Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Priority
Acknowledgment is made of applicant’s claim for foreign priority under 35 U.S.C. 119 (a)-(d). The certified copy has been filed in parent Application No. KR 10-2024-0072681, filed on 06/03/2024.
Specification
Title: The title of the invention is not descriptive. A new title is required that is clearly indicative of the invention to which the claims are directed. The following title is suggested: Radar Apparatus and Method for Identifying Ghost Targets Using Virtual-Channel Side-Lobe Extraction or similar. See MPEP § 606.
Abstract: Applicant is reminded of the proper language and format for an abstract of the disclosure.
The abstract should be in narrative form and generally limited to a single paragraph on a separate sheet within the range of 50 to 150 words in length. The abstract should describe the disclosure sufficiently to assist readers in deciding whether there is a need for consulting the full patent text for details.
The language should be clear and concise and should not repeat information given in the title. It should avoid using phrases which can be implied, such as, “The disclosure concerns,” “The disclosure defined by this invention,” “The disclosure describes,” etc. In addition, the form and legal phraseology often used in patent claims, such as “means” and “said,” should be avoided. See MPEP § 608.01(b).
Objections: The disclosure is objected to because of the following informalities:
[0039]: “process the corresponding laser signal in a radar apparatus” appears to be an error for “radar signal.” The apparatus transmits and processes radar signals, not laser signals (cf. [0006], [0060]).
Fig. 7 description inconsistency: the Brief Description states FIG. 7 “illustrates an operation of creating an ULA from DCAs” ([0015]), while the Detailed Description states FIG. 7 “illustrates creation of DCAs” ([0109]). The two descriptions of the same figure are inconsistent and should be reconciled.
[0041]: the enumerated virtual-channel combination set is internally inconsistent — e.g., “{first virtual channel, third virtual channel}” and “{first virtual channel, fourth virtual channel}” are each listed twice, and several entries repeat. The combinatorial set should be corrected so the listed combinations are non-duplicative and consistent with the set recited in [0046].
[0085]: “connected to the plurality of receiving antennas 320 of 41 present disclosure” contains an apparent typographical error (“of 41 present” perhaps should be “of the present”).
Appropriate correction is required.
Claim Objections
Claim 6, 7, and 13-15 objected to because of the following informalities:
Claim 6 — “the side lobe is stored …” a side lobe is a radiation-pattern feature; what is stored is information indicating the presence/characteristics of the side lobe (see [0044-0045]). Recasting as “information about the side lobe is stored …” would improve precision (objection only; not relied on for a 35 U.S.C. 112(b) rejection).
Claim 7 — “the table” claim 6 introduces “a look-up table (LUT)”; claim 7 then refers to “the table.” For strict antecedent consistency, claim 7 should recite “the look-up table (LUT)” (or claim 6 should introduce “a table”).
Claims 13–15 — undefined acronym “DCA” is first spelled out (“difference co-arrangement”) in claim 6, but claims 13–15 descend from claim 1 (1→13→14→15) and never spell the acronym out in their own chain. “DCA” should be expanded at first use in claim 13.
Appropriate correction is required.
Claim Interpretation
The following is a quotation of 35 U.S.C. 112(f):
(f) Element in Claim for a Combination. – An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The following is a quotation of pre-AIA 35 U.S.C. 112, sixth paragraph:
An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
This application includes one or more claim limitations that do not use the word “means,” but are nonetheless being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, because the claim limitation(s) uses a generic placeholder that is coupled with functional language without reciting sufficient structure to perform the recited function and the generic placeholder is not preceded by a structural modifier. Such claim limitation(s) is/are: "extractor extracting a side lobe" in claims 1, 7, and 13.
Because this/these claim limitation(s) is/are being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, it/they is/are being interpreted to cover the corresponding structure described in the specification as performing the claimed function, and equivalents thereof.
