The phase signal,

 

(57) Abstract:

The invention relates to radar, radio navigation and can be used for determining the angular coordinates of the radiation source photomanipulating (QPSK) signal. The technical result of the proposed device is the resolution of contradictions between the requirements of accuracy and unambiguity of the reference angular coordinates of the source radiation QPSK signal by applying two measurement scales: a phase measurement scale is accurate but ambiguous, and timeline measurement is rough, but clear. The phase signal includes first and second receiving antennas, the first and second receivers, the first, second and third multiplier products, the first and second narrowband filters, Phaser 90, a phase detector, the first and second indicators, the correlator block adjustable delay, lowpass filter, extreme regulator and the measuring device. 3 Il.

The invention relates to radar, radio navigation and can be used for determining the angular coordinates of the radiation source photomanipulating (FM) signal.

Known devices for measurements of radiation sources of the signals (the Torno measurement. Edited by P. A. Agadzhanova and others - M.: Owls. radio, 1969, S. 244-245; Kinkelin I. E. and other Phase method for the determination of coordinates. - M.: Owls. radio, 1979; Space radio systems. Ed. by S. I. Bychkova.- M: Owls. radio, 1969, 134-137 C., Fig. 2.3.9 and others).

As a basic device selected phase signal (Cosmic radio systems. Ed. by S. I. Bychkova.- M: Owls. radio, 1969, S. 135, Fig. 2.3.9).

The specified direction finder inherent contradiction between the requirements of accuracy and unambiguity of the reference angular coordinates. Indeed, according to the formula

< / BR>
where d is the distance between the receiving antennas (test database);

- wave length;

- the angle of arrival of radio waves;

the phase signal, the more sensitive to the measurement of the angular coordinates, the larger the relative size of the database. But with increasing d/ decreases the value of the angular coordinate at which the phase difference exceeds a value of 2, i.e., comes the ambiguity of the reference angle .

The objective of the proposed device is the resolution of contradictions between the requirements of accuracy and unambiguity of the reference angular coordinates of the radiation source QPSK signal by applying two measuring.

The solution of this problem is achieved by the fact that the phase signal containing series-connected first receiving antenna and the first receiver, cascaded second receiving antenna and a second receiver, consistently enabled Phaser 90othe phase detector and the first indicator is equipped with three multiplier products, two narrow-band filters, block adjustable delay, lowpass filter, a second indicator, extreme regulator and measuring device and to the output of the first receiver sequentially connected to the first multiplier, a second input connected with the output of the first receiver and the first narrowband filter, the output of which is connected to the input of the phase shifter 90oto the output of the second receiver are connected in series, a second multiplier, a second input connected with the output of the second receiver and the second narrowband filter, the output of which is connected to a second input of the phase detector, the output of the second receiver serially connected adjustable delay unit, a third multiplier, a second input connected to the output of the first receiver, the lowpass filter and the measuring device, you the and to the second output of which is connected to the second indicator.

A structural scheme of the phase direction finder shown in Fig. 1. The direction-finding feature is shown in Fig. 2. The relative locations of the antennas is shown in Fig. 3.

The phase signal contains consistently included the first receiving antenna 1, the first receiver 3, the first multiplier 5, the first narrow-band filter 7, the phase shifter 9 90othe phase detector 10 and the first indicator 11, cascaded second receiving antenna 2, the second receiver 4, the second multiplier 6 and the second narrow band filter 8, the output of which is connected to the second input of the phase detector 10. The output of the second receiver 4 are connected in series block 13 adjustable delay, the third multiplier 14, a second input connected to the output of the first receiver 3, the filter 15 of the lower frequencies and the measuring device 18. The output of the filter 15 of the lower frequencies through extreme regulator 17 is connected to the second input unit 13 adjustable delay. The second output unit 13 adjustable delay connected to the second indicator 16. Unit 13 adjustable delay, the multiplier 14 and the filter 15 of the lower frequencies form the correlator 12.

Phase is SUB>ct+ak(t)+a1],

< / BR>
where U1(t), U2(t-),c,1,2, Tc- envelope, carrier frequency, initial phase, and the duration of the signals;

the delay time of the signal arriving at antenna 2 relative to the signal arriving at the antenna 1;

d - the distance between the receiving antennas 1 and 2, located on the same line (test database);

- the angle of arrival of radio waves;

c is the speed of light;

k(t) = {,} - manipulated component phases, reflecting the law of phase manipulation in accordance with the modulating function (ID) M(t), andk(t) = const for ke< t < (k+1)eand may change abruptly at t = ke, i.e., at the boundaries between elementary parcels (k=1,...,N-1);

eN - the length and number of basic assumptions which form the signal duration Tc(Tc= Ne);

2=ce;

with the outputs of the receiving antennas 1 and 2 are received at the inputs of the receivers 3 and 4, where they are amplified and limited in amplitude:

u3(t) = U0cos[ct+ak(t)+a1],

u4(t) = U0cos[ct+ak(t-)+2], 0 t tc.

where U0the threshold limit.


u5(t) = U1cos(20t+21)

u6(t) = U1cos(20t+22), 0 t tc,

where

K1- transfer coefficient multiplier products;

which provide a second harmonic of the channel stress.

