RU2165627C1 - Doppler phase-meter of multifrequency signals - Google Patents

Abstract

FIELD: measurement technology, measurement of radial velocity of object in multifrequency radars of simultaneous radiation, radiolocation and navigation systems for unambiguous determination of Doppler velocity. SUBSTANCE: Doppler phase-meter of multifrequency signals has two frequency channels which process initial readings on basis of units of delay, complex ganging, complex multiplication, averaging and modulus computation, circuit computing evaluation of Doppler velocity on basis of units computing phase, correction of measurement limits connected in series and of additional multiplier and two circuits of integration of frequency channels on basis of additional adder and additional complex multiplier together with unit of complex ganging whose usage makes it feasible to raise detection efficiency and to ensure required range of unambiguously measured Doppler velocities which is technical result of invention. EFFECT: raised detection efficiency and ensured range of unambiguously measured Doppler velocities. 10 dwg

Description

 The invention relates to measuring technique and is intended for measuring the difference of Doppler phase incursions (radial velocity of an object) of multi-frequency radio-pulse periodic signals against a background of noise; can be used in radar and navigation systems to uniquely determine the Doppler speed.

Known phase meter of the average phase incursion value [1], containing series-connected instantaneous phase meter, memory unit, subtraction unit, the second input of which is connected to the output of the instantaneous phase meter, convolution unit, trigonometric converter, two outputs of which are connected to two identical channels consisting of connected in series multiplier and averaging unit, the outputs of the averaging unit of each channel are connected to the corresponding inputs of the phase calculation unit, the second inputs of the multiplier h Through the module calculation unit, they are connected to the input of the instantaneous phase meter, which is the input of the device. However, this device, due to the double trigonometric transformation, has a large hardware error and has small measurement limits for the phase [-π / 2; π / 2].
Also known is a phase meter [2], which contains two adders, the inputs of which are the inputs of the phase meter, envelope detectors are also connected to them, the outputs of the adders are connected through series-connected amplifiers with AGCs, delay lines and keys with the second inputs of the adders, the second inputs of the keys are connected to the outputs of the detectors envelopes, and the second inputs of the amplifiers with AGC are connected to the outputs of the reference voltage source, the outputs of the adders are connected to the inputs of the mixers, the outputs of which are through series-connected low-pass filters and selective amplifiers are connected to the inputs of the phase indicator, the output of one of the low-pass filters is connected to the input of the PLL system, the outputs of which are connected to the second inputs of the mixers. However, this device has low measurement accuracy and, in addition, due to the presence of a PLL in it, it has increased inertia.

 Closest to the invention is a phase meter of the Doppler phase advance of radio pulse signals [3], selected as a prototype, containing a delay unit, the outputs of which are connected to the inputs of the complex conjugation unit (based on an inverter), the outputs of which are connected to the second inputs of the complex multiplication block, the first inputs which are combined with the inputs of the delay unit, which are the inputs of the phase meter, the outputs of the complex multiplication unit are connected to the inputs of the averaging unit, the outputs of which are connected to the inputs of the unit the numbers of the module and the inputs of the phase calculation unit, as well as with the second inputs of the measurement range correction unit, the first input of which is connected to the output of the phase calculation unit; the output of the block for correction of the limits of measurement is connected to the input of the key, the control input of which is connected through the threshold block to the output of the unit for calculating the module, the second input of the threshold block is connected to the output of the memory block. However, this device has a low detection efficiency and a limited measurement range of Doppler (radial) speed.

 The problem solved in the invention is to increase the detection efficiency and expand the range of uniquely measured radial velocities.

 To solve the problem, a Doppler phase meter of multi-frequency signals containing the I-th channel, a memory block, a threshold block, a phase calculation block, a block for correcting the measurement limits, a key and a clock generator, the I-th channel consists of a delay block, a complex pairing block, a block complex multiplication, averaging unit and module calculation unit, the 2nd channel, an additional complex conjugation unit, an additional complex multiplication unit, an additional multiplication unit, an additional memory block are introduced , an additional adder, and the 2nd channel consists of a delay block, a complex conjugation block, a complex multiplication block, an averaging block, and a module calculation block.

