The present disclosure relates to directed navigation and more particularly to using an augmented semi-active laser seeker to provide initial altitude measurement and command denotation information for rounds.
Current guided munitions systems generally have limited weight and space allocations for imagers, which reduces their ability to locate and identify targets such as to only 1 to 2 Km. Given these weapons are launched at targets from 3 to 20 Km away, the current seekers are generally insufficient to navigate to the target. When using a designator as a means for in-flight navigation of the projectile to the target, current systems typically designate for the entire flight for a single round or projectile. This approach is time consuming, limits the rounds based on the designator resources, and results in rounds potentially firing every minute sequentially. For example, if the targeting platform needs to fire 10 rounds for the engagement, it may take 10 minutes to fire the 10th round. In a swarm boat situation, for example, it is desirable to fire 5 to 20 rounds is less than a minute in a rapid-fire sequence or at about 3 second intervals. This allows for the platform to dispense enough rounds and to move to another location and lessen risks to the platform. Any delays in firing increases the associated risks to equipment and personnel.
Wherefore it is an object of the present disclosure to overcome the above-mentioned shortcomings and drawbacks associated with the conventional object tracking and navigation systems.
One aspect of the present disclosure is a system for swarm navigation, comprising: a plurality of rounds, wherein the plurality of rounds comprises a leader round and one or more follower rounds, each round comprising: a diode configured to: generate pulsed energy to illuminate a target area comprising multiple targets; provide a transmitter portion of a laser range finder altimeter function; provide a transmitter portion of a proximity sensor for determining range to the target area comprising multiple targets; and provide a transmitter portion for a 3D LIDAR function for target aim refinement by combing data from a SAL seeker imager; the SAL seeker being configured to: receive pulsed energy reflected from the target area; determine angular bearing information if a follower round of any rounds in front of it; and provide a receiver function via an optical communications link for messages from the plurality of rounds; an imager having a FOV, the imager being configured to: use a horizon to determine an up and down reference; collect images of the target area; and capture images of multiple targets within the target area; and a processor configure to: correlate received pulsed energy reflected from the target area via the SAL seeker with images of the scene captured by the imager to form 3D images of multiple targets within the target area; determine a data set comprising: time from launch and estimated time to go to the target area; a number of targets in the target area; a spacing for multiple targets within the target area; a target cross range dispersion; a range from the round to the multiple targets in the target area; the round's position relative to remaining plurality of rounds; the round's current altitude; which target the leader round is engaging; a selected target based on the round's control authority and its range or time to go to the selected target, after removing previously selected targets (if the round is a follower) from the total targets in the target area; and transmit the data set to remaining rounds in the plurality of rounds via a communication link.
One embodiment of the system for swarm navigation using a follow the forward approach further comprises additional components including one or more navigation sensors, and IMUs.
Another embodiment of the system for swarm navigation using a follow the forward approach further comprises a barometer to maintain altitude once calibrated by the laser altimeter. In some cases, the system for swarm navigation further comprises a deployment mechanism for deploying the sensor suite from a radial viewing mode to a forward looking mode for use as a proximity sensor during terminal guidance.
In certain embodiments, the system for swarm navigation further comprises using 3D images for target ID and command detonation for a target type. In certain cases, the system for swarm navigation using a follow the forward approach further comprises use of a designator.
Another aspect of the present disclosure is a method for swarm navigation, comprising: providing a plurality of rounds, wherein the plurality of rounds comprises a leader round and one or more follower rounds, each round comprising: generating pulsed energy, via a diode, to illuminate a target area comprising multiple targets; providing a transmitter portion of a laser range finder altimeter function, via the diode; providing a transmitter portion of a proximity sensor, via the diode, for determining range to the target area comprising multiple targets; providing a transmitter portion for a 3D LIDAR function, via the diode, for target aim refinement by combing data from a SAL seeker imager; receiving pulsed energy reflected from the target area, via the SAL seeker; determining angular bearing information, via the SAL seeker, if a follower round of any rounds in front of it; providing a receiver function via an optical communications link for messages from the plurality of rounds; using a horizon to determine an up and down reference via an imager having a FOV; collecting images of the target area, via the SAL seeker; capturing images of multiple targets within the target area, via the SAL seeker; correlating received pulsed energy reflected from the target area via the SAL seeker with images of the scene captured by the imager to form 3D images of multiple targets within the target area, via a processor; determining, via the processor, a data set comprising: time from launch and estimated time to go to the target area; a number of targets in the target area; a spacing for multiple targets within the target area; a target cross range dispersion; a range from the round to the multiple targets in the target area; the round's position relative to remaining plurality of rounds; the round's current altitude; which target the leader round is engaging; and a selected target based on the round's control authority and its range or time to go to the selected target, after removing previously selected targets (if the round is a follower) from the total targets in the target area; and transmitting the data set to remaining rounds in the plurality of rounds via a communication link.
