RU2239845C2 - Method and system for radar measurement of speeds and co-ordinates of objects (modifications) - Google Patents

Abstract

FIELD: radio electronics, in particular, short-range radio electronics, applicable in collision avoidance and motion monitoring systems.

SUBSTANCE: the method consists in radiation of a continuous frequency modulated sounding signal reception of the reflected signal in one or several space positions, multiplication of the received and radiated signals and computation of the functions of correlation of the obtained homodyne and reference signals, formed their harmonics of the modulating signal. The speeds of the objects are computed according to the frequencies and phases of periodic and component functions of correlation and secondary ones computed functions from them, range-either according to the characteristic of the homodyne signal, or according to the number of the reference signal in the time set, and the angular co-ordinated - according to the difference of the phases of the reflected signals and signals received in different positions. The system has an antenna feed system, homodyne transceiver device, correlometer conditioning the reference signals and computing the correlation functions and the secondary functions, and a processor conditioning the modulating signal and computing the speeds and the co-ordinates of objects.

EFFECT: provided the maximum range, resolving power and accuracy of measurements and co-ordinates of objects at the minimum cost sufficient for the purpose of safety of traffic.

21 cl, 10 dwg

Description

The proposed system relates to the field of electronics, in particular short-range radar, and can be used in systems for preventing collisions of vehicles and traffic control.

In the last decade, there has been a rapid development of radar means for determining the situation on highways, the main advantage of which is the ability to provide drivers of vehicles and employees of traffic control authorities with objective data on the speeds and coordinates of objects on highways at any time and in any weather conditions . Currently, in developed countries, buses and freight vehicles are equipped with similar systems operating in the millimeter wavelength range, and it is expected that by 2005 more than 1 million systems will be installed in passenger cars. A restraining factor for the widespread use of automotive radars (radars) is their relatively high cost (see Microwave Journal, 2001, vol. 44, # 5, p. 271).

Analysis of patent and scientific and technical information allows us to conclude that the main reason for the high cost of systems of this class is the complexity of the analog radar transceiver, which usually contains a large number of expensive microwave nodes.

Most known technical solutions use a linear frequency modulation signal (or a combination of it with a continuous unmodulated signal) for sensing, and information about the speed and range of objects is obtained by measuring the instantaneous frequency difference of the emitted and received signal.

An example of such a solution is the radar and the method of measuring object parameters that it implements, in which relatively high technical parameters are provided by using a complex scheme for generating a sounding signal in a transmitter and double frequency conversion in a receiver (see Millimeter-Wave Radar Sensor for Automotive Intelligent Cruise Control (ICC) , IEEE Transactions on Microwave Theory and Techniques, vol. 45, No. 12, December 1997).

Another example is a method for determining the distance in Doppler velocity vector meters for aircraft (see RF patent No. 20188864 dated 10.07.92), which uses the frequency modulation of the probing signal according to a step-sawtooth law with a given value of the frequency jump per step and the duration of the step with the ability to measure the phase in it. The range is determined by the phase difference of the frequency-modulated emitted and reflected signal at the modulation frequency. A disadvantage of the known measurement method is the low sensitivity due to the fact that the converted received signal (intermediate frequency signal) lies in the low frequency region where there is a high level of flicker noise.

A common drawback of the linear frequency modulation radar method (LFM method) is, as you know, the limitation of the resolution and accuracy of measuring the range by the duration of the frequency modulation period, due to the fact that the received signal is analyzed in the time domain.

The prerequisites for an alternative method of radar using signal processing in the frequency domain (spectral approach) are reflected in the monograph (see Muhammad Abd Al-Wahib Ismail. Radar Altimeter with Dual Frequency Modulation. Foreign Literature Publishing House, M., 1957, (trans. Eng.) or Mohamed Abd-El Wahab Ismael, A Study of the Double Modulated FM Radar, Verlag Leeman, Zurich, 1955). Some of the results presented in Section 2 of the first chapter of the monograph, in particular, the expression (29) obtained by the author for the spectrum of the output signal of the mixer multiplying the emitted and received frequency-modulated harmonic-law signals, are a distant analogue of the proposed radar method. However, in the derivation of formula (29), the author of the monograph made simplifications that hid some features of the spectrum, in particular, the dependence of the phases of the harmonics of the modulating signal on the distance to the reflecting object.

Close to the invention is a method of measuring the parameters of objects, implemented by a homodyne continuous-wave radar with frequency modulation, in which a frequency-modulated microwave oscillator serves both as a transmitter generator and a receiver local oscillator, followed by processing of the mixer signal.

The prototype method of the present invention is a method of radar measuring the speed and coordinates of objects, including the radiation of a periodically modulated frequency probe signal, receiving signals reflected from objects, multiplying the emitted and received signals, amplifying the frequency band obtained as a result of multiplying the homodyne signal and analyzing the received signal intermediate frequencies. The distance to the object is calculated from the measured harmonic amplitude of the spectrum of the output (homodyne) signal of the mixer, and the speed is calculated from the Doppler frequency of changes in this amplitude (see “Radar Reference”, in four volumes edited by M. Skolnik (hereinafter “Reference”), volume 3, M.: Soviet Radio, 1976-1979 (translated from English “RADAR HANDBOOK”, Editor-In-Chief MISkolnik, McGRAU-HILL BOOK COMPANY, 1970) ”, Volume 3, 1979, pp. 258-262) . The disadvantages of this method is the low limit range due to the non-optimal reception of the reflected signals, a large error in measuring the range of objects, due to the strong dependence of the harmonic amplitude on destabilizing factors, as well as the inability to determine the sign of the radial velocity.

According to the greatest number of essential features, the prototype system of the present invention is an automobile radar system (see US patent No. 5325097 dated June 28, 1994, “Multimode Radar for Road Vehicle Blind-zone Target Discrimination”). The known system for radar measurement of the velocities and coordinates of objects includes an antenna-feeder device connected by microwave inputs and outputs, providing radiation from the probe and receiving signals reflected from the measured objects, and a transceiver device that provides the formation of a sounding signal, multiplying the received signals with it and amplifying the intermediate frequencies of the received homodyne signal, as well as an analog-to-digital converter and processor, frequency control input of the probing system the signals and outputs of the intermediate frequency of the transceiver are connected respectively to the analog output of the processor and the inputs of the analog-to-digital converter, and the processor is endowed with programs for controlling the frequency of the transceiver and calculating the speeds and coordinates of objects. The transceiver includes a probe signal generator, the frequency control input of which is connected through a modulator to a digital processor, a mixer, the first input of which is connected to the output of the probe signal generator, the second input is connected to the input of the transceiver device, and the output through a strip amplifier is connected to the output of the transceiver device. Antenna-feeder device is made in the form of transmitting and receiving antennas.

The method implemented by the prototype system for determining vehicle parameters uses a linear frequency-modulated signal with a linearly increasing and linearly decreasing frequency, as well as a mode with a constant frequency of the emitted signal. The emitted and received signals are multiplied, an intermediate frequency signal is extracted, which is converted to digital form and analyzed in the time domain using a digital processor, taking into account the vehicle’s own speed.

The disadvantage of the prototype system is the insufficient limit range and accuracy of measurements due to the above described features of the LFM method, as well as the strong influence of flicker noise.

To eliminate the above drawbacks, the task was to create a method and system for radar measuring the speed and coordinates of objects, providing at a minimum cost sufficient range for road safety purposes, the resolution, resolution and accuracy of measuring speeds and coordinates of objects.

The specified technical result is achieved by the fact that in the method of radar measurement of the speeds and coordinates of objects, including the radiation of a periodically modulated frequency probe signal, the reception of signals reflected from objects, multiplication of the emitted and received signals, amplification in a given frequency band obtained as a result of multiplication of the homodyne signal and analysis the received signal of intermediate frequencies, according to the invention form the main and quadrature frequency sets of reference signals, each of which contains one of the harmonics of the modulating signal, the main and quadrature frequency sets of the correlation functions of the reference signals and the intermediate frequency signal are calculated, from which the many amplitude functions of the harmonics of the intermediate frequency signal are calculated, from the obtained amplitude functions of at least two - even and odd - harmonics extract Doppler signals of detected objects, calculate the basic and quadrature sets of correlation coefficients of one of the selected Doppler signals and correl functions and determine the modules of the radial velocity of objects by the frequency of the extracted Doppler signals, the signs of the radial velocity - by the sign of the phase difference of the Doppler signals isolated from even and odd harmonics, and by the ratios of the constant components of the quadrature and main correlation functions for stationary objects or by the ratios of quadrature and fundamental correlation coefficients for moving objects determine the phase-frequency characteristic of the intermediate frequency signal and calculate the distance to the main object from the steepness linear component, and the difference of distances of the ground and other reflective objects - for periods of periodic components of the phase-frequency characteristics.

In a second embodiment of the method for radar measuring the speeds and coordinates of objects according to the invention, odd and even time sets of reference signals are generated corresponding to a set of average values of the measured ranges, each of which contains respectively only odd or only even harmonics of the modulating signal, the sets of odd and even reference correlation functions are calculated signals and a signal of intermediate frequencies, odd and even constant components and additional Ero signals, by which the first and second full Doppler signals of detected objects are calculated by summing and subtracting the odd and even selected Doppler signals, the phase of one of them being preliminarily changed to π / 2, and the radial velocity modules of objects are determined from the frequencies of the full Doppler signals, signs radial velocity - by the magnitude of the ratio of the levels of the first and second full Doppler signals, and by the levels of the odd or even constant components of the correlation functions for fixed objects or the amplitude of the total Doppler signals for moving objects determine the number of the reference signal in the sets and, accordingly, the distance to stationary or moving objects.

In a third embodiment of the method for radar measuring the velocities and coordinates of objects according to the invention, odd and even temporal sets of reference signals corresponding to a plurality of measured ranges are generated, each of which contains respectively only odd or only even harmonics of the modulating signal, as well as the fundamental and quadrature frequency sets of reference signals , each of which contains one of the harmonics of the modulating signal, calculate the odd and even time sets of functions to the correlation functions of the reference signals and the intermediate frequency signal, as well as the main and quadrature frequency sets of the correlation functions of the reference signals and the intermediate frequency signal, distinguish the odd and even Doppler signals from the correlation functions of the time sets by which the first and second full Doppler signals of the detected objects are calculated by summing and subtracting the odd and even selected Doppler signals, and the phase of one of them is previously changed to π / 2, after which the main and quadra are calculated the frequency sets of the correlation coefficients of the full Doppler signals and the correlation functions of the main and quadrature frequency sets determine the radial velocity moduli of the detected objects by the frequencies of the full Doppler signals, the signs of the radial speed by the magnitude of the ratio of the levels of the first and second full Doppler signals, and by the ratios of quadrature and main correlation coefficients determine the phase-frequency characteristic of the intermediate frequency signal and calculate the range to the main object and according to the steepness of the linear component, and the difference in the ranges of the main and other reflecting objects - according to the periods of the periodic components of the phase-frequency characteristic.

In the fourth embodiment of the method of radar measuring the speeds and coordinates of objects according to the invention, the reception of the reflected signal, its multiplication with the emitted signal and amplification in a given frequency band is carried out at least in one more position, spatially separated from the first, while forming an odd and even time sets of reference signals corresponding to a set of values of measured ranges, each of which contains respectively only odd or only even harmonics of the modulating ignal, calculate for each position the temporal sets of odd and even correlation functions of the reference signals and the intermediate frequency signal, extract the odd and even constant components and Doppler signals from the correlation functions by which the first and second complete Doppler signals are calculated in each position by summing and subtracting the odd and even selected Doppler signals, moreover, the phase of one of them is preliminarily changed to π / 2, after which the total Doppler signal total for all positions is calculated For each detected object, in this case, the phase of the total Doppler signals of the detected objects is stepwise changed by the phase correction value specified for each position until the maximum amplitudes of the total full Doppler signals of the detected objects are reached, the radial velocity modules of the objects are determined from the frequencies of the total full Doppler signals, from the amplitude ratios the first and second total total Doppler signals determine the signs of the radial velocity, and by the levels of the odd or even constant The calculated components of the correlation functions for each stationary object or the amplitude of the total Doppler signals for each moving object determine the number of the reference signal in the sets and, accordingly, the distance to the stationary or moving objects. Additionally, the angular coordinates of each detected object are determined by the phase correction values corresponding to the maximum amplitudes of the total total Doppler signals of the detected objects and the known distance between the positions. In addition, in addition, at each position, the ratios of the amplitudes of the odd and even selected Doppler signals of the detected objects are calculated, which determine the phase differences of the reflected signals received at different positions, and the angular coordinates of each object are determined from the obtained values and known distances between the positions.