If applicant does not intend to have this/these limitation(s) interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, applicant may: (1) amend the claim limitation(s) to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph (e.g., by reciting sufficient structure to perform the claimed function); or (2) present a sufficient showing that the claim limitation(s) recite(s) sufficient structure to perform the claimed function so as to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim1 rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 15 depends from claim 14 (chain 1→13→14→15) and recites “creating the plurality of DCAs based on the plurality of virtual channels.” Within that chain, claim 1 recites only “M number of predetermined virtual channels” and a “virtual channel combination”; “a plurality of virtual channels” is first introduced in claim 10, which is in a different branch (1→10) that claim 15 does not inherit. The phrase “the plurality of virtual channels” therefore lacks proper antecedent basis, rendering claim 15 indefinite.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1–5, 8, 9, and 13 are rejected under 35 U.S.C. 103 as being unpatentable over Wu et al. (US 2022/0094397 A1) in view of Lim et al. (US 2017/0168139 A1).
Regarding Claim 1, Wu et al. (’397) in view of Lim et al. (’139) teaches:
Wu et al. (’397) teaches: A radar apparatus comprising: (Abstract: “A radar system, apparatus, architecture, and method are provided … to construct a sparse MIMO virtual array aperture … to suppress spurious sidelobes caused by holes in the sparse MIMO virtual array aperture”; [0027]: the “distributed coherent radar system 100” under control of “radar controller processor 20”).
Wu et al. (’397) teaches: an antenna section comprising a plurality of transmitting antennas and a plurality of receiving antennas ([0022]: “Each distributed radar front-end RF MMIC device 10 includes one or more transmitting antenna elements TX and receiving antenna elements RX”; and “four transmitter modules 13 and six receiver modules 14”). Wu et al. (’397)’s plural transmitting antenna elements constitute the plurality of transmitting antennas, and its plural receiving antenna elements constitute the plurality of receiving antennas, together forming the antenna section.
Wu et al. (’397) teaches: an extractor extracting a side lobe based on a virtual channel combination comprising M number of predetermined virtual channels, where M is a natural number equal to or greater than 2, and angle information of a target ([0031]: “the i-th MIMO virtual array antenna element’s position may be denoted as x = n·d, where d is the unit element spacing”; [0029]: “a sparse bi-static MIMO array (e.g., contains holes or gaps), resulting in high grating lobes in the formed radar beam pattern … forward and backward difference co-array processing … for suppressing the spurious sidelobes”; [0020]: “extracting angle information from the difference co-array output vector by means of Fourier analysis (e.g., DFT or FFT) and peak detection”). Wu et al. (’397)’s sparse MIMO virtual array — a combination of plural (M ≥ 2) predetermined virtual array elements (e.g., the nine-element co-array constructed from a four-element sparse virtual array, [0035]) — is the virtual channel combination. The spurious sidelobes present in the difference co-array angle spectrum, which Wu et al. (’397) identifies as a function of the virtual array geometry and which appear at particular angles, are the side lobe; locating those spurious sidelobes in the angle spectrum (a prerequisite to Wu et al. (’397)’s suppression of them) constitutes extracting a side lobe based on the virtual channel combination and the angle information.
Wu et al. (’397) teaches the first portion of the signal-processor limitation: a signal processor controlling transmission and reception of a radar signal with respect to the target, and processing the radar signal based on the determination ([0023]: the “radar controller processing unit 20” is configured to “program the transmitter and receiver module 13, 14 to operate in a coordinated fashion by transmitting MIMO waveforms”; [0016]: “suppressing false detections due to spurious sidelobes”). Wu et al. (’397)’s radar controller processor commands transmission of the MIMO waveform, processes the corresponding reception, and acts on the identified spurious sidelobes.
