RU2622511C1 - Method of clock synchronization and device for its implementation - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: device, implementing the proposed method contains the artificial earth satellite and five ground stations, each containing the frequency and time standard 1, heterodynes 2.1 and 2.2, the pseudo-random signal generator 3, the switch 4, the mixers 5, 13, 19, the amplifier 6 of the first intermediate frequency, the power amplifiers 7 and 12, the duplexer 8, the transmit and receive antenna 9, the clippers 10, 15, 33, 39 and 45, the buffer memories 11, 16, 34, 40 and 46, the amplifiers 14, 20 of the second intermediate frequency, the meters 17, 35, 41 and 47 delays and their derivatives, phase shifters 18, 21, 27 for 90º, the adders 22, 28 and 50, the multipliers 23, 29, the narrowband filters 24, 30, the amplitude detectors 25, 31, the switches 26, 32, 38, 44, the signal processing units 48.1, 48.2 and 48.3, units 49.1, 49.2 and 49.3 of time series formation of the total electronic content, the threshold unit 51, the computer 52.

EFFECT: extension of the functional capabilities of the known technical solutions by determining the propagation velocity and the direction of the ionospheric disturbance arrival, caused by various destabilizing factors, due to the restoration of the ionosphere total electron content spatial distribution according to the atmosphere continuous electromagnetic transmission probing data by the repeated signals.

2 cl, 5 dwg

Description

The proposed method and device relates to communication and radar technology and can be used in radio interferometry with extra-long bases (VLBI), as well as in the service of a single time and frequency.

Known methods and devices for clock synchronization (ed. Certificate of the USSR No. 591.799, 614.416, 970.300, 1.180.835, 1.244.632, 1.278.800; RF patents No. 2.003.157, 2.040.035, 2.177.167, 2.182. 341, 2.248.669, 2.292.574, 2.301.437, 2.439.643, 2.535.653; US patent No. 5.519.759; German patent No. 3.278.943; patent EP No. 0.564.220; patent WO No. 99/97.826 and others.

Of the known methods and devices closest to the proposed are the "Method of clock synchronization and device for its implementation" (RF patent No. 2.439.643, G04C 11/02, 2014), which are selected as the base objects.

The aforementioned method and device provide a comparison of time scales spaced over long distances, and are based on the use of the duplex method of communication through a geostationary satellite repeater.

However, the potential capabilities of the known technical solutions are not fully utilized.

Using radio illumination of the atmosphere (the troposphere and parts of the ionosphere) with the help of four frequencies, we can estimate the propagation velocity and direction of arrival of the ionospheric disturbance. The ionospheric disturbance can be caused by solar, geomagnetic and seismic activity, a harbinger of an earthquake, volcanic eruptions, tsunamis, thunderstorm processes, the dynamics of powerful storm cyclones, nuclear and other large explosions and fires, large accidental releases from nuclear power plants, spacecraft and rocket launches, radiations of powerful radio transmitting complexes of radar and connected purpose.

The ionosphere is an ionized atmospheric layer in the altitude range of 5-500 km, which contains free electrons. The presence of these electrons causes a delay in the propagation of the relay signal, which is directly proportional to the electron concentration and inversely proportional to the square of the frequency of the relay signal.

To calculate the ionospheric correction, the measurement of pseudorange at two frequencies is used:

,Where

,

f ₁ , f ₂ - frequencies of relayed signals (f ₁ = f _c , f ₂ = f ₃ , f _k1 , f _k2 );

D ₁ , D ₂ - measured pseudorange at frequencies fi and f _2, respectively.

The ionospheric correction of the pseudorange eliminates a systematic error of the order of 5 meters in determining the position vector of the observer at rest.

The troposphere is the lowest layer of the atmosphere (up to an altitude of 8-13 km). It also causes a delay in the propagation of the signal from the satellite repeater. Signal delay in the troposphere is also caused by refraction effects. Unlike the ionospheric delay, the tropospheric delay does not depend on the signal frequency, it depends on meteorological parameters (pressure, temperature, humidity), and also on the height of the satellite repeater above the horizon. To calculate the tropospheric correction, measurements of pseudorange use measurements of temperature, air pressure, and partial pressure of water vapor. These measurements are available on the Internet for each point A, B, C, D and E, FIG. one.

The ratio for calculating the tropospheric correction of the pseudorange of the ground observer has the form:

where T is the temperature in K;

P is the air pressure [mb];

In - partial pressure of water vapor [mb];

Θ - zenith angle of direction to the satellite repeater.

Tropospheric delays cause measurement errors of 1 meter pseudorange. The determination of the total electronic content (TEC) of the ionosphere is carried out by two-frequency range measurements between the satellite repeater by the ground receiver

where f _1, f ₂ , λ ₁ , λ ₂ - frequency and wavelength of the relayed signals;

L ₁ λ ₁ . L ₂ λ ₂ is the phase path of transionospheric signals (L ₁ , L ₂ is the number of full rotations of the phase);

Θ - zenith angle of the beam; receiver - satellite repeater.

The set of receiver-AES repeater beams in a given region forms a receiving array, each i-th element of which at time t is characterized by a change in the TEC value Y _i (t) and the position of the corresponding ionospheric point X _i (t), Y _i (t) and Z _i (t).

The time series of TECs reflect both regular changes in TECs at the registration point and variations in TECs caused by ionospheric disturbances of a different nature.

An object of the invention is to expand the functionality of known technical solutions by determining the propagation velocity and direction of arrival of the ionospheric disturbance caused by various destabilizing factors, by restoring the spatial distribution of the total electronic content of the ionosphere according to atmospheric radio transmission signals relayed signals.

