RU2612127C2 - Method for clock synchronization and device for its implementation - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: device for synchronizing clocks that implements the inventive method comprises a center (40) for information processing and three ground points A, B and C, each of which comprises a standard (1) of frequency and time, heterodynes (2.1 and 2.2), a generator (3 ) of pseudorandom signals, a switch (4), mixers (5, 13, 19, 28, 30), an amplifier (6) of the first intermediate frequency, power amplifiers (7 and 12.1), a diplexer (8), a two-way transmission antenna (9), clippers (10 and 15), buffer memories (11 and 16), a meter (17) of delays and their derivatives, a phase shifter (18) for 90°, amplifiers (14 and 20) of the second intermediate frequency, a phase shifter (21) for -90°, an adder (22), multipliers (23 and 34), a narrowband filter (24) and an amplitude detector (25), a key (26), a unit (27) of reference frequencies, an amplifier (19) of the third intermediate frequency, filters (31 and 35 ) lower frequencies, a meter (32) of Doppler frequency, a correlator (33), an optimizing peak-holding controller (36), a unit (37) of variable delay, a indicator (38) of distance and communication lines (39.1, 39.2, 39.3). The information processing center contains phase doublers (41.1, 41.2 and 41.3), dividers (42.1, 42.2 and 42.3) of phase by two, narrow-band filters (43.1, 43.2 and 43.3), phase meters (44.1, 44.2 and 44.3), correlators (45.1, 45.2 and 45.3), multipliers (46.1, 46.2 and 46.3), filters (47.1, 47.2 and 47.3) of lower frequencies, optimizing peak-holding controllers (48.1, 48.2 and 48.3), adjustable delay units (49.1, 49.2 and 49.3) and a computer (50).

EFFECT: improved accuracy of synchronization of remote time scales by precise and unambiguous measurement of angular coordinates of the satellite relay and improved accuracy of determination of its location and movement in space.

2 cl, 6 dwg

Description

The proposed method and device relates to communication 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. 591799, 614416, 970300, 1180835, 1244632, 1278800; RF patents No. No. 2000143, 2003157, 2010035, 2177167, 2292574, 2386159, 2439643, 2538405, 2535653, 2539914; US patents No. 7327699, 7426156, 8145247; British patents No. 1517661, 1526467; German patent No. 3278943; patent EP No. 0564220 and others).

Of the known methods and devices closest to the proposed are the "Method of clock synchronization and a device for its implementation (RF patent No. 2535653, G04C 11/00, 2013), which are selected as prototypes.

The known 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.

The main advantage of the duplex communication method is that it eliminates the length of the signal path. Therefore, its accuracy mainly depends on the parameters of the onboard transponder, the type of signal used, the technique for measuring time intervals, the distance from a ground station to a satellite repeater, the speed and direction of its movement relative to ground points, which are determined by the Doppler shift of the carrier frequency of the signals used.

An object of the invention is to increase the accuracy of synchronization of remote time scales by accurately and unambiguously measuring the angular coordinates of the satellite repeater and determining its location and movement in space.

The problem is solved in that the clock synchronization method, based, in accordance with the closest analogue, on the simultaneous reception by separated points of noise-like microwave signals from the artificial Earth satellite, coherently converting them to a video frequency, digitally recording the received signals and determining the time delay of arrival of one and of the same signal to synchronization points by the method of correlation processing of registered signals, the magnitude of which is used to compare 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 by power, emit an amplified signal in the direction of an artificial Earth repeater satellite, 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 artificial satellite and relay Earth signal at 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 retransmit noise-microwave signal generated signal is converted to the frequency ω ₁ , amplify it in power, emit an amplified signal in the direction of the same satellite repeater, at the same time t _3, according to the clock of the first point, using the same code sequence form the same noise-like microwave signal, reg it is abraded at the first point, the signal at the frequency ω _{1 is} received by the onboard equipment of the satellite repeater and re-emitted to the first and second points at the frequency ω ₂ while maintaining phase relationships, the received signal at the frequency ω _{2 is} converted in frequency using the voltage of the second local oscillator shifted in phase by + 90 °, the voltage of the second intermediate frequency is isolated, it is shifted in phase by -90 °, summed with the initial voltage of the second intermediate frequency, the resulting total voltage is multiplied with the received signal, output they produce a harmonic voltage at a frequency ω _{g2 of the} second local oscillator, detect it and use it to further process the received signal, differs from the closest analogue in that the resulting total voltage is converted in frequency using the voltage of the first reference frequency ω _E1 , the voltage of the third intermediate frequency is isolated

ω _pr3 = ω _pr2 + Ω _{d -ω E1} ,

convert it in frequency using the voltage of the second reference frequency

ω _E2 = ω _{pr2 -ω} E1 -Ω ₀ ,

where Ω ₀ is the frequency of the stand, which is introduced to determine the sign of the Doppler shift Ω _d , a low-frequency voltage is isolated

