DESC:TECHNICAL FIELD
The present invention generally relates to signal processing, and more particularly, to identifying and analyzing signals for identifying emitters.

BACKGROUND
The electromagnetic environment is becoming more and more dense and complex. An emitter is an instance of a radar type and a considered environment may comprise several emitters of a same type that may be active in a theatre of operation. A single type of radar can also operate under several different modes to perform various functions. However, the task of isolating a particular signal from a specific emitter can be difficult to accomplish, since the parameter boundaries between different signals may overlap, and since factors such as measurement error can cause the measured characteristics of the signal to become inexact or fuzzy.

Electronic Support Measures (ESM) is a division of electronic warfare (EW) that searches for, intercepts, locates, and immediately identifies sources of enemy electromagnetic radiations for the purposes of immediate threat recognition and for tactical employment of military forces or asset. ESM is used for intercepting, where intercepting primarily comprises detection, frequency estimation and direction finding, identifying, analysing, and locating sources of hostile radiations. ESM is used for 'tactical' purposes that require immediate actions as contrasted with similar functions which are performed for intelligence gathering, such as Signal Intelligence (SIGINT), which has Electronic Intelligence (ELINT), Communications Intelligence (COMINT) and Radiation Intelligence (RINT) as its constituent parts.

An electronic intelligence (ELINT) system de-interleaves radar signals, that is, the ELINT groups the signals according to source of emission, that is, emitters. The ELINT discriminates between the emitters. Large number of emitters increases complexity of the de-interleaving process and makes the de-interleaving process a challenging task.

CA2000674C mentions an associative hierarchical de-interleaver wherein sequential signal pulses from unknown sources are de interleaved by clustering similar pulses into groups. The groups are used to form hypothetical pulse train models. If the hypotheticals are confirmed, they are used to de interleave corresponding signal pulses. Unconfirmed hypothetical models are removed from a database. The associative hierarchical de-interleaver has application in the sorting and identifying of radar signal sources in an electronic surveillance system.

However, there are no separate processing methods for known and unknown radars, hence it becomes difficult to handle multiple emitters simultaneously whose parameters are very close to one another and radars having agility in all its parameters.

Therefore, there is a need for a system and a method for handling multiple emitters simultaneously whose parameters are close to one another and radars having agility in all its parameters and the emitters that are unknown.

SUMMARY
The main objective of the present invention is to identify multiple emitters, that are both known and unknown, whose parameters are close to one another and comprise agility in the parameters.

A method for implementing adaptive filters in a de-interleaving process for known and unknown emitters is disclosed. An adaptive filter system (AFS) executes steps of the method for implementing adaptive filters in a de-interleaving process for known and unknown emitters. An emitter parameter library comprising complete information of plurality of emitter pulse parameters of a plurality of known emitters is provided. The emitter parameter library comprises information about the parameters corresponding to known emitters. The plurality of parameters are frequency, pulse width, pulse repetition interval, direction of arrival, amplitude, and scan period. An Electronic Intelligence (ELINT) receiver receives passively intercepted radar signals comprising a mixture of electromagnetic pulses transmitted from one or more radar sources. The ELINT receiver determines a plurality of parameters of the received radar signals. The ELINT receiver generates pulse descriptive words (PDWs).

The PDWs are validated for considering pulses that are not reflections. The validation of the pulse descriptive word aids in accurate track formation by rejecting reflections causing low pulse width, low pulse repetition interval generation due to pulse breakage and interceptions in multiple directions with lower strength. The ELINT receiver sorts and groups the PDWs based on the emitter pulse parameters corresponding to individual emitters that are active in a considered environment. The AFS receives the pulse descriptive word that is further provided for known radar processing. The PDWs are provided to one or more first set of cells comprising one or more adaptive filters for processing. The AFS adjusts limits of the one or more adaptive filters based on values of previous intercepts stored in the emitter parameter library. Each cell of the first set of cells allow multiple modes of a radar with multiple frequencies, pulse width & pulse repetition interval to be processed. The AFS determines if the provided pulse descriptive word belongs to a known radar based on the one or more pulse parameters. The pulse parameters for determining if the provided pulse descriptive word belongs to a known radar are frequency, pulse width, direction of arrival, time of arrival bits of the pulse descriptive word and pulse repetition interval value. A cell match signal is generated upon determining that the provided pulse descriptive word belongs to a known radar. A track comprising statistical pulse descriptive word parameters and pulse repetition interval derived from the sequence of grouped pulse descriptive word is displayed. The number of cells correspond to the number of radars that can be processed and the availability of number of cells for processing are programmable.

