JP2829784B2 - FM-CW radar device - Google Patents
FM-CW radar deviceInfo
- Publication number
- JP2829784B2 JP2829784B2 JP30787090A JP30787090A JP2829784B2 JP 2829784 B2 JP2829784 B2 JP 2829784B2 JP 30787090 A JP30787090 A JP 30787090A JP 30787090 A JP30787090 A JP 30787090A JP 2829784 B2 JP2829784 B2 JP 2829784B2
- Authority
- JP
- Japan
- Prior art keywords
- frequency
- signal
- wave
- shift circuit
- local signal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Radar Systems Or Details Thereof (AREA)
Description
【発明の詳細な説明】 〔概 要〕 FM変調された搬送波を送信すると共に、該搬送波の一
部をローカル信号に使用して目標からの反射波とのビー
ト信号を得るFM−CWレーダ装置において、前記ローカル
信号の周波数を僅かにシフトする回路を設けることによ
り、FM−AM変換雑音の影響を軽減する。DETAILED DESCRIPTION OF THE INVENTION [Summary] An FM-CW radar apparatus that transmits a carrier wave modulated by FM and obtains a beat signal with a reflected wave from a target by using a part of the carrier wave as a local signal. By providing a circuit for slightly shifting the frequency of the local signal, the effect of FM-AM conversion noise is reduced.
本発明は、搬送波（CW）をFM変調して送信するFM−CW
レーダ装置に関する。The present invention relates to an FM-CW that modulates and transmits a carrier (CW) by FM.
The present invention relates to a radar device.
FM−CWレーダは第３図に示すように、電圧制御発振器
VCOの変調端子に三角波等のFM信号を入力して搬送波CW
にFM変調をかけ、これを送信波Ｔとして送信アンテナAN
T1から監視領域に送信する。この監視領域内の目標から
の反射波Ｒは受信アンテナANT2で受信され、ミキサMIX1
でビート信号Beatに変換される。このとき、ホモダイン
検波方式では送信波Ｔの一部をローカル信号LOとして使
用する。FM-CW radar is a voltage controlled oscillator as shown in Fig.3.
Input FM signal such as triangular wave to modulation terminal of VCO and carrier CW
FM modulation is applied to the transmission antenna T
Transmit from T1 to the monitoring area. The reflected wave R from the target in this monitoring area is received by the receiving antenna ANT2, and is mixed by the mixer MIX1.
Is converted into a beat signal Beat. At this time, in the homodyne detection method, a part of the transmission wave T is used as the local signal LO.
このFM−CWレーダはビート信号Beatから目標の速度情
報だけでなく距離情報も得られるので、車両の衝突防止
用等に使用される。Since the FM-CW radar can obtain not only target speed information but also distance information from the beat signal Beat, it is used for preventing vehicle collision and the like.
第３図のVCOをFM変調器とした場合、出力パワーの周
波数特性が非線形であるため、搬送波CWはFM変調と同時
にAM変調を受ける。このためローカル信号LOの振幅が変
動してその影響がビート信号Beatにも現れる。これがFM
−CWレーダ特有のFM−AM変換雑音である。この雑音は周
波数成分が低いため近距離の目標からの信号成分と重な
り、衝突の可能性が高い近距離の目標の検出を妨害す
る。When the VCO in FIG. 3 is an FM modulator, the carrier CW is subjected to AM modulation simultaneously with FM modulation because the frequency characteristic of output power is non-linear. For this reason, the amplitude of the local signal LO fluctuates, and its influence also appears in the beat signal Beat. This is FM
-FM-AM conversion noise peculiar to CW radar. Since this noise has a low frequency component, it overlaps with a signal component from a short-distance target, and interferes with detection of a short-distance target with a high possibility of collision.
本発明は信号の周波数域を高い方にシフトすることに
より、FM−AM変換雑音の影響を軽減しようとするもので
ある。The present invention seeks to reduce the influence of FM-AM conversion noise by shifting the frequency range of a signal to a higher one.