ω _N = Ω _D + Ω ₀ ,

measure the low frequency ω _Н and depending on whether ω _Н > Ω ₀ or ω _Н <Ω ₀ determine the sign of the Doppler shift, and therefore the direction of the radial velocity of the satellite repeater, the resulting total voltage is multiplied with a noise-like microwave signal passed through adjustable delay unit, allocate a low-frequency voltage proportional to the correlation function R (τ), where τ is the current time delay, change the time delay τ until the equality τ = τ _{З is} obtained, which corresponds to the maximum correlation value of the function R (τ), support it and determine the distance from the ground point to the satellite repeater according to the formula

,

,

where c is the propagation velocity of radio waves,

differs from the closest analogue in that they use a third ground station and an information processing center, and three ground stations are placed in the form of a geometric triangle, at the tops of which land stations are placed, and the sides form ultra-long measuring bases, signals received at ground stations are transmitted along the lines communication, for example fiber optic, to the information processing center, in which three processing channels are formed, in each of which phase-shift keying in received noise-like signals is eliminated, harmonic oscillations, measure the phase differences between them, forming the phase scales of the direction finding of the satellite repeater, accurate but ambiguous, at the same time the signal of the second processing channel is multiplied with the signal of the first processing channel passed through the first block of adjustable delay, a low-frequency voltage proportional to the first correlation function R (τ), where τ is the current time delay, the time delay τ is changed until the equality τ = τ _{1 is} obtained, which corresponds to the maximum value of the first correlation function and R ₁ (τ), support it and determine the first angle α on the satellite repeater according to the formula

,

,

where c is the propagation velocity of radio waves;

d ₁ - the distance between ground points A and B (extra-long measuring base),

the signal of the third processing channel is multiplied with the signal of the first processing channel passed through the second adjustable delay unit, a low-frequency voltage proportional to the second correlation function R ₂ (τ) is extracted, the time delay τ is changed until the equality τ = τ _{2 is} obtained, which corresponds to the maximum value of the second correlation functions R ₂ (τ), support it and determine the second angle on the satellite repeater according to the formula

,

,

where d ₂ is the distance between ground points A and C (extra-long measuring base), the signal of the second processing channel is multiplied with the signal of the third processing channel, passed through the third adjustable delay unit, a low-frequency voltage proportional to the third correlation function R ₃ (τ) is extracted, change the time delay τ until the equality τ = τ _{3 is} obtained, which corresponds to the maximum value of the third correlation function R ₃ (τ), support it and determine the third angle on the satellite repeater according to the formula

,

,

where d ₃ - the distance between ground points B and C (extra-long measuring base),

forming the time scales of direction finding of the satellite repeater, rough, but unambiguous.

The problem is solved in that the clock synchronization method according to claim 1 is characterized in that it is simultaneously received by spaced three ground points located in the form of a geometric triangle, radiation of quasars and other celestial bodies of near and far space, precisely and unambiguously determine direction finding angles in three planes and determine their location and movement in space.

The problem is solved in that the clock synchronization method according to p. 1 and 2 is characterized in that at the same time taken apart by four ground points, placed in the form of a geometric quadrangle with six ultra-long measuring bases, the radiation of quasars and other celestial bodies of near and far space, exactly and unambiguously measure direction finding angles in six planes and determine their location and movement in space.

The problem is solved in that 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 generator pseudo-random signal, amplifier of the first intermediate frequency, first power amplifier, duplexer, the input-output of which is connected to the transceiver antenna, second power amplifier, W 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 adder, the first multiplier, the second input of which is connected to the output of the second power amplifier, a narrow-band filter, an amplitude detector, a key, the second input of which connected to the output of the adder, a second clipper, the second input of which is connected to the second output of the frequency and time standard, a second buffer memory and a meter of delays and their derivatives, the output to otoroho is the output of a ground station, a pseudo-random signal generator, 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, serially 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 of the second intermediate frequency and the second phase shifter 90 °, the output of which is connected to the second input of the adder, the fourth mixer is connected in series to the key output, the second input of which is connected to the first output of the reference frequency unit, the amplifier of the third intermediate frequency, the fifth mixer, the second input of which connected to the second output of the block of reference frequencies, the first low-pass filter and a Doppler frequency meter, the second multiplier, the second low-pass filter are connected in series to the key output A signal, an extreme controller and an adjustable delay unit, the second input of which is connected to the output of the pseudo-random signal generator, the first output is connected to the second input of the second multiplier, and the second output is connected to the range indicator, differs from the closest analogue in that it is equipped with a third ground station and center information processing, and three ground points are placed in the form of a geometric triangle, at the tops of which ground points are placed, and three ultra-long measuring bases are formed by the sides , the information processing center is made in the form of three information processing channels connected to the outputs of the second power amplifiers, three ground points through the corresponding communication lines, with each information processing channel consisting of phase doublers, a phase divider into two and a narrowband connected to the output of the communication line filter, the outputs of the narrow-band filters of the first and second processing channels through the first phase meter are connected to the first input of the computer, the outputs of the narrow-band filters of the first and third channels The operation through the second phase meter is connected to the second input of the computer, the outputs of the narrow-band filters of the second and third processing channels through the third phase meter are connected to the third input of the computer, the first adjustable delay unit, the first multiplier, the second input of which is connected to the output, are connected in series to the output of the communication line of the first ground station communication lines of the second ground station, the first low-pass filter and the first extreme regulator, the output of which is connected to the second input of the first block of the adjustable rear A horn, the second input of which is connected to the fourth input of the computer, a second adjustable delay unit, a second multiplier, a second input of which is connected to the output of the communication line of the third ground point, a second low-pass filter and a second extreme regulator, are connected in series to the output of the communication line of the first ground station which is connected to the second input of the second adjustable delay unit, the second input of which is connected to the fifth input of the computer, to the output of the communication line of the third ground station in series dklyucheny third block of controlled delay, the third multiplier, a second input coupled to an output link of the second ground station, the third lowpass filter and a third extreme regulator whose output is connected to a second input of the third variable delay unit, a second output is connected to the sixth input of the computer.

