RU2631834C2 - Method and device for correcting characteristic nonlinearity of photoelectric direction-finder of electromagnetic energy distant source within reviewed straight angle - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: essence of the invention lies in replacing the linear signal scaling operation for the nonlinear one, received by the passive photodetector when the sensitive surface is irradiated by the radiant flux of a distant source. The method is reduced to calculating the relative dependence of the amplitude signal values of the "absolute" direction-finding characteristics of the photocurrent of the positional radiation detector with a semicylindrical sensitive surface and the synthesized nonlinear aperture characteristic of the photocurrents of the three radiation detectors, where one is with a planar sensitive surface, and two other positional radiation detectors are with semicylindrical sensitive surfaces. The last detectors are oriented by the sensitive surfaces in opposite directions, and the sensitive surface of the planar detector is orthogonal to it. The correcting device includes, at least, an analog-to-digital converter, three passive photoelectric detecting elements that, when irradiated by a stream of a distant source, generate photocurrents within the straight angle of the photoelectric direction-finder, and three current-voltage converters, two resistive voltage dividers, one adder, which is designed to form a synthesized signal necessary for the operation of the analog-to-digital converter with an external support, which acts SFA acts with the APDF simultaneously as a measurer of the nonlinear relationship between the two signals, and a voltage divider with a digital output, which allows to correct the output data when mismatching the angle of the optical axis of the measuring means with a distant energy center of the radiation source at the time of measuring the parts of the radiant flux guide by the measuring means.

EFFECT: determining the position of the distant source of electromagnetic energy within the reviewed straight angle in specific zones of the optical wave band.

4 cl, 6 dwg

Description

The invention relates to the field of aerospace instrumentation and relates to a way to improve the measuring tool for remote sensing positions of radiant flux sources - a static photoelectric direction finder (electromagnetic direction finder) of an electromagnetic energy source involved in solving problems of navigation, orientation, stabilization and position control of mobile aerospace objects in the solar energy center or other remote source of electromagnetic energy, tracking a landmark from the earth's surface and.

The tendency to improve TFP as a service measuring device of a mobile aerospace object today is to find ways to reduce the mass, volume and energy consumption while maintaining or improving metrological parameters, which allows you to increase the weight and volume of scientific or specialized equipment placed on an aerospace vehicle. In this regard, it is rational to find a method for correcting the non-linearity of the relative direction-finding characteristic of a device patented as RU 2526218 C1, 03/27/2013 and published on 08/20/2014. Other indicators correspond to the level of technological development for measuring instruments for remote sensing of positions of electromagnetic energy sources in near-Earth space, for tracking them from the ground.

The advantages of the patented invention RU 2526218 C1, 03/27/2013 — a device for determining the angular position of an electromagnetic energy source and a direction finder operation method — consists in an inventive approach to constructing an SFP with respect to the level of technology development, in new methods and actions with detecting elements of a measuring device and their interconnection, which made it possible on this basis to improve the limiting parameters of remote sensing means of the position of electromagnetic energy sources in the optical wavelength range .

Recall that the essence of the method of constructing the patented device RU 2526218, 03/27/2013 is to use radiation detectors with a semi-cylindrical sensitive surface with their opposite orientation to determine the position of the radiant flux and a rational combination of the work of two interconnected converting electronic links: functional and linear. The photoelectronic component of the device’s functional link includes three active radiation detectors with semi-cylindrical sensitive surfaces, one of which is oppositely oriented with respect to the other two, and the electronic link consists of a minimal set of local electronic linear elements - two current-voltage converters, one analog-to- figure ", which are necessary for the device to obtain the results of the angular position of a remote source of electromagnetic energy in figures howl form. In this embodiment, the construction of the device “absolute” and “relative” direction-finding characteristics in the measuring tool are similar, since the “nominal scale factor” does not introduce distortions in determining the ratio.

