WO2004021072A2

WO2004021072A2 - Electro-optic platform

Info

Publication number: WO2004021072A2
Application number: PCT/IL2003/000591
Authority: WO
Inventors: Vladimir Sherman
Original assignee: Vladimir Sherman
Priority date: 2002-07-18
Filing date: 2003-07-20
Publication date: 2004-03-11
Also published as: AU2003242979A1; WO2004021072A3

Abstract

As part of the present invention, there is provided an electro-optic platform having a modulated light source, a scanning optics block adapted to receive light from the light source, and a beam targeting system adapted to determine the relative direction of an object to be illuminated. The beam targeting system is also being adapted to produce a control signal intended to cause the scanning optics to direct light from the light source to the object.

Description

ELECTRO-OPTIC PLATFORM

FIELD OF THE INVENTION

The present invention relates generally to the field of electro-optics. More particularly, the present invention relates to an electro-optic platform which may be fixed or attached to a vehicle moving on land, water or air, and which platform may perform functions such as obstacle detection, communication, and target localization.

BACKGROUND OF THE INVENTION

The fields of photonics and electro-optics have seen tremendous development and growth over the past twenty years. Every time someone picks up a phone or uses their computer to access a website, they are most likely receiving or transmitting data over a fiber-optic network, which network was made possible by technologies developed in the fields of photonics and electro-optics. Similarly, many security related systems for the detection and ranging of objects are also based on technologies developed in the fields of electro-optics and photonics.

Although photonic and electro-optic technologies have to a certain extent enabled the above mentioned applications, implementation of the above mentioned applications are still, for the most part, quite complicated and require considerable human participation. For example, establishing an optical communication network (e.g. fiber-optic network) requires manual alignment of an optical transmitter and receiver, either by using connecting optical fibers or by focusing the photonic output of the optical transmitter onto the active area of the optical receiver, which receiver must be in line-of-site of the transmitter. Similar to the drawbacks of the present day optical communication systems, electro-optic based systems for obstacle detection and object localization (e.g. target acquisition) are still quite crude and may benefit from being integrated with automated control and/or targeting systems.

SUMMARY OF THE INVENTION

The present invention is an electro-optic platform, which platform may include a light source such as a laser or laser diode, light beam targeting or scanning optics, and a controller providing targeting or scanning signals to the targeting or scanning optics. According to some embodiments of the present invention, the output of the light source may be modulated with a data signal or a ranging pulse. According to further embodiments of the present invention, the controller may be part of a beam-targeting/object-tracking system which may be configured to track a specific target to be illuminated by the light source, and which may provide signals to the scanning optics intended to cause the scanning optics to direct the output of the light source onto the object/target being tracked. According to some embodiments of the present invention, the target being tracked may be an optical receiver or may be another object whose coordinates maybe of interest.

According to some embodiments of the present invention, there may be provided a system and method of maintaining an optical communication link between two or more vehicles, aircraft or other non-fixed devices between which maintenance of communications would be desirable. An optical communication link according to the present invention may be established using a modulated light source (e.g. laser source), where the laser is modulated with a data signal. An optical receiver may receive the modulated light from the light source and may extract from the light the original data signal. A beam targeting system may be used to direct a light beam from the light source towards the receiver. The targeting system may include a target acquisition and tracking system, which may be adapted to lock in on some feature of the receiver, for example, in case the position of the receiver relative to the modulated light source is not constant. Beam targeting optics may direct the light beam to the tracked object/target, which may be the receiver.

According to some embodiments of the present invention, the beam targeting system may include a CCD or CMOS image acquisition device adapted to acquire images. Based on an analysis of the acquired video images, an object's/target's direction relative to the system (e.g. relative angles in the x and y planes) may be determined and the targeting system may issue a command or signal intended to direct the beam targeting optics to direct light from the light source in the direction of the target. According to some embodiments of the present invention, a light pulse of a fixed duration (e.g. 150 nanoseconds) may be used to determine the distance of the targeted object from the system. An optical receiver, which may either be part of the targeting system or which may be part of a common optical arrangement with the light source and scanning optics, may be used to receive reflections of the light pulse from the targeted object. By timing the period between the pulse's start and the optical receiver first registering or receiving the reflection, the distance or range of the object from the system may be calculated.

According to some embodiments of the present invention, the targeted object's position relative to the system (e.g. the object being at x, y, z coordinates, while the system may be defined as either the center or some other point in the coordinate space) may be determined using the relative direction and distance/ranging data acquired as described above. The targeted object's absolute position (e.g. longitude, latitude and altitude) may be determined by offsetting the system's own absolute position (e.g. longitude, latitude and altitude as determined with the aid of a GPS system) by the targeted object's position relative to the system.

