Patent Description:
When moving through a three-dimensional environment, a target detection system may encounter various interferrents, which may include aerosols and moving or non-moving objects. Conventional sensor systems, such as those for use on a projectile, often can distinguish between a target and other solid objects but encounter difficulty distinguishing between aerosols, such as those having particles spaced together in a volume, and a denser volume of a target. Such system also can be frustrated by reflections, such as from a liquid or other reflective surface, when imaging targets of a temperature different than a background, or when distinguishing between interlaid elements, such as a target within a smoke or cloud volume. Conventional sensor systems typically saturate or have increased noise in such situations and provide a premature signal due to awaiting for the sensor to indicate the attainment of a single threshold, such as an energy level of a returned beam of light.

<CIT> discloses a proximity fuze which generates a focussed beam of pulsed laser radiation. Reflected pulses are examined by a range gate and by a comparator which allows firing only if the pattern of reflected pulses matches one of a number of stored target profiles. The range gate passes only those pulses from targets within a required range bracket. An integrator passes only pulses which are of long enough duration to be consistent with reflection from a desired target.

<CIT> discloses a LADAR system including circuitry for generating an electrical signal with an optical signal detector using N discrete samples; a bank of M parallel sample/hold circuit unit cells individual ones of which operate with an associated sample/hold clock, where each sample/hold clock is shifted in time by a fixed or programmable amount relative to a sample/hold clock of an adjacent sample/hold circuit unit cell; and further includes circuitry for sequentially coupling a sampled value of the electrical signal from a first output of individual ones of at least some of the M parallel sample/hold circuit unit cells to an analog to digital converter circuit. Each of the M parallel sample/hold circuit unit cells has a second output for outputting a digital signal for indicating the state (low or high) during a time that the associated sample/hold clock allowing for time of arrival determination. The LADAR system further includes or is coupled to a signal processor for deriving an image of the object and a range to the object based on signals at the first and second outputs. Assuming an effective sample/hold circuit sampling rate of X samples per second, a sampling rate of each of the M parallel sample/hold circuit unit cells can be X/M samples per second.

The present disclosure provides a detection system that overcomes one or more of these deficiencies of conventional sensor systems. The detection system is not dependent on formation of an image in a 2D plane by an array of a plurality of pixels or on the attainment of one or more thresholds, and thus is not affected by saturation or a single false returned energy signature caused by an aerosol reflection, for example. Rather the detection system is configured to build a profile of the environment proximate the detection system based on a plurality of reflected energy signatures received at a single pixel array.

The present disclosure provides a detection system that utilizes high dynamic range, monolithically arranged, digital pixel sensors for situational awareness, targeting, tracking or locating. The detection system transmits a radially outwardly directed set of laser pulses into an environment, aspects of the pulses being reflected back by environmental elements to a single pixel array. The single pixel array scans volumetric space proximate the environment for profile characterization of the reflected aspects by the detection system in terms of intensity and multiplicity. The detection system is configured to compare this profile against a library of profiles of known environmental elements to distinguish between the environmental elements and a target. The detection system may be disposed about an outer periphery of a projectile for use in determining when the projectile is proximate the target for triggering an actionable element of the projectile, such as an initiator fuze for an explosive system.

According to one aspect, the present disclosure provides a detection system for analyzing an environment about the detection system during movement of the detection system along a flight path through the environment, the detection system comprising: a laser light assembly that transmits temporally spaced pulses of light outwardly from the detection system; an optical detector that receives photonic energy of the transmitted light reflected back towards the detection system by the environment and that converts the photonic energy to electrical energy; a charge storage architecture that receives and stores the converted electrical energy; a charge reading architecture that digitizes the electrical energy stored at the charge storage architecture and transmits data regarding an energy level of the stored energy, wherein the electrical energy is digitized in a plurality of samples per emission of each pulse of light from the laser light assembly; a controller that receives digitized data from the charge reading architecture and analyzes said data, wherein the controller compiles a profile of the environment about the detection system including the measurements of the electrical energy from the analyses versus the time elements, and compares the compiled profile against predetermined profiles of environmental elements to enable recognition of the environmental elements by the detection system, and wherein the controller is configured to output a target declaration signal upon recognition of a pre-determined environmental element; and wherein the detection system further includes a temporal filter tuned to provide a signal in response to a change in energy level received to facilitate detection of a leading edge of the signal released from the charge storage architecture.

The optical detector may be a single pixel of a <NUM>-by-<NUM> array.

At least the optical detector, the charge storage architecture, the charge reading architecture, and the controller may be monolithically arranged as a single integrated component.

The plurality of samples digitized per emission by the charge reading architecture may be at least tens of samples per emission.

The charge reading architecture may be configured such that a digitization speed of each sample of the plurality of samples is less than five nanoseconds.

The charge reading architecture may be configured to digitize each of the plurality of samples at least a factor of <NUM>,<NUM> times faster than the duration of an interval between signals sent by the controller to trigger subsequent emissions of light from the laser light assembly.

Each emission of the light transmitted by the laser light assembly may be directed perpendicularly outwardly from the direction of movement in a fan-shaped pulse.

The detection system may further include a memory that stores the predetermined profiles of environmental elements, the profiles including measurements of electrical energy received versus time of digitization along a respective flight path.

The laser light assembly may be configured to transmit the temporally spaced pulses of light in a direction transverse a direction of movement of the detection system through the environment.

According to another aspect, the present disclosure provides a movable projectile, comprising: a fuselage; a motor coupled to the fuselage for driving movement of the fuselage through an environment, the fuselage extending along a central longitudinal axis of the projectile; an actionable element for being activated upon proximity of the projectile to a target located within the environment; a projectile controller directing activation of the actionable element; and a target detector array including a plurality of detection systems according to the one aspect, communicatively coupled to the projectile controller and configured to detect the target and to output a signal to cause the activation of the actionable element upon the proximity of the projectile to the target, the detection systems positioned circumferentially about a periphery of the projectile and about the central longitudinal axis of the projectile, each of the detection systems wherein the respective controller is a detector controller that is configured to output the target declaration signal upon recognition of the target being the pre-determined environmental element, to cause the projectile controller to activate the actionable element.