The approach and actions in the patented device RU 2526218, 03/27/2013 are reduced to the fact that a passive single radiation detector with a semi-cylindrical sensitive surface, which is oriented with its optical axis along the angular axis of the rectangular coordinate system of the device, sets an odd-symmetric "absolute" direction-finding characteristic corresponding to sine law within plus / minus 90 °, shifted along the ordinate axis - the optical axis of the TFP, when the amplitude energy axis of the radiation detector divides the characteristic of the sensor along the angular axis in half: the right side is the positive direction and the left side is the negative direction. Moreover, the overview “relative” direction-finding characteristic of the TFP corresponds to the sine law only within the angular survey sector plus / minus 90 °, if the device is rigidly fixed on the fundamental landing plane of the aerospace vehicle with an area an order of magnitude larger than the base of the device.

However, the device and method, taken as the starting point in the invention patented below, is characterized by a small sector window - plus / minus 45 ° of the linear part of the direction-finding characteristic of the TFP within the relative angular error of plus / minus 2%. This is a disadvantage, since it limits the potential use of the measuring tool on the aerospace vehicle, but it can be overcome if the direction-finding characteristic of the TFP is corrected within the sweep angle.

The fact is that, based on the “task / solution” principle, the device consists of basic functional elements that are necessary for correcting the non-linearity of the relative direction-finding characteristic, but they are not fully involved, performing only a neutral linear operation - converting “absolute” to “relative” »Measuring the position of the radiant source. Without the use of additional elements, it is impossible to correct the effects on the initial characteristic, which is determined in TFP by a single detecting element with a semi-cylindrical sensitive surface.

Patented “Method and device for non-linearity correction of the characteristics of the photoelectric direction finder of a remote source of electromagnetic energy within the sweep angle” (hereinafter - “Correction method ...”, “Correction device ...”) are allowed to solve besides the direction finding problem due to component redundancy with respect to the basic structure of the prototype reference point, the question of correcting the initial non-linearity of the overview characteristic of the direction finder, expanding the scope of the TFP as a measuring angular tool.

The technical result is achieved by supplementing the original device with typical electronic components: two “passive” and two “active” elements, on the same basic structure of the TFP, the problem of creating a measuring instrument that determines the position of a distant source of electromagnetic energy within a sweep of an unfolded angle working in specific zones of the optical wavelength range, which are determined by the spectral characteristics of radiation detectors, with a relative error of rhenium angular source position plus / minus 2.3%.

The essence of the “Correction Method ...” lies in the formation of the relative direction-finding characteristic of the TFP with an analog-to-digital converter (ADC) with an external “support”, the inputs of which are supplied with two signals — a “positional” voltage whose current amplitudes correspond to the functional dependence of the photocurrent of a passive radiation detector generated when a distant source is incident on the radiant flux and the “non-linear scale factor” - the sum of the signals received by three differently oriented detectors radiation targets within the surveyed unfolded angle of the direction finder.

In order to realize the advantages and substantiate the qualitatively inventive step of the patented invention, we will consider the electrical functional construction of the correction device visualized below, the aperture and direction-finding characteristics of the TFP, we will provide some explanations and comments on them.

In FIG. 1 is a diagram of an electrical functional TFP that implements a method for correcting non-linearity of a direction-finding characteristic.

FIG. 2 shows the “two-dimensional” aperture and direction-finding characteristics at the points indicated on the electric functional TFP diagram.

In FIG. 3, the 3D direction finding characteristic of one TFP channel is visualized, in which the correction of the nonlinearity of the direction finding characteristic is implemented within the overview developed angle of the device.

Fig. 4 shows the relative position of two TFP channels in a “three-dimensional” representation, one of which is “mirror”.

FIG. 5 shows a general view of the design of a “biaxial” TFP.

In FIG. 6 shows the bearing characteristics of the TFP, which it has along each of the two axes in a rectangular coordinate system of a mobile aerospace vehicle.

