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 .
Response to Amendment
Claims 1-2, 9, and 17 have been amended.
Claims 1-20 are pending.
Applicant's amendments overcome the objection to claim 17.
No New Matter was noticed.
Response to Arguments
Applicant's arguments with respect to amendments to independent claims 1-20 are moot based on the new grounds of rejection as necessitated by amendment. The added limitations are directed to two GNSS signals contemporaneously transmitted from physically separate antennas of a single GNSS satellite offset by a lever arm, and to determining authenticity by comparing a measured inter-signal code-phase relationship to an expected relationship computed from satellite ephemeris, receiver location, and lever-arm geometry. These new limitations necessitate the new combination of references set forth below (substituting Hartman (US 5,557,284) for the previously-applied Gum et al. (US 2023/0288571 A1) reference as the primary reference)
Applicant argues (Remarks, pp. 2–3) that no combination of Gum et al. (‘571), Lier et al. (US 10,749,252), GPS Block III (Wikipedia), Roberts (“Everything the Modern Surveyor Needs to Know about Multi-GNSS,” SEASC 2019), and Marmet (US 2020/0371247 A1) teaches or suggests the amended independent claims, in particular the measured inter-signal code-phase relationship between two signals transmitted from physically separate antennas of a single satellite offset by a lever arm, and the comparison of that measured relationship to an expected relationship computed from ephemeris, receiver location, and lever-arm geometry. The argument is directed to the prior combination and is rendered moot by the present grounds of rejection. As set forth below, Hartman (US 5,557,284) — not previously applied — teaches authenticating satellite positioning signals by comparing a measured inter-signal range difference, derived from the behavior of the pseudo random (ranging) code, against the expected legitimate relationship computed from satellite ephemeris and the known geometry separating the two signal observation points, with detection of spoofing when the measured value departs from the expected value beyond a threshold. GPS Block III and Lier et al. (‘252) supply the structural predicate amended into the claims — a single GPS satellite that contemporaneously transmits two distinct signals from two physically separate, spatially offset antennas (the earth-coverage and spot-beam/RMP antennas) — i.e., the lever arm.
Claim Objections
Claim 2 is objected to because of the following informalities: Claim 2 recites "function of a measured relationship" which is a carryover from the original claim. However, with the current amendment, Claim 1 now introduces "a measured relationship". Claim 2 must now recite "function of the measured relationship". Appropriate correction is required.
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, 7-13, and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Hartman (US 5,557,284) in view of GPS Block III (Wikipedia) and Lier et al. (US 10,749,252).
Regarding Claims 1 and 9, Claim 1 is an independent system claim and Claim 9 is an independent method claim. The body of Claim 9 recites substantively identical functional content to Claim 1, differing only in statutory category. Claims 1 and 9 are therefore grouped, the full element-by-element analysis is presented for Claim 1, and Claim 9 is rejected for the same reasons, as expressly noted below.
Hartman (‘285) teaches: A global navigation satellite system (GNSS) signal authentication system” (Claim 1) / “A global navigation satellite system (GNSS) signal authentication method” (Claim 9): (Title: “Spoofing detection system for a satellite positioning system”; Abstract: “A pair of antennae in combination with a GPS signal receiver system is employed for detecting the reception of satellite information signals from a spoofing signal transmitter as opposed to those satellite information signals transmitted aboard each of the satellite vehicles which form a satellite positioning system”).
Hartman (‘284) teaches: a receive antenna configured to receive GNSS satellite signals (Col. 5, lines 30-44: “antenna 230a is configured to receive satellite information signals from those satellites which form the GPS satellite positioning system and provide an electrical signal 232a indicative of the received signals”).
Hartman (‘284) does not explicitly teach, but GPS Block III teaches: including a first GNSS satellite signal and a second GNSS satellite signal from a single satellite (GPS Block III, M-code section: “Satellites will transmit two distinct signals from two antennas: one for whole Earth coverage, one in a spot beam”; “A side effect of having two antennas is that, for receivers inside the spot beam, the GPS satellite will appear as two GPS signals occupying the same position”). GPS Block III teaches that a single GPS satellite contemporaneously transmits two distinct signals, such that a receiver in the spot-beam region receives a first and a second GNSS satellite signal from the one satellite.
It would have been obvious to a person having ordinary skills in the art (PHOSITA) before the effective filing date of the claimed invention to apply the satellite-signal authentication of Hartman (’284) to a first and a second GNSS satellite signal transmitted from a single satellite as taught by GPS Block III. One would have been motivated to do so because Hartman (’284) authenticates by evaluating the geometry-dependent relationship between two separately observed satellite signals (col. 9), and GPS Block III teaches that a single GPS Block III satellite concurrently provides two such signals to a receiver, expressly noting that the satellite “will appear as two GPS signals occupying the same position” (M-code section), thereby furnishing from one satellite the very pair of signals on which Hartman’s geometry-dependent evaluation operates and obviating any need for two distinct satellites. There is a reasonable expectation of success because GPS Block III confirms that both signals are concurrently present and receivable at a receiver located within the spot-beam coverage region (M-code section), so the two-signal input required by Hartman’s authentication is available from the single satellite. The combination as a whole thus teaches a receive antenna receiving a first and a second GNSS satellite signal from a single satellite.