The light transmitted by the respective laser light assemblies may be directed perpendicularly outwardly from the central longitudinal axis of the projectile.

The plurality of detection systems may be circumferentially positioned in an arrangement circumferentially spaced from one another to prevent overlap of the transmitted light pulses, which are fan-shaped light pulses, in a predefined space about the projectile.

The actionable element may be a warhead initiation fuze coupled to a warhead that is coupled to the fuselage.

The temporally spaced pulses of light may transit a radial area of space during each emission period of each discrete pulse of light; wherein a digitization speed of each sample of the plurality of samples may be less than five nanoseconds; and wherein the controller that receives digitized data from the charge reading architecture analyzes said data to determine proximity of the detection system to a pre-determined environmental element.

The controller may be configured during the analysis to compare said data against a plurality of pre-defined profiles including measurements of electrical energy received versus time of digitization along a respective flight path, wherein the controller may be configured to output a target declaration signal upon recognition of the pre-determined environmental element.

A digitization speed of each sample of the plurality of samples may be less than two nanoseconds.

The charge reading architecture may be configured to digitize <NUM> to <NUM> samples per emission period.

According to yet another aspect, the present disclosure provides a detection system for analyzing an environment about the detection system during movement of the detection system through the environment along a flight path, the detection system comprising: a laser light assembly that transmits temporally spaced fan-shaped pulses of light outwardly from the detection system; and a monolithically arranged optical circuit having a body including a single pixel of a <NUM>-by-<NUM> array, a charge storage well, a comparator or an A-to-D converter, and a controller, wherein the optical circuit is configured to receive photonic energy of the transmitted light reflected back towards the detection system by the environment and that converts the photonic energy to electrical energy, wherein the charge storage well receives and stores the converted electrical energy, and wherein the comparator or the A-to-D converter digitizes the electrical energy stored in the charge storage well and transmits data regarding the electrical energy level of the electrical energy received into the charge storage well; and wherein the controller is configured to compile a profile of the environment about the detection system including the measurements of the electrical energy from the analyses versus times of digitization along the flight path of the respective electrical energy and configured to compare the compiled profile against the predetermined profiles of environmental elements to enable recognition of the environmental elements by the detection system, and wherein the controller is configured to output a target declaration signal upon recognition of a pre-determined environmental element, and wherein the optical circuit includes a plurality of comparators each configured to provide a signal to the controller upon detection of a different electrical energy level at the energy storage well.

The annexed drawings, which are not necessarily to scale, show various aspects of the disclosure, some of which may be shown schematically.

The present invention provides a detection system for analyzing an environment about the detection system, such as during movement of the detection system through the environment. Likewise, the detection system may be stationary and detect environmental elements moving past the detection system.

The detection system generally is configured to transmit and receive pulses of energy for the purpose of compiling a profile of environmental elements, such as those being passed by a detection system in transit. The profiles are functions of intensity of energy received versus a time element, such as a time of digitization along a respective flight path, for example. Pulse energy received may include multiplicities of pulse signatures, and a plurality of pulses per energy emission may be analyzed in concert for developing the aforesaid profile, the detection system being configured to compare the profiles against a library of known profiles to distinguish between environmental elements and a target being hunted, for example. The detection system is configured to develop the profiles using single pixels, such as in a <NUM>-by-<NUM> array. Because of the profiling of energy levels and number of digitizations per energy emission, the detection system does not require spatial resolution or development of an image such as in a 2D or 3D array for analysis of the environment. The quantity of energy data received is not sufficient for purposes of mapping the environment proximate or around the detection system.

In addition to detecting targets, the detection system is configured to not false-trigger on non-target interferrents analyzed in the environment proximate the detection system. The detection system is capable of distinguishing airborne scattering media, including aerosols, from a denser target. The airborne scattering media may include dust, rain, snow, water vapor, fog, oil fog, exhaust, smoke, etc. Other interferrents can include chaff, flying animals, etc. Via calibration and training of a controller of the detection system, the detection system can recognize these interferrents and distinguish them from true targets. Due to differences in the time elements (such as digitization times), multiplicities, and energy levels of the returned pulses of targets and interferrents, the detection system also can detect the presence of a target inside an interferrent.

In an example, the detection system may be included in a projectile configured to travel at high speeds, such as a missile, for determining when the missile is proximate a target for the purpose of initiating an explosive fuse. The detection system may be used with a variety of projectiles, or alternatively with a flying object such as a high-speed drone or hypersonic UAV. In one example, the detection system may be used as an active optical target detector (AOTD) for proximity detection of targets that have not been impacted directly by a missile or other flying weapon, but which are still within lethal range. By detecting these targets, and triggering a warhead within this range, the target may be destroyed even if the missile misses its target. While the detection system is discussed herein with respect to such a projectile, it will be appreciated that the detection system also may be used as a stationary system, such as for determining when a target passes by or is approaching the detection system.

Generally, the detection system according to the present invention sweeps the space in proximity to the detection system by virtue of movement of one of the detection system or environmental elements in the space relative to one another, but typically with respect to a moving detection system. The sweeping is conducted via a plurality of pulses, which may be provided in the form of one or more, such as an array, of fan-shaped laser beams.

With reference now to <FIG>, a detection system <NUM> is schematically illustrated and includes a controller <NUM>, a transmitter assembly <NUM>, and a receiver assembly <NUM>.

It is appreciated that the schematic illustration is but one arrangement of components suitable for enabling distinguishing of a target from environmental elements proximate or disposed about the detection system <NUM>. Other arrangements may be suitable. Other arrangements may include additional or alternative components or may omit one or more components illustrated in <FIG>.