The problem is solved in that the method of clock synchronization, based, in accordance with the closest analogue, on the simultaneous reception of spaced ground-based points of noise-like microwave signals from the artificial Earth satellite, coherently converting them to a video frequency, digital recording of received signals and determining the time delay of arrival of one of the same signal to synchronization points by the method of correlation processing of registered signals, the magnitude of which compares time scales, while in the initial time t ₁ according to the clock of the first point using a code sequence form a noise-like microwave signal, register it at the same point, the generated signal is converted to a frequency ω ₁ amplify it in power, emit an amplified signal in the direction of the artificial Earth repeater, at the same time point t _1, the clock of the second item with the same code sequence form the same noise-like microwave signal, it is recorded in the second paragraph, taking onboard equipment artificially of Earth relay signal of the satellite at a frequency ω _1, re-emit it at first and second points at the frequency ω ₂ while preserving phase relationships, at an arbitrary time t ₃ by the clock of the second paragraph similarly formed and recorded noise-like microwave signal generated signal is converted to frequency ω _1, increase its power emit the amplified signal in the direction of the same artificial satellite repeater earth, in the same moment of time t ₃ by the clock of the first item by using the same code sequence that is formed oh same noise-like microwave signal is recorded it at the first location, receiving a noise-like signal in the main channel at frequency ω _2, is converted in frequency using the voltage of the second local oscillator shifted in phase by + 90 °, isolated first and second voltage of the second intermediate frequency, the second voltage of the second intermediate frequency is phase shifted by -90 °, summed with the first voltage of the second intermediate frequency, multiply the obtained first total voltage with the received noise-like signal, emit harmonic the voltage at a frequency ω _{G2 of the} second local oscillator, it is detected and used to resolve further processing of the received signal, differs from the closest analogue in that the received noise-like signal through a mirror channel at a frequency of ω _{З1 is} converted in frequency using the voltage of the second local oscillator and the voltage of the second local oscillator shifted in phase by + 90 °, the third and fourth voltages of the second intermediate frequency are isolated, respectively, the fourth voltage of the second intermediate frequency is shifted by + 90 °, summed with retim voltage of the second intermediate frequency, multiplies the resultant second sum voltage with the received spread spectrum signal, allocate the second harmonic voltage at frequency ω _r2 of the second local oscillator is detected it and is used to permit digital recording of the second sum voltage, determine the time delay of arrival of the same at the frequency of signal ω _З in the first and third synchronization points by the method of correlation processing of registered signals, the magnitude of which is used to compare the scales in belts, receive a noise-like signal through the first combination channel at a frequency ω _K1 , convert the frequency using the voltage of the second local oscillator and the voltage of the second local oscillator, phase shifted by + 90 °, emit the fifth and sixth voltages of the second intermediate frequency, respectively, shift the sixth voltage of the second intermediate frequency by -90 °, summarized with the fifth voltage of the second intermediate frequency, multiplied the obtained third total voltage with the received noise-like signal, emit the third harmonic voltage at a frequency of 2ω _{G2 of the} second local oscillator, detect it and use it to digitally record the third total voltage, determine the time delay of the arrival of the same signal at a frequency of ω _K1 at the first and fourth synchronization points by the method of correlation processing of recorded signals, the magnitude of which is produced comparison of time scales, a noise-like signal is received over the second combination channel at a frequency ω _K2 , converted in frequency using the voltage of the second local oscillator, and the voltage of the second local oscillator phase-shifted by + 90 °, the seventh and eighth voltage of the second intermediate frequency are allocated, respectively, the eighth voltage of the second intermediate frequency is shifted by + 90 °, summed with the seventh voltage of the second intermediate frequency, the resulting fourth total voltage is multiplied with the received noise-like signal , allocate the fourth harmonic voltage at frequency 2ω _T2 of the second local oscillator is detected and it is used to permit registration of the fourth digital sum voltage I, determine the time delay of the arrival of the same signal at a frequency ω _K2 at the first and fifth synchronization points by the method of correlation processing of recorded signals, the magnitude of which compares time scales, differs from the closest analogue in that they analyze data on the total electronic content in the ionosphere Earth, which is obtained as a result of processing signals received by dual-frequency receivers of ground points, followed by the formation of time series of the full electronic content and their ph by leaching in the range of oscillation periods corresponding to the response of the ionosphere to the action of the ionospheric disturbance source, an extended receiving antenna system is used and the hypothesis about the values of the arrival direction and propagation velocity of the plane front of the ionospheric disturbance is tested by forming the radiation pattern of the receiving system and scanning it in a given sector, space survey direction of arrival - ionospheric disturbance propagation velocity due to synthesis output signal of the receiving system during in-phase summation of the series of variations in the total electronic content of individual antennas of the system with time shifts calculated based on the verified values of the direction of the ionospheric disturbance and the distances traveled by the front of the ionospheric disturbance between the antenna of the system in the checked direction inside the spherical layer of the Earth’s ionosphere, the decision on the correctness of the checked hypotheses and the detection of ionospheric disturbances is accepted when the total signal exceeds a predetermined threshold match, the corresponding values of direction of arrival and phase velocity of ionospheric disturbance estimated values are considered.

