Claims:We claim:

1. A method (600) for platform positioning in a network of tracker misleading systems (TMS), the method comprising:
calibrating a plurality of electro-mechanical systems of TMS coupled in the network for determining home position of each platform in the network of TMS’s by a main control system (610);
initiating a static and dynamic inertial sensing of the plurality of electro-mechanical systems in the network of TMS’s and receiving the inertial sensing times by each platform of the network of TMS’s (620);
calculating an electrical equivalent of network inertia of each platform of the network of TMS’s and predicting an offset value from the received static and dynamic inertia times based on the difference of value between a current position and an intended position for synchronized platform positioning (630);
creating a TDMA time slot structure for all the available TMS in the network during calibration and maintaining a closed loop using TDMA timing slots (640); and
providing a command to respective TMS by the main control system for platform positioning as per TDMA time slot created to place the platform in a required direction (650).

2. The method as claimed in claim 1, further comprising receiving an external trigger by the main control system for positioning respective platform of the TMS’s in a respective direction from an external sensor computing unit.

3. The method as claimed in claim 1, further comprising dynamically adjusting the TDMA time slots for all the TMS’s joining or leaving the network.

4. The method as claimed in claim 1, further comprising maintaining an individual inertial sensing offset for all delays associated with all the Tracker Misleading systems of the network and compensating the delay in the command to the respective Tracker Misleading system’s for platform positioning and receiving the response within a guard time by adjusting the TDMA time slots created for each Tracker Misleading system’s.

5. The method as claimed in claim 1, wherein the main control system and the individual TMS’s remain in closed feedback loop such that each Tracker Misleading systems (TMS) responds only during time slots when main control systems commands the individual Tracker Misleading systems.

6. The method as claimed in claim 1, wherein the method for platform positioning of each TMS comprises:
calibrating a home position of the platform with respect to true north by each TMS based on the command from the main control system;
measuring a static and dynamic inertial sensing of the plurality of electro-mechanical systems of the platform till the calibration process of homing position is complete, by an inertial sensing circuit of each TMS;
calculating an electrical equivalent of inertia times of the platform and offset value for platform positioning by the inertial sensing circuit of each TMS;
estimating and predicting an encoder count based on the calculated electrical equivalent and the intended electrical equivalent for stationary, accelerating, decelerating, and braking systems by the inertial sensing circuit and communicating the same to the main control system; and
positioning the platform by respective TMS in a required direction, when the command is received from the main control system for positioning the platform.

7. The method as claimed in claim 1 and 6, wherein measuring the static and dynamic inertial sensing of the plurality of electro-mechanical systems of TMS comprises measuring inertial time offset of the electro-mechanical system when the system is stationary, accelerating, decelerating, braking, etc.

8. The method as claimed in claim 1 and 6, further comprising capturing inertia times of plurality of electro-mechanical systems of TMS by the inertial sensing circuit of each Tracker Misleading system, converting the sensed/captured inertial times into equivalent electrical pulses and communicate the captured delays to main/master control system in a periodic interval.

9. The method as claimed in claim 1 and 6, further comprising sensing a mechanical alignment by the inertial sensing circuit of each Tracker Misleading system and communicate the sensing delays to main/master control system in a periodic interval as health status.

10. The method as claimed in claim 1 and 6, wherein sensing a electrical circuitry comprising DAC, Op-Amp MOSFETS and electrical energizing circuitry for servo drive mechanism in transmit side, and encoder and ADC in receiver side by the inertial sensing circuit of each Tracker Misleading system and communicate the sensing delays to main/master control system in a periodic interval.

11. The method as claimed in claim 6, further comprising inertia sensing for azimuth and elevation simultaneously while positioning the platform.

12. The method as claimed in claim 1 and 6, wherein the calculated offset value is updated for all commands for platform positioning.

13. The method as claimed in claim 6, wherein measuring the static and dynamic inertial sensing comprising:
generating and applying a required voltage for a servo system of the TMS via DAC;
amplifying the generated voltage by an operational amplifier and providing the amplified voltage to the servo system for moving the platform of the TMS;
capturing an electromechanical inertia of the TMS and converting all the captured electromechanical inertia times of the TMS into equivalent encoder pulse count by an encoder with respect to the full scale range of DAC (Digital to Analog Converter) chosen;
sampling the encoder pulse count with a very high sampling clock;
calculating and storing the offset difference of clock pulse counts; and
providing the encoded pulse count of the TMS to a FPGA/CPU for mapping offset to corresponding value DAC full scale voltage, to maintain the inertia sensing information and offsets for the platform of the TMS.

14. A system for platform positioning in a network of tracker misleading systems (TMS), the system comprising a processing unit configured to perform the steps:
calibrating a plurality of electro-mechanical systems of TMS coupled in the network for determining home position of each platform in the network of TMS’s by a main control system;
initiating a static and dynamic inertial sensing of the plurality of electro-mechanical systems in the network of TMS’s and receiving the inertial sensing times by each platform of the network of TMS’s;
calculating an electrical equivalent of network inertia of each platform of the network of TMS’s and predicting an offset value from the received static and dynamic inertia times based on the difference of value between a current position and an intended position for synchronized platform positioning;
creating a TDMA time slot structure for all the available TMS in the network during calibration and maintaining a closed loop using TDMA timing slots; and
providing a command to respective TMS by the main control system for platform positioning as per TDMA time slot created to place the platform in a required direction.

