RU2560011C1 - Laser range finder - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: laser range finder comprises a laser transmitter, a receiver of radiation reflected by an object, serially connected a multichannel storage connected to a clock pulse oscillator, and a distance meter. At the same time a switchboard is introduced at the output of the receiver. The first output of the switchboard is connected to the input of the multichannel storage, and at the second output of the switchboard there is a serially connected unit of time fixation and a unit of interpolation connected to the clock pulse oscillator. A unit of mode switching is introduced between the output of the range finder and the control input of the switchboard.

EFFECT: provision of altitude measurements from an aircraft board, as well as measurements of vertical component of speed both in stationary flight and during take-off and landing in a wide range of altitudes and modes of climb and descent.

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Description

The invention relates to measuring technique and can be used in any field where it is necessary to determine the speed of a moving object and the distance to it, in particular for monitoring the relief of the underlying surface and controlling the landing mode of the aircraft (LA).

A known laser range finder containing a laser transmitter, a receiver reflected by the object of radiation and a range meter based on the meter of the time interval between the probe and the reflected target pulses [1].

The disadvantage of this rangefinder is the insufficient range when using a semiconductor laser as a transmitter.

The closest in technical essence to the proposed device is a laser range finder with incoherent accumulation of the reflected signal [2], containing a laser transmitter, a receiver reflected by the radiation object, a multi-channel drive connected in series with a clock generator, and a range meter.

This device allows measurements of significant heights [4], but does not have the ability to measure the vertical component of the speed of the aircraft in the modes of its take-off and landing.

The objective of the invention is the provision of measurements from the aircraft of its height and vertical component of speed both in stationary flight and during take-off and landing in a wide range of heights and modes of rise and fall.

This problem is solved due to the fact that in the known laser range finder containing a laser transmitter, a receiver reflected by the radiation object, a multichannel drive connected to a clock generator, a range meter, a switch is introduced at the receiver output, the first output of which is connected to the input of a multichannel drive , and at the second output of the switch, a temporarily fixed block and an interpolation block connected to a clock generator, and between the control input A mode switching block is introduced by the switch and the outputs of the range meter and the interpolation block.

In FIG. 1 presents a diagram of a range finder-speed meter that implements the proposed method.

The device comprises a transmitter 1 and a receiver 2 connected to a switch 3 with two outputs. At one of the outputs of the switch, a multi-channel drive 4 is connected, connected with a range meter 5. Between the output of the range meter and the control input of the switch, a mode switching unit 6 is connected, which is also connected to the control unit 7. At the second output of the switch 3, a temporary fixation unit 8 is connected, connected with the interpolation unit 9. The interpolation unit and the range meter are synchronized by a timing oscillator 10.

At the beginning of the process of measuring the altitude and range of the aircraft, on a command from the control unit 7, the switch 3 switches the output of the receiver 2 to the input of the temporary fixation unit 8, and the interpolation unit calculates the vertical speed and altitude of the aircraft. At times T _i , a series of range measurements is performed in a single-pulse mode. The number m of soundings is determined by a given period of updating information and accuracy requirements. Estimates of the distance to the object R ₀ at the initial moment of measurement and the speed of the object V are formed in the interpolation block 9 according to the formulas

Where

R ₀ - assessment of the distance to the object at time T ₁ ;

V is an estimate of the speed of the object;

R _i = с · t _i / 2 - the result of measuring the distance to the object in the i-th sounding;

T _i - time points at which measurements of the range R _i ;

c is the speed of light;

m is the number of range measurements in the series;

t _i is the delay between the moments of radiation of the laser pulse and the reception of the radiation reflected by the object in the i-th sounding.

The distance to the object R and its relative speed V are determined in the interpolation unit 9 by linear interpolation of the measurement results in the form R (t) = Vt + R ₀ , where R (t) is the current distance to the object; t is the current time counted from the beginning of a series of soundings; V is the speed estimate; R ₀ is an estimate of the distance to the object at t = 0. The range estimate can be determined for any moment in time t, including for the end of a series of soundings t = T _m . This estimate is fed to the input of the mode switching unit 6.