Hartman (‘284) teaches: a processor configured to compute a digital fingerprint based on a first digital signal and a second digital signal representing the first GNSS satellite signal and the second GNSS satellite signal, respectively, and determine that the first GNSS satellite signal and the second GNSS satellite signal are authentic based on the digital fingerprint (col. 2. Lines 59-66: “a relative range difference processor derives, from the first and second satellite-antenna specific relative range values, information representative of satellite-specific relative range difference values, each related to a satellite-specific pointing angle”; cols. 2-3, lines 66-7: “an analyzing processor is provided for analyzing and/or comparing, the satellite-specific relative range difference values … with a spoofing detection threshold whereby an indication is provided as to whether or not a the GPS signal receiver system is operating on erroneous signals generated by a spoofing signal generator”). The relative range difference value computed by Hartman (‘284)’s range-difference processor is the digital fingerprint computed from the first and second digital signals, and Hartman (‘284)’s analyzing processor, comparing that value against a threshold to indicate whether the signals are genuine or spoofed, determines authenticity based on that fingerprint.
Hartman (‘284) teaches: wherein the first digital signal and the second digital signal each include a ranging code that uniquely identifies a GNSS satellite (Col. 5: “each of the satellites transmits a satellite information signal of the same frequency, but varying pseudo random code. From the pseudo random code, the GPS signal receiver system 240 identifies the satellite vehicles”). Hartman (‘284)’s per-satellite pseudo random code, from which the receiver identifies the particular satellite vehicle, is a ranging code that uniquely identifies the GNSS satellite.
Hartman (‘284) does not explicitly teach, but GPS Block III teaches: that contemporaneously transmitted the first GNSS satellite signal and the second GNSS satellite signal from physically separate antennas of the GNSS satellite (GPS Block III, M-code section: “the M-code is intended to be broadcast from a high-gain directional antenna, in addition to a wide angle (full Earth) antenna”; “Satellites will transmit two distinct signals from two antennas: one for whole Earth coverage, one in a spot beam”). GPS Block III teaches that the two distinct signals are concurrently broadcast from two separate antennas of the one satellite — the wide-angle full-Earth antenna and the high-gain directional spot-beam antenna.
It would have been obvious to a PHOSITA before the effective filing date of the claimed invention to provide that the first and second signals of the combined Hartman (’284)/GPS Block III system are contemporaneously transmitted from physically separate antennas of the satellite as taught by GPS Block III. One would have been motivated to do so because Hartman (’284) requires two signals whose relationship depends on the geometry of their respective sources (cols. 7–9), and GPS Block III teaches that a GPS Block III satellite contemporaneously broadcasts its two distinct signals from two physically separate antennas — a wide-angle full-Earth antenna and a high-gain directional spot-beam antenna (M-code section) — so that the geometry-dependent relationship Hartman exploits arises directly from the separation of the satellite’s two transmitting antennas; using the satellite’s two physically separate antennas as the two signal sources therefore furnishes precisely the geometry-bearing signal pair Hartman’s discriminant requires. There is a reasonable expectation of success because GPS Block III establishes that the dual-antenna broadcast is a designed, operative feature of the satellite and that both signals are concurrently received (M-code section), so the contemporaneously transmitted dual-antenna signals are reliably available to the combined system. The combination as a whole thus teaches the ranging-code-bearing first and second signals contemporaneously transmitted from physically separate antennas of the GNSS satellite.
Hartman (‘284) does not explicitly teach, but Lier et al. (‘252) teaches: the physically separate antennas being spatially separated or otherwise physically offset from each other by a lever arm (Lier et al. (‘252), Abstract: “The first antenna element is located at the center of the antenna array and is surrounded by the second antenna elements”; col. 4, lines 47-67: “The EC antennas 110 … are mounted on a side (e.g., an earth facing side) of the GPS spacecraft 100 … The RMP reflector dish antenna 130 is mounted (shown stowed) on a front face of the GPS spacecraft 100”; “The EC antennas 110, the MEC antennas 120, and the RMP reflector dish antenna 130 can have separate phase and group delay centers”). The recited “spatially separated or otherwise physically offset” is an alternative limitation, and Lier et al. (’252) teaches at least the physically-offset alternative
It would have been obvious to a PHOSITA before the effective filing date of the claimed invention to implement the physically separate antennas of the combined Hartman (’284)/GPS Block III system as the spatially offset earth-coverage and RMP antennas taught by Lier et al. (’252). One would have been motivated to do so because Lier et al. (’252) teaches the concrete construction of the GPS Block III earth-coverage and spot-beam functions as distinct EC and RMP antennas mounted at separate physical locations on the spacecraft — the EC antennas on the earth-facing side and the RMP reflector dish on the front face — with separate phase centers (Abstract; col. 4), thereby realizing the two physically separate antennas of GPS Block III as structures separated by a definite spatial offset (a lever arm), which is the very geometric separation Hartman’s relationship depends upon. There is a reasonable expectation of success because Lier et al. (’252) demonstrates that this offset antenna payload is a realized, operative GPS Block III configuration with characterized phase centers (col. 4), so the physically offset antenna pair is an established structure that supplies the lever-arm separation to the combined system. The combination as a whole thus teaches the physically separate antennas being physically offset from each other by a lever arm.