 Additional blocks introduced into the proposed device are known. Thus, the delay unit, the complex conjugation unit, the complex multiplication unit, the averaging unit, and the module calculation unit that make up the I (II) channel, connected together with the threshold block form an invariant system for processing radio signals and are used to detect them, but it is not known combined use of the 1st and 2nd channels, combined by an additional adder. New are the links between the block of additional complex multiplication and the block of additional complex conjugation, the connection between the block of averaging of the 1st channel and the block of additional complex multiplication, the connection between the block of additional complex conjugation and the block of averaging of the 2nd channel, the connection between the block of additional complex multiplication and blocks calculation of the phase and correction of the limits of measurement, as well as the relationship between the additional unit of multiplication and the block of correction of the limits of measurement, which provides ix detection efficiency and range extension unambiguously measured radial velocity. Communications between the clock and all blocks of the Doppler phase meter of multi-frequency signals provide consistent processing of the multi-frequency sequence of radio pulses.

 Comparison with the technical characteristics known from published sources of information shows that the claimed solution has novelty and has an inventive step.

 The claimed solution is technical in nature, feasible, reproducible and, therefore, is industrially applicable.

 In FIG. 1 is a structural electrical diagram of a Doppler phase meter of multi-frequency signals; in FIG. 2 - delay unit; in FIG. 3 - block complex conjugation; in FIG. 4 - block complex multiplication; in FIG. 5 - averaging unit; in FIG. 6 - module calculation unit; in FIG. 7 - phase calculation unit; in FIG. 8 - block correction of measurement limits; in FIG. 9 - block assignment of a sign; in FIG. 10 shows the detection characteristics of the prototype and the proposed device.

 The Doppler phase meter of multi-frequency signals contains two channels (I-I, II-I), each of which includes a delay unit 1, complex conjugation unit 2, complex multiplication unit 3, averaging unit 4 and module calculation unit 5, while the outputs of delay unit 1 connected to the inputs of the complex conjugation unit 2, the outputs of which are connected to the first inputs of the complex multiplication unit 3, the outputs of which are connected to the inputs of the averaging unit 4, the outputs of which are connected to the inputs of the module calculation unit 5, the inputs of the I (II) channel are The interconnected inputs of the delay unit 1 and the second inputs of the complex multiplication unit 3 are interconnected, and the first and second outputs of the I (II) channel are respectively the outputs of the averaging unit 4 and the output of the module calculation unit 5, phase calculation unit 6, block 7 correction of measurement limits, key 8, threshold block 9, memory block 10, clock generator 11, additional complex conjugation unit 12, additional complex multiplication unit 13, additional multiplication unit 14, additional memory unit 15, additional adder 16.

 The output of the phase calculation unit 6 is connected to the first input of the measurement limits correction unit 7, the control input of the key 8 is connected to the output of the threshold unit 9, the first input of which is connected to the output of the memory unit 10, the first outputs of the second channel are connected to the inputs of the additional complex interface unit 12 the outputs of which are connected to the first inputs of the additional complex multiplication block 13, the second inputs of which are connected to the first outputs of the 1st channel, the outputs of the additional complex multiplication block 13 are connected to the same the inputs of the phase calculation unit 6 and the second inputs of the measurement limits correction unit 7, the output of which is connected to the first input of the additional multiplication unit 14, the second input of which is connected to the output of the additional memory unit 15, the output of the additional multiplication unit 14 is connected to the key 8 input, the second outputs I of the second and second channels are connected to the inputs of the additional adder 16, the output of which is connected to the second input of the threshold unit 9, the output of the clock generator 11 is connected to the clock inputs of all blocks of the Doppler phase meter multipart signals, the first and second inputs of which are the inputs of the 1st and 2nd channels, respectively, and the first and second outputs are the outputs of the key 8 and threshold block 9, respectively.

 Blocks 1 delay (I-th (II-th) channel) contain two delay lines 17 for the interval T, the inputs of the delay blocks are the inputs of the delay line 17, the outputs of which are the outputs of the delay blocks.