, где j - порядковый номер ячейки дальности; Р_max - максимальное число ячеек дальности, соответствующее диапазону измерения дальности; {S_0j} - массив выборочных значений зондирующего импульса; {S_j} - массив накопленных значений принятых реализаций; р - текущее количество шагов при пошаговом сдвиге {S_j}. Затем измеритель дальности 5 определяет дальность R по формуле R=сРΔt/2, где с - скорость света; Р - номер ячейки дальности, соответствующий положению накопленного массива; Δt - длительность тактового интервала. Вертикальная составляющая скорости V в этом случае может быть определена как относительное приращение высоты R за период Т между j-м и (j-1)-м измерениями V=(R_j-R_j-1)/T.If at some moment the measured value of R begins to exceed the preset value of R _max , then the mode switching unit 6 switches the output of the switch 3 to the input of the multi-channel drive 4, synchronized by the clock generator 10, and a series of target sounding is performed by the method of incoherent accumulation [2]. At the end of the accumulation process, that is, when the accumulated sum reaches the required level in at least one range cell, the range meter analyzes the accumulated data array, determining the position of the accumulated array relative to the time scale according to the established criterion [2], for example, according to the maximum correlation function $$W\left(p\right)={\displaystyle \sum _{j=\mathrm{one}}^{P_{\max }}{S}_{0j}}\cdot S_{j+p}$$

where j is the ordinal number of the range cell; P _max - the maximum number of range cells corresponding to the range of range measurement; {S _0j } - an array of sample values of the probe pulse; {S _j } - an array of accumulated values of the adopted implementations; p is the current number of steps in a stepwise shift {S _j }. Then the range meter 5 determines the range R according to the formula R = cPΔt / 2, where c is the speed of light; P is the number of the range cell corresponding to the position of the accumulated array; Δt is the duration of the clock interval. The vertical component of the velocity V in this case can be defined as the relative increment of the height R for the period T between the jth and (j-1) -th measurements V = (R _j -R _j-1 ) / T.

If the measured range R is greater than the preset value R _max determined by the flight task of the aircraft, then the measurements continue in the described mode. When the aircraft lands, that is, when R <R ₀ , the mode switching unit switches the switch to the output associated with the temporary fixation unit, and measurements are performed in the single-pulse mode described above.

This invention allows:

- increase the measured height of the aircraft to 1000-2000 m;

- reduce the minimum measured height to 2 m;

- provide a minimum information update period of the order of 1 s at high altitudes and up to 0.1 s at low altitudes;

- to provide a minimum velocity measurement error of 0.01-0.1 m / s depending on the duration of the series of soundings and the number of measurements in the series;

- interpolate the results at any point in the measurement period or extrapolate them for a specified time in advance.

These conclusions are confirmed by testing prototype altimeter-speed meter [4, 5]. This confirms the solution of the problem - providing measurements from the aircraft of its height and vertical velocity component both in a stationary flight, and during take-off and landing in a wide range of heights and modes of rise and fall.

Information sources

1. V.A. Smirnov. Introduction to optical electronics. M .: Soviet Radio, 1973, p. 189.

2. V.G. Vilner et al. Evaluation of the capabilities of a radar range meter with accumulation // Photonika, 2007, No. 6, p. 22-26 is a prototype.

3. A method for determining the range and / or speed of a remote object. RF patent No. 2378705.

4. Small-sized laser altimeter DL-5M // Photonics, No. 3, 2013, p. 55.

5. V.G. Vilner et al. Ways to achieve extreme accuracy of a laser speedmeter // Mir izmereniya, No. 7, 2010, p. 17-21.

Claims (1)

A laser rangefinder comprising a laser transmitter, a receiver reflected by the radiation object, a multichannel drive connected in series with a clock generator, and a range meter, characterized in that a switch is introduced at the output of the receiver, the first output of which is connected to the input of the multichannel drive, and at the second output of the switch sequentially connected block of temporary fixation and an interpolation block connected with a clock generator are introduced, and between the control input of the switch and the outputs measure a range switch and an interpolation block; a mode switching block is introduced.