The problem is solved in that the clock synchronization device, containing, in accordance with the closest analogue, a geostationary satellite repeater, first and second ground stations, each of which contains a frequency and time standard, a first local oscillator, a first mixer, and a second input through the switch is connected to the first output of the pseudo-noise signal generator, an amplifier of the first intermediate frequency, a first power amplifier, a duplexer, the input-output of which is connected to the transceiver antenna , a second power amplifier, a second mixer, the second input of which is connected through the second local oscillator to the first output of the frequency and time standard, the first amplifier of the second intermediate frequency, the first adder, the first multiplier, the second input of which is connected to the output of the second power amplifier, the first narrow-band filter, the first an amplitude detector, the first key, the second input of which is connected to the output of the first adder, the second clipper, the second input of which is connected to the third output of the frequency and time standard, the second buffer a flicker device and a first delay meter and their derivatives, the output of which is the first output of a ground station, connected in series to the second output of the pseudo-random signal generator, a first clipper, the second input of which is connected to the second output of the frequency and time standard, and a first buffer storage device, the output of which connected to the second input of the first delay meter and their derivatives, serially connected to the output of the second local oscillator, the first phase shifter + 90 °, the third mixer, the second the first input of which is connected to the output of the second power amplifier, the second amplifier of the second intermediate frequency and the second phase shifter -90 °, the output of which is connected to the second input of the first adder, sequentially connected to the output of the second amplifier of the second intermediate frequency third phase shifter + 90 °, the second adder the second input of 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, the second narrow-band filter, a swarm amplitude detector, a second key, the second input of which is connected to the output of the second adder, a third clipper, the second input of which is connected to the third output of the frequency and time standard, a third buffer memory and a third delay meter and their derivatives, the second input of which is connected to the output of the first buffer storage device, and the output is the second output of a ground station, the third narrow-band filter, the third amplitude detector, the third key are connected in series to the output of the first multiplier the second input of which is connected to the output of the first adder, the fourth clipper, the second input of which is connected to the third output of the frequency and time standard, the fourth buffer memory and the third delay meter and their derivatives, the second input of which is connected to the output of the first buffer memory, and the output is the third output of a ground station, the fourth narrow-band filter, the fourth amplitude detector, the fourth key, the second input of which are connected to the output of the second multiplier connected to the output of the second adder, the fifth clipper, the second input of which is connected to the third output of the frequency and time standard, the fifth buffer memory and the fourth delay meter and their derivatives, the second input of which is connected to the output of the first buffer memory, and the output is the fourth output of the ground paragraph, differs from the closest analogue in that it is equipped with three signal processing units, three units for generating time series of full electronic content, the third adder ohm, a threshold unit and a computer, and the first signal processing unit, the second input of which is connected to the output of the fourth key, the first unit for generating time series of full electronic content, the third adder, the threshold unit and the switch, the second input of which is connected to the antenna control unit, the second signal processing unit, the second input of which is connected to the output of the second key, and the second block for generating time series are sequentially connected to the output of the first key of the complete electronic content, the output of which is connected to the second input of the third adder to the output of the first key, a third signal processing unit is connected in series, the second input of which is connected to the output of the third key, and the third block of time series formation of the complete electronic content, the output of which is connected to the third input of the third adder.

The geometric arrangement of ground posts A, B, C, D, E and the satellite repeater S is shown in FIG. 1, where the following notation is introduced: O is the center of mass of the Earth; d ₁ , d ₂ , d ₃ , d ₄ are the bases of the interferometer, r is the radius vector of the satellite repeater. The timing diagram of the duplex method of comparing the clocks of the first A and second B points is shown in FIG. 2, where the following notation is introduced: S, A, B are the time scales of the satellite repeater and points A and B, respectively. The structural diagram of the equipment of one of items (A) that implements the proposed method for clock synchronization is shown in FIG. 3. A frequency diagram illustrating frequency conversion of signals is shown in FIG. 4. The geometry of determining the coordinates of a remote point source of ionospheric disturbance is shown in FIG. 5.

The equipment of ground station A contains serially connected frequency and time standard 1, a first local oscillator 2.1, a first mixer 5, a second input of which is connected via a switch 4 to the first output of a pseudo-random signal generator 3, an amplifier 6 of a first intermediate frequency, a first power amplifier 7, a duplexer 8, the input-output of which is connected to the transceiver antenna 9, the second power amplifier 12, the second mixer 13, the second input of which is connected to the first output of the frequency and time standard through the second local oscillator 2.2, the first amplifier a second intermediate frequency amplifier 14, a first adder 22, a first multiplier 23, the second input of which is connected to the output of the second power amplifier 12, the first narrow-band filter 24, the first amplitude detector 25, the first key 26, the second input of which is connected to the output of the first adder 22, the second clipper 15, the second input of which is connected to the third output of the frequency and time standard 1, the second buffer memory 16 and the first delay meter 17 and their derivatives, the output of which is the first output 1 of the ground point, to the second the output of the pseudo-random signal generator 3 is connected in series to the first clipper 10, the second input of which is connected to the second input of the frequency and time standard, and the first buffer storage device 11, the output of which is connected to the second input of the first delay meter 17 and their derivatives. The output of the second local oscillator 22 is connected in series to the first phase shifter 18 by + 90 °, the third mixer 19, the second input of which is connected to the output of the second power amplifier 12, the second amplifier 20 of the second intermediate frequency and the second phase shifter 21 by -90 °, the output of which is connected to the second the input of the first adder 22. To the output of the second amplifier 20 of the second intermediate frequency, the third phase shifter 27 is connected + 90 °, the second adder 28, the second input of which is connected to the output of the first amplifier 14 of the second intermediate frequency , a second multiplier 29, the second input of which is connected to the output of the second power amplifier 12, the second narrow-band filter 30, the second amplitude detector 31, the second key 32, the second input of which is connected to the output of the second adder 28, the third clipper 33, the second input of which is connected to the third the output of frequency and time standard 1, a third buffer memory 34 and a second delay meter 35 and their derivatives, the second input of which is connected to the output of the first buffer memory 11, and the output is the second output II a lot of item. The third narrow-band filter 36, the third amplitude detector 37, the third key 38, the second input of which is connected to the output of the first adder 22, the fourth clipper 30, the second input of which is connected to the third output of the frequency and time standard 1, are connected to the output of the first multiplier 23, the fourth buffer a storage device 40 and a third meter 41 of delays and their derivatives, the second input of which is connected to the output of the first buffer storage device 11, and the output is the third W output of a ground station. The fourth narrow-band filter 42, the fourth amplitude detector 43, the fourth key 44, the second input of which is connected to the output of the second adder 28, the fifth clipper 45, the second input of which is connected to the third output of the frequency and time standard 1, are sequentially connected to the output of the second multiplier 29, the fifth buffer a storage device 46 and a fourth meter 47 of delays and their derivatives, the second input of which is connected to the output of the first buffer storage device 11, and the output is the fourth IV output of a ground station.

The first signal processing unit 48.1 is connected in series to the output of the first key 26, the second input of which is connected to the output of the fourth key 44, the second block 49.1 for generating time series of full electronic holding, the third adder 50, the threshold block 51, and the computer 52, the second input of which is connected to the block antenna control 9. To the output of the first key 26, a second signal processing unit 48.2 is connected in series, the second input of which is connected to the output of the second key 32, and the second block 49.2 generating time series of a complete electronically content, the output of which is connected to the second input of the third adder 50. A third signal processing unit 48.3 is connected to the output of the first key 26, the second input of which is connected to the output of the third key 38, and the third block 49.3 of the formation of time series of full electronic content, the output of which is connected with the third input of the third adder 50.

Clock synchronization by the proposed method is as follows.