Hartman (‘284) teaches: the digital fingerprint being a function of a measured relationship between a code phase of the first GNSS satellite signal and a code phase of the second GNSS satellite signal (Hartman (‘284), Abstract: “The pointing angle and/or alternatively the range difference may be observed by monitoring the behavior of the pseudo random code associated with the carrier of the satellite information signal”; col. 1, lines 27-51: “detects a pseudo random code contained in a given GPS satellite information signal carrier and derives therefrom the ‘elapsed time’ or time delay between the transmission of the signal and its reception … the GPS signal receiver system can derive the range”; col. 7–8: the “range difference “D””). The inter-signal range difference, observed by monitoring the behavior of the pseudo random code (the code phase) of each signal, is a function of a measured relationship between the code phases of the two signals.
Hartman (‘284) teaches: and determine that the first GNSS satellite signal and the second GNSS satellite signal are authentic based on the digital fingerprint by determining that the measured relationship is within an acceptable tolerance of an expected relationship between the first GNSS satellite signal and the second GNSS satellite signal for an orbital location of the GNSS satellite with respect to a location of the receive antenna (Col. 9, lines 53-61: “the transmitter-antenna-specific pointing angle will be sufficiently different than the expected legitimate GPS satellite information signal characteristics and discernible so as to be used as a discriminant for a detector for the presence of a satellite information signal transmitted from a spoofing signal transmitter”; col. 10, lines 5-15: “Comparator 360 compares each value of the set of … difference values … with a spoof detection threshold value “SDT””). Authenticity is determined by comparing the measured inter-signal relationship to the expected legitimate value for the genuine satellite-to-antenna geometry, the spoof-detection threshold defining the acceptable tolerance.
Hartman (‘284) teaches: the expected relationship between the first GNSS satellite signal and the second GNSS satellite signal being based on satellite ephemeris and the location of the receive antenna relative to the orbital location of the GNSS satellite (Col. 2, lines 5-15: “each satellite information signal also contains precise ephemeris and coarse almanac data which both describe the corresponding satellite’s orbital trajectory … the GPS signal receiver system may derive the geocentric position of the satellite at selected moments of time”). The expected inter-signal relationship is computed from the satellite’s ephemeris-derived orbital position and the receiving antenna’s location relative thereto.
Hartman (‘284) does not explicitly teach, but Lier et al. (‘252) teaches: and lever arm geometry between the physically separate antennas (Cols. 3–4: “Orienting all of the three L-band antennas above the CG results in the best possible PNT accuracy by minimizing L-band phase center movement of the EC and RMP signals during a yaw turn and relative movement caused by the satellite traversing a user on the surface of the earth as opposed to an L-band antenna that is offset from the CG and … broadcast messages to users to account for the offset”).
It would have been obvious to a PHOSITA before the effective filing date of the claimed invention to compute the expected inter-signal relationship of the combined Hartman (’284)/GPS Block III/Lier et al. (’252) system using the lever-arm geometry between the physically separate antennas as taught by Lier et al. (’252). One would have been motivated to do so because Hartman’s expected-value computation requires the geometry separating the two signal sources (col. 7–8), and Lier et al. (’252) teaches that the EC and RMP antennas occupy a fixed offset whose projected geometry varies predictably with satellite yaw and orbital traversal and which is conventionally characterized and “broadcast [] to users to account for the offset” (col. 3–4); using this characterized lever-arm geometry to compute the expected inter-signal relationship therefore supplies the satellite-side geometric input Hartman requires for any given orbital location. There is a reasonable expectation of success because Lier et al. (’252) demonstrates that the EC/RMP offset and its orbit-dependent geometry are known, characterized, and conventionally transmitted to and accounted for by receivers (col. 3–4), so the lever-arm contribution to the expected relationship is a determinable quantity readily computed and compared in the manner taught by Hartman (’284). The combination as a whole thus teaches the expected relationship being based on satellite ephemeris, the location of the receive antenna relative to the orbital location of the satellite, and lever-arm geometry between the physically separate antennas.
Regarding Claim 9, the claim is substantially the same as claim 1 and thus, the same cited sections and rationale as corresponding apparatus claim 1 is applied.
Regarding Claim 2, Hartman (‘284) in view of GPS Block III and Lier et al. (‘252) teaches the system of Claim 1.