It should be noted that the width of the spectrum of fcthe received QPSK signal is determined by the duration of etheir basic packages: whereas the width of the spectrum of the second harmonic is determined by the duration of Twithsignals:

Therefore, when the multiplication of QPSK signals themselves on their range of rolled N times:

This circumstance allows to select harmonic oscillations u5(t) and u6(t) using narrowband filters 7 and 8, filtering out much of the noise and interference.

If harmonic oscillations u5(t) and u6(t) with the output of narrow-band filters 7 and 8 apply directly to the phase discriminator 10, the output of the latter will receive

< / BR>
where

K2- gain of the phase detector (phase discriminator).

From the above correlation can be seen that the voltage at the output of the discriminator depends on the angle , however, due to the fact that the cosine function is even, the sign is not zavisit the phase shifter 9, changing the phase of the harmonic signal u5(t) on the 90o. In this case, the voltage error at the output of the phase discriminator is determined by the expression

< / BR>
Dependence is usually called the direction-finding characteristic (Fig. 2).

The slope in the region of small angles , where the characteristic is almost linear, equal

< / BR>
Thus, the slope is determined by the ratio d/. Increase the base d and decreasing wavelength increase the slope K however, this also increases the ambiguity of the reference angle.

The slope determines the magnitude of the dead zone 2minfor a given value of the noise UW(Fig. 2).

The number of zones of ambiguity, i.e., regions where the phase difference is changed by an amount equal to 2, is determined by the ratio

< / BR>
For a single reference, you need to choose n=1, i.e., to choose the measuring base on the basis of conditions

< / BR>
Error finding , i.e., the error in the measurement of the angle , at a given measurement accuracy of the phase difference can be determined on the basis of expressions:

< / BR>
< / BR>
From the last expression we see that the error finding depends not only one, and at high it could be very significant.

Based on the above expressions it is possible to choose the ratio /d or at a fixed value - the value of large measurement database, providing the necessary accuracy for determining the angle .

Thus is formed a phase scale reference angular coordinates: accurate but ambiguous. The measurement results are recorded by the indicator 11.

Voltage u3(t) and u4(t) from the outputs of the receivers 3 and 4 simultaneously fed to two inputs of the correlator 12, consisting of a block 13 of the adjustable delay of the multiplier 14 and the filter 15 of the lower frequencies. Obtained at the output of the correlator 12 correlation function R () measured by the measuring device 18 has a maximum at the value entered adjustable delay

= t2-t1,

where t1and t2- time of signal distances R2and R1before the second 2 1 and the first receiving antenna.

The maximum value of R(t) is supported using extreme regulator 17 acting on the second input unit 13 adjustable delay. Scale unit 13 adjustable delay (index corner) is calibrated directly in values of angular coordinates East is Ximum correlation function R().

The value of the angular coordinate is recorded by the indicator 16.

Thus is formed the timeline reference angular coordinates: rough but clear.

Essentially measuring scales measured the full phase difference:

F = m+,

where m is the number of complete cycles of the measured phase difference, defined timeline;

the phase difference measured by the phase scale (0 2).

Thus, the proposed phase signal compared to the base object and other similar devices provides the resolution of contradictions between the requirements of accuracy and unambiguity of the reference angular coordinates. This is achieved by using two measurement scales: a phase scale - accurate but ambiguous, and the timeline is a rough but clear. Thus due to the convolution of the spectrum of the received QPSK signal increases the sensitivity, noise immunity and accuracy of measuring the phase difference between the signals passed two channel phase signal. And phase jumps in the received QPSK signals do not affect the results of the measurements.

The proposed phase direction finder works in a similar way and using the Converter of the second antenna, the first receiver cascaded second receiving antenna, a second receiver, cascaded phase shifter 90, the phase detector and the first indicator, characterized in that it is equipped with three multiplier products, two narrow-band filters, block adjustable delay, lowpass filter, a second indicator, extreme regulator and measuring device, and between the output of the first receiver and the input of the phase shifter 90 consistently included the first multiplier, the second input is also connected to the output of the first receiver and the first narrow-band filter between the output of the second receiver and the second input of the phase detector cascaded second multiplier, the second input is also connected to the output of the second receiver and the second narrowband filter, the output of the second receiver serially connected adjustable delay unit, a third multiplier, a second input connected to the output of the first receiver, the lowpass filter and the measuring device, the output of lowpass filter through extreme regulator connected to the second input of the adjustable delay unit, to the second output of which is connected to the second indicator.

 

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FIELD: radiolocation.

SUBSTANCE: device has divider and calibrating voltage source, and also has multiplier and converter of guiding cosine signal of radio signal direction relatively to plane of phased antennae grid opening Ux = cos(90-α0) to signal of guiding cosine of radio signal direction relatively to normal line to plane of phased antennae grid opening Uz = cosα0, serving for automatic correction of calibrating voltage on basis of law Uz=cosα0.

EFFECT: higher precision.

2 dwg

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