In the fifth embodiment of the method of radar measuring the speeds and coordinates of objects according to the invention, the reception of the reflected signal, its multiplication with the emitted signal and amplification in a given frequency band is carried out at least in one more position, spatially separated from the first, while forming an odd and even time the set of reference signals corresponding to the set of values of the measured ranges, each of which contains respectively only odd or only even harmonics of the modulating signal As well as the main and quadrature frequency sets of the reference signals, each of which contains one of the harmonics of the modulating signal, for each position the time sets of the odd and even correlation functions of the reference signals and the intermediate frequency signal are calculated, as well as the main and quadrature frequency sets of the correlation functions of the reference signals and a signal of intermediate frequencies, distinguish odd and even Doppler signals from the correlation functions of time sets by which the first and second full Doppler are calculated signals by summing and subtracting the odd and even selected Doppler signals, moreover, the phase of one of them is preliminarily changed to π / 2, after which the total Doppler signals for each detected object are calculated by all positions, and the phase of the complete Doppler signals of detected objects is stepwise changed the phase correction value specified for each position until the maximum amplitudes of the total full Doppler signals of the detected objects are reached, the total by position correlation functions of the main and quadrature frequency sets, while delaying the correlation functions for a time determined by the magnitude of the phase correction corresponding to the maximum amplitude of the total full Doppler signal of the detected object, after which the main and quadrature frequency sets of correlation coefficients of each of the total full Doppler signals and total correlation functions of the fundamental and quadrature frequency sets, and determine the radial modules soon these objects according to the frequencies of the total total Doppler signals, the signs of the radial velocity - the magnitude of the ratio of the amplitudes of the first and second total full Doppler signals, and the ratios of the quadrature and main correlation coefficients for each harmonic of the modulation frequency determine the phase-frequency characteristic of the intermediate frequency signal and calculate the distance to the main object by the steepness of the linear component, and the difference in the ranges of the main and other reflecting objects - by the periods of the periodic components azochastotnoy characteristics. Additionally, the angular coordinates of each detected object are determined by the phase correction values corresponding to the maximum amplitudes of the total total Doppler signals of the detected objects and the known distance between the positions. In addition, in addition, at each position, the ratios of the amplitudes of the odd and even selected Doppler signals of the detected objects are calculated, which determine the phase differences of the reflected signals received at different positions, and the angular coordinates of each object are determined from the obtained values and known distances between the positions.

The specified technical result is also achieved by the fact that in the system for radar measurement of the speeds and coordinates of objects, containing an antenna-feeder device connected by microwave inputs and outputs, providing radiation of the probe and receiving signals reflected from the measured objects, and a transceiver device that provides the formation of the probe signal, multiplication received signals and amplification of intermediate frequencies of the received homodyne signal, as well as an analog-to-digital converter and the processor, the input of the frequency control of the probe signal and the outputs of the intermediate frequency of the transceiver are connected respectively to the analog output of the processor and the inputs of the analog-to-digital converter, and the processor is endowed with programs for controlling the frequency of the transceiver and calculating the speeds and coordinates of objects, according to the invention, a correlometer connected to the data bus with an analog-to-digital converter and processor, and the correlometer is endowed with programs for the formation of reference signals in, consisting of harmonics of the modulating signal, calculating the correlation functions of the intermediate frequency signal and the reference signals, as well as calculating from them the secondary functions, the parameters of which determine the speeds and coordinates of the reflecting objects.

In the first embodiment of the system according to the invention, the transceiver device comprises a probe signal generator, the output of which is connected to the microwave output of the transceiver device, and the frequency control input is a frequency control input of the transceiver device, a mixer, the first input of which is connected to the microwave input of the transceiver device, the second input is connected to the output probe signal generator, and the output of the homodyne signal is connected through a strip amplifier to the output of the intermediate transceiver frequencies. The antenna-feeder device can either contain a circulator, the first and second shoulders of which are the input and output of the antenna-feeder device, and the third arm is connected to a transceiver antenna, or can be in the form of a receiving and transmitting antenna connected respectively to its output and input of the device. The mixer of the transceiver device of this embodiment can be made according to the diode balanced circuit and have outputs of the sum and difference voltage signals on the diodes, while the output of the difference signal is the output of the homodyne signal, and the transceiver device can additionally contain controlled phase shifter and attenuator connected in series between the microwave output and the input of the device, as well as the interference compensation control circuit, the outputs of which are connected to the control inputs of the phase shifter and attenuator, and in ode connected to outputs of the difference signal and the sum of the balanced mixer.

In the second embodiment of the system according to the invention, the transceiver device is made in the form of an autodyne unit, the output-input and the frequency control input of which are the microwave output-input and the frequency control input of the transceiver device, the output of the homodyne signal of the autodyne unit is connected to the intermediate frequency output of the transceiver device , and the antenna-feeder device is made in the form of a transceiver antenna.

In a third embodiment of the system according to the invention, the transceiver device comprises a probe signal generator, the frequency control input of which is a frequency control terminal of the transceiver device, a feedthrough mixer, the first input of which is connected to the generator output, and the output / input is connected to the microwave output / input of the transceiver device, the output is homodyne the signal of the feedthrough mixer is connected through a strip amplifier to the output of the intermediate frequencies of the transceiver device, and the antenna-feeder The th device is made in the form of a transceiver antenna.

In any of the first three variants of the system according to the invention, the correlometer may have an analog output connected through an additional input of the transceiver device to the input of the strip amplifier, and the correlometer is additionally equipped with programs for measuring the phase-frequency characteristic of the strip amplifier and correcting the phases of harmonics in the reference signals.

In a fourth embodiment of the system according to the invention, the transceiver device comprises a probe signal generator, the output of which is connected to the microwave output of the transceiver device, and the frequency control input is, respectively, the frequency control input of the transceiver device, at least two mixers, the first inputs of which are connected to the microwave inputs of the transceiver device, the second inputs are connected to the output of the probe signal generator, and the outputs are connected through a band amplifier whether to the outputs of the intermediate frequencies of the transceiver. The antenna-feeder device can either contain a circulator, the first and second shoulders of which are the input and the first output of the antenna-feeder device, and the third arm is connected to a transceiver antenna, and at least one more receiving antenna, the outputs of the receiving antennas are connected respectively to other the outputs of the antenna-feeder device, or can be made in the form of a transmitting antenna connected to the microwave input of the antenna-feeder device, and several receiving antennas, the outputs of which are connected respectively but to the microwave outputs of the antenna feeder device.

In a fifth embodiment of the system according to the invention, the transceiver device comprises a probe signal generator, the frequency control input of which is a frequency control input of the transceiver device, a mixer through passage, the first input of which is connected to the generator output, and the input-output is connected to the microwave input-output of the transceiver device, at least at least one more mixer, the first inputs of the mixers are connected to the microwave inputs of the transceiver device, and the second inputs are connected to the output of the gene probe signal, the outputs of the homodyne signal of each of the mixers are connected through strip amplifiers to the outputs of the intermediate frequencies of the transceiver device, and the antenna-feeder device contains a transceiver antenna connected to its output-input, and at least one more receiving antenna connected to his exit.

The essence of the proposed invention lies in the fact that for processing a homodyne signal obtained by multiplying a continuous frequency-modulated probing emitted signal with received signals reflected from the measured objects, correlation methods are used.

The transmitting antenna emits a probing signal generated by the generator (hereinafter referred to as the emitted signal), which in the general case has the form:

The received signal reflected from the object at the output of the receiving antenna has the form:

where E ₀ is the EMF of the probe signal at the terminals of the transmitting antenna, ω = 2π f is the frequency of the emitted signal, ω ₀ = 2π f ₀ = 2π c / λ ₀ is the circular frequency of the central oscillation of the emitted signal, λ ₀ is its wavelength, φ _M (t) is the phase component of the emitted signal due to the frequency modulation of the generator, τ = 2L / s is the delay time of the received reflected signal relative to the emitted, γ is the attenuation coefficient of the signal along the path "transmitting antenna - object - receiving antenna", L is the distance (distance between the object and the radar), s - propagation speed anenii of the electromagnetic signal in the medium.

The emitted and received reflected signals are fed to the inputs of the mixer that performs their multiplication. If the power of the emitted signal coming to the mixer is much higher than the power of the received reflected signal, then the amplitude of the low-frequency (difference) component of the output signal of the mixer is proportional to the amplitude of the received reflected signal, and the phase is equal to the phase difference of the emitted and received reflected signals:

where α _cm is the transfer coefficient of the mixer, Δ φ _M (t, τ) is the component of the phase difference due to the modulation of the frequency of the emitted signal, respectively.

In trigonometric form, the real part of expression (3) is the low-frequency component of the result of the multiplication of the received and emitted signals, then the homodyne signal, takes the form:

where u $\genfrac{}{}{0ex}{}{\text{(hom)}}{\text{0}}$ = α γ E ₀ is the voltage amplitude of the homodyne signal at the output of the mixer.

The first term in square brackets is the product of a constant value (central frequency of the emitted signal) by a constant or slowly changing (compared to the modulation signal) delay time of the received signal indicates the presence of a constant component in the homodyne signal, depending on the delay time (τ) or the Doppler signal frequency. The second term is responsible for the appearance of a periodic component in the homodyne signal, which is a consequence of frequency modulation. The following analysis is carried out for the case when the modulating signal is a harmonic function of time, although other periodic functions can be used for this purpose. If the dependence of the generator frequency on the control voltage is linear, then the instantaneous frequency of the emitted signal is determined by the expression f = f ₀ + Δ f _M = f ₀ + Δ f ₀ sinΩ t. In this case, the second term of expression (4) is determined as

where ψ = 2ψ ₀ sinФ, ψ ₀ = Δ f ₀ / F is the index of the frequency modulation of the probe signal, Φ = Ω τ / 2, Δ f ₀ is the frequency deviation, and Ω = 2π F is the circular modulation frequency.

Having designated the phase difference of the central spectral components of the emitted and received signals as Δ φ = ω ₀ τ = 2ω ₀ L c, we obtain:

или:

or:

According to the theory of Bessel functions (see A.A. Kharkevich. Spectra and analysis. M .: GIFFL, 1962, p. 39) it is true:

Given these relationships and the notation Ф _(N) is the phase of the harmonic of multiplicity N (for one reflecting object Ф _(N) = NФ) we obtain the expression for the spectrum of a homodyne signal:

Here J _(N) (J _(2n-1) , J _(2n) ) are the Bessel functions of the first kind of order N ((N = 2n-1) or (N = 2n)) of the argument ψ, Ф = Ω τ 2 = 2π FLc = 2π LΛ is the phase difference of the modulating signal and the first harmonic signal in the homodyne signal of the mixer (in the IF signal), Λ = cF is the wavelength of the modulating signal, n is a positive integer that determines the harmonic number N of the modulating signal. If the k-th object moves, for example, with a constant radial speed V _k , then the delay time of the reflected signal τ _k changes in time:

and the phase difference of the radiated and received signals of this object Δ φ _{k is} defined as:

- соответствующая начальная разность фаз, (-1)^mV_k - радиальная скорость объекта, которая может быть положительной величиной (объект удаляется, m=0) или отрицательной (объект приближается, m=1), a 2V_kλ ₀=F $\genfrac{}{}{0ex}{}{\text{(д)}}{\text{k}}$ - доплеровский сдвиг частоты принятого сигнала.Here k is the number of the detected object, L $\genfrac{}{}{0ex}{}{\text{(n)}}{\text{k}}$ - the distance of the k-th object at the initial time

is the corresponding initial phase difference, (-1) ^m V _k is the radial velocity of the object, which can be a positive value (the object is moving away, m = 0) or negative (the object is approaching, m = 1), a 2V _k λ ₀ = F $\genfrac{}{}{0ex}{}{\text{(d)}}{\text{k}}$ - Doppler frequency shift of the received signal.