BRIEF DESCRIPTION OF THE FIGURES

The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with containers, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings in which: Fig. 1 is a diagram depicting several aircraft flying in formation and communicating with one another using directed optical communication links according some embodiments of the present invention; Fig. 2 is a diagram showing a directed optical transmitter according to some embodiments of the present invention;

Fig. 3 is a diagram showing an optical receiver assembly, with a beacon, according to some embodiments of the present invention; Fig. 4 is a diagram showing the transmitter of Fig. 2 sending a targeted optical data stream to the receiver assembly of Fig. 3, according to some embodiments of the present invention; and

Fig. 5 is a diagram showing a directed optical transmitter according to some embodiments of the present invention used to localized or determine the position of a targeted object. It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to obscure the present invention.

Unless specifically stated otherwise, as apparent from the following discussions, it is appreciated that throughout the specification discussions utilizing terms such as "processing", "computing", "calculating", "determining", or the like, refer to the action and/or processes of a computer or computing system, or similar electronic computing device, that manipulate and or transform data represented as physical, such as electronic, quantities within the computing system's registers and or memories into other data similarly represented as physical quantities within the computing system's memories, registers or other such information storage, transmission or display devices.

Embodiments of the present invention may include apparatuses for performing the operations herein. This apparatus may be specially constructed for the desired purposes, or it may comprise a general purpose computer selectively activated or reconfigured by a computer program stored in the computer. Such a computer program may be stored in a computer readable storage medium, such as, but is not limited to, any type of disk including floppy disks, optical disks, CD-ROMs, magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), electrically programmable read-only memories (EPROMs), electrically erasable and programmable read only memories (EEPROMs), magnetic or optical cards, or any otlier type of media suitable for storing electronic instructions, and capable of being coupled to a computer system bus.

The processes and displays presented herein are not inherently related to any particular computer or other apparatus. Various general purpose systems may be used with programs in accordance with the teachings herein, or it may prove convenient to construct a more specialized apparatus to perform the desired method. The desired structure for a variety of these systems will appear from the description below. In addition, embodiments of the present invention are not described with reference to any particular programming language. It will be appreciated that a variety of programming languages may be used to implement the teachings of the inventions as described herein.

The present invention is an electro-optic platform, which platform may include a light source such as a laser or laser diode, light beam targeting or scanning optics, and a controller providing targeting or scanning signals to the targeting/scanning optics.

According to some embodiments of the present invention, the output of the light source may be modulated with a data signal. According to further embodiments of the present invention, the controller may be part of a targeting or tracking system which may be configured to track a specific target and which may provide signals to the scanning optics, directing the scanning optics to direct the output of the light source onto the target being tracked, thereby illuminating the target with light from the light source. According to some embodiments of the present invention, the target being tracked may be an optical receiver or may be another object whose coordinates may be of interest.

According to some embodiments of the present invention, there may be provided a system and method of maintaining an optical communication link between two or more vehicles, aircraft or other non-fixed devices between which maintenance of communications would be desirable. Optical communication links according to the present invention may be established using a modulated light source (e.g. laser source), where the light source may be modulated with a data signal. An optical receiver may receive the modulated light from the light source and may extract from the light source the original data signal. A targeting system may be used to direct the modulated light source's light beam towards the receiver and to illuminate the receiver. The beam targeting system may include an object/target acquisition and tracking system, for example, in case the position of the receiver or the object relative to the modulated light source is not constant. The object/target acquisition and tracking system may be adapted to lock in on some feature of the target (e.g. receiver) and may also include beam targeting optics which may direct the light beam to the target.

According to some embodiments of the present invention, the beam targeting system may include a CCD or CMOS image acquisition device adapted to acquire images. Based on an analysis of the acquired video images, an object's/target's direction relative to the system (e.g. relative angles in the x and y planes) may be determined and the targeting system may issue a command or signal intended to cause the beam targeting optics to direct the output of the light source in the direction of the target and to illuminate the target/object. A light pulse of a fixed duration (e.g. 150 nanoseconds) may be used to determine the distance of the targeted object from the system. An optical receiver, which may either be part of the targeting system or which may be part of a common optical arrangement with the light source and scanning optics, may be used to receive reflections of the light pulse from the targeted object. By timing the period between the pulse's start and the optical receiver first registering or receiving a reflection of the light pulse from the object, the distance or range of the object from the system may be calculated.

The targeted object's position relative to the system (e.g. the object being at x, y, z coordinates, while the system may be defined as either the center or some other point in the coordinate space) may be determined using the relative direction and distance/ranging data acquired as described above. The targeted object's absolute position (e.g. longitude, latitude and altitude) may be determined by offsetting the system's absolute position, which may be determined with the aid of a GPS system, by the targeted object's position relative to the system. In accordance with further embodiments of the present invention, the targeted object's position relative to the system may be determined using the relative direction and distance/ranging data of a third object either moving or fixed. The position of the third object may be predetermined.

