RU2073878C1 - Phase direction finder of scanning sources - Google Patents

Abstract

FIELD: radio direction finding, can be used in radio beacon navigation systems. SUBSTANCE: the phase direction finder, having two antennas, each connected to the input of the phase meter via the receiver, divider whose first input is connected to the phase meter output and the divider output is connected to the indicator, and a direction finding transconductance input terminal, additionally uses an amplitude discriminator, differentiator, source directional pattern scanning angular rate meter, second and third dividers, modulus generating device, subtracter multiplier, direction finder directional pattern width input terminal and a squarer; the output of one of the receives via series-connected amplitude discriminator and source directional pattern angular rate meter is connected to the second input of the second divider, whose first input via the differentiator is connected to the phase meter output; the output of the second divider via the modulus generating device is connected to the first input of the multiplier, whose second input via the squarer is connected to the output of the third divider. The first input of the third divider is connected to the source directional pattern width input terminal. The second input of the third divider is connected to the direction finder directional pattern width input terminal; the second input of the first divider is connected to the output of the subtracter, whose input is connected to the multiplier output, and the second input of the subtracter is connected to the direction finding transconductance input terminal. EFFECT: enhanced accuracy. 1 dwg

Description

 The invention relates to direction finding and can be used in beacon navigation systems.

где Dv разность фаз;
d база;
l длина волны.There is a fairly wide range of possible implementations of the phase difference method for determining the angular position of radiation sources. Basically, these devices contain two antennas spaced at some distance, called the "base", each of which is connected through a receiver to the input of the phase meter connected to the indicator. Such a phase direction finder (see [1] p. 131, Fig. A2.9) is closest to the claimed one. Bearing is evaluated in such a direction finder based on the measured value of the phase difference and its a priori known dependence on the angular position of the source — direction finding characteristic (HR):

where Dv is the phase difference;
d base;
l wavelength.

Из (2) и (1) следует обычно используемый алгоритм пеленгования:

Стремление увеличить дальность действия фазовых пеленгаторов приводит к необходимости увеличения апертур их антенн, а это в свою очередь ведет при частично когерентном поле в месте приема (в рассеивающих средах) к "уменьшению величины фазовой расстройки" (т.е. разности фаз) при не нулевых значениях пеленга (см. например, [2] с. 62). Это означает потерю пеленгационной чувствительности и появлении ее связи с состоянием канала распространения.The well-known steepness of the HR determining the direction-finding sensitivity (IF) of the direction finder,

From (2) and (1) the commonly used direction finding algorithm follows:

The desire to increase the range of phase direction finders leads to the need to increase the apertures of their antennas, and this, in turn, leads to a “decrease in phase mismatch" (i.e., phase difference) with non-zero at a partially coherent field at the receiving site (in scattering media) bearing values (see, for example, [2] p. 62). This means the loss of direction-finding sensitivity and the appearance of its connection with the state of the distribution channel.

 The appearance of a priori uncertainty in the IF and the use in this case in the algorithm (3) of the IF value (2), which is valid for coherent conditions, leads to a shift in the bearing estimate, i.e. to an error whose magnitude depends on the coherence of the field at the receiving location.

 The elimination of this drawback under the assumption of rotation (scanning) of the radiation pattern (ND) of the source is performed in the considered phase direction finder.

 To do this, a phase direction finder containing two antennas, each of which is connected through a receiver to the input of the phase meter, a divider, the first input of which is connected to the output of the phase meter, and the output of the divider is connected to the indicator, and an amplitude detector, a differentiator are introduced to the input terminal for the value of the steepness of the direction-finding characteristic. , a meter of angular velocity of scanning a radiation pattern of a source, second and third dividers, a device for module formation, a subtractor, a multiplier, a terminal for inputting a width of a radiation pattern of a source a nickname and an input terminal for the direction finder beam width, the output of one of the receivers through a series-connected amplitude detector and a meter of angular scanning speed of the source beam connected to the second input of the second divider, the first input of which through the differentiator is connected to the output of the phase meter, the output of the second divider through the device the formation of the module is connected to the first input of the multiplier, the second input of which is connected through the quadrator to the output of the third divider, the first the third input of the third divider is connected to the input terminal of the beam width of the source, the second input of the third divider is connected to the input terminal of the width of the direction finder, the second input of the first divider is connected to the output of the subtractor, the first input of which is connected to the output of the multiplier, and the second input of the subtractor is connected with the input terminal of the steepness value of the direction-finding characteristic. The drawing shows a structural electrical diagram of a phase direction finder.

 The phase direction finder contains two identical antennas 1 and 2, two receivers 3 and 4, a phase meter 5, an amplitude detector 6, a differentiator 7, a first divider 8, a meter 9 for the angular velocity of scanning the radiation pattern of the source, a second divider 10, indicator 11, a third divider 12, module formation device 13, subtractor 14, quadrator 15, multiplier 16, source radiation pattern width input terminal K1, direction finder width input terminal K2, direction finding steepness value input terminal K3 character Istics.

 To describe the operation of the direction finder, some explanation is necessary.

