Patent GB2145894A successfully refreshed from Google Patents.
GB2145894A
Expired / Lapsed
GB
⏱️ 0.0 years remaining
Optical transponder system
Assignee: Airbus Defence and Space GmbH
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Filing: 1984-07-31
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Granted: —
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Expires: 2004-07-31
Abstract
No abstract record available.
Inventors
- 👤 Dr Gunther Sepp
- 👤 Anton Harasim
Bibliographic Details
Application Number
—
Jurisdiction
GB
Data Source
google_patents
Last Synchronized
2026-10-23 11:40
CPC Classifications
G; G01; G01S; G01S17/00; G01S17/74
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
128 words
A long-range monitoring system for obtaining information from remote targets with simultaneous friend/foe identification (IFF), said system comprising a controlled laser transmission device incouding a wave lengthstabilised semiconductor laser controlled by an IFF-code generator and an associated retroreflector device which is activated only by a laser transmission beam having the predeter- mined IFF-code of the IFF-code generator of the laser transmission device, the radiation of the laser being directed onto the retroreflector device, in which respect the signal picked up by the retroreflector device is fed to a retro- modulator having an interference fitter and the reception beam reflected back from the retro reflector device is detected in a laser reception device, is filtered and is fed to control appara tus and a demodulator with a first converter.
Claim 2
Dependent Claim
128 words
A long-range monitoring system for obtaining information from remote targets with simultaneous friend/foe identification (IFF), said system comprising a controlled laser transmission device incouding a wave lengthstabilised semiconductor laser controlled by an IFF-code generator and an associated retroreflector device which is activated only by a laser transmission beam having the predeter- mined IFF-code of the IFF-code generator of the laser transmission device, the radiation of the laser being directed onto the retroreflector device, in which respect the signal picked up by the retroreflector device is fed to a retro- modulator having an interference fitter and the reception beam reflected back from the retro reflector device is detected in a laser reception device, is filtered and is fed to control appara tus and a demodulator with a first converter.
Claim 3
Dependent Claim
67 words
A system as claimed in claim 1 wherein the retromodulator includes a liquid crystal modulator formed from two or more glass plates which are arranged one behind the other and which are separated fron one another by distance pieces, a-liquid crystal mixture consisting of a nematic liquid crystal mixture with high optical anisotrophy and a cholestrinic liquid of the concentration c=const.n/X being introduced into the resulting interstices.
Claim 4
Dependent Claim
63 words
A system as claimed in claim 1 wherein the retromodulator includes a liquid crystal modulator formed from two or more glass plates which are arranged one behind the other and which are separated from one another by distance pieces, a ferro-electrical liquid crystal mixture being introduced into the resulting interstices and a polariser being arranged in front or after the liquid crystal cell.
Claim 5
Dependent Claim
68 words
A system as claimed in claim 2 or 3 wherein the reflector device included an IFFguard circuit, a converter, and the interference filter disposed in front of a retroreflector, and wherein the laser reception device includes a laser receiver with an interference filter, a reception optical system, a photodetector, an amplifier, and an IFF-code filter as well as the control apparatus and the demodulator with the first converter,
Claim 6
Dependent Claim
63 words
A system as claimed in claim 4, characterised in that during a target acquisition phase the control apparatus, by means of a zoom transmission optical system of a target acquisition and tracking device, causes a large divergence of the leaser transmission beam and sets a beam control to a search mode in which the laser transmission beam scans a predetermined solid angle region.
Claim 7
Dependent Claim
59 words
A system as claimed in claim 5, characterised in that, after initial detection of the laser reception beam, the control apparatus initiates a target tracking phase by setting the zoom transmission optical system to the least- possible divergence of the laser transmission beam and adjusting the beam control so that the intensity of the laser reception beam is maximised.
Claim 8
Dependent Claim
90 words
A system as claimed in claim 4, 5 or 6 wherein the IFF-guard circuit includes a laser receiver with a narrow- band interference filter corresponding to the wave length of the semiconductor laser, a reception optical system, a photodetector and an amplifier as well as an IFF-code filter, the output of which is monitored by a control apparatus which, in the event of the existence of a reception signal, activates the retromodulator which includes athe second converter, and an amplifier as well as the liquid crystal modulator. 6 GB2145894A 6
Claim 9
Dependent Claim
75 words
A system as claimed in claim 7 wherein the IFF-guard circuit includes an additional laser receiver with a wideband interference filter which is however not transmissive for the wave length of the semiconductor laser, a 70 reception optical system and an amplifier, the output of which is monitored by the control apparatus which, in the event of the existence of a reception signal, deactivates the liquid crystal modulator and the converter for a specific time.
