiment, when it is determined that the measured spurious noise is not within the allowable range in the reception performance of the GPS receiver, the noise generation source mounted in the vehicle 2 The relative distance between an electronic device (not shown) that can be a GPS receiver and the GPS antenna 3 is changed (distance changing step). As in the first embodiment, the relative distance changing operation may be changed by moving either the GPS receiver or the electronic device while fixing the arrangement location of the GPS receiver or the electronic device. Is appropriately selected in the vehicle 2.
[0046]
The frequency of spurious noise included in the frequency band of the spread spectrum signal of the GPS signal by the spectrum analyzer 7 described above every time the relative distance between the electronic device (not shown) and the GPS receiving device including the GPS antenna 3 is changed. The operation from the measurement of the reception level to the evaluation of the spurious noise by the control device 7A is repeated until the reception level of the spurious noise is determined to be an allowable range in the reception of the spread spectrum signal.
[0047]
When the reception level of the spurious noise falls within an allowable range in the reception of the spread spectrum signal due to the noise evaluation, the control device 7A determines the relative distance between the electronic device and the GPS reception device at this time and the reception performance of the GPS reception device. Decide what you want to optimize. The electronic device and the GPS receiver are arranged in the vehicle 2 so as to satisfy the relative distance between the optimized electronic device and the GPS receiver by the control device 7A (arrangement step).
In this way, the vehicle in which the electronic device and the GPS receiver are arranged so as to satisfy the relative distance determined by the control device 7A is quantitatively evaluated for spurious noise in GPS reception, and this influence is minimal. Is suppressed.
[0048]
As described above, according to the second embodiment, the frequency and reception level of the noise signal included in the frequency band of the spread spectrum signal obtained by performing spectrum spreading on the GPS signal to be received are obtained, and reception is performed on this noise signal. The reception level corresponding to the detuning frequency from the center frequency of the signal to be calculated is calculated, and the reception level corresponding to the number of noise signal peaks for each detuning frequency from the center frequency of the signal to be received is set in advance. Since it is compared with the standard value and it is evaluated whether or not the reception level of the noise signal is acceptable in the reception of the spread spectrum signal, the same effect as in the first embodiment can be obtained.
[0049]
Further, according to the second embodiment, the above-described GPS receiver is mounted on the vehicle 2 together with an electronic device that can be a noise generation source, and includes a GPS antenna 3 that receives a spread spectrum signal in the GPS band. The reception level of the noise signal received in addition to the spread spectrum signal is evaluated using the noise evaluation method shown in the second embodiment, and the received level of the evaluated noise signal is within an allowable range in reception of the spread spectrum signal. If the relative distance between the GPS receiver and the electronic device is changed, and as a result of this change, the relative distance at which the reception level of the noise signal is within an acceptable range in reception of the spread spectrum signal is obtained, Since the GPS receiver and the electronic device are arranged in the vehicle 2 so as to satisfy this relative distance, an electronic device that can be a noise generation source The GPS receiving device composed of the GPS antenna 3 and the like can be disposed at a position where the influence of the noise of the GPS band is minimized, and the vehicle 2 having excellent GPS band receiving performance can be provided. .
[0050]
The vehicle 2 shown in the first embodiment or the second embodiment is equipped with a GPS receiver that receives a spread spectrum signal in the GPS band together with an electronic device that can be a noise generation source. Alternatively, since the reception level of spurious noise given to the GPS receiver by the electronic device is evaluated using the noise evaluation method shown in the second embodiment, noise that interferes with GPS band reception performance is quantitatively defined. Therefore, it can be used as an index of noise influence when the reception performance of the GPS band is improved.
[0051]
Furthermore, the vehicle 2 shown in the first embodiment or the second embodiment is used as a GPS receiver that receives a spread spectrum signal in the GPS band as shown in the first embodiment or the second embodiment. Since a relative distance in which the received level of the noise signal to be given is within an allowable range in the reception of the spread spectrum signal is obtained, and the electronic device and the GPS receiver are arranged at a position satisfying the relative distance, the reception of the GPS band is performed. Excellent performance.
[0052]
Embodiment 3 FIG.