本発明は、FM変調された搬送波を送信すると共に、該
搬送波の一部をローカル信号に使用して目標からの反射
波とのビート信号を得るFM−CWレーダ装置において、前
記ローカル信号の周波数を該周波数よりも小さい第１の
所定の周波数だけ一方向へシフトさせる第１の周波数シ
フト回路と、該第１の周波数シフト回路でシフトさせた
周波数を該第１の所定の周波数と異なる第２の所定の周
波数だけ前記一方向とは逆方向に高周波側へシフトさせ
る第２の周波数シフト回路を設け、前記ローカル信号の
周波数と前記受信した反射波の周波数との間にFM−AM雑
音を除去する前記第２の周波数シフト回路でシフトさせ
た周波数の差をもたせることを特徴とするものである。The present invention provides an FM-CW radar device that transmits a carrier wave modulated by FM and obtains a beat signal with a reflected wave from a target by using a part of the carrier wave as a local signal. A first frequency shift circuit that shifts in one direction by a first predetermined frequency smaller than the frequency, and a second frequency shifter that shifts the frequency shifted by the first frequency shift circuit from the first predetermined frequency Providing a second frequency shift circuit that shifts by a predetermined frequency to the high frequency side in the direction opposite to the one direction, and removes FM-AM noise between the frequency of the local signal and the frequency of the received reflected wave. It is characterized in that a difference between the frequencies shifted by the second frequency shift circuit is provided.
ホモダイン検波の場合、ビート信号の周波数成分だけ
が得られる。これに対し、ローカル信号の周波数を僅か
にシフトすると一種のヘテロダイン検波になり、両搬送
波の周波数差（シフト分）がビート信号の周波数をシフ
トする。FM−AM雑音の周波数は低い領域に集中している
ため、周波数シフトでビート信号の周波数が高くなると
両者をフィルタで容易に分離することができ、FM−AM雑
音の影響、特に近距離の目標からの信号との混在を回避
できる。In the case of homodyne detection, only the frequency component of the beat signal is obtained. On the other hand, when the frequency of the local signal is slightly shifted, a kind of heterodyne detection is performed, and the frequency difference (shift amount) between the two carriers shifts the frequency of the beat signal. Since the frequency of the FM-AM noise is concentrated in the low region, if the frequency of the beat signal increases due to the frequency shift, the two can be easily separated by a filter. Can be avoided.
第１図は本発明の一実施例を示す構成図で、VCO、ANT
1、ANT2、MIX1は第３図の構成と変らない。本例はこの
構成に発振器PLO1,PLO2、ミキサMIX2,MIX3、バンドパス
フィルタBPF1,BPF2、２逓倍回路MUL1,MUL2からなるロー
カル信号の周波数シフト回路を追加したものである。FIG. 1 is a block diagram showing one embodiment of the present invention.
1, ANT2 and MIX1 are not different from the configuration of FIG. In this example, a local signal frequency shift circuit including oscillators PLO1 and PLO2, mixers MIX2 and MIX3, band-pass filters BPF1 and BPF2, and a doubler circuit MUL1 and MUL2 is added to this configuration.
送信波Ｔと反射波Ｒの搬送波周波数2F0が例えば60GHz
のように高い場合、周波数シフト処理はできるだけ低い
状態で行うことが望ましい。そこでVCOではその1/2の周
波数F0＝30GHzの搬送波を発振し、これに三角波でFM変
調をかける。その後２逓倍回路MUL1で2F0の送信波Ｔを
作るので、F0を分岐して作るローカル信号LOも最終的に
は２逓倍回路MLU2で２倍の周波数にする。The carrier frequency 2F 0 of the transmitted wave T and the reflected wave R is, for example, 60 GHz
In such a case, it is desirable that the frequency shift process be performed as low as possible. Therefore, the VCO oscillates a carrier wave having a frequency F 0 = 30 GHz, which is 1/2 of that frequency, and FM-modulates it with a triangular wave. Since then making transmission wave T of 2F 0 in doubling circuit MUL1, the local signal LO to make branches to F 0 also ultimately the frequency of 2 times 2 multiplier circuit MLU2.
その前にミキサMIX2ではF0を発振器PLO1の出力によっ
てf1だけシフトさせる。このf1はF0≫f1の関係にあり、
例えば1GHzである。この周波数シフトの結果ミキサMIX2
の出力にはF0−f1とF0＋f1とF0とf1が発生する。この中
からフィルタBPF1でF0−f1を抽出する。第２図（ａ）の
破線はこのBPF1の特性を示している。Before that is shifted by f 1 by the output of the oscillator PLO1 the F 0 In the mixer MIX2. This f 1 has a relationship of F 0 ≫f 1 ,
For example, 1 GHz. The result of this frequency shift is mixer MIX2
The output F 0 -f 1 and F 0 + f 1 and F 0 and f 1 is generated. From this, F 0 −f 1 is extracted by the filter BPF1. The dashed line in FIG. 2 (a) shows the characteristics of the BPF1.