 Block 2 complex conjugation (I-th (II-th) channel) and an additional block 12 complex conjugation comprise an inverter 18, the first input of the complex conjugation block is its first output, the second input is the input of the inverter 18, the output of which is the second output of the complex conjugation block .

 Block 3 complex multiplication (I-th (II-th) channel) and an additional block 13 complex multiplication contain two channels (I, II), each of which includes the first multiplier 19, the second multiplier 20 and the adder 21 connected in series, the output of the first multiplier 19 of one channel is connected to the second input of the adder 21 of the other channel, and the first and second inputs of the complex multiplication block, respectively, are the first inputs of the first and second multipliers 19, 20 of each channel, the combined second inputs of the second second multipliers 20 and the combined second inputs of the first multipliers 19, and the outputs of the complex multiplication block are the outputs of the adders 21 channels.

 Block 4 averaging of the I (II) channel contains two channels (I, II), each of which consists of N-1 series-connected delay lines 22 to the interval T and N-1 of adders 23, the inputs of the averaging block are the combined inputs the first delay line 22 and the first adder 23 of each channel (I, II), and the output of the Kth (K = 2, (M-1)) delay line 22 is connected to the second input of the Kth (K = 2, (N- 1)) of the adder 23 of each channel (I, II), the outputs of the averaging block are the outputs of the (N-1) -th adder.

 Block 5 of the calculation module of the I-th (II-th) channel contains two blocks 24 multiplication and an adder 25, the inputs of the block calculation module are the inputs of the blocks 24 multiplication, the outputs of which are connected to the first and second inputs of the adder 25, the output of which is the output of the module calculation unit .

 The phase calculation unit 6 comprises a series-connected divider 26 and a functional converter 27, the inputs of the phase calculation block are the inputs of the divider 26, and the outputs of the phase calculation block are the outputs of the functional converter 27.

 Block 7 correction of measurement limits contains sequentially connected modular block 28, adder 29, block 30 of the assignment of the character, the first key 31, adder 32, while the first input of the block correction of the limits of measurement through the second key 33 is connected to the second input of the adder 32, the output of the memory unit 34 connected to the second input of the adder 29, the third input of the block for correcting the limits of measurement is connected to the control inputs of the first 31 and second 33 keys, the first input of the block 30 character is the second input of the block for correcting the limits of measurement, the output is the sum torus 32 is its output.

 The character assigning unit 30 comprises multiplication units 35, 38, a memory unit 36, a limiter 37, the first input of the character assigning unit being the first input of the multiplying unit 35, the second input of which is connected to the output of the memory unit 36, the output of the multiplying unit 35 is connected to the input of the limiter 37 whose output is connected to the first input of the multiplication unit 38, the second input of which is the second input of the character assignment unit, the output of the character assignment unit is the output of the multiplication unit 38.

 The Doppler phase meter of multi-frequency signals operates as follows.

где U_j ^(k) - j-й отсчет последовательности комплексных величин в k-м частотном канале;
x_j ^(k) и y_j ^(k) - соответственно действительная и мнимая части комплексного отсчета;
k - номер частотного канала, причем k = 1, 2;
φ $\genfrac{}{}{0ex}{}{\text{(}}{\text{0}}$ ^k) - начальная фаза в k-м частотном канале;
φ^(k) - доплеровские сдвиги фаз сигнала за период повторения T в k-м частотном канале, равный

где F $\genfrac{}{}{0ex}{}{\text{(}}{\text{∂}}$ ^k) - доплеровская частота в k-м канале;
T - период повторения импульсов;
f_н ^(k) - k-я несущая частота, причем f_н ⁽¹⁾ больше f_н ⁽²⁾;
v_r -радиальная скорость цели.A multi-frequency signal, consisting of two frequency components, is fed to the input of each frequency channel of the receiver, where amplification stages are successively converted into a video frequency in quadrature phase detectors and, through analog-to-digital converters (the listed blocks in Fig. 1 are not shown), are fed to the inputs of the claimed devices. In this case, the quadrature components of the signal in each frequency channel are described in a single range resolution element by a sequence of complex quantities

