RU2425423C1 - System for locating and dispatching mobile ambulance crews - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: system comprises Navstar navigation system satellites. A transponder with a transceiving antenna is installed at the centre of the city. There is a dispatch station with known coordinates, an ambulance and fixed equipment installed on profile medical institutions. The dispatch station has a receiving antenna, a GPS signal receiver, a radio station with a transceiving antenna, an interface unit, a computer with a display and a documentation device. The on-board system of the ambulance has a receiving antenna, a GPS signal receiver, a radio station with a transceiving antenna, an interface unit, a microprocessor, additional information sensors and an on-board display. The fixed equipment installed on profile medical institutions includes a radio station with a transceiving antenna, an interface unit and a microprocessor. Each GPS signal receiver has a high frequency amplifier, a heterodyne, a mixer, an intermediate frequency amplifier, two multipliers, a narrow band-pass filter and a low-pass filter. Each radio station has a microprocessor, an interface unit, a driving generator, a discrete message source, a phase manipulator, an analogue message source, an amplitude modulator, two heterodynes, a first intermediate frequency amplifier, two power amplifiers, an antenna switch, three mixers, two second intermediate frequency amplifiers, an amplitude limiter, a synchronous detector, two multipliers, a band-pass filter, a phase detector, a +90° phase changer, a -90° phase changer, an adder, a narrow band-pass filter, an amplitude detector and a switch. The system facilitates exchange of discrete and analogue messages between dispatchers, ambulance crews and doctors on hospitals and polyclinics by suppressing false signals (noise) received from mirror and combinational channels.

EFFECT: high noise immunity and reliability of messaging.

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Description

The invention relates to the field of medical technology, namely to means and systems for remote monitoring the movement of ambulances, and can be used in urban institutions of practical health care.

Known systems and devices for locating and dispatching land transport (author's certificate. USSR No. 215.536, 477.330, 498.636, 696.508, 769.581, 830.447, 1.123.041; RF patents No. 2.033.352, 2.042.548, 2.061,323, 2.184 .992, 2.278.418; V. Bobrin and others. Long-range navigation systems. "Automobile transport", 1991, No. 12, p.23, Fig. 2 and others).

Of the known systems and devices, the closest to the proposed one is the "System for the location and dispatching of mobile ambulance crews" (RF patent No. 2.278.418, G08G 1/123, 2004), which is selected as a prototype.

The specified system provides an increase in the efficiency of remote control from the control center over the current geographical position and state of the ambulance fleet, as well as an increase in the reliability and reliability of the exchange of discrete and analog messages between dispatchers, drivers and teams of ambulances and doctors of hospitals, hospitals and clinics.

Each radio station includes a receiver, which is built according to a superheterodyne circuit and in which the same value of the second intermediate frequency w _pr2 can be obtained by receiving signals at two frequencies w ₂ and w ₃ , i.e.

w _up2 = w ₂ -w _r2 and w _up2 = w _z -w _r2.

Therefore, if the tuning frequency w ₂ to take over the main receiving channel, along with it will be a mirror receiving channel frequency w _of which differs from the frequency w ₂ 2w _up2 and disposed symmetrically (mirror image) with respect to the frequency w _r2 of the second local oscillator (Figure .3). Conversion on the mirror channel of the reception occurs with the same conversion coefficient K _ol as on the main channel.

In addition to the mirror, there are other additional (combinational) reception channels.

In general terms, any combination receive channel takes place when the following conditions are met:

w _up2 = | ± mw _Ki ± nw _r2 |,

where w _кi is the frequency of the i-th Raman reception channel;

m, n, i are positive integers.

The most harmful Raman reception channels are those generated by the interaction of the carrier frequency of the received signal with harmonics of the frequency w _{g2 of the} second small local oscillator (second, third, etc.), since the sensitivity of the receiver through these channels is close to the sensitivity of the main channel.

So, two combinational channels with m = 1 and n = 1 correspond to the frequency (figure 3):

w _k1 = 2w _r2 w -w _up2 and _{k2 r2} = 2w + w _up2.