The problem is solved in that the device for clock synchronization according to claim 4 is characterized in that it is equipped with quasars and other celestial bodies of near and far space, connected by radio channels to three ground stations.

The problem is solved in that the device for synchronizing the clock according to paragraphs 4 and 5 is characterized in that it is equipped with a fourth ground station, and four ground stations are placed in the form of a quadrangle, at the tops of which land points are placed, and six ultra-long measuring bases are formed by sides and diagonals connected by radio channels with quasars and other celestial bodies of near and far space.

The geometric arrangement of ground posts A, B, C and the satellite A relay S is shown in FIG. 1, where the following notation is introduced: d ₁ d ₂ , d ₃ - extra-long measuring bases, 40 - information processing center. Timing diagrams of the duplex clock comparison method are shown in FIG. 2, where the following notation is introduced: S, A, B are the time scales of the satellite repeater of ground points A and B, respectively. The structural diagram of the equipment of one of the ground points (A) that implements the proposed method for clock synchronization is shown in FIG. 3. A frequency diagram illustrating signal conversion is shown in FIG. 4. The block diagram of the information processing center is shown in FIG. 5.

The geometric arrangement of ground points A, B, C, D and the source of radio emissions (IRI) is shown in FIG. 6, where the following notation is introduced: d ₁ , d ₂ , d ₃ , d ₄ , d ₅ , d ₆ - extra-long measuring bases, 40 - information processing center.

The device for clock synchronization contains serially connected frequency and time standard 1, the first local oscillator 2.1, the first mixer 5, the second input of which is connected via the switch 4 to the first output of the pseudo-random signal generator, the amplifier 6 of the first intermediate frequency, the first power amplifier 7, duplexer 8, input - the output of which is connected to the transceiver antenna 9, a second power amplifier 12, a second mixer 13, the second input of which is connected through the second local oscillator 2.2 to the first output of frequency and time standard 1, the second amplifier 14 of the second intermediate frequency, the adder 22, the first multiplier 23, the second input of which is connected to the output of the second power amplifier 12, a narrow-band filter 24, the amplitude detector 25, key 26, the second input of which is connected to the output of the adder 22, the second clipper 15, the second the input of which is connected to the second output of the frequency and time standard 1, a second buffer memory 16 and a delay meter 17 and their derivatives, the output of which is the output of the ground station equipment.

A pseudo-random signal generator 3 is connected to the third output of the frequency and time standard 1, the first clipper 10, the second input of which is connected to the second output of the frequency and time standard 1, and the first buffer storage device 11, the output of which is connected to the second input of the delay meter 12 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 to -90 ⁹ , the output of which is connected to the second input the adder 22. To the output of the key 26 are connected in series with the fourth mixer 28, the second input of which is connected to the first output of the reference frequency unit 27, the amplifier 29 of the third intermediate frequency, the fifth mixer 30, the second input of which is connected with a second output of the reference frequency unit 27, a first low-pass filter 31 and a Doppler frequency meter 32. A second multiplier 34, a second low-pass filter 35, an extremal regulator 36, and an adjustable delay unit 37 are connected to the output of the key 26, the second input of which is connected to the output of the pseudo-random signal generator 3, the first output is connected to the second input of the second multiplier 34, and the second output is connected to 38 range indicator.

A second multiplier 34, a second low pass filter 35, an extremal regulator 36, and an adjustable delay unit 37 form a correlator 33.

The information processing center 40 is made in the form of three information processing channels connected to the outputs of the second power amplifiers 12.1, 12.2 and 12.3 of the power of three ground stations A, B and C through the corresponding communication lines 39.1, 39.2 and 39.3. In this case, the information processing channel consists of a phase doubler 41.1 (41.2, 41.3) connected in series to the communication line 39.1 (39.2, 39.3), a phase divider into two 42.1 (42.2, 42.3) and a narrow-band filter 43.1 (43.2, 43.3). The outputs of the narrow-band filters 43.1 and 43.2 of the first and second processing channels through the first phase meter 44.1 are connected to the first output of the computer 50. The outputs of the narrow-band filters 43.1 and 43.3 of the first and third processing channels through the second phase meter 44.2 are connected to the second input of the computer 50. The outputs of the narrow-band filters 43.2 and 43.3 the second and third processing channels through the third phase meter 44.3 are connected to the third input of the computer 50. To the output of the communication line 39.1 of the first ground station, the first adjustable delay unit 49.1 is connected in series, the first a multiplier 46.1, the second input of which is connected to the output of the delay line 39.2 of the second ground station, the first low-pass filter 47.1 and the first extreme controller 48.1, the output of which is connected to the second input of the first block 49.1 adjustable delay, the second input of which is connected to the fourth input of the computer 50. K the input of the communication line 39.1 of the first ground station is connected in series with the second block 49.2 adjustable delay, the second switch 46.2, the second input of which is connected to the output of the communication line 39.3 of the third ground station, the second a low-pass filter 47.2 and a second extreme controller 48.2, the output of which is connected to the second input of the second adjustable delay unit 49.2, the second output of which is connected to the fifth input of the computer 50. The third adjustable delay unit 49.3, the third multiplier are connected in series to the output of the communication line 39.2 of the third ground station 46.3, the second input of which is connected to the output of the delay line 39.2 of the second ground station, the third low-pass filter 47.3 and the third extreme controller 48.3, the output of which is connected to the second input of the third about block 49.3 adjustable delay, the second output of which is connected to the sixth input of the computer 50.

