RU2509370C2 - Apparatus for searching for and locating people - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: method is carried out by mounting a visible range laser radiation source on the reflector of a receiving antenna, said source radiating along the median of the main lobe of its beam pattern. The apparatus for searching for and locating people consists of a radio transmitter 1 mounted on the person to be searched for, which includes series-connected first self-contained power supply 2, self-contained generator 3 and transmitting antenna with a quasi-isotropic beam pattern 4, as well as a radio receiver which includes a receiving antenna in form of a parabolic reflector 6, at the centre of which there is a hole 13 in which the laser radiation source 14 is inserted, a receiving head 8 connected by a flexible microwave coaxial cable 10 with an amplification and signal power indication unit 11, which is connected to a second power supply 12, and a rigid metal supporting arm 9.

EFFECT: high accuracy of indicating location of an object being searched for at any time of the day and in any weather conditions.

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Description

The invention relates to radio engineering and can be used to search and detect people, for example, lost in the mountains or forest, caught in a snow avalanche or under the ruins of buildings, based on the receipt of directional reception of specialized radio signals and based on the use of quasi-isotropic direction of radiation and narrow-focused reception of special signals.

The invention is known under the name “Method and device for remote location of people buried under extensive rubble” [1], the principle of which is based on the use of active radar technology and the measurement of Doppler frequency shift. The disadvantages of the invention are the difficulty of generating, processing back-received signals and the need to change the location of the transceiver unit.

A simpler device has the invention "A method for detecting living objects and a device for its implementation" [2], which allows you to register the respiratory rate and heart rate of a person carried in a thick layer of snow, based on the principles of standard radio telemetry. The disadvantage of the invention is that it does not have a narrow antenna, and therefore can only register the fact of preservation of human life without indicating its location.

The most simple in design and convenient to use can be considered a satellite television device for individual use, which has a long detection range of a microwave source and high accuracy of target designation in azimuth and elevation. A detailed description of the composition and principle of its operation is given in the section "An individual set of satellite television" on p.157-184 of the book [3].

According to [3], the device consists of a radio transmitter and a narrowly directed radiating antenna located on board an artificial satellite relay placed in a geostationary orbit at some fixed point at an altitude of 36,000 km above the equator, and a ground-based radio receiver set for individual use. The radio channel between the transmitter and the radio uses the standard three-centimeter band of 10.7-12.75 GHz radio waves, divided into two subbands: 10.6-10.75 GHz (lower) and 10.7-12.75 GHz (upper) subbands. With a radio transmitter power of several hundred watts and an oblique communication range of 40,000 km, the ground-based receiving complex provides high-quality reception of TV programs to a small-sized receiving antenna with a parabolic reflector with a diameter of only 0.5-0.6 m.

The advantage of this device, which is selected as a prototype, is that almost all elements of the radio receiving part of the complex can be used from among the nodes of serial industrial production that are part of the individual radio receiving complex [3, p.158-167, 179-184] :

a receiving antenna with a parabolic reflector having an offset (offset in the vertical plane) focus;

a receiving head containing a serially connected receiving horn antenna, the aperture of which is located in the offset focus of the reflector, a microwave bandpass amplifier, a frequency converter, and an intermediate frequency pre-amplifier of 0.95-2.15 GHz;

a received signal power indicator comprising a main intermediate frequency amplifier, a threshold device, and a direct arrow or LED signal power inductor at an intermediate frequency [9, 10].

According to [4, p. 9], domestic-made parabolic antennas with a diameter of 600 mm in the frequency range 10.7–12.75 GHz have a gain of 38 dB (6000 times) with a width of the main lobe of the radiation pattern at half power level of 2.9 °, which ensures high accuracy of pointing to the source in azimuth and elevation.

In turn, a large margin of gain in power at the carrier and intermediate frequencies of the receive-amplifier path guarantees a significant detection range of the radio signal, even taking into account energy losses in blockages and snow drifts.