4 is a diagram showing a configuration of a noise evaluation apparatus according to Embodiment 3 of the present invention, and FIG. 5 is a top view of FIG. In the figure, reference numeral 7B denotes a control device (noise suppression weighting means, noise sum value calculation means, noise evaluation means), which is basically extracted by the spectrum analyzer 7 in the same manner as the control device 7A of the first embodiment. Add the weight of the reception level according to the detuning frequency from the center frequency of the GPS signal to the reception level of the noise signal, calculate the total value of the reception level of the weighted noise signal and compare it with the predetermined standard value Then, it is evaluated whether or not the reception level of the allowable noise signal in receiving the spread spectrum signal. The control device 7B can be realized by a computer system that stores a program for executing the above operation. Reference numeral 8 denotes an electronic device that is the object of noise evaluation, and 9 is a polystyrene base on which the electronic device 8 is installed. The height of the opening center of the horn antenna 13 and the electronic device 8 is matched, and the electronic device 8 is connected to the ground plane 10. Electrically shut off. Reference numeral 10 denotes a ground plane installed on the upper surface of the measuring table 11, and 11 denotes a measuring table, which keeps the height from the ground plane 10 to the ground 12 to 1 m.
[0053]
Reference numeral 13 denotes a horn antenna (GPS receiver) that receives noise from the electronic device 8, and reference numeral 13a denotes a support bar (GPS receiver) on which the horn antenna 13 is installed. Further, the distance L from the opening of the horn antenna 13 to the electronic device 8 is determined by the type of the electronic device 8 and the normal installation site. For example, if the electronic device 8 is installed in the immediate vicinity of the GPS antenna 3, it is determined as appropriate in consultation with the measurer. If the electronic device 8 is installed in the passenger compartment, the distance L is 25 cm. If it is installed outside the passenger compartment, the distance L is set to 100 cm. A power circuit 14 supplies power to the electronic device 8. In addition, the same code | symbol is attached | subjected to the same component as FIG. 1, and the overlapping description is abbreviate | omitted.
[0054]
Next, the operation will be described.
First, the spurious noise in the GPS band received by the horn antenna 13 is measured by the spectrum analyzer 7 through the amplifiers 5a and 5b, and the frequency and reception level of the spurious noise are obtained (noise extraction step).
Specifically, for example, the following spectrum analyzer 7 is set for a GPS signal having a wide band due to spectrum spreading.
In narrow band measurement of the spectrum analyzer 7, the center frequency fo of the GPS signal is 1.57542 GHz, the measurement span is 2.0 MHz, the RBW is 3.0 kHz, the VBW is 3.0 kHz, the scanning time is 560 ms, and the level of the received signal is Every 5 dB (5 dB / DIV) is displayed, and the offset is the absolute gain G of the horn antenna 13 _A (DBi) and the gain G of the amplifiers 5a and 5b _B Sum G _A + G _B Set as (dB). In the broadband measurement of the spectrum analyzer 7, the center frequency fo of the GPS signal is 1.57542 GHz, the measurement span is 10 MHz, the RBW is 10 kHz, the VBW is 10 kHz, the scanning time is 560 ms, and the level of the received signal is every 5 dB (5 dB). / DIV), and the offset is the absolute gain G of the horn antenna 13. _A (DBi) and the gain G of the amplifiers 5a and 5b _B Sum G _A + G _B Set as (dB).
[0055]
Also, the overall gain value G of the horn antenna 13 _A Includes the loss in the cable connecting the power supply circuit 14 and the horn antenna 13. Further, the horn antenna 13 is installed on the support rod 13a via a rotation drive circuit (not shown) so that the horn antenna 13 can be rotated about the opening center thereof. This is because the shape of the opening of the horn antenna 13 is rectangular and the length is different between the horizontal direction and the vertical direction. For example, after measuring at the position where the long side of the opening is in the horizontal direction, it is rotated to the horizontal direction. Measurement is performed after the position where the short side of the opening comes to the position.
[0056]
Next, the control device 7B adds the weight of the reception level corresponding to the detuning frequency from the center frequency of the GPS signal to be received to the spurious noise whose frequency and reception level are obtained by the spectrum analyzer 7 (noise suppression weighting step). ).