Wu et al. (’397) does not explicitly teach, but Lim et al. (’139) teaches: if the side lobe is extracted, determining that a ghost target is detected by the radar signal ([0060]: “the determining unit 52 determines that the target by the corresponding lobe … is the grating lobe ghost when the calculated gain difference of each lobe is higher than the predetermined reference difference”; [0077]: the signal processing unit “determines that the target in front of the vehicle, which is positioned at the corresponding lobe angle, as the grating lobe ghost”). Lim et al. (’139) teaches that, upon identifying a lobe (a side/grating lobe) in the beamforming angle spectrum as satisfying the ghost criterion, the signal processing unit determines that the corresponding detection is a grating lobe ghost — i.e., a ghost target.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to configure Wu et al. (’397)’s radar controller processor, which already identifies the spurious sidelobes in the difference co-array angle spectrum, to determine that an extracted side lobe corresponds to a ghost target as taught by Lim et al. (’139). One would have been motivated to do so because Wu et al. (’397) recognizes that these spurious sidelobes produce “false detections” ([0016]) that degrade the false-detection rate, and Lim et al. (’139) supplies the specific gain-difference criterion ([0060], [0077]) for affirmatively classifying such a lobe as a grating lobe ghost, thereby converting Wu et al. (’397)’s sidelobe suppression into the explicit ghost-target determination that directly serves Wu et al. (’397)’s stated low-false-detection objective using the angle-spectrum data it already computes. There is a reasonable expectation of success because both references operate in the same field of vehicle MIMO radar angle estimation and form a digital-beamforming angle spectrum in which lobes are evaluated, and Lim et al. (’139) demonstrates that the gain-difference criterion reliably distinguishes a grating lobe ghost from a real target in an operative radar ([0077-0078]); the combination as a whole meets the limitation.
Regarding Claim 2, Wu et al. (’397) in view of Lim et al. (’139) teaches the radar apparatus according to Claim 1.
Wu et al. (’397) teaches: wherein the plurality of transmitting antennas are arranged to be spaced apart from each other by a predetermined separation distance of the transmitting antennas, and the plurality of receiving antennas are arranged to be spaced apart from each other by a predetermined separation distance of the receiving antennas ([0029]: “the spacing and arrangement of the transmitting and receiving antenna elements”; [0031]: “the i-th MIMO virtual array antenna element’s position may be denoted as x = n·d, where d is the unit element spacing in meters and n is an integer”). Wu et al. (’397) arranges its transmitting and receiving antenna elements at element positions that are integer multiples of the unit element spacing d, so that the transmitting antennas are spaced apart by a predetermined transmitting-antenna separation distance and the receiving antennas are spaced apart by a predetermined receiving-antenna separation distance.
Regarding Claim 3, Wu et al. (’397) in view of Lim et al. (’139) teaches the radar apparatus according to Claim 2.
Wu et al. (’397) teaches: wherein the predetermined separation distance of the transmitting antennas and the predetermined separation distance of the receiving antennas are set based on a unit separation distance, and the unit separation distance is set to be a half wavelength of a frequency of the radar signal transmitted by the transmitting antennas ([0031]: “d is the unit element spacing in meters … Ideally, d should be half wavelength for sampling the entire 180 degree field of view without ambiguity”). Wu et al. (’397) sets the antenna-element positions as integer multiples of the unit element spacing d and sets d to a half wavelength; the transmitting- and receiving-antenna separation distances are thus set based on the unit separation distance d, which is the half wavelength of the radar-signal frequency.
Regarding Claim 4, Wu et al. (’397) in view of Lim et al. (’139) teaches the radar apparatus according to Claim 1.
Wu et al. (’397) teaches: wherein the plurality of transmitting antennas and the plurality of receiving antennas are arranged on respective straight lines to be spaced apart from each other ([0030]: “linear array with equally spaced spatial samples are assumed”; [0031]: “the i-th MIMO virtual array antenna element’s position may be denoted as x = n·d”). Wu et al. (’397) arranges its array elements as a linear array along a line at positions n·d spaced apart from one another, whereby the transmitting antennas and the receiving antennas are arranged on respective straight lines and spaced apart.
Regarding Claim 5, Wu et al. (’397) in view of Lim et al. (’139) teaches the radar apparatus according to Claim 1.
