JP3767837B2 - Method and apparatus for detecting buried life form - Google Patents

Description

【００２６】
説明を簡明にするため、減算器３２は無いと仮定すると、検波器３６に入力される受信信号ｅ_rは、次式で表わすことができる。

他方、分配／合成器２２により分岐された送信信号の一部ｅ_cは、次式で表わすことができる。
ｅ_c＝ａ_c cosωt （４）
【００２７】
乗算器Ｍ₁によりｅ_cとｅ_rを乗算すると、

また、乗算器Ｍ₂により、ｅ_cを９０度移相した信号ｅ_s、すなわちａ_c sinωtとｅ_rを乗算すると、
ｅ_s×ｅ_r＝(1／2)ａ_m{sinω(2t−τ)＋sinωτ} （６）
【００２８】
（５）式及び（６）式において、右辺を展開したときの第１項は、放射電波の２倍の周波数を持つが、同第２項におけるωτは、反射体が静止物体の場合は一定であり、運動体の場合でも、その変化の周波数は第１項に比して極めて低い。したがって、これら乗算器の出力から低域フィルタにより高周波成分を除くと、（５）式及び（６）式の右辺第１項に対応する成分が除去されて、次式で表わされる出力Ｅ₁’及びＥ₂’が得られる。
Ｅ₁’＝(1／2)ａ_m cosωτ （７）
Ｅ₂’＝(1／2)ａ_m sinωτ （８）
【００２９】
以上の説明は、任意の一つの反射波についてのものであり、したがって、探知対象である運動体、例えば生体からの反射波の位相（電波が往復に要する時間）をτ_oとし、それ以外の障害物、すなわち静止物からの反射波の位相をτ_nで代表すれば、前掲出力Ｅ₁’及びＥ₂’は次のようになるはずである。
Ｅ₁’＝(1／2)ａ_m cosωτ_o＋(1／2)ａ_m' cosωτ_n （９）
Ｅ₂’＝(1／2)ａ_m sinωτ_o＋(1／2)ａ_m' sinωτ_n （１０）
【００３０】
上掲２式の右辺第２項は、探知対象とは無関係な、いわばノイズである。ところが、通常、ａ_m'はａ_mよりも著しく大きいため、このままでは、第１項、すなわち探知対象に対応する所望の信号がこのノイズの中に埋もれてしまい、十分な感度が得られない。
【００３１】
そこで、減算器３２及び不要反射波相殺信号発生器６２が設けられる。分配／合成器２６の分岐出力ｅ_pの位相と振幅を、可変移相器と可変減衰器により、増幅器３１からの受信信号の主要成分のそれらととほぼ等しくなるように調整し、それを減算器３２に供給して、増幅器３１からの受信信号から差し引く。実際には、減算器３２の出力をレベルメータなどで監視しながら、それが最小となるように、前記可変移相器と可変減衰器を調節すればよい。これにより、（９）式と（１０）式の右辺第２項の振幅を、同第１項に対する後述の検知処理に支障がない程度に、小さくすることができる。
【００３２】
ところで、探知対象である運動体とアンテナの間の距離は、探知対象の表面の動き、例えば、生体の呼吸、心拍、身体各部の動きなどに応じて、僅かであるが変動し、それに起因して、対象物からの反射波の位相τ_oが変動する。したがって、（９）式及び／又は（１０）式の変化分を調べれば、探知対象である運動体を検知することができる。
【００３３】
さて、探知対象までの距離の平均値をＲ_oで表わし、変動分をｒで表わせば、
ωτ_o＝ω・2(R_o＋r)／V＝(2ω／V)R_o＋(2ω／V)r
ここで、２ω／ＶとＲ_oは一定であるから、（２ω／Ｖ）Ｒ_o＝Ａ、２ω／Ｖ＝Ｂと置けば、（９）式と（１０）式は次のように書き替えられる。ただし、前述のようにして低減された不要反射波信号の残渣をΔＥ₁とΔＥ₂で表わす。
Ｅ₁’＝(1／2)ａ_m cos(A＋Br)＋ΔＥ₁
Ｅ₂’＝(1／2)ａ_m sin(A＋Br)＋ΔＥ₂
【００３４】
しかるに、Ｒ_oは数ｍ程度であるのに対して、ｒはせいぜい数ｃｍ程度であるから、|Ａ|≫|Ｂｒ|であり、したがって、次の近似式が成り立つ。
Ｅ₁’≒(1／2)ａ_m{cosA−Br sinA}＋ΔＥ₁ （１１）
Ｅ₂’≒(1／2)ａ_m{sinA＋Br cosA}＋ΔＥ₂ （１２）
【００３５】
これら２式の右辺を展開したときの第１項と第３項は一定、すなわち直流成分であから、高域フィルタによって除去することができ、それにより、第２項が示す反射波信号の変化分、すなわち探知対象である運動体を、検知することができる。
【００３６】
図４における帯域フィルタ３６３及び３６４は、前記高域フィルタと、先に述べた、（５）及び（６）式から（７）及び（８）式を得るための低域フィルタとを、合成したものと等価なフィルタである。したがって、増幅器３６５及び３６６の出力として、探知対象である運動体の動きを示す次式の信号Ｅ１及びＥ２が得られる。
Ｅ₁≒−(1／2)ａ_mBr sinA （１３）
Ｅ₂≒(1／2)ａ_mBr cosA （１４）
【００３７】
なお、９０度位相が異なる検波出力Ｅ₁及びＥ₂を発生させる理由は、次のとおりである。すなわち、変化量ｒの係数であるsinＡとcosＡにおいて、Ａすなわち（２ω／Ｖ）Ｒ_oがπの整数倍に近い時には、sinＡ≒０となるので、Ｅ₁による検知は不可能になるが、｜cosＡ｜≒１となるので、Ｅ₂による検知の感度は最大となり、また、Ａがπ／２の整数倍に近いときには、cosＡ≒０となるので、Ｅ₂による検知は不可能となるが、｜sinＡ｜≒１となるので、Ｅ₁による検知の感度は最大となる。したがって、探知対象までの距離の如何にかかわらず、検出不能という事態を避けることができるのである。
【００３８】