At time t ₁ ^A, according to the clock of the first point A, a noise-like microwave signal is generated using a code sequence (signal α ₁ ) (Fig. 2):

u _s (t) = U _s cos [ω _s t + ϕ _k (t) + ϕ _c ], 0≤t≤T _c ,

where U _s , ω _s , ϕ _s , T _s - amplitude, carrier frequency, initial phase and signal duration;

ϕk (t) = {0, π} is the manipulated component of the phase that displays the law of phase manipulation in accordance with the code sequence M (t), and ϕ _k (t) = const for kτ _Э <t <(k + 1) τ _Э and can change abruptly at t = kτ _Oe , i.e. at the borders between elementary premises (K = 1, 2, ... N-1);

t _E , N is the duration and number of chips that make up a signal of duration T _s (T _s = Nτ _E ) in generator 3 using frequency and time standard 1.

The specified signal is input to the clipper 10, and then registered in the buffer memory 11. Registration is synchronized by standard 1 frequency and time.

The generated signal u _c (t) is fed to the first input of the first mixer 5, the second input of which is supplied with the voltage of the first local oscillator 2.1

u _Г1 (t) = U _Г1 cos (ω _Г1 t + ϕ _Г1 ).

At the output of the mixer 5, voltages of combination frequencies are generated. Amplifier 6 distinguishes the voltage of the first intermediate (total) frequency

u _CR1 (t) = U _CR1 cos [ϕ _CR1 t + ϕ _k (t) + ϕ _CR1 ], 0≤t≤T _s ,

;Where

;

To ₁ - gear ratio of the mixer;

ω _CR1 = ω _s + ω _G1 - the first intermediate (total) frequency;

ϕ _pr1 = ϕ _with + ϕ _G1 ,

which, after amplification in the power amplifier 7, through the duplexer 8 and the transceiver antenna 9 is radiated in the direction of the satellite repeater at a frequency of ω ₁ = ω _pr1 .

At the same time t ₁ ^A = t ₁ ^B according to the clock of the second point B using the same code sequence M (t) form the same noise-like microwave signal (signal β ₁ ). Register it at the second point (signal β ₁ , which, however, is not sent for relay). Accept on-board equipment of the satellite repeater at a frequency of ω ₁ (signal α ₁ ), re-emit it to points A and B at a frequency of ω ₂ while maintaining phase relationships in the interval t _s .

Relay signal (signal α ₂ ) at a frequency of ω ₂

u ₂ (t) = U ₂ cos [ω ₂ t + ϕ _k (t) + ϕ ₂ ], 0≤t≤T _s ,

is received by the transceiver antenna 9 and through the duplexer 8 and the power amplifier 12 is supplied to the first inputs of the second 13 and third 19 mixers and multiplier 23. The second inputs of the second local oscillator 2.2 are supplied to the second inputs of the mixers 13 and 19:

u _Г2 (t) = U _Г2 (ω _Г2 t + ϕ _Г2 ),

u _Г3 (t) = U _Г2 cos (ω _Г2 t + ϕ _Г2 + 90 °).

Moreover, the frequencies ω _G1 and ω _{G2 of the} first 2.1 and second 2.2 local oscillators are spaced at the second intermediate frequency

w _{G1 G2} -ω = ω _WP2.

At the outputs of the mixers 13 and 19, voltages of combination frequencies are generated. Amplifiers 14 and 20 are allocated voltage of the second intermediate (differential) frequency:

u _CR2 (t) = U _CR2 cos [ω _CR2 (t) -ϕ _K1 (t) + ϕ _CR2 ],

u _CR3 (t) = U _CR2 cos [ω _CR2 (t) -ϕ _K1 (t) + ϕ _CR2 + 90 °], 0≤t≤T _s ,

;Where

;

ω _CR2 = ω _G2 -ω ₂ - the second intermediate (difference) frequency;

ϕ _pr2 = ϕ _G2 -ϕ ₂ .

The voltage u _pr3 (t) from the input of the amplifier 20 of the second intermediate frequency is supplied to the input of the phase shifter 21 by -90 °, at the output of which a voltage is generated

u _CR4 (t) = U _CR2 cos [ω _CR2 t-ϕ _k (t) + ϕ _CR2 + 90 ° -90 °] = U _CR2 cos [ω _CR2 t-ϕ _k (t) + ϕ _CR2 ], 0≤ t≤T _s .

Voltages u _pr2 (t) and u _pr 4 (t) from the output of amplifier 14 and phase shifter 21 by -90 ° are supplied to two inputs of the first adder 22, at the output of which the first total voltage is formed

u _Σ1 (t) = U _Σ1 cos [ω _CR2 t-ϕ _k1 (t) + ϕ _CR2 ], 0≤t≤T _s ,

where U _Σ1 = 2U _pr2 ,

which is fed to the second input of the multiplier 23. At the output of the latter, a harmonic voltage is generated

u ₁ (t) = U ₁ cos (ω _Г2 t + ϕ _Г2 ), 0≤t≤T _c ,

;Where

;

K ₂ - transfer coefficient of the multiplier,

which is allocated by a narrow-band filter 24 (tuning frequency ω _n which is chosen equal to the frequency of the second local oscillator 2.2 ω _n = ω _G2 ), is detected by the amplitude detector 25 and is fed to the control input of the key 26, opening it. In the initial state, the key 26 is always closed.

The voltage u _Σ (t) from the output of the adder 22 through the public key 26 is supplied to the input of the clipper 15, where it is clipped and recorded in the buffer memory 16. The registration is synchronized by standard 1 frequency and time.

In the second step (when transmitting the signal from point B), the switch 4 must be open and the signal α ₃ from the generator 3 through the clipper 10 enters the same memory 11. The relay signal α _{4 is} recorded, like α ₂ , in the memory 16.

At an arbitrary point in time t ₃ ^V = t ₂ ^V + Θ, a noise-like microwave signal (signal (β ₃ ) is generated and recorded in a similar manner by the clock of the second point. The generated signal is converted to a frequency ω _1, amplifies it by power, emits an amplified signal in the direction the same satellite repeater.