15. A system for platform positioning of each TMS, the system comprising a processing unit configured to perform the steps:
calibrating a home position of the platform with respect to true north by each TMS based on the command from the main control system;
measuring a static and dynamic inertial sensing of the plurality of electro-mechanical systems of the platform till the calibration process of homing position is complete, by an inertial sensing circuit of each TMS;
measuring a static and dynamic inertial sensing of the plurality of electro-mechanical systems of the platform till the calibration process of homing position is complete, by an inertial sensing circuit of each TMS;
calculating an electrical equivalent of inertia time of the platform and offset value for platform positioning by the inertial sensing circuit of each TMS;
estimating and predicting an encoder count based on the calculated electrical equivalent and the intended electrical equivalent for stationary, accelerating, decelerating, and braking systems by the inertial sensing circuit and communicating the same to the main control system; and
positioning the platform by respective TMS in a required direction, when the command is received from the main control system for positioning the platform.

Dated this 25th January, 2021

FOR BHARAT ELECTRONICS LIMITED
(By their Agent)

D. MANOJ KUMAR (IN/PA-2110)
KRISHNA & SAURASTRI ASSOCIATES LLP
, Description:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)

A METHOD AND SYSTEM FOR ACCURATE AND JERK FREE PLATFORM POSITIONING IN A NETWORK OF TRACKER MISLEADING SYSTEMS

BHARAT ELECTRONICS LIMITED
WITH ADDRESS:
OUTER RING ROAD, NAGAVARA, BANGALORE 560045, KARNATAKA, INDIA

THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention mainly relates to a tracker misleading systems and methods and more particularly to a method and system for an accurate and jerk free platform positioning in a network of tracker misleading systems.

BACKGROUND OF THE INVENTION

[0002] Tracker Misleading Systems is a system which protects a mission critical equipment by misleading an incoming threat i.e. projectile. Generally, a plurality of TMS mounted on the mission critical equipment which is primarily used to dispense chaff in different directions controlled centrally from a main system and connected physically using fiber optic cable links running over several meter to kms ranges.
[0003] The TMSs are located at different physical locations whose individual servo systems are being controlled locally and all TMS are remotely monitored from a main control system wherein all the elements are networked. The physical link may be as far as 1 to 2 Kms which are primarily connected using fiber optic cables. The remote TMS is a chaff dispenser based on the command received from the main or master control system and chaff can be dispensed to varying distances depending upon the control and command from main control system, like Short range, Mid-range and Long Range. An appropriate firing electrical circuitry gets energized based on control from main control system. These commands are sent with a suitable protocol from main control system to remote TMS for necessary action. The platform of TMS carries heavy load of several 100s of kilo grams of metal body. The whole network of TMS comprises electronic circuit with op-amp, DAC, MOSFETs etc., and electrical circuits with servo mechanism and actual heavy platform with chaff dispenser which offers lot of inertia in rotating the platform.
[0004] In an example, wherein multiple TMSs located physically at various places are networked and controlled from a master or main control system. The master control system provides the command to individual TMS based on incoming threat as read by other sensors on board the mission critical system like Radar, Electro Optic systems etc. The individual remote TMSs which are attached to servo systems, receives the commands from main system and does accurate platform positioning to release chaffs in time synchronized manner.
[0005] One of the prior arts discloses a method and apparatus for adjusting a targeting solution of a weapon system, wherein the system fires a projectile at a target which is a location device. Based on notification received about the impact location, of already fired target, targeting location of the next target will be adjusted. It is an active system wherein feedback is available based on GPS location.
[0006] Another prior art discloses a stabilization mount system for cameras, sensors and weapons. This prior art is about stabilization of payload such as cameras, sensors and weapons on moving vehicles. The stabilization mechanical mount system is controlled manually in some modes and uses machine to control automatically in some modes.
[0007] Further prior art discloses a complete method for protecting ships against terminal homing phase-guiding missiles provided with a target data analysis system, and also apparatus for implementing the said method. Incoming threats trajectory is estimated using a system. The detected sensor data is transmitted to a Tracker Misleading calculator through a network consisting of all elements such that to controls decoy launcher and generate decoy pattern.
[0008] From the above systems and methods, achieving accurate platform positioning is very challenging and more particularly when there are mechanical mounting misalignments. With inaccurate platform positioning, the performance of the whole system degrades, when chaff needs to be dispensed for a very long distance. The remote TMS and servo systems attached to those TMS respond with varying delays when operating in a network consisting of many other elements. Further, synchronization of various TMSs while checking and polling the health status of all the TMSs, wherein joining times and leaving times of the TMS into and from the network are random, is challenging which can be catastrophic in case of any eventuality.
[0009] Conventional platform positioning systems operate and adopt methods wherein the movement of platform is done in steps based on the error between placed and intended positions. Also, platforms with mechanical errors, provides unintended shifts in elevation when moved in azimuth direction and vice versa. To achieve overall intended platform positions, such systems usually move in azimuth and elevation, in steps, consuming more time whereas it becomes critical in Tracker Misleading systems.
[0010] Therefore, there is a need in the art with a method and system for an accurate and jerk free platform positioning in a network of tracker misleading systems to solve the above mentioned limitations.