本実施形態では、検波出力Ｅ₁及びＥ₂を、そのままペンレコーダ１１で記録するが、それに代えて、ＣＲＴ、液晶等による動的な表示装置に表示してもよい。しかし、この型の表示装置では、複数の送信アンテナから逐次的に送信したときに逐次的に得られる検波出力の全体を、同時に比較観察することができない。これが簡単にできる点で、ペンレコーダが有利である。動的な表示装置でこれを可能にするには、記憶・編集機能が必要であるが、それは、マイクロコンピュータを使えば容易に実現することができる。
【００３９】
他の出力形式として、検波出力Ｅ₁及びＥ₂によりそれぞれ電圧制御型の可変周波発振器を制御し、これらの発振器の出力をヘッドホン等で聴取して、その周波数変化により、対象物の動きを検知することも可能である。その場合、検波出力Ｅ₁及びＥ₂は、ｒ、すなわち探知対象の距離の変動分に比例しているが、その周波数は通常非常に低い。例えば、心拍は１ヘルツ前後であり、呼吸は０．４ヘルツ前後である。そこで、検波出力Ｅ₁及びＥ₂に適当なバイアス電圧を加えて、可変周波発振器の発振周波数が、聴取し易い周波数、例えば８００ヘルツ付近を中心として、変動するように調整するのがよい。しかし、この方法も、検波出力の全体を同時に比較聴取することはできないのが、難点である。
【００４０】
あるいはまた、高速フーリエ変換器により、検波出力Ｅ₁及びＥ₂の周波数解析を行なって、そのスペクトル分布を表示してもよい。
【００４１】
前述の実施形態では、送信アンテナ具と受信アンテナ具の双方を複数個用いたが、どちらか一方を１個にしても、単一の送受信アンテナ具又は１対の送信アンテナ具と受信アンテナ具のみを用いる場合と比較すれば、埋没生存者の探知の確率は大幅に向上する。
【００４２】
また、複数の受信アンテナ具にそれぞれ別個の受信回路を固定的に接続する代りに、１個の受信器を複数の受信アンテナ具に順次切替えて接続してもよい。こうすると、検波出力の全体を同時に比較観察するのには甚だ不便であるが、コストは大幅に下げることができる。
【００４３】
図５ないし図１０は、呼吸に伴う体表面の変位の検知において、埋没生存者自身及びその近辺の状況により変化する検波出力波形の実験例を示す。これらの図において、送信アンテナ具Ｔｘと受信アンテナ具Ｒｘは一つの水平面上にあり、両アンテナ具は、この水平面内で９０度の角度をなしている。
【００４４】
図５は、送信アンテナ具を身体の正面に挿入し、受信アンテナ具を側方に挿入した場合であって、十分な振幅の周期的波形から、呼吸に伴う体表面の変位、すなわち埋没生存者の存在を、明確に検知することができる。
【００４５】
図６は、送信アンテナ具を身体の正面から４５度外れた所に挿入し、受信アンテナ具を側方から４５度後方に挿入した場合であって、この場合でも、呼吸に伴う体表面の変位をかなり明確に検知することができる。
【００４６】
図７は、送信アンテナ具を身体の側方に挿入し、受信アンテナ具を後方に挿入した場合であり、図８は、送信アンテナ具を身体の後方に挿入し、、受信アンテナ具を側方に挿入した場合であって、いずれの場合も、出力の振幅が小さく、各種のノイズが多い実際の場面では、呼吸に伴う体表面の変位、すなわち埋没生存者の存在を、明確に検知することは容易ではない。
【００４７】
図９は、図５と同じ送信アンテナ具と受信アンテナ具の配置において、埋没生存者の正面に、身体が隠れる程度の大きさの金属板が存在する場合であって、やはり出力の振幅は小さく、実地において呼吸に伴う体表面の変位を明確に検知することは困難である。
【００４８】
図１０は、図５と同じ送信アンテナ具と受信アンテナ具の配置角度において、堆積物中に挿入した受信アンテナ具（Ｒｘ１）と、堆積物の外に出した受信アンテナ具（Ｒｘ２）の検波出力を、対比的に示す。波形図の中央付近に現れた大振幅部分は、近くを通った自動車に起因するものであるが、挿入された受信アンテナ具からの出力だけを見たのでは、手足の突発的な動きなのかどうか、判別できない。また、このようなノイズが大小多数現れると、図７ないし９のような場合には特に、呼吸に伴う体表面の変位の検知が困難になる。しかし、このように対比観察すれば、堆積物の外部における運動物体からのノイズが特定できるから、それらがないものとみなすことにより、手足の突発的動きや呼吸に伴う体表面の変位の検知が容易になる。
【００４９】
したがって、図１に示した配置において、更に１個の受信アンテナ具とそれに接続された受信器とを追加し、この受信アンテナ具は堆積物の中に挿入せずに、その外に出しておき、その出力も含めて諸検波出力を総合判断するのも、甚だ有用である。
【００５０】
【発明の効果】
本発明によれば、堆積物中の埋没生存者を、その埋没状況に左右されることなく、また、周囲の運動物体、例えば作業中の人間や移動中の車両などの影響を受けずに、迅速確実に探知することができる。
【図面の簡単な説明】
【図１】本発明による埋没生存者探知方法の一形態を示す概念図。
【図２】本発明で用いられるアンテナ具の一例を示す図。
【図３】本発明で用いられる送受信器の回路構成の一例を示すブロック図。
【図４】受信器内の検波器の回路構成の一例を示すブロック図。
【図５】埋没状況により変化する検波出力の第１の例を示す図。
【図６】埋没状況により変化する検波出力の第２の例を示す図。
【図７】埋没状況により変化する検波出力の第３の例を示す図。
【図８】埋没状況により変化する検波出力の第４の例を示す図。
【図９】埋没状況により変化する検波出力の第５の例を示す図。
【図１０】堆積物中に挿入された受信アンテナ具と外に置かれた受信アンテナ具の検波出力を示す図。
【符号の説明】