次にミキサMIX3ではF0−f1を更に発振器PLO2の出力に
よってf1＋f2だけシフトさせる（f1≫f2）。f2は最終的
にシフトさせたい周波数の1/2の値であり、例えば25KHz
である。この結果ミキサMIX3の出力にはF0−2f1−f2とF
0＋f2とF0−f1とf1＋f2が発生する。この中からフィル
タBPF2でF0＋f2を抽出する。第２図（ｂ）の破線はこの
BPF2の特性である。Next, in the mixer MIX3, F 0 −f 1 is further shifted by f 1 + f 2 by the output of the oscillator PLO2 (f 1 ≫f 2 ). f 2 is a value of 1/2 of the frequency finally shifted, for example, 25 KHz
It is. As a result, the output of mixer MIX3 is F 0 −2f 1 −f 2 and F 0
0 + f 2 and F 0 -f 1 and f 1 + f 2 is generated. From this, F 0 + f 2 is extracted by the filter BPF2. The broken line in FIG.
This is the characteristic of BPF2.
最後に２逓倍回路MUL2でF0＋f2を２倍にすると、2F0
＋2f2のローカル信号LOが得られる。これは送信波Ｔの
周波数2F0を2f2（ここでは50KHz）だけシフトさせたも
のであり、当然反射波Ｒとの間にもこの周波数差があ
る。そこでＲとLOを入力とするミキサMIX1の出力を第２
図（ｃ）に示すような特性のフィルタBPF3に通すと、FM
−AM変換雑音を除去した信号成分を抽出できる。このフ
ィルタBPF3のカットオフ周波数は2f2＝50KHzとして20KH
z程度であり、これにより近距離の目標の信号をFM−AM
変換雑音と区別して抽出できる。Finally, if F 0 + f 2 is doubled by the doubling circuit MUL2, 2F 0
+ Local signal LO of 2f 2 is obtained. This is obtained by shifting the frequency 2F 0 of the transmission wave T by 2f 2 (here, 50 KHz), and there is naturally this frequency difference between the transmission wave T and the reflected wave R. Therefore, the output of mixer MIX1 with R and LO as inputs is
When passed through the filter BPF3 with the characteristics shown in Fig.
-A signal component from which AM conversion noise has been removed can be extracted. The cutoff frequency of this filter BPF3 is 20KH assuming 2f 2 = 50KHz
z so that the signal of the target at a short distance can be converted to FM-AM
It can be extracted separately from conversion noise.
上記実施例で中間的なシフト周波数f1を用いるのは、
最終シフト周波数f2で搬送波周波数F0を直接シフトして
F0＋f2だけを抽出するのが困難だからである。この周波
数シフトによるもう１つのメリットは、2f2をドップラ
周波数よりも或る程度高い値にすることで、三角波変調
時のアップ、ダウンの反転（信号抜け）を防止できる点
である。つまり、目標の距離と速度はビート信号のアッ
プ周波数とダウン周波数を用いて算出するが、目標が近
距離になるとアップとダウンの関係が反転する。これを
知らずに同じ算出式を使うと全く意味のない結果となる
が、アップ、ダウンの反転がなければこの問題は生じな
い。尚、周波数シフトはローカル信号を分岐した後の送
信波Ｔ或いは受信した反射波Ｒに対して行ってもよい
が、ロスの問題を考えればローカルについて行うのが最
良である。Use an intermediate shift frequency f 1 in the above embodiment,
Shift carrier frequency F 0 directly at final shift frequency f 2
This is because it is difficult to extract only F 0 + f 2 . Another advantage of this frequency shift is that by setting 2f 2 to a value that is somewhat higher than the Doppler frequency, it is possible to prevent up / down inversion (signal loss) during triangular wave modulation. In other words, the target distance and speed are calculated using the up frequency and the down frequency of the beat signal, but when the target is short, the relationship between up and down is reversed. If the same calculation formula is used without knowing this, a meaningless result will be obtained at all, but this problem does not occur unless up and down are inverted. The frequency shift may be performed on the transmitted wave T or the received reflected wave R after the local signal is branched, but it is best to perform the frequency shift on the local in consideration of the problem of loss.
以上述べたように本発明によれば、FM−CWレーダ特有
のFM−AM雑音の影響を軽減し、特に近距離目標の検知能
力を向上させることができる。また、本発明はローカル
信号と反射波との間に周波数シフトによる差をもたせた
ものであるため、ビート信号を抽出するためのバンドパ
スフィルタの帯域は従来と同じでよく、広げる必要はな
い。また周波数シフト回路をローカル信号側に設けてい
るので、送信波にロスが発生せず、精度が低下するとい
う問題はない。As described above, according to the present invention, it is possible to reduce the influence of FM-AM noise peculiar to FM-CW radar, and particularly to improve the ability to detect a short-range target. Further, since the present invention provides a difference due to a frequency shift between the local signal and the reflected wave, the band of the band-pass filter for extracting the beat signal may be the same as that of the related art, and does not need to be widened. In addition, since the frequency shift circuit is provided on the local signal side, there is no problem that loss does not occur in the transmission wave and accuracy is reduced.