Switch 46.1 (46.2, 46.3), low-pass filter 47.1 (47.2, 47.3), extreme regulator 48.1 (48.2, 48.3) and adjustable delay unit 49.1 (49.2, 49.3) form the correlator 45.1 (45.2, 45.3).

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

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

φ _k (t) = {0, π} - manipulated component phase mapping law phase shift keying in accordance with the code sequence M (t), wherein φ _k (t) = const at kτ _E <t <(k + 1) τ _Oe and can change abruptly at t = kτ _Oe , 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 = Nτ _E ) in generator 3 using standard 1 frequency and time.

The specified signal is supplied to the input of the clipper 10, and then is 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 + 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 [ω _np1 t + ϕ _k (t) + ϕ _CR1 ], 0≤t≤T _c ,

Where

,

,

K 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, is transmitted through the duplexer 8 and the transceiver antenna 9 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 B (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 _c .

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

u ₂ (t) = U ₂ cos [(ω ₂ ± Ω _Д ) (t-τ _P ) + ϕ _k (t-τ _З ) + ϕ ₂ ], 0≤t≤T _c ,

where ± 'Ω is the Doppler frequency shift;

- время запаздывания ретранслированного сигнала относительно запросного;

- the delay time of the relay signal relative to the request;

R is the distance from the ground point to the satellite repeater;

C is the propagation velocity of radio waves,

it is received by the transmitting and receiving 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 mixer and the first 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 cos (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 by the value of the second intermediate frequency (Fig. 4)

w _{G1 G2} -ω = ω _WP2.

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

u _p2 (t) = U _p2 cos [(ω _p2 ± Ω _D ) (t-τ _З ) + ϕ _k (t-τ _З ) + ϕ _pr2 ],

u _p2 (t) = U _p2 cos [(ω _p2 ± Ω _D ) (t-τ _З ) + ϕ _k (t-τ _З ) + ϕ _pr2 + 90 °], 0≤t≤T _c ,

;Where

;

K ₁ - gear ratio of the mixer

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

ϕ _pr2 = ϕ _G2 -ϕ ₂ .

The voltage u _p3 (t) from the output 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 _p2 (t) = U _p2 cos [(ω _p2 ± Ω _D ) (t-τ _З ) + ϕ _k (t-τ _З ) + ϕ _pr2 + 90 ° -90 °] =

= U _pr2 cos [(ω _np2 t ± Ω _D ) + ϕ _k (t-τ _З ) + ϕ _pr2 ].

The _voltages u _p2 (t) and u _p4 (t) from the output of the amplifier 14 of the second intermediate frequency and the phase shifter 21 by -90 ° are supplied to the two inputs of the adder 22, the output of which forms the total voltage

u _∑ (t) = U _∑ cos [(ω _np2 ± Ω _D ) + ϕ _k (t-τ _З ) + ϕ _np2 ], 0≤t≤I _c ,

where U _∑ = 2U _p2 ,

which goes to the second input of the first multiplier 23. At the output of the last, a harmonic voltage is generated

u ₁ (t) = U ₁ cos (ω _U2 t + ϕ _Г2 ), 0≤t≤T _c ,

;Where

;

K ₂ is the transmission coefficient of the multiplier, which is allocated by a narrow-band filter 24 (the tuning frequency ω _{n of} which is chosen equal to the frequency ω _{G2 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.

In this case, the voltage u _∑ (t) from the output of the adder 22 through the public key 26 is supplied simultaneously to the first input of the second clipper 15, the fourth mixer 28 and the second multiplier 34. In the second clipper 15, the indicated total voltage u _∑ (t) is clipped and then recorded into the second storage device 16. Registration is synchronized by standard 1 frequency and time.

To determine the speed and direction of movement of the satellite repeater relative to the ground point, it is necessary to measure the Doppler frequency shift ± Ω ' _D. For this, multiple conversion of the frequency of the received signal is used. It is necessary because the relative value of the Doppler shift 'Ω _D / ω ₂ , equal to the ratio of velocities V _R / c, where V _R is the radial component of the velocity of the satellite repeater, c is the propagation velocity of the radio waves, does not exceed 10 ^-4 . Under these conditions, the separation of the Doppler shift during a single frequency conversion of the received signal requires the use of circuits with a very high, almost unattainable quality factor.