SUMMARY OF THE INVENTION

[0011] An aspect of the present invention is to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below.
[0012] Accordingly, in one aspect of the present invention relates to a method (600) for platform positioning in a network of tracker misleading systems (TMS), the method comprising: calibrating a plurality of electro-mechanical systems of TMS coupled in the network for determining home position of each platform in the network of TMS’s by a main control system (610), initiating a static and dynamic inertial sensing of the plurality of electro-mechanical systems in the network of TMS’s and receiving the inertial sensing times by each platform of the network of TMS’s (620), calculating an electrical equivalent of network inertia of each platform of the network of TMS’s and predicting an offset value from the received static and dynamic inertia times based on the difference of value between a current position and an intended position for synchronized platform positioning (630), creating a TDMA time slot structure for all the available TMS in the network during calibration and maintaining a closed loop using TDMA timing slots (640) and providing a command to respective TMS by the main control system for platform positioning as per TDMA time slot created to place the platform in a required direction (650).

[0013] Another aspect of the preset invention relates to a system for platform positioning in a network of tracker misleading systems (TMS), the system comprising a processing unit configured to perform the steps: calibrating a plurality of electro-mechanical systems of TMS coupled in the network for determining home position of each platform in the network of TMS’s by a main control system, initiating a static and dynamic inertial sensing of the plurality of electro-mechanical systems in the network of TMS’s and receiving the inertial sensing times by each platform of the network of TMS’s, calculating an electrical equivalent of network inertia of each platform of the network of TMS’s and predicting an offset value from the received static and dynamic inertia times based on the difference of value between a current position and an intended position for synchronized platform positioning, creating a TDMA time slot structure for all the available TMS in the network during calibration and maintaining a closed loop using TDMA timing slots and providing a command to respective TMS by the main control system for platform positioning as per TDMA time slot created to place the platform in a required direction.
[0014] Further aspect of the preset invention relates to a system for platform positioning of each TMS, the system comprising a processing unit configured to perform the steps: calibrating a home position of the platform with respect to true north by each TMS based on the command from the main control system, measuring a static and dynamic inertial sensing of the plurality of electro-mechanical systems of the platform till the calibration process of homing position is complete, by an inertial sensing circuit of each TMS, measuring a static and dynamic inertial sensing of the plurality of electro-mechanical systems of the platform till the calibration process of homing position is complete, by an inertial sensing circuit of each TMS, calculating an electrical equivalent of inertia time of the platform and offset value for platform positioning by the inertial sensing circuit of each TMS, estimating and predicting an encoder count based on the calculated electrical equivalent and the intended electrical equivalent for stationary, accelerating, decelerating, and braking systems by the inertial sensing circuit and communicating the same to the main control system and positioning the platform by respective TMS in a required direction, when the command is received from the main control system for positioning the platform.
[0015] Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
[0016] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and modules.
[0017] Figure 1 shows an overall system block diagram of Network of Tracker Misleading System according to an exemplary implementation of the present invention.
[0018] Figure 2 shows a block diagram of remote tracker misleading system according to an exemplary implementation of the present invention.
[0019] Figure 3 shows a block diagram of inertial sensing circuit for Remote Tracker Misleading System for sensing the heavy loaded platform according to an exemplary implementation of the present invention.
[0020] Figure 4 shows flowchart of steps for closed loop control in Main Control System according to an exemplary implementation of the present invention.
[0021] Figure 5 shows a flowchart of steps for closed loop control in Remote Tracker Misleading System according to an exemplary implementation of the present invention.
[0022] Figure 6 shows a method for platform positioning in a network of tracker misleading systems (TMS) according to an exemplary implementation of the present invention.
[0023] It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative methods embodying the principles of the present disclosure. Similarly, it will be appreciated that any flow charts, flow diagrams, and the like represent various processes which may be substantially represented in computer readable medium and so executed by a computing device or processor, whether or not such computing device or processor is explicitly shown.
DETAILED DESCRIPTION OF THE INVENTION
[0024] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
[0025] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
[0026] It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces.
[0027] By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.
[0028] Figures discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way that would limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged communications system. The terms used to describe various embodiments are exemplary. It should be understood that these are provided to merely aid the understanding of the description, and that their use and definitions in no way limit the scope of the invention. Terms first, second, and the like are used to differentiate between objects having the same terminology and are in no way intended to represent a chronological order, unless where explicitly stated otherwise. A set is defined as a non-empty set including at least one element.
[0029] In the following description, for purpose of explanation, specific details are set forth in order to provide an understanding of the present disclosure. It will be apparent, however, to one skilled in the art that the present disclosure may be practiced without these details. One skilled in the art will recognize that embodiments of the present disclosure, some of which are described below, may be incorporated into a number of systems.
[0030] However, the systems and methods are not limited to the specific embodiments described herein. Further, structures and devices shown in the figures are illustrative of exemplary embodiments of the presently disclosure and are meant to avoid obscuring of the presently disclosure.