１…堆積物 ２…埋没者 ３…スチール家具 ４〜６…送信アンテナ具 ７〜９…受信アンテナ具 １０…送受信器 １１…ペンレコーダ ２０…送信器 ２８…切替スイッチ ３０、４０、５０…受信器 ３２…減算器 ３６…検波器 ６２…不要反射波相殺信号発生器 ６５…９０度移相器[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for searching for a life form confined in a collapsed building, accumulated rubble, earth and sand, snow (hereinafter referred to as sediment). Such a technique is particularly useful for finding buried survivors during disasters.
[0002]
[Prior art]
Insert a saddle-shaped antenna device with a structure in which both a small transmitting antenna and a receiving antenna are provided at the tip of the saddle-shaped support member into the deposit, and reflect the reflected wave of the microwave radiated from the transmitting antenna. Receiving with a receiving antenna and examining the characteristics of this reflected wave, such as phase change, to reduce the influence of the reflected wave (noise) from the surface of the deposit and surrounding moving objects, and the body surface accompanying breathing and heartbeat A method has been already proposed (Japanese Patent Application No. 8-125475) for detecting the movement of each part of the body such as a small displacement or limb with high sensitivity, and thereby detecting the buried life form.
[0003]
As a modification of this method, it is also possible to prepare a similar bowl-shaped transmitting antenna device and receiving antenna device separately, insert them into the deposit, and detect a living object according to the same principle as described above. .
[0004]
[Problems to be solved by the invention]
Detecting the displacement of the body surface due to breathing may be the most promising for detecting buried survivors during a disaster. If you are alive, you are always breathing, and the displacement of the body surface that accompanies the breathing is quite noticeable, and it is steady and periodic, so compare its detection output with noise This should be easy.
[0005]
However, subsequent research has created several problems. First of all, the burial situation at the time of a disaster is very different, and therefore, there is a great difference in the detection sensitivity of the displacement of the body surface accompanying breathing. As for the situation of the buried subject itself, there are differences such as whether they are facing, standing or sleeping. The amount of deformation of the chest due to respiration differs considerably, for example, in the front-rear direction and the left-right direction, and as a result, a significant difference in detection sensitivity is considered to occur due to the relative relationship between the body direction and the radio wave transmission / reception direction.