The total voltage u _∑ (t) from the output of the adder 22 through the public key 26 is supplied to the first input of the fourth mixer 28, the second input of which is supplied with the voltage of the first reference frequency ω _E1 from the first output of the block 27 of the reference frequencies. At the output of the mixer 28, voltages of combination frequencies are generated. The amplifier 29 is allocated the voltage of the third intermediate frequency

ω _pr3 = ω _pr2 + Ω _{D -ω E1} ,

which is fed to the first input of the fifth mixer 30. The second input of the last voltage of the second reference frequency

ω _E2 = ω _{pr2 -ω} E1 -Ω ₀ ,

where 'Ω ₀ is the frequency of the stand, which is introduced to determine the sign of the Doppler shift' Ω ₀ . The nominal frequency of the stand is selected from the condition

.

.

At the output of the mixer 30, voltages of combination frequencies are generated. Low-pass filter 31 provides low-frequency voltage

ω _n = Ω _D + Ω ₀ ,

which is fed to the input of the Doppler frequency meter 32, where the measurement of the Doppler bias' Ω _D.

Moreover, depending on whether ω _n >'Ω ₀ or ω _n <' Ω ₀ determine the sign of the Doppler shift, and therefore the direction of the radial velocity of the satellite repeater.

The total voltage u _∑ (t) is also supplied to the first input of the second multiplier 34, the second input of which from the output of the pseudo-random signal generator 3 is fed a noise-like microwave signal u _c (t) through the adjustable delay unit 37. The voltage obtained at the output of the multiplier 34 is passed through a low-pass filter 35, at the output of which a correlation function R (τ) is formed, where τ is the current time delay. The extreme controller 36, designed to maintain the maximum value of the correlation function R (τ) and connected to the output of the low-pass filter 35, acts on the control input of the adjustable delay unit 37 and maintains the delay τ introduced by it equal to τ _З (τ = τ _З ), which corresponds to the maximum value of the correlation function R (τ). The range indicator 38, associated with the scale of the adjustable delay unit 37, allows you to directly read the measured value of the distance R from the ground point to the satellite repeater according to the formula

,

,

where c is the propagation velocity of radio waves.

Therefore, the task of measuring the distance R from a ground station to an artificial satellite repeater is reduced to automatic measurement of the time delay τ _{3 of the} relay signal relative to the interrogation signal.

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.

по часам второго пункта аналогично формируют и регистрируют шумоподобный СВЧ-сигнал (сигнал β₃). Сформированный сигнал преобразуют на частоте ω₁, усиливают его по мощности, излучают усиленный сигнал в направлении того же ИСЗ-ретранслятора.At an arbitrary point in time

by the hours of the second point, a noise-like microwave signal (signal β ₃ ) is similarly generated and recorded. The generated signal is converted at a frequency of ω ₁ , amplified by power, emitted amplified signal in the direction of the same satellite repeater.

по часам первого пункта А с помощью той же кодовой последовательности формируют такой же шумовой СВЧ-сигнал (сигнал α₃), регистрируют его на первом пункте А. Принимают бортовой аппаратурой ИСЗ-ретранслятора сигнал на частоте ω₁ (сигнал α₃), переизлучают его на пункты А и В на частоте ω₂ с сохранением фазовых соотношений, принимают ретранслированный сигнал на обоих пунктах, преобразуют его на видеочастоту, регистрируют в моменты времени

и

соответственно (сигнал α₄, β₄).At that moment in time

by the clock of the first point A using the same code sequence form the same noise microwave signal (signal α ₃ ), register it at the first point A. Receive on-board equipment of the satellite repeater signal at a frequency 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 a video frequency, register at time points

and

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:

,

,

,

,

,

,

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);

,

- задержки сигналов в излучающей аппаратуре обоих пунктов;

,

- signal delays in the radiating equipment of both points;

,

- задержки сигналов в приемно-регистрирующей аппаратуре;

,

- signal delays in receiving and recording equipment;

ΔS - signal delay in the onboard satellite repeater;

- искомая разность показаний часов в один и тот же физический момент.

- the desired difference in the clock at the same physical moment.

,

, получаемAssuming a _j and b _j linear functions with derivatives

,

we get

,

,

,

,

,

,

,

,

,

,

,

- задержки сигнала в атмосфере на частотах ω₂ и ω₂ соответственно;

,

- signal delays in the atmosphere at frequencies ω ₂ and ω _2, respectively;

- релятивистская поправка (эффект Саньяка);

- 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 a false signal (interference)

u _З (t) = U _З сs (ω _З t + ϕ _З ), 0≤t≤T _З ,

is taken through the mirror channel at a frequency of ω _З , then the following voltages are allocated by amplifiers 14 and 20 of the second intermediate frequency:

u _CR5 (t) = U _CR5 cos (ω _CR2 t + ϕ _CR5 ),

u _CR6 (t) = U _CR5 cos (ω _CR2 t + ϕ _CR5 -90 °), 0≤t≤T _З ,

Where

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

ϕ _pr5 = ϕ ₃ -ϕ _G2 .