[0031] The various embodiments of the present invention describe about a method and system for accurate and jerk free platform positioning in a network of tracker misleading systems. The tracker misleading system is a mechanism which releases chaff, to protect, mission critical system being tracked against incoming threat. The Tracker Misleading Systems (TMS) need quick platform positioning with very high accuracy, particularly when they are operated from a remote location in a network. Normally, different Tracker Misleading systems respond with varying delays of inertia because of heavy loads attached, along with associated network delays when installed at distant locations.
[0032] The present invention method and system is for measuring inertia of electronic, electrical and mechanical systems of all available TMSs in the network, achieves accurate positioning of platforms of all individual TMS overcoming varying time delay responses, addresses the mechanical manufacture and mounting misalignments of heavy platform in TMS.
[0033] The present invention method and system creates a closed loop configuration for individual Tracker Misleading systems with their respective loaded servo platforms in azimuth and elevation directions and an overall closed loop configuration with a master or main control system in a network with TDMA slotted structure. The method dynamically adjusts the timing slots for all TMS elements joining or leaving network, helps achieve jerk free and accurate platform positioning in azimuth and elevation directions.
[0034] In one embodiment, the method and system achieves accurate positioning of a loaded platform, wherein the loaded platform is attached to a Tracker Misleading System used for protecting a mission critical system by releasing chaff, a Load of 100Kgs or more is driven by electrical motors energized by servo drive of Tracker Misleading System
[0035] In one embodiment, one or more Tracker Misleading System are operating in a network being controlled from a distance by a main control system.
[0036] In one embodiment, the method and system perform inertia sensing for the whole electromechanical system using the circuit comprising Analog to Digital Converter and Digital to Analog Converters which are performed continuously during operation.
[0037] In one embodiment, the main control system creates TDMA time slot structure for all Tracker Misleading Systems and maintains a closed loop, the tracker misleading system creates a closed loop with platform by sensing inertia of the whole system. The method provides a jerk free positioning of platform, overcomes accuracy errors due to mechanical mounting misalignments and gear ratio errors.
[0038] In one embodiment, the method and system comprising: performing inertia sensing for all delays associated with electrical circuitry comprising DAC, Op-Amp, MOSFETS and Electrical Energizing circuitry for servo drive mechanism in transmit side, encoder and ADC in receiver side for attached whole electromechanical system of heavy loaded platform and performing inertia sensing for electromechanical system during calibration and positioning when platform is stationary, accelerating, decelerating and braking. Further, the method and system comprising: measuring inertial time offset for heavy loaded platform along with associated electro mechanical system using DAC and ADC of equal bit resolution, feeding jitter and skew free synchronized clock to ADC, DAC and FPGA, wherein FPGA is to generate voltage for servo mechanism and ADC with high sampling clock is to sample encoder reading.
[0039] In one embodiment, measuring inertia time for stationary system comprising: applying a fractional value of full scale DAC voltage after releasing brake for the system, reading encoder and averaging over number of clock cycles, computing the difference of time, storing as offset value for stationary system, removing offset mapping to corresponding value in DAC full scale voltage during start of platform from rest to compute the braking inertia of the system.
[0040] In one embodiment, measuring inertia time for accelerating system comprising: applying a fractional value of full scale DAC voltage, reading encoder value, offset earlier inertial values from present observations, increment DAC voltage in steps of fractional power of 2 or Fibonacci ratio to DAC full scale range, read encoder values, compare the target angle position from true north, offset the inertial time and check whether further acceleration is required, store the accelerating inertial offset time for next cycle of positioning.
[0041] In one embodiment, measuring inertia time for decelerating system comprising: applying a fractional value of full scale DAC voltage, reading encoder value, decrement DAC voltage in steps of fractional power of 2 or Fibonacci ratio to DAC full scale range, read encoder values, compare the target angle position from true north, offset the inertial time and check whether further deceleration is required, store the decelerating inertial offset time for next cycle of positioning.
[0042] In one embodiment, measuring inertia time for braking system comprising: applying a fractional value of full scale DAC voltage after applying brake for the system, reading encoder and averaging over clock cycles, computing the difference of time, storing as offset value for braking system, removing offset mapping to corresponding value in DAC full scale voltage during braking of platform after deceleration, use the braking offset during positioning for very small angular movement along with stationary inertia of the system computed.
[0043] In one embodiment, the method and system further comprising converting all the electromechanical inertia of stationary and moving systems computed into equivalent encoder pulse count.
[0044] In one embodiment, the method and system further comprising inertia sensing for azimuth and elevation simultaneously while positioning platform, by rotating platform in variable speeds depending upon the angle of rotation from true north direction, by applying voltage to DAC of servo mechanism in incremental steps while accelerating and decremental steps while decelerating during calibration and positioning.
[0045] In one embodiment, the method and system further comprising predicting and computing inertial offsets using kalman filters based on the difference of encoder value between current position and intended position, compute inertial offsets for all the command modes of starting, accelerating, decelerating and braking using respective inertia times.
[0046] In one embodiment, the method and system further comprising updating previous values of all stationary, accelerating, decelerating and braking offsets with their respective current and computed inertial offsets.
[0047] In one embodiment, the method and system further comprising computing the inertial offsets with respect to full scale DAC voltage and applying correspondingly to DAC to avoid zig zag movement of conventional positioning by predicting the intended position in encoder value terms such that platform is not positioned or moved into any unintended sectors.