The presence of false signals (interference) received via mirror and Raman channels leads to a decrease in noise immunity and reliability of the exchange of discrete and analog messages between dispatchers, ambulance teams and doctors of hospitals, hospitals and clinics.

An object of the invention is to increase the noise immunity and reliability of the exchange of discrete and analog messages between dispatchers, teams of ambulances and doctors of hospitals, hospitals and clinics by suppressing false signals (interference) received via mirror and Raman channels.

The problem is solved in that the positioning and dispatching system of mobile ambulance crews, containing, in accordance with the closest analogue, Navstar navigation system satellites, an on-board complex installed on the ambulance car and containing a receiving antenna in series with a GPS signal receiver, a pairing unit, the first input-output of which is connected via a radio station to a transceiver antenna, and the second input-output - to a microprocessor designed to perform navigation calculations, which is connected to a display, a repeater with a transceiver antenna installed in the central part of the city, stationary equipment installed at a control room with known coordinates obtained as a result of precision geodetic surveying, and consisting of a receiving antenna, a GPS signal receiver, a pairing unit, connected in series, the first the input-output of which through a radio station is connected to a transceiver antenna, and the second input-output is connected via a personal computer to a display and a documentation device and, and a radio station installed in a specialized medical institution, the first input-output of which is connected to the transceiver antenna, and the second input-output is connected via the interface unit to the input-output of the microprocessor, while each GPS signal receiver consists of series-connected to the receiving antenna a high-frequency amplifier, a mixer, the second input of which is connected to the output of the local oscillator, an intermediate-frequency amplifier, the first multiplier, the second input of which is connected to the output of the low-pass filter, narrow-band ph tra, the second multiplier, a second input coupled to an output of intermediate frequency amplifier and a low pass filter whose output is the output of the receiver, each radio station utilizes complex signals with the combined phase shift keying and amplitude-modulated are emitted at a single frequency w _1, and taken on another frequency w ₂ , and consists of a serially connected master oscillator, the control input of which is connected through a pairing unit to a microprocessor designed to synchronize operation sources of analog and discrete messages, a phase manipulator, the second input of which is connected to the output of the source of discrete messages, an amplitude modulator, the second input of which is connected to the output of the source of analog messages, the first mixer, the second input of which is connected to the output of the first local oscillator, the amplifier of the first intermediate frequency, the first a power amplifier, an antenna switch, the input-output of which is connected to a transceiver antenna, a second power amplifier, a second mixer, the second input of which connected to the output of the second local oscillator, and the first amplifier of the second intermediate frequency, from the series-connected amplitude limiter and synchronous detector, the output of which is connected to a microprocessor designed to synchronize the operation of sources of analog and discrete messages, the first multiplier is connected in series to the output of the amplitude limiter, the second input of which connected to the output of the second local oscillator, a bandpass filter and a phase detector, the second input of which is connected to the output of the first goethe one, and the output is connected to the microprocessor, the control inputs of discrete and analog messages through the interface unit are connected to the microprocessor, differs from the closest analogue in that each radio station is equipped with a + 90 ° phase shifter, -90 ° phase shifter, a third mixer, a second amplifier and a second intermediate frequency, adder, second multiplier, narrow-band filter, amplitude detector and key, and the phase shifter + 90 °, the third mixer, WTO are connected in series to the output of the second local oscillator a swarm input of which is connected to the output of the second power amplifier, a second amplifier of the second intermediate frequency, a phase shifter of -90 °, an adder, a second input of which is connected to the output of the first amplifier of the second intermediate frequency, a second multiplier, the second input of which is connected to the output of the second power amplifier, narrowband a filter, an amplitude detector and a key, the second input of which is connected to the output of the adder, and the output is connected to the input of the amplitude limiter and to the second input of the synchronous detector.

The general compositional diagram of the system is shown in FIG. The structural diagram of the receiver of GPS signals is shown in figure 2. A frequency diagram explaining the operation of the radio station is shown in FIG. 3. The structural diagram of the radio depicted in figure 4.