[0006]
In addition, if there is a large radio wave reflector, such as steel furniture, on one side of the buried person, the radiation wave from that direction and / or the reflected wave wave in that direction will be greatly attenuated. As a result, the detection sensitivity in this direction is significantly reduced.
[0007]
If the detection operation is continued by changing the insertion positions of a single transmission / reception antenna tool or a pair of transmission antenna tools and reception antenna tools one after another, it will eventually be possible to find a position where sufficiently high sensitivity can be obtained. Let's go. However, since detection of buried survivors at the time of a disaster competes for a moment, the time required for detection work must be shortened as much as possible.
[0008]
Furthermore, even if the antenna device having the structure as described above is inserted into debris or the like, the radio waves leaking out of the deposit and the radio waves entering from the outside are not negligible. If there is a large moving object such as a working person or a moving vehicle, it is also detected, which may make it difficult to detect the movement of an important buried survivor.
[0009]
[Means for Solving the Problems]
The method of the present invention uses a plurality of saddle-shaped transmission antennas and reception antennas as described above, at least one of which is inserted at different positions on the deposit, and comprehensively evaluates the detection output of the received waves. To do.
[0010]
When there are a plurality of transmission antenna tools, radio waves are sequentially transmitted from these transmission antenna tools, and the detection output obtained in each case is comprehensively evaluated. When there are a plurality of receiving antennas, these received waves are detected sequentially or in parallel and output, and these outputs are comprehensively evaluated. For example, by comparing various detection outputs, if there are several output waveforms with different amplitudes in the same period, it may be determined that it is almost certain that there are buried survivors.
[0011]
An example of the embedded arrangement of the transmitting antenna tool and the receiving antenna tool is that each antenna of the transmitting antenna tool and the receiving antenna tool has a gentle directivity in the length direction of their supporting members, and all the antenna tools are used. It is to insert radially toward almost one point in the sediment.
[0012]
In the case of using a plurality of receiving antenna tools, one of them may be left outside without being inserted into the deposit. Since the detection output from the antenna of this receiving antenna tool mainly represents the movement of an external moving object, the detection of the buried survivor is detected in the detection output from the antenna of the receiving antenna tool inserted in the sediment by comparing it with it. It becomes easy to identify the output or the detection output of an external moving object.
[0013]
The apparatus of the present invention used to implement the method includes a plurality of saddle-shaped transmission antennas as described above, a single transmitter that generates a high-frequency signal, and any one of the plurality of transmission antennas. A selector switch for selectively supplying the output of the transmitter, a plurality of bowl-shaped receiving antennas, and a signal connected to each of the plurality of receiving antennas to detect signals from the receiving antennas. A plurality of receivers, and an output device connected to the plurality of receivers.
[0014]
As a detection circuit, a first detection circuit that detects a phase of a received signal using a reference signal of a transmission signal and a second detection circuit that detects a phase of the reception signal using a signal that is 90 degrees out of phase with the reference signal of the transmission signal are provided. This increases the certainty of detection of buried survivors.
[0015]
In addition, an adjustment circuit that receives the branch signal of the transmission signal and adjusts the phase and amplitude thereof is provided, and in each of the reception circuits, the output of the adjustment circuit is subtracted from the reception signal and reflected from a stationary object in the reception signal. It is advantageous to provide a circuit for suppressing a signal corresponding to a wave in a stage preceding the detection circuit.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 conceptually shows an example of a state in which a plurality of saddle-like transmitting antenna devices and receiving antenna devices are inserted into a deposit to detect a surviving survivor according to the present invention. A buried survivor 2 is confined in a deposit 1 such as a wreckage of a collapsed house, and a steel furniture 3 has fallen beside it. The plurality of bowl-shaped transmitting antenna tools 4 to 6 (TxA to TxC) and the receiving antenna tools 7 to 9 (RxA to RxC) are inserted as deep as possible into the spaced locations of the deposit 1. If there is an appropriate gap, it will be used as much as possible, but in some cases it will also be necessary to drill holes in the deposit using a rock drill or the like.
[0017]
A small antenna is attached to the tip of each antenna tool. In the embodiment described here, each antenna has a moderate directivity in the length direction of the antenna tool. In that case, the various antenna tools are arranged radially so that they are almost directed to a suitable point inside the deposit, and so that the transmitting antenna tools and the receiving antenna tools are distributed at substantially equal angular intervals. It is good to do. For example, as shown in the example, when three transmitting antenna devices and three receiving antenna devices are used, the transmitting antenna device and the receiving antenna device are alternately arranged at an angular interval of about 60 degrees. Insert it towards the center of (or if you can estimate the likely location of the buried subject). In this way, a plurality of transmitting antenna devices and receiving antenna devices are distributed evenly over the entire circumference of the deposit, so that the direction of the body of the buried survivor and the presence of radio wave obstacles such as the steel furniture 3 can be reduced. Regardless, the probability of detecting buried survivors can be greatly increased.