[0048] In one embodiment, the method steps for main control systems comprises: sending calibration command to all elements in network such that all Tracker Misleading systems trigger inertia sensing for heavy platform simultaneously and reply with inertial times for each individual platform, creating TDMA time slots for all the network elements sensed during calibration and to command and adjust dynamically timing slots when a Tracker Misleading system joins the network and leave the network, operates and maintains all the Tracker Misleading systems along with associated heavy loaded platforms in the network in a closed loop configuration using TDMA timing slots.
[0049] In one embodiment, the main control system maintains individual inertial offset for network delays associated with all Tracker Misleading systems and compensate them in command to the respective Tracker Misleading system for platform positioning and receive the reply within guard time by adjusting the TDMA time slots created against each Tracker Misleading system.
[0050] In one embodiment, the main control system and individual Tracker Misleading systems remain in closed feedback loop such that Tracker Misleading systems responds only during time slots when main control systems triggers individual Tracker Misleading systems and individual Tracker Misleading systems reply with a corresponding reply in a network; while performing inertia sensing of respective heavy platforms simultaneously while positioning azimuth and elevation platform.
[0051] Figure 1 shows an overall system block diagram of Network of Tracker Misleading System (100) according to an exemplary implementation of the present invention.
[0052] The figure shows an overall system (100) block diagram of network of tracker misleading system. The overall block diagram of the whole system where the remote tracker misleading system (130) is connected to heavy platform (140) and RTMS (130) and Main Control System (110) are connected in a network (120). The present invention relates to a technique of sensing inertia of various Tracker Misleading systems on board mission critical equipment, wherein individual TMSs are located at different physical locations whose individual servo systems are being controlled locally and all TMS are remotely monitored from a main control system wherein all the elements are networked. The physical link can be as far as 1 to 2 Kms which are primarily connected using fiber optic cables. The remote TMS will be a chaff dispenser based on the command received from the main or master control system. The chaff will be dispensed to varying distances depending upon the control and command from main control system, like Short-range, Mid-range and Long Range. An appropriate firing electrical circuitry gets energized based on control from main control system. These commands are sent with a suitable protocol from main control system to remote TMS for necessary action. The platform of TMS will be carrying heavy load of several 100s of kilo grams of metal body. The whole network of TMS comprises electronic circuit with op-amp, DAC, MOSFETs etc., and electrical circuits with servo mechanism and actual heavy platform with chaff dispenser which offers lot of inertia in rotating the platform.
[0053] The present invention method creates TDMA structure superimposed over the standard CSMA/CA 802.11 that does the inertia sensing of all TMS in the network periodically, continuously measures the static and dynamic inertia of the whole electro-mechanical systems, keeps intact the logical loop between main or master system and all remote TMSs, dynamically creates the timing slots based on new TMS joining the network on an adhoc basis, achieves simultaneous and accurate platform positioning in azimuth and elevation directions in all individual TMS even with mechanical manufacturing misalignments in servo systems and chaff dispenser platforms.
[0054] The concept of inertia sensing disclosed in the present invention estimates the static and dynamic inertia of stationary as well as moving platforms, predicts the platform position in advance by offsetting the inertial delays, effectively handles all the delays associated with intermittent electrical circuitry and mechanical systems from main control system till chaff dispenser. The present invention pertains to one such scenario, wherein multiple TMSs located physically at various places are networked and controlled from a master or main control system. The master control system provides the command to individual TMS based on incoming threat as read by other sensors on board the mission critical system like Radar, Electro Optic systems etc.
[0055] The present invention relates to a method in which, a main or master control system communicates with all TMSs to provide commands for platform positioning and maintains a closed loop with all TMSs. This method overcomes all the network delays, inertia delays of electric circuitry delays, electronic servo mechanism delays and mechanical mounting and alignment irregularities to achieve sub degree accuracies for platforms loaded with several 100s of kgs of weight.
[0056] In the present invention method and system, the main control system is located in a central place, which controls all the TMS which are located at different locations and directions, connected by a fiber optic cable with suitable networking protocol. The present invention system and method ensures a smooth positioning based on inertia sensing estimates of the platforms.
[0057] The present method, proposes, with respect to TMS to estimate the inertial response time, based on the reaction time for homing position of the platform during calibration after power up, calculate offset or residual error voltage for servo drive to provide platform positioning command, maintain closed local loop within each TMS between control unit and servo system using ADC and DAC, keep sending the platform positioning periodically to the main control system along with health status of the platform, depending upon the time slots created by main control system to the respective TMS.
[0058] The main control system initiates inertia sensing for all the TMS, converts the sensed time into equivalent electrical pulses and store them as offset for further commands, understand and discover number of TMS operating in the network at a time, create and maintain the time slots for each and individual TMS as long as they communicate with agreed protocol within the time period estimate, maintain the closed logical loop with all remote systems by periodical polling, provide the command when required in the allotted time slot to the TMS, thus achieves the accurate platform positioning within +/- 0.1 degrees and overcomes the alignment and mounting errors or aberrations of all heavy platforms associated with each TMS.
[0059] The present invention method and system performs inertia sensing for electromechanical system of heavy loaded platform when operated in a network and creates TDMA structure for main control systems and remote tracker misleading systems that fixes the time delay of platform positioning and overcomes accuracies errors due to mounting and misalignment errors.
