SU892210A1 - Theodolite code dial and device for decoding limb readings - Google Patents

Description

one

The invention relates to angular geodetic measurements, namely, actomatized systems for measuring vertical and horizontal angles on the ground, using theodolites with code limbs.

Systems of code theodolites are known, differing in the code used, the equipment for reading and recording samples, and their decoding. Among the code limbs used in theodolites, we can distinguish limbs for the so-called pulse counting, carried out in two (stages: rough and precise counting 1.

Theodolite code limb is known, which is a transparent disk with concentric dashed paths, on one of the KOTOEWX, an accurate reference track, strokes are applied evenly around the entire circumference. To determine the number of the stroke, there are tracks of exact count, and therefore for rough counting, additional tracks are provided, the strokes of which are vertically offset from the strokes of the track of exact count 2 and 3.

To increase the accuracy of reading, it is necessary to increase the number of strokes of the track of the exact reference and to increase the number of auxiliary ones that are more expensive than 1G coarse reference. This is fraught with considerable technological difficulties in the manufacture of a limb and the installation of the entire theodolite system, on the one hand, and the complexity of developing a sample decoding device that ensures the elimination of the ambiguity error of a rough count.

A device for decoding samples is known, designed for a theodolite code limb and adapted for a limb with one coarse count track 4.

However, the known device cannot be implemented for improved code limbs without noticeable complication.

20

The purpose of the invention is to eliminate the ambiguity error of a rough readout without increasing the requirements for the accuracy of manufacturing and assembling the code limb.

25

To achieve this goal, only two coarse reference code tracks are provided on the code disk, the strokes of one of which are offset from the strokes of the track.

30 exact countdowns, conditionally divided

several ranges with an equal number of strokes in each, vertically within each range, and strokes of the other coarse track are shifted relative to the strokes of one of the two other tracks by an angle that is constant within each range but varies from range to range.

To ensure reliable elimination of gross read ambiguity errors, a decoding device containing a scanning unit with a sensing diaphragm and a reference sensor, as well as a logic circuit with discriminators of the signal sequence and coarse and fine counting counters, made up of three AND elements, a trigger and control counter, and scale dividers clocks, the outputs of which are connected to the inputs of the respective counters, and the inputs through the keys are connected to the sensor input clock and the pulses and the first input of the element I of the correction unit by the first inputs of the keys are used by the first outputs of the discriminators of the sequence of the signal by the second inputs of the keys, and one of the inputs of the discriminator of the range signal is connected to the subband sensor of the ranging signal, and the second input is connected to the first input of the element is And, the second trigger is connected with one of the inputs of the element And, the second input of which through the control counter and the second input of the element and 2 is connected to the second output of the discriminator exactly and under the band signal, and the output of the AND element are connected through a resolution input circuit with a range counter, the reset bus of which is connected to the reset bus of the scale dividers for the range sample and the second discriminator output of the range and subband samples.

In addition, the reading diaphragm in the decoder: made in the form of three slits, two of which are located on the same straight line, and a third is shifted relative to them by a distance equal to half the discreteness of the coarse reference.

on. FIG. 1 shows the code limb; in fig. 2 is a functional diagram of a decoding device; in fig. 3: options for arriving at the photosensors of information signals during scanning; in fig. 4 - scanning diaphragm; in fig. 5 is an example of counting.

The code limb is a transparent circle 1 with three concentrically applied dashed lines of exact counting 2, subband counting 3 and span counting 4. The strokes of exact track 2 are applied across the limb evenly at equal angular intervals. The limb is conventionally divided into N ranges, each of which contains an equal number of strokes of the exact track. Each range in turn is divided into K equal subranges. The angular value of one subrange is equal to the size of the scanning window and is 400} HK The strokes of the second track 3 are offset relative to the corresponding strokes of the first track in the direction of increasing the sequence number of the strokes of the first track (according to the clockwise vernius in each of the ranges). The interval between the respective strokes of the first and second tracks determines the sequence number of the strokes of the first track within one of any ranges. The strokes of the third code track 4 are shifted relative to the corresponding strokes of the second road 3 in the opposite direction so that within each range the interval is not kept constant, but changes according to the vernier law with a change in the range number.