The system for locating and dispatching mobile ambulance crews contains satellites 1.L (L = 1, 2 ... 24) of the Navstar navigation system, a repeater 3 with a transceiver antenna 2, installed in the central part of the city, a control station 4 with known coordinates obtained in the result of precision geodetic surveying, consisting of a series-connected receiving antenna 7, a GPS signal receiver 9, a pairing unit 11, the first input-output of which is connected to the transceiver antenna 8 through the radio station 10 and the second input-output d is connected via a personal computer 12 with a display 13 and a documentation device 14, an ambulance 5.i (i = 1, 2 ... n), the on-board complex of which contains a receiving antenna 15.i in series, a GPS signal receiver 17.i, a pairing unit 19.i, the first input-output of which is connected via the radio 18.i to the transceiver antenna 16.i, the second input-output to the microprocessor 20.i, to which the on-board display 22.i is connected, as well as the sensors 21.i additional information connected to the interface unit 19.i, and stationary equipment 6.j (j = 1, 2 ... m), installed at specialized medical institutions (hospitals, hospitals, clinics, etc.) and consisting of a radio station 24.j, the first input-output of which is connected to the transceiver antenna 23.j, and the second input-output is connected through the block 25.j interfaces with microprocessor I / O 26.j.

Each GPS signal receiver consists of a high-frequency amplifier 27, a mixer 29, the second input of which is connected to the output of the local oscillator 28, the intermediate-frequency amplifier 30, the first multiplier 31, the second input of which is connected to the output of the low-pass filter 34, which is connected in series to the receiving antenna a filter 33, a second multiplier 32, the second input of which is connected to the output of the intermediate frequency amplifier 30, and a low-pass filter 34, the output of which is the output of the receiver.

Each radio station consists of a serially connected master oscillator 37, the control input of which is connected through the interface unit 36 to the microprocessor 35, a phase manipulator 39, the second input of which is connected to the output of the source 38 of discrete messages, an amplitude modulator 41, the second input of which is connected to the output of the analog source 40 messages, the first mixer 43, the second input of which is connected to the output of the first local oscillator 42, the amplifier 44 of the first intermediate frequency, the first power amplifier 45, the antenna switch fir-tree 46, the input-output of which is connected to the transceiver antenna, the second power amplifier 47, the second mixer 49, the second input of which is connected to the output of the second local oscillator 48, the amplifier 50 of the second intermediate frequency, adder 60, the second multiplier 61, the second input of which is connected to the output a second power amplifier 47, a narrow-band filter 62, an amplitude detector 63, a key 64, the second input of which is connected to the output of the adder 60, an amplitude limiter 51 and a synchronous detector 52, the second input of which is connected to the output of the key 64, the output is connected to the microprocessor 35, the first multiplier 53 is connected in series to the output of the amplitude limiter 51, the second input of which is connected to the output of the second local oscillator 48, the bandpass filter 54 and the phase detector 55, the second input of which is connected to the output of the first local oscillator 42, and the output is connected to the microprocessor 35, a phase shifter 56 + 90 ° is connected to the output of the second local oscillator 48, the third mixer 57, the second input of which is connected to the output of the second power amplifier 47, the second amplifier 58 of the second intermediate simplicity and phase shifter 59 to -90 °, whose output is connected to the second input of the adder 60.

The system operates as follows.

The operation of the system is based on the use of signals emitted by satellites 1.L (L = 1, 2, ... 24) of the Navstar navigation system.

The Global Positioning System (GPS), also known as the Navstar (Navigation System with Time and Ranging) is designed to transmit navigation signals that can be received simultaneously in all regions of the world.

Each GPS satellite emits at two frequencies (1.575 MHz and 12.275 MHz) a special navigation signal in the form of a binary phase-manipulated (PSK) signal, phase-manipulated by a pseudo-random sequence. Two kinds of code are encrypted in the navigation signal. One of them - the C / A code is available to a wide range of civilian consumers, including the proposed system. It allows you to get only a rough estimate of the location of ambulances, so it is called a "Coarse" code. The C / A code is transmitted at a frequency w _c = 1.575 MHz using phase manipulation with a pseudo-random sequence of 1023 characters in length (elementary premises). Error protection is provided using the Gould code. The repetition period of the C / A code is 1 ms. The clock frequency is 1.023 MHz.