The voltage u _p6 (t) from the output 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 the following voltage is generated

U _pp7 (t) = U _pp5 cos (ω _p2 t + ϕ _pr5 -90 ° -90 °) = - U _p5 cos (ω _p2 t + ϕ _pr5 ), 0≤t≤T _p .

The _voltages u _pr5 (t) and u _p7 (t) supplied to the two inputs of the adder 22 are compensated at its output.

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

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

If a false signal (interference) is received on the first combination channel at a frequency ω _K1

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

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

u _CR8 (t) = U _CR2 cos (ω _CR2 t + ϕ _CR8 ),

u _CR9 (t) = U _CR8 cos (ω _CR2 t + ϕ _CR8 -90 °), 0≤t≤T _K1 ,

Where

ω _pp8 = 2ω _G2 -ω _K1 ;

with _pr2 = 2 with _{G2 -} with _K1 - the second intermediate (difference) frequency;

ϕ _pr8 = ϕ _G2 -ϕ _K1 .

The voltage u _p9 (t) from the output 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 _pp8 (t) = U _pp8 cos (ω _p2 t + ϕ _p8 + 90 ° -90 °) = - U _p8 cos (ω _p2 t + ϕ _p8 ), 0≤t≤T _p .

Voltages u _pp8 (t) and u _pp10 (t) are supplied to two inputs of the adder 22, the output of which forms the following total voltage

u _∑1 (t) = U _∑1 cos (ω _np2 t + ϕ _pr8 ), 0≤t≤T _K1 ,

where U _∑1 = 2U _pp8 .

This voltage is supplied to the second input of the multiplier 23, at the output of which the following harmonic voltage is formed

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

.Where

.

This voltage does not fall into the passband of the narrow-band filter 24. Therefore, a false signal (interference) received on the first combinational channel at a frequency ω _K1 is suppressed.

The clock synchronization method allows you to:

- achieve extreme measurement accuracy (about ± 0.1 ns) using PC DB 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.

The proposed method provides improved noise immunity and accuracy of synchronization of remote time scales. This is achieved by suppressing false signals (interference) received via mirror and Raman channels.

Moreover, the suppression of false signals (interference) received via the mirror and the second Raman channel is provided by the phase-compensation method, which is implemented by the local oscillator 2.2, mixers 13 and 19, amplifiers 14 and 20 of the second intermediate frequency, phase shifters 18 and 21 by + 90 ° and -90 ° and adder 22.

The suppression of false signals (interference) received via the first combinational channel is provided by the narrow-band filtering method, which is implemented by a multiplier 23, a narrow-band filter 24, an amplitude detector 25, and a key 26.

The proposed method and device provide improved accuracy of synchronization of remote time scales. This is achieved by measuring the distance R from the ground point to the satellite, the speed and direction of its movement in a geostationary orbit relative to the ground point.

Moreover, the measurement of the radial velocity of the satellite repeater is carried out using multiple frequency conversion of the received signal, is characterized by comparative simplicity and does not have restrictions on the number of ground stations that measure the radial speed of the satellite repeater.

The measurement of the distance R from the ground point to the satellite repeater is carried out automatically using the remarkable property of the correlation function R (τ) of noise-like microwave signals, which has a significant main lobe and a relatively low level of side lobes.

Relay signals with phase shift keying (PSK):

,

,

,

,

,

,

from the outputs of amplifiers 12.1, 12.2 and 12.3 of the power of the first A, second B and third C of ground points through the corresponding communication lines 39.1, 39.2 and 39.3, for example optoelectronic, enter the inputs of phase doublers 41.1, 41.2 and 41.3, at the outputs of which harmonic voltages are formed:

u ₃₁ (t) = U ₃₁ cos [2 (ω ₂ ± Ω _Д ) (t-τ _З ) + 2ϕ ₂₁ ],

u ₃₂ (t) = U ₃₂ cos [2 (ω ₂ ± Ω _Д ) (t-τ _З ) + 2ϕ ₂₂ ],

u ₃₃ (t) = U ₃₃ cos [2 (ω ₂ ± Ω _Д ) (t-τ _З ) + 2ϕ ₂₃ ], 0≤t≤T _s .

These voltages arrive at the inputs of the phase dividers into two 42.1, 42.2 and 42.3, respectively, at the outputs of which the following harmonic voltages are formed:

u ₄₁ (t) = U ₄₁ cos [2 (ω ₂ ± Ω _Д ) (t-τ _З ) + 2ϕ ₂₁ ],

u ₄₂ (t) = U ₄₂ cos [2 (ω ₂ ± Ω _Д ) (t-τ _З ) + 2ϕ ₂₂ ],

u ₄₃ (t) = U ₄₃ cos [2 (ω ₂ ± Ω _Д ) (t-τ _З ) + 2ϕ ₂₃ ], 0≤t≤T _s ,

which are allocated by narrow-band filters 43.1, 43.2 and 43.3, respectively, and fed to the inputs of the phase meters 44.1, 44.2 and 44.3.

Phasometers 44.1, 44.2 and 44.3 measure the following phase shifts

;

;

;

;

,

,

where d ₁ , d ₂ , d ₃ - extra-long measuring base (Fig. 1);

λ is the wavelength

which enter the computer 50.

So the phase scales of direction finding of an AES repeater are formed in three planes, accurate but ambiguous.

