DE1959828B2 - DEVICE FOR STAR PATTERN RECOGNITION USING OPTICAL FILTERING - Google Patents

Description

3 4

thus become opaque, d. H. also impenetrable in the image plane of the receiving optics, i.e. on the photographic

liissig for the coherent (monochromatic layer) reflected in, against the optical axis in its

chromatic) light. translational orientation is shifted, so

The incoherent constellation musier, which does not indicate any disadvantage, since it was caught behind the plane of the satellite optics, an image lens is then arranged as a coherent light pattern over a lens in such a way that its front focal plane becomes the HoIo hologram of a given constellation pattern is gram level. If that's thrown from the satellite. The holograms of the given constellation optics captured constellation patterns - on the photo pattern are made of constellation patterns - chrome layer z. B. Below the optical axis, photographs that were taken on reversal film (stars white, to is imaged (i.e. shifted downwards is dark in the background) or normal film (dark stars, its translational orientation), so the background is intact). Which constellation pattern correspondence of the bright light type of film is used depends on the photochromic layer seen through the image lens in its rear image plane. The one shown shifted upwards. This storage is reflected laser light comes either from an i ₅ measurable and can be used together for position determination continuous wave laser or from a pulse laser. of the satellite. The offset is measured. With continuous wave lasers, the intensity has to be set either with the help of photodetector matrices or a value such that the optical fibers, on each of which a small photochromic layer detects the laser light, are still attached.

absorbed. As a result, the photochromic layer is a principle example of the practical pre-load. When operating with the pulse laser guide a device according to the invention is in however, you can set it up so that the photo of the drawing is shown schematically and is in the chrome layer at the points of the star images described below.

is already transparent through the starlight before the number 1 is the optical axis of the

Light pulse of the pulse laser on the layer on- as rätes called. With a spin stabilized satellite

falls. Uten forms the satellite optics 2 by the half

The photochromic layer is in the front transparent mirror 6 a constellation pattern on the Focal point of an objective lens. This removes photochromic layer 7 (for example at point 1.6). from that shining coherently on the photochromic layer in the case of a three-axis stabilized satellite Constellation patterns in the rear focal point are necessary because of the rotational plane of orientation the Fourier transform is generated. In the tion in front of the satellite optics 2 an Amici reversing rear The focal plane of this objective lens will set prism 3 (with cover 3 α). The Amiciaber Fourier holograms given star prism 3 rotates around a virtual axis that sample passed. The laser beam with which the optical axis 1 is equal. An angle of rotation the given constellation transmitter 4 continuously measures the angle of rotation of the holograms Patterns can be reproduced is through the Amici prism 3. With some photochromic captured constellation patterns modified. In a HoIo layer it is favorable that they keep coming back gram of a given constellation pattern is made dark or can be kept dark in this way illuminated with the Fourier transform. These photochromic layers are only on this modification, the coherently luminous 40 those places bright and transparent, i.e. from constellation patterns, which is bleached on the photochromic, on which the (visible) star light is on the layer was imaged by the receiving optics. falls. Therefore, a lamp 19 can be attached who-votes now the captured with the given that, which radiates in a spectral range that of Constellation patterns match, then behind which the photochromic layer 7 is absorbed, this appears Image lens that becomes dark in its focal length distance behind 45. The lamp 19 operates continuously Hologram plane is arranged, a light borrowed or in pulse mode. When the laser 5 is on spot. Pulse laser is, the lamp 19 can, for. B. with

The holograms of given constellation patterns pulsate this alternately. In the case of photowerden on the outer circumference of a wheel arranged chromium layers passing through the constellation points net, which rotates around an axis that is parallel to 50 dark, i.e. impermeable, by the starlight is arranged to the optical axis of the device. A lamp 19 can be provided which Complex optical filtering is only applicable in a spectral range for which the bar, if the captured by the satellite optics, photochromic layer 7 bright, so bleached and the constellation imaged on the photochromic layer becomes permeable.

pattern and the given constellation pattern, which 55 The coherent, monochromatic light of a

ches is recorded holographically, exactly over-continuous wave or pulse laser 5 is over the

agree in their rotational orientation about mirror 6 thrown onto the photochromic layer 7.

the optical axis of the device. In the case of a twist on from optics 2 there (e.g. at point 16)

stabilized satellites, in which the device lights up the rigidly mapped constellation pattern thus cohesively

is built in so that its optical axis is rented in or 60. By means of a spherical lens 8 is in its

parallel to the spin axis, this problem is back focal plane (back focal length / ₍₎ ) of

easy to solve. In the case of a three-axis stabilized the (ζ. Β.; · Η of the point 16) coherently luminous

Satellites must have an Amici inverting prism in front of the constellation pattern, the Fourier transform is formed

be seen which z. B. in front of the satellite The layer 7 is in the front focal length of the

Receiving optics is arranged. see around a virtual 65 lens 8 (front focal length /, /; / ₍₎ '= / ₍₎ ). In the

Axis that will rotate equal to the optical axis of the rear focal plane of lens 8 will now be

Device is. Fourier holograms 9 of given constellation

If, on the other hand, the captured constellation pattern passes by. The Fourier holograms 9

I 959 828

are arranged on the circumference of a wheel 10 which rotates about an axis 11 which is parallel to the optical axis 1 of the device. A rotary encoder or counter 12 continuously indicates the numbers of the holograms 9. If the constellation pattern captured by the optics 1 and one of the constellation patterns specified in one of the holograms 9 match, a light spot appears behind the relevant Fourier hologram 9 or behind the lens 13.

The image lens 13 (front focal length f _s ', rear focal length / _ß ; / _ß ' = / _ß ) images the light spot on the image plane 14, e.g. B. to the point 17, if on the layer 7, the point 16 was permeable.