[0060] Figure 2 shows a block diagram of remote tracker misleading system (200) according to an exemplary implementation of the present invention.
[0061] The figure shows a block diagram of remote tracker misleading system (200). The individual remote TMSs (210) which are attached to servo systems (220), receives the commands from main system and does accurate platform positioning to release chaffs via chaff dispensing (230) in time synchronized manner.
[0062] During initial power up, calibration can be done for determining the home position of platform, and if pre-defined, homing position of platform can always be constant with respect true north. If the platform is at a different location, calibration voltage can be applied to servo motor to get the platform to required home position. The process/method steps inside the control element can be implemented such that the rotation angle can be given in numbers of steps so that platform can pick up the speed depending upon the distance of the destination. Even when platform is reaching the intended destination, application of servo voltage can be in gradual manner such that jerks are avoided during halting and breaking time which is easily achieved in a closed loop configuration.
[0063] During the process of calibration, the control element process steps has an intelligence to observe the round trip response time of the platform, which includes the response times of servo mechanism, rotating elements, encoder which can be absolute or incremental, converts whole response time into its equivalent electrical pulse count, store it such that it can be averaged over time when the platform is moved at multiple time at multiple instances.
[0064] Different platforms which are manufactured in different conditions and mounted, may offer different time delays. The respective control elements of individual Tracker Misleading systems capture the inertia delays and response times by doing inertia sensing, encompasses the mechanical alignment problems, communicate the sensing delays to master control system in a periodic manner as health status.
[0065] The master/main control system initiates the inertia sensing during power on calibration, determines the number of TMS, converts the round trip delay times of each and every individual TMS, convert the inertial time response into equivalent electrical pulses associated with them, creates the TDMA time slot for all the TMS, assigns a protocol structure according the to the physical link used. The present invention is explained using example of Ethernet link with UDP protocol as reference. Though it is explained with Ethernet link the same concept can be extended to any other protocol structure depending upon the link like RS232 protocol for uart link, I2c or even SPI links given that these electrical links are converted to optical domain and carried over kms of range using cables.
[0066] All the TMS available in the network at an instance of time will be responding only during the slotted time, sends the inertial delays, health status and platform position information in a master slave mode, solving the communication conflicts and collisions across TMS and master control system.
[0067] Figure 3 shows a block diagram of inertial sensing circuit (300) for Remote Tracker Misleading System for sensing the heavy loaded platform according to an exemplary implementation of the present invention.
[0068] The figure shows a block diagram of inertial sensing circuit (300) for Remote Tracker Misleading System for sensing the heavy loaded platform. The inertial sensing circuit (300) of each TMS comprising FPGA/CPU (310), clock (320), DAC (330), Op-Amp (340), MOSFETS and electrical energizing circuitry (350) for servo drive (360) mechanism in transmit side, and encoder (380) and ADC (390) in receiver side and communicate the sensing delays to main/master control system in a periodic interval. The system consists of controlling element like FPGA/CPU (310) for inertia sensing of whole electromechanical system, and appropriate DAC (330) to provide corresponding code to generate required voltage for the servo motor mechanism to move the platform. An ADC (390) connected in back to back to DAC (330) in piggyback mode to monitor the voltage applied to servo system. These elements will be operated in a closed loop without missing data for even one clock cycle. The encoder values are read to know the exact platform position. For incremental encoder, exact position may have to be calculated with respect to homing reference and for absolute encoder exact positional value may directly be read by the FPGA/CPU (310).
[0069] The Field Programmable Gate Array is used as main computing element in each Remote TMS, which can be realizing the loop control systems in real time with minimal delays. The FPGA and Digital to Analog Converter is used to generate the required voltage for servo system, which in turn energizes the motor system for moving the heavy platform. The diagrams also indicate the usage of operational amplifiers for amplification of signals after generation from DAC. All these elements delay the propagation of control information to heavy platform which contributes to the inertia of the system. The encoder provides the information about platform current position which is read through suitable level converters into FPGA/CPU, which maintains the inertia sensing information and timing offsets for the entire platform.
[0070] The ADC and DAC and their maximum sampling frequencies chosen for this electromechanical inertia measurement of the TMS are much higher than the response times of the servo mechanism and electric motors attached to move the heavy platform (370). Also, the clock (320) used to trigger ADC (390) and DAC (330) are fed from the same source. The bit resolution chosen for ADC and DAC are the same to measure DAC voltage applied to servo mechanism and ADC values read from encoder are maintained to be with the same scale. The same clock is fed to FPGA to operate the design inside FPGA for the whole design logic to achieve better synchronization among all the elements and maintains accurate inertia offset values.
[0071] Intelligence related to entire remote TMS is calibrated to do following tasks: Sensing and Measuring Electro-Mechanical Inertia of the system:
Upon power on reset or calibration command, the encoder reading is read or polled for more of numbers clocks and averaged to reduce noise readings and spike values;
Small percentage of full scale value is applied to DAC to energize the servo mechanism and start polling the encoder (380) through ADC along with simultaneous start of a counter value in a register;
Keep polling the ADC values for change of value registered in the encoder;
Register the difference of data value as static inertia of the system and maintain as the static inertia offset;
Compute the difference of encoder value from true north, scale up the DAC voltage in steps with static inertia offset, and then start reading the encoder value for the steps of accelerating, store the difference as respective dynamic inertia of the platform while accelerating;