where U _j ^(k) is the jth sample of the sequence of complex quantities in the kth frequency channel;
x _j ^(k) and y _j ^(k) are the real and imaginary parts of the complex reference, respectively;
k is the number of the frequency channel, and k = 1, 2;
φ $\genfrac{}{}{0ex}{}{\text{(}}{\text{0}}$ ^k) is the initial phase in the k-th frequency channel;
φ ^(k) - Doppler phase shifts of the signal during the repetition period T in the k-th frequency channel, equal to

where f $\genfrac{}{}{0ex}{}{\text{(}}{\text{∂}}$ ^k) is the Doppler frequency in the kth channel;
T is the pulse repetition period;
f _n ^(k) is the k-th carrier frequency, and f _n ^{(1) is} greater than f _n ⁽²⁾ ;
v _{r is the} radial velocity of the target.

С выхода блоков 3 комплексного умножения отсчеты поступают в блоки 4 усреднения (фиг. 5), осуществляющие с помощью элементов 22 задержки и сумматоров 23 скользящее вдоль азимута суммирование, что приводит к образованию на выходах блоков 3 усреднения величин

С первых выходов I-го и II-го каналов (фиг. 1) отсчеты поступают соответственно на второй вход дополнительного блока 13 комплексного умножения и через дополнительный блок 12 комплексного сопряжения на первый вход дополнительного блока 13 комплексного умножения, где осуществляется обработка отсчетов в соответствии с алгоритмом, аналогичным выражению (3), что приводит к образованию на его выходе величины
X = a+ib = X⁽¹⁾X^(2)* = |X⁽¹⁾||X⁽²⁾|exp(iΔφ), (5)
где Δφ = φ⁽¹⁾-φ⁽²⁾ - разность доплеровских сдвигов фаз сигнала между двумя частотными каналами.The samples U _j ⁽¹⁾ and U _j ⁽²⁾ are respectively received at the inputs of the 1st and 2nd channels (Fig. 1), where in blocks 1 the delays (Fig. 2) are delayed by the repetition period T. After that, in the block 2 complex conjugation (Fig. 3) is a complex conjugation of the delayed reference. Next, in block 3 of complex multiplication (Fig. 4), the processing of samples is carried out in accordance with the algorithm

From the output of the complex multiplication blocks 3, the samples arrive at the averaging blocks 4 (Fig. 5), which, using the delay elements 22 and the adders 23, carry out summing along the azimuth, which leads to the formation of averaging values at the outputs of the blocks 3

From the first outputs of the first and second channels (Fig. 1), the samples are respectively sent to the second input of the additional complex multiplication block 13 and, through the additional complex conjugation block 12, to the first input of the additional complex multiplication block 13, where the samples are processed in accordance with an algorithm similar to expression (3), which leads to the formation at its output of a quantity
X = a + ib = X ⁽¹⁾ X ^{(2) *} = | X ⁽¹⁾ || X ⁽²⁾ | exp (iΔφ), (5)
where Δφ = φ ⁽¹⁾ -φ ⁽²⁾ is the difference of the Doppler phase shifts of the signal between two frequency channels.

вычитаемый в блоке 29 из величины π, поступающей от блока 34 памяти. Полученной разности в блоке 30 присваивается знак величины b.Values a and b are supplied to the corresponding inputs of the phase calculation unit 6 (Fig. 7), where the estimate Δφ = arctg (b / a) is calculated. Subsequent conversions of Δφ occur in block 7 correction limits of measurement (Fig. 8) and depend on the sign of a. When a ≥ 0, the second key 33 is open, and the value through the adder 32 directly goes to the output of the correction unit of the measurement limits. When a <0, the first key 31 is open, and the second key 33 is closed. Thus in the modular block 28 is formed

subtracted in block 29 from the value of π coming from the block 34 of the memory. The resulting difference in block 30 is assigned the sign of b.