After amplification of the specified spectral components of the homodyne signal and substitution (9) in (7), we obtain the expression for the spectrum of the intermediate frequency (IF) signal with a limited number of harmonics for the case of a single object:

Here K (Ω) is the frequency response of the gain, and K (0) = 0, n _min and n _max are numbers defining the numbers of the lowest (N _min ) and highest (N _max ) given harmonics in the gain band, i.e., in the spectrum IF signal In the presence of a signal from one reflecting object, the dependence of the phase of the harmonic on the frequency, i.e., the phase-frequency characteristic of the IF signal, is linear: (Ф _N = NФ). For the general case, when there are signals from several (k _max ) moving and stationary objects, we obtain from (10):

It is obvious that the spectrum of the IF signal (10-11), like the spectrum of a homodyne signal (7), contains many discrete spectral components - harmonics of the modulating signal (hereinafter - harmonics). The harmonic amplitude (10, 11) varies with the Doppler frequency according to the law of the amplitude-modulated signal with the suppressed carrier, and the phase of the Doppler oscillation is determined by the initial phase difference Δ φ $\genfrac{}{}{0ex}{}{\text{(n)}}{\text{k}}$ Central vibrations of the received and radiated signals.

The amplitude of the even harmonics is determined by the cosine of the phase difference of the central oscillations of the received and emitted signal, and the amplitude of the odd harmonics is determined by the sine. This feature of the spectrum allows us to calculate the main value Δ φ $\genfrac{}{}{0ex}{}{\text{(n)}}{\text{k}}$ through the ratio of the measured amplitudes of the even and odd harmonics, making it possible to determine the sign of the radial velocity of objects by the sign of the phase difference of the Doppler signals. It also allows you to determine the angular coordinates of the object by measuring the phase difference of the signals received in two or more spatial positions. The set of phases Φ _{N of the} harmonics of the IF spectrum carries information about the phase-frequency characteristic of the received signal, that is, about the delay times of the reflected signals (range of objects). In this case, a nonlinear (periodic) dependence Φ _N (N) takes place. The harmonic amplitudes determined by the Bessel functions also depend on the range of the objects. Formulas (10, 11) are valid for both moving and motionless (F $\genfrac{}{}{0ex}{}{\text{(d)}}{\text{k}}$ = 0) objects. Further, the relations for motionless objects will be given only when they do not directly follow from the relations for the general case.

The essence of the proposed method for radar measuring the velocities and coordinates of objects is that correlation analysis methods are applied to the homodyne signal by multiplying it with reference signals and integrating (averaging) the result (see, for example, Theoretical Foundations of Radar. Edited by V.E. Dulevich M.: Soviet Radio, pp. 71-73). From the parameters of the correlation functions obtained in this case, the velocities, ranges and, in embodiments of the invention, the angular coordinates of reflecting objects are calculated. Actually, the correlation functions of the intermediate frequency (IF) signal are determined, which is the amplified part of the spectrum of the homodyne signal, which is essential for measurement purposes, and specially formed reference signals. In this case, the following options (algorithms) of the method are used to process the IF signal.

The first version of the method. Determination of the correlation functions of the IF signal with the reference signals of one or two frequency sets, each of which (signals) imitates the delta function in the frequency domain, being the harmonic of the modulating signal. It is used in cases where a small number of objects are observed. Allows selection of objects by speed.

The second variant of the method. Determination of the correlation functions of the IF signal with the reference signals of time sets, each of which simulates the time function of the expected homodyne signal, being the corresponding set of harmonics of the modulating signal. It is used in cases where a large number of mostly stationary objects are observed. Allows selection of objects by range and speed, but requires a large amount of computation.

The third version of the method. The combination of the first and second options. It is used in cases of observing a large number of moving objects at extreme ranges. Allows selection of objects by speed and range measurement with a minimum amount of calculations.

The fourth and fifth variants of the method are used in cases where the sensitivity of one position is not enough to achieve a given maximum range or it is necessary to determine the angular coordinates of the objects. The fourth variant of the method consists in applying the second variant of the method (processing algorithm) to the IF signals received from the reflected signals received at several spatially separated positions, using the summation and comparison of the correlation functions and secondary functions calculated from the correlation functions.

The fifth variant of the method consists in applying the third variant of the method (processing algorithm) to the IF signals received from the reflected signals received at several spatially separated positions, using the summation and comparison of the correlation functions and secondary functions calculated from the correlation functions.

In the framework of the present invention, other principles of the formation of reference signals while maintaining a common feature are acceptable: each reference signal can contain either only odd or even even harmonics of the modulating signal. The spectra and, therefore, the time functions of the reference signals can be selected, for example, according to the desired shape (depending on the delay time) of the correlation function. During the measurement according to any algorithm, the frequency of the modulating signal F and the deviation of the frequency modulation Δ f ₀ can be changed according to a given program. Since the period of the homodyne signal, as well as the IF signal, is equal to the period of the modulating signal, the accumulation (integration) principle known in pulsed radar can be applied to increase the signal-to-noise ratio (see “Reference”, Volume 1, page 41). In this invention, the positive effect is enhanced by the use of the following algorithm of period-free summation, that is, obtaining an intermediate frequency signal accumulated in a series of periods:

Here t = M ⁽⁺⁾ T + t *, 0≤ t * ≤ T is the time counted from the beginning of the period, T = 1 F is the period of the modulating signal, M ⁽⁺⁾ is the number of the period in the series consisting of M ^{(+ ) max} periods. The increase in signal-to-noise ratio is 10M ^{(+) max} dB. Periodic summation can be combined with periodical subtraction when the signal accumulated in one series is subtracted from the signal accumulated in the previous series. In this case, the signals reflected from stationary objects are suppressed and the signals of moving objects with certain Doppler frequencies are accumulated. The accumulated IF signals are processed according to the following method variants (processing algorithms) of the IF signals.

When implementing the first variant of the method, the main (12-13) and quadrature (14-15) frequency sets of reference signals are formed, each of which contains one of the harmonics of a modulating signal of the form (respectively for odd and even harmonics):

and multiply them separately with a signal of intermediate frequencies (10). The phases of the main and quadrature reference signals differ by π 2. Time averaging of the multiplication results gives for each reflective object two sets (main and quadrature) of the correlation functions, respectively:

where G = K (Ω) U $\genfrac{}{}{0ex}{}{\text{(hom)}}{\text{0}}$ U $\genfrac{}{}{0ex}{}{\text{(on)}}{\text{0}}$ .

Expressions (16-19) represent the correlation functions in the form of the Doppler spectrum. If there are several reflecting objects, by virtue of the superposition principle, the resulting correlation function is equal to the sum of their correlation functions. Each of the correlation functions, thus, may contain a constant component and a spectrum of Doppler signals with different frequencies generated by objects moving at different speeds.

Note. Next, the definitions of reference signals (odd, even, frequency, time) are transferred to the corresponding correlation functions and secondary functions calculated from the correlation functions.

From the sets of correlation functions (16-19), the frequency sets of the amplitude functions of the harmonics of the IF spectrum can be calculated (hereinafter, the harmonic amplitude functions):

and the functions of the phases of the harmonics of the IF spectrum (hereinafter, the functions of the phases of harmonics):

, умножить его на доплеровский сигнал, выделенный из (21) и вычислить постоянную составляющую результата перемножения. Если, например, Ф_(N)=Ф $\genfrac{}{}{0ex}{}{\text{(on)}}{\text{(N)}}$ , a A₀ - коэффициент, то постоянная составляющая А равна (черта означает усреднение по времени)The frequency of the spectral components of the correlation functions (16-19) and harmonic amplitude functions (20-21) is equal to the Doppler frequency, that is, its measurement allows you to measure the speed of the object. By means of filtering, a signal of a constant component or a Doppler frequency (hereinafter referred to as a Doppler signal) can be extracted, that is, a reflecting object is detected, while it is possible to select objects by speed. An analysis of the spectrum of correlation functions or harmonics amplitudes in the full range of Doppler frequencies thus allows the detection of signals of reflecting objects. The phase difference of the Doppler signals of functions (16) and (17), (18) and (19), (20) and (21) is ± π / 2 and is positive if the object is removed. The phase of the Doppler signals of functions (16), (18) and (20) changes to π when the direction of movement of the object changes, while the phase of the Doppler signals of functions (17), (19) and (21) does not change. This property can be used to determine the sign of the Doppler frequency shift, that is, the direction of motion of the object by determining the sign of the phase difference of the Doppler signals contained in the functions of the amplitudes of the even and odd harmonics. For this, it is enough, for example, to isolate the Doppler signal of any of the frequencies from functions (20, 21), change its phase (20) to π / 2 and obtain a signal

, multiply it by the Doppler signal extracted from (21) and calculate the constant component of the multiplication result. If, for example, Ф _(N) = Ф $\genfrac{}{}{0ex}{}{\text{(on)}}{\text{(N)}}$ , a A ₀ - coefficient, then the constant component A is equal to (bar means time averaging)

Thus, the quantity A ^{(±) is} positive for moving objects and negative for approaching ones.

It follows from expressions (10) and (11) that the phase of each harmonic of the frequency spectrum of the IF signal carries information about the range of the object, since Φ = Ω τ / 2 = 2π FL / c = 2π L / Λ. As follows from the theorems on spectra (see A. A. Kharkevich. Spectra and analysis. M .: GIFFL, 1962, p. 26), the dependence of the phase of the harmonic of the modulation frequency in the IF signal on the frequency (i.e., the harmonic number) is determined by the dependence of the difference phases of the emitted and received signals from the center frequency of the emitted signal. In other words, the measurement of the phase-frequency characteristic (PFC) of the harmonics of the IF signal (hereinafter referred to as the phase-frequency characteristic of harmonics) allows us to determine the phase-frequency characteristic of the received signal, the linear component of which calculates the range of the main (brightest) object, and the period of the periodic component - the difference between the ranges of the main and other reflecting objects (see RF Patent No. 2158937, MKI G 01 S 13/40, 13/08, issued November 10, 2000). The phase-frequency characteristic of harmonics is calculated from the set of phases of harmonics (22) by the formula:

where Δ Ф $\genfrac{}{}{0ex}{}{\text{1}}{\text{(N)}}$ is the main value of the harmonic phase N, and M _(N) is zero or a positive integer that is easily determined for each harmonic if the phase difference of the neighboring harmonics does not exceed π. If, for example, for a linear phase response, L <Λ / N ₁ and L> Λ / N ₂ , then M ₁ = 0, and M ₂ is determined by solving a simple system of two equations resulting from (24). Expression (24) is applicable for both stationary and moving objects. In the first case, the phase response of harmonics is determined by the ratio of the constant components of the correlation functions (zero Doppler frequency), and in the second, by the ratio of the amplitudes (levels) of the Doppler components of the correlation functions. These relations are equal to the correlation coefficients of the selected Doppler signal and the correlation functions. If there are several Doppler components generated by different objects in the spectrum of correlation functions, the Doppler signal of each detected object is extracted from the harmonic amplitude function. For example, the Doppler signal of the odd harmonic N ^(em) is determined by filtering methods, which is defined with the notation A ^(em) = GJ _(2n-1) (ψ) by the expression:

Multiplication of the correlation functions of the sets (16-19) with the selected signal (26) and averaging the result over time (i.e., calculating their correlation coefficients) allows us to identify the main and quadrature components of the amplitudes of the signal of the selected Doppler frequency in the correlation functions of the set:

и фазочастотную характеристику гармоник (24), а следовательно, и дальность объекта (или объектов), ответственного за появление доплеровского сигнала выделенной частоты. Применение этого алгоритма позволяет определить разность дальностей объектов, движущихся с равными скоростями.and calculating their relationships, determine the phase of each harmonic

and the phase-frequency characteristic of harmonics (24), and therefore the range of the object (or objects) responsible for the appearance of the Doppler signal of the selected frequency. The application of this algorithm makes it possible to determine the difference in the ranges of objects moving at equal speeds.

Thus, to determine the velocities and ranges of objects according to the first algorithm, sets (12-13), (14-15) of reference signals — harmonics of the modulating signal — are generated, each reference signal is multiplied with the IF signal (10, 11), and sets of basic and quadrature functions are obtained correlations (16-19), and from them the harmonic amplitude functions are calculated. Object detection is carried out by the presence of a constant component or a Doppler signal in the correlation functions or harmonic amplitude functions. From the constant components of the correlation functions, the phases of the harmonics (phase-frequency characteristic of harmonics) determined by the stationary objects are determined and their ranges are calculated. The radial velocity modules of moving objects are determined by the frequency of the Doppler signal extracted from the harmonic amplitude function, and their signs are determined by the signs of the phase difference of the Doppler signals extracted from the amplitude functions of the odd and even harmonics of the IF spectrum. By multiplying the selected Doppler frequency signal with many correlation functions (16-19), the main and quadrature correlation coefficients are determined, and from them the phases of harmonics, i.e. the phase-frequency characteristic of harmonics, from which the ranges of moving objects are calculated.