Hartman (‘284) teaches: wherein the digital fingerprint is a function of a measured relationship between a code phase of the first GNSS satellite signal and a code phase of the second GNSS satellite signal, wherein the measured relationship represents a geometric range difference between the first GNSS satellite signal and the second GNSS satellite signal, the geometric range difference being realized as a code phase offset of the first GNSS satellite signal and the second GNSS satellite signal (Abstract: “the range difference may be observed by monitoring the behavior of the pseudo random code associated with the carrier of the satellite information signal”; col. 7–8, lines 60-65: “the difference between the magnitude of the line-of-sight vectors … herein referred to as the range difference “D””). The range difference D is a geometric difference between the two signal ranges, observed as an offset in the behavior of the pseudo random code (the code phase) between the two signals — i.e., the geometric range difference realized as a code phase offset.
Regarding Claim 3, Hartman (‘284) in view of GPS Block III and Lier et al. (‘252) teaches the system of Claim 2.
Hartman (‘284) teaches: wherein the digital fingerprint is determined to be authentic if the measured relationship is the same as an expected relationship between the first GNSS satellite signal and the second GNSS satellite signal for an orbital location of the GNSS satellite with respect to a location of the receive antenna (Col. 9, lines 53-61: “the transmitter-antenna-specific pointing angle will be sufficiently different than the expected legitimate GPS satellite information signal characteristics”; col. 10, lines 5-15: “Comparator 360 compares each value … with a spoof detection threshold value “SDT””). The signals are deemed genuine when the measured inter-signal relationship is not discernibly different from the expected legitimate relationship for the genuine satellite-to-antenna geometry.
Regarding Claim 4, Hartman (‘284) in view of GPS Block III and Lier et al. (‘252) teaches the system of Claim 3.
Hartman (‘284) teaches: wherein the expected relationship between the first GNSS satellite signal and the second GNSS satellite signal is based on satellite ephemeris and the location of the receive antenna relative to the orbital location of the GNSS satellite (Col. 2, lines 5-15: “each satellite information signal also contains precise ephemeris and coarse almanac data which both describe the corresponding satellite’s orbital trajectory … the GPS signal receiver system may derive the geocentric position of the satellite”). The expected inter-signal relationship is derived from the ephemeris-derived orbital position and the receiving antenna’s location relative thereto.
Regarding Claim 5, Hartman (‘284) in view of GPS Block III and Lier et al. (‘252) teaches the system of Claim 3.
Hartman (‘284) teaches: wherein the measured relationship and the expected relationship each represent a range difference between the first GNSS satellite signal and the second GNSS satellite signal, the range difference being scaled by a cosine of an arc angle between the location of the receive antenna and a point nadir of the GNSS satellite with respect to the location of the receive antenna (Col. 7–8: “a line projected from the intersection of reference line 236 and vector LOS[b] perpendicular to vector LOS[a] defines the mathematical relationship for the difference between the magnitude of the line-of-sight vectors … herein referred to as the range difference “D””). The inter-signal range difference D is the projection — the cosine — of the fixed separation between the two observation points onto the line-of-sight direction, that direction being fixed by the receiver’s location relative to the satellite’s line-of-sight (nadir) direction; the measured and expected range differences therefore each represent the geometric separation scaled by the cosine of the arc angle between the receive-antenna location and the satellite’s point nadir.
Regarding Claim 7, Hartman (‘284) in view of GPS Block III and Lier et al. (‘252) teaches the system of Claim 1.
Hartman (‘284) does not explicitly teach, but GPS Block III teaches: wherein the first GNSS satellite signal is an Earth coverage M-code signal (GPS Block III, M-code section: “the M-code is intended to be broadcast from a high-gain directional antenna, in addition to a wide angle (full Earth) antenna”; “one for whole Earth coverage”).
It would have been obvious to a PHOSITA before the effective filing date of the claimed invention to identify the first signal of the combined system as the Earth coverage M-code signal taught by GPS Block III. One would have been motivated to do so because GPS Block III teaches that the whole-Earth-coverage signal broadcast from the wide-angle antenna is the M-code (M-code section), which is one of the two physically-separate-antenna signals already relied upon in the combined Claim 1 rejection, so identifying the first signal as the EC M-code signal merely designates the very signal GPS Block III describes; the motivation and reasonable expectation of success set forth for Claim 1 regarding the Hartman (’284)/GPS Block III combination are expressly incorporated. There is a reasonable expectation of success because GPS Block III establishes the EC M-code as an operative, concurrently broadcast signal of the satellite (M-code section). The combination as a whole thus teaches the first GNSS satellite signal is an Earth coverage M-code signal.
Hartman (‘284) does not explicitly teach, but Lier et al. (‘252) teaches: and the second GNSS satellite signal is an RMP signal (Col. 1, lines 21-48: “three different L-band antennas including earth coverage (EC), military earth coverage (MEC) and regional military protection (RMP) antennas to broadcast the full set of GPS L-band signals”; col. 4, lines 47-67: “an RMP reflector dish antenna 130”).