The illustrated transmitter assembly <NUM> includes a laser assembly <NUM> and a laser transmitter circuit assembly <NUM>. The laser assembly <NUM> includes a diode component <NUM>, also referred to as a laser light source <NUM>, which may be a laser diode or a diode pumped microchip assembly, for example, that is configured to emit a laser beam. The light may be provided having a red color, for example having a wavelength in the range of about <NUM> to about <NUM>, or about <NUM> to about <NUM>, or about <NUM>. Alternatively, the laser light source <NUM> may provide light having an ultraviolet color.

The laser light source <NUM> is configured to transmit temporally spaced pulses of light outwardly from the detection system <NUM>, via control of the controller <NUM>. For example, the laser light assembly <NUM> may be arranged to transmit laser light pulses <NUM> in a direction transverse a direction of movement of the detection system <NUM> through the surrounding environment, such as orthogonal to the direction of movement. In other embodiments, the laser light assembly <NUM> may be arranged to transmit laser light pulses <NUM> parallel to or in a direction of movement.

The controller <NUM> and laser assembly <NUM> are configured to emit pulses <NUM>, such as with a duration of about <NUM> nanosecond to about <NUM> nanoseconds for example, or such as about <NUM> nanoseconds. The controller <NUM> and the laser assembly <NUM> also are configured to control the pulse repetition period, or interval between the signals sent by the controller <NUM> to trigger subsequent emissions of light from the laser light assembly <NUM>. The pulse repetition interval may be in the range of about <NUM> microseconds (<NUM>,<NUM> nanoseconds) to about <NUM> microseconds (<NUM>,<NUM> nanoseconds), or about <NUM> microseconds (<NUM>,<NUM> nanoseconds) to about <NUM> microseconds (<NUM>,<NUM> nanoseconds), or about <NUM> microseconds (<NUM>,<NUM> nanoseconds).

The laser assembly <NUM> further includes light directing elements <NUM> for directing the light from the laser light source <NUM> into a fan-shaped beam <NUM>. The light initially transmitted from the laser light source <NUM> may be optically formed by any suitable light directing elements <NUM>. For example, a collimater or collimating lens <NUM> may initially collimate the initial beam of light, with the light then being directed to a spreader lens <NUM> to spread the collimated beam into the fan-shaped, <NUM>-degree section of light <NUM>. In this manner, the light is able to be directed towards about a quarter of the space disposed circumferentially about the detection system <NUM>. The laser light source <NUM> and the light directing elements <NUM> may be jointly configured to direct the beam <NUM> a distance of about <NUM> meters to about <NUM> meters, or about <NUM> meters to about <NUM> meters, or about <NUM> meters from the laser assembly <NUM>.

Turning briefly to <FIG>, the fan-shaped beam <NUM> is thus released from the laser assembly <NUM> with a much greater width dimension <NUM> than thickness dimension <NUM>. The laser assembly <NUM> is preferably arranged to provide the smallest dimension, the thickness dimension <NUM> of the fan-shaped beam <NUM>, aligned in the direction of movement <NUM> of the detection system <NUM> through the environment <NUM>. The fan-shaped beam <NUM> is thus aligned with the fan expanding angularly outwardly from the laser assembly <NUM> in a direction orthogonal to the direction of movement <NUM> of the detection system <NUM>, and also orthogonal to the transmission direction <NUM> of light transmitted directly outwardly from the laser light source <NUM>. The fan-shaped beam <NUM> defines a segment of light that preferably approximately covers <NUM>-degrees of space about the detection system <NUM>.

The laser transmitter circuit assembly <NUM> provides a portion of control of the laser assembly <NUM>. A laser diode driver <NUM> is coupled to the laser light source <NUM> to provide and control necessary current from a power source <NUM>, such as a battery coupled to the transmitter assembly <NUM>. The laser pulse may be initiated via control of the controller <NUM>.

A clock <NUM> of the controller <NUM> is coupled to the laser diode driver <NUM> for signaling initiation of emission of light from the laser light source <NUM>, which initiation may occur delayed from the initial triggers signal sent by the controller <NUM>. For example, the delay may be within a range of about <NUM> picosecond to about <NUM> picoseconds, or such as about <NUM> picoseconds, from receipt of direction from the controller <NUM>. The delay may be referred to as the trigger period, or period from receipt of the trigger signal until actual emission of light.

It will be appreciated that the power source <NUM> may power each of the receiver assembly <NUM> and controller <NUM>, or alternatively that a separate power source may be included or provided separate from the detection system <NUM>. Likewise, the power source <NUM> may be a part not integrated with, but instead separate from, the detection system <NUM>.

The controller <NUM> is further integrated with the laser transmitter circuit assembly <NUM> in that the controller <NUM> also may be coupled to a temperature controlling component of the laser transmitter circuit assembly <NUM>, such as a temperature compensated laser drive <NUM>. The temperature compensated laser drive <NUM> is configured to control the temperature of at least the laser assembly <NUM> of the transmitter assembly <NUM> and to maintain temperature within the specified limits. This control enables creation of pulses of light having equivalent wavelength, power, and consistency, regardless of temperature of the surrounding environment. The temperature compensated laser drive <NUM> may include one or both of a heater or thermos-electric cooler, for example. The clock <NUM> may be coupled to the temperature compensated laser drive <NUM> and upon recognition of the laser assembly <NUM> being at a pre-specified temperature, the clock <NUM> may send the signal to the laser diode driver <NUM> to initiate the respective laser pulse from the laser assembly <NUM>.

A sync <NUM> is coupled to the laser diode driver <NUM> to provide a signal to the controller <NUM> when the laser has been fired, ending the trigger period of delay, thus starting a counter for a propagation time interval related to analysis of photonic energy received back from the environment in response to the initiated, emitted laser pulse. For example, the sync <NUM> detects a portion of the initial emission and sends a signal to the controller <NUM> to start the counter.