At the same time t ₃ ^B = t ₃ ^A , the same noise-like microwave signal (signal α ₃ ) is formed using the same code sequence using the same code sequence. Register it at the first point A. Accept the on-board equipment of the satellite relay signal at a frequency of ω ₁ (signal α ₃ ), re-emit it to points A and B at a frequency of ω ₂ while maintaining phase relationships, receive a relay signal at both points, convert it to video frequency, recorded at time t ₄ ^A and t ₄ ^B, respectively (signal α ₄ , β ₄ ).

The correlation processing of two pairs of registered signals in the meter 17 determines at each point the following time delays:

τ _t = β ₁ ⊗ β ₂ = t ₂ ^B -t ₁ ^B = a ₁ + b ₂ + (Δ _В ^И + Δ _В ^П + ΔS) + Δt,

τ ₂ = α ₃ ⊗ α ₄ = t ₄ ^A -t ₃ ^A = a ₃ + b ₂ + (Δ _B ^AND + Δ _A ^P + ΔS) -Δt,

τ ₃ = α ₁ ⊗ α ₂ = t ₂ ^A -t ₂ ^A = a ₁ + a ₂ + (Δ _Ф ^И + Δ _А ^П + ΔS),

τ ₄ = β ₃ ⊗ β ₄ = t ₄ ^B -t ₃ ^B = b ₂ + b ₃ + (Δ _B ^AND + Δ _B ^P + ΔS),

and the corresponding interference frequencies F _i (i = 1, 2, 3, 4), which determine the derivatives of these delays:

,

,

,Where

,

a _j , b _j (j = 1, 2, 3) is the propagation time of the signal between the satellite and points A and B, respectively (Fig. 1);

Δ _A ^AND , Δ _B ^AND - signal delays in the radiating equipment of both points;

Δ _A ^P , Δ _V ^P - signal delay in the receiving and recording equipment;

ΔS - signal delay in the onboard satellite repeater;

Δt = t ₁ ^B -t ₁ ^A is the desired difference in the clock readings at the same physical moment.

,

, получаем:Assuming a _j and b _j linear functions with derivatives

,

we get:

,

,

Where

,

,

,

,

,

,

,

,

Δ _{A, B} ', Δ _{A, B'} ^'_ signal delay in the atmosphere at frequencies ω ₁ and ω _2, respectively;

ν - relativistic correction (Sagnac effect);

ω is the angular velocity of the Earth;

c is the speed of light;

D is the area of the quadrangle OA'S'B ', formed in the equatorial plane by the center of mass of the Earth, the projections of points A, B and the satellite S.

Corrections γ on the mobility of the satellite repeater during a single measurement is most easily reduced to zero by the corresponding choice of the free parameter Θ:

,

,

which should be calculated at the beginning of measurements by approximate ephemeris data, and then clarified by the results of current measurements.

As for the correction δ for hardware delays, it can be found by calibration using the “zero base” method.

The atmospheric correction ε is also taken into account.

At point B, the equipment works similarly, only the order of steps there is the opposite. To calculate the difference between the clock readings Δt, it is now sufficient to exchange the received digital data between the points, which can be done via ordinary telephone or telegraph communication channels.

The above operation of the device that implements the proposed method, corresponds to the reception of useful signals on the main channel at a frequency of ω ₂ (Fig. 4).

If the noise-like signal is received by the image channel at frequency ω _H

u _З (t) = U _З cos [ω _З t + ϕ _K2 (t) + ϕ _З ], 0≤t≤T _З ,

the amplifiers 14 and 20 of the second intermediate frequency are allocated the following voltages:

u _PR5 (t) = U _PR5 cos [ω _PR2 t + ϕ _K2 (t) + ϕ _PR5 ],

u _PR6 (t) = U _PR5 cos [ω _PR2 t + ϕ _K2 (t) + ϕ _ПP5 -90 °], 0≤t≤T _З ,

;Where

;

ω _PR2 = ω _З -ω _G2 - the second intermediate (difference) frequency;

ϕ _PR5 = ϕ _З ^_ ϕ _Г2 .

The voltage u _PR6 (t) from the output of the amplifier 20 of the second intermediate frequency is supplied to the inputs of the phase shifters 21 by -90 ° and 27 by + 90 °, at the output of which the following voltages are generated:

u _PR7 (t) = U _PR5 cos [ω _PR2 t + ϕ _K2 (t) + ϕ _PR5 -90 ° -90 °] = - U _PR5 cos [ω _PR2 t + ϕ _K2 (t) + ϕ _PR5 ],

u _PR8 (t) = U _PR5 cos [ω _PR2 + ϕ _K2 (t) + ϕ _PR5 -90 ° + 90 °] = U _PR5 cos [ω _PR2 t + ϕ _K2 (t) + ϕ _K2 (t) + ϕ _PR5 ], 0≤t≤T _Z.

The voltage u _PR5 (t) and u _PR7 (t) supplied to the two inputs of the adder 22 are compensated at its output.

Voltages u _PR5 (t) and u _PR8 (t) are supplied to two inputs of the adder 28, the output of which forms the second total voltage

u _Σ2 (t) = U _Σ cos [ω _PR2 t + ϕ _K2 (t) + ϕ _PR5 ], 0≤t≤T _З ,

where U _Σ2 = 2U _PR5 ,

which is fed to the second input of the second multiplier 29, to the first input of which a received noise-like signal u ₃ (t) is supplied from the output of the second power amplifier 12. The output of the multiplier 29 produces a harmonic voltage

u ₂ (t) = U ₂ cos (ω _Г2 t + ϕ _Г2 ), 0≤t≤T _З ,

,Where

,

which is allocated by the second narrow-band filter 30, is detected by the second amplitude detector 31 and is supplied to the control input of the second key 32, opening it. In the initial state, the keys 32, 38 and 44 are always closed.

It should be noted that the tuning frequency ω _{Н1 of} the narrow-band filter 30 is chosen equal to the frequency of the second local oscillator 22 ω _Н1 = ω _Г2 , and the frequency ω _{Н2 of the} tuning of narrow-band filters 36 and 42 is chosen equal to the second harmonic of the frequency of the second local oscillator 22 ω _Н2 = 2ω _Г2 .

