JPS63145910A - Device for determining distance between two body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The invention relates to a device for determining the distance between two objects according to the preamble of claim 1.

PRIOR ART The device according to claim 1 is characterized in that by interpolation of the light spots occurring on the detector array, the center of gravity is smaller than the diameter of the sensor element, insofar as the diameter of the light image is larger than the diameter of the sensor element. It is based on the recognition that it can be determined with precision. Typically, the center of gravity is 10 times the diameter of the sensor element.
Determined with ~2% resolution. The covering (filling) of a light spot by multiple sensor elements can be achieved, for example, by corresponding imaging,
This is caused by the effects of defocusing (defocusing) and/or aberrations.

When determining the center of gravity of a number of light spots, it is of course necessary that the individual light spots do not overlap. In the case of superposition of a number of light spots, the individual centroids of the light spots are not determined, but rather the common centroid of the superposed centroids.

In the device for distance determination according to the preamble of claim 1, the condition that the individual images of the retroreflectors are not superimposed is determined by the given field of view of the detection array and the given field of view of the individual retroreflectors. Distance limits the maximum distance to be determined. For example, 385 x 288 sensor elements with dimensions of 22 μm x 22 μm each, each having dimensions of 0.67 degrees x 0.
With a detector array with a field of view of 5 degrees, object distances up to 4400 m can be determined for a retroreflector distance of 0.8 m.

Large distances are no longer resolved, since the retroreflector images do not overlap.

(Problem of the invention) The present invention provides a device for the determination of the distance between two objects, which makes it possible to determine a distance greater than in the case of the device assumed in the generic concept of claim 1. The challenge is to provide.

(Means for Solving the Problem) According to the present invention, this problem is solved by the configuration described in the claims.

Effects of the Invention The invention is based on the basic idea that images of retroreflectors that can no longer be resolved angularly with a given detector array can be resolved by means of an optical counder.

In the device according to the generic concept of claim 1, the illumination device sequentially illuminates the retroreflector units with light of different wavelengths, and each of the retroreflectors has only one
This is done by reflecting two wavelengths of light. Images of the individual retroreflectors are thus produced sequentially on the detector array. Since the images cannot be superimposed, the centroid of each image can be determined with the maximum possible resolution even in the case of large object distances. The maximum measurable distance is limited only by the resolution of the detector array for the centroid of the light spot or, in other words, differences in the positions of the images of the individual retroreflectors can be resolved. .

For example, with similar field of view and retroreflector spacing data with the detector array and the device according to the invention described by way of example at the beginning, a limit distance of 132 km is obtained. The maximum distance that can be determined is 30 times greater than in the device as envisaged in the preamble of claim 1.

Other configurations of the invention are described in the embodiment section.

For example, according to claim 2, by using at least three clearly distinguishable retroreflectors, it is possible to determine not only the distance between the two objects, but also their relative positions. Become. The identification of the retroreflectors here is made, for example, by the fact that the retroreflectors have different spacings and/or reflectances for the light that reaches them.

The optical counder used according to the invention can not only be used to distinguish between individual reflectors of a retroreflector unit, but also to distinguish between different objects. A possibility for this is specified in claim 3.

Of course, other possibilities for identification can also be used on the basis of the basic idea according to the invention, which allows a highly accurate determination of the center of gravity of the images of individual retroreflectors. For example, the specific shape of the retroreflector can be used for identification.

Claim 4 indicates a particularly advantageous construction which makes possible an optical counder in a simple manner.

The basic idea of the optical counder according to the invention can be constructed in an advantageous manner by the use of optical systems with variable focal length, for example vario or switching optical systems. With such an optical system, the field of view of the sensor can be adapted to the distance to be measured, so that within a certain distance range measurements can be made with particularly high resolution.

A particularly advantageous use of the device according to the invention is specified in claim 6. The device according to the invention allows not only the determination of the distance between two satellites, but also the detection of the relative position and differentiation of many different objects.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a cross-sectional view of an illumination device for a retroreflector, not shown in FIG. 1, and a sensor for light reflected by the retroreflector, formed according to the invention. .

The illumination device has four photovoltaic cells 11, 12, 13 and 14, the light of which is introduced into a common optical path 4 via a prism device 2 and a projection lens 3. The optical path 4 is directed onto a retroreflector unit mounted on another object. The light 5 reflected from the retroreflector unit is imaged onto a detector array 7 via an objective lens 6, which is shown only diagrammatically in FIG.

The detector array 7 and the different photocells 11-14 are connected to the conductor 8
1.82.83.84 and 85 to a control unit (not shown).

FIG. 2a shows an arrangement of three retroreflectors 91, 92, and 93. The retroreflectors are arranged at different distances X1 or x2 at the corners of a right triangle. At a distance from the retroreflector, the reflection characteristics τi(λ) described in FIG. 2c
There is a filter, not shown in detail, which has a transmittance characteristic that imparts to each retroreflector/filter unit.

The method of operation of the device shown in FIGS. 1 and 2 will be described on the basis of FIG.

