Title of Invention

"AN EQUIPMENT FOR THE REMOTE DETECTION OF TRAPPED ANIMATE SUBJECTS"

Abstract

An equipment which can detect a person buried under rubble or behind a barrier is described. The equipment has been built on the principle of backscattering of electromagnetic waves by the body of an animate subject, which when illuminated by a radio beam of suitable frequency, a part of the electromagnetic (em) energy is backscattered and it travels up the rubble where it is picked up by the antenna at the top of the rubble. The signal so picked up carries the Doppler modulation in phase and amplitude due to the movement of the chest region / body movement. The signal is processed by a receiver. The receiver displays either the periodic breathing cycles and/or sudden changes in steady level of signal as the case may be, to indicate the presence of the trapped animate subject under the rubble.

Full Text

The present invention relates to an equipment for the remote detection of trapped animate subjects. The present invention particularly relates to electronic equipment for remote detection of animate subjects such as humans, animals and birds. More particularly the invention relates to an electronic equipment capable of detecting animate subjects trapped under rubble or behind a wall by using electromagnetic backscattering technique. Every year many earthquakes of varying intensity take place in the world leading to destruction of property and loss of lives. Quick rescue of trapped persons under the earthquake rubble is crucial for saving their lives. This has been a challenging problem for the inventors. The conventional methods of detections like sniffer dogs and lowering a sensitive microphone or a infrared sensor are not without their associated problems. A sniffer dog takes longer time and at times, may even miss the trapped person. The microphone detects any feeble moaning of the victim. When the victim is unconscious it will be missing the person trapped. The infra red head detects the trapped person by its body heat. Both these techniques need a cable to be lowered down to the close proximity of the victim which may not always be possible due to clearance problem through the debris. The present invention is capable of overcoming these difficulties by using an electromagnetic technique which is totally remote. In the prior art, various techniques are available for detection of animate subjects trapped under a rubble or in debris. Such techniques include use of infra red rays to sense warmth of a body or sensing of moans by means of a proximity of ultra sensitive microphones to the trapped animate subjects. The first technique necessarily needs to have the physical touch of a sensing device such as a thermistor with the trapped subject to be able to detect the same. The other technique of sensing of moans also needs to have the sensing element namely the sensitive microphone as close to the trapped subjects as possible. Both the above mentioned techniques are limited in their use for detecting a trapped animate subject only if the sensing element is kept very dose to the target which may not be possible under normal practical conditions of disasters. Further, neither of the technique is usable for detection of subjects for use in establishing and monitoring security conditions. To address these problems, it is essential to have an equipment which can be used remotely without the need for any physical proximity of any part of equipment with the subject to be detected. This is achievable by the use of back scattering of electromagnetic waves from the subject to be detected. Reference may be made to disclosure by C Lin in , Proc. IEEE, vol. - 63, 1975, p. 1530 wherein the researcher has described use of X band frequencies to detect remotely the respiration of man and animal by directing a horn towards the body part of interest. This system is usable only for such applications where there is no solid object in the path of the X band radiation. In yet another disclosure in Microwave Journal, May 1978, pp. 69- 72.]. 1978, by Donald W. Griffin, microwaves were used in interferometry mode to detect body part movements including breathing/heart beats remotely, in such studies generally X band frequencies were used. In another disclosure in IRE Transactions on Microwave Theory and Techniques, vol. MTT-27, No. 6, June 1979, pp. 618 - 20]. By [James C. Lin et. al, S band frequency was used to obtain Apex Cardiograph. In this disclosure a standard laboratory signal generator was used as the electromagnetic source. A vector voltmeter and a directional coupler were used as receiver. The researchers were able to detect ventricular activities of a human heart. The S band use has the limitation that there is a very large attenuation of the signal due to high frequency in the range of 2.5GHz to 5GHz. In view of this inherent large attenuation there is a limitation on recovery of weak signals from subjects buried under or behind solid material. Reference may be made to yet another disclosure in IEEE Transactions on Biomedical Engineering, vol. BME - 33, No. 7, July 1986, pp. 697-701]. wherein Kun - Mun - Chen et. al used microwaves at X band to detect heart beats/breathing from as far as 30 metres by building an equipments using microwave systems/subsystems. The equipment was