[0057]
Also in the third embodiment, the number of noise peaks n for each detuning frequency Δf from the center frequency fo of the GPS signal described above does not simply indicate the number of noise pulse peaks, but the embodiment described above. 2, in the case of broadband noise as shown in FIG. 2, the number of sample values corresponding to spurious noise among the reception levels sampled by the spectrum analyzer 7 for each frequency of the measurement span is also the center of the GPS signal. It is assumed that it is included in the number of noise peaks n for each detuning frequency Δf from the frequency fo.
[0058]
As described above, when weighting is applied to the reception level of each spurious noise that is detuned from the center frequency fo of the GPS signal by the frequency Δf, the sum of the reception levels of each spurious noise to which the control device 7B has added the weight. A value is calculated (noise total value calculation step). Specifically, as in the first embodiment, the sum value of the reception levels of each spurious noise is calculated according to the above equation (9).
[0059]
Finally, the control device 7B compares the sum of the reception levels of the spurious noises calculated according to the above equation (9) with a predetermined standard value. As a result of the comparison, if the sum of the reception levels of spurious noise is equal to or less than a predetermined standard value, the control device 7B is an electronic device 8 that generates spurious noise at a reception level that has no problem with the reception performance of the GPS receiver. If it is equal to or greater than a predetermined standard value, it is determined that the electronic device 8 generates spurious noise having a reception level that is not within an allowable range in the reception performance of the GPS receiver (noise evaluation step).
[0060]
As described above, when it is determined that the electronic device 8 generates spurious noise having a reception level that is not within the allowable range in the reception performance of the GPS receiver, the distance L between the electronic device 8 and the opening of the horn antenna 13 is determined. Is changed (distance change step).
[0061]
Each time the distance L between the electronic device 8 and the opening of the horn antenna 13 is changed, the frequency of the GPS band spurious noise and the reception level from the electronic device 8 described above are measured by the spectrum analyzer 7 and the spurious noise by the control device 7B. The operation up to the evaluation is repeated until it is determined that the reception level of spurious noise is within an allowable range in reception of the spread spectrum signal.
[0062]
When the reception level of the spurious noise falls within an allowable range for reception of the spread spectrum signal by the noise evaluation, the control device 7B determines the distance L between the electronic device 8 and the opening of the horn antenna 13 at this time. The reception performance is determined to be optimized (relative distance determination step). The electronic device and the GPS receiver are arranged in the vehicle 2 so as to satisfy the distance L between the optimized electronic device and the opening of the horn antenna 13 by the control device 7B (arrangement step).
Thus, in a vehicle in which the electronic device and the GPS receiver are arranged so as to satisfy the relative distance determined by the control device 7B, spurious noise in GPS reception is quantitatively evaluated, and this influence is minimal. Is suppressed.
[0063]
The second embodiment can also be applied to the third embodiment. In this case, the control device 7B is provided with a memory (standard value storage means) for storing a standard value of the reception level corresponding to the number of spurious noise peaks for each detuning frequency from the center frequency of the GPS signal to be received.
[0064]
Next, the operation will be described.
Similarly to the above, the frequency and reception level of the spurious noise in the GPS band generated by the electronic device 8 are measured by the spectrum analyzer 7 via the amplifiers 5a and 5b (noise extraction step).
Next, the control device 7B calculates the reception level corresponding to the detuning frequency from the center frequency of the GPS signal to be received with respect to the spurious noise whose frequency and reception level are obtained by the spectrum analyzer 7, and stores this in the memory. The standard value of the reception level corresponding to the number of spurious noise peaks for each detuning frequency from the center frequency of the stored GPS signal is compared.
Specifically, as in the second embodiment, for example, a standard value of an allowable reception level of spurious noise in the GPS band as shown in FIG. 3 is set in advance in the memory.
