Prosecution Insights
Last updated: April 19, 2026
Application No. 18/304,166

MIXED-MODE DISTRIBUTED COHERENT APERTURE TECHNIQUE FOR ERROR MITIGATION

Final Rejection §101§103
Filed
Apr 20, 2023
Examiner
HODAC, ERIC KHOI
Art Unit
3648
Tech Center
3600 — Transportation & Electronic Commerce
Assignee
Government Of The United States AS Represented By The Secretary Of The Air Force
OA Round
2 (Final)
84%
Grant Probability
Favorable
3-4
OA Rounds
3y 2m
To Grant
99%
With Interview

Examiner Intelligence

Grants 84% — above average
84%
Career Allow Rate
52 granted / 62 resolved
+31.9% vs TC avg
Strong +20% interview lift
Without
With
+19.5%
Interview Lift
resolved cases with interview
Typical timeline
3y 2m
Avg Prosecution
28 currently pending
Career history
90
Total Applications
across all art units

Statute-Specific Performance

§101
1.5%
-38.5% vs TC avg
§103
50.3%
+10.3% vs TC avg
§102
29.3%
-10.7% vs TC avg
§112
19.0%
-21.0% vs TC avg
Black line = Tech Center average estimate • Based on career data from 62 resolved cases

Office Action

§101 §103
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 . Response to Amendment The amendment filed January 8, 2026 has been entered. Claims 1-2, 4-15, and 17-20 remain pending in this application. Claims 1 and 15 have been amended. Claims 3 and 16 have been cancelled. Response to Arguments Regarding Applicant’s remarks about the 35 U.S.C. 101 rejection to claims 8-14 set forth in the Non-Final Rejection filed August 13, 2025, Examiner has included further explanation of the rejection below. Regarding Applicant’s arguments concerning the now amended subject matter of claims 1 and 15, Examiner asserts that Nanzer et al. does teach wherein the coherence parameter tolerance can be adjusted by adjusting the size of the sub-array, citing page 1666, “The requirements on the errors of the phase, range, and angle parameters in a coherent distributed array vary depending on the number of nodes in the array, the level of coherent gain desired, and the desired probability of achieving the coherent gain. For probabilities above approximately 0.8, increasing the number of nodes in the array reduces the error requirements [greater error per node can be tolerated], however, for probabilities below 0.8, the opposite is true.”, where Examiner notes that errors of phase, range, and angle parameters in a coherent distributed array are coherence parameters, and the error requirements are a tolerance thereof. Claim Rejections - 35 USC § 101 35 U.S.C. 101 reads as follows: Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title. Claims 8-14 are rejected under 35 U.S.C. 101 because the claimed invention is directed to non-statutory subject matter. The claims do not fall within at least one of the four categories of patent eligible subject matter because they are directed to a "machine-readable storage medium" which can be interpreted as a signal per se, which is not one of the four statutory categories. Applicant’s specification in paras. 63-65 lists examples of a machine-readable storage medium. However, the examples listed don’t completely exclude transitory embodiments. Therefore, Examiner is interpreting the machine-readable medium as encompassing transitory signals and non-transitory embodiments. Claim 8-14 are therefore rejected under 35 U.S.C. 101 for including transitory signals under its scope. Applicant can overcome this rejection by adding the modifier "non-transitory" before “machine-readable storage medium”. 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. Claims 1-7 and 15-20 are rejected under 35 U.S.C. 103 as being unpatentable over Gao et al. (Study on Distributed Aperture Coherence-synthesizing Radar with Several Experiment Results [2011]), hereinafter Gao, in view of Nanzer et al. (Open-Loop Coherent Distributed Arrays [2017]), hereinafter Nanzer. Regarding claims 1 and 15, Gao teaches a method and system respectively, comprising: receiving, by a plurality of receivers, a combination of separable transmit waveforms from a plurality of transmitters wherein the plurality of transmitters are grouped into a sub-array (Fig. 1, transmitting sub-arrays are shown; Fig. 2, multiple unit radars transmitting and receiving), processing, by each receiver of the plurality of receivers, the combination of separable transmit waveforms to estimate coherence parameters associated with each separable transmit waveform of the combination of separable transmit waveforms (para. 2.1, “The distributed aperture coherence-synthesizing radar transmits orthogonal waveforms [noise-like] to search about the location of the external cue with long integration periods for the target acquisition. Once a stable track is obtained, N2 SNR [signal-to-noise ratio] gain is achieved over a single aperture when the orthogonal waveforms are combined coherently, called cohere-on-receive mode for adaptively and precisely estimating the coherence parameters [including delay and phase];”), based on an estimation