also used for detecting these parameters of a person behind a barrier like brick wall. The detection was found to be of poor quality due to excessive attenuation at this frequency The main objective of the present invention is to provide an equipment for the remote detection of trapped animate subjects which obviates the above mentioned drawbacks. Another object of the present invention is to provide an equipment that can, without any physical contact with the animate subject, detect the presence of the trapped subject under rubble or behind a barrier made of construction material like cement, brick,wood. Yet another objective of the present invention is to facilitate detection of animate subjects trapped in a room on fire. A further objective of the present invention is to detect an animate subject which has fallen in a crevasse in high altitude areas where there is dry snow (no melting of snow is taking place leading to liquid water formation) A still further another objective of the present invention is to detect persons hiding inside a room for security applications. A further object of the present invention is to provide an equipment which is portable. An equipment which can detect a person buried under rubble or behind a barrier is described. The equipment has been built on the principle of back scattering of electromagnetic waves by the body of an animate subject, which when illuminated by a radio beam of suitable frequency, a part of the electromagnetic (em) energy is back scattered and it travels up the rubble where it is picked up by the antenna at the top of the rubble. The signal so picked up carries the Doppler modulation in phase and amplitude due to the movement of the chest region/body movement. The signal is processed by a receiver. The receiver displays either the periodic breathing cycles and /or sudden changes in steady level of signal as the case may be, to indicate the presence of the trapped animate subject under the rubble. In the drawings accompanying the specifications Figure 1 shows the block diagram of the equipment of the present invention, wherein 'O* is an animate subject. (1) is a phase locked RF Source. (2) is an RF Amplifier. (3) is a Directional coupler. (4) is circulator. (5) is an antenna. (6) is a Directional coupler. (7) is an attenuator. (8) is phase translator. (9) is a directional coupler. (10) is a composite of DC Amplifier, Voltage Translator and AD converter. (11) is a low noise amplifier. (12) is a microprocessor having ports A,B, C. (13) is a detector, (14) is a directional coupler, (15) is a double balanced mixer having IF and RF ports. (16) is an Operational amplifier. (17) is a low pass filter. (18) is a recording/display device and (19) is the output pattern. Figure 2 shows the diagram of a breathing cycle as detected . Accordingly the present invention provides an equipment for the remote detection of trapped animate subjects which comprises: a phase locked radio frequency generating source (1), the output of the said source being power amplified by an RF amplifier (2), the amplified power being branched into two paths by a directional coupler (3), one branched path leading to a circulator (4)connected to an antenna (5) capable of transmitting and receiving RF signal to and from an animate subject O, the second branched path from the said directional coupler (3) leading to another directional coupler (6) further giving two branched outputs, one output of the said directional coupler (6) being fed to a programmable step attenuator (7) connected to port B of a microprocessor (12) through the switching control of a programmable phase translator (8), the said programmable step attenuator (7) being also connected to port C of the said microprocessor through a composite DC amplifier, voltage translator and A-D converter (10), the output of the programmable phase translator (8) and the signal returned from the animate subject O to the antenna (5) being fed to a directional coupler (9) the output from the said directional coupler (9) being fed to a low noise amplifier (11), the amplified output of the said amplifier(11) being fed to another directional coupler (14) providing two branched outputs, one branched output being fed to a detector (13) capable of converting the radio frequency signal into dc signal, this detector (13) output being fed to a port A of the microprocessor (12), the second branched output of the said directional coupler (14) being fed to the RF port of a double balanced mixer (15), the said double balanced mixer receiving a second output from the said directional coupler (6), the output from the IF port of the said double balanced mixer (15) being routed through an operational amplifier(16) and a low pass filter (17) to a recording/display device (18), outputting the final wave form (19). In an embodiment of the present invention the radio frequency used may be in a frequency range of 1-2 GHz. In another embodiment of the present invention the radio frequency power used maybe in a range of 100m Watts to 2 Watts. In yet another embodiment of the present invention the antenna used may be of any geometry having a planar aperture, such as pyramidal horn, micro strip planar array In still another embodiment of the present invention the recording/display device used may be such as an oscilloscope, a strip