Keep track of the encoder value and estimate the time of braking in terms of encoder count value for home position in advance by using kalman filter;
Within the dynamic inertia offset encoder value window, start applying the DAC voltage in reducing steps and read the encoder values;
Value of the counter differences computed are registered as decelerating inertia offset and stored in FPGA;
While applying the brake for the servo motor, release the DAC driver to high impedance and read encoder value for home position, difference count value before applying brake and encoder value read to standstill at the home position will be registered as braking inertia offset;
When platform position command is received from Main control system, again all the stationary inertia, dynamic accelerating inertia, dynamic decelerating inertia are calculated which are offset during positioning command and the corresponding offset values are used for estimation of future platform position.
[0072] Figure 4 shows flowchart of steps for closed loop control in Main Control System according to an exemplary implementation of the present invention.
[0073] The figure shows flowchart of steps for closed loop control in Main Control System. The flowchart comprises few steps as the main control system does power on checks in routine and starts the calibration process, checks for TMS available in the network and initiates inertia sensing for all TMS, calculate electrical equivalent of network inertia of each platform and offset value for synchronized platform positioning, creates TDMA time slots for all available TMS and go to idle state, wait for the external input from the sensors computing device and if the trigger is to place platform in a required direction, provide command to respective TMS for positioning as per TDMA time slot created and if the trigger is to dispense chaff in already positioned platform, provide command to particular TMS, remain in inertia sensing state to keep observing or polling for all TMS in a time bound manner.
[0074] Any conventional platform positioning system rotates the platform based on the initial difference from intended angle to positioned angle, checks for the error from intended angle, provides a reverse or forward command to move again the platform in a zig and zag manner and achieves the positioning accuracy in number of steps whereas, the present method of two continuous loops with inertia sensing, primarily within TMS and heavy platforms at remote locations, along with main control system and remote TMS with network sensing, can effectively achieve platform accuracies as good as +/- 0.1 degrees in both azimuth and elevation directions simultaneously overcoming all the mechanical mounting and manufacturing anomalies along with huge network delays associated with long distance cables. The technique described can be super imposed over communication link using CAN, 1553 bus architectures.
[0075] Figure 5 shows a flowchart of steps for closed loop control in Remote Tracker Misleading System according to an exemplary implementation of the present invention.
[0076] The figure shows a flowchart of steps for closed loop control in Remote Tracker Misleading System. The flowchart comprises few steps as: Initially, remote TMS does power on checks in routine and starts the calibration process. As a part of calibration, the method and system does homing position with respect to true north of heavy loaded platform by giving servo voltage control to digital to analog converter, does continuous inertia sensing of the platform using analog to digital converter till the process of homing position is complete, calculate electrical equivalent of mechanical inertia of the platform and offset value for accurate platform positioning irrespective of weight, compute overall static inertia, accelerating inertia, decelerating inertia and braking inertia of the electro-mechanical system, estimate the encoder count equivalent of the all the observed inertia, wait in an idle state till input trigger comes from main control system for platform positioning or periodical health check and inertial sense data of platform and if trigger is for platform positioning, go to platform positioning state and do inertia sensing even during platform positioning, go to inertia sensing state and feed the sensed data back to average offset values, go to idle state to wait for trigger again and if the trigger is for health state and inertial data to main control state, go to reply state, send reply to main control system and revert back to idle state, keep waiting in the idle state for further trigger from main control system thus maintaining closed loop in itself as well with main control system
[0077] Figure 6 shows a method for platform positioning in a network of tracker misleading systems (TMS) according to an exemplary implementation of the present invention.
[0078] The figure shows a method for platform positioning in a network of tracker misleading systems (TMS). In one embodiment, the method (600) for platform positioning in a network of tracker misleading systems (TMS), the method comprising: calibrating a plurality of electro-mechanical systems of TMS coupled in the network for determining home position of each platform in the network of TMS’s by a main control system (610), initiating a static and dynamic inertial sensing of the plurality of electro-mechanical systems in the network of TMS’s and receiving the inertial sensing times by each platform of the network of TMS’s (620), calculating an electrical equivalent of network inertia of each platform of the network of TMS’s and predicting an offset value from the received static and dynamic inertia times based on the difference of value between a current position and an intended position for synchronized platform positioning (630), creating a TDMA time slot structure for all the available TMS in the network during calibration and maintaining a closed loop using TDMA timing slots (640) and providing a command to respective TMS by the main control system for platform positioning as per TDMA time slot created to place the platform in a required direction (650).
[0079] The method further comprising receiving an external trigger by the main control system for positioning respective platform of the TMS’s in a respective direction from an external sensor computing unit. The method further comprising dynamically adjusting the TDMA time slots for all the TMS’s joining or leaving the network. The method further comprising maintaining an individual inertial sensing offset for all delays associated with all the Tracker Misleading systems of the network and compensating the delay in the command to the respective Tracker Misleading system’s for platform positioning and receiving the response within a guard time by adjusting the TDMA time slots created for each Tracker Misleading system’s.
[0080] The main control system and the individual TMS’s remain in closed feedback loop such that each Tracker Misleading systems (TMS) responds only during time slots when main control systems commands the individual Tracker Misleading systems.