The voltage u ₂₁ (t) from the output of the communication line 39.1 through the first 49.1 and second 49.2 adjustable delay blocks is supplied to the first inputs of the first 46.1 and second 46.2 multipliers, the second inputs of which are supplied with voltage u ₂₂ (t) and u ₂₃ (t) from the outputs communication lines 39.2 and 39.3 respectively. The voltages obtained at the outputs of multipliers 46.1 and 46.2 are passed through low-pass filters 47.1 and 47.2, at the outputs of which the first R ₁ (τ) and second R ₂ (τ) correlation functions are formed.

Extreme controllers 48.1 and 48.2, designed to maintain the maximum value of the correlation functions R ₁ (τ) and R ₂ (τ) and connected to the outputs of the low-pass filters 47.1 and 47.2, act on the control inputs of the adjustable delay units 49.1 and 49.2 and support the delays they enter equal to τ ₁ and τ ₂ (τ = τ ₁ , τ = τ ₂ ), which corresponds to the maximum values of the correlation functions R ₁ (τ) and R ₂ (τ).

The scales of blocks 49.1 and 49.2 of adjustable delays are calibrated directly in the values of the angular coordinates of the satellite repeater:

,

,

,

,

where c is the propagation velocity of radio waves;

d ₁ , d ₂ - ultra-long measuring base.

The angular coordinates α and β are received at the fourth and fifth inputs of the computer 50.

The voltage u ₂₃ (X) from the output of the communication line 39.3 through the third block 49.3 is supplied to the first input of the third multiplier 46.3, the second input of which from the output of the communication line 39.2 is supplied with the voltage u ₂₂ (t). The voltage obtained at the output of multiplier 46.3 is passed through a low-pass filter 47.3, at the output of which a third R ₃ (τ) correlation function is formed. The extreme controller 48.3, designed to maintain the maximum value of the correlation function R ₃ (τ), acts on the control input of the adjustable delay unit 49.3 and maintains the delay introduced by it equal to τ _З (τ = τ _З ), which corresponds to the maximum value of the correlation function R ₃ (τ ) The scale of the adjustable delay unit 49.3 is calibrated directly in the angular coordinate of the satellite repeater

,

,

where d ₃ is an extra-long measuring base.

The angular coordinate γ arrives at the sixth input of the computer 50.

So the time scales of direction finding of the satellite repeater in three planes are formed, rough, but unambiguous. In computer 50, the exact and unambiguous location of the satellite repeater and its movement in space is determined.

Thus, the proposed method and device in comparison with prototypes and other technical solutions of a similar purpose provide increased accuracy of synchronization of remote time scales. This is achieved by using a third ground station, the formation of ultra-long measuring bases in three planes, which allows you to accurately and unambiguously measure the angular coordinates α, β and γ of the satellite repeater, its location and movement in space. Moreover, the high accuracy of measurement of these coordinates is provided by extra-long measuring bases d ₁ , d ₂ and d ₃ , and the resulting ambiguity is eliminated by correlation processing of received noise-like signals.

The proposed method and device provide accurate and unambiguous measurement of the angular coordinates and the location of various quasars and other celestial bodies in near and far space, especially when using four ground stations and six ultra-long measuring bases. Moreover, in near space, spacecraft, airplanes, helicopters, rockets, etc. can be sources of radio emission.

Claims (20)

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, study 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, the same noise-like microwave signal is generated, recorded at the second point, the signal at the frequency ω _{1 is} received by the onboard equipment of the artificial Earth-relay satellite, and re-emitted to the first and second points at a frequency of ω ₂ preserving the phase relationships, at an arbitrary time t ₃ according to the clock of the second point, a microwave noise signal is generated and recorded in the same way, the generated signal is converted to frequency ω ₁ , amplified by power, emitted amplified signal in the direction of the same artificial Earth-relay satellite, at the same time t ₃ according to the clock of the first point using the same code sequence form the same noise-like microwave signal, register it at the first point, take more with the on-board equipment of the artificial Earth-relay satellite, the signal at the frequency ω ₁ and re-emit it to the first and second points at the frequency ω ₂ with preserving the phase relations, the received signal at the frequency ω _{2 is} converted in frequency using the voltage of the second local oscillator, phase shifted by +90 °, the voltage of the second intermediate frequency is isolated, it is shifted in phase by -90 °, summed with the initial voltage of the second intermediate frequency, the resulting total voltage is multiplied with the received signal, the harmonic is isolated the second voltage at the frequency ω _{G2 of the} second local oscillator, it is detected and used to resolve further processing of the received signal, the resulting total voltage is converted in frequency using the voltage of the first reference frequency ω _E1 , the voltage of the third intermediate frequency is isolated

convert it in frequency using the voltage of the second reference frequency

where Ω ₀ is the frequency of the stand, which is introduced to determine the sign of the Doppler shift Ω _D , emit a low frequency voltage ω _n = Ω _D + Ω ₀ , measure the low frequency ω _N and depending on whether ω _N > Ω ₀ or ω _N <Ω ₀ determine the sign of the Doppler shift, and therefore the direction of the radial velocity of the satellite repeater, simultaneously obtained total voltage multiplied with the noise-like microwave signal passed through a delay-controlled unit, allocate a low-frequency voltage proportional to the correlation function R (τ), where τ - current time delay, changing a time delay τ equal to yield τ = τ _W, Th It corresponds to the maximum value of the correlation function R (τ), and determining its supporting distance from ground station to satellite repeater by the formula