The receiver assembly <NUM> is configured to receive one or more reflected pulses <NUM> of light reflected from the environment from the plurality of pulses <NUM> of light transmitted initially by the laser assembly <NUM> of the transmitter assembly <NUM>. Generally, the receiver assembly <NUM> contains optics <NUM> to collect light reflected by environmental elements irradiated by the laser emissions of the laser assembly <NUM> and to relay the received pulses <NUM> of light (one or more) to an optical detector <NUM> configured to work at the chosen laser wavelength, converting the incoming photonic energy to electronic form.

The optics <NUM> may include any suitable optical componentry configured to generate a photo-current in response to light impinging thereon, such as a photodiode known to those of ordinary skill in the art. The optics <NUM> are coupled to the optical detector <NUM> for transmitting received photonic energy to the optical detector <NUM>.

The optical detector <NUM>, also referred to as a detector, is preferably an individually acting, or single detector <NUM>, and preferably a single pixel cell in a <NUM>-by-<NUM> array. In this way, the single optical detector <NUM> is not combining input of one or more additional pixels that may be included in the respective detection system <NUM> to map a 2D or 3D image. Rather the detection system <NUM> is configured to individually analyze the received photonic energy from the single detector <NUM>. Specifically, the optical detector <NUM> is configured to receive and to convert the photonic energy received into electrical energy.

In other embodiments, additional single pixel, <NUM>-by-<NUM> arrays may be included in a single detection system, with each acting independently of one another.

The depicted individual optical detector <NUM> itself is coupled to additional architecture necessary to provide the functions of amplification, filtering and digitizing of the electronic signal converted by the optical detector <NUM>. In the preferred depicted embodiment of <FIG>, the optical detector <NUM> is integrated into a readout integrated circuit (ROIC) architecture <NUM> that provides the functions necessary to amplify, filter, and digitize the electronic signal in an integrated package. The integrated package of additional amplification, filtering, and digitization components may be integrated into one component <NUM> with the optical detector <NUM>, such as using semiconductor fabrication techniques.

Accordingly, the detection system <NUM> provides an integrated ROIC architecture <NUM>, also herein referred to as an optical circuit, that is in a class of pixel circuits called "digital pixels" or "in-pixel ADCs. " In this configuration, the digital pixel provides analog-to-digital conversion of the returned signals. Due to the close proximity of the electronic and photonic components, the colocation typically permits faster operating cycles. Particularly, the monolithic component or integrated ROIC architecture <NUM> allows for rapid digitization of electrical signals received as compared to, for example, arrays of increased size requiring alignment of respective clock edges to allow for accurate data analysis. Other technical advantages provided by aspects and embodiments of such digital pixels may include improved feasibility, dynamic range, cost, performance, noise performance, and power consumption for a given pixel size relative to conventional architectures, such as analog pixel optical receivers otherwise coupled to amplification, filtering and digitization components.

The ROIC architecture <NUM> is generally configured to accumulate charge converted from the optical detector <NUM>, to integrate the charge, and to produce a voltage over a given time interval, which is herein referred to as a pulse integration interval. The pulse integration interval is generally temporally defined at front end by the initiation of the laser pulse <NUM> from the laser assembly <NUM> as indicated by a digital counter <NUM> coupled to the optical detector <NUM>. A pulse integration interval may have a predefined end point from the initiation of the laser pulse <NUM>, for cutting off analysis of the received photonic energy, also as controlled by the digital counter <NUM>.

As will now be described in detail, the ROIC architecture <NUM> includes the receiver assembly <NUM> and the controller <NUM>. A charge storage circuit assembly <NUM> is provided to store and release charge of the converted electrical energy output by the optical detector <NUM>. A preamp circuit assembly <NUM> is provided to amplify and filter the electronic signal output by the receiver assembly <NUM>. A processor circuit assembly <NUM> includes the controller <NUM> and provides the quantization, digitization and logic components of the ROIC architecture <NUM> for controlling the compilation of the profiles of the environment disposed about the detection system <NUM> in view of the differences in the times, multiplicities, and energy levels of the returned pulses <NUM> from targets and interferrents in the environment.

Now with reference to the charge storage circuit assembly <NUM>, included is a charge storage architecture <NUM> and a charge release architecture <NUM>. The charge storage architecture <NUM> includes a capacitive component, such as a capacitor, also referred to as a storage well, that receives and stores the converted electrical energy received from the optical circuit <NUM> of the receiver assembly <NUM>. This well can be a deep well such as for storing about <NUM>,<NUM> electrons to about <NUM>,<NUM> electrons, or about <NUM>,<NUM> electrons, for example. The well may be shallow well for storing about <NUM> to about <NUM>,<NUM> electrons, or about <NUM>,<NUM> electrons, for example. Or, the well may have any suitable capacity such as in the range of about <NUM>,<NUM> electrons to about <NUM> electrons, or in the range of about <NUM>,<NUM> electrons to about <NUM>,<NUM> electrons, or about <NUM>,<NUM> electrons, for example.

In some embodiments, a plurality of wells may be coupled to the optical detector <NUM>, such as where the wells are each shallow storage wells that may be filled and released of charge more quickly than deep wells. The charge storage architecture <NUM> may be coupled to each of the optical detector <NUM> and a charge reading architecture <NUM> of the processor circuit assembly <NUM> such as by noise reducing components, such as a low noise MOSFET switch, which can be used to isolate the well.

The charge release architecture <NUM> includes suitable components, such as a MOSFET, for removing all or a portion of the charge accumulated in the charge storage architecture <NUM>. In this way, the effective amount of charge that is accumulated by the digital pixel/ROIC architecture <NUM>, and thus enabled to be analyzed over an integration interval, may be increased.

The preamp circuit assembly <NUM> includes a gain amplifier <NUM> for amplifying the electrical signal released from the charge storage circuit assembly <NUM> for allowing for more efficient analysis by the processor circuit assembly <NUM>. Also included is a filter <NUM> that may be tuned to provide a higher electrical signal value in response to a change of level to facilitate more precise time analysis of a leading edge of a signal received by the optical detector <NUM>. In one embodiment, the amplifier <NUM> and filter <NUM> may each be aspects of a transimpedance amplifier <NUM>, tuned to provide a signal in response to a change in energy level received to facilitate detection of a leading edge of the signal released from the charge storage architecture <NUM>.