Upon determining that the provided pulse descriptive word belongs to an unknown radar, the pulse descriptive word is provided to a second set of cells comprising one or more adaptive filters, for extracting emitter pulse parameters of the emitter that is the source of the radar signal. Fixed tolerance values are assigned for each of the adaptive filters in the second set of cells for determining higher and lower limits of the unidentified emitter. A plurality of parameters of the unknown radar are extracted by using the second set of the adaptive filters. The extracted parameters from the radar signals of the unknown radar are stored in the emitter parameter library. A track comprising statistical pulse descriptive word parameters and pulse repetition interval (PRI) derived from the sequence of grouped pulse descriptive word is displayed.

BRIEF DESCRIPTION OF THE DRAWINGS
The detailed description is described with reference to the accompanying figures.

Figures 1A-1B illustrates a method for implementing adaptive filters in a de-interleaving process for known and unknown emitters.
Figure 2 exemplarily illustrates a functional block diagram of a method of de-interleaving, according to an exemplary implementation of the present disclosure.
Figure 3 exemplarily illustrates a method of performing a known radar de-interleaving process, according to an exemplary implementation of the present disclosure.
Figure 4 exemplarily illustrates a method of performing an unknown radar de-interleaving process, according to an exemplary implementation of the present disclosure.
Figure 5 illustrates an adaptive filter system for identifying emitters.

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 computer or processor, whether or not such computer or processor is explicitly shown.

DETAILED DESCRIPTION
The various embodiments of the present invention describe about adaptive filter system, that is, adaptive filter implementation, and methods thereof. 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 invention and are meant to avoid obscuring of the present invention.In the following description, for purpose of explanation, specific details are set forth in order to provide an understanding of the present invention. 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 invention, some of which are described below, may be incorporated into a number of systems.

It should be noted that the description merely illustrates the principles of the present invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present invention. Furthermore, all examples recited herein are principally intended expressly to be only for explanatory purposes to help the reader in understanding the principles of the invention and the concepts contributed by the inventor to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass equivalents thereof.

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.

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. It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. 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 is intended to provide.

Figures 1A-1B illustrate a method for implementing adaptive filters in a de-interleaving process for known and unknown emitters. An adaptive filter system (AFS) executes steps of the method for implementing adaptive filters in a de-interleaving process for known and unknown emitters. The AFS provides an emitter parameter library comprising complete information of plurality of emitter pulse parameters of a plurality of known emitters. The emitter parameter library comprises information about the parameters corresponding to known emitters. The plurality of parameters are frequency, pulse width, pulse repetition interval, direction of arrival, amplitude, and scan period. An Electronic Intelligence (ELINT) receiver receives passively intercepted radar signals comprising a mixture of electromagnetic pulses transmitted from one or more radar sources. The ELINT receiver determines a plurality of parameters of the received radar signals. The ELINT receiver generates pulse descriptive words (PDWs).