The second total voltage u _Σ2 (t) from the output of the second adder 28 through the open second key 32 is fed to the input of the second clipper 33, where it is clipped and written to the second buffer memory 34. The registration is synchronized by the frequency and time standard 1. Then, the time delay of the arrival of the same noise-like signal at a frequency of ω _З to the first A and third C is determined by synchronization points by the method of correlation processing of registered signals, the magnitude of which is used to compare time scales.

If a noise-like signal

u _K1 (t) = U _K1 cos [ω _K1 t + ϕ _K3 (t) + ϕ _K1 ], 0≤t≤T _K1 ,

is received on the first combinational channel at a frequency ω _K1 , then the amplifiers 14 and 20 of the second intermediate frequency distinguish the following voltages:

u _PR9 (t) = U _PR9 cos [ω _PR2 t-ϕ _K3 (t) + ϕ _PR9 ],

u _PR10 (t) = U _PR9 cos [ω _PR2 t-ϕ _K3 (t) + ϕ _PR10 + 90 °], 0≤t≤T _K1 ,

;Where

;

ω _PR2 = 2ω _Г2 -ω _К1 - the second intermediate (difference) frequency;

ϕ _PR9 = ϕ _G2 -ϕ _K1 .

The voltage u _PR10 (t) from the output of the amplifier 20 of the second intermediate frequency is supplied to the inputs of the phase shifters 21 by -90 ° and 27 by + 90 °, at the output of which the following voltages are generated:

u _PR11 (t) = U _PR9 cos [ω _PR2 t-ϕ _K3 (e) + ϕ _PR9 + 90 ° -90 °] = U _PR9 cos [ω _PR2 t-ϕ _K3 (t) + ϕ _PR9 ],

U _PR12 (t) = U _PR9 cos [ω _PR2 t-ϕ _K3 (t) + ϕ _PR9 -90 ° + 90 °] = - U _PR9 cos [ω _PR2 t-ϕ _K3 (t) + ϕ _PR9 ], 0 ≤t≤T _K1 ,

The voltage u _PR9 (t) and u _PR12 (t) supplied to the two inputs of the adder 28 are compensated at its output.

Voltages u _PR9 (t) and u _PR11 (t) are supplied to two inputs of the adder 27, the output of which forms the third total voltage

u _Σ3 = U _Σ3 cos [ω _PR2 t-ϕ _K3 (t) + ϕ _PR9 ], 0≤t≤T _K1 ,

where U _Σ3 = 2U _PR9 ,

which is fed to the second input of the first multiplier 23, to the second input of which a received noise-like signal u _K1 (t) is supplied from the output of the second power amplifier 12. The output of the multiplier 23 produces a harmonic voltage

u _З (t) = U _З cos (2ω _Г2 t + ϕ _Г2 ), 0≤t≤T _K1 ,

;Where

;

which is allocated by the third narrow-band filter 36, is detected by the third amplitude detector 31 and is fed to the control input of the third key 38, opening it. In this case, the total voltage u _Σ3 (t) from the output of the adder 22 through the public key 38 is supplied to the input of the clipper 39, where it is clipped and recorded in the third buffer storage device 40. The registration is synchronized by the frequency and time standard 1. Then determine the time delay of the arrival of the same noise-like signal at a frequency ω _K1 in the first A and fourth D synchronization points by the method of correlation processing of recorded signals, the magnitude of which is used to compare time scales. If a noise-like signal

u _K2 (t) = U _K2 cos [ω _PR2 t + ϕ _K4 (t) + ϕ _K2 ], 0≤t≤T _K2 ,

is taken along the second combinational channel at a frequency ω _K2 (Fig. 4), then the following voltages are allocated by amplifiers 14 and 20 of the second intermediate frequency:

u _PR13 (t) = U _PR13 cos [ω _PR2 t + ϕ _K4 (t) + ϕ _PR13 ],

u _PR14 (t) = U _PR13 cos [ϕ _PR2 t + ϕ _K4 (t) + ϕ _PR13 -90 °], 0≤t≤T _K2 ,

;Where

;

ω _PR2 = ω _K2 -2ω _G2 - the second intermediate (difference) frequency;

ϕ _PR13 = ϕ _K2 -ϕ _G2 .

The voltage u _PR14 (t) from the output of the amplifier 20 of the second intermediate frequency is supplied to the inputs of the phase shifters 21 by -90 ° and 27 by + 90 °, at the output of which the following voltages are generated:

U _PR15 (t) = U _PR13 cos [ω _PR2 t + ϕ _K4 (t) + ϕ _PR13 -90 ° -90 °] = - U _PR13 cos [ω _PR2 t + ϕ _K4 (t) + ϕ _PR13 ],

u _PR16 (t) = u _PR13 cos [ω _PR2 t + ϕ _K4 (t) + ϕ _PR13 -90 ° + 90 °] = U _PR13 cos [ω _PR2 t + ϕ _K4 (t) + ϕ _PR13 ].

The voltage u _PR13 (t) and u _PR15 (t) supplied to the two inputs of the adder 22 are compensated at the output.

Voltages u _PR13 (t) and u _PR16 (t) are supplied to two inputs of the adder 28, the output of which forms the fourth total voltage

u _Σ4 (t) = U _Σ4 cos [ω _PR2 t + ϕ _K4 (t) + ϕ _PR13 ], 0≤t≤T _K2 ,

where U _Σ4 = 2U _PR13 ,

which is fed to the second input of the second multiplier 29, to the first input of which a received noise-like signal u _K2 (t) is supplied from the output of the second power amplifier 12. The output of the multiplier 29 produces a harmonic voltage

u ₄ (t) = U ₄ cos (2ω _Г2 t + ϕ _Г2 ), 0≤t≤T _K2 ,

,Where

,

which is allocated by the fourth narrow-band filter 42, is detected by the fourth amplitude detector 43 and is supplied to the control input of the key 44, opening it. In this case, the total voltage u _Σ4 (t) from the output of the adder 28 through the public key 44 is supplied to the input of the clipper 45, where it is clipped and recorded in the fourth buffer storage device 46. The registration is synchronized by the frequency and time standard 1. Then determine the time delay of arrival of the same noise-like signal at a frequency ω _K2 in the first A and fifth E synchronization points by the method of correlation processing of recorded signals, the magnitude of which is used to compare time scales.