The processor circuit assembly <NUM> receives the electrical signals from the charge storage circuit assembly <NUM> and the preamp circuit assembly <NUM>. Generally, the processor circuit assembly <NUM> is configured to control initiation of the transmitter assembly <NUM> and to process signal data received from the receiver assembly <NUM> via the charge storage circuit assembly <NUM> and/or the preamp circuit assembly <NUM>. The processor circuit assembly <NUM> includes a digitization element, such as a charge reading architecture <NUM>, a look gate <NUM>, and the controller <NUM>.

The charge reading architecture <NUM> is configured to digitize the electrical signal stored at the charge storage architecture <NUM> and to transmit data regarding the energy level and time element related to receipt of the energy level at the optical circuit <NUM> to the controller <NUM> for further analysis. The charge reading architecture <NUM> may include a reading element <NUM>, such as a comparator or an A to D converter. The comparator may have a fixed or programmable reference voltage. The charge reading architecture <NUM> is configured to detect the charge of the associated charge storage architecture <NUM> and to directly or indirectly cause the charge release architecture <NUM> to empty the respective well, such as by shorting or release of the energy stored therein. The charge reading architecture <NUM> also may include a digital memory controller for aiding in digitizing the respective electrical signals.

The detection system <NUM> may include a digital counter included in, or separate from, any of the aforementioned assemblies or circuits, for recording quantity of charge removals. In such case, the type of digital counter used to record charge removals can be of any logical variation, including binary, gray code, Linear-Feedback-Shift-Register (LFSR), or any other digital count circuit that can count charge removals. Furthermore, the relative sign of the charge removal can be plus or minus, relative to circuit ground, so a charge removal could be viewed as a charge addition in some cases.

The charge reading architecture <NUM> is configured to digitize a plurality of samples per emission of each pulse <NUM> of light from the laser light assembly <NUM>. The rapid digitization speed is enabled via the circuitry and monolithic nature of the ROIC architecture <NUM>. Each sample may be digitized over a time period of about <NUM> nanoseconds to about <NUM> nanosecond, or about <NUM> nanoseconds to about <NUM> nanosecond or about <NUM> nanosecond.

In one example, an integration interval begins at a time of actual emission of a pulse <NUM>, such as indicated by the sync <NUM>, and ends a predetermined time thereafter, defining a predetermined integration interval over time per each emission/pulse <NUM>. Such integration interval may have a length of time in the range of about <NUM> nanoseconds to about <NUM> nanoseconds, or about <NUM> nanoseconds to about <NUM> nanoseconds, or about <NUM> nanoseconds or about <NUM> nanoseconds, for example. Alternatively, the integration interval may be measured in terms of the number of samples digitized, where about <NUM> samples to about <NUM> samples are digitized per emission, or about <NUM> samples to about <NUM> samples, or about <NUM> samples, or about <NUM> samples. In one embodiment, where subsequent samples are digitized about each nanosecond, for example, the digitization frequency accordingly may be as high as about <NUM>.

Typically, the same integration interval length per emission or the same number of samples digitized per emission is utilized to allow for accurate comparison of the plurality of digitized samples over the flight path of the detection system <NUM>. Beyond such integration interval, useful data may not be obtained, and thus energy of and use of the ROIC architecture <NUM> may be wasted.

The controller <NUM> is coupled to each of the receiver assembly <NUM>, transmitter assembly <NUM> and charge reading architecture <NUM>. The controller <NUM> includes the clock <NUM>, a detection logic <NUM>, and in some embodiments also may include the charge reading architecture <NUM> integral therewith. The controller <NUM> may include a processor or any other suitable control hardware component such as an application specific integrated circuit, a programable logic device, a memory device containing instructions, or the like.

The controller <NUM>, also referred to as a detector controller <NUM>, serves various purposes. For example, the controller <NUM> includes the clock <NUM> that aids in control of the transmitter circuit assembly <NUM> to control initiation of the laser diode driver <NUM>. The controller <NUM> further includes the detection logic <NUM> that receives indication of initiation of the laser pulses from the laser assembly <NUM> via the look gate <NUM> of the processor circuit assembly <NUM>. The controller <NUM> includes an internal memory (not specifically shown, but which may be included in the detection logic <NUM>) that stores times of initiation of the pulses from the transmitter assembly <NUM>. Likewise, in that the controller <NUM> is configured to receive the data from the charge reading architecture <NUM>, the internal memory also may store such data.

From the stored data, the controller <NUM>, via the detection logic <NUM>, is configured to analyze the data related to transmission of pulses <NUM> and receipt of returned reflective pulses <NUM> a plurality of times per duration of each pulse <NUM> of light from the laser light source <NUM>. The controller <NUM> compiles a profile, or a plurality of profiles, of the environment about the detection system <NUM> including the measurements of the electrical energy from the charge reading architecture <NUM> versus respective time elements. The time elements may include the time of sample digitization along the flight path, allowing for accurate spatial recognition of the environmental elements. Such time of digitization may one of the predetermined sampling interval, a time of crossing of a predetermined energy threshold of a comparator of the charge reading architecture <NUM> as compared against the time of initiation of the respective pulse, and/or may include a time of release of or shorting of energy from a well <NUM> of the charge storage architecture <NUM>, such as where the charge reading architecture <NUM> or charge storage architecture <NUM> is configured to empty the charge storage architecture <NUM> upon maximum fill, for example.

In some embodiments, the controller <NUM> may be configured to continuously compile said profile. In other embodiments, the controller <NUM> may not continuously compile said profiles, but instead may compile at predetermined intervals, such as numerous times per second, or numerous times per emission of one or more laser pulses <NUM>, for example.