Claim 10
Dependent Claim
57 words
A system as claimed in claim 8, charac terised in that during the target tracking phase, in the event of loss of the laser recep tion beam for a specific time, the control apparatus interrupts the emission of the laser transmission beam for a specific time corre sponding to the deactivation time of the liquid crystal modulator.
Claim 11
Independent Claim
26 words
A system as claimed in any of claims 2 to 9 characterised in that the liquid crystal modulator in the deactivated or---off--state has only minimum transmission.
Claim 12
Independent Claim
57 words
A system as claimed in any of claims 2 to 10 characterised in that the 1 FF-code generator generates a periodically modulated IFF-code signal the limiting freqency of which is selected to be large compared to its fundamental frequency and the fundamental fre- quency of which is equal to the limiting frequency of the liquid crystal modulator.
Claim 13
Independent Claim
53 words
A system as claimed in any of claims 4 to 11, characterised in that the IFF-guard circuit recognises the IFF-code signal, within one or less periods of the fundamental fre- quency thereof, carries out this check con stantly and, in accordance with the test result, activates or deactivates the liquid crystal mo dulator.
Claim 14
Independent Claim
70 words
A system as claimed in any of claims 105 4 to 12, characterised in that connected sub sequent to the second converter is a fre quency shifter which shifts the frequency band that is to be transmitted by about 1 kHz to higher frequencies, and in that connected prior to the first converter is a corresponding freqeuncy shifter which shifts the transmitted frequency band back again by the same amount.
Claim 15
Independent Claim
42 words
A system as claimed in one or more of claims 4 to 13, characterised in that the IFF-code generator is a quartz-stabilised oscil lator and the. 1 FF-code filter is a band filter corresponding to the frequency of the oscilla- tor. -
Claim 16
Independent Claim
28 words
A system as claimed in any of claims 4 to 14, characterised in that the second converter is a microphone and the first con verter is a loudspeaker.
Claim 17
Independent Claim
31 words
A system as claimed in one or more of claims 4 to 14, characterised in that the second converter is a television camera and the first converter is a television screen.
Claim 18
Dependent Claim
23 words
A system as claimed in any of claim 5 to 16, characterised in that the beam control comprises two motor-driven rotating wedge compensators.
Claim 19
Independent Claim
18 words
A system as claimed in any of claims 4 to 17 wherein the retroreflector is a retroreflector foil.
Claim 20
Independent Claim
27 words
A system as claimed in any preceding claim wherein the effective aperture of the retromodulator is arranged in the centre of the retroreflector device, which is disc-shaped.
Claim 21
Dependent Claim
42 words
A system as claimed in claim 7 and 8, characterised in that the laser receivers have a common reception optical system and a narrow-band interference filter which is arranged as beam divider and corresponds to the wave length of the semiconductor laser.
Claim 22
Independent Claim
37 words
A system as claimed in any of claims 2 to 20, characterised in that, upon use of liquid crystal mixtures which display a twofrequency behaviour, the control voltage can be modulated both in amplitude and in frequency.
Claim 23
Dependent Claim
44 words
A system as claimed in claim 2 or any of claims 4 to 2 1, characterised in that the liquid crystal mixture consists of a nematic liquid crystal, a cholestrinic doping substance and a dichroic dyestuff, which work in accordance with the guest/host effect.
Claim 24
Independent Claim
44 words
A system as claimed in any of claims 2 to 22, characterised in that the front glass side of the liquid crystal modulator is provided with a transparent conductive electrode which is in conducting contact with a metallic shield or with a metal housing.
Claim 25
Independent Claim
72 words
A system as claimed in any of claims 4 to 23, characterised in that two logarithmically sensitive photodetectors are arranged on that side of the liquid crystal modulator which face the retroreflector in such a way that the one is inside and the other is outside a region filled with liquid crystal, and in that the output signal of the photodetectors connected in opposition is fed to a difference amplifier with regulator.
Claim 26
Dependent Claim
59 words
A long-range monitoring system for obtaining information from remote targets with simultaneous friend/foe identification (IFF) substantially as hereinbefore described with reference to and illustrated in the accompanying drawings. Printed in the United Kingdom for Her Majesty's Stationery Office, Dd 8818935, 1985. 4235. Published at The Patent Office, 25 Southampton Buildings. London, WC2A lAY, from which copies may be obtained.
Claim 27
Dependent Claim
59 words
A long-range monitoring system for obtaining information from remote targets with simultaneous friend/foe identification (IFF) substantially as hereinbefore described with reference to and illustrated in the accompanying drawings. Printed in the United Kingdom for Her Majesty's Stationery Office, Dd 8818935, 1985. 4235. Published at The Patent Office, 25 Southampton Buildings. London, WC2A lAY, from which copies may be obtained.
References Cited (Backward Citations)
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