One embodiment of the method for swarm navigation using a follow the forward approach further comprises providing additional components including one or more navigation sensors, and IMUs. In some cases, the method for swarm navigation using a follow the forward approach further comprises providing a barometer to maintain altitude once calibrated by the laser altimeter.
Another embodiment of the method further comprises deploying the sensor suite from a radial viewing mode to a forward looking mode for use as a proximity sensor during terminal guidance. In some cases, the method for swarm navigation using a follow the forward approach further comprises using 3D images for target ID and command detonation for a target type. In certain embodiments, the method for swarm navigation further comprises using a designator.
Another aspect of the present disclosure is a method for swarm navigation, comprising: providing a plurality of rounds, wherein the plurality of rounds comprises a leader round and one or more follower rounds, each round comprising: generating pulsed energy, via a diode, to illuminate a target area comprising multiple targets; providing a transmitter portion of a laser range finder altimeter function, via the diode; providing a transmitter portion of a proximity sensor, via the diode, for determining range to the target area comprising multiple targets; providing a transmitter portion for a 3D LIDAR function, via the diode, for target aim refinement by combing data from a SAL seeker imager; receiving pulsed energy reflected from the target area, via the SAL seeker; determining angular bearing information, via the SAL seeker, if a follower round of any rounds in front of it; providing a receiver function via an optical communications link for messages from the plurality of rounds; using a horizon to determine an up and down reference via an imager having a FOV; collecting images of the target area, via the SAL seeker; capturing images of multiple targets within the target area, via the SAL seeker; correlating received pulsed energy reflected from the target area via the SAL seeker with images of the scene captured by the imager to form 3D images of multiple targets within the target area, via a processor; determining, via the processor, a data set; and transmitting the data set to remaining rounds in the plurality of rounds via a communication link.
One embodiment of the method is wherein the data set comprises: a time from launch and estimated time to go to the target area; a number of targets in the target area; a spacing for multiple targets within the target area; a target cross range dispersion; a range from the round to the multiple targets in the target area; the round's position relative to remaining plurality of rounds; the round's current altitude; which target the leader round is engaging; and a selected target based on the round's control authority and its range or time to go to the selected target, after removing previously selected targets (if the round is a follower) from the total targets in the target area.
Another embodiment of the method further comprises providing additional components including one or more navigation sensors, and IMUs. In some cases, the method further comprises providing a barometer to maintain altitude once calibrated by the laser altimeter.
Yet another embodiment if the method for swarm navigation further comprises deploying the sensor suite from a radial viewing mode to a forward looking mode for use as a proximity sensor during terminal guidance. In certain embodiments, the method further comprises using 3D images for target ID and command detonation for a target type.
These aspects of the disclosure are not meant to be exclusive and other features, aspects, and advantages of the present disclosure will be readily apparent to those of ordinary skill in the art when read in conjunction with the following description, appended claims, and accompanying drawings.
The foregoing and other objects, features, and advantages of the disclosure will be apparent from the following description of particular embodiments of the disclosure, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the disclosure.
One aspect of the present disclosure is a system comprising a plurality of rounds fired in a controlled sequence (weapons, missiles, guided rockets, free fall munitions, glide bombs, artillery, or the like) that act in concert. These rounds navigate to a plurality of targets using a forward most round's position relative to a target array. The forward most round is guided by a laser designator to engage a specific target within the target array. As the forward most round approaches the target array (multiple targets in a formation), an imager (LWIR, NIR, Visible, SWIR or MWIR) is used by the forward most round to characterize the array in terms of number of targets, relative position of each target to each other, classification/ID of the multiple targets, estimated target and forward most round range from the launch platform. In certain embodiments, the forward most round communicates this information back to the plurality of lagging munitions.