[0018]
Each of the transmission antenna devices 4 to 6 and each of the reception antenna devices 7 to 9 are connected to the transmission terminal and the reception terminal of the transceiver 10 by an appropriate cable such as a coaxial cable. In this embodiment, the detection signal obtained by detecting the signal from each receiving antenna is output to the pen recorder 11.
[0019]
FIG. 2 shows an example of a bowl-shaped antenna device used in the present invention. (A) is a general view, (b) is a cross-sectional view of the tip. The transmitting antenna device and the receiving antenna device have the same structure. A microstrip antenna 13 covered with a circular lid is attached to the tip of a stainless steel tube 12 having a length of about 1.5 meters, and a cable 14 connecting the antenna and a transmitter or receiver is connected to the tube 12. It passes through. The thickness of this antenna tool is about 7 centimeters at the thickest place. This antenna has a gentle directivity in the length direction of the antenna device.
[0020]
Next, the transceiver will be described. FIG. 3 is a block diagram showing an example of a circuit structure of a superheterodyne transmitter and receiver. In the transmitter 20, the output of the high-frequency generator 21 passes through a distributor / synthesizer 22, an amplifier 23, a mixer 24, an amplifier 25, a distributor / synthesizer 26 and an amplifier 27 in this order, and a manual or timer-controlled changeover switch 28. Thus, the antennas are sequentially supplied to the antennas of the plurality of transmitting antenna devices 4 to 6 for a predetermined period (for example, one minute).
[0021]
On the other hand, the antennas of the plurality of receiving antenna devices 7 to 9 are connected to the receivers 30, 40 and 50, respectively, and therefore the outputs of the plurality of receiving antennas are output simultaneously. Since the structures of these receivers are the same, the receiver 30 will be described below. In the receiver 30, the signal from the antenna of the receiving antenna tool 7 is supplied to the detector 36 through the amplifier 31, the subtractor 32, the amplifier 33, the mixer 34 and the amplifier 35 in this order, and the phase is different by 90 degrees. It is converted into a pair of detection outputs E ₁ and E ₂ . The detection outputs E ₁ and E ₂ are recorded by the multipoint pen recorder 11.
[0022]
The output of the local oscillator 60 is also supplied to the mixer 24 in the transmitter and the mixer 34 in the receiver. A distributor / synthesizer 61 is inserted to distribute the output of the local transmitter 60 to a plurality of receivers. Branch output e _p of the distributor / combiner 26 in the transmitter is fed to the unnecessary reflected wave cancellation signal generator 62, the output e _q of the generator 62, through the distributor / synthesizer 63, the receiver Is supplied to the subtractor 32. Outcoupling e _c of the distributor / combiner 22 in the transmitter is further 2 minutes by the distributor / synthesizer 64, one directly, the other is through the 90-degree phase shifter 65, is supplied to the detector 36.
[0023]
Unnecessary reflected wave cancellation signal generator 62 is made variable phase shifter and a variable attenuator, these distribution / branch output e _p of the combiner 26 is adjusted phase and amplitude, respectively, unnecessary reflected wave cancellation signal e _q .
[0024]
FIG. 4 shows the internal configuration of the detector 36. The signal e _r from the amplifier 35 is 2 minutes, one of which is supplied as a multiplicand signal to the multiplier M ₁ 361, the other is supplied as multiplicand signal to the multiplier M ₂ 362. Furthermore, the direct output of the distributor / synthesizer 64, i.e. branch output e _c of the distributor / combiner 22 in the transmitter is supplied as a multiplier signal directly to the multiplier M _1, also further from the distributor / synthesizer 64 90 signal e _s passing through the degrees phase shifter 65 is supplied as a multiplier signal to the multiplier M _2. The outputs of the multipliers M ₁ and M ₂ pass through band-pass filters 363 and 364, respectively, and are amplified by amplifiers 365 and 366 to become detection outputs E ₁ and E ₂ .
[0025]
Here, the operation of the circuit shown in FIGS. 3 and 4, particularly the receiver, will be described. In general, the transmission signal e _T and the reception signal e _R can be expressed by the following equations.

[0026]
For simplicity of explanation, the subtracter 32 is assuming no received signal e _r input to the detector 36 can be expressed by the following equation.

