RU2282870C1 - Emergency radio buoy - Google Patents

Abstract

FIELD: radio engineering, applicable for transmission of information and determination of co-ordinates of objects suffering a distress.

SUBSTANCE: the emergency radio buoy has a unit for input of the radio buoy activization signal, permanent storage unit, two quartz master oscillators, control voltage driver, two power amplifiers, duplexer, antenna, time code driver, unit of frequency dividers, parallel-to-serial code converter, modulating signal driver, phase detector, two adders, direct current amplifier, two phase manipulators, X2 frequency divider, frequency divider with coefficient 40, two modulating code drivers, controlled generator.

EFFECT: enhanced reliability of transmission of alarm information and enhanced accuracy of determination of co-ordinates of objects suffering a distress.

5 dwg

Description

The proposed emergency beacon relates to radio engineering and can be used to transmit information and determine the coordinates of objects in distress in the space rescue system for emergency aircraft and COSPAS / SARSAT ships.

Known emergency beacon in the form of a radar transmitter, which contains a power supply, a switching and modulation unit, a transmitter with amplitude modulation, a transmitter with frequency modulation and an antenna. The switching and modulation unit controls the alternate operation of the transmitters with a silence pause after each transmission. The frequency modulated signal allows you to quickly detect and locate a distressed object by the marine coastal services or a ship located at a certain distance from the accident site. Signals with amplitude modulation make it possible to detect disaster victims on board the aircraft (French patent No. 2535065, G 01 S 1/68, 1984).

A disadvantage of the known technical solution is the inability to use an emergency beacon in the space rescue system, since it does not generate a signal at a frequency of 406 MHz.

A known emergency beacon containing a beacon activation signal input block, a permanent memory block, a first adder, a first, a second driving crystal oscillators, an amplitude modulator, a first, a second power amplifier, a control voltage driver, a duplexer, an antenna, a time code generator, a frequency divider unit, parallel to serial converter, modulator, phase detector, second adder, DC amplifier, control generator, frequency multiplier by d VA and a frequency divider with a coefficient of 40. The specified emergency beacon is selected as a prototype and provides automatic inclusion of the beacon according to the readings of emergency sensors with registration of the time elapsed since the accident (RF patent No. 2060512, G 01 S 1/68, 1996).

A disadvantage of the known emergency beacon is the inability to use complex signals with phase shift keying, which can improve the reliability of the transmission of alarm information and the accuracy of determining the coordinates of objects in distress.

An object of the invention is to increase the reliability of the transmission of alarming information and the accuracy of determining the coordinates of objects in distress by using complex signals with phase shift keying.

The problem is solved in that in an emergency beacon containing a beacon activation signal input unit, a permanent memory unit, first and second adders, first and second driving crystal oscillators, first and second power amplifiers, a control voltage shaper, a duplexer, an antenna, a time code shaper , block of frequency dividers, parallel-to-serial code converter, modulating signal generator, phase detector, DC amplifier, control generator, frequency multiplier two and a frequency divider with a division factor of 40, while the first output of the beacon activation signal input block is connected to the input of the permanent memory block, n outputs of which are connected to the first n inputs of the first adder, with the first input of the time code generator, the second output of the activation signal input block the beacon is connected to the second input of the first adder, the outputs of the first and second power amplifiers are connected through the duplexer to the antenna, the output of the second master crystal oscillator is connected to the input of the frequency divider block, the first output of which is connected to the second input of the time code generator, the n outputs of which are connected to the third n inputs of the first adder, the n outputs of which are connected to the first n inputs of the parallel code to serial converter, the second input of which is connected to the second output of the frequency divider block, the third n outputs which is connected to n inputs of the modulating signal driver, the output of the parallel-to-serial code converter through the control voltage generator is connected to the first second input about the adder, the second input of which is connected to the output of the phase detector, a DC amplifier, a controlled generator and a frequency multiplier by two are connected in series to the output of the second adder, the output of the controlled generator through a frequency divider with a division factor of 40 is connected to the first input of the phase detector, the second input which is connected to the output of the second master crystal oscillator, the first and second modulators of the modulating code, the first and second phase manipulators are introduced, and the output of the the first modulator code driver and the first phase manipulator, the second input of which is connected to the output of the first master crystal oscillator, the third input is connected to the first output of the beacon activation signal input unit, and the output is connected to the input of the first power amplifier, to the output of the control shaper the voltage is sequentially connected to the second driver of the modulating code, the second phase manipulator, the second input of which is connected to the output of the frequency divider into two, and the output is connected to the input of the second power amplifier.