Turning now to Fig. 1, there are shown four aircrafts flying in formation, where each aircraft has a bi-directional optical communication link or channel with an adjacent aircraft. The last aircraft is shown to have a bi-directional communication link with a geo-stationary satellite. For each bi-directional link, an aircraft may have both a modulated light source with a targeting system and optics, and an optical receiver. In some embodiments of the present invention, there may also be a beacon somewhere in proximity to the optical receiver. It should be evident to one of ordinary skill in the art that any of the aircrafts would also be capable of maintaining a target optical link with a land or water based communication platform.

Turning now to Fig. 2, there is shown one possible embodiment of a directed optical transmitter according to some embodiments of the present invention. The light source may be a laser source. Laser sources and laser drivers, including laser diodes used for communications are well known in the art. Any laser source or laser driver presently known or to be devised in the future is applicable to the present invention.

Light from the light source may be modulated with a data signal by either modulating current to the light source or by using a light modulator adapted to modulate light leaving the light source. Modulated laser light sources or optical modulators are well known in the art and any presently known or to be devised in the future modulated laser light source or optical modulator is applicable to the present invention.

Additionally, an encoder (not shown), such as turbo encoder, for example, may be used to first encode a data signal and the encoded signal may be used to modulate light from the light source. Encoding may be used to introduce redundant bits into a bit stream. Encoders are well known in the art of communication. In some embodiment of the present invention, the light may be modulated within the light source. A light source driving signal may be derived from the data signal (e.g. laser driver or amplified gated or mixed with an encoded data signal) and may be used to drive a light or laser source such as a laser diode, thus removing the need to use an optical modulator. Techniques for modulating a light source, such as a laser source, are well known in the art. Any method of modulating a light source presently known or to be devised in the future is applicable to the present invention. The modulated light or laser beam may be directed by beam targeting optics to an optical receiver, such as the one shown in Fig. 3. A beam targeting optics block according to some embodiments of the present invention, for directing a light or laser beam towards a specific location or target, may include one ore more lenses (e.g. collimator), one or more mirrors with or without servos, and one or more piezoelectric elements. Laser beam targeting or scanning optics blocks are well known in the art and any presently known or to be devised in the future laser beam targeting or scanning optics block is applicable to the present invention.

The beam targeting optics block may be driven by a beam targeting control signal produced by a targeting and tracking system. The targeting and tracking system may include a video camera, CCD, CMOS or other optical input array or device. The video camera may provide an input signal to a computing device programmed to derive the location or direction of a specific object/target based on the input signal. The targeting and tracking system may derive an estimate of the location or direction of the object/target, such as the optical receiver of Fig. 3, or other target, and may produce a control signal intended to drive the beam targeting optics, such that a light or laser beam entering the targeting optics is directed to the estimated location of the optical receiver of Fig. 3. Targeting and tracking systems for targeting and tracking specific objects (not just the receiver of Fig. 3) are well known and any targeting and tracking system or systems presently known or to be devised in the future is applicable to the present invention. A general purposes targeting and tracking system may be adapted to target and track some object associated to the receiver of Fig. 3. For example, the object to be tracked may be either the receiver itself, or it may be a beacon somewhere in proximity to the receiver (e.g. surrounding the receiver). In some embodiments of the present invention, both the targeting system and the targeting optics may be adapted to direct a light beam in the direction of the receiver and also to cause the beam to scan back and forth, either in a raster pattern, or in some other pattern suitable for efficient coverage of a wide area where the receiver may be located. Various seamier methods and scanning elements are known. Scanning elements such as those used with bar-code scanners may be suitable as part of the present invention. These scanning elements often include one or more oscillating elements to which a reflective element is attached. As a laser beam is reflected from the reflective element which is oscillating due to the oscillation of the one or more oscillating elements to which it is attached, the reflected beam oscillates in a similar pattern to oscillation of the oscillating elements. The scanning of the laser beam may compensate for imprecise targeting of the beam and for sudden deviations in the relative positions of the transmitter and receiver, according to the present invention.

Turning now to Fig. 3, there is shown an optical receiver assembly according to some embodiments of the present invention. The receiver may have light collecting optics and filters to collect a modulated light or laser beam. Various optical filters may be used to filter out light of a frequency different from the frequency of the modulated light source. The collecting optics may be used to collect the modulated light beam and to focus it onto an optical transducer (e.g. photo diode, photo-multiplier-tube, etc.). The optical transducer may convert an optical signal into an electrical signal, which electrical signal may then be decoded or converted into a data signal by a decoder. Optical receivers and decoders are well known in the communication arts. The specific receiver, collecting optics and filters used may be selected based on the type of laser source to which they may be matched. The specific decoder used may be determined based on the type of modulation scheme used and the communication protocols used. It is foreseeable that a wireless communications link such as the one described above may use packetized data streams with a large amount of redundant packets and/or may use a encoder and decoder (e.g. Turbo, Viterbi, etc .), also with a large number of redundant bits.

