DETAILED ACTION
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 .
Status of Claims
Claims 1-20 are currently pending and have been examined.
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 10/17/2024 has been considered by the examiner and an initialed copy of the IDS is hereby attached.
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.
Claims 4, 10 and 17 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.
Regarding claim 4, the limitation “determining that the second signal is a cross-correlation source associated with a detection associated with a second satellite”. This limitation is indefinite as the second signal is a signal of the first satellite (as recited in claim 1) and therefore cannot also be “a cross-correlation source associated with a detection associated with a second satellite”. Claim 4 contradicts claim 1 and therefore is indefinite as the metes and bounds of the claim cannot be ascertained.
Regarding claim 10, the limitation “selecting the second signal to be a tracked signal; performing tracking on the second signal and determining a calibration measurement associated with the second signal;”, this limitation is indefinite as the second signal has been untracked in claim 1 and therefore the second signal can not be a tracked signal and an untracked signal simultaneously. Claim 10 contradicts claim 1 and therefore is indefinite as the metes and bounds of the claim cannot be ascertained. Claim 17 is rejected under the same rationale as claim 1.
Allowable Subject Matter
Claims 12 and 19 objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
The following is a statement of reasons for the indication of allowable subject matter:
In reference to claims 12 and 19, the prior arts made of record individually or in any combination, failed to teach, render obvious, or fairly suggest to one of ordinary skill in the art at the time of filing the combination of the claimed features of claims 12 and 19.
Claim Rejections - 35 USC § 102
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claim(s) 1-7,10-11,13-18 and 20 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Tangudu et al. (US 20110103432 A1).
Regarding claim 1, Tangudu discloses
A method for cross-correlation detection (see Abstract), the method comprising:
receiving, by a receiver, a first signal of a first satellite and a second signal of the first satellite (see Fig. 2, receiver 100 receives a plurality of signals from SV1 (i.e. satellite 1) further see Fig. 8);
selecting, by the receiver, the first signal to be a tracked signal (see Fig. 11A, further see paragraph 0140, “In FIG. 11A, a process embodiment performed in the structures of FIG. 11 checks whether a peak is a true peak or a cross correlation peak….A further decision step 560 determines whether the computed amount of cross correlation is sufficient to indicate that the peak is a cross correlation peak or is uselessly corrupted by cross correlation. If not, the peak is regarded as a valid peak and operations proceed to Signal Detected step 570 to log the peak is valid and utilize it for positioning purposes.”, where logging the peak as a valid peak and using it for positioning purposes is indeed “selecting” the signal to be a tracked signal);
selecting, by the receiver, the second signal to be an untracked signal (see Fig. 11A, further see paragraph 0140, “In FIG. 11A, a process embodiment performed in the structures of FIG. 11 checks whether a peak is a true peak or a cross correlation peak….A further decision step 560 determines whether the computed amount of cross correlation is sufficient to indicate that the peak is a cross correlation peak or is uselessly corrupted by cross correlation. If not, the peak is regarded as a valid peak and operations proceed to Signal Detected step 570 to log the peak is valid and utilize it for positioning purposes. If Yes in decision step 560, operations proceed to step 580 to disregard the peak, or remove a speculative entry for the peak if it was entered on a list of valid peaks, or enter the status of the peak as a Invalid. Operations loop back to step 520.”, where disregarding the peak and removing is from speculative entry is indeed “selecting” the signal to be an untracked signal);
tracking, by the receiver, the first signal (see Fig. 11A, further see paragraph 0140, “In FIG. 11A, a process embodiment performed in the structures of FIG. 11 checks whether a peak is a true peak or a cross correlation peak. In a step 510, integration operations over a latest dwell interval in FIGS. 5 and 25 are completed. Then a step 520 finds the largest peak and computes relevant peak statistics. A succeeding decision step 530 determines whether the signal represented by that peak exceeds a detection threshold”);
generating, by the receiver, a first measurement based on the tracking of the first signal (see paragraph 0136, “A conservative Approach 1 to cross correlation mitigation might operate so that if a low power SV signal is detected with the Doppler shift of its 1.575 GHz carrier at close to a multiple of one kHz (because the periodicity is 1 ms which corresponds to 1/1 ms=1 kHz) away from the carrier Doppler of a high power SV, and if the C/N.sub.o difference between SV1 and SV2 is greater than a static threshold (18 db Hz), the signal is assumed to be a cross correlation peak and rejected. (The expression C/N.sub.o signifies the ratio of Carrier signal power C for the SV to Noise Spectral Density N.sub.o.”, where the C/N.sub.o of SV1 is the first measurement);
determining, by the receiver, a second measurement of the second signal based on the first measurement (see paragraph 0136, “A conservative Approach 1 to cross correlation mitigation might operate so that if a low power SV signal is detected with the Doppler shift of its 1.575 GHz carrier at close to a multiple of one kHz (because the periodicity is 1 ms which corresponds to 1/1 ms=1 kHz) away from the carrier Doppler of a high power SV, and if the C/N.sub.o difference between SV1 and SV2 is greater than a static threshold (18 db Hz), the signal is assumed to be a cross correlation peak and rejected. (The expression C/N.sub.o signifies the ratio of Carrier signal power C for the SV to Noise Spectral Density N.sub.o.”, where the first measurement is the C/N.sub.o value of SV1 and the “the C/N.sub.o difference between SV1 and SV2 is greater than a static threshold (18 db Hz)” is the second measurement); and
performing an operation on the receiver based on the second measurement (see Fig. 11A, further see paragraph 0140, “In FIG. 11A, a process embodiment performed in the structures of FIG. 11 checks whether a peak is a true peak or a cross correlation peak….A further decision step 560 determines whether the computed amount of cross correlation is sufficient to indicate that the peak is a cross correlation peak or is uselessly corrupted by cross correlation. If not, the peak is regarded as a valid peak and operations proceed to Signal Detected step 570 to log the peak is valid and utilize it for positioning purposes.”, where “utilizing it for positioning purposes” is indeed “performing an operation on the receiver based on the second measurement”).