However, an individual set of satellite television [4, p. 157-185] with all of these advantages, it has a drawback that does not allow to fully realize them. The reason is that fixing the direction of reception along the main lobe of the radiation pattern requires the use of an additional sight - a mechanical or optical and magnetic compass. And the greater the range, the more difficult it is to indicate the actual location of the radio transmitter located at the wanted person.

Another disadvantage of the prototype is the objective difficulty in determining the location of the detected object in the dark and in difficult weather conditions.

The required technical result is a significant increase in the accuracy of indicating the location of the wanted person in any meteorological conditions, at any time of the day can be achieved by installing on the reflector of the receiving antenna a laser source of the visible (green or red) wavelength range emitting along the median of the main lobe of its radiation pattern . At the same time, for the full realization of the high accuracy of the laser beam guidance, it is required that the maximum error of the angle mismatch between the directions to the radio emission source of the median of the main lobe of the radiation pattern and laser radiation be no more than ± 0.1º. Such a high requirement can be achieved if a hole is made in the geometric center of the parabolic reflector of the receiving antenna and the indicated source of laser radiation is installed in it by turning its longitudinal axis of symmetry, which coincides with the direction of radiation, upward in a vertical plane at an angle α, where α is the angle of displacement focus for the selected offset antenna.

The choice of the geometric center of the parabolic reflector as the location of the laser radiation source is explained by the high rigidity of this part of the reflector, which is not subject to external influences, unlike the periphery of the reflector. In addition, the hole in the center of the reflector allows you to firmly fix that desired direction of radiation through the use of epoxy glue or soldering with low-temperature solder.

The technical nature of the claimed device is illustrated by the drawing shown in figure 1, where the following notation is used.

1. Small-sized, low-power microwave radio transmitter located in a person at risk of being in a critical situation.

2. The first self-contained power source of the radio transmitter.

3. Microwave generator.

4. A microwave emitting antenna with a quasi-isotropic radiation pattern.

5. The direction of radiation of the radio transmitter.

6. The reflector of the receiving antenna, where

F1 is the position of the direct focus on the longitudinal axis of symmetry of the OX reflector;

F2 - position of the offset (offset) focus of the reflector;

α - offset angle of focus shift of the reflector in the vertical plane.

7. The direction of re-emission of the signal 5 received by the reflector 6.

8. The receiving head.

9. Hard metal bracket.

10. Flexible coaxial microwave cable.

11. Block amplification and induction of signal power at an intermediate frequency of 0.95-2.15 GHz.

12. The second autonomous power source.

13. The hole in the geometric center of the reflector 6.

14. The source of visible laser radiation, equipped with a built-in power source.

15. The direction of visible laser radiation.

The interconnection of the elements of the device is as follows. The first autonomous power supply 2 of the radio transmitter 1 is connected to a microwave oscillator 3, the load of which is a radiating antenna 4. The aperture of the horn antenna (horn) of the receiving head 8 is located in the offset focal plane F2. Fixing the position of the aperture in the focal plane F2 and the direction of the longitudinal axis of symmetry of the head 8 at an angle α relative to the longitudinal axis of symmetry of the reflector 6 in the vertical plane is carried out using a rigid metal bracket 9, one end of which is mounted on the outer surface of the reflector 6, and the other covers the cylindrical body of the head 8, the output of which is connected via a flexible coaxial microwave cable 10 to the input of the amplification and signal power display unit 11 at an intermediate frequency of 0.95-2.15 GHz, connected about the second stand-alone power source 12. An additional hole is made in the geometric center of the reflector, in which the laser radiation source 14 of the visible wavelength range is rigidly fixed so that its longitudinal axis of symmetry is at the angle of -α to the longitudinal axis of symmetry of the reflector in the bottom of the vertical plane 6.