A beacon, as shown in Fig. 3, may emit a signal (e.g. optical) to which the targeting system of Fig. 2 is tuned and tracks. The beacon may be in proximity to the receiver, or as in the embodiment shown in Fig. 3, the beacon may surround the receiver. As part of some embodiments of the present invention, as the targeting system targets and tracks the beacon, it may send a control signal to the targeting optics intended to direct the modulated light beam to the beacon and thus the receiver. In other embodiments of the present invention, the targeting system may be tuned to target some feature of the receiver itself.

Turning now to Fig. 4, there is shown a block diagram illustration of how a transmitter and receiver according to some embodiments of the present invention may interact to cause a data signal to be transmitted through an optical communication link. A modulated light or laser beam may be directed by a targeting system and targeting optics to an optical receiver assembly having collecting optics, filters, an optical transducer and a decoder. The receiver assembly may optionally have a targeting beacon to which the targeting system is tuned and tracks. Optionally, the targeting optics and system may have a scanning feature, which may cause the laser beam to scan in some sort of pattern around the desired target area, the area where the receiver's collecting optics may reside. Turning now to figure 5, there is a shown a directed optical transmitter according to some embodiment of the present invention used to determine the relative position of a target or object. According to some embodiments of the present invention, the targeting system may include a CCD or CMOS image acquisition device adapted to acquire images. Based on an analysis of the acquired video images, a target's direction relative to the targeting system (e.g. relative angles in the x and y planes) may be determined and the targeting system may issue a command or signal intended to direct the beam targeting optics in the direction of the target. A light pulse of a fixed duration (e.g. 150 nanoseconds) may be used to illuminate the target and to determine the distance of the targeted object from the system. An optical receiver, which may either be part of the targeting system or which may be part of a common optical arrangement with the light source and scanning optics (as shown in Fig. 5), may be used to receive reflections of the light pulse from the targeted object. By timing the period between the pulse's start and the optical receiver first registering or receiving the light pulse's reflection from the target, the distance or range of the object from the system may be calculated.

In the embodiment shown, common optical configuration may be used both for targeting an outbound laser beam on to an object, receiver or any other target, and for collecting the light reflected from the target and transmitting the collected light to a optical receiver. For example, an outbound laser beam produced by the laser source may pass through a beam splitter or through mirror with a pin hole (as is shown in Fig. 5), such that the path of the outbound laser beam is substantially uninterrupted. The outbound laser beam may enter the beam targeting and scanning optics block, where through a series of reflections and/or other optical manipulations the beam may be directed towards the target. A portion of the beam may be reflected back towards the beam targeting and scanning optics block. Thus, a portion of the reflected light may be collected by the beam targeting and scanning optics block, where through a series of reflections and/or other optical manipulations the reflected light may be directed towards the beam splitter or through the mirror with a pin hole. The beam splitter or the mirror with a pin hole may be configured to redirect the reflected light, for example by refracting or by reflecting the light, towards the optical receiver. It should be noted that the above description is purely exemplary in nature and that other configurations including these and other elements may be used to implement some embodiments of the present invention. According to some embodiments of the present invention, the targeted object's position relative to the system (e.g. the object being at x, y, z coordinates, while the system may be defined as either the center or some other point in the coordinate space) may be determined using the relative direction and distance/ranging data acquired as described above. The targeted object's absolute position (e.g. longitude, latitude and altitude) may be determined by offsetting the system's absolute position (e.g. determined with the aid of a GPS system) by the targeted object's position relative to the system.

While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

Claims

1. An electro-optic platform comprising: a modulated light source; a scanning optics block adapted to receive light from said light source; and a beam targeting system adapted to determine a relative direction of an object to be illuminated, said beam targeting also being adapted to produce a control signal intended to cause said scanning optics to direct light from said light source to said object.

2. The electro-optic platform according to claim 1, wherein said beam targeting system is adapted to determine a relative direction of a beacon.

3. The electro-optic platform according to claim 1, wherein said beam targeting system is adapted to determine a relative direction of an object having a predefined shape.

4. A method of illuminating an object, comprising: determining a relative direction of said object; and producing a control signal intended to direct light from a light source to said object.

5. The method of claim 4, wherein said determining comprises determining a relative direction of a beacon.

6. The method of claim 4, wherein said determining comprises determining a relative direction of an object having a predefined shape.