To implement the second variant of the method, we divide the measured ranges L _min -L _max into P intervals, denote the set of average values of the intervals, that is, the measured ranges L _p , and the set of average values of the expected delay time of the reflected signal - τ _p = 2L _p c, and form the corresponding them odd and even time sets of reference signals corresponding to the expected IF signals. The subscript p denotes the element number of each of the sets. As follows from (10), the spectra of the reference signals of the odd and even sets (the expected IF signals of the odd and even harmonics) should be determined at U $\genfrac{}{}{0ex}{}{\text{(Inverter)}}{\text{0}}$ = U _{0 by} K (Ω) by the expressions:

Where

According to the general rule of optimal processing (matched filtering) of the received signal (see “Reference”, Volume 3, pp. 400-402), to determine the range, it is necessary to find the number of sets p, and from it the value L _p , at which the delayed autocorrelation function has a maximum modulating signal and modulating the received signal. In our case, the range is determined by the maximum correlation function of the IF signal and the reference signal. A feature of this method is the continuity of the emitted and received signals, as well as the fact that the correlation function between the homodyne and reference, artificially created signals is determined, and the correlation functions for signals containing odd and even harmonics are separately calculated. As a result of these operations, two sets (odd and even) of correlation functions will be obtained:

where L _k , ψ _k are the parameters of the real object reflecting the radiated signal. After performing simple trigonometric transformations with (34) and (35), we obtain:

where X _p (L) and Y _p (L) are the basic functions that uniquely determine the correlation functions of the actually received and calculated homodyne signals:

The expressions of the Doppler spectra of the correlation function of the odd and even sets are obtained by substituting (9) in (36) and (37):

It is obvious that both odd and even correlation functions have constant components by which stationary objects are detected, as well as Doppler frequency components, the selection of which by filtering methods detect moving objects and select them by speed. To select objects according to speed, that is, to isolate sets of (41), (42) Doppler signals from signals, the standard methods of spectral analysis are applicable - (analog or digital, parallel or sequential).

выделенный из одной из функций корреляции, например (41), получим, умножив результат на 2π F $\genfrac{}{}{0ex}{}{\text{(д)}}{\text{k}}$ :Here, as in the first algorithm, the sign of the phase difference of the Doppler signals of moving objects (41) and (42) is determined by the sign of the radial velocity, the phase of the signal (41) changes by π when the speed sign changes, and the phase (42) does not depend on the speed sign . Integrating over time (to realize a phase shift by π / 2) the Doppler signal

selected from one of the correlation functions, for example (41), we obtain by multiplying the result by 2π F $\genfrac{}{}{0ex}{}{\text{(d)}}{\text{k}}$ :

Having calculated the sum and difference of the Doppler signal (43) and the Doppler signal U $\genfrac{}{}{0ex}{}{\text{(d) (even)}}{\text{pk}}$ extracted from the correlation function (42), we obtain the first and second full Doppler signals:

Since the functions (Y _p (L) ≈ X _p (L)), it is obvious that for moving objects (m = 0) the signal (45) significantly exceeds the signal (44), that is, the ratio of the levels of the first and second full Doppler extracted signals much more than one. For approaching objects (m = 1) there is a large signal (44), that is, the indicated ratio of signals (45) to (44) is much less than unity. Thus, the magnitude of the ratio of the amplitudes of the first and second full Doppler extracted signals determines the direction of motion of the object, that is, the sign of the radial velocity. In practice, the direction is determined automatically, since when implementing the algorithm (43-45), the signals of approaching and receding objects are separated. In both cases, the useful signal is determined by the sum of the basic functions Z _p (L) = (Y _p (L) + X _p (L)), and the error signal is determined by the function W _p (L) = (Y _p (L) -X _p ( L)), which indicates the coherence of the summation of the Doppler components of the correlation functions, i.e., an increase of 3 dB in the signal-to-noise ratio. To determine the sign of the radial velocity, the algorithm of formula (23) can also be used here with respect to the correlation functions (41) and (42). Similarly, the above algorithm of formulas (43-45) for separating signals with different signs of velocity is applicable in the first version of the method to Doppler signals isolated from harmonic amplitude functions (20) and (21).

The basic functions X _p (L), Y _p (L) and their sum Z _p (L), like the classical autocorrelation functions, have the main maximum at L = L _p side lobes for some other range values. If, for example, there are several motionless objects with different ranges, the greatest values of the constant component will have correlation functions for which L≈ L _p , that is, the actual range of the object differs little from the expected one. Similarly, for moving objects at L≈ L _{p, the} Doppler components of the correlation functions and the amplitude of the total Doppler signals have a maximum. The range of a moving object is determined by the number p of the set of ranges at which the maximum Doppler component of the correlation functions and / or the amplitude of the total Doppler signal due to reflection from the object.

Thus, to detect objects and measure their velocities and ranges, the second variant of the method sets the range of values of L _p , calculates the sets of reference signals (31) and (32) for all values of L _p , multiplies them with the IF signal, obtaining the set of correlation functions (36), (37), (41), (42). For stationary objects, the detection and determination of range is carried out by the number of the set at which the maximum constant component of at least one of the correlation functions is maximum. For moving objects, the total Doppler signals (44) and (45) are calculated, the object is detected by the maximum value of the amplitude of one of them, the element number p and, accordingly, the range L _{p are} determined. The accuracy of the range measurement in this algorithm is limited by the width of the main lobe of the used base function and the relative level of the side lobes. To select objects by speed and measure velocities, they analyze the spectrum of at least one of the signals of sets (41), (42), (44) or (45), and the radial velocity module of the object is determined from the measured value of the extracted frequency. The sign of the radial velocity is determined by the magnitude of the ratio of the amplitudes of the first and second full selected Doppler signals.

и фазочастотную характеристику (24), а следовательно, и дальность объекта (или объектов), ответственного за появление доплеровского сигнала выделенной частоты. Этим алгоритмом достигается существенное (относительно первого алгоритма) уменьшение погрешности измерения, поскольку сигналы (44) или (45), полученные в результате оптимальной фильтрации, имеют лучшее отношение сигнал/шум.The third variant of the method combines the operations of the second and first variants, allowing to obtain complete information about the speeds and ranges of moving objects with a significantly smaller amount of calculations. The detection of objects and the determination of the magnitudes and signs of their velocities in this embodiment are determined using the operations of the second embodiment, and the range is calculated using the operations of the first embodiment of the method. For this, the range of measured ranges L _min -L _{max is} divided into P intervals, the number of which can be one to two orders of magnitude less than in the second algorithm. For the set of average values of the expected ranges, the corresponding odd and even time sets of reference signals of the form (31) and (32) corresponding to the expected IF signals are formed. Multiplying the reference signals (31) and (32) with the IF signal (10, 11), we obtain two sets (odd and even) of the correlation functions (41) and (42), select the Doppler components from them, and the full Doppler signals from them (44) and (45), which are used to detect objects and determine their radial velocity. The main and quadrature frequency sets of reference signals are formed, each of which contains one of the harmonics of a modulating signal of the form (12-15) and multiply them separately (as in the first version of the method) with an intermediate frequency signal (10, 11). The correlation functions obtained by time averaging have the form (16-19). The main and quadrature sets of correlation coefficients (27-30) are calculated by multiplying the correlation functions of the main and quadrature sets (16-19) with the full selected Doppler signal of the detected object of the form (44) or (45). By calculating their relations, the phases of harmonics are determined

and the phase-frequency characteristic (24), and therefore the range of the object (or objects) responsible for the appearance of the Doppler signal of the selected frequency. This algorithm achieves a significant (relative to the first algorithm) reduction of the measurement error, since the signals (44) or (45) obtained as a result of optimal filtering have the best signal-to-noise ratio.

In some cases, the implementation of the specified values of the limiting range is difficult either because of the technical complexity of obtaining a sufficiently high level of power of the emitted signal, or because of administrative restrictions on the level of this power. To solve this problem, a multi-position technique is used, that is, coherent summation of signals received at several spatially separated positions (see “Handbook”, Volume 4, p. 193). Since the amplitudes of the received signals reflected from the objects and the power of uncorrelated noise are summed up, each additional receiving position increases the signal-to-noise ratio by 3 dB. Considering that the limiting range is proportional to the root of the fourth degree of radiated power, doubling the limiting range can be achieved by receiving the reflected signal in eight positions. Since the distances traveled by the reflected signal from the object to different positions, as well as the phase differences of the central oscillations of the signals received in them, depend on the angle of direction to the reflecting object, it becomes possible to determine the angular coordinates of the objects.

The possibility of coherent summation of signals received at several, for example, two positions A and B, is based on the ratio obtained for the phase difference of the central oscillations of the signals received at these positions (see Saibel A.G. Radar Basics. M .: Soviet Radio, 1961, p. 165):

- угол между нормалью отрезка АВ и направлением на объект, D - расстояние между позициями А и В.Where

is the angle between the normal of the segment AB and the direction to the object, D is the distance between positions A and B.

This ratio can be easily extended to an arbitrary number of receiving positions. The probe signal is emitted from an arbitrary position, which in the particular case may coincide with one of the receiving positions.

The signals received at each position are multiplied (mixed) with the emitted signal according to the general method algorithm, the homodyne signals are amplified in a given band, receiving intermediate frequency signals of the form (10, 11) for each position. For two positions, for example, we have:

сигналы (47) и (48) отличаются либо по амплитудам четных и нечетных гармоник (для неподвижных объектов), либо по фазам доплеровских составляющих.For D << Λ and equal amplitudes

signals (47) and (48) differ either in the amplitudes of even and odd harmonics (for stationary objects) or in the phases of the Doppler components.

The essence of the fourth variant of the method of the algorithm consists in applying the algorithm of the second variant of the method to the processing of signals received during multi-position reception. In this case, the measured ranges are divided into P intervals, the odd and even time sets of reference signals (31) and (32) corresponding to the average ranges of the intervals are formed, which are multiplied in each position with the IF signals (47-48) obtained at this position. As a result of these operations, after simplifications and simple trigonometric transformations, we obtain, similarly to (41) and (42), two sets (odd and even) of correlation functions in each position:

From the Doppler signals of moving objects isolated from the correlation functions, the first and second complete selected Doppler signals of the k-th object are obtained at each position in the same way (43-45):

, получая первый и второй суммарные полные доплеровские сигналы:and summarize them, shifting the phase in one of the positions (for example, B) by the amount of phase correction

receiving the first and second total total Doppler signals:

когда второй косинус в уравнениях (58-59) равен единице, достигается максимальный (для двух позиций удвоенный) уровень полного доплеровского сигнала. Направление наилучшего приема сигналов, отраженных от движущихся объектов, изменяется (путем, например, ступенчатого изменения

) относительно направления нормали к отрезку, соединяющему позиции приема. Как и во втором алгоритме, по номеру множества р, суммарный сигнал (58) или (59) которого максимален, определяется дальность обнаруженного объекта, по доплеровской частоте любого из суммарных полных доплеровских сигналов - модуль радиальной скорости, а по величине отношения амплитуд первого и второго суммарных полных доплеровских сигналов определяется направление движения объекта, то есть знак радиальной скорости.Obviously, by choosing the magnitude of the phase correction

when the second cosine in equations (58-59) is equal to unity, the maximum (doubled for two positions) level of the full Doppler signal is achieved. The direction of the best reception of signals reflected from moving objects changes (by, for example, stepwise change

) relative to the direction of the normal to the segment connecting the reception position. As in the second algorithm, by the number of the set p, the total signal (58) or (59) of which is maximum, the range of the detected object is determined, the radial velocity modulus is determined from the Doppler frequency of any of the total total Doppler signals, and the magnitude of the ratio of the amplitudes of the first and second total total Doppler signals determines the direction of motion of the object, that is, the sign of the radial velocity.

физически нереализуем, поэтому для определения расстояния из функций корреляции (49-52) вычисляют суммарные по позициям нечетную и четную функции корреляции:For stationary objects, when the Doppler frequency is zero, the phase shift by

physically unrealizable, therefore, to determine the distance from the correlation functions (49-52), the odd and even correlation functions total by positions are calculated:

From the expressions (61-62) it follows that the direction of the best reception of signals reflected from stationary objects coincides with the direction of the normal to the segment connecting the receiving position. The range of fixed objects is determined by the number of the set of total odd and (or) even correlation functions.