A control unit (not shown) controls the photovoltaic cells 11 to 14 via conductive wires 81 to 84 so that the photovoltaic cells sequentially detect light in time. As shown in FIG. 2b, the light fluxes I of the individual light sources have different wavelengths, so that the light from the light source 11 is transmitted only by the retroreflector 91, and the light from the light source 12 is transmitted only by the retroreflector 91.
and the light of the light source 13 is reflected only by the retroreflector 93. The light from light source 14 is not reflected.

According to the spacing of the illuminator/sensor unit shown in FIG. 1 from the retroreflector unit shown in FIG. 2a, the retroreflector image shown in FIG. 3a or 3b is thereby placed on the detector array 7. arise. At that time, retroreflector 91.92
．． Nine tin images 91', 92', and 93' are generated sequentially in time in accordance with the brightness of the light sources 11-13.

Thus, even at large distances at which the individual images are superimposed, as shown in FIG. 3b, the individual images are separated (FIG. 3a), and not only at small distances, but also at The center of gravity of the points can be detected by a control unit, not shown.

The detection of the centroid of the individual light spots is carried out by means of known interpolation forces, the method being similar to the formula used in the mechanism for centroid detection, so that no further explanation is necessary here.

The detected centroid of the retroreflector image is detected by a control unit, for example a microcomputer or a hard-wired calculation circuit, which, for a given retroreflector spacing and focal length of the imaging lens, coordinates the sensor and the retroreflector according to the theorems of geometry. Calculate the distance between the reflector unit. For example, 2 each
Sensor element 385X2 with dimensions 2μta x 22μm
A detector array with 8B detectors and a field of view of 0.67 degrees by 0.5 degrees makes it possible to determine object distances up to 132 km with a retroreflector spacing of 0.8 m.

Furthermore, the selection of the geometry of the array of retroreflectors when using more than one reflector and/or reflective properties makes it possible to identify the object whose distance is to be measured.

The individual retroreflectors 91-93 are completely identified on the basis of the optical Coanda, in other words by the time of the response of the incident light.

Identify four different objects, e.g. a docking partner for a satellite, if you already use four light sources of different wavelengths and three retroreflectors for each object whose distance is to be measured. It is possible to do so.

Many objects can be identified by additional selection of reflectance and/or geometry.

FIG. 2c diagrammatically shows the different reflectivities of individual retroreflectors.

Although the invention is shown by way of example in the embodiments, it is of course possible to make various modifications in actual implementation.

For example, the objective lens 6 has a variable focal length, for example, a vario lens, in order to obtain high resolution within a specific distance measurement range.
Alternatively, it may be an objective lens with an insertable lens member.

Various objects can be used as light sources, for example lasers. Furthermore, it is possible to use light sources which are preceded by different filters.

The number of light sources and the number of retroreflectors are also not limited to the examples.

For example, different semiconductor elements can be used as the detector array.

[Brief explanation of the drawing]

FIG. 1 shows a cross-sectional view of the illuminator and sensor, and FIG. 2a shows different images of the retroreflector on the imager array. Reference numeral 6 in the figure: Objective lens 11.12.13.14.2.3... Illumination device 7
...detector array

Claims (6)

[Claims] (1) A device for determining the distance between two objects, one comprising a retroreflector unit comprising at least two mutually spaced reflectors (91, 92, 93);
The other is a lighting device (11, 1) for the retroreflector unit.
2, 13, 14, 2, 3), each reflector of the retroreflector unit is imaged by an objective lens (6) with a detector array ( 7) and a control unit, wherein the control unit detects the center of gravity of the image of the reflector and determines the distance from the spacing of the center of gravity of the image, wherein each retroreflector (91, 92, 93) The lighting device reflects light of different wavelengths, and the lighting device sends out the light of different wavelengths to be reflected by the retroreflectors in temporal succession, and the control unit generates the retroreflectors separately in time. The device characterized in that it determines a distance from an image of. (2) In order to additionally determine the relative position of the objects, one object has at least three mutually spaced retroreflectors (91, 92, 93), the spacing and/or reflectivity of which is A device according to claim 1, which is different. (3) A device according to claim 1 or 2, wherein each object has fewer retroreflectors than the illumination device detecting light of different wavelengths for identification of each different object. (4) A filter is arranged in front of each retroreflector, the spectral transparency of which allows reflection of only light in a specified wavelength range. Apparatus according to any one of the above. 5. Device according to claim 1, characterized in that the focal length of the lens system is variable in order to adapt the sensor field of view to the distance to be measured. (6) A device for determining the distance between two objects, one comprising a retroreflector unit comprising at least two mutually spaced reflectors (91, 92, 93);
The other is a lighting device (11, 1) for the retroreflector unit.
2, 13, 14, 2, 3), each reflector of the retroreflector unit is imaged by an objective lens (6) with a detector array ( 7) and a control unit, the control unit being the device for detecting the center of gravity of the image of the reflector and determining the distance from the spacing of the center of gravity of the image,
92, 93) reflect light of different wavelengths, the illumination device sends out light of different wavelengths successively in time, each reflected by a retroreflector, and the control unit is separated in time. A method of using said apparatus for determining distances from images of retroreflectors generated by objects in space for determining the spacing and relative positions of objects in space.