The general expression for the photocurrents of radiation detectors used in TFPs is defined as:

where E _e - irradiation, W / m;

A is the parametric factor of the detector, which is equal to - J * S * L * D * m;

J is the quantum efficiency of the detector;

S is the value of the steepness of the radiation detector with a normal incidence of the radiant flux of the separated source, A / W;

L is the length of the sensitive surface of the radiation detector, m;

D is the width of the sensitive surface of the radiation detector, m;

m is the coefficient of equivalence of the shape of the sensitive surface of the radiation detector with respect to the planar version taken per unit;

ƒ _n (α) and ƒ _n (β) are functions of radiation intensities in the angular coordinates of azimuth and location;

n is the radiation detector number in FIG. one;

* - sign of the work.

We note the following points.

The axes of the construction (metric) rectangular coordinate system of the TFP are collinear to the angular axes of the rectangular coordinate system of the mobile aerospace vehicle. The length of the detector is parallel to the azimuth axis, and the width is the axis of the place in the rectangular angular coordinate system of the mobile aerospace object, where for the planar radiation detector ƒ (α) is cos (α) and ƒ (β) is cos (β), and for the detector with a semi-cylindrical sensitive surface m = 0.637, ƒ (α) - [1-sin (α)] and ƒ (β) - cos (β). For TFP design, it is preferable that L = D.

Until 2013, the determination of the angular position of the radiation source based on the direction-finding characteristic in one measurement plane was obtained by the DELTA / SIGMA method (RU 2399063 C1, December 16, 2008), when the difference was determined in the numerator by synthesizing (combining) and the ratio was formed in the denominator the sum of the signals by two photodetectors with planar sensitive surfaces oriented in opposite directions to a fixed angle (direction-finding characteristic) relative to the optical axis of the TFP. The disadvantage of this method is the sector window, in the absence of mutual shading of the sensitive surfaces of the radiation detectors, is plus / minus 45 °, and the relative error of the window of the direction-finding characteristic of the TFP is plus / minus 2%.

The “DELTA / SIGMA” method in RU 2526218 C1, 03/27/2013 showed the same error in the measurement results in the plus / minus 45 ° window, where radiation detectors with semi-cylindrical sensitive surfaces were used in the TFP, but the measuring sector had a plus / minus 90 ° , and the relative error of the sweep angle was within plus / minus 11%. The indicated drawback is eliminated if the nonlinearity of the characteristics of the unfolded viewing angle of the TFP is corrected.

The main distinguishing feature of the TFP (RU 2526218 C1, 03/27/2013) is the sum of the signals in the ratio denominator obtained by combining the photocurrents of two radiation detectors with semi-cylindrical sensitive surfaces, always corresponds to a constant nominal value within the panoramic sweep of the TFP. From here it becomes clear how to correct the nonlinearity of the overview direction-finding characteristic of the device without changing the basic structure of the TFP.

The condition for correction in this case is obvious - it is necessary that the amplitude value of the signal of the ratio denominator at the unambiguous points of the unfolded viewing angle of the TFP be greater than the amplitude of the signal in the numerator at the time of registration of the photocurrents of the radiation detectors. In practice, it is feasible within the framework of the basic structure if one more radiation detector with a planar sensitive surface is added to the TFP. Then, so that the operation of combining the photocurrents of the radiation detectors corresponds to the linear regularity of summation, the orthogonal orientation of the planar radiation detector with respect to the optical axes of the radiation detectors with semi-cylindrical sensitive surfaces is preferable.

The result of the analysis - a new method for correcting the nonlinearity of the direction-finding characteristic of the TFP is patented, which through the ratio of the amplitude values of the signal magnitudes of the “absolute” direction-finding characteristic of the photocurrent of one “positional” radiation detector and the synthesized aperture characteristic of the photocurrents of three radiation detectors, where one has a planar sensitive surface and two other radiation detectors, as in patent RU 2526218 C1, 03/27/2013 with semi-cylindrical sensitive surfaces, allows improving metrological characteristics measuring means within the surveillance straight angle.

