RU2566380C1 - System of astro-viewing - Google Patents

Abstract

FIELD: instrument engineering.

SUBSTANCE: unit of formation of astro-corrections is connected to the unit of sorting out of false astro-corrections, consisting of series-connected buffer of output signals of unit of formation of astro-corrections, two counters providing the signal sampling from the buffer, the differential system and the comparison system forming a threshold according to which the sorting out of false signals is carried out, the output of which is connected to the input of the unit of formation of the averaged value of astro-corrections. At that the unit of formation of the averaged value of astro-corrections is made with the ability to compare, providing sorting out of false astro-corrections on the threshold formed in the unit of sorting out of false astro-corrections.

EFFECT: increase in reliability.

4 dwg

Description

The invention relates to astroinertial navigation systems in which the basic navigation information (calculated coordinates and course) is adjusted according to the signals received from the output of the astroizing device.

Known astroinertial system described in RU 2442108 C1, 02/10/2012, consisting of astrovisir (teleblock) controlled by tracking systems that ensure its targeting to the calculated point by target designation issued from the onboard central computer, the output of which is connected to an analog-digital connected in series a converter, an astro corrections forming unit representing differences between the calculated and actual coordinates of the sighted star, and an averaged astro corrections generating unit. The disadvantage of this system is that in some cases, in contrast to the regular case of receipt of output signals, malfunctions (false signals) occur in the formation of output signals, which are a consequence of external factors during star sighting. Thus, the measurements contain the error caused by these failures.

The objective of the invention is to increase the accuracy of the measurements obtained by preliminary rejection of the indicated failures, with the achievement of such a technical result as improving the accuracy of determining the actual coordinates of a star by the astrovization system.

The claimed technical result is achieved by an astrovization system consisting of an astrovisor controlled by tracking systems that ensure its targeting at a design point by target designation issued from the onboard central computer (DAC), the output of which is connected to an analog-to-digital converter (ADC), the output of which is connected to block for the formation of astro corrections, representing the differences between the calculated and actual coordinates of the sighted star, the output of which is connected to the block for rejecting false a line corrections, consisting of series-connected buffer of the output signals of the astropod corrections forming unit, two counters that provide sampling of signals from the buffer, the difference system and the comparison system, which forms the threshold by which the fault signals are rejected, the output of which is connected to the input of the unit for generating the averaged astropod corrections, when this unit is the formation of the averaged value of astro corrections made with the possibility of comparison, providing the rejection of failed astro corrections by pore gu formed in the block of rejection of false astro corrections.

FIG. 1 is a graph reflecting the regular case of output signals in the form of angular corrections ΔA _i , ΔB _i in azimuth and altitude during the star sighting.

FIG. 2 is a graph reflecting failures (false signals) when generating output signals in the form of angular corrections ΔА _i , ΔВ _i in azimuth and altitude caused by external factors when sighting a star.

FIG. 3 - a well-known astrovization system.

FIG. 4 - the claimed system of astrovization.

The known astrovization system shown in FIG. 3, consists of an astrovisor (teleblock) 3, controlled by tracking systems 2, ensuring its guidance at a given point according to the target designation generated in the on-board digital computer 1, the output of which is connected to a series-connected analog-to-digital converter (ADC) 4, the unit for the formation of astro corrections 5, representing the differences between the calculated and actual coordinates of the sighted star, and the averaging unit of astro corrections 7.

The known astrovization system, the graph of the output signals during operation of which is reflected in FIG. 1, works as follows.

The output signals of the astroizing device, formed during the sighting of the selected star, are converted into a digital code in the analog signal conversion unit (ADC) 4, which is fed to the astro corrections forming unit 5, the output of which is an ordered sequence of digital signals, each of which represents the difference between the angular coordinates of the honey sighted star and their calculated values.

To form the measurement dA, dB in the averaging unit of astro corrections 7, the output signals are averaged:

where N is the number of output signals.

The averaged dB value is considered similar.

However, in some cases, in contrast to the regular case of the output signals presented in FIG. 1, there are failures in the formation of the output signals, as shown in FIG. 2. Moreover, such failures (false signals) are not associated with any hardware failures, but are a consequence of external factors when sighting a star. Naturally, in the presence of such failures, the measurement determined by (1) will contain the error generated by these failures.

In order to exclude failures (false signals) caused by external factors during star sighting, it is necessary to introduce a block into the system that allows you to sift (reject) such failures (false signals), i.e. block of rejection of false astro corrections 6.

To achieve the claimed technical result, the block of rejection of false astro corrections 6 is introduced into the system between the block of formation of astro corrections 5 and the averaging block 7 (Fig. 4).

The false astro corrections rejection unit 6 consists of a series-connected signal storage device coming from the output of the astro corrections formation unit, two counters identifying the numbers of the signals being compared, a difference system and a system for comparing the received difference with some fixed constant L, the value of which is determined by the accuracy characteristics of the system. In this case, the averaging unit 7 must be performed with the possibility of comparison, providing a selection of unreflected signals according to condition (4).

Block rejection of false astro corrections 6 works as follows.

The package of output signals ΔA obtained by sighting the selected star contains N output signals. To achieve the claimed technical result, the absolute values of the differences are calculated:

where i, j = 1, 2, ...; N is the number of the output signal.