On the other hand, some e _c of the branch transmission signal by the distributor / combiner 22 can be expressed by the following equation.
e _c = a _c cosωt (4)
[0027]
Multiplying e _c and e _r by the multiplier M _1,

Further, by the multiplier M _2, the signal e _s by 90 degrees phase shifted e _c, that is, multiplying a _c sin .omega.t and e _{r,
e s × e r = (1/2} ) a m {sinω (2t-τ) + sinωτ} (6)
[0028]
In equations (5) and (6), the first term when the right side is expanded has a frequency twice that of the radiated radio wave, but ωτ in the second term is constant when the reflector is a stationary object. Even in the case of a moving body, the frequency of the change is very low compared to the first term. Therefore, when a high frequency component is removed from the outputs of these multipliers by a low-pass filter, the component corresponding to the first term on the right side of the equations (5) and (6) is removed, and an output E ₁ ′ expressed by the following equation: And E ₂ '.
_{E 1 '= (1/2) a} m cosωτ (7)
_{E 2 '= (1/2) a} m sinωτ (8)
[0029]
The above description is about an arbitrary reflected wave. Therefore, the phase of the reflected wave from the moving object to be detected, for example, the living body (the time required for the radio wave to reciprocate) is τ _o , If the phase of the reflected wave from an obstacle, that is, a stationary object is represented by τ _n , the outputs E ₁ ′ and E ₂ ′ should be as follows.
_{E 1 '= (1/2) a} m cosωτ o + (1/2) a m' cosωτ n (9)
_{E 2 '= (1/2) a} m sinωτ o + (1/2) a m' sinωτ n (10)
[0030]
The second term on the right side of the above-mentioned formula 2 is so-called noise that has nothing to do with the detection target. However, since a _m ′ is usually much larger than a _m , the first term, that is, the desired signal corresponding to the detection target is buried in this noise, and sufficient sensitivity cannot be obtained.
[0031]
Therefore, a subtractor 32 and an unnecessary reflected wave cancellation signal generator 62 are provided. The phase and amplitude of the branched output e _p of the distributor / combiner 26, the variable phase shifter and a variable attenuator, adjusted to be approximately equal and their major component of the received signal from the amplifier 31, subtracts it The signal is supplied to the amplifier 32 and subtracted from the received signal from the amplifier 31. In practice, while monitoring the output of the subtractor 32 with a level meter or the like, the variable phase shifter and the variable attenuator may be adjusted so as to minimize the output. As a result, the amplitude of the second term on the right side of Equations (9) and (10) can be reduced to the extent that there is no hindrance to the detection processing described later for the first term.
[0032]
By the way, the distance between the object to be detected and the antenna fluctuates slightly depending on the movement of the surface of the object to be detected, for example, respiration of the living body, heartbeat, movement of each part of the body, and the like. Thus, the phase τ _o of the reflected wave from the object varies. Therefore, if the amount of change in Equation (9) and / or Equation (10) is examined, the moving object that is the detection target can be detected.
[0033]
Now, if the average value of the distance to the detection target is represented by R _o and the variation is represented by r,
ωτ _o = ω · 2 (R _o + r) / V = (2ω / V) R _o + (2ω / V) r
Here, since 2ω / V and R _o are constant, if (2ω / V) R _o = A and 2ω / V = B are set, equations (9) and (10) can be rewritten as follows: It is done. However, the residue of the unnecessary reflected wave signal reduced as described above is represented by ΔE ₁ and ΔE ₂ .
_{E 1 '= (1/2) a} m cos (A + Br) + ΔE 1
_{E 2 '= (1/2) a} m sin (A + Br) + ΔE 2
[0034]
However, since R _o is about several meters, r is about several centimeters at most, so | A | >> | Br |. Therefore, the following approximate expression holds.
_{E 1 '≒ (1/2) a} m {cosA-Br sinA} + ΔE 1 (11)
_{E 2 '≒ (1/2) a} m {sinA + Br cosA} + ΔE 2 (12)
[0035]
The first and third terms when the right sides of these two expressions are expanded are constant, that is, they are direct current components, and therefore can be removed by a high-pass filter, thereby changing the reflected wave signal indicated by the second term. Minute, that is, a moving body that is a detection target can be detected.
[0036]
The band-pass filters 363 and 364 in FIG. 4 are a combination of the high-pass filter and the low-pass filter for obtaining the equations (7) and (8) from the equations (5) and (6) described above. It is a filter equivalent to the one. Therefore, as the outputs of the amplifiers 365 and 366, the following signals E1 and E2 indicating the motion of the moving body that is the detection target are obtained.
_{E 1 ≒ - (1/2) a} m Br sinA (13)
_{E 2 ≒ (1/2) a m} Br cosA (14)
[0037]
The reason for generating the detection outputs E ₁ and E ₂ that are 90 degrees out of phase is as follows. That is, in sinA and cosA which are coefficients of the change amount r, when A, that is, (2ω / V) R _o is close to an integral multiple of π, sinA≈0, so detection by E ₁ becomes impossible. Since | cosA | ≈1, the sensitivity of detection by E ₂ is maximized, and when A is close to an integer multiple of π / 2, cosA≈0, so detection by E ₂ is impossible. , | SinA | ≈1, so that the sensitivity of detection by E ₁ is maximized. Therefore, it is possible to avoid a situation where detection is impossible regardless of the distance to the detection target.