Another code - P provides a more accurate calculation of coordinates, but not everyone is able to use it, access to it is limited by the GPS service provider, it is used by the US military.

The Navstar system includes a space segment consisting of 24 spacecraft, a network of ground-based monitoring stations for their operation, and a user segment (navigation receivers of GPS signals). All satellites 1.L (L = 1, 2 ... 24) are autonomous. The parameters of their orbits are periodically monitored by a network of ground-based tracking stations, with the help of which ballistic characteristics are calculated at least 1-2 times a day, spacecraft deviations from the calculated motion paths are recorded, and the own time of the onboard clock is determined.

To determine the location of the controlled ambulance, the receiver 17.i (i = 1, 2, ... n) receives the PSK signal

u _c (t) = U _c · Cos [w _c t + φ _к (t) + φ _c ], 0≤t≤T _c ,

where U _c , w _c , φ _c , T _c - amplitude, carrier frequency, initial phase and duration of the high-frequency signal;

φ _к (t) = {0, π} is the manipulated component of the phase that displays the law of phase manipulation in accordance with the modulating code M (t), and φ _к (t) = const for Кτ _э <t <(к + 1) τ _e and can change abruptly at t = Kτ _e , i.e. at the borders between elementary premises (K = 1, 2, ..., N-1);

τ _e , N is the duration and number of chips that make up a signal of duration T _s (T _s = N · τ _e , N = 1023).

This signal from the output of the receiving antenna through the high-frequency amplifier 27 is fed to the first input of the mixer 29, to the second input of which the voltage of the local oscillator 28

u _g (t) = U _g Cos (w _g t + φ _g ),

where U _g , w _g , φ _g - amplitude, frequency and initial phase of the local oscillator voltage.

At the output of the mixer 29, voltages of combination frequencies are generated. The amplifier 30 is allocated the voltage of the intermediate (differential) frequency

u _up (t) = U _pr · Cos [w _pr t + φ _k (t) + φ _pr ], 0≤t≤T _c ,

where U _ave = _^1/2 K ₁ · U · U _{d c;}

K ₁ - gear ratio of the mixer;

w _CR = w _c -w _g - intermediate frequency;

φ _CR = φ _s -φ _g ,

which simultaneously enters the inputs of the multipliers 31 and 32. The reference voltage is supplied to the second input of the multiplier 32 from the output of the narrow-band filter 33

u ₀ (t) = U ₀ · Cos [w _{pr pr} t + φ] 0≤t≤T _c.

As a result of the multiplication of these stresses, the resulting voltage is formed.

u _Σ (t) = U _Σ · Cosφ _to (t) + U _Σ · Cos · [2w _pr t + φ _to (t) + 2φ _pr ],

where U _Σ = _^1/2 K ₂ · U · U _{0 ave;}

K ₂ - gear ratio of the mixer.

An analog of the modulating code M (t)

u _n (t) = U _n Cosφ _k (t),

is allocated by the low-pass filter 34 and fed to the output of the receiver and to the second input of the multiplier 31. A harmonic oscillation is generated at the output of the latter

u ₀ (t) = U _p · Cos · [w _pr t + φ _pr ] + U _p · Cos · [w _pr t + 2φ _to (t) + φ _pr ] = 2U _p · Cos (w _pr t + φ _pr ) = U ₀ Cos (w _pr t + φ _pr ).

This oscillation is allocated by a narrow-band filter 33 and is fed to the second input of the multiplier 32.

Multipliers 31 and 32, a narrow-band filter 33, and a low-pass filter 34 form a demodulator of FMN signals.

In this demodulator, the reference voltage necessary for synchronous detection of the received FMN signal is extracted directly from the received signal itself and there is no “reverse operation” phenomenon inherent in the known device (Pistolkors A.A., Siforova V.I., Kostas V.F. , Travina G.A.), which distinguishes the reference voltage from the received FMN-singal.

The GPS receiver alternately uses two main operating modes - receiving information and navigation.

In navigation mode, the location of the ambulance is updated every second and basic navigation data is provided. In the information reception mode, data of the ephemeris and time corrections necessary for the navigation mode are received, and more rare (after one minute) navigation measurements are made.