The functioning of the proposed device is as follows. The radio transmitter 1 is located in a person who runs the risk of being in one of the emergency situations mentioned above. When a danger occurs, the first autonomous power source 2 is turned on, after which the self-oscillator 3 is equipped with an antenna with a quasi-isotropic radiation pattern 4. The radio wave 5 emitted by the antenna propagates in space and reaches the inner surface of the receive antenna parabolic reflector 6. Next, the radio wave reflected from the reflector 6 7 is focused in the plane of the aperture of the horn of the receiving head 8, where it is converted into microwave current, after which it passes through ilitelno-conversion path of the head 8, taking the standard value of the intermediate frequency 0,95-2,15 GHz. Next, the signal at an intermediate frequency from the output of the receiving head through a flexible coaxial microwave cable 10 is fed to the input of an amplifier-indicator unit 11 connected to a second autonomous power source 12.

Currently, the indicator of block 11 is performed in two versions: with an arrow and discrete LED multi-bit indication of signal strength. The fact of signal detection is recorded by an acoustic signal (buzzer).

The maximum of the received signal will be observed when the emitted wave 5 is directed along the median of the main lobe of the radiation pattern of the receiving antenna with a width of about 3.0º at half power. This direction is deviated from the longitudinal axis of symmetry of the reflector by an angle α and is visually observed and fixed by visible laser radiation.

The exact direction to the radiation source is fixed by the maximum deflection of the arrow of the indicator of the first or by the maximum number of luminous LEDs of the indicator of the second type. The divergence angle of the beam of the green solid-state laser is not more than 0.1-0.2º, which makes it possible to reduce the diameter of the zone of uncertainty of the search for an object by 15-20 times compared with the zone determined by the radio wave, regardless of the time of day or weather conditions.

Thus, highly focused green or red laser radiation indicates with high accuracy the direction to the microwave source, which is especially noticeable in the dark. If there are no additional obstacles to the propagation of laser radiation, then the laser spot on the ground will indicate the location of the search object. If there is interference, fix the azimuth and elevation angle of the direction to the search object.

Conducted preliminary research in the field of the current state of satellite television technology showed fairly simple and inexpensive options for implementing the claimed invention, which is confirmed by the following example of manufacturing a model of the claimed device.

The radio transmitter unit operating in the economical mode of pulse-amplitude modulation is made according to the principle circuit, which includes the following cascades:

pulse generator of a melodic sequence on an integrated circuit UMS 8;

electronic modulator key on two bipolar transistors KTZ 102K (n-p-n) and KTZ 107K (p-n-p);

microwave oscillator with transistor KT647A (n-p-n), the resonant circuit of which is simultaneously a radiating single-turn circular loop antenna with a diameter of 9 mm;

The first autonomous power source is a galvanic battery with an initial voltage of 9.0 V and a capacity of 1200 mAh for the alkaline version of Rubin. The consumed current ranges from 3-10 mA depending on the duration of the pulses (20-40 μs) and the frequency of their repetition (3-4 kHz), which is determined by the nature of the selected melody. To indicate the inclusion of the device, a bright red LED is used, the current consumption of which is limited to 0.5 mA by means of a 12 kΩ resistor connected to the power bus. The oscillatory power in the wave of 2.7 cm supplied to the ring antenna is 30 mW, the radiated power is 15 mW.

Structurally, the electrical circuit of transmitter 1 is made on two printed circuit boards: one is a pulse sequence generator with an electronic key and a voltage regulator, the second is a self-oscillator with a single-turn loop antenna in the shape of a circle ⌀ 9 mm. These boards together with the battery are installed inside a standard case made of impact-resistant plastic with external dimensions of 98 × 70 × 24 mm. The power-on LED is displayed on the front of the chassis. The power switch is located on the side. Total weight less than 100 grams. Transmitter operability is maintained when the supply voltage is reduced to 7.0 V.

The radiation pattern of the ring antenna 4 of the radio transmitter 1 at a wavelength of 2.7 cm, obtained experimentally, indicates a uniform radiation pattern: the dips reach the level of 0.5-0.7 (minus 3-6 dB) relative to the maximum of 1.0 for all azimuth values 0º-360º. Therefore, we can consider the radiation pattern of the transmitter 1 quasi-isotropic.