When you hover the theodolite at the point of sight, in the scan window there appear strokes, one on each track (with the exception of some cases discussed below), carrying information about the measured angle value.

Information processing is carried out in a sample decoding device comprising a scanning unit, including photosensors of ticks 5, exact counting b, subband counting 7 / range counting 8, and a logic unit consisting of a discriminator 9 of a sequence of fine and subband samples, discriminator 10 of a sequence sub-band and band. counts, counters 11, 12 and 13, block 14 of the amendments to the decoder 15.

Channel accurate calculation also contains the trigger 16, recording the arrival of an accurate information line, and the key 17.

The discriminator 9 of the sequence of the exact and sub-band signal consists of trigger 18 and a matching circuit 19. The discriminator 10 of the range and subband loop sequence consists of trigger 20 and a matching circuit 21. In addition to counter 12, a subband reference channel contains a key 22 and a scale divider 23. A range reference channel consists of a key 24, a scale divider 25, a counter 13, and an amendment resolution circuit 26. The correction unit 14 includes a trigger 27, a control counter 28 and elements C, 29, 30 and 31. When scanning an image of a section of a limb, the instant of coincidence of the scanning diaphragm with the information bar is recorded photometrically. Simultaneously with the image of the limb area, the tact track t is scanned, which is a ruler with alternating transparent and non-transparent intervals. The relative position of the strokes and the distance between them determines the count. The scanned area can be represented either as a frame of film in the case when photo registration of the code theodolite is performed with further processing on a standalone decoder, or as an image of a section of a limb in a plane suitable for scanning. In the latter case, the decoder can be placed in the case of the theodolite, the count can be reproduced on the scoreboard directly in the measurement process. FIG. Figure 3 shows possible options for the arrival of information and clock signals on the photosensors during the scanning process of the image of a section of a limb or frame. When scanning, the signals from tracks 2, 3, 4 and t enter the decoder device respectively at sensors 5-8, are processed in a logic unit and through a decoder 15 arrive at a digital display (not shown), which displays the score in hail, centigrade and centi-grades. Full count is equal to B D + P + T, where D - range count; P - subrange reading; T - accurate countdown. The exact count (fractions of hail) is determined by the number of clock intervals placed on track 2 from the information pulse along the read line (segment A in Fig. Over, b) In the decoder, this segment corresponds to the number of pulses coming from the sensor 5 cycles to the counter 11. Precise readout. Key 17 opens with trigger 16 when a signal arrives at precision readout sensor 6. Precise readout is equal to T "Ji P, 400 00 00 where. To -L dividing the scaling scale, .scards, L is the number of tacts placed in the scanned window P - the number of tact o and The pulses are taken as the sum of the range and subband samples. To obtain the range and subband samples, clock pulses are used coming from the sensor 5 clock pulses and recalculated using large-scale dividers 23 and 25, standing before counters 12 and 13. Coefficients divisions of the scale dividers X and Xn increase the clock resolution for band and subband tracks. The values of K, N, L, X, Chl are chosen from the condition that the discreteness of clock cycles for the range and subband samples be greater than the error in the relative position of the information signals on these tracks. The error is random and depends on the accuracy of manufacture, assembly and adjustment of the instrument. In the model of the proposed device, K N 20 was selected, the size of the window being scanned was gr---- 1, the number of clocks of the clock scale L 1000, the scale factors X Hp LL 1000 with "", - ;: - :: - - oK - 50. Thus, the MC M 20 times, the discreteness of the clock count for the band and sub-band tracks is the same and is fifty cycles of the exact count. Scanning slit should be made so that when reading electrical signals from tracks 2 and 3 the shift is 1/2 the subband reference resolution, and when reading signals from tracks 3 and 4 (or from 2 and 4, if the limb shifts between dashes tracks 2 and 4) on 1/2 discreteness of a range reference. For the same sampling resolution for band and subband counts and on the limb, the strokes of track 4 are displaced relative to the strokes of the second track, and the scanning