, а из соответствующей максимальному значению сигналов величины

и известного расстояния между позициями приема определяют угловую координату по формуле, следующей из (46):To determine the angular coordinate of a moving detected object, the total Doppler signals (first or second depending on the sign of the radial velocity) are determined for several values of the phase correction value

, and from the value corresponding to the maximum value of the signals

and the known distance between the receiving positions determine the angular coordinate according to the formula following from (46):

The angular coordinate of both a moving and a stationary object can also be calculated from the correlation functions (49-52). Using the ratios (49) to (50), and (51) to (52), the phase differences of the signals emitted and received at the positions are calculated

and phase difference received in the positions of the signals

from which the angular coordinate is determined:

). По доплеровским частотам суммарных полных доплеровских сигналов определяют радиальную скорость объектов, а по отношению амплитуд первого и второго суммарных полных доплеровских сигналов - знак радиальной скорости. Для обеспечения наилучшего приема суммарные полные доплеровские сигналы определяют для нескольких значений фазовой коррекции

(например ступенчато изменяя ее величину), а по значению

, при котором их амплитуда максимальна, определяют угловую координату по формуле (63). Как и в четвертом варианте способа, угловая координата может вычисляться по алгоритму (64-64).The fifth variant of the method uses the operations of the third variant in relation to multi-position reception, allowing to obtain complete information about the coordinates and speeds of moving objects with a significantly smaller amount of calculations. In this case, the measurement of the magnitude and sign of the speed is determined by the operations of the second variant, the range is determined by the operations of the first variant, and the angular coordinates are determined by the operations of the fourth variant of the method, and these operations are carried out with the total signals obtained by adding the correlation functions of the same name and secondary functions of all positions. The range of measured ranges L _min -L _{max is} divided into P intervals, the number of which can be one to two orders of magnitude less than in the fourth embodiment. For the set of average values of the expected ranges, the corresponding odd and even time sets of reference signals of the form (31) and (32) are formed equal to the corresponding expected IF signals. Multiplying (31) and (32) with IF signals (47-48), we obtain for each position two sets (odd and even) of correlation functions (49-53), and of these, complete Doppler signals of the form (44) and ( 45) and total positional total Doppler signals used to detect reflective objects. Before summing, as in the fourth embodiment, the phase of the full Doppler signals is shifted by the phase correction value specified for each position (for two positions, the phase is shifted in one of them, for example, B -

) The radial velocity of objects is determined from the Doppler frequencies of the total total Doppler signals, and the sign of the radial velocity is determined from the amplitudes of the first and second total full Doppler signals. To ensure the best reception, the total total Doppler signals are determined for several phase correction values

(for example, stepwise changing its value), and by value

at which their amplitude is maximum, determine the angular coordinate by the formula (63). As in the fourth variant of the method, the angular coordinate can be calculated according to the algorithm (64-64).

To determine the range, a Doppler signal of a detected object of the form (58) or (59) is isolated. The main and quadrature frequency sets of reference signals are formed, each of which contains one of the harmonics of the modulating signal of the form (12) and (13), (14) and (15), and multiply them separately with intermediate frequency signals (47-48) of one or several positions (as in the first version of the method), getting the correlation function, the spectral components of which are determined by the expressions:

, для чего, например, соответствующие функции корреляции задерживаются на время, связанное с заданной величиной фазовой коррекции соотношением

. Эта операция обеспечивает полное суммирование доплеровских составляющих функций корреляции частотных множеств. Полученные суммарные функции корреляции

,

,

и

перемножают с одним из суммарных полных сигналов (61-62), например

, a результат усредняют по времени (аналогично (27-30). Из полученных в результате коэффициентов корреляции основного и квадратурного множеств (черта означает усреднение по времени):The correlation functions are then summed over the positions, and as with the summation of the total Doppler signals, the phase of the Doppler components is shifted by the amount of phase correction

, for which, for example, the corresponding correlation functions are delayed by the time associated with a given phase correction value by the relation

. This operation provides a complete summation of the Doppler components of the correlation functions of frequency sets. The resulting total correlation functions

,

,

and

multiplied with one of the total total signals (61-62), for example

, a the result is averaged over time (similar to (27-30). From the resulting correlation coefficients of the main and quadrature sets (bar means time averaging):

и фазочастотную характеристику гармоник

из параметров которой вычисляют дальности объектов. Применение этого алгоритма позволяет определить разность дальностей объектов, движущихся с равными скоростями.determine the many phases of the harmonics of the IF signal

and phase-frequency response of harmonics

from the parameters of which the ranges of objects are calculated. The application of this algorithm makes it possible to determine the difference in the ranges of objects moving at equal speeds.

The system for implementing the above method for measuring the range and speed of objects contains, like the prototype, an antenna-feeder device (AFU) that emits a sounding and receives a reflected signal, a homodyne transceiver device (PPU), which performs the functions of generating a frequency-modulated microwave sounding signal, multiplication (mixing) with it the received reflected signal and amplification of the received homodyne signal, as well as a processor that generates a modulating signal and determines the coordinates and speed reflective objects. An intermediate frequency (IF) signal is generated at the output of the IF frequency converter, which contains the specified part of the homodyne signal spectrum amplified by the IF frequency amplifier. A significant difference of the proposed device is that a correlometer made on the basis of a digital signal processor endowed with programs for generating reference signals consisting of harmonics of the modulating signal and for calculating the correlation functions of the IF signal and reference signals, as well as secondary functions calculated from the correlation functions (functions of amplitudes and phases of harmonics of the IF spectrum, constant components of the correlation functions, isolated and full additional Rovsky signals, correlation coefficients, and the total of all the positions and functions of signals). Information about the correlation functions and secondary functions in digital form is transmitted via the data bus to the processor, which calculates and displays (if necessary, transmits to the external information network) the coordinates and speeds of the detected objects.

The output and inputs of microwave signals (or common output-input) of the control panel are connected to the input and outputs (or common input-output) of the AFU. The analogue input for controlling the frequency of the probing signal of the control panel is connected to the analogue output of the processor. The output of the intermediate frequency signal (hereinafter referred to as the IF output) of the control panel is connected to the ADC input. The correlometer, processor, ADC and display are connected by a digital data bus (hereinafter referred to as the data bus). In the framework of the present invention, five structural variants of a radar system for measuring the speeds and coordinates of objects are provided. The first three variants of the system implement any of the first three variants of the measurement method, the fourth and fifth version of the system - the fourth or fifth variants of the method.

In the first version of the structure of the PPU system, the probe signal generator (hereinafter referred to as the generator) having a frequency control input connected to an output of the PPU microwave output has a mixer, the first and second inputs of which are connected respectively to the PPU microwave input and the generator output, and the output to the strip input amplifier. Microwave output and input PPU are connected respectively to the input and output of the AFU. In this embodiment, the AFU structure contains either one transceiver antenna and a ferrite circulator, the shoulders of which are connected to the antenna, as well as to the input and output of the AFU, or two antennas connected to the input and output of the AFU.

In the second version of the PPU structure, the functions of generating the probing signal and multiplying the received signal with it are performed by the autodyne unit (see IM Kogan. Near Radar. M: Soviet Radio, pp. 39-40, 46-52, 70-120; EM Gershenzon et al. General characteristics and features of the autodyne effect in oscillators. “Radio engineering and electronics”, Volume XXVII, 1982, No. 1, p. 104), the common microwave output-input of which is connected to the common input through the PPU output-input - exit AFU. The homodyne signal to the input of the strip amplifier can be removed from the power circuit of the autodyne node.

In the third version of the system structure in the PUF, a feedthrough mixer is used, made, for example, in the form of a section of a waveguide in which mixing diodes are connected in parallel with a narrow wall. The distance between the diodes along the waveguide axis is λ / 2. The generator output is connected to the first flange of the mixer, and the second flange is connected to the PPU output-input. The coupling of the diodes with the waveguide, depending on the distance to the narrow wall, is selected so that 25% of the generator power is dissipated in the first and second diodes, which is done if the coupling of the second diode provides for the selection of one third of the transmitted power. This arrangement of the diodes provides antiphase, that is, compensation, of the voltages released on the diodes caused by the amplitude modulation of the generator and the addition of homodyne signals. This version of the PPU, like the autodyne, has a common output-input, to which the AFU is connected by a common input-output. In the second and third version of the structure, an AFU made in the form of a transceiver antenna is used.

To implement the fourth and fifth variants of the measurement method, the fourth and fifth variants of the system structure are applicable, differing respectively from the first or third variants of the system structure by the presence of additional mixers in the PUF, the first and second inputs of each of which are connected to the PUF microwave inputs and the generator output, respectively . The outputs of the mixers are connected through additional strip amplifiers to the outputs of the inverter. Each of the outputs of the inverter of the control panel is connected to the input of the corresponding ADC connected to the data bus. The total number of IF outputs of the PPU is equal to the number of its microwave inputs, the number of mixers and IF amplifiers. In these variants of the structure, it is possible to use one ADC, the input of which is connected to the output of the switch. The control input of the switch by the processor program in this case is connected to the data bus, and the signal inputs to the outputs of the inverter of the control panel. AFUs used in the fourth and fifth variants of the system structure have several antennas located on the same line (in one measurement) if it is necessary to measure one angular coordinate. If both angular coordinates are measured, the antennas are arranged in two dimensions, for example, in the three corners of a square.

In the fourth embodiment of the system structure, the generator output is connected to the microwave output of the PUF. In this embodiment, the AFU can contain either one transceiver antenna and a ferrite circulator, one arm of which is connected to the transceiver antenna, and the other two to the input and the first output of the AFU, and receiving antennas, which are one less than the number of FAC mixers, or several antennas, one of which, the transmitting one, is connected to the input of the AFU, and the rest, the number of which is equal to the number of PPU mixers, are connected to the outputs of the AFU.

The PUF of the fifth version of the system structure is the PUF of the third option, supplemented by several mixers, and has one microwave output-input and several microwave inputs. The AFU contains one transceiver antenna connected to the output-input of the AFU, and several receiving antennas connected to the outputs of the AFU.

The proposed method and system can reduce the influence of interference due to spurious leakage of the emitted signal into the channel for receiving a useful signal reflected from the measured objects. Causes of interference may be unwanted reflections from inhomogeneities of the AFU or closely located objects, interference due to the low radio-tightness of the nodes and transmission lines of the AFU and PUF, and its consequence is a violation of the balance properties of the mixer, and, consequently, a decrease in the sensitivity of the receiving channel. With a radiated power level of 50 milliwatts typical of traffic control radars, the power reflected on the mixer will be 2 milliwatts with an antenna SWR of 1.5. The importance of the problem is obvious, since the generator power directed to the heterodyne input of the mixer has the same order. Moreover, the modulation of the frequency of the emitted signal leads to amplitude modulation of the received signal, which can significantly reduce the sensitivity of the receiving channel, that is, to reduce the limiting range. The feature of the proposed method, in particular, the practical absence of a constant component and the first harmonic in the useful homodyne signal when they prevail in the interference signal, allows, firstly, to estimate the noise level, and secondly to create a compensating input at the input of the receiving channel a signal equal to the interference in amplitude and opposite in phase.

The interference compensation signal is obtained by branching a part of the generator signal by directing it to the input of the mixer, and certain values of its amplitude and phase are set. The influence of the interference is reduced to zero if the phases of the interference and the compensating signal are opposite at any time and the amplitudes are equal. In practice, it is sufficient that the interference signal is absent in the homodyne signal.

Compensation for interference is carried out, for example, as follows. The mixer of the transceiver device is performed according to a diode balanced circuit with separate terminals from each diode. The diodes through the second (heterodyne) input of the mixer in antiphase feed the emitted signal from the generator E _g = E _{0 g cosω} t. Through the first (signal) input to the diodes in the same phase, the sum of the interference E _n = E _0n cos (ω t + φ _n ) and the compensation signal E _com = E _{0 com} cos (ω t + φ _com ), the component of the residual signal E _ost = E _0ost cos (ω t + φ _ost) wherein:

The phase of the residual signal is π / 2 when the condition:

The voltages of the frequency of the probing signal on the first and second diodes of the mixer have the form:

If the current-voltage characteristic of the mixer diodes is quadratic, then for the low-frequency component voltages on the load resistances R _n = R _n1 = R _{n2, which are} separate for each diode, we obtain:

The sum (signal of the sum) and the difference (signal of the difference) of the voltage across the diodes are equal, respectively

From the expressions (82-83) it follows:

- The difference signal, which is the low-frequency part of the homodyne signal, characterizes the level of interference arising from reflections and leakage in the paths of the emitted and received signals.