The microprocessor 20.i (i = 1, 2, ... n), which is part of the on-board complex, ambulance 5.i, has two functions: it serves the receiver 17.i and makes navigation calculations. The first is to select a working constellation of satellites 1.L (L = 1, 2, ... 24), calculate target designation data, store code phase and carrier phase estimates, synchronize by bits, frames, and control the operation of the receiver, for example, switch from the information reception mode to the navigation mode and back. The second function of the microprocessor 20.i consists in calculating the ephemeris, determining the coordinates of the location of the ambulance 5.i and issuing location coordinates for display 22.i.

The 17.i receiver operates in navigation mode until the satellites geometry remains satisfactory or until the ephemeris is out of date. To determine the two coordinates of the place (latitude and longitude) and time, measurements from three satellites are required. In this receiver, information from the fourth "extra" satellite may be necessary during various maneuvers of the ambulance, when it is possible to obscure the signals of one or more satellites.

A standard GPS signal receiver provides a satellite detection time of no more than 3-4 minutes and an error in determining the coordinates of an ambulance no more than 100 m.

To improve the accuracy of determining the location of an ambulance, the differential correction method is used, which is based on the use of the principle of differential navigation measurements, known in radio navigation.

The differential mode allows you to determine the coordinates of the observed ambulance with an accuracy of 5 m in a dynamic navigation environment and up to 2 m in stationary conditions.

The differential mode is implemented using the control receiver 9 GPS signals installed at the control room 4 with known coordinates obtained as a result of precision geodetic surveying. Comparing the known coordinates with the measured ones, the GPS receiver 9 and the computer 12 generate corrections that are transmitted to the ambulance over the air in a predetermined format. The amendments received from the control room 4 are automatically entered in the results of the measurements of the ambulance 5.i (i = 1, 2, ... n).

Discrete and analog messages are exchanged between the control room 4, ambulance 5.i (i = 1, 2, ... n) and the specialized medical institution 6.j (j = 1, 2 ... m) via radio channels directly and / or through repeater 3 installed in the central part of the city. For this purpose, radio stations operating in duplex mode are intended.

Using the microprocessor 35, the master oscillator 37 is turned on, which generates a high-frequency voltage

u ₁ (t) = U ₁ · Cos [w ₁ t + φ ₁ ], 0≤t≤T ₁ ,

which is fed to the first input of the phase manipulator 39, to the second input of which a modulating code M ₁ (t) is supplied from the output of the source 38 of discrete messages. The output of the phase manipulator 39 generates a phase-shift (PSK) signal

u ₂ (t) = U ₂ · Cos [w ₁ t + φ _к1 (t) + φ ₁ ], 0≤t≤T ₁ ,

which is supplied to the first input of the amplitude modulator 41, to the second input of which a modulating function is supplied, m ₁ (t) from the output of the source of analog messages. At the output of the amplitude modulator 41, a complex signal is generated with combined phase shift keying and amplitude modulation (FMN-AM)

u ₃ (t) = U ₃ [1 + m ₁ (t)] · Cos [w ₁ t + φ _к1 (t) + φ ₁ ], 0≤t≤T ₁ ,

where m ₁ (t) is the modulating function that displays the law of amplitude modulation.

The operation of discrete 38 and analog 40 message sources is synchronized by the microprocessor 35 through the pairing unit 36.

The generated signal u ₃ (t) is fed to the first input of the mixer 43, the second input of which is supplied with the voltage of the first local oscillator 42

u _g1 (t) = U _g1 · Cos [w _g1 t + φ _g1 ].

At the output of the mixer 43, voltages of combination frequencies are generated. The amplifier 44 is allocated the voltage of the first intermediate (total) frequency

u _pr1 (t) = U _pr1 [1 + m ₁ (t)] · Cos [w _pr1 t + φ _к1 (t) + φ _pr1 ], 0≤t≤T ₁ ,

where U _pr1 = _^1/2 K ₁ · U ₁ · U _d1;

w _pr1 = w ₁ + w _g1 - the first intermediate frequency;

φ _pr1 = φ ₁ + φ _g1 ,

which is amplified in the power amplifier 45 and is transmitted through the antenna switch 46 and the transceiver antenna.