Wu et al. (’397) teaches: wherein the antenna section comprises four transmitting antennas and four receiving antennas, and has a sparse linear arrangement (SLA) structure ([0022]: “four transmitter modules 13” and “four receiver modules”; [0029]: “a sparse bi-static MIMO array (e.g., contains holes or gaps)”; [0035]: “constructed from the four (4) element sparse MIMO virtual array”). Wu et al. (’397) expressly discloses four transmitter modules and four receiver modules and a sparse (non-uniformly spaced) linear MIMO array, which is the sparse linear arrangement (SLA) structure. To the extent the precise pairing of exactly four transmitting and exactly four receiving antennas is presented among Wu et al. (’397)’s several disclosed element counts, selecting four transmitting and four receiving antennas is a routine choice among the finite, expressly enumerated alternatives of Wu et al. (’397), yielding no more than the predictable result of its sparse MIMO virtual array.
Regarding Claim 8, Wu et al. (’397) in view of Lim et al. (’139) teaches the radar apparatus according to Claim 1.
Claim 8 recites the alternative “at least one of an azimuth angle or an elevation angle.” Per MPEP § 2111.04, the art need teach only one alternative; the Examiner relies on the azimuth angle alternative.
Wu et al. (’397) teaches: wherein the angle information comprises at least one of an azimuth angle or an elevation angle ([0027]: the radar controller computes a target map “to identify the range, Doppler, and angle values”; FIGS. 5A–5B, plotting beamforming output against the “AZIMUTH DIRECTION (DEG)”). Wu et al. (’397)’s angle values are determined along the azimuth direction, so the angle information comprises an azimuth angle.
Regarding Claim 9, Wu et al. (’397) in view of Lim et al. (’139) teaches the radar apparatus according to Claim 1.
Wu et al. (’397) teaches: wherein the angle information is determined based on the radar signal received by being reflected by the target and a fast Fourier transform (FFT) algorithm ([0020]: “extracting angle information from the difference co-array output vector by means of Fourier analysis (e.g., DFT or FFT) and peak detection”; [0027]: the digital output signals derived from the received target returns are processed by the “spatial (angle) FFT module 27”). Wu et al. (’397) determines the angle information from the received reflected radar returns by applying an FFT, meeting the limitation.
Regarding Claim 13, Wu et al. (’397) in view of Lim et al. (’139) teaches the radar apparatus according to Claim 1.
Wu et al. (’397) teaches: wherein the extractor extracts the side lobe based on the angle information and a DCA combination ([0029]: “forward and backward difference co-array processing … for suppressing the spurious sidelobes”; [0030]: the radar controller “construct[s] the difference co-array 203”; [0020]: “extracting angle information from the difference co-array output vector by means of Fourier analysis (e.g., DFT or FFT)”). In Wu et al. (’397), the spurious sidelobes are present in, and identified from, the difference co-array (DCA) angle spectrum; the side lobe is thus extracted based on the angle information and the difference co-array combination.
Claims 6 and 7 are rejected under 35 U.S.C. 103 as being unpatentable over Wu et al. (US 2022/0094397 A1) in view of Lim et al. (US 2017/0168139 A1) and further in view of Godfrey et al. (US 7,541,970 B1).
Claims 6 and 7 each recite “at least one of the angle information, the virtual channel combination, or a difference co-arrangement (DCA) combination.” The Examiner relies on the angle information alternative; under MPEP § 2111.04 only one alternative need be taught.
Regarding Claim 6, Wu et al. (’397) in view of Lim et al. (’139) and further in view of Godfrey et al. (’970) teaches the radar apparatus according to Claim 1.
Wu et al. (’397) teaches pre-computing and storing, for subsequent retrieval, reference quantities that are a deterministic function of the array/co-array geometry ([0040]: “the average values can be calculated and stored for subsequent retrieval and use”).