The structural diagram of the proposed emergency beacon is presented in figure 1. The block diagram of the beacon activation signal input block is shown in FIG. The block diagram of the modulator signal is presented in figure 3. The block diagram of the time code generator is shown in FIG. Timing diagrams explaining the principle of operation of the beacon are shown in Fig.5.

The emergency beacon contains a beacon activation signal input block 1, a permanent beacon memory block 2, a first adder 3, the second input of which is connected to the second output of the beacon activation signal input block 1, a parallel to serial code converter 14, the second input of which is connected to the first output of the block 13 frequency dividers, control voltage driver 8, second adder 17, DC amplifier 18, controlled generator 19, frequency multiplier 20 by two, second phase manipulator 34, second whose first input, through the second modulator code generator 33, is connected to the output of the control voltage generator 8, a second power amplifier 9, a duplexer 10, and an antenna 11. A frequency divider 21 with a division coefficient 40 and a phase detector 16 are connected in series to the output of the controlled oscillator 19, the second input of which connected to the output of the second master crystal oscillator 7, and the output is connected to the second input of the adder 17. The second input of the shaper 12 is connected to the second output of the block 13 of the frequency dividers, the third output of which one with a first output of one input activation signal beacon. A block 13 of frequency dividers, a modulating signal driver 15, a first modulating code generator 32, a first phase manipulator 5, the second input of which is connected to the output of the first master crystal oscillator 4, and the third input to the first output of block 1 are connected to the output of the second master quartz oscillator 7 in series. input signal activation beacon, and the first power amplifier 6, the output of which is connected to the second input of the duplexer 10.

Block 1 input signal activation of the beacon (figure 2) contains a block 22 of sensors for automatic activation. A manual power button 23, a programmable read-only memory 24, two operational memory elements 25 and 26, an OR element 27.

The modulating signal generator 15 (Fig. 3) comprises a counter 28 and a multiplexer 29, the four inputs of the multiplexer 29 and the input of the counter 28 being connected to the corresponding inputs of the multiplexer 29, the output of which is the output of the modulating signal generator 15.

The time code generator 12 (Fig. 4) comprises a frequency divider 30 with a division ratio of 2700 and a counter 31, the input of the frequency divider 30 being the signal input from the first output of the emergency beacon frequency divider block 13, the output of the frequency divider 30 connected to the first input of the counter 31, the second input of which is the signal input from the first output of the beacon activation signal input unit 1, and the outputs of the counter 31 are the outputs of the time code generator 12.

Block 13 of the frequency dividers is made in the form of series-connected frequency dividers with division factors 5, 31, 82 and 256. The parallel-to-serial converter 14 is made in the form of a shift register. Shaper 8 control voltage is made in the form of a voltage amplifier.

Emergency beacon operates as follows.

As a result of the action on the sensors of the automatic inclusion of block 22 or the button 23 for manually turning on the block 1 for inputting the emergency beacon activation signal, block 1 generates a potential beacon activation signal. This signal is triggered by the time code generator 12, which counts the time from the moment the beacon was activated, the read-only memory unit 2, which forms the constant part of the message transmitted by the beacon at a frequency of 406 MHz, and includes a phase manipulator 5 that operates at a frequency of 121 MHz.

The modulating code M ₁ (t) (Fig. 5b) generated by the modulating code generator 32 is fed to the first input of the phase manipulator 5, the second input of which is fed into harmonic oscillation from the output of the master crystal oscillator 4 (Fig. 5a):

, 0≤t≤T₁,

, 0≤t≤T ₁ ,

where U ₁ , ω ₁ , φ ₁ , T ₁ - amplitude, carrier frequency, initial phase and duration of harmonic oscillation.