Voltage, which is a complex FMN-AM signal emitted by another radio station

u ₄ (t) = U ₂ [1 + m ₂ (t)] · Cos [w _g1 t + φ _к2 (t) + φ ₂ ], 0≤t≤T ₂ ,

where w _g1 = w ₂ ;

is received by the antenna and through the antenna switch 46 and the second power amplifier 47 is supplied to the first inputs of the second 49 and third 57 mixers and the second multiplier 61. The second inputs of the mixer 48 are supplied to the second inputs of the mixers 49 and 57:

u _g2 (t) = U _g2 Cos (w _g2 t + φ _g2 ),

u _g3 (t) = U _g2 · Cos (w _g2 t + φ _g2 + 90 °).

Moreover, the frequencies w _g1 and w _{g2 of the} first 24 and second 48 local oscillators are spaced by the value of the second intermediate frequency w _g2 -w _g1 = w _up2 .

At the output of the mixers 49 and 57, voltages of combination frequencies are generated. Amplifiers 50 and 58 are allocated voltage of the second intermediate (differential) frequency:

u _up2 (t) = U _pr2 [1 + m ₂ (t)] · Cos [w _up2 t-φ _к2 (t) + φ _up2 ],

u _up3 (t) = U _pr2 [1 + m ₂ (t)] · Cos [w _up2 t-φ _к2 (t) + φ _up2 + 90 °], 0≤t≤T ₂ ,

Where are _np2 U = _^1/2 K ₁ · U ₂ · U _r2;

w _up2 = wг2-w2 - second intermediate (difference) frequency;

φ _up2 = φ ₂ -φ _r2.

The voltage u _up3 (t) from the output of the second amplifier 58 of the second intermediate frequency is supplied to the input of the phase shifter 59 by -90 °, at the output of which a voltage is generated

u _up4 (t) = U _pr2 [1 + m ₂ (t)] · Cos [w _up2 t-φ _к2 (t) + φ _up2 + 90 ° -90 °] = U _pr2 [1 + m ₂ (t) ] Cos [w _up2 t-φ _к2 (t) + φ _up2 ]

Voltages u _up2 (t) and u _up4 (t) are supplied to two inputs of the adder 60, at the output of which the first total voltage is formed

u _Σ1 (t) = U _Σ1 [1 + m ₂ (t)] · Cos [w _up2 t-φ _к2 (t) + φ _up2 ],

where U _Σ1 = 2U _up2 ;

which goes to the second input of the second multiplier 61. At the output of the latter, a harmonic voltage is generated

u ₅ (t) = U ₅ [1 + m ₂ (t)] ² · Cos [w t + φ _{r2 r2],} 0≤t≤T ₁

wherein U ₅ = ¹ / K _{2 2} · U ₂ · U _Σ1;

K ₂ - transfer coefficient of the multiplier;

which is allocated by the narrow-band filter 62, is detected by the amplitude detector 63 and is supplied to the control input of the key 64, opening it. In the initial state, the key 64 is always closed.

The tuning frequency w _{n of the} narrow _- band filter 62 is chosen equal to the frequency of the second local oscillator 48

w _n = w _r2 .

The voltage u _Σ1 (t) from the output of the adder 60 through the public key 64 is supplied to the first (information) input of the synchronous detector 52 and to the input of the amplitude limiter 51, at the output of which a voltage is generated

u ₆ (t) = U _ogre · Cos [w _pr2 t-φ _к2 (t) + φ _up2 ],

where U _ogre is the limit threshold,

which is a PSK signal and is supplied to the second (reference) input of the synchronous detector 52 as a reference voltage. The output of the synchronous detector 52 produces a low-frequency voltage

u _н1 (t) = U _н1 [1 + m ₂ (t)],

where U _H1 = _^1/2 · K ₃ · U U _{Σ1 ogre;}

K ₃ - transfer coefficient of the synchronous detector;

proportional to the modulating function m ₂ (t). This voltage is supplied to the microprocessor 35.