Wu et al. (’397) does not explicitly teach, but Godfrey et al. (’970) teaches: wherein the side lobe is stored in a look-up table (LUT) in a manner corresponding to at least one of the angle information, the virtual channel combination, or a difference co-arrangement (DCA) combination (col. 5, lines 1-14, Detector 24, Fig. 3A: “Various techniques (e.g., using detection data tables referenced by range, azimuth angle, and/or radome angle …) can be used to determine when spurious signals are above a desired level”; col. 4, lines 40-51: “The spurious signals from beams 22 are generally side lobes and lobe reflections”). Godfrey et al. (’970) stores side-lobe/spurious-signal detection data in detection data tables (a look-up table) that are referenced (indexed) by azimuth angle — i.e., side-lobe information stored in a manner corresponding to the angle information.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to store the side-lobe information of Wu et al. (’397) (as modified by Lim et al. (’139)) in a look-up table indexed by angle information, as taught by Godfrey et al. (’970). One would have been motivated to do so because Wu et al. (’397) treats the spurious sidelobes as a fixed function of the array/co-array geometry and already stores geometry-dependent reference quantities “calculated and stored for subsequent retrieval and use” ([0040]) to avoid redundant real-time computation, and Godfrey et al. (’970) supplies the concrete data structure — detection data tables referenced by azimuth angle — so the angle-indexed side-lobe values can be looked up rather than recomputed each scan, reducing the per-frame processing burden consistent with Wu et al. (’397)’s express efficiency concern. There is a reasonable expectation of success because Godfrey et al. (’970) demonstrates angle-indexed detection-data tables operating to flag side-lobe/spurious returns in an operative radar, and the side-lobe values in Wu et al. (’397) are fixed functions of geometry and angle and thus amenable to pre-computation and tabulated storage; the combination as a whole meets the limitation.
Regarding Claim 7, Wu et al. (’397) in view of Lim et al. (’139) and further in view of Godfrey et al. (’970) teaches the radar apparatus according to Claim 6.
Wu et al. (’397) (as modified) stores the side-lobe information per claim 6 but does not explicitly teach the retrieval step. Wu et al. (’397) does not explicitly teach, but Godfrey et al. (’970) teaches: wherein the extractor retrieves, from the table, the side lobe stored in a manner corresponding to at least one of the virtual channel combination, the angle information of the target, or the DCA combination (col. 5, lines 1-14: detection data tables “referenced by range, azimuth angle, and/or radome angle”). Godfrey et al. (’970)’s act of referencing the detection data table by azimuth angle to determine whether a spurious side-lobe signal is present is a retrieval, from the table, of the side-lobe information stored in correspondence with the angle information.
It would have been obvious, and for the same reasons set forth for claim 6, to have Wu et al. (’397)’s extractor retrieve the angle-indexed side-lobe value from Godfrey et al. (’970)’s look-up table. One would have been motivated to do so because retrieval-by-angle is the necessary and intended use of the angle-referenced table taught by Godfrey et al. (’970), and it avoids recomputing the geometry-fixed side-lobe values each frame — the same efficiency rationale Wu et al. (’397) articulates at [0040]. There is a reasonable expectation of success because Godfrey et al. (’970) demonstrates that referencing such a table by azimuth angle reliably yields the corresponding spurious-signal determination in an operative radar. The combination as a whole meets the limitation.
Claims 10–12, 14, and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Wu et al. (US 2022/0094397 A1) in view of Lim et al. (US 2017/0168139 A1) and further in view of Liu et al. (IEEE Trans. Signal Process., vol. 67, 2019).
Regarding Claim 10, Wu et al. (’397) in view of Lim et al. (’139) and further in view of Liu et al. teaches the radar apparatus according to Claim 1.
Wu et al. (’397) teaches forming a virtual channel combination from the available plurality of virtual array elements ([0031]: virtual array element positions “xi = ni*d”; [0035]: a co-array “constructed from the four (4) element sparse MIMO virtual array”).