The controller <NUM> via the detection logic <NUM>, compares the compiled profiles against predetermined or stored profiles of environmental elements to enable recognition of the environmental elements by the detection system <NUM>. The stored profiles may be stored in a profile memory <NUM> that is a part of or separate from the detection system <NUM>. The stored profiles preferably include corresponding measurements of electrical energy signatures versus time elements.

Further, the controller <NUM> is configured to output a target declaration signal upon recognition of a pre-determined environmental element, such as a target. The target declaration signal may be output via wire or may be output wirelessly. Likewise, the controller <NUM> may access the library of stored profiles in a profile memory that is connected via wire or wireless means to the controller <NUM>.

In the case of respective wireless transmissions or data transfers, a transmission element (not shown) may be included in or separate from the processor circuit assembly <NUM>. The controller <NUM> may be configured to transmit data via any suitable network connection, such as cellular, WiFi, ethernet, Bluetooth, token ring, Zigbee, or the like.

Turning now to <FIG>, a method of analyzing an environment about the detection system <NUM> during movement of the detection system <NUM> through the environment is schematically illustrated. One of ordinary skill will recognize that such method also is applicable to use of a stationary detection system <NUM> analyzing passing environmental elements.

The method is illustrated as a series of blocks. However, the methodologies are not limited by the order of the blocks, as some blocks can occur in different orders or concurrently with other blocks from that shown or described, such as in parallel or in series with other blocks. Moreover, less than all of the illustrated blocks may be required to implement an example methodology. Furthermore, other methodologies can employ additional or alternative, non-illustrated blocks.

At block <NUM>, the controller <NUM> directs the laser diode driver <NUM> to produce a current to fire the laser assembly <NUM>. The transmitter assembly <NUM> is configured to fire the laser within picoseconds, such as within a range of about <NUM> picosecond to about <NUM> picoseconds, or such as about <NUM> picoseconds, from receipt of direction from the controller <NUM>. At block <NUM>, the trigger or delay period has ended, and the controller <NUM> receives indication from the sync <NUM> that the pulse <NUM> has been initiated, thereby starting the pulse duration. The pulse <NUM> may last on the order of about <NUM> nanosecond to about <NUM> nanoseconds for example, or such as about <NUM> nanoseconds.

Blocks <NUM> and <NUM> are repeated at pre-specified intervals. The controller <NUM> commands the respective transmitter assembly <NUM> to repeat the pulse <NUM> a predetermined number of times intervally spaced apart, such as according to the aforementioned pulse repetition interval with spacing between successive pulses <NUM> of a set of pulses being greater than or equal to the duration of any single pulse <NUM> and greater than the full sampling interval of the ROIC architecture <NUM>. The laser pulses <NUM> are temporally brief, as aforedescribed, on the order of a nanosecond or less in duration each, and thus the transit of the laser pulse <NUM> and the return reflection(s) <NUM> at the speed of light is much less than the time between each successive pulse <NUM> of a set of pulses <NUM>. It is noted that the pulse repetition interval may be between pulses <NUM> of the same detection system <NUM>, or in a target detector array <NUM> including a plurality of target detection systems <NUM>, the pulse repetition interval may be between pulses of different detection systems <NUM>, where at least one of the detection systems <NUM> is not fired at the same time as at least one other of the detection systems <NUM>.

In one embodiment, for example, where the charge reading architecture <NUM> is configured to digitize each of <NUM> samples over the predefined sampling interval, with each of the subsequent digitizations taking about <NUM> nanosecond, the complete digitizations or sampling interval may be on the order of about <NUM> nanoseconds. Comparatively, in the same embodiment, where the pulse repetition interval is <NUM>,<NUM> nanoseconds (<NUM> microseconds) for example, the charge reading architecture <NUM> is thus configured to digitize each of the samples a factor of <NUM>,<NUM> times faster than the duration of the pulse repetition interval. In other embodiments, the controller <NUM> and the charge reading architecture <NUM> may be configured such that the charge reading architecture <NUM> digitizes each of the samples a factor of about <NUM>,<NUM> to about <NUM>,<NUM> times faster than the pulse repetition interval, or about <NUM>,<NUM> time to about <NUM>,<NUM> times faster, or about <NUM>,<NUM> times faster.

In some examples, such as shown in <FIG>, where the detection system <NUM> includes a plurality of detection systems <NUM> spaced apart from one another, detection systems <NUM> adjacent one another may not be fired simultaneously to avoid cross-talk. Instead the respective controllers of each of the detection systems <NUM> may control the various detection systems <NUM> to fire in a succession, or depending on arrangement, for opposing detection systems <NUM> to fire simultaneously, with adjacent detection systems <NUM> not firing until firing is complete from the initial detection systems <NUM>.

At block <NUM>, the receiver assembly <NUM> receives reflected pulses <NUM> of light that have reflected off of elements in the environment, such as interferrents or a target. At block <NUM>, the optical detector <NUM> receives the photonic energy of the reflected pulses and converts the pulses into electrical energy signatures. Such signatures may have varying energy levels and may be received at various times. For example, laser light reflected off of moisture droplets may cause a plurality of temporally spaced apart returns of varying energy levels.

At block <NUM>, the converted electrical energy is received at one or more storage wells of the charge storage architecture <NUM>. At block <NUM>, the preamp circuit assembly <NUM> receives the electrical signals from the receiver assembly <NUM> and may provide a signal in response to a change in energy level received to facilitate detection of a leading edge of the signal released from the charge storage architecture <NUM>.

At block <NUM>, one or more of a comparator, an A-to-D converter or a digital memory controller of the charge reading architecture <NUM> digitizes the electrical signal stored at the charge storage architecture <NUM> and transmits data regarding the energy level and time element to the controller <NUM> for further analysis. In connection with block <NUM>, the charge reading architecture <NUM> may directly or indirectly cause the charge release architecture <NUM> to empty the respective well, such as by shorting or release of the energy stored therein.