 Block 30 character assignment (Fig. 9) works as follows. The value b (ratio (5), where it is multiplied by a constant factor from the memory unit 36 for the purpose of scaling and further restriction in the limiter 37 by the level of ± 1, is supplied to the first input of the sign assignment unit. Thus, after the limitation, the value at the output of the limiter 37 it makes sense to sign the quantity b, which, entering the first input of the multiplication unit 38, is assigned the difference π- | Δφ | supplied to the second input of the sign assignment unit, that is, to the second input of the multiplication unit 38 from the output of the adder 29.

Дополнительный блок 14 умножения (фиг. 1) осуществляет умножение найденной оценки разности фаз на коэффициент d, хранящейся в дополнительном блоке 15 памяти, что позволяет найти однозначную оценку радиальной скорости в соответствии с алгоритмом

Таким образом, соответствующим выбором разноса несущих частот обеспечивается необходимый диапазон однозначно измеряемых доплеровских скоростей, который расширяется по сравнению с одночастотным сигналом в f_н/(f_н ⁽¹⁾ - f_н ⁽²⁾) раз. При этом сохраняется однозначность измерения дальности, которая обеспечивается соответствующим выбором периода повторения импульсов T.The operations considered make it possible to find in phase calculation block 6 an estimate of the phase difference that is within [-π / 2, π / 2], and then expand the limits of its unambiguous measurement [-π, π] in block 7 of the measurement limits correction, in accordance with an algorithm

The additional block 14 multiplication (Fig. 1) multiplies the found estimates of the phase difference by the coefficient d stored in the additional block 15 of the memory, which allows you to find a unique estimate of the radial velocity in accordance with the algorithm

Thus, by the appropriate choice of the carrier frequency spacing, the necessary range of unambiguously measured Doppler velocities is provided, which expands in comparison with a single-frequency signal by f _n / (f _n ⁽¹⁾ - f _n ⁽²⁾ ) times. This preserves the uniqueness of the range measurement, which is ensured by the appropriate choice of the pulse repetition period T.

To reduce the likelihood of the device working by noise, it excludes the issuance of the obtained estimate for output in the absence of a signal reflected from the target. From the outputs of the averaging blocks 4 of the 1st and 2nd channels (Fig. 1), the quantities a ^(k) and b ^(k) (relation (4)) are fed to the inputs of the calculation blocks 5 (Fig. 6) of the 1st and II channel, where the processing of samples in accordance with the algorithm
z ^(K) = | X ^(k) | ² = (a ^(k) ) ² + (b ^(k) ) ² . (8)
Next, the samples z ^(k) from the outputs of blocks 5 for calculating the module of the first and second channels are fed to the inputs of an additional adder 16, the output of which is equal to
z = z ⁽¹⁾ + z ⁽²⁾ ≥ z ₀ ,
arrives at the second input of the threshold unit 9. If an excess occurs over the threshold value z ₀ recorded in the memory unit 10, then the output of the threshold unit 9 receives a signal allowing the calculation result to pass from the output of the additional multiplication unit 14 via key 8 to the first output of the multi-frequency Doppler phase meter signals. Otherwise, key 15 is open. In addition, the output of the threshold unit 9, which is the second output of the Doppler phase meter of multi-frequency signals, can be used to read other coordinates, such as range.

Synchronization of the Doppler phase meter of multi-frequency signals is carried out by applying to all blocks of the claimed device a sequence of synchronizing pulses generated by the synchro-generator 11 (Fig. 1), with a repetition period t _k determined from the conditions for ensuring the required resolution in range.

In FIG. 10 shows the dependences of the detection characteristics D of the proposed device (curve 1) and the prototype (curve 2) on the signal-to-noise ratio at the input of the device. The characteristics are obtained by the method of statistical computer simulation under the condition of equal powers of single-frequency and multi-frequency signals, i.e., q ⁽¹⁾ = q ⁽²⁾ = q / 2, where q is the signal-to-noise ratio for a single-frequency signal. Comparison of the detection characteristics D was carried out for the case of the exponential function of signal correlation, the probability of false alarm F = 10 ^-3 , the number of pulses in the packet N = 20. As can be seen, the proposed device at a level of 0.9 outperforms the prototype 2 dB.