Wu et al. (’397) does not explicitly teach, but Liu et al. teaches: wherein the virtual channel combination is one of virtual channel combinations, in which the M number of virtual channels is randomly extracted from a plurality of virtual channels (p. 3216: the family of all size-k subarrays – equation 6 “”; p. 3213: “sensor failure could occur randomly”, whereby a random subset of the array elements remains and its (difference co-)array is evaluated). Liu et al. teaches that a size-k (here, size-M) subset extracted — including randomly — from the full set of array elements is a recognized array configuration whose array output is analyzed.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to form Wu et al. (’397)’s virtual channel combination as a size-M subset randomly extracted from its plurality of virtual channels, as taught by Liu et al. One would have been motivated to do so because Liu et al. teaches that the difference co-array — the structure Wu et al. (’397) relies upon for angle estimation and sidelobe behavior — is well-defined for arbitrary size-k subsets of the array, including randomly determined ones (p. 3213; p. 3216), so a designer of Wu et al. (’397)’s system would recognize that any randomly extracted M-element subset of the virtual channels yields an operative virtual channel combination; random extraction is, moreover, selection of one configuration from a finite set of identified subsets for which the applicant has shown no criticality, making it an obvious design choice. There is a reasonable expectation of success because Liu et al. rigorously establishes that the difference co-array, and hence the angle-estimation framework Wu et al. (’397) employs, remains well-defined and analyzable for randomly determined subsets (p. 3213; p. 3215); the combination as a whole meets the limitation.
Regarding Claim 11, Wu et al. (’397) in view of Lim et al. (’139) and further in view of Liu et al. teaches the radar apparatus according to Claim 10.
Wu et al. (’397) teaches: wherein the plurality of virtual channels are created based on at least one of a predetermined separation distance of the transmitting antennas or a predetermined separation distance of the receiving antennas ([0023]: “transmitting MIMO waveforms for use in constructing a virtual aperture from a combination of the distributed apertures formed by the distributed transmitting and receiving antenna elements”; [0031]: virtual array element positions “xi = ni*d, where d is the unit element spacing”). In Wu et al. (’397)’s MIMO virtual array, the virtual channels (virtual array elements) are created from the physical transmitting and receiving antenna elements and their separation distances (the unit element spacing d), satisfying this limitation under the recited “or” alternative.
Regarding Claim 12, Wu et al. (’397) in view of Lim et al. (’139) and further in view of Liu et al. teaches the radar apparatus according to Claim 10.
Wu et al. (’397) teaches: wherein the number of the plurality of virtual channels is determined based on the number of the plurality of transmitting antennas and the number of the plurality of receiving antennas ([0028]: “an extended MIMO aperture can be formed based on MIMO radar principles”; [0023]: the virtual aperture is “a combination of the distributed apertures formed by the distributed transmitting and receiving antenna elements”). Under MIMO radar principles as taught by Wu et al. (’397), the MIMO virtual array is formed from the combination of the transmitting and receiving antenna elements, such that the number of virtual channels is determined by the number of transmitting antennas and the number of receiving antennas.
Regarding Claim 14, Wu et al. (’397) in view of Lim et al. (’139) and further in view of Liu et al. teaches the radar apparatus according to Claim 13.
Wu et al. (’397) teaches constructing a plurality of difference co-array (DCA) elements ([0033-0035]: “the difference spacing from all combinations are listed” and “a difference co-array aperture of the size of nine (9) elements”).