[0081] The method for platform positioning of each TMS comprises: calibrating a home position of the platform with respect to true north by each TMS based on the command from the main control system, measuring a static and dynamic inertial sensing of the plurality of electro-mechanical systems of the platform till the calibration process of homing position is complete, by an inertial sensing circuit of each TMS, calculating an electrical equivalent of inertia times of the platform and offset value for platform positioning by the inertial sensing circuit of each TMS, estimating and predicting an encoder count based on the calculated electrical equivalent and the intended electrical equivalent for stationary, accelerating, decelerating, and braking systems by the inertial sensing circuit and communicating the same to the main control system and positioning the platform by respective TMS in a required direction, when the command is received from the main control system for positioning the platform.
[0082] The method further comprising measuring the static and dynamic inertial sensing of the plurality of electro-mechanical systems of TMS comprises measuring inertial time offset of the electro-mechanical system when the system is stationary, accelerating, decelerating, braking, etc. The method further comprising capturing inertia times of plurality of electro-mechanical systems of TMS by the inertial sensing circuit of each Tracker Misleading system, converting the sensed/captured inertial times into equivalent electrical pulses and communicate the captured delays to main/master control system in a periodic interval. The method further comprising sensing a mechanical alignment by the inertial sensing circuit of each Tracker Misleading system and communicate the sensing delays to main/master control system in a periodic interval as health status. The method further comprising sensing a electrical circuitry comprising DAC, Op-Amp MOSFETS and electrical energizing circuitry for servo drive mechanism in transmit side, and encoder and ADC in receiver side by the inertial sensing circuit of each Tracker Misleading system and communicate the sensing delays to main/master control system in a periodic interval. The method further comprising inertia sensing for azimuth and elevation simultaneously while positioning the platform. The calculated offset value is updated for all commands for platform positioning.
[0083] The method further comprising measuring the static and dynamic inertial sensing comprising: generating the voltage by FPGA and applying a required voltage for a servo system of the TMS via DAC, amplifying the generated voltage by an operational amplifier and providing the amplified voltage to the servo system for moving the platform of the TMS, capturing an electromechanical inertia of the TMS and converting all the captured electromechanical inertia times of the TMS into equivalent encoder pulse count by an encoder with respect to the full scale range of DAC (Digital to Analog Converter) chosen, sampling the encoder pulse count with a very high sampling clock, calculating and storing the offset difference of clock pulse counts and providing the encoded pulse count of the TMS to a FPGA/CPU for mapping offset to corresponding value DAC full scale voltage, to maintain the inertia sensing information and offsets for the platform of the TMS.
[0084] In another embodiment, the present invention relates to a system for platform positioning in a network of tracker misleading systems (TMS), the system comprising a processing unit configured to perform the steps: calibrating a plurality of electro-mechanical systems of TMS coupled in the network for determining home position of each platform in the network of TMS’s by a main control system, initiating a static and dynamic inertial sensing of the plurality of electro-mechanical systems in the network of TMS’s and receiving the inertial sensing times by each platform of the network of TMS’s, calculating an electrical equivalent of network inertia of each platform of the network of TMS’s and predicting an offset value from the received static and dynamic inertia times based on the difference of value between a current position and an intended position for synchronized platform positioning, creating a TDMA time slot structure for all the available TMS in the network during calibration and maintaining a closed loop using TDMA timing slots and providing a command to respective TMS by the main control system for platform positioning as per TDMA time slot created to place the platform in a required direction. In the present invention, the processing unit may be a FPGA, microcontroller, microprocessor, Central Processing Unit (CPU) devices, computing devices, digital signal processors or like devices/units.
[0085] In another embodiment, the present invention relates to a system for platform positioning of each TMS, the system comprising a processing unit configured to perform the steps: calibrating a home position of the platform with respect to true north by each TMS based on the command from the main control system, measuring a static and dynamic inertial sensing of the plurality of electro-mechanical systems of the platform till the calibration process of homing position is complete, by an inertial sensing circuit of each TMS, measuring a static and dynamic inertial sensing of the plurality of electro-mechanical systems of the platform till the calibration process of homing position is complete, by an inertial sensing circuit of each TMS, calculating an electrical equivalent of inertia time of the platform and offset value for platform positioning by the inertial sensing circuit of each TMS, estimating and predicting an encoder count based on the calculated electrical equivalent and the intended electrical equivalent for stationary, accelerating, decelerating, and braking systems by the inertial sensing circuit and communicating the same to the main control system and positioning the platform by respective TMS in a required direction, when the command is received from the main control system for positioning the platform.
[0086] Figures are merely representational and are not drawn to scale. Certain portions thereof may be exaggerated, while others may be minimized. Figures illustrate various embodiments of the invention that can be understood and appropriately carried out by those of ordinary skill in the art.
[0087] In the foregoing detailed description of embodiments of the invention, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments of the invention require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby incorporated into the detailed description of embodiments of the invention, with each claim standing on its own as a separate embodiment.
[0088] It is understood that the above description is intended to be illustrative, and not restrictive. It is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined in the appended claims. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein,” respectively.