Internal blocks <NUM>, <NUM> and <NUM> represent various approaches to measurement of electrical signals received at and stored in the charge storage architecture <NUM> by the charge reading architecture <NUM>. It will be appreciated that any of the first approach (block <NUM>), second approach (block <NUM>), and third approach (block <NUM>) may be used. Where multiple detection systems <NUM> are included in a target detector array <NUM>, one or more approaches may be used for different of the detection systems <NUM>, such as at different times, although it is preferred that at least one same approach be used for each of the detection systems <NUM>.

At block <NUM>, the first approach includes the use of one or more shallow wells <NUM>, such as aforedescribed. In this approach, a comparator <NUM> with a predetermined reference voltage detects the setpoint at the shallow charge well <NUM>. When the set point is exceeded, the charge release architecture <NUM> is caused to briefly short the well to reset the well, and a digital counter is incremented. At a predetermined interval basis, such as about every nanosecond for about a <NUM> nanosecond to about a <NUM> nanosecond interval, the controller <NUM> reads and records the count from the digital counter. The number of counts is utilized as energy level data transmitted to the controller <NUM> by the charge reading architecture <NUM>.

At block <NUM>, the second approach includes the use of multiple comparators <NUM> that are programmed to simultaneously detect charge at several predetermined levels of interest at the well <NUM> of the charge circuit assembly <NUM>. The comparators <NUM> may simultaneously digitize the electrical charge and transmit data to the controller <NUM> at a predetermined interval basis, such via the aforementioned sampling interval, such as about each nanosecond for a duration of about <NUM> to <NUM> nanoseconds, such as about <NUM> nanoseconds. The time of digitization of each comparator may be transmitted to the controller <NUM> as respective time elements.

At block <NUM>, the third approach includes the use of two or more deep storage wells <NUM> as aforedescribed. Instead of use of a comparator, the charge reading architecture additionally or alternatively includes a local A-to- D converters <NUM> configured to read and to cause discharge of the deep storage wells <NUM>, such as during the comparatively long time between laser pulses <NUM>, or across many pulses <NUM>. This approach requires parallel capacitive wells <NUM> of comparable size, switching between them so that reflected laser signal accumulation may be accomplished in an alternate well <NUM> while charge is read and digitized from at least one other well <NUM>. It is appreciated that an A-to-D convertor may operate at speeds slower than a comparator.

At block <NUM>, the detection logic element <NUM> of the controller <NUM> is configured to compile a profile of the environment, which may include one or more sub-profiles of environmental elements encountered, such as targets or interferrents. The profiles are functions of energy level of the one or more energy signatures received from each pulse transmitted and of time elements. The time elements may include time of receipt of the respective electrical energy at the optical circuit <NUM>, time of accumulation of one or more predetermined energy levels, or time of digitization by the charge reading architecture <NUM> for example. By comparing the compiled profile to known profiles, the controller <NUM> can determine the presence of a target, and can distinguish a target from interferrents, ensuring that the detection system <NUM> does not receive a false detection of a target.

In some embodiments, at least a part of the analysis step <NUM> may take place at another assembly or circuit where suitable, such as where a logic element is included elsewhere in the respective target detector <NUM>.

At block <NUM> the controller <NUM>, such as the detection logic element <NUM>, may be configured to compile new environmental profiles of interferrents, for example, not yet in the library accessed by the detection logic element <NUM>. Such new profiles may be stored in the internal memory of the controller <NUM>, or instead may be written to the external memory <NUM>.

At block <NUM>, the controller <NUM> outputs a target declaration signal upon detection of a known or predetermined target profile.

Turning now to <FIG>, a projectile <NUM> is shown including a target detector array <NUM> including a plurality of target detection systems <NUM> according to the aforementioned description of the detection system <NUM>. The projectile <NUM> depicted is a missile or rocket, although other projectiles may be suitable for use with the detection system <NUM>. The projectile <NUM> includes a fuselage <NUM> to which a motor <NUM>, such as a booster, is coupled for driving movement of the projectile <NUM> through an environment. The fuselage <NUM> extends longitudinally along a central longitudinal axis <NUM> between a forward nose cone <NUM> and the motor <NUM>.

The projectile <NUM> includes an actionable element <NUM>, such as a warhead initiation fuze coupled to an explosive warhead <NUM>, coupled to the fuselage <NUM>. A projectile controller <NUM> contained within the projectile <NUM> is configured to receive the target declaration signal from the detection system <NUM> and to communicate with the actionable element <NUM> to direct activation of the actionable element <NUM>, such as activating the initiation fuze. In other embodiments, the projectile controller <NUM> may be separate from the fuselage <NUM>, such as where the controller <NUM> communicates with a transmitter provided in place of the projectile controller <NUM> at the fuselage <NUM>.

The plurality of detection systems <NUM> are positioned circumferentially about a periphery <NUM> of the projectile <NUM> and about the central longitudinal axis <NUM> of the projectile <NUM>. Each of the detection systems <NUM> includes a laser light assembly that transmits temporally spaced fan-shaped pulses <NUM> of light outwardly from the respective detection system <NUM>. In the depicted embodiment, the detection systems <NUM> are arranged to emit the pulses <NUM> in a direction <NUM> transverse the central longitudinal axis <NUM> of the projectile <NUM>. The detection systems <NUM> may be otherwise arranged, such with at least one of the detection systems <NUM> arranged to emit the pulses <NUM> parallel to or in the direction of movement of the projectile <NUM>.

In the depicted embodiment, four detection systems <NUM> are included, and are equally circumferentially spaced about the periphery <NUM> of the projectile <NUM>, with each of the respective fan-shaped pulses <NUM> covering a section of about <NUM>-degrees of space circumferentially about the periphery <NUM>. The detection systems <NUM> are aligned to present each of the respective fan-shaped pulses <NUM> in a common plane <NUM> that orthogonally intersects the central longitudinal axis <NUM> of the projectile <NUM>. The circumferential spacing of the detection system <NUM> prevents overlap of the transmitted fan-shaped light pulses <NUM> in space about the projectile <NUM>. The space in which the pulses <NUM> do not overlap may have a diameter greater than or equal to a maximum outer diameter of the projectile <NUM>, such as including projections <NUM>, such as wings, fins, etc. In other embodiments, any number of detection systems <NUM> may be used, and may be otherwise arranged relative to one another where suitable.