Wu et al. (’397) does not explicitly teach, but Liu et al. teaches: wherein the DCA combination is one of DCA combinations in which K number of DCAs are randomly extracted from a plurality of DCAs, wherein K is a natural number equal to or greater than 2 (p. 3215, Definition 1: “The difference coarray of a linear array S is defined as ; p. 3216: equation 6; p. 3213: “sensor failure could occur randomly”). Liu et al. teaches that a size-K (K ≥ 2) subset of the difference-co-array elements, including a randomly extracted subset, is a recognized configuration whose co-array is analyzed.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to form Wu et al. (’397)’s DCA combination as a size-K (K ≥ 2) subset randomly extracted from its plurality of DCAs, as taught by Liu et al. One would have been motivated to do so for the same reasons set forth for claim 10: Liu et al. establishes that the difference co-array is well-defined for arbitrary and randomly determined size-k subsets (p. 3213; p. 3216), so a designer of Wu et al. (’397)’s difference-co-array radar would recognize a randomly extracted K-element subset of the DCA as an operative DCA combination, and random selection from the finite, identified set of DCA subsets is an obvious design choice absent a showing of criticality. There is a reasonable expectation of success because Liu et al. rigorously establishes that the difference co-array remains well-defined and analyzable for such subsets (p. 3215). The combination as a whole meets the limitation.
Regarding Claim 15, Wu et al. (’397) in view of Lim et al. (’139) and further in view of Liu et al. teaches the radar apparatus according to Claim 14.
Wu et al. (’397) teaches creating the plurality of DCAs based on the plurality of virtual channels ([0030]: “construct the difference co-array 203 by filling the gaps in the MIMO virtual array 202”; [0035]: the difference co-array is “constructed from the … sparse MIMO virtual array”); Wu et al. (’397) thereby creates the plurality of difference co-array elements (DCAs) based on the plurality of virtual channels.
Wu et al. (’397) does not explicitly teach, but Liu et al. teaches: removing one DCA having a non-uniform DCA spacing from the plurality of DCAs, and creating a uniform linear arrangement (ULA) from the remaining DCAs (p. 3215: “The central ULA segment of D, denoted by U, is the longest ULA in D that includes the entry 0”; and “A difference coarray is hole-free if D = U”). Liu et al. teaches that the difference co-array generally contains non-uniformly spaced elements outside the central uniform segment, and that the operative uniform linear array (ULA) is obtained as the central ULA segment U — i.e., by retaining the uniformly spaced co-array elements and excluding those that, by reason of holes, are non-uniformly spaced.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to process Wu et al. (’397)’s difference co-array by removing a non-uniformly spaced DCA element and forming a uniform linear arrangement from the remaining elements, as taught by Liu et al.’s central ULA segment. One would have been motivated to do so because Wu et al. (’397) requires a uniformly spaced co-array for its downstream processing — performing spatial smoothing only “if the formed difference co-array is uniformly spaced” ([0029]) and assuming “equally spaced spatial samples” ([0030]) — and Liu et al. supplies the recognized technique for obtaining such a uniform array from a sparse-array co-array, namely extracting the central ULA segment by excluding the non-uniformly spaced (hole-bearing) elements (p. 3215), which predictably yields the uniformly spaced co-array Wu et al. (’397)’s spatial smoothing and angle estimation require. There is a reasonable expectation of success because Liu et al. rigorously defines the difference co-array, its holes, and its central ULA segment for sparse arrays of the type Wu et al. (’397) employs (p. 3215), and removing a non-uniformly spaced element to leave a ULA is a deterministic, well-defined operation on the co-array; the combination as a whole meets the limitation.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Lee (’346) (US 2019/0310346 A1) and Ebling (’608) (US 2016/0252608 A1) were considered but are not relied upon because they are cumulative to the references applied above. Lee (’346)’s teaching of ghost-target determination from virtual (M+N)-channel array signals is supplied more completely by Wu et al. (’397) (sparse MIMO virtual array / difference co-array) in combination with Lim et al. (’139) (grating-lobe ghost determination), and Ebling (’608)’s teaching of grating-lobe false targets in array-antenna radar is cumulative to Lim et al. (’139).
Any inquiry concerning this communication or earlier communications from the examiner should be directed to REMASH R GUYAH whose telephone number is (571)270-0115. The examiner can normally be reached M-F 7:30-4:30.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Resha H Desai can be reached at (571) 270-7792. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/REMASH R GUYAH/Examiner, Art Unit 3648
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