In [4, p. 9], detailed basic technical specifications and the appearance of small-sized offset receiving antennas with a diameter of 0.6 m, 0.9 m and 1.2 m used in individual satellite television of domestic production are given:

operating frequency band 10.7-12.75 GHz;

gain of 35.0, 38.5 and 41.0 dB, respectively;

width of the main lobe of the radiation pattern at half power level 2.9º;

the level of the side lobes of the receive radiation pattern minus 25 dB;

the level of cross-polarization minus 25-30 dB.

The technical characteristics of the widespread offset antenna F 0.55 STV-0.55-11 [9] indicate that for it the offset angle α = 19.65º, the width of the main lobe of the receive radiation pattern 3.3º, gain 34.5 dB, weight without suspension 2.6 kg with a diameter of 55 cm.

The receiving heads (converters) manufactured by the PRC are widely used in our country, information on the most famous of them is given below.

The main technical characteristics of the single-channel universal receiving head (converter) GSLF-51E manufactured by General Satellite (China) [7]:

range of received frequencies 11.7-12.7 GHz;

intermediate frequency 950-2000 MHz;

local oscillator frequency 10.75 GHz;

noise figure 0.3 dB;

gain of 50-60 dB;

right-handed polarization of the signal at a supply voltage of 11-14 V;

left-handed polarization of the signal at a supply voltage of 16-20 V;

cross-polarization suppression 25 dB;

attenuation of the mirror channel 40 dB;

current consumption 90 mA;

output coaxial connector 75 Ohm, socket;

spurious emission level minus 60 dB;

operating temperature range from -40ºС to + 65ºС;

weight 220 g

Technical characteristics of the receiving head (converter) U-011 manufactured by Sevensky (China) are similar to those given in [10]. The difference lies in establishing the reception mode of any polarization, left-side and right-side at the same time (circular polarization), due to loss of gain by 3 dB, as well as in the electronic way of switching the range of received frequencies:

10.7-11.7 GHz with a supply voltage of 11-14 V;

11.7-12.75 GHz with a voltage of 16-20 V.

The head is equipped with two local oscillators operating at different frequencies: 9.75 GHz and 10.60 GHz. Their switching is carried out by changing the supply voltage.

A short list of characteristics of additional indicators of the received signal power called Satellite Finder (PRC) with arrow and LED indication of the signal power level, included between the output of the receiving head and the input of the television receiver, given in [9, 10], indicate that:

intermediate frequency 950-2400 MHz for the ASF 304 and 950-2150 MHz for the SF-12;

maximum input signal level minus 10 dB · mW;

supply voltage 13-18 V.

Instructions for the user of the device with arrow indicators [9] indicate that the scale of the device has 100 divisions in increments of 0.05 V, the deviation is within 0-5 V. The gain at the intermediate frequency is controlled by a variable resistor in the range from 20 to 30 dB. Current consumption 20 mA, operating voltage 13-18 V.

A similar instruction with a discrete LED indication [10] indicates that the indicator contains 6 red LEDs with a discrete response step of 0.5 V. The maximum input signal level is minus 10 dB relative to the level of 1 mW. Current consumption 20 mA, adjustable gain level (setting the threshold for the first LED) 20-30 dB.

The normal operation of both devices [9, 10] is ensured with a ratio of signal powers and internal thermal noise of 15 dB (30 times). Guaranteed noise figure of the receiving head is less than one.

In the described device layout, a laser pointer is used as a source of laser radiation in the visible wavelength range.

Currently, laser pointers of green and red glow with a power of 1 to 100 mW are widely distributed. The best results were obtained using a laser pointer manufactured by the People's Republic of China with a nominal radiation power of 50 mW at a wavelength of 532 ± 10 nm according to the 21 CFR standard. Its length is 165 mm, diameter 15 mm, weight 150 g. Powered by two alkaline AAA elements with a total voltage of 3.0 V, built into the pointer body.