Regarding claim 2, Tangudu further discloses
The method of claim 1, wherein:
the tracking the first signal comprises tracking, by the receiver, a carrier of the first signal and tracking, by the receiver, a code of the tracked signal (see paragraph 0106, “In FIGS. 11, 16 and 20, among other Figures, structure and process embodiments for implementing Mechanism 1 herein compute the cross correlation coefficient between the two PN codes of SV1 and SV2 at the relative carrier Doppler f1-f2 and at the relative peak location c.sub.1-c.sub.2 between the low-power peak and the high power peak.”); and
being untracked comprises not tracking, by the receiver, a carrier of the untracked signal and/or not tracking, by the receiver, a code of the untracked signal (see paragraph 0107, “Suppose a low power correlation peak is found at code phase c1 for Satellite SV1, Doppler f1, and the receiver already detected a high power peak from another SV2 at code phase c2, Doppler f2. Such a Mechanism herein computes an estimated cross correlation coefficient at code phase difference c1-c2 at Doppler difference f1-f2 using a dedicated hardware unit and then compares the estimated cross correlation coefficient with the actual low power peak to judge whether the low power peak is a cross correlation peak or not. Also, during tracking of the low power peak the cross correlation coefficient is also computed in some embodiments to ensure that the measurements are valid. In the event of a cross correlation peak smearing the low power peak, this can be calculated beforehand and the measurements rejected.”).
Regarding claim 3, Tangudu further discloses
The method of claim 2, wherein the carrier includes at least one of a signal carrier frequency or a signal carrier phase (see paragraph 0106, “In FIGS. 11, 16 and 20, among other Figures, structure and process embodiments for implementing Mechanism 1 herein compute the cross correlation coefficient between the two PN codes of SV1 and SV2 at the relative carrier Doppler f1-f2 and at the relative peak location c.sub.1-c.sub.2 between the low-power peak and the high power peak.”).
Regarding claim 4, Tangudu further discloses
The method of claim 1, wherein the operation comprises determining that the second signal is a cross-correlation source associated with a detection associated with a second satellite (see paragraph 0093, “In FIG. 5, the Tracking section is also subject to cross-correlation peaks between SV1 and SV2 being confused with actual lower power SV1 to be tracked. When a substantial correlation (a peak) is detected in the Tracking section, then this peak may represent useful information from the actual SV1. Unfortunately, with a low power signal received from a satellite SV1 for which the code lag c.sub.1 is to be measured, confusion can arise because of cross correlation of the Gold code P1 fed to the correlator to search for SV1 with the Gold code P2 arriving on the high power signal from SV2. The tracking DLL might undesirably lock onto the cross correlation peak or lobe. Embodiments such as cross-correlation mitigation hardware Xcorr 400 to mitigate this cross correlation in the Tracking section as well are discussed elsewhere herein.”, further see paragraph 0106).
Regarding claim 5, Tangudu further discloses
The method of claim 1, wherein the operation comprises determining, by the receiver, a geographic location of the receiver ( see paragraph 0140, “.A further decision step 560 determines whether the computed amount of cross correlation is sufficient to indicate that the peak is a cross correlation peak or is uselessly corrupted by cross correlation. If not, the peak is regarded as a valid peak and operations proceed to Signal Detected step 570 to log the peak is valid and utilize it for positioning purposes.”, where “utilizing it for positioning purposes” is tantamount to determining a geographic location of the receiver).