The voltage u ₆ (t) from the output of the amplitude limiter 51 is simultaneously supplied to the first input of the multiplier 53, the second input of which is supplied with the voltage u _g2 (t) from the output of the second local oscillator 48. A voltage is generated at the output of the multiplier 53

u ₇ (t) = U ₇ · Cos [w _g1 t + φ _к2 (t) + φ _g1 ], 0≤t≤T ₂ ,

where U ₇ = ¹ / K ₂ · U ₂ · U _{Res r2;}

w = w _{r1 r2} -w _up2;

cp = φ _{r1 r2} -φ _up2,

which is a PSK signal at a frequency w _{g1 of the} first local oscillator 42. This voltage is extracted by a band-pass filter 54 and supplied to the first (information) input of the phase detector 55, to the second (reference) input of which the voltage u _g1 (t) of the first local oscillator 42 is supplied. The output of the phase detector 55 produces a low-frequency voltage

u _n2 (t) = U _{n2 Cosφ k2} (t),

where U _H2 = _^1/2 K ₄ · U · U _{r1 7;}

K ₄ - the transfer coefficient of the phase detector,

proportional to the modulating code M ₂ (t). This voltage is supplied to the microprocessor 35.

The system operation described above corresponds to the reception of useful QPSK signals along the main channel at a frequency w ₂ (Fig. 3).

If a false signal (interference)

u ₃ (t) = U ₃ · Cos (w ₃ t + φ ₃ ), 0≤t≤T ₃ ,

taken through the mirror channel at a frequency of w ₃ , the following voltages are allocated by amplifiers 50 and 58 of the second intermediate frequency:

u _up5 (t) = U _pr5 Cos (w _up2 t + φ _up5 ),

u _up6 (t) = U _pr5 · Cos (w _up2 t + φ _up5 -90 °), 0≤t≤T ₃ ,

where U _np5 = _^1/2 K ₁ · U · U _{r2 3;}

w _up2 = w ₃ -w _g2 - the second intermediate (difference) frequency;

φ _up5 = φ ₃ -φ _g2 .

The voltage u _up6 (t) from the output of the second amplifier 58 of the second intermediate frequency is supplied to the input of the phase shifter 59 by -90 °, at the output of which a voltage is generated

u _up7 (t) = U _pr5 · Cos (w _up2 t + φ _up5 -90 ° -90 ° ) = - U _pr5 · Cos (w _up2 t + φ _up5 ).

The _voltages u _up5 (t) and u _up7 (t) supplied to the two inputs of the adder 60 are compensated at its output.

Therefore, a false signal (interference) received on the mirror channel at a frequency w ₃ is suppressed.

For a similar reason, a false signal (interference) received on the second combination channel at a frequency w _{k2 is also} suppressed.

If a false signal (interference) is received on the first combinational channel at a frequency w _k1

u _k1 (t) = U _k1 · Cos (w _k1 t + φ _k1 ), 0≤t≤T _k1 ,

the amplifiers 50 and 58 of the second intermediate frequency are allocated the following voltages:

u _up8 (t) = U _pp8 Cos (w _up2 t + φ _up8 ),

u _up9 (t) = U _pp8 Cos (w _up2 t + φ _up8 +90 ° ), 0≤t≤T _k1 ,

Where are U _pp8 = _^1/2 K _{1 k1} · U · U _r2;

w _up2 = 2w _r2 -w _k1 - second intermediate (difference) frequency;

φ _up8 = φ -φ _{r2 k1.}

The voltage u _up9 (t) from the output of the second amplifier 58 of the second intermediate frequency is supplied to the input of the phase shifter 59 by -90 °, at the output of which a voltage is generated

u _up10 (t) = U _pr8 · Cos (w _up2 t + φ _up8 +90 ° -90 ° ) = U _up8 · Cos (w _up2 t + φ _up8 ), 0≤t≤T _к1

Voltages u _up8 (t) and u _up10 (t) are supplied to two inputs of the adder 60, at the output of which the total voltage is formed

u _Σ2 (t) = U _Σ2 · Cos (w _up2 t + φ _up8 ), 0≤t≤T _к1 ,

where U _Σ2 = 2U _up8 .