of the coherence parameters, determining, by each receiver of the plurality of receivers, a signal model of a next set of transmissions of the separable transmit waveforms transmitted by the plurality of transmitters (para. 2.1, “As the track progresses, if the transmit coherence parameters of high quality is obtained, like waveforms are used and the relative phase and transmit time of each transmit pulse is adaptively and carefully adjusted so that the transmitted pulses arrive at the target in-phase and at the same time, while N3 SNR gain is achieved over a single aperture, called full coherence mode both on transmit and receive, as shown in Fig. 2.”), processing, by a processor, the signal model according to a mixed-mode distributed coherent radar operating mode that is a function of coherence parameter errors (para. 1, “Distributed aperture coherence-synthesizing radar system, proposed by MIT Lincoln Laboratory for the important direction of Next Generation Radar [NGR], consists of several unit radars with smaller apertures and a central controlling and processing system as shown in Fig.1.”; para. 2.1, “As the track progresses, if the transmit coherence parameters of high quality is obtained, like waveforms are used and the relative phase and transmit time of each transmit pulse is adaptively and carefully adjusted so that the transmitted pulses arrive at the target in-phase and at the same time, while N3 SNR gain is achieved over a single aperture, called full coherence mode both on transmit and receive, as shown in Fig. 2.”), and sending the processed signal model to the plurality of transmitters for each transmitter of the plurality of transmitters to generate its own separable transmit waveform selected from the separable waveforms for transmission (para. 2.1, “As the track progresses, if the transmit coherence parameters of high quality is obtained, like waveforms are used and the relative phase and transmit time of each transmit pulse is adaptively and carefully adjusted so that the transmitted pulses arrive at the target in-phase and at the same time, while N3 SNR gain is achieved over a single aperture, called full coherence mode both on transmit and receive, as shown in Fig. 2.”), but fails to teach coherence parameter errors associated with each separable transmit waveform and a size of the sub-array, wherein the coherence parameter errors comprise errors of the plurality of transmitters and the plurality of receivers, and wherein the signal model comprises a coherence parameter tolerance of a radar system comprising the plurality of transmitters and the plurality of receivers wherein the coherence parameter tolerance can be adjusted by adjusting the size of the sub-array. However, Nanzer teaches coherence parameter errors associated with each separable transmit waveform and a size of the sub-array, wherein the coherence parameter errors comprise errors of the plurality of transmitters and the plurality of receivers, and wherein the signal model comprises a coherence parameter tolerance of a radar system comprising the plurality of transmitters and the plurality of receivers wherein the coherence parameter tolerance can be adjusted by adjusting the size of the sub-array (page 1666, “The requirements on the errors of the phase, range, and angle parameters in a coherent distributed array vary depending on the number of nodes in the array, the level of coherent gain desired, and the desired probability of achieving the coherent gain. For probabilities above approximately 0.8, increasing the number of nodes in the array reduces the error requirements [greater error per node can be tolerated], however, for probabilities below 0.8, the opposite is true. […] The tolerances on phase error, as shown in Fig. 4, indicate that as the number of platforms in the array approaches infinity, the standard deviation of the phase error between any two nodes cannot exceed 18◦.”; page 1668, “The waveforms were transmitted from one platform and were co-operatively reflected back to the transceiver using a corner cube reflector (in a practical system a retrodirective system or communications link would be used in place of a corner cube). Fig. 7 shows the measured ranging performance of the system as a function of tone separation.”; see Gao para. 2.1 and Fig. 2 for coherence parameter estimation of sub-arrays). Gao and Nanzer are considered to be analogous to the claimed invention because they are in the same field of coherent radar array systems. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Gao with the teachings of Nanzer, with the motivation of being able to define an acceptable degree of coherence. Regarding claim 2, Gao in view of Nanzer teaches the method of claim 1, further comprising transmitting a separable transmit waveform from each of the plurality of transmitters, wherein each transmitter of the plurality of transmitters transmits its own separable transmit waveform independent of separable transmit waveforms transmitted from other transmitters of the plurality of transmitters (Gao; Figs. 1 and 2, separate transmitting arrays are shown; see Nanzer page 1662 for further evidence of waveforms transmitted by multiple separate radar systems). Regarding claims 4 and 17, Gao in view of Nanzer teaches the method of claim 1 and the system of claim 15 respectively, wherein the processed signal model instructs the radar system to operate in the mixed-mode distributed coherent radar operating mode, a cohere-on-transmit (COT) operating mode, or a cohere-on-receive (COR) operating mode (Gao; Fig. 2, cohere-on-receive and full coherence modes). Regarding claims 5 and 18, Gao in view of Nanzer teaches the method of claim 1 and the system of claim 15 respectively, wherein the processed signal model provides operating instructions to the radar system on how to collectively improve system performance of the radar system given a current state of the coherence parameter errors (Gao; para. 2.1, “As the track progresses, if the transmit coherence parameters of high quality is obtained, like waveforms are used and the relative phase and transmit time of each transmit pulse is adaptively and carefully adjusted so that the transmitted pulses arrive at the target in-phase and at the same time, while N3 SNR gain is achieved over a single aperture, called full coherence mode both on transmit and receive, as shown in Fig. 2.”). Regarding claims 6 and 19, Gao in view of Nanzer teaches the method of claim 5 and the system of claim 18 respectively, wherein the operating instructions comprise selectively choosing different combinations of the separable transmit waveforms for transmission by each transmitter (Gao; para. 2.1, “Once a stable track is obtained, N2 SNR [signal-to-noise ratio] gain is achieved over a single aperture when the orthogonal waveforms are combined coherently, called cohere-on-receive mode for adaptively and precisely estimating the coherence parameters [including delay and phase]; As the track progresses, if the transmit coherence parameters of high quality is obtained, like waveforms are used and the relative phase and transmit time of each transmit pulse is adaptively and carefully adjusted so that the transmitted pulses arrive at the target in-phase and at the same time, while N3 SNR gain is achieved over a single aperture, called full coherence mode both on transmit and receive, as shown in Fig. 2.”; Fig. 2, multiple unit radars are used, each undergoing orthogonal transmit waveform selection). Regarding claims 7 and 20, Gao in view of Nanzer teaches the method of claim 1 and the system of claim 15 respectively, but Gao fails to teach wherein determining the signal model comprises performing an analysis of the number of radars in the radar system vs. a coherence parameter error tolerance of the radar system. However, Nanzer teaches wherein determining the signal model comprises performing an analysis of the number of radars in the radar system vs. a coherence parameter error tolerance of the radar system (page 1666, “The requirements on the errors of the phase, range, and angle parameters in a coherent distributed array vary depending on the number of nodes in the array, the level of coherent gain desired, and the desired probability of achieving the coherent gain. For probabilities above approximately 0.8, increasing the number of nodes in the array reduces the error requirements [greater error per node can be tolerated], however, for probabilities below 0.8, the opposite is true.”; see Gao para. 2.1 and Fig. 2 for coherence parameter estimation of sub-arrays). Gao and Nanzer are considered to be analogous to the claimed invention because they are in the same field of coherent radar array systems. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Gao with the teachings of Nanzer, with the motivation of being able to define an acceptable degree of coherence. Conclusion THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action. Any inquiry concerning this communication or earlier communications from the examiner should be directed to ERIC K HODAC whose telephone number is (571) 270-0123. The examiner can normally be reached M-Th 8-6. 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, VLADIMIR MAGLOIRE can be reached at (571) 270-5144. 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. /ERIC K HODAC/Examiner, Art Unit 3648 /VLADIMIR MAGLOIRE/Supervisory Patent Examiner, Art Unit 3648
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Prosecution Timeline

Apr 20, 2023
Application Filed
Aug 07, 2025
Non-Final Rejection — §101, §103
Jan 08, 2026
Response Filed
Mar 06, 2026
Final Rejection — §101, §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
84%
Grant Probability
99%
With Interview (+19.5%)
3y 2m
Median Time to Grant
Moderate
PTA Risk
Based on 62 resolved cases by this examiner. Grant probability derived from career allow rate.

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