Certain embodiments of the system of the present disclosure comprise a rearward communications links (e.g., a 1 to 5 Hz rate) comprised of a coded laser/optical transmissions to provide all data gathered from a forward round to allow a next round in the sequence to determine which target it should select based on its range to target and control authority to ensure a high probability of hit. As the information is cascaded to each successive round, the transmitting round adds its target selection and its current location and altitude relative to the target formation allowing the following rounds to engage unselected targets and targets within their range.
A feature of the optical communications link is that each round has a SAL seeker, which can locates 1 to N rounds in its forward field of view (FOV). By knowing each forward round's trajectory and position within the trajectory, based on their target selections and coded communication messages, the ability of each round to navigate to an unselected target is done using an ad hoc, round constellation approach.
In one example, once the imager of the forward round acquires the target array, the use of a designator is no longer necessary and the plurality of rounds form a navigation network stretching from the launch platform to the target area. In one embodiment of the system, the rounds engage a land based threat. In this embodiment, the designator points to a ground position in the center of the target array. An imager on the round, such as the forward round, working with the semi-active laser seeker detects the laser return and correlates it to one or more pixels in the scene captured by the imager. That correlation allows the forward round to navigate to the ground position anointed by the laser using terrain navigation. To detect the plurality of targets, the round in one example needs to be closer to the target set given its limited optics. Once the target array has been detected, as described above, the forward round characterizes the engagement and provides the following rounds the necessary information for target selection and navigation to such target.
Augmenting a low cost semi-active laser seeker with a high powered laser diode to allow in one example the ability to function as an altimeter. For example, in one example the laser diode would be able to measure to about 2000 meters off the deck right after de-roll and prior to deployment of the sensor suite. In certain cases, the sensor suite is comprised of a low cost (LC) SAL (less than $1000), a high power laser diode (˜1000 watts—peak power) with beam forming optics. In a further example, a barometer is stowed in a radial view position. Once launched, and prior to the de-roll of the round, the laser diode activates and sends a series of pulses and the LCSAL receiver looks for a response from a ground direction such as in a 360 degree rotation pattern. From a typical helicopter launch (altitude 50 to 200 meters of the ground) as depicted in
After determining altitude, the sensor suite is rotated into a deployed position, i.e., looking forward. In the deployed position, the sensor suite in now employed as a proximity sensor as the round approaches the target. This allows the system to engage a target swarm or use pre-denotation prior to contact with the target for maximum warhead effects. Using an existing low cost semi-active laser (LCSAL), augmented with the high power diode (about 1000 watts), provides both an accurate azimuth/elevation (about 1 mrad) and target range, and a closure rate can be determined. This provides input into the round's terminal guidance processor for optimizing the rounds position (e.g., <1 meter) relative to the target.
In certain embodiments, the LCSAL receiver is responsible for receiving proximity information to the target swarm, communications from rounds in its forward view, and designator reflections from the targets deployed in the particular engagement. In one example, the series of pulses from the rearward facing high power laser diode for each round can be managed with time separation, or the like to distinguish the rounds. The designator, if present, is on a predetermined time schedule known to the round(s) inflight (typically a pulse at a 20 Hz rate). In one example, the communications between the rounds is an ad-hoc network with a leader-flower approach. The leader round would set a time relative update rate (such as 1 Hz) and then the follower(s) would cascade the communications messaging accordingly. For example, a 200 BIT message containing current positon, target grouping/dispersion information, target selection and position in the rounds group would be relayed. The proximity ranging and sensor fusing would be local to each round with its unique code, e.g. PRI coding, to eliminate crosstalk among the rounds.