 Thus, the Doppler phase meter of multi-frequency signals allows to increase the detection efficiency without increasing the signal energy and to obtain the required range of unambiguously measured Doppler speeds while maintaining an unambiguous range measurement.

Bibliography
1. A. S. N 737860 (USSR), MKI G 01 R 25/00. Phase meter of the mean phase incursion. / E.V. Arbenin, A.V. Kasatkin and V.A. Ostrozhinsky. Publ. 05/30/1980. - Inventions. - 1980. - N 20.- 226 s.

 2. A.S. N 1195279 (USSR), MKI G 01 R 25/00. Radio pulse phase meter. / V. Ya. Sunyan and E.E. Pashkovsky. Publ. 11/30/1985. - Inventions. - 1985. N 44. - 204 p.

 3. A.S. N 1748086 (USSR), MKI G 01 R 25/00. Phase meter of the Doppler phase advance of radio pulse signals. / D.I. Popov, S.V. Gerasimov and E.N. Mataev. Publ. 07/15/92. - Inventions. - 1992. N 26. -6 p.

Claims (1)

 A Doppler phase meter of multi-frequency signals containing the 1st channel, a phase calculation unit, a measurement limit correction unit, a memory unit, a threshold unit, a key and a clock generator, the 1st channel comprising a delay unit, a complex conjugation unit, a complex multiplication unit, an averaging unit and a module calculation unit, while the outputs of the delay unit are connected to the inputs of the complex conjugation unit, the outputs of which are connected to the first inputs of the complex multiplication unit, the outputs of which are connected to the inputs of the averaging unit, the odes of which are connected to the inputs of the module calculation unit, the inputs of the I-th channel are interconnected inputs of the delay unit and the second inputs of the complex multiplication unit, and the first and second outputs of the I-channel are the outputs of the averaging unit and the output of the module calculation unit, output the phase calculation unit is connected to the first input of the measurement range correction unit, the control input of the key is connected to the output of the threshold unit, the first input of which is connected to the output of the memory unit, the output of the clock it is one with the sync inputs of the delay block of the I-th channel, the complex conjugation block of the I-th channel, the complex multiplication block of the I-th channel, the averaging block of the I-th channel, the calculation block of the I-th channel module, the memory block, the threshold block, the phase calculation block , a unit for correction of the limits of measurement and a key, characterized in that the second channel is additionally introduced, an additional complex conjugation block, an additional complex multiplication block, an additional multiplication block, an additional memory block, an additional adder, and the second channel consists of a delay block, a complex conjugation block, a complex multiplication block, an averaging block, and a module calculation block, while the outputs of the delay block are connected to the inputs of the complex conjugation block, the outputs of which are connected to the first inputs of the complex multiplication block, the outputs of which are connected to the inputs of the averaging block, the outputs of which are connected to the inputs of the module calculation unit, the inputs of the second channel are interconnected inputs of the delay unit of the same name and the second inputs of the complex multiplication block, and the first and second outputs of the second channel are respectively the outputs of the averaging block and the output of the module calculation unit, the second outputs of the I and II channels are connected to the inputs of the additional adder block, the output of which is connected to the second input of the threshold block, the first outputs of I- of the first channel are connected to the second inputs of the additional unit of complex multiplication, the first inputs of which are connected to the outputs of the additional unit of complex conjugation, the inputs of which are connected to the first outputs of the second channel, the outputs of the additional unit the complex multiplication windows are connected to the inputs of the phase calculation unit and the second and third inputs of the measurement limits correction unit, the output of the measurement limits correction unit is connected to the first input of the additional multiplication unit, the second input of which is connected to the output of the additional memory unit, the output of the additional multiplication unit is connected to the input the key, the output of the sync generator is connected to the sync inputs of the delay unit of the II channel, the complex conjugation unit of the II channel, the complex multiplication block of the II channel, the averaging block of the second channel, the calculation block of the module of the second channel, an additional complex conjugation block, an additional complex multiplication block, an additional multiplication block, an additional memory block, an additional adder, the first and second inputs of the Doppler phase meter of multi-frequency signals are respectively inputs I- of the second and second channels, and the first and second outputs are the outputs of the key and threshold block, respectively.

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