The PDWs are validated for considering pulses that are not reflections. The validation of the pulse descriptive word aids in accurate track formation by rejecting reflections causing low pulse width, low pulse repetition interval generation due to pulse breakage and interceptions in multiple directions with lower strength. The ELINT receiver sorts and groups the PDWs based on the emitter pulse parameters corresponding to individual emitters that are active in a considered environment. The AFS receives the pulse descriptive word that is further provided for known radar processing. The PDWs are provided to one or more first set of cells comprising one or more adaptive filters for processing. The AFS adjusts limits of the one or more adaptive filters based on values of previous intercepts stored in the emitter parameter library. Each cell of the first set of cells allow multiple modes of a radar with multiple frequencies, pulse width & pulse repetition interval to be processed. The AFS determines if the provided pulse descriptive word belongs to a known radar based on the one or more pulse parameters. The pulse parameters for determining if the provided pulse descriptive word belongs to a known radar are frequency, pulse width, direction of arrival, time of arrival bits of the pulse descriptive word and pulse repetition interval value. A cell match signal is generated upon determining that the provided pulse descriptive word belongs to a known radar. A track comprising statistical pulse descriptive word parameters and pulse repetition interval derived from the sequence of grouped pulse descriptive word is displayed. The number of cells correspond to the number of radars that can be processed and the availability of number of cells for processing are programmable.

Upon determining that the provided pulse descriptive word belongs to an unknown radar, the pulse descriptive word is provided to a second set of cells comprising one or more adaptive filters, for extracting emitter pulse parameters of the emitter that is the source of the radar signal. Fixed tolerance values are assigned for each of the adaptive filters in the second set of cells for determining higher and lower limits of the unidentified emitter. A plurality of parameters of the unknown radar are extracted by using the second set of the adaptive filters. The extracted parameters from the radar signals of the unknown radar are stored in the emitter parameter library. A track comprising statistical pulse descriptive word parameters and pulse repetition interval (PRI) derived from the sequence of grouped pulse descriptive word is displayed.

The AFS allows defining limits for various emitter parameters such as frequency, pulse width (PW), pulse repetition interval (PRI), direction of arrival (DOA), amplitude, scan period. There is a meager possibility of overlap of limits of the parameters, thereby leading to separation of closely spaced emitters. The method also provides flexibility of having adaptive limits for DOA, Amplitude, pulse width and PRI values for resolving issues related to reflections that cause low pulse width, low PRI generation due to pulse breakage and interceptions in multiple directions with lower strength. Therefore, valid pulses are processed, and accurate track parameter is formed. The method also allows programming limits at multiple levels of limits for each parameter in each of the adaptive filter, thereby providing scope for processing different modes of emitter as a single source. The method also allows an unknown emitter mode of operation if the environment has unknown emitters.

Figure 2 exemplarily illustrates a functional block diagram of a method of de-interleaving electromagnetic signals such as radar signals detected by a receiver. The radar signals are passively intercepted by a receiver portion of an electronic support measure (ESM) system. The ESM system comprises an Electronic Intelligence (ELINT) receiver that receives radar signals, and groups pulses based on emitters and identifies of corresponding radar types. The intercepted radar signals are a mixture of electromagnetic pulses transmitted from multiple sources, such as multiple emitters. Simultaneous illumination by multiple emitters causes overlap and interleaving of the received pulses. Upon detection of a radar pulse, the ELINT receiver measures parameters such as pulse amplitude (PA), pulse width (PW), radio frequency of the carrier wave (RF) and time of arrival (TOA) and a direction-finding receiver also measures the direction of arrival (DOA). The ELINT receiver is a part of an electronic warfare (EW) receiver. Upon measuring the parameter values for pulses by the ELINT receiver, the pulses are digitized and assembled into a data structure called a pulse descriptor word (PDW). A generic PDW validation is performed and the valid PDW is used for further processing.

The method of de-interleaving is a process of separation of radar signals for determining whether a newly intercepted radar pulse belongs to one of already detected emitters or to a new emitter. Streams of successive pulse descriptor words (PDWs) are fed as an input to a pulse processor de-interleaving module. The PDWs are sorted in real-time for grouping primary pulse parameters belonging to each of individual emitters that are currently active in a considered environment.