diaphragm is made in the form of three slits (Fig. 5), each of which corresponds to a specific code track: 32 — track 2 of exact count, - 33 - track 3 of sub-range counting, 34 - track 4 of the range counting. The slit 32 is shifted relative to the slits 32 and 34 by an U value equal to 1/2 the discreteness of the coarse reference, in the direction opposite to the direction of increasing the sequence number of the strokes of the exact track. The range count, corresponding to the number of ranges in which the scan window is located, is determined by the relative position of the strokes along tracks P and W and the number of whole cycles of the range count placed in sections B and C (FIG. 3A) or E (FIG. 36). The count from sections B and C is taken in the event that the first signal from the sub-band count track arrives on the scanner unit, and the second signal from the band count track. The counting E is taken in the case of the inverse sequence of strokes and is performed as follows. In the decoding device, the trigger 20 is initially set to such a position that the key 24 is open for clock pulses, which through the scale divider 25 arrive at the counter of the range count 13. Upon arrival at the sensor 8 of the signal of the band track via the key 24 n the counter 13 and the scale divider 25 arrive the reset pulse, the position trigger 20 does not change, so the counting starts again from zero until the signal from the subrange-count track arrives at sensor 7. At this time, the trigger 20 closes the key 24 and the count is terminated. If the first impulse comes from the sensor., Then the trigger 20 closes the key 24, the counting stops before the pulse arrives from the sensor 8, the counting is resumed and continues until the end of the scan (to the edge of the scan line or the end of the frame). Range count is. where d --- is the cost of dividing the time scale of the range reference; t is the number of clocks of the clock scale of the exact counting, stored in the indicated areas; X. - scale factor range response. (The part of the division is taken into account. The sub-band count corresponding to the sub-band number in the range is determined by the number of tact-sub-band count placed on sections A and B (FIG. 3A) silt on section A (FIG. 3B) depending on the relative position of the bars. If the scanner is the first to go to the signal from the subband sample sensor 7, and then from the precision sample sensor 6, then the sample is taken over sections A and B. In the case of a reverse sequence of signals, the sample is taken over section G. the signal discriminator 9 serves as the signal from trigger 18 and the coincidence circuit 19. In the initial position, trigger 18 opens the key 22, skipping clock signal of the subband reading clock (via the scale divider 23). With arrival of the signal from sensor 7, trigger 18 closes key 22 and the counting stops before the signal from sensor 6 returns the trigger to its original position, key 17 opens again and the count continues until the end of the scan. When the sequence of arrival of signals is reversed, trigger 18 remains in its initial position with the arrival of a pulse from sensor b. . The subband count is equal to Pn--,, 400 i where Lp m7k is the price of dividing the cycles of the subband counting; T is the number of accurate read cycles stacked on the indicated areas; Xf is the scaling factor for subband reading. (The whole part of the division is taken into account). The total count is 400 m with 4-LNK Xj L: FIG. 5 shows a specific example of counting, the number of ticks of the exact scale that fit in the indicated areas n, t, t are 625, 75, 125, respectively. At L 1000, K N 20, H. Ho. 50, the width of the reference window by the formula we get., GO 75. 125 B - 625 20 + 2 + 20 - 20. 1000 + 6225 22. - (The fractional parts of the components constituting the coarse count are discarded). When going from band to band, when two signals appear in the scan window, a mandrel is required on the sub-sample track (Fig. 3 Sv) + 1 to the band count. The subpath track ignores the signal from the exact track for the value that is half the cycle of a single-batch reference (section F in Fig. 3 Sv). If the error is

Because of the inaccuracy of drawing strokes and the instrumental error of the instrument in the amount not exceeding this value, there will be no error due to the ambiguity of the reference. In the model of the proposed device, the error from the indicated reasons was xOZ, which is three clock cycles of exact counting. On the other hand, the discreteness of clock cycles of subband reference is equal to five times the clock cycle of exact counting. Consequently, such an error does not introduce an error. The same applies to range reading.