The hole 13 in the geometric center O of the reflector 6 has a diameter of 18 mm A metal sleeve of copper is inserted into it, the diameters of which are ⌀18 × 16 mm. A laser pointer 14 without play is inserted into this sleeve. The angle of inclination α = 19.7º of the sleeve is fixed by soldering with POS-60C solder on both sides of the steel sheet of reflector 6 with a thickness of 2.0 mm.

The second stand-alone power source 12 is a standard cartridge for 8 AA elements. In this case, 8 battery cells with a capacity of 2600 mAh and an initial voltage of 1.2 V were used. Charging current 260 mA in 12 hours.

The total current consumption of the device with an arrow indication is 105 mA, with LED - 110 mA in the absence of a signal and up to 125 mA at a maximum signal. Thus, when using a battery with a capacity of 2600 mAh when discharging its energy by 85%, the device is able to work for a total of 16 to 20 hours.

Both versions of the amplifier-indicator unit 11 were placed together with power sources - rechargeable batteries in a standard high-impact plastic case with external dimensions of 200 × 100 × 60 mm.

A field test of both device variants confirmed that in manual aiming mode they provide a narrow reception pattern along the main lobe of the receiving antenna within 2.5º-3.5º both in azimuth 0º-360º and in elevation ± 80º, which provides an overview and search from the bottom of the gorge to the mountain peak.

The location of the object is indicated using a laser pointer in the daytime at a distance of up to 400 m, at night - up to 2 km.

The practice of pilot operation of both options revealed that it is more convenient to use an LED indicator than a pointer.

During field tests of the device’s model, it was necessary to additionally install three handles on the external surface of the parabolic reflector, two of which were installed at the intersection of the horizontal axis of symmetry, and the third in the upper part vertically. The latter is intended for ease of movement, and the other two are for searching in azimuth and elevation.

Information sources

1. RU No. 2313108, 2007.

2. RU No. 2111119, 1999.

3. All about antennas. Individual antennas: structures, installations, satellite dishes. - M .: ONIX, Center for Human Values, 2008. - 240 p.

4. Satellite dishes. Catalog of the company "Squirrel". Part 1. - M .: Belka, 2005 .-- 114 p.

5. Passport. Antenna F 0.55 STV - 0.55 - 11 AUM. - Ulyanovsk, OJSC AlMet, 2009. - 4 p.

6. Brief installation instructions for the SEVENSKY satellite dish. - M .: CJSC National Satellite Company, 2009. - 4 p.

7. General Satellite Corp., Ltd. // www.general-satellite.com. - 2 p.

8. Sevensky. Chen Mind Electronics Technology Co., Ltd, China, 2009. - 2 p.

9. Satellite Finder. Atlanta Satellite Systems. // www.atlanta-digital.com. - 2 p.

10. Satellite Finder SF - 12. Euston. // www.euston.com. - 2 p.

Claims (1)

A device for searching and determining the location of people, consisting of a radio transmitter 1 located in a person to be searched, including a first autonomous power source 2, a self-oscillator 3, operating in the microwave range of radio waves 10.5-12.75 GHz, connected in series , and a transmitting antenna with a quasi-isotropic radiation pattern 4, as well as a radio receiver in the hands of the operator of the hunt group and including a receiving antenna in the form of a parabolic reflector 6, in the offset plane focus F2 of which the aperture of the horn of the receiving head 8 is located, fixing the direction of longitudinal symmetry of which at an angle α to the longitudinal axis of symmetry of the reflector 6 in the upper part of the vertical plane is carried out by a rigid metal bracket 9, one end of which is fixed to the outer surface of the reflector 6, and the other covers a cylindrical body the receiving head 8, while the output of the head 8 is connected by a flexible coaxial microwave cable 10 to the input of the amplification and indication unit 11 of the signal at an intermediate frequency of 0.95-2.15 GG connected to the second power source 12, characterized in that a hole 13 is made in the geometric center of the reflector 6, in which the laser radiation source 14 of the visible wavelength range is mounted and rigidly fixed so that the longitudinal axis of symmetry of the laser radiation source 14 is in the upper part vertical plane at an angle -α to the longitudinal axis of symmetry of the reflector 6.