The input pulse descriptor word (PDW) from the Electronic Intelligence (ELINT) receiver is fed directly to the pulse processor de-interleaving module. Aknown radar processing module of the pulse processor de-interleaving module comprises the adaptive filters and the PDWs are fed to the first set of cells. The first set of cells compriseone or more adaptive filters. An emitter processor provides limits to the adaptive filters based on an emitter parameter library (EPL). The EPL comprises details about previous intercepts. A track is associated to each group of pulses. The track comprises statistical PDW parameters, along with other parameters that are derived from the sequence of grouped PDWs, such as pulse repetition interval (PRI). The PDW parameters along with other parameters is sent to the emitter processor for identification of changing PRIs like agile PRI, staggered PRI and Jitter PRIs.

The pulse repetition interval (PRI) value of each of the cells is determined by time of arrival bits of the PDW. The PRI values are required for identifying signals of many radar systems, therefore the PRI values are required for cell match signal generation. If the input PDW is not processed in a known radar processing module, that is known de-interleaver block, then the input PDW is provided to an unknown radar processing module, that is unknown de-interleaver block automatically. The limits for each match cell in the unknown de-interleaver block are determined based on one or more tolerance values by the emitter processor. Upon processing a newly intercepted emitter successfully and obtaining the radar data, the intercept is updated in the emitter parameter library (EPL) and the radar data is further sent to display for formation of the tracks.

Figure 3 exemplarily illustrates a method of performing a known radar de-interleaving process. The input pulse descriptor word (PDW) from the ELINT receiver is fed directly to the adaptive filters, that are cells, of the known radar processing. The emitter processor provides the limits to the adaptive filters of the first set of cells based on the emitter parameter library (EPL) that comprises details about the previous intercepts. If the intercepted pulse belongs to a known radar then the known radar cell block generates a frequency, pulse width, pulse repetition interval, and a cell match signal. Each cell can accept entries related to multiple frequencies and multiple pulse width limits, thereby supporting processing of multiple modes of the radar in a single cell.

The processing of multiple modes of the radar in a single cell resolves problems related to multiple track formation for single emitter when radar operates in different modes. A pulse repetition interval (PRI) value of each cell is determined by time of arrival bits of the PDW. The PRI values are required for identifying signals of multiple radar systems, therefore the PRI values are required for generation of a cell match signal. For example, the known radar de-interleaving process, exemplarily illustrated in Figure 2, processes K radars simultaneously, and the value of K and each of the radar parameters are programmable.

Figure 4 exemplarily illustrates a method of performing an unknown radar de-interleaving process. If the input pulse descriptor word (PDW) is not processed in the known radar processing module then the input PDW is provided to the unknown radar processing module automatically. The input PDW provided to the unknown radar processing module belongs to a newly intercepted emitter. Therefore, no prior information about the emission from the emitter, or the previous intercepts are present in the EPL. The input PDW is processed based on one or more fixed tolerance values that determine higher limits and lower limits for each cell. The emitter processor provides limits for each cell. Upon processing a newly intercepted emitter successfully and obtaining the radar data, the intercept is updated in the EPL. The detection of emitters involve usage of multiple parameters for accurate results rather than individual parameters considered separately. The radar data is further provided to a display unit for formation of the tracks.

Figure 5 illustrates the adaptive filter system 500 for unknown and known emitters processing. The adaptive filter system 500 comprises a pulse processor de-interleaving module 502, the emitter processor 505, and the emitter parameter library 506. The pulse processor de-interleaving module comprises the known radar processing module 503 and the unknown radar processing module 504.