[0065]
If the spurious noise corresponding to the detuning frequency Δf from the center frequency of the GPS signal is equal to or less than the standard value shown in FIG. 3 by the comparison operation described above, the control device 7B has a reception level that does not cause a problem in the reception performance of the GPS receiver. It is determined that the electronic device 8 generates spurious noise, and if it is equal to or higher than the standard value, it is determined that the electronic device 8 generates spurious noise having a reception level not within the allowable range in the reception performance of the GPS receiver. (Noise evaluation step).
Here, when it is determined that the spurious noise is not within the allowable range in the reception performance of the GPS receiver, the spurious noise in the GPS band is measured again, and noise evaluation is performed using the noise evaluation method described in the first embodiment. I do.
Since the subsequent operation is the same as that of the above embodiment, a duplicate description is omitted.
[0066]
As described above, according to the third embodiment, the horn antenna 13 that receives the spread spectrum signal that is arranged by a predetermined distance away from the electronic device 8 that can be a noise generation source and that spreads the signal of the GPS band. On the other hand, the reception level of the noise signal received in addition to the spread spectrum signal is evaluated using the noise evaluation method described in the first embodiment or the second embodiment, and the received level of the evaluated noise signal is the spectrum. When the spread signal reception is not within the allowable range, the predetermined distance between the GPS receiver and the electronic device is changed. As a result of this change, the reception level of the noise signal is changed to the allowable range for reception of the spread spectrum signal. When a predetermined distance is obtained, the relative distance between the GPS receiver and the electronic device that optimizes the reception performance of the GPS receiver Since determined, it is possible to provide a relative distance is an index to determine the installation position of the GPS receiver with reduced influence of spurious noise in GPS band from the electronic device 8 which can be a noise source.
[0067]
Further, the electronic device 8 shown in the third embodiment gives a GPS receiving device including a horn antenna 13 that receives a spread spectrum signal in the GPS band using the noise evaluation method shown in the first to third embodiments. Since the reception level of the noise signal is evaluated, noise that interferes with the reception performance of the GPS band is quantitatively defined, and can be used as an index of noise influence when mounted on a vehicle or the like.
[0068]
Furthermore, as shown in the above embodiment, the electronic device 8 shown in the third embodiment has a reception level of a noise signal applied to a GPS receiver including a horn antenna 13 that receives a spread spectrum signal in the GPS band. The relative distance that is within an acceptable range for receiving the spread spectrum signal is obtained and placed at a position that satisfies this relative distance, so that it is possible to reduce the influence of self-generated noise on the GPS receiver. The reception performance of the GPS band can be optimized.
[0069]
Furthermore, since the noise evaluation method and the noise evaluation apparatus according to the first to third embodiments are used for GPS (Global Positioning System), it is possible to quantitatively define the noise in the GPS employing the spread spectrum method.
[0070]
【The invention's effect】
As described above, according to the present invention, the noise extraction step for obtaining the frequency and reception level of the noise signal included in the frequency band of the spread spectrum signal obtained by performing spread spectrum on the signal to be received, and receiving the noise signal A noise suppression weighting step that adds weighting of the reception level according to the detuning frequency from the center frequency of the power signal, and a noise sum value calculation that calculates the sum value of the reception level of the noise signal weighted in this noise suppression weighting step Comparing the sum of the reception level of the noise signal calculated in the step and the noise total value calculation step with a predetermined standard value to determine whether or not the reception level of the noise signal is acceptable in the reception of the spread spectrum signal. And a noise evaluation step for evaluating the spectrum. There is an effect that can be defined quantitatively noise signals disturb the reception performance of the frequency band of the Le spread signal.
[0071]
According to the present invention, the noise extraction step for obtaining the frequency and reception level of the noise signal included in the frequency band of the spread spectrum signal obtained by performing spectrum spreading on the signal to be received, and the center frequency of the signal to be received with respect to the noise signal The reception level according to the detuning frequency from the signal is calculated, and this is compared with the standard value of the reception level according to the number of peaks of the noise signal for each detuning frequency from the center frequency of the signal to be received. Thus, the noise evaluation step for evaluating whether or not the reception level of the allowable noise signal in the reception of the spread spectrum signal is provided, so that the same effect as in the above paragraph 0070 can be obtained, and the number of peaks of the noise signal can be reduced. There is an effect that an appropriate evaluation value for noise can be provided by using and appropriately changing the standard value.