It would have been obvious to a PHOSITA before the effective filing date of the claimed invention to identify the second signal of the combined system as the RMP signal taught by Lier et al. (’252). One would have been motivated to do so because Lier et al. (’252) teaches that the regional military protection (RMP) antenna broadcasts a distinct L-band signal (col. 1; col. 4), which is the second of the two physically-separate-antenna signals already relied upon in the combined Claim 1 rejection, so identifying the second signal as the RMP signal merely designates the signal Lier et al. (’252) describes; the motivation and reasonable expectation of success set forth for Claim 1 regarding the addition of Lier et al. (’252) are expressly incorporated. There is a reasonable expectation of success because Lier et al. (’252) establishes the RMP signal as broadcast from the realized RMP reflector dish antenna of the spacecraft (col. 4). The combination as a whole thus teaches the second GNSS satellite signal is an RMP signal.
Regarding Claim 8, Hartman (‘284) in view of GPS Block III and Lier et al. (‘252) teaches the system of Claim 1.
Hartman (‘284) teaches: further comprising a radio frequency (RF) receiver circuit coupled between the receive antenna and the processor, the RF receiver circuit configured to convert the first GNSS satellite signal and the second GNSS satellite signal into the first digital signal and the second digital signal, respectively (Col. 5, lines 30-44: “antenna 230a … provide[s] an electrical signal 232a … [as] an input to GPS signal receiver system 240a”; col. 6, lines 20-32: the receiver system provides the resulting information “preferably in digital form for processing by subsequent signal or data processors”). The GPS signal receiver system, coupled between the antenna and the downstream range-difference/analyzing processors and converting the received satellite signals into digital form, is the recited RF receiver circuit.
Regarding Claims 10–13, Claims 10–13 depend (directly or indirectly) from independent method Claim 9 and recite added limitations corresponding, respectively, to the added limitations of system Claims 2–5 analyzed above. Each added step is required to be performed under the broadest reasonable interpretation, as none is conditioned upon a precedent contingency. Claims 10–13 are rejected under the same combination of Hartman (‘284), GPS Block III, and Lier et al. (‘252) for the reasons set forth for the corresponding system claims, as follows.
Regarding Claim 10, Hartman (‘284) teaches: wherein the digital fingerprint is a function of a first measured relationship between the first digital signal and the second digital signal, the first measured relationship being representative of a second measured relationship between a code phase of the first GNSS satellite signal and a code phase of the second GNSS satellite signal (Abstract and col. 7–8, as cited for Claim 2: the inter-signal range difference observed through the behavior of the pseudo random code is a measured relationship between the digital signals representative of the relationship between the code phases of the two satellite signals).
Regarding Claim 11, Hartman (‘284) teaches: wherein the digital fingerprint is determined to be authentic if the measured relationship is the same as an expected relationship between the first digital signal and the second digital signal for an orbital location of the GNSS satellite with respect to a location of a receive antenna (Cols. 9–10, as cited for Claim 3).
Regarding Claim 12, Hartman (‘284) teaches: wherein the expected relationship between the first digital signal and the second digital signal is based on satellite ephemeris and the location of the receive antenna relative to the orbital location of the GNSS satellite (Col. 2, as cited for Claim 4).
Regarding Claim 13, Hartman (‘284) teaches: wherein the measured relationship and the expected relationship each represent a range difference between the first digital signal and the second digital signal, the range difference being scaled by a cosine of an arc angle between the location of the receive antenna and a point nadir of the GNSS satellite with respect to the location of the receive antenna (Col. 7–8, as cited for Claim 5).
Regarding Claim 15, Hartman (‘284) in view of GPS Block III and Lier et al. (‘252) teaches the method of Claim 9. Claim 15 recites the same added limitation as system Claim 7.
Hartman (‘284) does not explicitly teach, but GPS Block III teaches wherein the first GNSS satellite signal is an Earth coverage M-code signal (GPS Block III, M-code section: “one for whole Earth coverage”).
It would have been obvious to a PHOSITA before the effective filing date of the claimed invention to identify the first signal of the combined method as the Earth coverage M-code signal taught by GPS Block III, for the same reasons set forth for Claim 7, which are expressly incorporated: GPS Block III teaches the whole-Earth-coverage M-code as one of the two physically-separate-antenna signals already relied upon (M-code section). There is a reasonable expectation of success because GPS Block III establishes the EC M-code as an operative, concurrently broadcast signal (M-code section). The combination as a whole thus teaches the first GNSS satellite signal is an Earth coverage M-code signal.
Hartman (‘284) does not explicitly teach, but Lier et al. (‘252) teaches and the second GNSS satellite signal is an RMP signal (Col. 1, lines 21-48 and col. 4, lines 47-67: “regional military protection (RMP) … antennas”; “an RMP reflector dish antenna 130”).