The input pulse descriptor word (PDW) from the Electronic Intelligence (ELINT) receiver 501 is fed directly to the pulse processor de-interleaving module 502. The known radar processing module 503 of the pulse processor de-interleaving module 502 comprises the adaptive filters and the PDWs are fed to the first set of cells. The first set of cells comprise one or more adaptive filters. If the known radar processing module 503 identifies the emitter, then the known radar processing module 503 generates a cell match signal, as disclosed in the detailed descriptions of Figure 2 and 3. If the known radar processing module 503 is unable to identify the emitter, then the PDWs are provided to the unknown radar processing module 504. The unknown radar processing module 504 comprises one or more cells with higher and lower limits. The unknown radar processing module 504 processes newly intercepted emitters and stores the details about the newly intercepted emitter in the EPL 506, as disclosed in the detailed description of Figure 2 and 3.

The emitter processor 505 supports implementation of de-interleaving of signals of known emitters from the data, implementation of de-interleaving of signals of unknown emitters from the data, implementation of integrated de-interleaving signals for known and unknown emitters, updating the existing library of emitters, that is the emitter parameter library (EPL), with newly intercepted emitter, and providing limits to the cells in the known radar block and the unknown radar block. In an embodiment, a plurality of processors are used, where one processor of the plurality of processor supports implementation of de-interleaving of signals of known emitters from the data, implementation of de-interleaving of signals of unknown emitters from the data, implementation of integrated de-interleaving signals for known and unknown emitters, updating the existing library of emitters, that is the EPL 506, with newly intercepted emitter. Another processor of the plurality of processors provides limits to the cells in the known radar block and the unknown radar block.

The EPL 506 comprises details about previous intercepts, the limits for the adaptive filters, that are the first set of cells. The EPL 506 further comprises the fixed tolerances for the second set of cells. In an embodiment, the second set of cells are filters that do not have the provision adjusting the limits.

The adaptive filter system 500 resolves issues related to merging of emitter data at de-interleaving stage when pulse parameters of the emitters are close to one another in a dense environment and also resolves problems related to spurious tracks. The adaptive filter system 500 resolves also resolves problems related to PRI extraction due to reflections in the environment that generate multiple PRIs that leads to failure in track formation. The adaptive filter system 500 also resolves problems related to an emitter that comprises wide range agility in parameters and different modes of operation, and where multiple tracks are generated for a single emitter.In an embodiment, the adaptive filter system is implemented in a non-transitory computer readable storage media.

It will be readily apparent in different embodiments that the various methods, and system disclosed herein are implemented on non-transitory computer readable storage media appropriately programmed for computing devices. The non-transitory computer readable storage media participate in providing data, for example, instructions that are read by a computer, a processor or a similar device. In different embodiments, the “non-transitory computer readable storage media” also refer to a single medium or multiple media, for example, a centralized database, a distributed database, and/or associated caches and servers that store one or more sets of instructions that are read by a computer, a processor or a similar device. The “non-transitory computer readable storage media” also refer to any medium capable of storing or encoding a set of instructions for execution by a computer, a processor or a similar device and that causes a computer, a processor or a similar device to perform any one or more of the methods disclosed herein. Common forms of the non-transitory computer readable storage media comprise, for example, a floppy disk, a flexible disk, a hard disk, magnetic tape, a laser disc, a Blu-ray Disc® of the Blu-ray Disc Association, any magnetic medium, a compact disc-read only memory (CD-ROM), a digital versatile disc (DVD), any optical medium, a flash memory card, punch cards, paper tape, any other physical medium with patterns of holes, a random access memory (RAM), a programmable read only memory (PROM), an erasable programmable read only memory (EPROM), an electrically erasable programmable read only memory (EEPROM), a flash memory, any other memory chip or cartridge, or any other medium from which a computer can read. The processor is communicatively coupled to the non-transitory computer readable storage medium. A “processor” means any one or more microprocessors, Central Processing Unit CPU devices, computing devices, microcontrollers, digital signal processors or like devices.