Regarding claim 6, Tangudu further discloses
The method of claim 1, wherein the determining the second measurement comprises calculating a result of an equation comprising the first measurement and a constant value (see paragraph 0136, “A conservative Approach 1 to cross correlation mitigation might operate so that if a low power SV signal is detected with the Doppler shift of its 1.575 GHz carrier at close to a multiple of one kHz (because the periodicity is 1 ms which corresponds to 1/1 ms=1 kHz) away from the carrier Doppler of a high power SV, and if the C/N.sub.o difference between SV1 and SV2 is greater than a static threshold (18 db Hz), the signal is assumed to be a cross correlation peak and rejected. (The expression C/N.sub.o signifies the ratio of Carrier signal power C for the SV to Noise Spectral Density N.sub.o.”, where the first measurements is the C/N.sub.o value and the constant value is the ” C/N.sub.o difference between SV1 and SV2”).
Regarding claim 7, Tangudu further discloses
The method of claim 6, wherein the constant value comprises a first power delta value measured with respect to the first satellite (see paragraph 0136, “A conservative Approach 1 to cross correlation mitigation might operate so that if a low power SV signal is detected with the Doppler shift of its 1.575 GHz carrier at close to a multiple of one kHz (because the periodicity is 1 ms which corresponds to 1/1 ms=1 kHz) away from the carrier Doppler of a high power SV, and if the C/N.sub.o difference between SV1 and SV2 is greater than a static threshold (18 db Hz), the signal is assumed to be a cross correlation peak and rejected. (The expression C/N.sub.o signifies the ratio of Carrier signal power C for the SV to Noise Spectral Density N.sub.o.”, the constant value is the ” C/N.sub.o difference between SV1 and SV2” which is power delta values with respect to SV1).
Regarding claim 10, Tangudu further discloses
The method of claim 1, wherein the determining the second measurement comprises:
selecting the second signal to be a tracked signal (this limitation is indefinite, see 35 U.S.C. 112b section);
performing tracking on the second signal and determining a calibration measurement associated with the second signal (this limitation is indefinite, see 35 U.S.C. 112b section since the second signal cannot be tracked as it is untracked); and
determining the second measurement based on the first measurement of the first signal and based on the calibration measurement (this limitation is indefinite, see 35 U.S.C. 112b section).
Regarding claim 11, Tangudu further discloses
The method of claim 1, wherein the determining the second measurement comprises:
receiving a sample corresponding to the second signal (see Fig. 8 depicting the sampled data); and
determining a location of a peak signal strength of the second signal based on the tracking the first signal, the location being associated with a signal frequency and a signal code phase of the first signal (see paragraph 0136, “A conservative Approach 1 to cross correlation mitigation might operate so that if a low power SV signal is detected with the Doppler shift of its 1.575 GHz carrier at close to a multiple of one kHz (because the periodicity is 1 ms which corresponds to 1/1 ms=1 kHz) away from the carrier Doppler of a high power SV, and if the C/N.sub.o difference between SV1 and SV2 is greater than a static threshold (18 db Hz), the signal is assumed to be a cross correlation peak and rejected. (The expression C/N.sub.o signifies the ratio of Carrier signal power C for the SV to Noise Spectral Density N.sub.o. The Hertz Hz unit represents reciprocal integration period.) Note the use of a single value (18 db Hz down from SV2) for declaring cross correlation peak in this conservative Approach 1. That 18 db can throw away more than half the 38 db dynamic range of the receiver when the Doppler difference is integer kHz.”).
Regarding claim 13, Tangudu further discloses
The method of claim 1, further comprising receiving, by a receiver, a third signal of a second satellite and a fourth signal of the second satellite (see Fig. 1 and 2, where multiple satellites SV3 and SV4 transmits signals that are received by the receiver, further see Figs. 13A and 13B); and either:
selecting, by the receiver, both the third signal and the fourth signal to be tracked signals (see paragraph 0145, “In Scenario 2, four (4) satellite vehicles include a single high-powered SV2 at top 460. Three low powered ones SV1, SV3, and SV4 do not exceed a level 463 that is 21 db down from the SV2 received signal strength. Cross correlation processing is advisable, as taught herein.”); or
tracking the third signal and the fourth signal in a time-sharing fashion (see paragraph 0151, “In FIG. 13B, a detail of Scenario 2 of FIG. 13A shows a hypothetical example of different dynamic satellite-specific thresholds T1, T3, T4 respectively generated for different low power satellite signals SV1, SV3, SV4. Because each of the different low power satellite signals like SV1 have different code phases and Doppler shifts, software in FIG. 11 calls module 400, in general, for cross correlation computation based on a respective distinct code phase difference and Doppler difference of each such low power satellite signal compared to a high power satellite signal SV2. In this way, the processes herein are dynamic both over time and over satellites. In FIG. 13B, each of the peaks SV1 and SV3 exceeds its respective cross correlation threshold in this particular illustration. In general, one or more peaks may be rejected, such as SV4 in FIG. 13B. A stronger peak might be rejected and a weaker peak might be passed. The procedure here is remarkably diverse in operation, and intelligently selective and dynamic.”).