第１図は本発明の一実施例を示す構成図、 第２図は各BPFの特性図、 第３図は従来のFM−CWレーダの概略図である。 図中、ANT1,ANT2はアンテナ、MIX1〜MIX3はミキサ、BPF
1〜BPF2はバンドパスフィルタ、VCOは電圧制御発振器、
PLO1,PLO2は発振器である。FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a characteristic diagram of each BPF, and FIG. 3 is a schematic diagram of a conventional FM-CW radar. In the figure, ANT1 and ANT2 are antennas, MIX1 to MIX3 are mixers, BPF
1 to BPF2 are bandpass filters, VCO is a voltage controlled oscillator,
PLO1 and PLO2 are oscillators.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭64−86085（ＪＰ，Ａ) 特開 平４−177190（ＪＰ，Ａ) 特開 平３−206987（ＪＰ，Ａ) 特開 平４−19588（ＪＰ，Ａ) 特開 平３−261883（ＪＰ，Ａ) 特開 平２−290582（ＪＰ，Ａ) 特開 平４−142486（ＪＰ，Ａ) 特開 平２−198379（ＪＰ，Ａ) (58)調査した分野(Int.Cl.6，ＤＢ名) G01S 13/34──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-64-86085 (JP, A) JP-A-4-177190 (JP, A) JP-A-3-206987 (JP, A) JP-A-4- 19588 (JP, A) JP-A-3-261883 (JP, A) JP-A-2-290582 (JP, A) JP-A-4-142486 (JP, A) JP-A-2-198379 (JP, A) (58) Field surveyed (Int. Cl. 6 , DB name) G01S 13/34
Claims (1)
搬送波の一部をローカル信号に使用して目標からの反射
波とのビート信号を得るFM−CWレーダ装置において、 前記ローカル信号の周波数を該周波数よりも小さい第１
の所定の周波数だけ一方向へシフトさせる第１の周波数
シフト回路と、 該第１の周波数シフト回路でシフトさせた周波数を該第
１の所定の周波数と異なる第２の所定の周波数だけ前記
一方向とは逆方向に高周波側へシフトさせる第２の周波
数シフト回路を設け、 前記ローカル信号の周波数と前記受信した反射波の周波
数との間にFM−AM雑音を除去する前記第２の周波数シフ
ト回路でシフトさせた周波数の差をもたせることを特徴
とするFM−CWレーダ装置。An FM-CW radar apparatus for transmitting a carrier wave modulated by FM and using a part of the carrier wave as a local signal to obtain a beat signal with a reflected wave from a target, Is smaller than the first frequency.
A first frequency shift circuit for shifting the frequency shifted by the predetermined frequency in one direction, and a frequency shifted by the first frequency shift circuit by a second predetermined frequency different from the first predetermined frequency. A second frequency shift circuit for shifting to the high frequency side in the opposite direction to the second frequency shift circuit for removing FM-AM noise between the frequency of the local signal and the frequency of the received reflected wave An FM-CW radar device characterized by having a difference in frequency shifted by (1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30787090A JP2829784B2 (en) | 1990-11-14 | 1990-11-14 | FM-CW radar device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30787090A JP2829784B2 (en) | 1990-11-14 | 1990-11-14 | FM-CW radar device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04178589A JPH04178589A (en) | 1992-06-25 |
| JP2829784B2 true JP2829784B2 (en) | 1998-12-02 |
Family
ID=17974152
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30787090A Expired - Fee Related JP2829784B2 (en) | 1990-11-14 | 1990-11-14 | FM-CW radar device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2829784B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100668363B1 (en) * | 2005-12-08 | 2007-01-16 | 한국전자통신연구원 | Millimeterwave rf transceiver for radar senor |
| US7652617B2 (en) * | 2006-06-01 | 2010-01-26 | University Of Florida Research Foundation, Inc. | Radar microsensor for detection, tracking, and classification |
| JP2009109380A (en) * | 2007-10-31 | 2009-05-21 | Toyota Central R&D Labs Inc | Radar device |
| JP5750214B2 (en) * | 2009-03-30 | 2015-07-15 | 日本信号株式会社 | Wireless distance / speed measuring device |
-
1990
- 1990-11-14 JP JP30787090A patent/JP2829784B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04178589A (en) | 1992-06-25 |
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