To distinguish characteristic ionospheric disturbances, a number of TECs are subjected to special filtering in a range of periods corresponding to the scale of the disturbance.

For this, the voltage from the output of the switches 26 and 44, 26 and 32, 26 and 38 is supplied to the inputs of the signal processing units 48.1, 48.2 and 48.3, where the data on the total electronic content in the Earth’s ionosphere are analyzed. In blocks 49.1, 49.2, and 49.3, time series of the total electronic content are formed corresponding to the responses of the ionosphere to the action of the ionospheric disturbance source.

For each pair of checked values (α, v), the radiation pattern of the receiving system is formed and accordingly oriented in the phase space [α, v], due to the common-mode summation in the adder of 50 separate rows ΔY _c (t) of the receiving system

where p is the number of antennas of the receiving system,

the time shift τ _i is defined as the difference between the time t _j , the j-th count of the i-th total TEC series and the time t _{0 of} recording the ionospheric disturbance of the central antenna of the receiving system τ _i = t _j -t ₆ , and is selected based on the minimization of the expression describing the dynamics outrage

where Ap, is the distance traveled by the wave front between the ith and the central element of the receiving system.

For extended receiving systems, the distance Δp _{i is} calculated taking into account the curvature of the Earth. To this end, in a given direction α of the arrival of the ionospheric disturbance wave at a height h _max, a remote point source (indicated by point E in Fig. 5) is set, which will be the pole of the orthodromic coordinate system, the equator of which (the strong bold line in Fig. 5) passes through the central element of the receiving system (point A in Fig. 5). Then the front of the wave propagating from a remote point source and passing through the ith element of the receiving system (point B in Fig. 5) will be a latitudinal circle (a thick broken line) parallel to the equator of the resulting orthodromic system. Such a model corresponds to a plane wave of ionospheric disturbance propagating over the Earth's sphere.

The geometrical coordinates (X _c , Y _c , Z _c ) of the remote source of the ionospheric disturbance are determined using the rules of spherical trigonometry. In this case, a spherical triangle is considered, the vertex A of which is the central element of the receiving system with known coordinates (X _o , Y _o , Z _o ). The vertex C of this triangle is the north pole of the geocentric coordinate system (O, O, R + h _max ), where R is the radius of the Earth. It is necessary to determine the coordinates of the third vertex E, which will be the remote source. So that the remote source E is the pole of the orthodromic coordinate system, the angular size of the side AE of the spherical triangle is set to π / 2. In the obtained spherical triangle, two sides AC and AE are known, as well as the angle between them <LCAE = α, which is a typical task of a spherical triangle. Using the cosine theorem of the sides of a spherical triangle, the third side and the coordinates (X _c , Y _c , Z _c ) of the remote source E.

The decision on the correctness of the system under test is made when the total signal exceeds a predetermined threshold level in the threshold block 51. It is believed that an ionospheric disturbance is detected, and the α and v values determined in computer 52, for which the total signal of the receiving system exceeded the threshold value, are considered estimates of the direction of arrival and phase velocity of the detected ionospheric disturbance.

The clock synchronization method allows you to:

- achieve extreme measurement accuracy (about ± 0.1 ns) using VLBI technology and relay technology, which is already widely used in practice;

- to form the microwave signals necessary for the measurement at ground points, which makes it possible to gradually increase the accuracy of measurements by optimizing the signal structure and improving the ground-based recording technique without interfering with the satellite onboard equipment;

- increase the efficiency of measurements, i.e. bring the time interval from the beginning of measurements to obtain results up to several tens of seconds (almost to the time of correlation signal processing);

- to avoid the installation on board of a satellite of highly stable time-keepers and time interval meters, to limit the on-board equipment to only a phase-stable microwave signal relay system.

Thus, the proposed method and device, in comparison with prototypes and other technical solutions of a similar purpose, provides the determination of the propagation velocity and direction of arrival of the ionospheric disturbance caused by various destabilizing factors by restoring the spatial distribution of the total electronic content according to atmospheric radio-transmission data by relayed signals.

Thus, the functionality of known technical solutions is expanded.

Claims (2)