It would have been obvious to a PHOSITA before the effective filing date of the claimed invention to identify the second signal of the combined method as the RMP signal taught by Lier et al. (’252), for the same reasons set forth for Claim 7, which are expressly incorporated: Lier et al. (’252) teaches the RMP antenna broadcasts the distinct second signal already relied upon (col. 1; col. 4). There is a reasonable expectation of success because Lier et al. (’252) establishes the RMP signal as broadcast from the realized RMP reflector dish antenna (col. 4). The combination as a whole thus teaches the second GNSS satellite signal is an RMP signal.
Claims 6 and 14 are rejected under 35 U.S.C. 103 as being unpatentable over Hartman (US 5,557,284) in view of GPS Block III (Wikipedia) and Lier et al. (US 10,749,252) as applied to Claims 3 and 11 above, and further in view of Roberts (“Everything the Modern Surveyor Needs to Know about Multi-GNSS,” SEASC 2019).
Regarding Claims 6 and 14, Claim 6 depends from Claim 3 and Claim 14 depends from Claim 11; each recites the same added limitation. They are grouped, the analysis is presented for Claim 6, and Claim 14 is rejected for the same reasons.
Regarding Claim 3, Hartman (‘284) in view of GPS Block III and Lier et al. (‘252) teaches the system of Claim 3.
Hartman (‘284), GPS Block III, and Lier et al. (‘252) do not explicitly teach, but Roberts teaches: wherein the function of the measured relationship between the first GNSS satellite signal and the second GNSS satellite signal includes a differential code bias that is unique to the GNSS satellite (Roberts, p. 12: “Differential code biases (DCB) are differences in the signal travel time for two signals of a given GNSS as a consequence of hardware-dependent group delays in the satellites’ transmission and receivers’ reception instrumentation”; p. 12: “both of these inter-system biases have been found to be relatively stable (within noise limits) and can be calibrated as known quantities”). Roberts teaches that the differential code bias — a difference in signal travel time between two signals of a given GNSS arising from hardware-dependent group delays in the satellite’s transmission instrumentation — is a satellite-specific, stable, and calibratable quantity, i.e., a differential code bias unique to the GNSS satellite that forms part of the inter-signal travel-time (code-phase) relationship.
It would have been obvious to a PHOSITA before the effective filing date of the claimed invention to include the satellite-unique differential code bias taught by Roberts in the function of the measured inter-signal relationship of the combined Hartman (’284)/GPS Block III/Lier et al. (’252) system. One would have been motivated to do so because Roberts teaches that the differential code bias is a hardware-dependent group-delay difference between two signals of a given satellite that directly contributes to the measured inter-signal travel-time (and hence code-phase) relationship and that, being stable and calibratable as a known quantity (p. 12), can be incorporated as a known component of the expected inter-signal relationship; accounting for the satellite-unique differential code bias in the combined system’s comparison thereby improves the accuracy with which the measured relationship is matched to the expected relationship and sharpens the spoofing discriminant of Hartman (’284), since a spoofer would additionally have to reproduce the genuine satellite’s unique differential code bias. There is a reasonable expectation of success because Roberts demonstrates that the differential code bias is a measurable, stable, and calibratable quantity applied as a known value in GNSS code-phase processing (p. 12), so its inclusion in the inter-signal function is a predictable use of a known parameter. The combination as a whole thus teaches that the function of the measured relationship includes a differential code bias that is unique to the GNSS satellite.
Regarding Claim 14, the claim is substantially the same as claim 6 and thus, the same cited sections and rationale as corresponding apparatus claim 6 is applied.
Claims 16, 17, 18, and 19 are rejected under 35 U.S.C. 103 as being unpatentable over Hartman (US 5,557,284) in view of GPS Block III (Wikipedia) and Lier et al. (US 10,749,252), and further in view of Marmet (US 2020/0371247 A1).
Regarding Claim 16, Hartman (‘284) in view of GPS Block III and Lier et al. (‘252) teaches the method of Claim 9. Claim 16 positively recites two further method steps; neither is framed as conditional upon a precedent contingency, and both are therefore required to be performed under the broadest reasonable interpretation.
Hartman (‘284) teaches: determining, by the one or more processors, that the first digital signal and the second digital signal are not authentic based on the digital fingerprint (col. 10, 5-15: “Comparator 360 compares each value of the set of … difference values D(t) with a spoof detection threshold value ‘SDT’ for generating an alarm based on a single transmitter-specific range difference D(t) exceeding a specified spoofing detection threshold”). The signals are determined not authentic when the measured inter-signal relationship exceeds the spoofing detection threshold.
Hartman (‘284) does not explicitly teach, but Marmet (‘247) teaches: and initiating one or more remedial actions ([0057]: “Spoofing alarms may be recorded for later analysis or sent in real-time to a navigation system”; [0060]: “This output may trigger a specific action, as for instance displaying a sonic or visual alarm to notify a user that the position computed by the GNSS receiver might be spoofed”). Marmet (‘247) teaches initiating remedial actions upon spoofing detection, including raising a visual or audible alarm and transmitting the spoofing determination to the navigation system.