chart recorder, a digital/analogue meter. In a further embodiment of the present invention the antenna used may be placed in any orientation such as vertically above, horizontally axially with the axis pointing towards the subject. The equipment functions in the following manner described particularly with reference to a buried life body under a stone rubble. This however does not restrict the use of the device in any other orientation. A horn antenna is placed on the top of the rubble illuminates the body including the chest region by its radiating electromagnetic (e m) field. A part of the electromagnetic field is reflected back. This reflected field carries the phase modulation introduced by the expanding and contracting chest wall of the human subject. When received by the same horn antenna at the top of the rubble the phase modulation so introduced is processed by a receiver. The detected signal which is a slowly varying dc signal is in perfect synchronism with the breathing cycle of the human subject. Thus the signal so detected acts as an indicator of life below the rubble. This technique works even if the person under the rubble is unconscious. In addition, if the person is not unconscious he will obviously move his hands or body as a whole to extricate himself from the rubble. This will introduce large and sudden changes in the received signal which will also indicate the presence of a person alive under the rubble. Thus both or any one of these indications can be used as life indicator for a trapped person. The horn antenna / any other type of antenna is to be placed on the surface of the rubble. A part of the power transmitted by the antenna travels down the rubble and strikes the chest region or any other part of the of the body which is in motion. The power reflected by the chest region/body movement, travels up through the rubble. The emerging reflected power is intercepted by the same antenna on the rubble surface. The changes introduced by the movement of the chest wall is processed by the receiver and the indicates the presence of a victim under the rubble by displaying either breathing cycles or sudden jumps in signal. A block diagram of the equipment is shown in Figure 1. A Phase Locked Source (1) generates the required radio frequency power. This power is further amplified by an Amplifier (2). Amplified power is then branched into two paths by a Directional Coupler (3). Straight path leads to a device called Circulator (4). Use of the circulator enables one to use the same antenna (5) for both transmission and reception. The power from the circulator is fed to the Antenna (5). The second path from the directional coupler (3) leads to another Directional Coupler (6). The strait arm of the coupler (6) goes to a Programmable Step Attenuator (7) and then on to the Programmable Phase Translator (8). The switching control of the phase translator (8) goes directly to B port of the microprocessor (12). The body returned signal from the antenna (5) and the phase translated signal from (8) are added in the Directional Coupler (9). Output of this directional coupler (9) is fed to a Low Noise Amplifier (11). Amplified output of this amplifier(11) goes to another Directional Coupler (14). The side arm of this coupler(14) goes to a Detector (13) to convert the rf into dc. The detector output is fed to the port A of the Microprocessor (12). The strait arm of the coupler (14) goes to the RF port of a Double Balanced Mixer ( 15). The output of the side arm of the directional coupler (6) is fed to the local oscillator port of the double balanced mixer (15). The switching control of the attenuator (7) is fed to the C port of the Microprocessor (12) through the Translator (10). The IF port of the double balanced mixer (15) fed to an Operational Amplifier (16). The output of this amplifier (16) goes through a Low Pass Filter (17) to a recording/viewing device (18). The recording device could be a chart recorder. The viewing device could be an oscilloscope. The breathing is wave form (19). When a human subject trapped under rubble or behind a wall is illuminated by an electromagnetic wave of suitable frequency from the top of the rubble, a part of the wave power backscattered by the victim's body is Doppler modulated by his chest/body movement. The Doppler modulated backscattered wave travels up the rubble where it is picked up by an antenna placed on the surface of the rubble. The Doppler modulation in phase/amplitude is processed by a receiver and the presence of the victim is indicated by displaying his breathing cycle/signal jumps due to body movement. The novelty of the invention lies in its capability of penetrating a barrier and indicating the presence of a life form across the said barrier. This allows a remote detection of trapped animate subjects. The novelty has been achieved due to the non obvious inventive steps of signal generation and reception in the 1-2 GHz electromagnetic spectrum at a power in the range of 100mWatts to 2 Watts source radiation coupled with the principle of back scattering of electromagnetic radiation. The following examples are given by way of illustration only and should not be construed to limit the scope of the invention. Example-1 A fibre glass tank was taken and filled with rubble of stones and concrete mixture to a depth