This voltage is supplied to the second input of the multiplier 61, at the output of which the following voltage is formed

₈ u (t) = U ₈ · Cos (2w _{r2 r2} t + φ), 0≤t≤T _k1,

where U ₈ = ¹ / K ₂ · U ₂ · U _{k1 Σ2.}

This voltage does not fall into the passband of the narrow-band filter 62.

Therefore, a false signal (interference) received on the first combinational channel at a frequency w _k1 is suppressed.

Thus, the proposed system, in comparison with the prototype and other technical solutions of a similar purpose, provides increased noise immunity and reliability of the exchange of discrete and analog messages between dispatchers, ambulance teams and doctors of hospitals, hospitals and clinics. This is achieved by suppressing false signals (interference) received via mirror and Raman channels, phase-compensation method and narrow-band filtering method.

Claims (1)

A system for locating and dispatching mobile ambulance crews containing Navstar navigation system satellites, an on-board complex installed on an ambulance car and containing a receiving antenna in series, a GPS signal receiver, a pairing unit, the first input-output of which is connected to the transceiver via a radio station antenna, and the second input-output is connected to a microprocessor designed to perform navigation calculations, to which an on-board display, a transceiver with transceiver is connected antenna installed in the central part of the city, stationary equipment installed at the control room with known coordinates obtained as a result of precision geodetic surveying, and consisting of a series-connected receiving antenna, GPS-signal receiver, interface unit, the first input-output of which is via a radio station connected to a transceiver antenna, and the second input-output connected via a personal computer with a display and documentation device, and a radio station mounted on a specialized medical m institution, the first input-output of which is connected to the transceiver antenna, and the second input-output is connected via a pairing unit to the input-output of the microprocessor, while each GPS signal receiver consists of a high-frequency amplifier, mixer, and a second input connected in series to the receiving antenna which is connected to the output of the local oscillator, the intermediate frequency amplifier, the first multiplier, the second input of which is connected to the output of the low-pass filter, narrow-band filter, the second multiplier, the second input of which is connected With the output of the intermediate frequency amplifier and the low-pass filter, the output of which is the output of the GPS signal receiver, each radio station uses complex signals with combined phase shift keying and amplitude modulation, which are emitted at one frequency w ₁ and received at another frequency w ₂ , and consists of a serially connected master oscillator, the control input of which is connected through a pairing unit to a microprocessor designed to synchronize the operation of sources of analog and discrete messages phase manipulator, the second input of which is connected to the output of the source of discrete messages, an amplitude modulator, the second input of which is connected to the output of the source of analog messages, the first mixer, the second input of which is connected to the output of the first local oscillator, the amplifier of the first intermediate frequency, the first power amplifier, antenna switch the input-output of which is connected to the transceiver antenna, the second power amplifier, the second mixer, the second input of which is connected to the output of the second local oscillator, and the first about the amplifier of the second intermediate frequency, from the series-connected amplitude limiter and the synchronous detector, the output of which is connected to the microprocessor, the first multiplier is connected to the output of the amplitude limiter, the second input of which is connected to the output of the second local oscillator, a bandpass filter and a phase detector, the second input of which is connected the output of the first local oscillator, and the output is connected to the microprocessor, the control inputs of discrete and analog messages through the interface block microprocessor, characterized in that each radio station is equipped with a phase shifter of + 90 °, a phase shifter of -90 °, a third mixer, a second amplifier of a second intermediate frequency, an adder, a second multiplier, a narrow-band filter, an amplitude detector and a key, and to the output of the second local oscillator a phase shifter + 90 °, a third mixer, the second input of which is connected to the output of the second power amplifier, a second amplifier of a second intermediate frequency, a phase shifter of -90 °, an adder, a second input, are connected in series which is connected to the output of the first amplifier of the second intermediate frequency, the second multiplier, the second input of which is connected to the output of the second power amplifier, a narrow-band filter, an amplitude detector and a key, the second input of which is connected to the output of the adder, and the output is connected to the input of the amplitude limiter and to the second input synchronous detector.

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