The electrical functional diagram of such a TFP is depicted in FIG. one.

The work of the TFP with a device that corrects the nonlinearity of the survey sweep angle, in the patented invention is described as follows.

When the radiant flux of a distant source incident on the TFP at the output of the “positional” radiation detector 1 (Fig. 1) has a semi-cylindrical sensitive surface, the optical axis of which is oriented along one of the axes of the rectangular coordinate system of the mobile aerospace vehicle, and operates in the “short circuit, a photocurrent is generated.

The linear angular characteristic of the unfolded overview angle of the TFP is shown in FIG. 2 as ƒ 0, and the “two-dimensional” aperture characteristic of the “positional” radiation detector 1 in FIG. 1 is visualized in FIG. 2 as ƒ 1.

After converting the photocurrent of the radiation detector 1 (Fig. 1) to voltage using a current-voltage linear converter 4, the latter enters the "positional" input (9) of the analog-to-digital linear converter 7 with an "external support".

Correction device - a hybrid association in the TFP. Based on FIG. 1 contains:

- three passive photoelectric detecting elements 1-3, which, while irradiating with a flux of a distant source, generate photocurrents within the developed angle of the direction finder;

- “current-voltage” converters 4, 5, 6 — linear elements designed to interface the photocurrents of radiation detectors with ADCs;

- two resistive voltage dividers R4, R5, R6, R7 - passive elements that determine the magnitude of the correction of nonlinearity in the characteristic sections of the unfolded viewing angle of the TFP;

- one linear adder 8, designed to generate a functional signal - “non-linear scale factor” 12, necessary for the operation of the analog-to-digital converter 7 with an external support, which acts in the TFP at the same time as a measurer of the relations of two functional signals 9, 12 and a voltage divider with digital output 13, which allows you to adjust the dependence of the value of the output signal when the optical axis of the sensor is mismatched with the energy center of a remote radiation source at the time of measuring the sensor icom parts of radiant stream landmark.

It is characteristic that the sensitive surface of the radiation detector 2 is different - planar. This is the first difference between the photo of detector 2 in front of radiation detectors 1, 3, and the second is the orientation of the optical axis of the detector, which is orthogonal to them along the angular axis α in the rectangular coordinate system of the mobile aerospace vehicle. In addition, radiation detectors 1, 3 with semi-cylindrical surfaces look in opposite directions along the α axis. The aperture characteristic of radiation detector 2 is shown in FIG. 2 as ƒ 2, and radiation detector 3 - ƒ 3.

Based on the formula (1), the expressions for the photocurrents of radiation detectors 1-3, shown in FIG. 1, imagine how:

Guided by the fact that the current-voltage converters 4-6, passive voltage dividers R4-R7, the adder 8 and the ADC - 7 are linear electronic components of the TFP, we express the signal - "non-linear scale factor" - at point 12 in FIG. 1 through the synthesized (combined) current I _Σ (α, β):

I _Σ (α, β) = I ₁ (α, β) * k ₁ + I ₂ (α, β) * k ₂ + I ₃ (α, β) * k ₃ = 0.637 * E _e * A * cos ( β) * {[1-sin (α)] + 1.57 * cos (α) * k ₂ + [1-sin (-α)] * k ₃ },

Where

In this case, the expression for the corrected direction-finding characteristic of the panoramic unfolded angle of the TFP looks like:

In FIG. Figure 2 shows the “two-dimensional” normalized signal curve — the “nonlinear scale factor” ƒ 12, constructed at k ₂ = 0.41 and k ₃ = 0.18.