- If, by adjusting the phase of the compensating signal, to ensure that condition (81) is satisfied, then the balanced properties of the mixer are restored, and the interference signal is eliminated from the spectrum of the homodyne signal. In this case, however, the level of power dissipated by the diodes is not controlled.

- The most advanced is the compensation scheme, where the phase of the compensating signal by the phase control system is set according to the criterion that the difference signal (83) is equal to zero, and the amplitude is set by the amplitude control system according to the criterion of the given signal level of the sum (82).

- To control the phase and amplitude of the compensation signal, analog or digital control circuits for compensating for interference of simultaneous or alternating actions can be used. This may be, for example, a combination of analogue systems of automatic phase control (ARF) and amplitude (ARA).

- In the simplest cases, when the decrease in sensitivity due to the influence of the amplitude noise of the generator is insignificant, it is possible to use a single-diode mixer with one input in the PUF that multiplies the residual and received signals. In this case, the compensating signal is used as a local oscillator, and there is no direct connection of the mixer and generator.

The features of the proposed method and device make it possible to exclude the influence on the accuracy of nonlinearity of the phase-frequency characteristic, which is usually estimated through the value of the non-uniformity of the group delay time (GW). This nonlinearity leads to a distortion of the phases of the harmonics of the frequency spectrum of the IF signal, i.e., the phase-frequency characteristic of the IF signal, and as a result, the appearance of an error in the measurement of ranges. For periodic measurement of the real phase-frequency characteristic in a variant of the system structure, the correlometer is supplemented by an analog output connected to an additional input of the control panel connected to the input of the strip amplifier. At the input of a strip amplifier, test signals of a frequency set of the form are given simultaneously or alternately through an additional analog output of the correlometer

Past amplifier signals

, который определяют, вычисляя основной и квадратурный коэффициенты корреляции сигналов:get a frequency dependent phase shift

, which is determined by calculating the basic and quadrature correlation coefficients of the signals:

and of these, the phase dependence of the frequency, that is, the real phase-frequency characteristic of the strip amplifier:

The calculation of the deviations of the measured phase response from the ideal linearized one allows you to calculate the corrections that must be introduced into the phases of the harmonics of the reference signals in order to compensate for the nonlinearity of the phase response.

Thus, the task of ensuring high sensitivity and accuracy of measurement at the minimum cost of means of transport radar is realized according to the invention through the use of correlation methods for analyzing a homodyne signal, which, with the utmost simplicity of the analog complex, allow optimal processing of a continuous signal at almost any accumulation time.

The invention is further explained using the drawings, where:

figure 1 presents the General structural diagram of a system for measuring the speeds and coordinates of objects,

figure 2 shows the basic block diagram of an algorithm for detecting and measuring the speed of objects,

figure 3 presents a diagram of the connected transceiver and antenna-feeder devices of the first embodiment of the system structure for measuring speeds and coordinates of objects,

figure 4 presents a diagram of the connected transceiver and antenna-feeder devices of the second variant of the structure of the system for measuring speeds and coordinates of objects,

figure 5 presents a diagram of the connected transceiver and antenna-feeder devices of the third variant of the structure of the system for measuring speeds and coordinates of objects,

figure 6 presents a diagram of the connected transceiver and antenna-feeder devices of the fourth variant of the structure of the system for measuring speeds and coordinates of objects,

7 is a diagram of the connected transceiver and antenna-feeder devices of the fifth embodiment of the system structure for measuring the speeds and coordinates of objects,

on Fig presents a diagram of a transceiver device of the system of the first variant of the structure with the interference compensation circuit,

figure 9 presents the equivalent circuit of the balanced mixer, modified for use in the compensation circuit of interference,

figure 10 presents graphs characterizing the dependence on the distance of the full correlation functions calculated for the second variant of the method.

The system for measuring the speeds and coordinates of objects (see figure 1) contains an antenna-feeder device (AFU) 1, a transceiver device (PPU) 2, an analog-to-digital converter (ADC) 3, correlometer 4, processor 5 and display 6. Microwave the output (in variants of the output-input structure) of the control unit 2 is connected to the input (in the variants of the input-output structure) of the AFU 1, the outputs of the AFU 1 are connected to the inputs of the control panel 2. The inputs of the analog-to-digital converter 3 are connected to the outputs of the control panel of the control panel 2.

In this case, several ADCs connected to the corresponding outputs of the control unit 2 can be used, as well as a single ADC connected either directly to the single output of the control unit ПУУ 2, or through a switch (not shown), which is part of the ADC 3 and controlled by the correlometer 4, - several inverter outputs. ADC 3, correlometer 4, processor 5 and display 6 are connected by a digital data bus 7 (hereinafter referred to as the data bus), which can be connected to an external information network. The control unit 2 has an input for controlling the frequency of the probe signal connected to the analog output of the processor 5. In the system variants, the correlometer 4 may have an analog output of the test signal connected to the second input of the control unit.

The proposed method for measuring the speeds and coordinates of objects using the proposed system is as follows. The transceiver 2 generates a continuously periodically modulated frequency probe microwave signal, transmits it to the antenna-feeder device 1, through which they radiate it into space and receive a signal reflected from objects in one or more spatial positions. Using the processor 5, a periodic control signal of the frequency of the probe signal (modulating signal) is generated and transmitted in analog form to the first input of the control panel 2, and digitally through the data bus to the correlometer 4. The received signals are transmitted to the transceiver 2, where they are separately multiplied (mix) them with the emitted signal and, isolating the low-frequency (difference) components of the multiplication results, they obtain homodyne signals, amplify a given part of their spectrum and direct them to the corresponding outputs of the intermediate frequency (IF) control unit 2. Using an analog-to-digital converter 3, the IF signals are transferred to the digital domain and transmitted through the data bus 7 to the correlometer 4. Based on the modulating signal, using the special program of the correlometer 4, reference signals of frequency and (or) time sets are generated consisting of harmonics of the modulation frequency, and calculate the correlation functions of the reference signals and the IF signals, as well as secondary functions (functions of the amplitudes and phases of the harmonics, constant and Doppler components, full Doppler signals, correlation coefficients (If multilateration) receiving the aggregate at the positions of the correlation function, the function of harmonics and full Doppler signals). The obtained information is transmitted to the processor 5, which determines the speed and coordinates of the detected objects. If necessary, the information received by the processor is displayed on the display 6 or transmitted via the data bus 7 to an external information network for further processing.

Figure 2 shows a block diagram of a basic detection algorithm, as well as measuring the speeds and coordinates of reflecting objects by the system shown in figure 1. All operations shown in the diagram are performed in the digital domain. By means of the correlometer program, an IF signal of the form (11) (block 2) and one of the reference signals (block 4) are multiplied (block 3): the main or quadrature frequency sets of the form (12-15) for a certain value of N, or even or odd time sets of the form (31-32) for a certain value of p, and the result is integrated (block 5), obtaining the corresponding correlation function of the form (16-19, 34-35), secondary functions are calculated (block 6), by the level of which reflective objects are detected (block 9), and according to the parameters, their speeds and coordinates are calculated (block 10). In block 9, through the program of the processor 5, a comparison is made of the level of the received signal with a given level U * and a conclusion is made about the presence or absence of a reflecting object. (The signal level is the value of the constant component or the amplitude of the Doppler component of the corresponding function). If the signal level is less than the level U *, that is, there is no signal reflected from the object, change (block 7) the value of p (or N) and repeat the cycle (blocks 2-8). By the presence of the Doppler signal (for stationary objects - a constant component) in the correlation function or in the secondary function, a conclusion is made about the detection of the object (block 9). By measuring the frequency of the selected Doppler signal, determine the radial velocity of the detected object. The sign of the phase difference of the odd and even Doppler signals (23) or the magnitude of the ratio of the first and second full Doppler signals (58, 59) determines the sign of the radial velocity. If the measurement is carried out according to the second algorithm, then the distance of the detected object is determined by the value of p. When measuring according to the first or third algorithm, for the set of values of N, correlation coefficients of the form (27-30) are calculated, the phase-frequency characteristic is determined from them according to the algorithm (24), and from it - the range of the objects. In the algorithm of FIG. 2, sequential calculation of the correlation functions of frequency or time sets is applied. In the presence of sufficient computing power of the correlometer, simultaneous (parallel) calculation of the correlation functions can be applied.

The ability to detect an object and determine its range using the second algorithm is illustrated in Fig. 10, which shows the calculated dependences of the full (sum of odd and even) correlation functions of the time set for two values of the expected range: 300 and 900 meters. The calculations are made for the traffic control radar. Obviously, the main maxima of the correlation functions occur when the expected L _p and the actual range are equal, and the width of the main lobe for this case is Δ L _p = 12 m. Therefore, if the range of measured ranges is 1200 meters, for example, divided into 100 equally spaced intervals, average distance L _p which is a multiple of 12 meters, which generate reference signals for odd and even time and calculate a plurality of sets of correlation functions of the IF signal and a reference signal, the signal reflected from an object at the distance uu L _p ± 6 m, determine the maximum level of the corresponding correlation function for which it is detected and its range is defined.

PPU 2, depending on the features of the application, can be performed in several structurally different variants that determine the options for the structure of the system. Any of the first three variants of the structure of the system can implement any of the first three algorithms of the method, any of the fourth and fifth variants of the structure implement both the fourth and fifth algorithms.

In the first embodiment (figure 3), the structure of the PPU 2 has a microwave output and input, and the AFU 1 has an input and output connected to them. PPU 2 contains a probe signal generator 8 (hereinafter referred to as a generator) having a frequency control input, which is a frequency control input of a transceiver device, a mixer 9 and a strip amplifier 10. The AFU 1 contains either a ferrite circulator 11 and a transceiver antenna 12 or two antennas: a transmitting and receiving (not shown), the input and output of which are respectively the input and output of the AFU 1. The output of the generator 8 is connected to the second input of the mixer 9 and to the microwave output of the PUF, the first input of the mixer 9 is connected to the microwave move PUF and homodyne signal output coupled to an input bandpass amplifier 10. The bandpass amplifier output is connected to the IF output of the transceiver device 2. The first and second arms of the circulator 11 are input and output of antenna-feeder device and a third arm connected to a transceiver antenna.

In the first embodiment of the device, the frequency-modulated probe signal is generated by the generator 8, fed through the microwave output to the input of the AFU 1 and emitted by its transceiver (or in the transmitting version) antenna. The reflected signal received by the transceiver (or receiving) antenna from the output of the AFU 1 through the microwave input of the PPU 2 is fed to the mixer 9, where it is mixed (multiplied) with the signal of the generator 8, that is, with the radiated signal. Received at the output of mixer 9, a homodyne signal of the form (11) is amplified in a given frequency band by a strip amplifier 10 and fed to the inverter of the control panel 2. The system, the structure of which is constructed according to the first embodiment, is the most universal and can be used, for example, in police radars with a level radiated power of 50-100 milliwatts.

In the second embodiment (see figure 4) of the system structure, the transceiver device 2 is made in the form of an autodyne unit 13, the output-input and the frequency control input of which are respectively the microwave output-input and the frequency control input of the transceiver device 2. PPU 2 also contains , a strip amplifier 10, and the antenna-feeder device 1 is made in the form of a transceiver antenna. The input-output of the AFU 1, i.e., the antenna, is connected to the output-input of the control unit 2, and the output of the homodyne signal of the autodyne unit 13 is connected to the output of the drive unit 2 through the strip amplifier 10. , for example, Votoropin S.D., Yurchenko V.I. Autodyne on Gunn diodes and devices based on them. "Electronic Industry", 1998, issue 1-2, pp. 110-115; Votoropin S.D., Noskov V.Ya. Transceiver modules on low-current Gunn diodes for autodyne systems. “Electronic Technology”, Ser. Microwave Te nick, 1993, vol. 4 (458), pp. 70-72). The probe signal is generated, for example, by the Gunn diode and emitted by the AFU transceiver antenna 1. The received AFU 1 reflected signal is fed to the Gunn diode, where due to its non-linearity it is multiplied with the radiated signal. The homodyne signal is extracted, for example, from the power supply circuit of the Gunn diode using a transformer (not shown). As in the first embodiment, the homodyne signal is amplified by a strip amplifier 10 and output through the output of the IF PPU 2. The autodyne version of the system is the simplest and cheapest, however, due to its low sensitivity and correspondingly small ultimate range, it can be recommended for obstacle sensors when driving a vehicle in reverse.