It would have been obvious to a PHOSITA before the effective filing date of the claimed invention to initiate the remedial actions taught by Marmet (’247) upon the not-authentic determination of the combined Hartman (’284)/GPS Block III/Lier et al. (’252) system. One would have been motivated to do so because Hartman (’284) produces a spoofing indication/alarm upon detecting non-genuine signals but is directed to the detection itself, whereas Marmet (’247) teaches that, once spoofing is detected, the detection result should trigger a remedial response — alerting the user by a visual or audible alarm and/or conveying the result to the navigation system ([0057], [0060]) — so that the receiver does not rely on spoofed position/timing data; incorporating Marmet’s remedial response completes the anti-spoofing function by acting upon Hartman’s detection. There is a reasonable expectation of success because Marmet (’247) demonstrates that conveying a spoofing determination to a user interface or navigation system to trigger a remedial response is a conventional and operative consequence of GNSS spoofing detection ([0057], [0060]). The combination as a whole thus teaches determining that the signals are not authentic and initiating one or more remedial actions.
Regarding Claim 17, Claim 17 is an independent system claim reciting a GNSS receive antenna, a processor, a display, and a circuit, whose authentication functions correspond substantively to those of Claim 1, and which further recites a display and a circuit. As a system claim, the recited functional capabilities (including the display being caused to provide an indication) are not disregarded; the prior art must teach the corresponding structure configured to perform the function, and it does, as set forth below.
Hartman (‘284) teaches: a global navigation satellite system (GNSS) receive antenna; a processor; (Col. 5, lines 30-44: “antenna 230a is configured to receive satellite information signals”; col. 2: the “relative range difference processor” and “analyzing processor”).
Hartman (‘284) does not explicitly teach, but Marmet teaches: a display operatively coupled to the processor ([0056]: “the information about spoofing 203 may be transmitted to a screen or a computer for display”). Marmet teaches a display coupled to the spoofing-determination processor for presenting the spoofing/authentication result.
It would have been obvious to a PHOSITA before the effective filing date of the claimed invention to provide the combined Hartman (’284)/GPS Block III/Lier et al. (’252) system with a display operatively coupled to the processor as taught by Marmet (’247). One would have been motivated to do so because Hartman (’284) produces an authentication determination but is directed to the detection processing, whereas Marmet (’247) teaches coupling a display to the spoofing-determination processor to present the determination, transmitting the spoofing information “to a screen or a computer for display” ([0056]); providing such a display renders the combined system’s determination observable to a user. There is a reasonable expectation of success because Marmet (’247) demonstrates that coupling a display to a GNSS spoofing-determination processor is operative ([0056]). The combination as a whole thus teaches a display operatively coupled to the processor.
Hartman (‘284) teaches: a circuit configured to generate a first digital signal and a second digital signal from the receive antenna to the processor (Col. 5–6: the GPS signal receiver system between the antenna and the processors provides the signal information “preferably in digital form for processing by subsequent signal or data processors”). Hartman (‘284)’s receiver system is the recited circuit generating the first and second digital signals from the receive antenna to the processor.
The limitations directed to the first digital signal and the second digital signal each representing a first GNSS satellite signal and a second GNSS satellite signal, respectively, received from a GNSS satellite and including a ranging code that uniquely identifies the GNSS satellite, the first GNSS satellite signal and the second GNSS satellite signal contemporaneously transmitted from physically separate antennas onboard the GNSS satellite, the physically separate antennas being spatially separated or otherwise physically offset from each other by a lever arm, and the processor being configured to determine that the first GNSS satellite signal and the second GNSS satellite signal are authentic or not authentic … by computing a digital fingerprint as a function of a measured relationship between a code phase of the first digital signal and a code phase of the second digital signal and determining that the measured relationship is within an acceptable tolerance of an expected relationship … the expected relationship … being based on satellite ephemeris and the location of the receive antenna relative to the orbital location of the GNSS satellite and lever arm geometry between the physically separate antennas, are taught by Hartman (’284) in view of GPS Block III and Lier et al. (’252) for the reasons set forth for Claim 1 above — including, for each limitation supplied by GPS Block III or by Lier et al. (’252), the “primary does not teach” predicate, the motivation to combine, and the reasonable-expectation-of-success findings — all of which are expressly incorporated herein. The recited “authentic or not authentic” is an alternative; the prior art need teach only one alternative, and Hartman (’284) teaches determining that signals are not authentic by the threshold comparison of the measured-to-expected inter-signal relationship (col. 10).
Hartman (‘284) does not explicitly teach, but Marmet teaches: cause the display to provide an indication that the first GNSS satellite signal and the second GNSS satellite signal are authentic or not authentic ([0060]: “This output may trigger a specific action, as for instance displaying a sonic or visual alarm to notify a user that the position computed by the GNSS receiver might be spoofed”; [0056]: “transmitted to a screen or a computer for display”). The recited “authentic or not authentic” is an alternative, and Marmet (’247) teaches at least the not-authentic indication (a visual alarm upon spoofing).