The fan-shaped pulses <NUM> are thinner in the direction along the projectile flight path than in the common plane <NUM>. Together, the four respective fan-shaped pulses <NUM> cover a full <NUM>° circle circumferentially around the projectile. The respective detection systems <NUM> may be configured to extend each pulse <NUM> to a maximum lethality limit <NUM> of at least about <NUM> ft to about <NUM> ft, or about <NUM> ft to about <NUM> ft, or about <NUM> ft outwardly from the periphery <NUM> in the direction <NUM> orthogonal the axis <NUM>.

Each detection system <NUM> also includes an optical detector that receives photonic energy of the transmitted light reflected back towards the respective detection system <NUM> by the environment and that converts the photonic energy to electrical energy. A charge storage architecture receives and stores the converted electrical energy, and a charge reading architecture digitizes the electrical energy stored at the charge storage architecture and transmits data regarding an energy level of the stored energy to a detector controller. A memory onboard the projectile <NUM>, which may be a part of the detection system <NUM> or separate from the detection system <NUM>, is configured to store profiles of known environmental elements. In other embodiments, the memory storing said profiles may be disposed separately from the projectile <NUM> with the detector controller communicating wirelessly with the off-board memory.

The detector controller is configured to receive the data from the charge reading architecture and also to direct the respective detection systems <NUM> to initiate light pulsing at temporally distinct intervals from others of the target detectors. Each detection system <NUM> preferably includes a different respective detector controller, although in some embodiments two or more detection systems <NUM> may share a detector controller. When the respective detector controller determines recognition of a predetermined target <NUM>, such as depicted in <FIG>, the detector controller outputs a target declaration signal to the projectile controller <NUM>, thereby causing the projectile controller <NUM> to activate the actionable element <NUM>, and in the case of the illustrated projectile <NUM>, detonating the warhead <NUM>.

During flight, the respective detector controllers may command the respective transmitter assemblies to transmit pulses <NUM> in a particular order. While <FIG> illustrates each of the transmitter assemblies firing in unison, a preferred configuration includes each of the transmitter assemblies transmitting the respective set of pulses <NUM> in a continued succession, or where pairs of opposed transmitter assemblies opposite one another across the axis <NUM> are fired in unison, with the pairs firing in continued succession. The laser pulses <NUM> are temporally brief, as aforedescribed, on the order of about a nanosecond or less in duration each, and thus the transit of the laser pulse <NUM> and the return reflection at the speed of light is much less than the time between each successive pulse <NUM> of a set of pulses <NUM>.

Turning now to <FIG>, a schematic example of a flight path <NUM> of a projectile <NUM> is depicted to illustrate a use of the projectile <NUM> including the detection system <NUM> (<FIG>). The detection system <NUM> emits a plurality of pulses <NUM>, as aforementioned, and is configured to recognize environmental elements such as chaff <NUM> and clouds <NUM> as interferrents, while also recognizing a target <NUM> within an interferrent cloud <NUM>. The flight path <NUM> of <FIG> is graphically depicted in <FIG>, with (a) the target range of the chaff <NUM>, the aerosol clouds <NUM> and the target <NUM> from the projectile <NUM> and (b) the amplitude of the signals returned from the plurality of pulses <NUM> transmitted each graphed against the flight path <NUM> of the projectile <NUM>, i.e., against a distance of the projectile <NUM> from a starting point zero to a position in proximity with the target <NUM>.

In summary, and with reference to each of the aforementioned embodiments, the present disclosure provides a detection system <NUM>, <NUM> that utilizes high dynamic range, monolithically arranged, digital pixel sensors <NUM> for situational awareness, targeting, tracking or locating. The detection system <NUM>, <NUM> transmits a radially outwardly directed set of laser pulses <NUM>, <NUM> into an environment, aspects of the pulses <NUM>, <NUM> being reflected back by environmental elements to a single pixel array. The single pixel array scans volumetric space proximate the environment for profile characterization of the reflected aspects by the detection system <NUM>, <NUM> in terms of intensity and multiplicity. The detection system <NUM>, <NUM> is configured to compare this profile against a library of profiles of known environmental elements to distinguish between the environmental elements <NUM>, <NUM> and a target <NUM>. The detection system <NUM>, <NUM> may be disposed about an outer periphery <NUM> of a projectile <NUM> for use in determining when the projectile <NUM> is proximate the target <NUM> for triggering an actionable element <NUM> of the projectile <NUM>, such as an initiator fuze for an explosive system.

Claim 1:
A detection system (<NUM>, <NUM>) for analyzing an environment about the detection system during movement of the detection system along a flight path through the environment, the detection system comprising:
a laser light assembly (<NUM>) that transmits temporally spaced pulses of light outwardly from the detection system;
an optical detector (<NUM>) that receives photonic energy of the transmitted light reflected back towards the detection system by the environment and that converts the photonic energy to electrical energy;
a charge storage architecture (<NUM>) that receives and stores the converted electrical energy;
a charge reading architecture (<NUM>) that digitizes the electrical energy stored at the charge storage architecture and transmits data regarding an energy level of the stored energy, wherein the electrical energy is digitized in a plurality of samples per emission of each pulse of light from the laser light assembly;
a controller (<NUM>) that receives digitized data from the charge reading architecture and analyzes said data, wherein the controller compiles a profile of the environment about the detection system including the measurements of the electrical energy from the analyses versus the time elements, and compares the compiled profile against predetermined profiles of environmental elements to enable recognition of the environmental elements by the detection system, and wherein the controller is configured to output a target declaration signal upon recognition of a pre-determined environmental element; and
wherein the detection system further includes a temporal filter tuned to provide a signal in response to a change in energy level received to facilitate detection of a leading edge of the signal released from the charge storage architecture.