In the third embodiment (see Fig. 5), the AFU 1 systems are made, as in the second embodiment, in the form of a transceiver antenna 12, the input-output of the antenna 12 is the input-output of the AFU 1, which is connected to the output-input of the control panel 2. The transceiver 2 contains a generator 8, the frequency control input of which is the frequency control input of the transceiver 2, the mixer 14 and the strip amplifier 10. The output of the generator 8 is connected to the input of the mixer 14, the output-input of which is connected to the output-input of the control panel 2. The output of the homodyne signal P the bypass mixer is connected to the input of the strip amplifier 10, the output of which is the output of the IF PPU 2. The through mixer 14 can be made in the form of a segment of the waveguide (not shown), one flange of which is connected to the generator 8 and is the input, and the other flange is the output-input mixer 14 connected to the output-input of the control panel 2. In this case, two mixing diodes are connected to the waveguide segment, the distance between them along the waveguide axis is a quarter of the wavelength. The connection of the diodes with the waveguide is selected so that a quarter of the generator power is dissipated at the first diode closest to the input, and a third of the transmitted power is dissipated at the second one. The low-frequency outputs of the diodes are connected and connected to the output of the homodyne signal of the mixer. It is easy to see that the in-line mixer (similar to the balanced one) suppresses the amplitude noise of the generator, although the signal power loss during transmission (and reception) is about 3 dB. In this embodiment of the device, a frequency-modulated probe signal is generated by the generator 8, fed through the mixer 14 and the microwave output-input of the PPU 2 to the input-output of the AFU 1 and emit a transceiver antenna. The reflected signal received by the transceiver antenna from the output of the AFU 1 through the microwave output-input of the PPU is fed to the output-input of the mixer 14, where it is mixed (multiplied) with the signal of the generator 8, that is, with the radiated signal. The homodyne signal of the form (11) obtained at the output of the mixer is amplified in a given frequency band by a strip amplifier and output through the output of the IF PPU 2. The third version of the system structure is used where the level of radiated power is limited to a few milliwatts, and low cost should be combined with high technical characteristics.

The fourth and fifth variants of the system structure are intended for the implementation of multi-position reception algorithms and are formed from the structures of the first and second variants, respectively, by the addition of AFUs with one or more receiving antennas, and the PUFs with the corresponding number of mixers and strip amplifiers.

In the fourth embodiment of the system structure (see FIG. 6), the AFU 1 contains transmitting 15 and several receiving antennas 16a, 16b, 16c, the inputs and outputs of which are the inputs and outputs of the AFU 1. In the version of the AFU, the transmitting and one receiving antenna are replaced by a circulator ( not shown), the first and second shoulders of which are the input and one of the outputs of the AFU 1, and the third is connected to the transceiver antenna. PPU 2 contains a probe signal generator 8 having a frequency control input, which is a frequency control input of a transceiver 2, several mixers 9a, 9b, 9c and strip amplifiers 10a, 10b, 10c. The output of the generator 8 is connected to the second input of each of the mixers 9 and to the microwave output of the PUF 2, the first inputs of the mixers 9a, 9b, 9c are connected to the microwave inputs of the PUF 2, and the outputs are connected respectively to the inputs of the strip amplifiers 10a, 10b, 10v. The outputs of the strip amplifiers are connected to the IF outputs of the transceiver device 2. The number of receiving antennas 16, mixers 9, strip amplifiers 10 and the IF outputs are equal to the number of receiving positions.

In the fourth embodiment of the device, a frequency-modulated sounding signal is generated by the generator 8, fed through a microwave output to the input of the AFU 1 and emitted by its transmitting (or, in the embodiment, transceiving) antenna. The reflected signals received by the antennas from the outputs of the AFU 1 through the microwave inputs of the PPU 2 are fed to the mixers 9a, 9b, 9c, where they are mixed (multiplied) with the signal of the generator 8, that is, with the radiated signal. Received at the output of the mixer homodyne signals of the form (47-48) are amplified in a given frequency band by strip amplifiers 10a, 10b, 10c and fed to the outputs of the IF PPU 2.

In the fifth embodiment of the system structure (see Fig. 7), the AFU 1 has transceiver 12 and several receiving antennas 16a, 16b, 16c, the input-output of the transmitting and outputs of the receiving antennas are the input-output and outputs of the AFU 1. PPU 2 contains a probe signal generator 8 having a frequency control input, which is a frequency control input of a transceiver 2, a feedthrough mixer 14, several mixers 9a, 9b, 9c and strip amplifiers 10, 10a, 10b, 10c. The output of the generator 8 is connected to the second inputs of each of the mixers 9a, 9b, 9c and to the input of the in-line mixer 14, and the output-input of the latter is connected to the microwave output-input of the PPU. The first inputs of the mixers 9a, 9b, 9c are connected to the microwave inputs of the PUF 2, and the outputs of the homodyne signal of the feed mixer 14 and the mixers 9a, 9b, 9c are connected to the inputs of the strip amplifiers 10, 10a, 10b, 10v. The outputs of the strip amplifiers 10, 10a, 10b, 10c are connected to the IF outputs of the transceiver 2. The number of antennas 12 and 16, the mixers 9, the strip amplifiers 10 and the IF outputs is equal to the number of receiving positions.

In the fifth embodiment of the device, a frequency-modulated sounding signal is generated by the generator 8, fed through the feedthrough mixer 14 and the microwave output-input to the input-output of the AFU 1 and emit a transceiver antenna. The reflected signals received by the antennas from the input-output and outputs of the AFU 1 through the microwave inputs and the output-input of the PPU 2 are fed to the mixers 14, 9a, 9b, 9c, where they are mixed (multiplied) with the signal of the generator 8, that is, with the emitted signal. The homodyne signals of the form (47-48) obtained at the output of the mixers are amplified in a given frequency band by strip amplifiers 10 10a, 10b, 10c and fed to the outputs of the IF PPU2.

In the fourth and fifth versions of the system structure, the correlometer program is supplemented with algorithms for calculating the total total Doppler signals (58, 59), the total correlation functions (61, 62), and the total correlation coefficients (75-78). The processor program calculates the speed and range of objects from the summed signals; if necessary, the program is supplemented by algorithms for calculating the angular coordinates of objects (63) (66).

The transceiver circuit of the system of the first embodiment of the structure with the interference compensation circuit due to leakage of the emitted signal into the reception channel of the reflected signal (see Fig. 8), in addition to the generator 8, the mixer 19 of the strip amplifier 10, further comprises an electrically controlled attenuator 17 and a phase shifter 18, as well as compensation compensation scheme 22 (QMS). Compensation control circuitry 22 may comprise, for example, a differential low-frequency amplifier (VLF) 20 and a low-frequency amplifier (VLF) 21. The attenuator 17 and the phase shifter 18 are connected in series between the microwave output and the input of the PPU 1 by the microwave inputs and outputs (i.e., between the generator output 8 and the first input of the mixer 19), and the control inputs are connected to the outputs of the QMS 22. The inputs of the LPS 20 are connected to the second and fourth terminals (sum signal), and the input of the ULF 21 is connected to the third terminal (difference signal) of the balanced mixer 19, and the output respectively through the outputs of the QMS 22 to the control inputs of the attenuator and phase shifter. An equivalent circuit of a balanced mixer 19, modified to receive the signals of the sum and voltage difference of the mixing diodes, is shown in Fig.9. Transformer Tr. together with capacitances C ₁ , C ₂ provides the diodes D ₁ , D ₂ with the generator voltage U _g in antiphase, and the voltage of the received signal U _c (and interference U _n ) in phase. This diagram fully describes the electrical characteristics of any hybrid microwave range connection. The constant components of the currents of the diodes D ₁ , D ₂ , respectively, flow through the resistance R ₁ , R ₂ , causing a voltage drop on them. As a result, a voltage appears between terminals 2 and 4 equal to the sum of the voltage drops across the resistances (sum signal), and between terminals 1 (common) and 3 - a voltage equal to their difference (difference signal). Compensation of the interference signal is as follows. A chain of attenuator 17 and phase shifter 18 forms a compensating signal with the frequency of the emitted signal. Compensation occurs when the amplitudes of the compensating signal and the interference are equal, and the phases differ by π, that is, they are opposite. This state is achieved by the operation of two analog automatic control systems: phase (ARF) and amplitude (ARA) of the compensating signal. The ARF system consists of a balanced mixer 19 (mismatch sensor), ULF 21 and phase shifter 18 (actuator). Regulation is carried out according to the criterion that the signal of the difference of the mixer 19 is equal to zero. The ARA system consists of a balanced mixer 19 (mismatch sensor), ALCL 20 and an attenuator 17 (actuator). Regulation is carried out according to the criterion of equality to a given signal level of the sum of the mixer 19. During the operation of the ARF system, the signal of the difference of the mixer 19, defined by expression (83), is amplified by the ULF 21 and fed to the control input of the phase shifter 18, which changes the phase of the compensating signal until the zero level is reached signal difference. During the operation of the ARA system, the signal of the sum of the mixer 19, defined by expression (82), is amplified by the use of a differential filter 20 and is fed to the control input of the attenuator 17, which changes the amplitude of the compensating signal until a specified signal level of the sum is reached. As a result of these processes, interference elimination at the input of the balanced mixer is achieved. The described compensation scheme can be used in the control unit of the fourth version of the system, while all mixers are replaced by balanced ones 19, between the output of the control unit 2 and each input of the control unit 2 additional series attenuators 17 and phase shifters 18 are connected, each of which is connected to the outputs of the corresponding FCS 22 connected to the outputs of balanced mixers 19. The number of attenuators 17, phase shifters 18 and CMS 22 is equal to the number of positions.

In any of the first three variants of the structure, the possibility of measuring and compensating for the nonlinearity of the phase-frequency characteristic of a strip amplifier can be realized. For this, the correlometer can be supplemented with an analog output, which is connected to the input of the strip amplifier through the second input of the PPU 2, and is endowed with a program for generating a test signal from the harmonics of the modulating signal at this output, as well as calculating the basic and quadrature correlation coefficients of the output test signal of the strip amplifier 10 and input test signal, as well as determining from them its phase-frequency characteristic. If necessary, the program for generating reference signals of the correlometer can be supplemented with a linearization block for the measured phase response, calculating the phase difference of the linearized and measured phase response at the harmonics frequencies, and correcting the phase of the harmonics of the reference signals by the value of the calculated difference between the real and linearized phase response of the strip amplifier.

Thus, the variants of the proposed method and system for radar measuring the speeds and coordinates of objects allow solving the problems of creating several types of equipment for ensuring road safety: from the simplest obstacle sensors to radars that determine the speeds, ranges and angular coordinates of objects of traffic. The combination of a homodyne transceiver with a simple frequency modulation of the probing signal and a correlation analysis of the received signal will make it possible in the near future to create a number of inexpensive and small-sized radars. The rapid development of digital signal processing technology will allow, in the future, within the framework of the proposed technical ideology, to solve increasingly complex problems while reducing the cost of systems.