In an embodiment, the EPL is a database. Where databases are described such as local database central database, it will be understood by one of ordinary skill in the art that (i) alternative database structures to those described may be employed, and (ii) other memory structures besides databases may be employed. Any illustrations or descriptions of any sample databases disclosed herein are illustrative arrangements for stored representations of information. In an embodiment, any number of other arrangements are employed besides those suggested by tables illustrated in the drawings or elsewhere. Similarly, any illustrated entries of the databases represent exemplary information only; one of ordinary skill in the art will understand that the number and content of the entries can be different from those disclosed herein. In another embodiment, despite any depiction of the databases as tables, other formats including relational databases, object-based models, and/or distributed databases are used to store and manipulate the data types disclosed herein. Object methods or behaviours of a database can be used to implement various processes such as those disclosed herein. In another embodiment, the databases are, in a known manner, stored locally or remotely from a device that accesses data in such a database. In embodiments where there are multiple databases, the databases are integrated to communicate with each other for enabling simultaneous updates of data linked across the databases, when there are any updates to the data in one of the databases.

FIGS. 1A-5 are merely representational and are not drawn to scale. Certain portions thereof may be exaggerated, while others may be minimized. FIGS. 1A-5 illustrate various embodiments of the invention that can be understood and appropriately carried out by those of ordinary skill in the art.

The foregoing and other features of embodiments will become more apparent from the following detailed description of embodiments when read in conjunction with the accompanying drawing. In a drawing, like reference numerals refer to like elements. 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. ,CLAIMS:WE CLAIM:

1. A method for implementing adaptive filters in a de-interleaving process for known and unknown emitters, the method comprising:
providing an emitter parameter library comprising complete information of plurality of emitter pulse parameters of a plurality of known emitters;
receiving passively intercepted radar signals comprising a mixture of electromagnetic pulses transmitted from one or more radar sources;
determining a plurality of parameters of the received radar signals;
generating pulse descriptive words based on parameter values;
validating the pulse descriptive words for considering pulses that are not reflections;
sorting and grouping the pulse descriptive words based on the emitter pulse parameters corresponding to individual emitters that are active in a considered environment;
providing the pulse descriptive words to one or more first set of cells comprising one or more adaptive filters for processing;
adjusting limits of the one or more adaptive filters based on values of previous intercepts stored in the emitter parameter library;
determining if the provided pulse descriptive word belongs to a known radar based on the one or more pulse parameters;
generating a cell match signal upon determining that the provided pulse descriptive word belongs to a known radar;
displaying a track comprising statistical pulse descriptive word parameters and pulse repetition interval derived from the sequence of grouped pulse descriptive words;
providing the pulse descriptive words to a second set of cells comprising one or more adaptive filters, upon determining that the provided pulse descriptive word belongs to an unknown radar, for extracting emitter pulse parameters of the emitter that is the source of the radar signal;
assigning fixed tolerance values for each of the adaptive filters in the second set of cells for determining higher and lower limits;
extracting a plurality of parameters of the unknown radar by using the second set of the adaptive filters;
storing the extracted parameters from the radar signals of the unknown radar in the emitter parameter library; and
displaying a track comprising statistical pulse descriptive word parameters and pulse repetition interval derived from the sequence of grouped pulse descriptive word.

2. The method of claim 1, wherein the plurality of parameters are frequency, pulse width, pulse repetition interval, direction of arrival, amplitude, and scan period.

3. The method of claim 1, wherein the emitter parameter library comprises information about the parameters corresponding to known emitters.

4. The method of claim 1, wherein the pulse parameters for determining if the provided pulse descriptive word belongs to a known radar are frequency, pulse width, direction of arrival, time of arrival bits of the pulse descriptive word and pulse repetition interval value.

5. The method of claim 1, wherein each cell of the first set of cells allow multiple modes of a radar with multiple frequencies, pulse width & pulse repetition interval to be processed.

6. The method of claim 1, wherein the validation of the pulse descriptive word aids in accurate track formation by rejecting reflections causing low pulse width, low pulse repetition interval generation due to pulse breakage and interceptions in multiple directions with lower strength.

7. The method of claim 1, wherein the number of cells correspond to the number of radars that can be processed.

8. The method of claim 7, wherein the availability of number of cells for processing are programmable.