[0038]
In the present embodiment, the detection outputs E ₁ and E ₂ are recorded by the pen recorder 11 as they are, but may instead be displayed on a dynamic display device such as a CRT or a liquid crystal. However, in this type of display device, the entire detection output obtained sequentially when transmitting sequentially from a plurality of transmitting antennas cannot be compared and observed simultaneously. A pen recorder is advantageous in that this can be done easily. In order to make this possible with a dynamic display device, a memory / editing function is required, which can be easily realized by using a microcomputer.
[0039]
Other output formats, respectively controls the variable frequency oscillator of the voltage controlled by the detection output E ₁ and E _2, and listening to the output of these oscillators with headphones or the like, by its frequency change, detecting the movement of the object It is also possible to do. In this case, the detection outputs E ₁ and E ₂ are proportional to r, that is, the variation in the distance to be detected, but the frequency is usually very low. For example, the heart rate is around 1 hertz and the respiration is around 0.4 hertz. Therefore, it is preferable that an appropriate bias voltage is applied to the detection outputs E ₁ and E _{2 so} that the oscillation frequency of the variable frequency oscillator is adjusted so as to fluctuate around an easily audible frequency, for example, around 800 Hz. However, this method also has a difficulty in that the entire detection output cannot be compared and listened simultaneously.
[0040]
Alternatively, a frequency analysis of the detection outputs E ₁ and E ₂ may be performed by a fast Fourier transformer to display the spectrum distribution.
[0041]
In the above-described embodiment, a plurality of transmission antennas and reception antennas are used. However, even if either one is used, only a single transmission / reception antenna tool or a pair of transmission antennas and reception antennas is used. Compared with the use of, the probability of detection of buried survivors is greatly improved.
[0042]
Further, instead of fixedly connecting separate receiving circuits to the plurality of receiving antennas, one receiver may be switched to the plurality of receiving antennas in order. This is very inconvenient for comparing and observing the entire detection output at the same time, but the cost can be greatly reduced.
[0043]
FIGS. 5 to 10 show examples of detection output waveforms that change depending on the situation of the surviving survivor and the vicinity thereof in detecting the displacement of the body surface accompanying breathing. In these drawings, the transmitting antenna device Tx and the receiving antenna device Rx are on one horizontal plane, and both antenna tools form an angle of 90 degrees in this horizontal plane.
[0044]
FIG. 5 shows a case where the transmitting antenna device is inserted in front of the body and the receiving antenna device is inserted sideways, and from the periodic waveform with sufficient amplitude, the displacement of the body surface accompanying respiration, ie, the buried survivor Can be clearly detected.
[0045]
FIG. 6 shows a case where the transmitting antenna device is inserted at a position 45 degrees away from the front of the body, and the receiving antenna device is inserted 45 degrees rearward from the side. Can be detected fairly clearly.
[0046]
FIG. 7 shows a case where the transmitting antenna tool is inserted into the side of the body and the receiving antenna tool is inserted backward, and FIG. 8 shows that the transmitting antenna tool is inserted into the back of the body and the receiving antenna tool is laterally inserted. In any case, the displacement of the body surface that accompanies breathing, that is, the presence of a surviving survivor, should be clearly detected in an actual scene where the output amplitude is small and there are various noises. Is not easy.
[0047]
FIG. 9 shows a case where there is a metal plate that is large enough to hide the body in front of the buried survivor in the same arrangement of the transmitting antenna device and the receiving antenna device as in FIG. In actual practice, it is difficult to clearly detect the displacement of the body surface accompanying breathing.
[0048]
FIG. 10 shows the detection output of the receiving antenna tool (Rx1) inserted into the deposit and the receiving antenna tool (Rx2) put out of the deposit at the same arrangement angle of the transmitting antenna tool and the receiving antenna tool as in FIG. Is shown in contrast. The large-amplitude part that appears near the center of the waveform diagram is due to a car passing nearby, but is it just a sudden movement of the limb when only the output from the inserted receiving antenna tool is seen? I can't tell. Further, when such a large or small amount of noise appears, it becomes difficult to detect the displacement of the body surface due to respiration, particularly in the case of FIGS. However, since this observation can identify noise from moving objects outside the deposit, it can detect sudden movement of the limbs and displacement of the body surface due to breathing by assuming that there is no noise. It becomes easy.
[0049]
Therefore, in the arrangement shown in FIG. 1, an additional receiving antenna device and a receiver connected to the receiving antenna device are added, and this receiving antenna device is not inserted into the deposit, but left outside. It is also very useful to comprehensively judge the detection output including its output.