FIG. 3 visualizes a 3D image of the adjusted overview direction-finding characteristic of the TFP at the ADC output at point 13, shown relative to the plane at the level of 0.5 (corresponds to the highest level) and constructed at k ₂ = 0.41 and k ₃ = 0.18. It demonstrates that variations in the radiant flux along the β axis within the sweep angle are brought to the nominal value by the ADC and do not affect the measurement results along the angular axis α within the rectangular coordinate system of the mobile aerospace vehicle.

It should be noted that for small mobile aerospace vehicles, preferably a modified construction of the TFP is an option with mirror channels and corrected panoramic direction-finding characteristics.

In FIG. 4 shows in a “three-dimensional” measurement the relative position of the direction-finding characteristics of two TFP channels, which are mirrored with respect to each other. Replenishing the elemental composition with another current-voltage converter and ADC, we obtain the results of changes in the position of the radiant source (landmark) by uniaxial TFP over two channels. Such an elementary set of TFP realizes simultaneously the measurement results, which are opposite in angular values, relative to the senior bits of the two ADCs involved in the direction finding process.

Hot redundancy of measurement results, doubled angular resolution within the sweep angle of the device, determination of lateral interference (flare) are the hallmarks of the two-channel version of the construction of a uniaxial TFP.

The expression for the corrected direction-finding characteristic of the surveyed unfolded angle of the TFP with the “mirror” channel looks like this:

The functional electric circuit of the formation of the TFP with the “mirror” channel is similar to the single-channel uniaxial version, except that the voltage of the signals of the radiation detectors 1 and 3 at the outputs of the current-voltage converters goes to the “mirror” channel as indicated in brackets (3 ) and (1) in FIG. one.

Adding two passive radiation detectors with semi-cylindrical sensitive surfaces, which are orthogonally oriented with respect to two basic detectors, having four corrective links in the TFP, which determine the non-linearities of the unfolded orthogonally oriented angles, we obtain a passive measuring tool for remote sensing of the position of the electromagnetic energy source with a working window 180 ° × 180 °.

The design of a monoblock version of building a “biaxial” TFP with four output digital channels is presented in FIG. 5, where 14-17 are lateral radiation detectors with semi-cylindrical surfaces having a radius R, 18 is a radiation detector with a planar sensitive surface, the dimensions of which are L and N. The orientation of the sensitive surfaces of the TFP radiation detectors relative to the α and β axes in a rectangular coordinate system of a mobile aerospace the apparatus is visible from FIG. 5 and does not require explanation. The overall dimensions of the monoblock “biaxial” TFP are determined by the L and H sensitive surfaces of the planar radiation detector. The orthogonal direction-finding characteristics of the TFP along the axes α - ƒ 13 and β - ƒ 15 are visualized in FIG. 6.

The technical advantages achieved with the patented “Correction Method ...” and “Correction Device ...” are characterized by the following preferred features that justify the quality - inventive step - of a new measuring tool.

1. In the part "Method of correction ...":

- the use in TFP of an additional detecting element with a planar sensitive surface, necessary for the formation of aperture characteristic signals - “non-linear scale factor”;

- orientation and fixation of the sensitive surface of the additional detecting element in the TFP perpendicular to its optical axis and orthogonal to the optical axes of the radiation detectors with a semi-cylindrical sensitive surface;

- synthesizing (combining) using the correcting signal adder - “non-linear scale factor” - of three components: two voltages received by radiation detectors with semi-cylindrical sensitive surfaces, and one voltage of the detecting element with a planar sensitive surface.

In the part “Correction device ...”:

- additional detecting element;

- at least two resistive voltage dividers;

- at least one adder synthesizing the correction signal is a “nonlinear scale factor”.