где μ пеленгационная чувствительность пеленгатора с учетом снижения когерентности поля в месте приема;
m_b крутизна изменения разности фаз, обусловленная сканированием диаграммы направленности источника и рассеянием на трассе;
q_и ширина ДН источника на уровне З дБ от максимума;
θ ширина ДН пеленгатора.It was possible to overcome a priori uncertainty in the steepness of the direction-finding characteristic in the direction finder under consideration by establishing and using its relationship with the additionally measured signal parameter of the steepness of the phase difference change due to scanning of the source beam and scattering along the path (see, for example, [1] p. 103, Fig. 6.6). As a result of using this parameter, it was obtained

where μ is the direction-finding sensitivity of the direction finder, taking into account the decrease in field coherence at the receiving site;
m _{b the} steepness of the change in phase difference due to scanning the source radiation pattern and scattering along the path;
q _{and the} width of the source beam at the level of 3 dB from the maximum;
θ width of the direction finder DN.

 The use of the sign of the module in (4) eliminates the dependence of the IF estimate on the direction of rotation of the source beam.

где b угловое положение ДН источника;
t время;
W угловая скорость сканирования ДН источника.The slope of the change in phase difference m _b in algorithm (4) is the angular equivalent of the slope of the change in phase difference in time. A practical measurement of m _{b is} made through the angular scanning speed of the source beam:

where b is the angular position of the source source;
t time;
W is the angular velocity of scanning the source beam.

Этот алгоритм и реализуется в рассматриваемом пеленгаторе.Having (4) and (5), the desired bearing estimation algorithm can be represented as follows:

This algorithm is implemented in the direction finder under consideration.

 Phase direction finder works as follows.

 The oscillations from the outputs of antennas 1 and 2 in the receivers 3 and 4 are amplified, if necessary they are converted and normalized to the form necessary for the operation of the phasemeter 5, and fed to its inputs.

 The signal from the output of one of the receivers is detected by an amplitude detector 6, at the output of which a packet envelope is formed, formed by scanning the source beam.

 The signal from the amplitude detector 6 in the meter 9 to determine the angular velocity of scanning the bottom of the source source Ω. Its determination can, for example, be carried out by measuring the period of review of the source DN by generating at the output of the meter 9 a signal proportional to W = 2π / T, where T is the measured value of the period of review.

The signal proportional to the phase difference from the output of the phasemeter 5 is fed to a differentiator 7, at the output of which the derivative dΔΦ / dt is formed, and after dividing it in the second divider 10 by the angular scanning speed Ω in accordance with (5), the output of the second divider 10 is formed the value of the slope of the phase difference m _b . The module of this value, which is formed at the output of the module formation device 13, is fed to the first input of the multiplier 16.

.The terminals K1 and K2 are connected to the inputs of the third divider 12 is inputted values, respectively, beam width of the source _and q and width direction finder patterns θ. The quotient of their division q _and / θ is squared in squared 15 and fed to the second input of the multiplier 16, where it is multiplied with the value of the slope modulus

.

In the subtractor 14, the value of the signal present at the output of the multiplier 16 is subtracted from the value of the steepness of the direction-finding characteristic (2) introduced at terminal K3: m _o = 2πd / λ, which is considered known. As a result, the value of the direction-finding sensitivity of the direction finder (μ) is formed at the output of the subtractor 14 in accordance with (4), taking into account the decrease in the coherence of the field at the receiving site.

 The division in the first divider 8, which is available at the output of the phasemeter 5, of the phase difference value by the direction-finding sensitivity μ existing at the current moment at the output of the subtractor 14 leads, according to algorithm (6), to form a bearing estimate displayed on the indicator 11 at the output of the divider 8.

 Thus, the implementation of algorithms (4) (6) in the phase direction finder under consideration allows us to increase the accuracy of direction finding of scanning sources on scattered paths by overcoming a priori uncertainty in direction-finding sensitivity by establishing and using its relationship with the additionally measured signal parameter of the steepness of the phase difference change due to scanning Source path and the presence of scattering on the path.

Literature
1. Sharygin G.S. The statistical structure of the VHF field over the horizon. M. Radio and Communications, 1983.

 2. Fortes VV The influence of the final dimensions of the antennas on the fluctuation characteristics of signals during the propagation of radio waves in the troposphere. - Radio engineering, 1987, N 12.

Claims (1)

 Phase direction finder of scanning sources, containing two antennas, each of which is connected through a receiver to the input of the phase meter, a divider, the first input of which is connected to the output of the phase meter, and the output of the divider is connected to the indicator, and a terminal for inputting the steepness value of the direction-finding characteristic, characterized in that introduced an amplitude detector, a differentiator, a measure of the angular velocity of scanning the radiation pattern of the source, second and third dividers, a device for the formation of the module, a subtractor, a multiplier, a terminal yes the source beam width values, the input terminal for the direction finder beam width and the quadrator, and the output of one of the receivers through a series-connected amplitude detector and a meter of the angular scanning speed of the source beam is connected to the second input of the second divider, the first input of which is connected through the differentiator to the output phase meter, the output of the second divider through the module education device is connected to the first input of the multiplier, the second input of which through a quadrator connected to the output of the third divider, the first input of the third divider is connected to the input terminal of the beam width of the source, the second input of the third divider is connected to the input terminal of the value of the width of the direction finder, the second input of the first divider is connected to the output of the subtractor, the first input of which is connected to the output of the multiplier, and the second input of the subtractor is connected to the input terminal of the value of the steepness of the direction-finding characteristic.