As an example to explain the communications processing, in one example a pulse density of 20 designator pulses per second is used to control the lead round for 20 pulsed/second. Coupled with a 200 pulse communications message produces 2000 pulses (200 messages*10 rounds) and proximity ranging at 20 Hz for each round for additional 2000 pulses/second (20 Hz*10 weapons). The last round in flight could potentially see 4200 pulses, where 20 are from a designator, 2000 are communications messages and 2000 are for command detonation. In some cases, each pulse occupies 20 nanoseconds, only 0.0084% of the time base is consumed (i.e. 1/(20 nanoseconds*the 4200 pulse count per second in % time). In this situation, the likelihood of crosstalk is remote (e.g., 2 pulses at the same time is only 0.0084% of the time or once per about every 3.3 hours) and PRI sorting methods can adequately decode the communications messages and update the navigation/guidance for the each of the rounds to within about <1 meter remaining to the target's location.
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Current systems require 45 to 60 seconds per round to launch for a total of 1140 seconds (for 19 rounds). In contrast, the present disclosure provides for emptying a canister (of 19 rounds) in a single pass in <100 seconds. In one embodiment, it takes about 40 seconds to aim the first round, and each of the remaining 19 units are launched in 3 second intervals thereafter.
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Current solutions tend to use RF, which requires an additional RF receiver component. In contrast, the low cost semi-active laser seeker of the present disclosure can provide both a designation function and a communications receiver function with the added benefit of determining a direction of arrival for signal from the transmitting round (located in front of a receiving round) thus allowing in flight navigation of the follower round using a follow the leader approach. In one embodiment, the seeker has a 20° to 30° FOV coverage, using a high power pulsed diode of about 100 watts, about a 500 nanosecond pulse, at about 5 to 10 KHz, and about a 200 bit message. The seeker can provide the range to target group, cross range spread, the number of targets, the spacing of targets within the group, all for use in mapping trajectories for the members of the swarm. This allows each member to message which target that member is engaging, its position relative to the group, and its current altitude, all at about a 2 to 5 Hz Bit rate. The low cost semi-active laser (LCSAL) seeker therefore can provide a designator location, a communications link, and /message and bearing information of the round in front of it.
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The computer readable medium as described herein can be a data storage device, or unit such as a magnetic disk, magneto-optical disk, an optical disk, or a flash drive. Further, it will be appreciated that the term “memory” herein is intended to include various types of suitable data storage media, whether permanent or temporary, such as transitory electronic memories, non-transitory computer-readable medium and/or computer-writable medium.
It will be appreciated from the above that the invention may be implemented as computer software, which may be supplied on a storage medium or via a transmission medium such as a local-area network or a wide-area network, such as the Internet. It is to be further understood that, because some of the constituent system components and method steps depicted in the accompanying Figures can be implemented in software, the actual connections between the systems components (or the process steps) may differ depending upon the manner in which the present invention is programmed. Given the teachings of the present invention provided herein, one of ordinary skill in the related art will be able to contemplate these and similar implementations or configurations of the present invention.
It is to be understood that the present invention can be implemented in various forms of hardware, software, firmware, special purpose processes, or a combination thereof. In one embodiment, the present invention can be implemented in software as an application program tangible embodied on a computer readable program storage device. The application program can be uploaded to, and executed by, a machine comprising any suitable architecture.
While various embodiments of the present invention have been described in detail, it is apparent that various modifications and alterations of those embodiments will occur to and be readily apparent to those skilled in the art. However, it is to be expressly understood that such modifications and alterations are within the scope and spirit of the present invention, as set forth in the appended claims. Further, the invention(s) described herein is capable of other embodiments and of being practiced or of being carried out in various other related ways. In addition, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having,” and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items while only the terms “consisting of” and “consisting only of” are to be construed in a limitative sense.
The foregoing description of the embodiments of the present disclosure has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the present disclosure to the precise form disclosed. Many modifications and variations are possible in light of this disclosure. It is intended that the scope of the present disclosure be limited not by this detailed description, but rather by the claims appended hereto.
A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the scope of the disclosure. Although operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results.
While the principles of the disclosure have been described herein, it is to be understood by those skilled in the art that this description is made only by way of example and not as a limitation as to the scope of the disclosure. Other embodiments are contemplated within the scope of the present disclosure in addition to the exemplary embodiments shown and described herein. Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present disclosure.