, where c is the propagation velocity of radio waves, characterized in that they use a third ground station and an information processing center, and three ground stations are placed in the form of a geometric triangle, at the tops of which land stations are placed, and the sides form ultra-long measuring bases, signals received at ground stations are transmitted via communication lines, for example fiber-optic, harmonic oscillations are emitted into the information processing center, in which three processing channels are formed, in each of which phase-shift keying in the received noise-like signals is eliminated measurements, the phase differences between them are formed, forming phase scales of the direction finding of the satellite repeater, accurate but ambiguous, at the same time the signal of the second processing channel is multiplied by the signal of the first processing channel passed through the first block of adjustable delay, a low-frequency voltage proportional to the first correlation function R ₁ ( τ), where τ is the current time delay, the time delay τ is changed until the equality τ = τ _{1 is} obtained, which corresponds to the maximum value of the first correlation function R ₁ (τ), it and determine the first angle α on the satellite repeater according to the formula

where c is the propagation velocity of radio waves; d ₁ - the distance between ground points A and B (extra-long measuring base), the signal of the third processing channel is multiplied with the signal of the first processing channel passed through the second adjustable delay unit, a low-frequency voltage proportional to the second correlation function R ₂ (τ) is extracted, the time delay τ is changed until the equality τ = τ _{2 is} obtained, which corresponds to the maximum value of the second correlation functions R ₂ (τ), support it and determine the second angle on the satellite repeater according to the formula

where d ₂ is the distance between ground points A and C (extra-long measuring base), the signal of the second processing channel is multiplied with the signal of the third processing channel, passed through the third adjustable delay unit, a low-frequency voltage proportional to the third correlation function R ₃ (t) is extracted, the time delay τ is changed until the equality τ = τ _{3 is} obtained, which corresponds to the maximum value of the third correlation functions R ₃ (t), support it and determine the third angle of the satellite repeater according to the formula

, where d ₃ - the distance between ground points B and C (extra-long measuring base), forming the time scales of direction finding of the satellite repeater, rough, but unambiguous. 2. A device for clock synchronization, 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, an amplifier the first intermediate frequency, the first power amplifier, a duplexer, the input-output of which is connected to the transceiver antenna, the second power amplifier, the second mixer, the second input of which through the second local oscillator connected to the first output of the frequency and time standard, the first amplifier of the second intermediate frequency, the adder, the first multiplier, the second input of which is connected to the output of the second power amplifier, a narrow-band filter, an amplitude detector, a key, the second input of which is connected to the output of the adder, the second a clipper, the second input of which is connected to the second output of the frequency and time standard, a second buffer storage device and a meter of delays and their derivatives, the output of which is the output of the ground functions connected in series to the third output of the frequency and time standard, a 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 is connected to the second input of the delay meter and their derivatives, connected in series 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 is a second intermediate frequency and the second phase shifter at -90 °, the output of which is connected to the second input of the adder, the fourth mixer is connected in series to the key output, the second input of which is connected to the first output of the reference frequency unit, the amplifier of the third intermediate frequency, the fifth mixer, the second input of which is connected to the second output of the block of reference frequencies, the first low-pass filter and a Doppler frequency meter, a second multiplier, a second low-pass filter, an extremal regulator and bl ok adjustable delay, the second input of which is connected to the output of the pseudo-random signal generator, the first output is connected to the second input of the second multiplier, and the second output is connected to the range indicator, characterized in that it is equipped with a third point and an information processing center, and three ground points are located in in the form of a geometric triangle, at the tops of which ground points are placed, and the sides form ultra-long measuring bases, the information processing center is made in the form of three processing channels information connected to the outputs of the second power amplifiers of three ground points through the corresponding delay lines, with each information processing channel consisting of a phase divider, a phase divider into two and a narrow-band filter connected in series to the communication lines, the outputs of the narrow-band filters of the first and second processing channels through the first the phase meter is connected to the first input of the computer, the outputs of the narrow-band filters of the first and second processing channels through the second phase meter are connected to the second input of the computer, The narrow-band filters of the second and third processing channels are connected through the third phase meter to the third input of the computer, the first adjustable delay unit, the first multiplier, the second input of which is connected to the output of the communication line of the second ground point, the first low-pass filter, are connected in series to the output of the communication line of the first ground station and the first extreme controller, the output of which is connected to the second input of the first block of adjustable delay, the second output of which is connected to the fourth input of the computer, to the second control unit, the second multiplier, the second input of which is connected to the output of the communication line of the third ground station, the second low-pass filter and the second extreme regulator, the output of which is connected to the second input of the second adjustable delay unit, the second output which is connected to the fifth input of the computer, the third block of adjustable delay, the third multiplier, the second second input of which is connected to the output link of the second ground station, the third lowpass filter and a third extreme regulator whose output is connected to a second input of the third variable delay unit, a second output is connected to the sixth input of the computer.

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