Claims (21)

1. The method of radar measurement of the speeds and coordinates of objects, including the radiation of a periodically modulated frequency probe signal, receiving signals reflected from objects, multiplying the emitted and received signals, amplification in a given frequency band obtained by multiplying a homodyne signal and analyzing the received intermediate frequency signal, different the fact that they form the main and quadrature frequency sets of reference signals, each of which contains one of the harmonics of the modulating s In addition, the main and quadrature frequency sets of correlation functions of the reference signals and the intermediate frequency signal are calculated, from which the set of harmonic amplitude functions of the spectrum of the intermediate frequency signal is calculated, from the obtained harmonic amplitude functions, at least two even and odd harmonics, the Doppler signals of the detected objects, calculate the basic and quadrature sets of correlation coefficients from the correlation function and one of the selected Doppler signals and determine the radial modules speed of objects - according to the frequency of the extracted Doppler signals, signs of radial speed - by the sign of the phase difference of the Doppler signals isolated from the even and odd harmonics of the spectrum of the intermediate frequency signal, and by the ratios of the constant components of the quadrature and main correlation functions for stationary objects or by the ratios of quadrature and fundamental correlation coefficients for moving objects determine the phase-frequency characteristic of the intermediate frequency signal and calculate the distance to the main object - by cr Tiznit linear component, and the difference of distances of the ground and other reflective objects - for periods of periodic components of the phase-frequency characteristics of the intermediate frequency signal. 2. A method for radar measuring the velocities and coordinates of objects, including emitting a periodically modulated frequency probe signal, receiving signals reflected from objects, multiplying the emitted and received signals, amplifying in a given frequency band the homodyne signal obtained by multiplying, and analyzing the received intermediate frequency signal, different the fact that form an odd and even time sets of reference signals corresponding to the set of average values of the measured ranges, each of which contains only odd or even even harmonics of the modulating signal, respectively, the sets of odd and even correlation functions are calculated from the odd and even reference signals and the intermediate frequency signal, and the odd and even constant components corresponding to them and the odd and even are correlated from the odd and even correlation functions even Doppler signals, by which the first and second full Doppler signals of detected objects are calculated by adding and subtracting the odd and four of the selected Doppler signals, and the phase of one of them is preliminarily changed to π / 2, the radial velocity modules of the objects are determined by the frequencies of the full Doppler signals, the signs of the radial speed are determined by the magnitude of the ratio of the levels of the first and second full Doppler signals, and by the levels of the odd or even constant component correlation functions for stationary objects or the amplitude of the total Doppler signals for moving objects determine the number of the reference signal in sets and, accordingly, the range to motionless or moving objects. 3. A method of radar measurement of the speeds and coordinates of objects, including the radiation of a periodically modulated sounding signal, receiving signals reflected from objects, multiplying the emitted and received signals, amplification in a given frequency band obtained by multiplying a homodyne signal and analyzing the received intermediate frequency signal, different the fact that they form an odd and even time set of reference signals corresponding to the set of values of the measured ranges, each and from which respectively contains only odd or even even harmonics of the modulating signal, as well as the main and quadrature frequency sets of the reference signals, each of which contains one of the harmonics of the modulating signal, calculate the time sets of the odd and even correlation functions, respectively, from the odd and even time sets of the reference signals and the signal of intermediate frequencies, and also calculate the main and quadrature frequency sets of correlation functions, respectively, from the main and quadrature h random sets of reference signals and a signal of intermediate frequencies, isolated from the timed odd and even sets of correlation functions corresponding to them odd and even Doppler signals, which calculate the first and second full Doppler signals of detected objects by summing and subtracting the odd and even selected Doppler signals, and the phase one of them is preliminarily changed to π / 2, after which the main and quadrature frequency sets of the correlation coefficients of the full Doppler signals and correlation functions of the main and quadrature frequency sets, determine the radial velocity modules of the detected objects by the frequencies of the full Doppler signals, the signs of the radial speed by the value of the ratio of the levels of the first and second full Doppler signals, and the ratios of the quadrature and main correlation coefficients of the full Doppler signals and functions correlations determine the phase-frequency characteristic of harmonics of the intermediate frequency signal and calculate the distance to the main object - according to the slope ineynoy component, and the difference of distances of the ground and other reflective objects - for periods of periodic components of the phase-frequency characteristics of the intermediate frequency signal harmonics. 4. A method for radar measuring the velocities and coordinates of objects, including emitting a periodically modulated frequency probe signal, receiving signals reflected from objects, multiplying the emitted and received signals, amplifying a homodyne signal obtained in the given frequency band and analyzing the received intermediate frequency signal, different the fact that the reception of the reflected signal, its multiplication with the radiated signal and amplification in a given frequency band is carried out, at least e e in one position spatially spaced from the first one, at that, odd and even time sets of reference signals are formed corresponding to a set of values of measured ranges, each of which contains respectively only odd or only even harmonics of the modulating signal, time sets of odd and even are calculated for each position correlation functions, respectively, from odd and even time sets of reference signals and a signal of intermediate frequencies, isolated from time sets of odd and even correlation functions, the corresponding odd and even constant components and the odd and even Doppler signals, by which the first and second full Doppler signals are calculated at each position by summing and subtracting the odd and even selected Doppler signals, and the phase of one of them is preliminarily changed to π / 2, after which the total Doppler signals total for all positions are calculated for each detected object, while the phase of the complete Doppler signals detected is stepwise changed objects to the phase correction value specified for each position until the maximum amplitudes of the total full Doppler signals of the detected objects are reached, the radial velocity modules of the objects are determined from the frequencies of the total full Doppler signals, the signs of the radial speed are determined from the ratio of the amplitudes of the first and second total full Doppler signals, and the levels odd or even constant components of the correlation functions for each stationary object or in amplitude of the full Doppler signals s for each moving object is determined in the reference signal number and accordingly sets the range to the fixed or moving objects. 5. The method according to claim 4, characterized in that in addition to the magnitude of the phase correction corresponding to the maximum amplitude of the total total Doppler signals of the detected objects, and the known distance between the positions determine the angular coordinates of each detected object. 6. The method according to claim 4 or 5, characterized in that in addition, in each position, the ratio of the amplitudes of the odd and even selected Doppler signals of the detected objects is calculated, which determine the phase differences of the reflected signals received at different positions, and by the obtained values and known distances between positions determine the angular coordinates of each object. 7. A method for radar measuring the velocities and coordinates of objects, including emitting a periodically modulated frequency probe signal, receiving signals reflected from objects, multiplying the emitted and received signals, amplification in a given frequency band obtained by multiplying a homodyne signal and analyzing the received intermediate frequency signal, different the fact that the reception of the reflected signal, its multiplication with the radiated signal and amplification in a given frequency band is carried out, at least e e in one position spatially spaced from the first, at the same time, odd and even temporal sets of reference signals are formed corresponding to the set of values of the measured ranges, each of which contains respectively only odd or only even harmonics of the modulating signal, as well as the main and quadrature frequency sets of reference signals , each of which contains one of the harmonics of the modulating signal, calculate for each position the time sets of odd and even correlation functions, respectively From the odd and even time sets of the reference signals and the intermediate frequency signal, as well as the main and quadrature frequency sets of the correlation functions, respectively, from the main and quadrature frequency sets of the reference signals and the intermediate frequency signal, the corresponding odd and even Doppler signals are extracted from the correlation functions of the time sets by which the first and second full Doppler signals are calculated by adding and subtracting the odd and even selected Doppler signals, moreover, the phase of one of them is preliminarily changed by π / 2, after which the total Doppler signals total for all positions for each detected object are calculated, and the phase of the full Doppler signals of the detected objects is stepwise changed by the phase correction value specified for each position until the maximum amplitudes of the total full Doppler signals of detected objects, calculate the total position correlation functions of the main and quadrature frequency sets, while delaying the function correlations for the time determined by the magnitude of the phase correction corresponding to the maximum amplitude of the total total Doppler signal of the detected object, after which the main and quadrature frequency sets of the correlation coefficients of each of the total full Doppler signals and the total correlation functions of the main and quadrature frequency sets are calculated in each position, the modules are determined radial velocity of objects - according to the frequencies of total total Doppler signals, signs of radial velocity - according to other ratios of the amplitudes of the first and second total complete Doppler signals, and the ratios of the harmonics of the intermediate frequencies are determined from the ratios of the quadrature and fundamental correlation coefficients for each harmonic of the modulation frequency and the distance to the main object is calculated based on the steepness of the linear component, and the difference between the ranges of the main and other reflecting objects - according to the periods of the periodic components of the phase-frequency characteristic of harmonics. 8. The method according to claim 7, characterized in that in addition to the magnitude of the phase correction corresponding to the maximum amplitude of the total total Doppler signals of the detected objects, and the known distance between the positions determine the angular coordinates of each detected object. 9. The method according to claim 7 or 8, characterized in that in addition, in each position, the ratio of the amplitudes of the odd and even selected Doppler signals of the detected objects is calculated, which determine the phase differences of the reflected signals received at different positions, and by the obtained values and known distances between positions determine the angular coordinates of each object. 10. A system for radar measuring the speeds and coordinates of objects, comprising an antenna-feeder device connected by microwave inputs and outputs, providing radiation from the probe and receiving signals reflected from the measured objects, and a transceiver device that provides the formation of a sounding signal, multiplying received signals and amplifying intermediate frequency of the received homodyne signal, as well as an analog-to-digital converter and processor, the input of the frequency control of the probing signal and the outputs of the intermediate frequency of the transceiver are connected respectively to the analog output of the processor and the inputs of the analog-to-digital converter, and the processor is endowed with programs for controlling the frequency of the transceiver and calculating the speeds and coordinates of the objects, characterized in that a correlometer connected to the analog-digital data bus is inserted into it a converter and a processor, and the correlometer is endowed with programs for generating reference signals consisting of harmonics of the modulating signal, eniya correlation functions of the intermediate frequency signal and a reference signal, and calculating, from these secondary functions, the parameters that determine the speed and position of reflective objects. 11. The system of claim 10, wherein the transceiver device includes a probe signal generator, the output of which is connected to the microwave output of the transceiver device, and the frequency control input is a frequency control input of the transceiver device, a mixer, the first input of which is connected to the microwave input of the transceiver device , the second input is connected to the output of the probe signal generator, and the output, which is the output of the homodyne signal, is connected through a strip amplifier to the output of intermediate frequency transceiver. 12. The system according to claim 11, characterized in that the antenna-feeder device comprises a circulator, the first and second arms of which are the input and output of the antenna-feeder device, and the third arm is connected to a transceiver antenna. 13. The system according to claim 11, characterized in that the antenna-feeder device is made in the form of receiving and transmitting antennas connected respectively to its output and input. 14. The system according to any one of paragraphs.11-13, characterized in that the mixer of the transceiver device, made according to the diode balanced circuit, has outputs of the sum and difference voltage signals on the diodes, while the difference signal output is the output of the homodyne signal, and the transceiver device contains controlled phase shifter and attenuator connected in series between the microwave output and the input of the transceiver device, as well as a noise compensation control circuit, the outputs of which are connected to the control inputs phase shifter and attenuator, and the inputs are connected to the outputs of the difference signals and the sum of the mixer. 15. The system of claim 10, characterized in that the transceiver device is designed as an autodyne node, the output-input and frequency control input of which are the microwave output-input and frequency control input of the transceiver device, the output of the homodyne signal of the autodyne node is connected through a strip amplifier to the output of the intermediate frequencies of the transceiver device, and the antenna-feeder device is made in the form of a transceiver antenna. 16. The system of claim 10, wherein the transceiver device comprises a probe signal generator, the frequency control input of which is a frequency control input of the transceiver device, a feedthrough mixer, the first input of which is connected to the output of the probe signal generator, and the output-input is connected to a microwave the output-input of the transceiver device, the output of the homodyne signal of the flow mixer is connected through a strip amplifier to the output of the intermediate frequencies of the transceiver device, and the The feeder antenna is designed as a transceiver antenna. 17. The system according to any one of claims 10-16, characterized in that the correlometer has an analog output connected through an additional input of the transceiver device to the input of the strip amplifier, and is additionally equipped with programs for measuring the phase-frequency characteristic of the strip amplifier and correcting the phases of harmonics in the reference signals. 18. The system of claim 10, wherein the transceiver device comprises a probe signal generator, the output of which is connected to the microwave output of the transceiver device, and the frequency control input is, respectively, the frequency control input of the transceiver device, at least two mixers, the first inputs of which are connected with microwave inputs of the transceiver device, the second inputs are connected to the output of the probe signal generator, and the outputs are connected through the strip amplifiers to the outputs intermediate frequencies of the transceiver device. 19. The system according to p. 18, characterized in that the antenna-feeder device contains a circulator, the first and second arms of which are the input and the first output of the antenna-feeder device, and the third arm is connected to a transceiver antenna, and at least one more the receiving antenna, the outputs of the receiving antennas are connected respectively to other outputs of the antenna-feeder device. 20. The system according to p. 18, characterized in that the antenna-feeder device is made in the form of a transmitting antenna connected to the microwave input of the antenna-feeder device, and several receiving antennas, the outputs of which are connected respectively to the microwave outputs of the antenna-feeder device. 21. The system of claim 10, wherein the transceiver device comprises a probe signal generator, the frequency control input of which is a frequency control input of the transceiver device, a feedthrough mixer, the first input of which is connected to the output of the probe signal generator, and the input-output is connected to a microwave the input-output of the transceiver device, at least one mixer, the first inputs of the mixers are connected to the microwave inputs of the transceiver, and the second inputs are connected with the output of the probe signal generator, the outputs of the homodyne signal of each of the mixers are connected through strip amplifiers to the outputs of the intermediate frequencies of the transceiver device, and the antenna-feeder device contains a transceiver antenna connected to its output-input, and at least one more receiving antenna, connected to its output.

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