It would have been obvious to a PHOSITA before the effective filing date of the claimed invention to cause the display of the combined system to provide an indication that the signals are authentic or not authentic as taught by Marmet (’247). One would have been motivated to do so because Marmet (’247) teaches that the spoofing/authentication determination is output to the display to notify the user — e.g., “displaying a sonic or visual alarm to notify a user that the position computed by the GNSS receiver might be spoofed” ([0060]) — so that the user can recognize whether the signals are trustworthy and act accordingly; causing the display to present the authentication determination of Hartman (’284) thereby renders that determination actionable to the user. There is a reasonable expectation of success because Marmet (’247) demonstrates that presenting a GNSS spoofing/authentication determination on a display to alert the user is a conventional and operative output of a spoofing-detection system ([0056], [0060]), requiring only routine coupling of the existing display to the existing determination processor. The combination as a whole thus teaches causing the display to provide an indication that the first and second GNSS satellite signals are authentic or not authentic.
Regarding Claim 18, Hartman (’284) in view of GPS Block III and Lier et al. (’252) teaches the system of Claim 17.
Hartman (‘284) teaches: wherein the processor is further configured to compute a digital fingerprint as a function of a measured relationship between a code phase of the first digital signal and a code phase of the second digital signal, and the first digital signal and the second digital signal are determined to be authentic if the digital fingerprint is the same as an expected relationship between the first digital signal and the second digital signal for an orbital location of the GNSS satellite with respect to a location of the receive antenna (Abstract and cols. 7–10, as cited for Claims 2 and 3: the inter-signal range difference derived from the pseudo random code is the digital fingerprint, and the signals are deemed genuine when that measured relationship matches the expected legitimate relationship).
Regarding Claim 19, Hartman (‘284) teaches: wherein the expected relationship between the first digital signal and the second digital signal is based on satellite ephemeris and the location of the receive antenna relative to the orbital location of the GNSS satellite (Col. 2, as cited for Claim 4).
Claim 20 is rejected under 35 U.S.C. 103 as being unpatentable over Hartman (US 5,557,284) in view of GPS Block III (Wikipedia), Lier et al. (US 10,749,252), and Marmet (US 2020/0371247 A1) as applied to Claim 19 above, and further in view of Roberts (“Everything the Modern Surveyor Needs to Know about Multi-GNSS,” SEASC 2019).
Regarding Claim 20, Hartman (‘284) in view of GPS Block III, Lier et al. (‘252), and Marmet teaches the system of Claim 19. Claim 20 recites two added requirements: a cosine-scaled range difference and a satellite-unique differential code bias.
Hartman (‘284) teaches: wherein the digital fingerprint and the expected relationship each represent a range difference between the first digital signal and the second digital signal, the range difference being scaled by a cosine of an arc angle between the location of the receive antenna and a point nadir of the GNSS satellite with respect to the location of the receive antenna (Col. 7–8, as cited for Claim 5: the range difference D is the projection — the cosine — of the fixed inter-signal separation onto the line-of-sight direction fixed by the receiver’s location relative to the satellite’s nadir direction).
Hartman (‘284), GPS Block III, Lier et al. (‘252), and Marmet do not explicitly teach, but Roberts teaches: and wherein the function of the measured relationship between the first digital signal and the second digital signal includes a differential code bias that is unique to the GNSS satellite (Roberts, p. 12: “Differential code biases (DCB) are differences in the signal travel time for two signals of a given GNSS as a consequence of hardware-dependent group delays in the satellites’ transmission and receivers’ reception instrumentation”, and “can be calibrated as known quantities”). The satellite-specific, calibratable differential code bias taught by Roberts is a differential code bias unique to the GNSS satellite, included in the function of the measured inter-signal relationship.
It would have been obvious to a PHOSITA before the effective filing date of the claimed invention to include the satellite-unique differential code bias of Roberts in the function of the measured inter-signal relationship of the combined Hartman (’284)/GPS Block III/Lier et al. (’252)/Marmet (’247) system. One would have been motivated to do so because Roberts teaches that the differential code bias is a hardware-dependent, satellite-unique, stable, and calibratable contribution to the inter-signal travel-time (code-phase) relationship (p. 12), so its inclusion as a known component of the inter-signal function improves the accuracy of the measured-to-expected comparison and sharpens the spoofing discriminant, since a spoofer would additionally have to reproduce the genuine satellite’s unique differential code bias. There is a reasonable expectation of success because Roberts demonstrates that the differential code bias is a measurable, stable, calibratable quantity applied as a known value in GNSS code-phase processing (p. 12). The combination as a whole thus teaches that the function of the measured relationship includes a differential code bias that is unique to the GNSS satellite.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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 REMASH R GUYAH whose telephone number is (571)270-0115. The examiner can normally be reached M-F 7:30-4:30.
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/REMASH R GUYAH/Examiner, Art Unit 3648
/RESHA DESAI/Supervisory Patent Examiner, Art Unit 3648
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