[0072]
According to the present invention, since it is used for GPS (Global Positioning System), there is an effect that noise in the GPS adopting the spread spectrum method can be defined quantitatively.
[0073]
According to the present invention, the noise extraction means for obtaining the frequency and reception level of the noise signal included in the frequency band of the spread spectrum signal obtained by performing spectrum spreading on the signal to be received, and the center frequency of the signal to be received with respect to the noise signal Noise suppression weighting means for weighting the reception level in accordance with the detuning frequency from the noise, noise summation value calculation means for calculating the summation value of the reception level of the noise signal weighted by the noise suppression weighting means, and noise summation Noise evaluation means for evaluating whether or not the reception level of the noise signal is acceptable in the reception of the spread spectrum signal by comparing the sum of the reception levels of the noise signal calculated by the value calculation means with a predetermined standard value Therefore, the frequency band receivability of a spread spectrum signal obtained by spreading the signal to be received is spread. There is an effect that it is possible to provide a noise evaluation device to define quantitatively the noise signal cause interference on.
[0074]
According to the present invention, the noise extraction means for obtaining the frequency and reception level of the noise signal included in the frequency band of the spread spectrum signal obtained by performing spectrum spreading on the signal to be received, and the detuning frequency from the center frequency of the signal to be received Standard value storage means for storing the standard value of the reception level corresponding to the number of peaks of each noise signal, and the noise signal obtained by the noise extraction means from the center frequency of the signal to be received with respect to the noise signal. Calculate the reception level according to the tuning frequency, and compare this with the standard value of the reception level according to the number of noise signal peaks for each detuning frequency from the center frequency of the signal to be received stored in the standard value storage means And noise evaluation means for evaluating whether or not the reception level of an acceptable noise signal in receiving a spread spectrum signal is provided. It is possible to obtain the same effect as a paragraph 0073.
[0075]
According to this invention, since it is used for GPS, there is an effect that it is possible to provide a noise evaluation apparatus that quantitatively defines noise in GPS that employs a spread spectrum system.
[0076]
According to the present invention, the above-described noise evaluation method is used for a GPS receiver that is arranged at a predetermined distance from an electronic device that can be a noise generation source and receives a spread spectrum signal obtained by performing spread spectrum on a GPS band signal. A noise evaluation step for evaluating the reception level of a noise signal received in addition to the spread spectrum signal, and the reception level of the noise signal evaluated in the noise evaluation step is not within an allowable range for reception of the spread spectrum signal. The distance changing step for changing a predetermined distance between the GPS receiver and the electronic device, and the reception level of the noise signal obtained as a result of the change in the distance changing step is an allowable range for receiving the spread spectrum signal. An electronic device that optimizes the reception performance of the GPS receiver and the GPS receiver with a predetermined distance; And a relative distance determining step that determines the relative distance, so that the relative position is an index for determining the installation position of the GPS receiver in which the influence of the noise signal of the GPS band from the electronic device that can be a noise generation source is reduced. There is an effect that a distance can be provided.
[0077]
According to the present invention, for a GPS receiver that is mounted on a vehicle together with an electronic device that can be a noise generation source and receives a spread spectrum signal obtained by performing spread spectrum on a GPS band signal, the spread spectrum signal is transmitted using the noise evaluation method. A noise evaluation step for evaluating the reception level of the received noise signal, and a GPS reception device when the reception level of the noise signal evaluated in the noise evaluation step is not within an allowable range for reception of the spread spectrum signal A distance change step for changing the relative distance between the electronic device and the electronic device, and a change in the distance change step results in a relative distance at which the reception level of the noise signal is within an acceptable range for reception of the spread spectrum signal. In addition, the GPS receiver and the electronic device are arranged in the vehicle so as to satisfy this relative distance. The GPS receiving device can be placed at a position where the influence of GPS band noise from an electronic device that can be a noise source is minimized, and the GPS band receiving performance is excellent. There is an effect that can be provided.