The magnitude of the region F (Fig. Sv) is determined by the number of precision clock ticks stacked in this interval. The key 30 of the block 14 amendments in the initial position is closed. With the arrival of the signal in the subband sample track, element 30 is opened by trigger 18 and passes clock pulses to control counter 28. With the arrival of a signal on the reference track, trigger 18 closes element 30 and the count stops.

If the count value on the control counter 28 is equal to the number of clock cycles, which is half the sampled subband count, then the correction input signal 26 sends the enable signal through element 31 and after the scan (reading line 35 in FIG. 3) completes the correction, the correction enters the range block countdown.

Correction is required in all cases of transition from a range to a range if there are two signals along a subband count track during scanning, except when moving from the last range to zero (Fig. 3g). The image of this frame differs from the previous one by the time of arrival of the signals. by range and accurate tracks during scanning. The coincidence of the signals is fixed on the trigger 27, where the signal from the element 29 arrives. The trigger 27 closes the circuit 26 and the correction is not made

When testing the layout and prototype of a theodolite with a code disk and a decoding device, the elimination of an ambiguity error in the final reading was confirmed. The creation of such a theodolite is not associated with significant economic costs and will provide a significant economic effect.

Claims (4)

1. The theodolite code limb, which is a transparent disk with concentric dashed paths, one of which, the exact counting track, strokes evenly around the entire circumference, and the other coarse tracks show offset lines to indicate the exact stroke number of the exact track. of reference, characterized in that, for the purpose of Waneni's errors, there is a coarse read ambiguity without increasing requirements, to the accuracy of manufacturing and assembling r there are only two coarse reference code tracks, str and one of which is offset relative to the track grooves precise reference conditionally divided into several bands with an equal number 0 strokes in each, nonius within each range, and strokes of the other coarse track are offset relative to the strokes of one of the two other tracks by an angle c Within each range, but varying by the vernier law from range to range. 2. A device for decoding samples by code limb in p. E, containing a scanning unit with a reading diaphragm and reference sensors on dashed and clock tracks, as well as a logic circuit with discriminators of a signal sequence coarse and accurate readout counters, characterized in that, in order to reliably eliminate the coarse read ambiguity error, the correction block on the three elements And, the trigger and the control counter and large-scale clock dividers, the outputs of which are connected to the inputs of counters of one exact and two coarse, band and subband samples, and inputs through keys with the output of a pulse sensor from the clock track and the first input of one of the elements AND of the correction block by the first inputs, and with the first outputs of the discriminators on the second inputs of the keys, and the inputs of the discriminators of the sequences of signals of a rough count are connected respectively to the sensors of the range and sub-band counting, and also with the first input of the second element And, the second input of which is connected to the precision reference sensor, and the output through the trigger to one of the inputs of the third element And, the other input of which is connected through the control center: eTechik and the second input of the secondI element And with the second output of the discriminator of the exact signal sequence and subrange samples, and the output with a range count counter through the correction input resolution circuit, while the reset bus of the range count counter is interlocked with the reset bus of the scale divider The leg frame and the second output of the discriminator coarse reference signal sequences. 3. Device according to a. 2, that is, the reading diaphragm is formed by three identical square slits, two of which are continuation of one another, and the third is shifted relative to the first by a distance equal to half the sampling resolution of one of the two coarse reference tracks. Sources of information taken into account in the examination 1. Gauf M. Electronic theodolites and tacheometers. M., Nedra, 1978, with. 83-95. 2. USSR author's certificate number 475502, cl. G 01 S 1/04, 1967 .. 2. USSR author's certificate No. 501273, cl. G 01 S 1/04, 1967. 4. USSR author's certificate No. 387209, cl. G 01 C 1/06, 1970. a . five S I I lit 53