Regarding claims 14 and 20, the same cited section and rationale as claim 1 is applied.
Regarding claim 15, the same cited section and rationale as claim 6 is applied.
Regarding claim 16, the same cited section and rationale as claim 7 is applied.
Regarding claim 17, the same cited section and rationale as claim 10 is applied.
Regarding claim 18, the same cited section and rationale as claim 11 is applied.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
Claim(s) 8 and 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Tangudu et al. (US 20110103432 A1) in view of Acheson et al. (US 20210333412 A1).
Regarding claim 8, Tangudu discloses [Note: what Tangudu fails to disclose is strike-through]
The method of claim 7,
Acheson discloses,
wherein the first power delta value is received from a memory of the receiver, the memory storing the first power delta value and storing a second power delta value measured with respect to a second satellite (see paragraph 0033, “The memory buffer 124 can store cross-correlation values representing cross-correlations between the input signal and the multiple ranging codes time shifted by a time offset value associated with that correlator circuit module 110. The memory buffer 124 can form a closed loop with the adder 122, such that the cross-correlation values stored in the memory buffer 124 are shifted along the memory buffer each processing clock cycle to allow incrementing (by the adder 122) each cross-correlation value with a corresponding multiplication product output by the multiplier 120.”).
It would have been obvious to someone with ordinary skill in the art prior to the
effective filing date of the claimed invention to incorporate the features as disclosed by Acheson into the invention of Tangudu. Both references are considered analogous arts to the claimed invention as they both disclose the detection of cross correlation signals in received satellite data. Tangudu already discloses the features of determining power delta values to identify cross correlation signals. Tangudu fails to disclose the feature of retrieving these values from memory for calibration; however Acheson discloses that these values can be saved to memory and retrieved from memory. The combination would be obvious with a reasonable expectation of success in order to perform calibration and more accurate detection of cross-correlation signals (i.e. spoofing signals).
Regarding claim 9, Tangudu discloses [Note: what Tangudu fails to disclose is strike-through]
The method of claim 7,
Acheson discloses,
wherein the first power delta value is received from a server that is communicatively coupled to the receiver (see paragraph 0033, “The memory buffer 124 can store cross-correlation values representing cross-correlations between the input signal and the multiple ranging codes time shifted by a time offset value associated with that correlator circuit module 110. The memory buffer 124 can form a closed loop with the adder 122, such that the cross-correlation values stored in the memory buffer 124 are shifted along the memory buffer each processing clock cycle to allow incrementing (by the adder 122) each cross-correlation value with a corresponding multiplication product output by the multiplier 120.”).
It would have been obvious to try by one of ordinary skill in the art at the time of the
effective filing date of the claimed invention to yield in invention for claim 9 in light of Tangudu in view of Acheson. Acheson discloses that the cross correlation values can be saved to memory and retrieved from memory. Furthermore, MPEP § 2141 provides that an invention may render a claimed limitation obvious when it would be “obvious to try” to choose from a finite number of identified, predictable solutions, with a reasonable expectation of success. In such an instance it would be obvious to try to save and retrieve the values to a server as data can only be stored in either the memory of the actual device or the memory of a server. The combination would be obvious with a reasonable expectation of success in order to perform calibration and more accurate detection of cross-correlation signals (i.e. spoofing signals).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure:
MARMET (US 20200371247 A1) discloses performing exhaustive 2D correlation search over code phase delay and Doppler shift for one or more GNSS spreading codes, then analyzing the resulting peaks for signs of spoofing [0018], [0045]-[0052]. Instead of relying only on one tracked signal, it searches the entire grid and can identify multiple peaks in a single acquisition [0058]-[0060]. It further reduces false alarms by ignoring peaks that do not persist across successive acquisitions, and by treating closely spaced peaks as multipath rather than spoofing when appropriate [0061]-[0068]. The same analysis framework can also flag jamming and estimate threat details for output to a receiver or user [0030], [0040], [0080]-[0084].
Lennen (US 20140132446 A1) disclose an invention that checks whether a detected peak behaves like a true autocorrelation peak or like a cross-correlation artifact by examining a limited number of nearby chip offsets around the peak. If any nearby value is within a threshold of the main peak, the peak is classified as false. The threshold and number of offsets can be tuned based on signal-to-noise ratio and accumulation time. The method is implemented in a receiver using correlators/matched filters and processor logic to reject invalid satellites.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to NAZRA N. WAHEED whose telephone number is (571)272-6713. The examiner can normally be reached M-F (8 AM - 4:30 PM).
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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.
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/NAZRA NUR WAHEED/Primary Examiner, Art Unit 3648
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