[0078]
According to the present invention, the reception level of the noise signal given to the GPS receiver that receives the spread spectrum signal obtained by performing the spectrum spread of the GPS band signal using the noise evaluation method is evaluated. The noise signal that interferes with the reception performance is quantitatively defined, and there is an effect that it can be used as an index of noise influence when mounted on a vehicle or the like.
[0079]
According to the present invention, a GPS receiver that receives a spread spectrum signal obtained by spectrum-spreading a GPS band signal is mounted together with an electronic device that can be a noise generation source, and the electronic device is installed in the GPS receiver using the noise evaluation method. Since the noise signal reception level is evaluated, noise that interferes with GPS band reception performance is quantitatively defined, so noise effects when improving GPS band reception performance There is an effect that it can be used as an index.
[0080]
According to the present invention, the reception level of the noise signal given to the GPS receiver that receives the spread spectrum signal obtained by spreading the spectrum of the GPS band signal using the above GPS receiver arrangement method is acceptable in the reception of the spread spectrum signal. Since the relative distance that is the range is obtained and placed at a position that satisfies this relative distance, the influence of the noise signal generated by the device on the GPS receiver can be reduced, and the GPS band can be received. There is an effect that the performance can be optimized.
[0081]
According to the present invention, since the GPS receiver that receives the spread spectrum signal obtained by spectrum-spreading the GPS band signal using the above-described GPS receiver arrangement method and the electronic device that can be a noise generation source are arranged. There is an effect that it is excellent in performance.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a noise evaluation apparatus according to Embodiment 1 of the present invention.
FIG. 2 is a diagram illustrating an example of noise having a bandwidth.
FIG. 3 is a diagram showing a standard value of an allowable reception level of spurious noise in the GPS band.
FIG. 4 is a diagram showing a configuration of a noise evaluation apparatus according to Embodiment 3 of the present invention.
FIG. 5 is a top view of FIG. 4;
FIG. 6 is an explanatory diagram for explaining spread spectrum with respect to a GPS signal.
FIG. 7 is a graph showing the relationship between the reception sensitivity of the GPS receiver and the frequency of the noise signal.
FIG. 8 is a diagram showing a pattern of a noise signal generated when a GPS signal is received.
[Explanation of symbols]
1 Anechoic chamber, 2 vehicles, 3 GPS antenna (GPS receiver), 4 bias tee, 5a, 5b amplifier, 6 power circuit for amplifier, 7 spectrum analyzer (noise extraction means), 7A, 7B control device (noise suppression weighting) Means, noise total value calculation means, evaluation means), 8 electronic equipment, 9 foamed polystyrene table, 10 ground plane, 11 measuring table, 12 ground, 13 horn antenna (GPS receiver), 13a support rod (GPS receiver), 14 Power supply circuit.

Claims (12)

A noise extraction step for obtaining a frequency and a reception level of a noise signal included in a frequency band of a spread spectrum signal obtained by performing spread spectrum on a signal to be received;
A noise suppression weighting step of adding a weight of a reception level according to a detuning frequency from a center frequency of the signal to be received to the noise signal;
A noise sum value calculating step for calculating a sum value of the reception levels of the noise signals weighted in the noise suppression weighting step;
The noise signal reception level calculated in the noise total value calculation step is compared with a predetermined standard value to evaluate whether or not the reception level of the noise signal is acceptable in the reception of the spread spectrum signal. A noise evaluation method comprising: a noise evaluation step. A noise extraction step for obtaining a frequency and a reception level of a noise signal included in a frequency band of a spread spectrum signal obtained by performing spread spectrum on a signal to be received;
The reception level corresponding to the detuning frequency from the center frequency of the signal to be received is calculated with respect to the noise signal, and the noise signal for each detuning frequency from the preset center frequency of the signal to be received is calculated. A noise evaluation method comprising: a noise evaluation step of evaluating whether or not the reception level of an acceptable noise signal in reception of the spread spectrum signal is compared with a standard value of a reception level corresponding to the number of peaks. The noise evaluation method according to claim 1 or 2, wherein the noise evaluation method is used for GPS (Global Positioning System). Noise extraction means for obtaining the frequency and reception level of a noise signal included in the frequency band of the spread spectrum signal obtained by spreading the signal to be received;
Noise suppression weighting means for adding a weight of a reception level according to a detuning frequency from a center frequency of the signal to be received to the noise signal;