[0050]
【The invention's effect】
According to the present invention, the survivor buried in the deposit is not affected by the buried state, and without being influenced by surrounding moving objects such as a working person or a moving vehicle, It can be detected quickly and reliably.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing an embodiment of a buried survivor detection method according to the present invention.
FIG. 2 is a diagram showing an example of an antenna tool used in the present invention.
FIG. 3 is a block diagram showing an example of a circuit configuration of a transceiver used in the present invention.
FIG. 4 is a block diagram showing an example of a circuit configuration of a detector in the receiver.
FIG. 5 is a diagram showing a first example of a detection output that changes depending on a buried state.
FIG. 6 is a diagram showing a second example of the detection output that changes depending on the buried state.
FIG. 7 is a diagram showing a third example of the detection output that changes depending on the buried state.
FIG. 8 is a diagram showing a fourth example of the detection output that changes depending on the buried state.
FIG. 9 is a diagram showing a fifth example of the detection output that changes depending on the buried state.
FIG. 10 is a diagram showing detection outputs of a receiving antenna tool inserted into a deposit and a receiving antenna tool placed outside.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Deposit 2 ... Buried person 3 ... Steel furniture 4-6 ... Transmitting antenna tool 7-9 ... Reception antenna tool 10 ... Transmitter / receiver 11 ... Pen recorder 20 ... Transmitter 28 ... Changeover switch 30, 40, 50 ... Receiver 32 ... Subtractor 36 ... Detector 62 ... Unnecessary reflected wave cancellation signal generator 65 ... 90 degree phase shifter

Claims (7)

  A transmitting antenna device and a receiving antenna device having a structure in which a thin antenna is provided at the tip of a bowl-shaped support member are inserted into different positions of the deposit, and radio waves of a predetermined frequency are radiated from the transmitting antenna. A method of detecting a living object buried in the deposit from the characteristics of received radio waves, wherein one transmitting antenna tool and at least one receiving antenna tool are inserted at different positions of the deposit, and One receiving antenna tool that is not inserted into the deposit is arranged outside, and characteristics of radio waves received by the antennas of the plurality of receiving antenna tools are comprehensively evaluated to estimate the presence / absence of an embedded life object. Method for detecting buried life forms.   A transmitting antenna device and a receiving antenna device having a structure in which a thin antenna is provided at the tip of a bowl-shaped support member are inserted into different positions of the deposit, and radio waves of a predetermined frequency are radiated from the transmitting antenna. A method of detecting a living object buried in the deposit from the characteristics of received radio waves, wherein a plurality of transmitting antenna tools and at least one receiving antenna tool are inserted at different positions of the deposit, and further deposited. One receiving antenna tool that is not inserted into the object is arranged outside, and the transmission antennas of the plurality of transmitting antenna tools are sequentially transmitted, and the characteristics of the radio waves received by the antennas of the plurality of receiving antenna tools are comprehensively evaluated. A method for detecting a buried life form, wherein the existence of the buried life form is estimated.   3. The buried life form detecting method according to claim 1, wherein radio waves received by the antennas of the plurality of receiving antenna tools are detected in parallel and their output waveforms are output in parallel.   The antennas of the transmitting antenna device and the receiving antenna device have a gradual directivity in the length direction of their supporting members, and all the antenna devices inserted into the deposit are almost at one point in the deposit. The method for detecting an embedded life form according to any one of claims 1 to 3, characterized in that the direction is directed toward the surface.   A plurality of transmission antenna devices having a structure in which a thin antenna is provided at the tip of a bowl-shaped support member, a single transmitter that generates a high-frequency signal, and the transmission to any one of the plurality of transmission antenna devices A selector switch for selectively supplying the output of the vessel, at least one receiving antenna device to be inserted into the deposit having a structure in which a thin antenna is provided at the tip of the bowl-shaped support member, and the deposit A plurality of receivers connected to the plurality of reception antenna tools and detecting signals from the reception antenna tools, and output devices connected to the plurality of receivers. An embedded life form detecting device characterized by comprising:   Each of the reception circuits includes a first detection circuit that detects a phase of a reception signal using a reference signal of a transmission signal, and a second detection circuit that detects a phase of the reception signal using a signal that is 90 degrees out of phase with the reference signal of the transmission signal. The buried life form detecting apparatus according to claim 5, wherein:   An adjustment circuit that receives the branch signal of the transmission signal and adjusts the phase and amplitude thereof is provided, and each of the reception circuits subtracts the output of the adjustment circuit from the reception signal before the detection circuit. The buried life form detecting apparatus according to claim 5, further comprising a circuit that suppresses a signal corresponding to a reflected wave from the stationary object.

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