. Среди вычисленных по (2) функций выбирается та, которая имеет максимальное значение, пусть это будет Abs(ΔA_s-ΔA_k), и аргументы ΔA_s, ΔA_k, входящие в состав этой функции, исключаются из дальнейшего рассмотрения - отбраковываются. Далее процедура отбраковки повторяется для всех неотбракованных выходных сигналов.Obviously, the number of such functions will be equal to the number of combinations $$C_N^{}$$$${}_2^{}$$

. Among the functions calculated by (2), one that has the maximum value is selected, let it be Abs (ΔA _s -ΔA _k ), and the arguments ΔA _s , ΔA _k that are part of this function are excluded from further consideration - they are rejected. The rejection procedure is then repeated for all non-rejected output signals.

The rejection procedure ends when one of the number of non-rejected output signals remains, in case the initial number N of signals is odd, since two signals are rejected in each rejection cycle, or two if the initial number of output signals is even. At the end of the rejection, a constant L is formed, which is equal to either the last non-rejected signal or the arithmetic average of the last two non-rejected signals, and then the averaged value is calculated:

where M is the number of all output signals that satisfy the condition:

Abs (ΔA _i -L) ≤L _p , (four)

where L _p is some predetermined threshold, the value of which is determined by the accuracy characteristics of the astrovization device.

Astroproof corrections in the form of a digital code coming from the output of the formation of astroproof corrections are stored in the signal storage registers M (k), the value MA (k) = True is generated in the corresponding register of the buffer of logical values MA (k) and the counter k is increased by one. When the value k = N is reached, where N is the number of astro corrections contained in the packet transmitted from the astro corrections forming unit, control is transferred to the threshold forming unit L.

The initial value of the counter is k = 0; boolean logical values - MA (i) = False.

The initial value of the counter N is set equal to the number of astro corrections contained in the registers of the signal storage device M (k). Counters i and j, changing as i = 1, 2, ...; N, j = i + 1, i + 2, ..., N, determine the numbers of the drive registers in which the signals are stored for calculating:

The value ΔM is calculated only for the ith and jth astro corrections provided that the i-th and j-th cells of the buffer of logical values of MA are set to True. The calculated ΔM value is compared in the comparison system to Am (the initial value Am = 0), and for ΔM> Am, the ΔM value is entered in Am, and the values of the counters I, j are stored in I ′, j ′. Thus, after viewing all pairs of drive registers (i = N), cells I ′, j ′ will contain the numbers of drive registers for which the difference ΔM is maximum. The value False is entered in the cells I ′, j ′ of the MA register, the counter N is reduced by two, Am is zeroed and the calculation operation ΔM according to the system described above is repeated until the counter N is less than three, i.e. of the number of measurements viewed, there will be two or one left, after which L is calculated by the following system:

The cells of the logical buffer AM are looked through and L is calculated as the value of M (r) of one remaining drive register for which MA (r) = True, or as the arithmetic mean of two values of the registers M (r) and M (s) for which MA (r) = True and MA (s) = True, and control is transferred to the execution of the averaging block, the system of which is shown in FIG. 7. In the averaging block it turns out:

the arithmetic mean of all astro measurements complying with the condition is calculated:

where L _p is some fixed threshold whose value is determined by the accuracy characteristics of astrovisir.

We show that averaging over (6) is completely equivalent to (1).

The proof is by induction.

Denote:

- arithmetic mean M terms.

Then by definition:

- arithmetic mean of M + 1 terms.

Selecting the last term on the right-hand side of (9), we represent (9) as:

We multiply and divide the first term on the right-hand side of (10) by M. Then, taking into account (8), we obtain:

Adding and subtracting one in the first term of the right-hand side of (11), we get:

those. received (6).

The initial value of the variable dA _m

dA ₀ = 0.

Upon receipt of the first signal ΔA ₁ according to (6) we obtain:

dA ₁ = dA ₀ + (ΔA ₁ -dA ₀ ) / 1 = ΔA ₁

Upon receipt of the second measurement ΔA ₂ we obtain by (6):

dA ₂ = dA ₁ + (ΔA ₂ -dA ₁ ) / 2 = (ΔA ₂ + ΔA ₁ ) / 2

and so on, which proves the equivalence of (1) and (6).

Thus, false signals caused by external factors during star sighting are cut off in the astrovization system, which makes it possible to increase the accuracy of determining the actual coordinates of a star by the astrovization system, and, accordingly, allows to more accurately determine the location of the aircraft.

The invention is practicable in high-precision astroinertial navigation systems for aircraft.

Claims (1)

An astrovization system, consisting of an astrovisor controlled by tracking systems that ensure its aiming at a calculated point by target designation issued from an onboard central computer (digital computer), the output of which is connected to an analog-to-digital converter (ADC), the output of which is connected to the astro-corrections forming unit, representing the differences between the calculated and actual coordinates of the observed star, the output of which is connected to the block of rejection of false astrophotographic corrections, consisting of sequentially with the dual output signal buffers of the astroproof correction unit, two counters that provide sampling of signals from the buffer, the difference system and the comparison system, which forms the threshold by which the fault signals are rejected, the output of which is connected to the input of the unit for the formation of the averaged astroproof value, while the averaged value generation unit astroproof corrections made with the possibility of comparison, providing the rejection of failed astroproperformations on the threshold formed in the block rejection of false tropopravok.

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