1. A clock synchronization method based on the simultaneous reception of noise-like microwave signals from an artificial Earth satellite by spaced ground points, their coherent conversion to a video frequency, digital recording of received signals and determining the time delay of the arrival of the same signal to synchronization points by correlation processing of recorded signals for which the magnitude comparison of time scales produce, while at the initial time t ₁ to the clock of the first item using the code pos edovatelnosti form a noise-like microwave signal is recorded it at the same point, the conditioned signal is converted to a frequency ω _1, increase its power emit the amplified signal in the direction of artificial Earth relay satellite in the same time t _1, the clock of the second paragraph using the same code sequence form the same noise-like microwave signal, it is recorded in the second paragraph, taking onboard equipment Earth relay artificial satellite signal at frequency ω _1, n reemit first and second points at the frequency ω ₂ while preserving phase relationships, at an arbitrary time point t _3, the clock of the second paragraph similarly formed and recorded noise-like microwave signal generated signal is converted to a frequency ω _1, increase its power emit the amplified signal in the direction of the same artificial satellite repeater earth, in the same moment of time t ₃ by the clock of the first item by using the same code sequence form the same noise-like microwave signal, it is recorded in the first paragraph, taking t noise-like signal in the main channel at frequency ω _2, is converted in frequency using the voltage of the second local oscillator and a voltage of the second local oscillator shifted in phase by + 90 °, isolated first and second voltage of the second intermediate frequency, a second voltage of the second intermediate frequency is shifted in phase by -90 °, summarized with the first voltage of the second intermediate frequency, multiplied the obtained first total voltage with the received noise-like signal, emit the harmonic voltage at a frequency ω _{G2 of the} second hetero dyne, detect it and use it to allow further processing of the received signal, the received noise-like signal through a mirror channel at a frequency ω _{З is} converted in frequency using the voltage of the second local oscillator and the voltage of the second local oscillator phase-shifted by + 90 °, the third and fourth voltages of the second intermediate frequency, respectively, shift the fourth voltage of the second intermediate frequency by + 90 °, sum with the third voltage of the second intermediate frequency, multiply the resulting second mmar voltage with a received noise-like voltage, a second harmonic voltage is isolated at a frequency ω _{Г2 of the} second local oscillator, it is detected and used to enable digital recording of the second total voltage, the time delay of the arrival of the same signal at a frequency ω _З to the first and third synchronization points is determined by the method correlation processing of recorded signals, the magnitude of which compares the time scales, receive a noise-like signal on the first combinational channel at ot ω _K1 , is frequency-converted using the voltage of the second local oscillator and the voltage of the second local oscillator phase-shifted by + 90 °, the fifth and sixth voltages of the second intermediate frequency are isolated, the sixth voltage of the second intermediate frequency is shifted by -90 °, summed with the fifth voltage second intermediate frequency, multiplies the resultant third total voltage with the received spread spectrum signal, allocate the third harmonic voltage at frequency 2ω _T2 of the second local oscillator is detected and it is used To permit digital recording third total voltage, determine the time delay of arrival of the same signal at ω _K1 frequency in the first and fourth paragraphs synchronization by correlation processing for the signals, the magnitude of which produce a comparison of time scales, taking a noise-like signal to the second Raman channel at frequency ω _K2 , is converted in frequency using the voltage of the second local oscillator and the voltage of the second local oscillator, phase shifted by + 90 °, the seventh and eight my voltage of the second intermediate frequency, respectively, shift the eighth voltage of the second intermediate frequency by + 90 °, sum with the seventh voltage of the second intermediate frequency, multiply the resulting fourth total voltage with the received noise-like signal, emit the fourth harmonic voltage at a frequency of 2ω _{G2 of the} second local oscillator, detect it and used to enable digital recording of the fourth total voltage, determine the time delay of arrival of the same signal at a frequency ω _K2 to the first and fifth synchronization points by the method of correlation processing of recorded signals, the magnitude of which compares time scales, characterized in that they analyze the data on the total electronic content in the Earth’s ionosphere, which are obtained as a result of processing signals received by two-frequency receivers of ground points, with subsequent formation time series of the complete electronic content and their filtration in the range of oscillation periods corresponding to the response of the ionosphere to the source an onospheric disturbance, an extended receiving antenna system is used and the hypothesis about the values of the direction of arrival and the propagation velocity of the plane front of the ionospheric disturbance is verified by forming the radiation pattern of the receiving system and scanning it in a given sector of the space viewing “arrival direction - velocity of propagation of the ionospheric disturbance” due to synthesis of the output signal of the receiving system during in-phase summation of the series of variation of the total electronic content of individual antennas of the system with time offsets calculated based on the verified values of the direction of the ionospheric disturbance and the distances traveled by the front of the ionospheric disturbance between the antennas of the system in the checked direction inside the spherical layer of the Earth’s ionosphere, the decision on the correctness of the hypothesis being tested and the detection of the ionospheric disturbance is made when the total signal exceeds the specified threshold level, corresponding values of the direction of arrival and phase velocity of ionospheric propagation perturbations are considered estimates. 2. A clock synchronization device containing a geostationary satellite repeater, first and second ground stations, each of which contains a frequency and time standard, a first local oscillator, a first mixer, the second input of which is connected via a switch to the first output of the pseudo-random signal generator, the first amplifier intermediate frequency, the first power amplifier, duplexer, the input-output of which is connected to the transceiver antenna, the second power amplifier, the second mixer, the second input of which is black the second local oscillator is connected to the first output of the frequency and time standard, the first amplifier of the second intermediate frequency, the first adder, the first multiplier, the second input of which is connected to the output of the second power amplifier, the first narrow-band filter, the first amplitude detector, the first switch, the second input of which is connected to the output of the first adder, the second clipper, the second input of which is connected to the third output of the frequency and time standard, a second buffer memory and a first meter of delays and their derivatives, output One of which is the first output of a ground station, the first clipper, the second input of which is connected to the second output of the frequency and time standard, and the first buffer storage device, the output of which is connected to the second input of the delay meter and their derivatives, are connected in series to the second output of the pseudo-random signal generator connected to the output of the second local oscillator, the first phase shifter + 90 °, the third mixer, the second input of which is connected to the output of the second power amplifier, the second amplifier the second intermediate frequency and the second phase shifter -90 °, the output of which is connected to the second input of the first adder, connected in series to the output of the second amplifier of the second intermediate frequency, the third phase shifter + 90 °, the second adder, the 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, the second narrow-band filter, the second amplitude detector, the second switch, the second input of which is connected to the output of a third adder, a third clipper, the second input of which is connected to the third output of the frequency and time standard, a third buffer memory and a third meter of delays and their derivatives, the second input of which is connected to the output of the first buffer memory, and the output is the second output of a ground station, the output of the first multiplier is connected in series with a third narrow-band filter, a third amplitude detector, a third key, the second input of which is connected to the output of the first adder, the fourth clipper, W the second input of which is connected to the third output of the frequency and time standard, the fourth buffer memory and the third meter of delays and their derivatives, the second input of which is connected to the output of the first buffer memory, and the output is the third output of a ground station, the fourth is connected in series to the second multiplier narrow-band filter, fourth amplitude detector, fourth key, the second input of which is connected to the output of the second adder, the fifth clipper, the second input of which is connected is connected with the third output of the frequency and time standard, the fifth buffer memory and the fourth meter of delays and their derivatives, the second input of which is connected to the output of the first buffer memory, and the output is the fourth output of a ground station, characterized in that it is equipped with three signal processing units , three blocks for the formation of time series of full electronic content, a third adder, a threshold block and a computer, and the first key is connected in series to the first a signal processing unit, the second input of which is connected to the output of the fourth key, the first block for generating time series of full electronic content, the third adder, the threshold unit and the computer, the second input of which is connected to the antenna control unit, the second signal processing unit is connected in series to the output of the first key, the second input of which is connected to the output of the second key, and the second block for generating time series of full electronic content, the output of which is connected to the second input of the third adder, to the outputs The third signal processing unit, the second input of which is connected to the output of the third key, and the third block of generating time series of the complete electronic content, the output of which is connected to the third input of the third adder, are connected in series to the first key.

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