of 50 cm. A horn antenna was placed over the rubble at a distance of 50 cm. The antenna was coupled to the device . A human subject was positioned below the fibre glass tank as an object to be detected by the device of the invention. The human subject was 1 metre below the bottom of the tank The horn was excited by an RF source of 1.8 GHhz. at a power level of 140 mWatts. The breathing cycle of the subject trace buried under the concrete rubble, as recorded on an oscilloscopic is shown in the figure 2. The trace of breathing cycles are almost 6 seconds apart, typical of a human subject. Example - 2 A human subject was placed behind a 20 cms. thick wall separating two rooms. A pyramidal horn antenna clamped on a tripod and fixed on a trolley was connected to the equipment and was moved in smooth manner along a line. The distance of the horn antenna was kept 1 metre from the wall. During the motion of the trolley the output indicator on the meter on the equipment showed irregular jerky trace due to the movement of the body parts of the human being as soon as the antenna faced the human subject. This irregular jerky trace is indicative of some object across the wall and started showing breathing cycles which essentially represents the breathing cycle of a human being. The main advantages of the invention are 1.The equipment does not require any physical connection with the subject. 2. The equipment can also be used to detect a person trapped in fire inside a room by rescue persons from a safe distance. 3. The equipment can also be used to detect a person trapped in a crevasse / snow avalanche in high altitudes where there is no melting of snow leading to liquid water formation. 4. The equipment can be used to detect persons hiding inside a room. 5. The equipment is portable and can be easily taken anywhere. We claim: 1. An equipment for the remote detection of trapped animate subjects which comprises: a phase locked radio frequency generating source (1), the output of the said source being power amplified by an RF amplifier (2), the amplified power being branched into two paths by a directional coupler (3), one branched path leading to a circulator (4)connected to an antenna (5) capable of transmitting and receiving RF signal to and from an animate subject O, the second branched path from the said directional coupler (3) leading to another directional coupler (6) further giving two branched outputs, one output of the said directional coupler (6) being fed to a programmable step attenuator (7) connected to port B of a microprocessor (12) through the switching control of a programmable phase translator (8), the said programmable step attenuator (7) being also connected to port C of the said microprocessor through a composite DC amplifier, voltage translator and A-D converter (10), the output of the programmable phase translator (8) and the signal returned from the animate subject 0 to the antenna (5) being fed to a directional coupler (9) the output from the said directional coupler (9) being fed to a low noise amplifier (11) , the amplified output of the said amplifier(11) being fed to another directional coupler (14) providing two branched outputs, one branched output being fed to a detector (13) capable of converting the radio frequency signal into dc signal, this detector (13) output being fed to a port A of the microprocessor (12), the second branched output of the said directional coupler (14) being fed to the RF port of a double balanced mixer (15), the said double balanced mixer receiving a second output from the said directional coupler (6), the output from the IF port of the said double balanced mixer (15) being routed through an (16) operational amplifier/and a low pass filter (17) to a recording/display device (18), outputting the final wave form (19). 2. An equipment as claimed in claim 1, wherein the radio frequency used is in a frequency range of 1-2 GHz 3. An equipment as claimed in claims 1 -2, wherein the radio frequency power used is in a range of 100mWatts to 2 Watts. 4. An equipment as claimed in claims 1 - 3, wherein the antenna used is of any geometry having a planar aperture, such as pyramidal horn, micro strip planar array 5. An equipment as claimed in claims 1-4, wherein the recording/display device used is an oscilloscope, a strip chart recorder, a digital/analog meter. 6. An equipment as claimed in claims 1-5, wherein the antenna used is placed in any orientation such as vertically above, horizontally axially with the axis pointing towards the subject. 7. An equipment for the remote detection of trapped animate subjects electronic—remote—dotoction substantially as herein described with reference to the drawings and examples accompanying this specification.

Documents:

281-DEL-2002-Abstract-07-05-2008.pdf

281-del-2002-abstract.pdf

281-DEL-2002-Claims-07-05-2008.pdf

281-del-2002-claims.pdf

281-DEL-2002-Correspondence-Others-07-05-2008.pdf

281-del-2002-correspondence-others.pdf

281-DEL-2002-Correspondence-PO.pdf

281-DEL-2002-Description (Complete)-07-05-2008.pdf

281-DEL-2002-Description (Complete).pdf

281-del-2002-drawings.pdf

281-DEL-2002-Form-1-07-05-2008.pdf

281-del-2002-form-1.pdf

281-del-2002-form-18.pdf

281-DEL-2002-Form-2-07-05-2008.pdf

281-del-2002-form-2.pdf

281-DEL-2002-Form-3-07-05-2008.pdf

281-del-2002-form-3.pdf