With the aid of detector matrices 15 or of optical fibers, on each of which small photodetectors hang, a shelf α can be determined. If a light spot is imaged on the image plane 14, the following is output via a calculation arrangement 18:

1. From the rotary encoder or counter 12 the number of the hologram 9, which is a predetermined one Constellation pattern is marked as recognized.

2. The shelves from the detector assembly 15.

3. In the case of a three-axis stabilized satellite from the Drehwinke'.geber 4 of the Drehwinkcl des Amici erecting prism 3. The spin angle of a spin-stabilized satellite.

With the data calculated under 2. one obtains the translational orientation, with 3. the rotary orientation of the constellation pattern captured in relation to

ao on the satellite.

The advantages achieved by the invention are that once the aforementioned object The solution is to create a simple device that uses spin and three-axis stabilized satellites is suitable, and that the two-dimensional image processing leading to quick and reliable recognition of constellation patterns. On the other hand, you have one relatively compact device which requires little space and weight. Furthermore, mar when recognizing a constellation pattern its rotatory and translational orientation in bezuj on the satellite. The device is equally suitable for ship and aviation navigation Purposes.

1 sheet of drawings

Claims (4)

the determination of the position of the satellite (NASA technical claims: Notes d 4740 and D 4742, T. M. Walsh et. al., 1968). Another method provides for a heavenly 1. to scan a device for recognizing constellation patterns with a television camera, by means of optical filtering, thereby 5 after you have marked their crosshairs on a »central, that the from the (satellite) star "has aligned. The measured radial optics Distances - and possibly - angular differences of the imaged on a photochromic layer incoherent constellation patterns made surrounding stars coherent (up to a certain by adding coherent, monochromatic size class) are then used with appropriate co-laser light io ordinates compared to the photochromic layer stored in the on-board computer is reflected and that the coherently luminous are (German Offenlegungsschrift 1 448 564). A Constellation pattern holograms given stem- further suggestion based on the use shine through image samples. is based on detector strips, the elements of which are 2. Device for recognizing constellation patterns is suitable for spin-stabilized satellites, by means of optical filtering according to claim 1, there being an optical system, the axis of which is parallel to the twist aclise characterized in that the laser is permanently eccentric to this, scans the streaked in connection with a pulsating sky due to the spin motion (NASA Contr. Lamp or that the laser as a pulse laser in Rep. CR-92671, P. M. Grant and J. M. Hanlet, Connection with an alternating pulsation to him 1966). Generating lamp, which is in a different spectral 20 in general, these methods are either only area radiates as the laser is operated. for three-axis stabilized or for spin stabilized 3. Device suitable for the recognition of constellation patterns, satellites. The image data processing means Optical filtering according to claims 1 takes place one-dimensionally sequentially instead of immediately and 2, characterized in that the HoIo- two-dimensional. The technical effort is programmed given constellation pattern on the 25 proportionally large. They are also significant Circumference of a wheel are arranged, which measures against the optical and electrical around an axis parallel to the optical axis noise is necessary. turns. The invention is based on the object 4. Device for recognizing constellation patterns to create a simple device, which equally by means of optical filtering according to the An 30 for three-axis and spin-stabilized satellites claims 1 to 3, characterized in that it is suitable, as far as possible, the image processing performs the rotational orientation of a recognized dimensionally , ar-constellation pattern developed relatively quickly with respect to the satellite and is not able to make yes or no decisions either through the measured momentary rotation. The object is achieved in that the angle of the Amici erecting prism or the instantaneous spin angle of the satellite coherently measured by the coherent light of a constellation pattern is made and the coherent constellation pattern light Uten and the translational orientation are passed through a complex optical filter.
Photo detector matrices or optical fibers can be determined with the device according to the invention for the detection of attached photo detectors. Constellations is characterized in that the 40 from (satellite) optics to photochromic The incoherent constellation pattern depicted in the layer can be made coherent by using coherent, mono- chromatic laser light on the photochromic Layer is reflected and that the coherent 45 luminous constellation pattern holograms are given Radiating constellation patterns. To do this, The invention relates to a device for recognizing a star pattern from the optics of the satellite, which of constellation patterns using optical filtering. is currently in the opening angle of the optics, The recognition of constellations has been mapped onto a special (photochromic) layer since ancient times, a requirement for navigation. To navigatori- 50 The light of every single star that hits the optics see purposes and also for orientation for the noticeable, as well as its illustration by that unmanned space travel, especially for satellite optics, is coherent. That which is striking on the optics Uten, are any devices or facilities needed to light a whole (at an angle of view from can recognize the constellations. Since the constellation pattern in the sky, e.g. + 5 °, is against it coordinates of the stars in the fixed star sky are known 55 not coherent. To that formed by optics provides the recognition or identification of constellation patterns now to make them coherent Constellations the basis for the further process dimensions of the optical arrangement required automatic navigation (position determination, borrowed, which is unrealistic in particular in satellites in connection with other sizes are also capable. Therefore, from the side it becomes a coherent one determination). 60 laser light reflected onto the layer. the To meet these requirements, different layers are fully illuminated by laser light, process became known. In Will, the light of the constellation was cincm through the optics The »scanner« project is mapped onto the layer using a pattern to the twist axis of a spin-stabilized satellite vertical optics translucent straight at the constellation points, the sky scanned. The evaluation, which 65 d. H. also permeable for the reflected co- (stronger light) Stars were caught in the process, hardened light followed. on the ground in Korrdntinn with data from the ground. Different photochromic layers have the Radar tracking. The main purpose of this is that it is dark at the constellation points,