Claims (4)

1. A method for correcting the non-linearity of the characteristics of a photoelectric direction finder located on a mobile aerospace object, a remote source of electromagnetic energy, which is a reference point within the sweep angle, which consists in the use of the formation of the relative direction-finding characteristic of the photoelectric direction finder voltage amplitudes of radiation detectors with a semi-cylindrical sensitive surface one set, correlate the signals with the amplitudes of the union n of strains representing the “nominal scale factor”, which are obtained by radiation detectors with a semicylindrical sensitive surface of another set with the opposite axes of the radiation axes of the two sets of radiation detectors in the angular rectangular coordinate system of a mobile aerospace object, characterized in that they use the voltage amplitudes of the combined signal, which represents nonlinear scale factor "as a corrective effect on the shape of the direction finder characteristics in the banner Thereafter, the relations of the two sets synthesize for this a “non-linear scale factor” from the sum of the voltage amplitudes of not two, but three radiation detectors, for which they complement the direction finder with a radiation detector with a planar sensitive surface, define the rectangular shape of the sensitive surface of the planar radiation detector, orient the opposite sides of the radiation detector parallel to the coordinate axes of the mobile object, and a planar sensitive surface to the optical axes of the radiation detectors with a semi-cylindrical the sensitive surface, radiation detectors are positioned so that the sensitive surfaces do not obscure each other within the sweep angle of the photoelectric direction finder, convert the photocurrents that simultaneously occur when the radiation detectors are irradiated with a radiant landmark stream, using three current-to-voltage converters, they supply "The signal from the output of one current-voltage converter to the input of the analog-to-digital converter, and the output signals of two other current-to-current converters - voltage "- to the resistive dividers, the parts of which are fed to the adder, they receive a synthesized signal representing the" non-linear scale factor "at the output of the adder, a synthesized signal is fed to the input" external support "of the analog-to-digital converter, and this is obtained at the output an analog-to-digital converter in the form of a ratio of the input amplitudes of two signals; results that describe the position of a distant radiant landmark using direction-finding characteristic codes corrected in an analog-to-digital converter pa »at each particular discrete point of the surveyed unfolded angle of the photoelectric direction finder. 2. The method according to p. 1, characterized in that they also supplement the photoelectric direction finder with current-voltage and analog-to-digital converters, use the unused photo current of the radiation detector with the opposite orientation of the initial set, as well as the synthesized signal from the output of the adder, form additional the converters the second direction-finding characteristic of the photoelectric direction finder, for this purpose a signal is supplied from the second radiation detector of the initial set to the input of the additional current-to-voltage converter ”, and its output voltage and the synthesized signal from the adder’s output go to the inputs of an additional analog-to-digital converter according to an electric circuit similar to that for the primary radiation detector, they receive the results of the radiant landmark position in the form of an inverse code — the value of the mirror direction-finding characteristic of the photoelectric direction finder. 3. A device for correcting the non-linearity of the characteristics of a photoelectric direction finder located on a mobile aerospace object, a remote source of electromagnetic energy, which is a reference point, where four radiation detectors, which, when irradiated with a stream of electromagnetic energy from a distant source, generate photocurrents within the viewing expanded angle of the photoelectric direction finder, characterized in that at least there are three current-voltage converters connected at the inputs with three parts radiation outlets of four, two resistor voltage dividers connected to the outputs of two current-voltage converters of three that are electrically switched with the adder, and its output is connected to the external support input of the analog-to-digital converter, while the output of the third the current-voltage transducer is connected to the “positional” input of one analog-to-digital transducer, which simultaneously acts as a meter for the ratio of two signals that determines the angle of mismatch of the optical axis of the photoelectric direction finder with the energy center of a remote source of electromagnetic energy at the time the photoelectric direction finder measures the radiant landmark flux. 4. The device according to claim 3, characterized in that there are four radiation detectors with a semi-cylindrical sensitive surface, which, when irradiated with a stream of a distant source, simultaneously generate photocurrents within the developed angle of the photoelectric direction finder, four current-voltage converters, two resistive voltage dividers , an adder and two analog-to-digital converters with switched inputs, so that the two outputs of the analog-to-digital converters have corrected digital res ultaty of two direction-finding characteristics mirroring to each other of the survey expanded angle of the photoelectric direction finder.

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