At the output of the phase manipulator 5, a complex signal with phase shift keying (QPSK) is generated (Fig. 5c):

, 0≤t≤T_1,

, 0≤t≤T _1,

- манипулируемая составляющая фазы, отображающая закон фазовой манипуляции в соответствии с модулирующим кодом M₁(t) (фиг.5б), причем φ_к(t)=const при kτ_э<t<(k+1)τ_э и может изменяться скачком при t=kτ_э, т.е. на границах между элементарными посылками (к=1, 2,..., N₁);Where

is the manipulated component of the phase, which displays the law of phase manipulation in accordance with the modulating code M ₁ (t) (Fig.5b), and φ _к (t) = const for kτ _e <t <(k + 1) τ _e and can change abruptly at t = kτ _e , i.e. on the boundaries between elementary premises (k = 1, 2, ..., N ₁ );

τ _e , N ₁ - the duration and number of chips that make up a signal of duration T ₁ (T ₁ = τ _E N ₁ ,);

which through the power amplifier 6 and the duplexer 10 enters the antenna 11 and is radiated into the air. Moreover, the modulating code M ₁ (t) consists of two parts: constant and variable (emergency).

The permanent part is laid down in the message in advance when installing the beacon on a moving object and contains data on the state of the object, its class and individual number.

The variable part of the message, entered at the moment the beacon is turned on, contains data that you need to know to organize the search and rescue operation: the nature of the accident (fire, collision, damage, fault, aground, flooding, dangerous roll, etc.), the coordinates of the object, obtained as a result of recent observations.

All these data are encoded in the form of an alarm message frame and, after switching on the beacon in automatic mode, are periodically sent for reception onboard an artificial satellite. In this case, the Doppler shift of the carrier frequency of the beacon is simultaneously measured to determine its specified coordinates in the ground complex. Reception and decoding of an emergency message allows you to immediately take measures to organize a search and rescue operation.

For the emergency beacon to operate on the channel at a frequency of 406 MHz, the carrier frequency signal is generated by the controlled oscillator 19 and, after being multiplied by two by the frequency multiplier 20, is fed to the first input of the phase manipulator 34 (Fig. 5g):

, 0≤t≤T₂

, 0≤t≤T ₂

At the second input of the phase manipulator 34, a modulating code M ₂ (t) is supplied (Fig. 5d). The modulating code M ₂ (t) contains information similar to the information contained in the modulating code M ₁ (t).

At the output of the phase manipulator 34, the QPSK signal is generated (Fig. 5e)

, 0≤t≤T_2,

, 0≤t≤T _2,

which through a power amplifier 9 and a duplexer 10 enters the antenna 11 and is radiated into the air. Thus, a periodic alternating operation of the transmitting devices of the beacon is organized.

The frequency stabilization generated by the controlled oscillator 19 is stabilized by a phase-locked loop. For this, the output frequency of the controlled oscillator 19 is divided by a frequency divider 21 with a division coefficient 40 to a value close to the frequency of the master crystal 7. The frequencies of the master crystal 7 and the signal from the output of the frequency divider 21 are compared in the phase detector 16. The frequency mismatch signal through the amplifier 18 direct current controls the frequency of the controlled generator 19. A modulating signal is generated at the output of the control voltage generator 8 from the serial code coming from the output of the forming 14 parallel to serial at a predetermined clock frequency and the period of dispensing. Converter 14 generates a serial code from the parallel code of the constant part of the message coming from the outputs of the constant memory unit 2, which is supplemented by a time code in the adder 3. The latter is generated by the time code generator 12. The frequency of the signals that determine the values of the clock frequency of the message, the period of the beacon radiation, the discreteness of the countdown are formed in block 13 of the frequency dividers.

The beacon activation signal input unit 1 operates as follows. When one or more sensors of the automatic switching on of the unit 22 are triggered, a parallel code appears on its output, which arrives at the corresponding address inputs of the programmable read-only memory unit 24 and selects the information at the address that is recorded in the operational memory element 25 and enters the second output of the signal input unit 1 activating the beacon directly and through the OR element 27 to the first output of block 1. When you press the manual power button 23, information is recorded in the operational memory element 26 and through h element OR 27 is supplied to the first output of block 1.