A noise sum value calculating means for calculating a sum value of reception levels of noise signals weighted by the noise suppression weighting means;
The total noise signal reception level calculated by the noise total value calculation means is compared with a predetermined standard value to evaluate whether or not the reception level of the noise signal is acceptable in the reception of the spread spectrum signal. A noise evaluation device comprising noise evaluation means for Noise extraction means for obtaining the frequency and reception level of a noise signal included in the frequency band of the spread spectrum signal obtained by spreading the signal to be received;
Standard value storage means for storing a standard value of the reception level according to the number of peaks of the noise signal for each detuning frequency from the center frequency of the signal to be received;
The noise extraction means calculates the reception level corresponding to the detuning frequency from the center frequency of the signal to be received with respect to the noise signal for which the frequency and reception level have been obtained, and this and the standard value storage means store the reception level Compared with the standard value of the reception level according to the number of peaks of the noise signal for each detuning frequency from the center frequency of the signal to be received, whether the reception level of the noise signal is acceptable in the reception of the spread spectrum signal A noise evaluation apparatus comprising noise evaluation means for evaluating whether or not. 6. The noise evaluation apparatus according to claim 4, wherein the noise evaluation apparatus is used for GPS. The noise evaluation method according to claim 1 or 2, for a GPS receiver that is disposed at a predetermined distance from an electronic device that can be a noise generation source and receives a spread spectrum signal obtained by performing spread spectrum on a GPS band signal. A noise evaluation step for evaluating a reception level of a received noise signal in addition to the spread spectrum signal using
A distance changing step for changing a predetermined distance between the GPS receiver and the electronic device when the reception level of the noise signal evaluated in the noise evaluation step is not within an allowable range in receiving the spread spectrum signal;
The predetermined distance in which the reception level of the noise signal obtained as a result of the change in the distance changing step falls within an allowable range in the reception of the spread spectrum signal is optimized for the reception performance of the GPS receiver. A positioning method of a GPS receiving device, comprising: a relative distance determining step for determining a relative distance between an electronic device and the GPS receiving device. Using the noise evaluation method according to claim 1 or 2, for a GPS receiver mounted on a vehicle together with an electronic device that can be a noise generation source and receiving a spread spectrum signal obtained by spreading a signal of a GPS band, A noise evaluation step for evaluating a reception level of a noise signal received in addition to the spread spectrum signal;
A distance changing step for changing a relative distance between the GPS receiver and the electronic device when the reception level of the noise signal evaluated in the noise evaluation step is not within an allowable range in receiving the spread spectrum signal;
As a result of the change in the distance changing step, when a relative distance is obtained in which the reception level of the noise signal is within an allowable range in receiving the spread spectrum signal, the GPS reception is performed so as to satisfy the relative distance. An arrangement method of a GPS receiver, comprising: an arrangement step of arranging an apparatus and the electronic device in the vehicle. An electronic device characterized in that, using the noise evaluation method according to claim 1 or 2, the reception level of a noise signal given to a GPS receiver that receives a spread spectrum signal obtained by performing spread spectrum on a GPS band signal is evaluated. machine. A GPS receiver that receives a spread spectrum signal obtained by spectrum-spreading a GPS band signal is mounted together with an electronic device that can be a noise generation source, and the electronic device uses the noise evaluation method according to claim 1 or 2. A vehicle characterized in that a reception level of a noise signal applied to the GPS receiver is evaluated. A reception level of a noise signal given to a GPS receiver that receives a spread spectrum signal obtained by spreading a spectrum of a GPS band signal using the GPS receiver arrangement method according to claim 7 is acceptable in receiving the spread spectrum signal. An electronic apparatus characterized in that a relative distance as a range is obtained and arranged at a position satisfying the relative distance. A vehicle comprising: a GPS receiver that receives a spread spectrum signal obtained by spectrum-spreading a GPS band signal and an electronic device that can be a noise generation source using the GPS receiver arrangement method according to claim 8.

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