The driver 15 of the modulating signal operates as follows. The grid of modulating frequencies from the third output of the block 13 of the frequency dividers goes to the inputs of the multiplexer 29, and the signal with a clock frequency from the same output of the block 13 goes to the input of the counter 28, which generates control codes of the multiplexer 29. The signal at the output of the multiplexer 29 is a sequence of modulating frequencies .

Shaper 12 time code works as follows.

The signal after sequential division by 5, 31, 82 and 256 in block 13 of the frequency dividers from its first output is fed to the input of the frequency divider 30 with a division ratio of 2700. From the output of the frequency divider 30, a signal with a period of 0.54 is fed to one of the inputs of the counter 31 , the second input of which receives a signal from the output of the beacon activation signal input unit 1, which is an account resolution signal. At the output of the counter 31 appears the code of the time elapsed since the activation of the beacon.

Thus, the proposed emergency beacon in comparison with the prototype and other technical solutions of a similar purpose provides increased reliability of the transmission of disturbing information and the accuracy of determining the coordinates of objects in distress. This is achieved through the use of complex signals with phase manipulation, which have high energy and structural secrecy, and also allow the use of a new type of selection - structural selection. This means that there is a new opportunity to separate signals operating in the same frequency band and at the same time intervals. In principle, you can abandon the traditional method of dividing the operating frequencies of the used range between operating beacons and selecting them on the receiving side using frequency filters. It can be replaced by a new method based on the simultaneous operation of each emergency beacon in the entire frequency range with signals with a complex structure, with the radio receiving device highlighting the signal of the necessary beacon through its structural selection.

The energy secrecy of complex QPSK signals is due to their high compressibility in time and spectrum with optimal processing, which reduces the instantaneous radiated power. As a result, a complex QPSK signal at the receiving point may be masked by noise and interference. Moreover, the energy of a complex QPSK signal is by no means small; it is simply distributed over the time-frequency domain so that at each point of this region the signal power is less than the power of noise and interference.

The structural secrecy of complex QPSK signals is due to the wide variety of their shapes and significant ranges of parameter changes, which makes it difficult to optimize or at least quasi-optimal processing of complex QPSK signals of an a priori unknown structure in order to increase the sensitivity of the receiver.

Claims (1)

An emergency beacon containing a beacon activation signal input block, a permanent memory block, first and second adders, first and second crystal oscillators, first and second power amplifiers, a control voltage shaper, a duplexer, an antenna, a time code shaper, a frequency divider block, a parallel converter code in serial, modulating signal driver, phase detector, DC amplifier, controllable generator, frequency multiplier by two and frequency divider with coefficient division 40, while the first output of the beacon activation signal input block is connected to the input of the permanent memory block, n outputs of which are connected to the first n inputs of the first adder, to the first input of the time code generator, the second output of the beacon activation signal input block is connected to the second input of the first adder , the outputs of the first and second power amplifiers are connected through the duplexer to the antenna, the output of the second master crystal oscillator is connected to the input of the frequency divider block, the first output of which is connected to the second input time code shaper, n outputs of which are connected to the third n inputs of the first adder, n outputs of which are connected to the first n inputs of the parallel code to serial converter, the second input of which is connected to the second output of the frequency divider block, the third n outputs of which are connected to n inputs of the shaper modulating signal, the output of the parallel-to-serial code converter through the control voltage generator is connected to the first input of the second adder, the second input of which is connected with the output of the phase detector, a DC amplifier, a controlled generator and a frequency multiplier by two are connected in series to the output of the second adder, the output of the controlled generator through a frequency divider with a division ratio of 40 is connected to the first input of the phase detector, the second input of which is connected to the output of the second master crystal characterized in that the first and second modulators of the modulating code, the first and second phase manipulators are introduced into it, moreover, to the output of the modulator The first driver of the modulating code and the first phase manipulator are connected in series, the second input of which is connected to the output of the first master crystal oscillator, the third input is connected to the first output of the beacon activation signal input unit, and the output is connected to the input of the first power amplifier, to the output of the control voltage driver a second modulator code driver and a second phase manipulator are connected, the second input of which is connected to the output of the frequency multiplier by two, and the output is connected it is input to the second power amplifier.

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