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 amendments filed 5/05/2026 have been entered. Claims 1-13 are pending.
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 5/05/2026 has been entered.
Response to Arguments
Applicant’s arguments, see ’35 U.S.C. 112 Rejection’, filed 5/05/2026, with respect to claims 1 and 13 have been fully considered. The amendment to claim 1 clarifies that the RF signals are discrete in time and the Examiner found in the disclosure that the satellite sends out pulses, therefore the 112a rejection of claim 1 from the first office action is withdrawn. However, the amendment creates more 112 issues which are discussed below. Additionally, claim 13 does not appear to have been changed.
Applicant's arguments see ‘Distinction Over Conventional Doppler-Based LEO Positioning Systems’ filed 5/05/2026 have been fully considered but they are not persuasive. The Examiner respectfully disagrees. As discussed in the 112 rejection below, the Examiner does not see the support for “signal agnostic”. There is no mention of an agnostic signal in the specification nor the exclusion of, for example, modulating or demodulating signals. The Examiner sees the use of Doppler signals, but nothing that states that the method does not use, again for example, modulation. The Examiner makes this distinction because, unless it is explicitly stated, when a disclosure states the use of Doppler measurements the reader would have to assume on whether modulation is included, excluded, or if it has the option to choose. For the purpose of proper examination of the current claims the Examiner is interpreting the current claims as “A method for determining position..."
As such, claim 1 does not explicitly eliminate Phased Locked Loops nor per-satellite association, it does not mention unlabeled spectral energy, and it does not exclude the use of structured signals, decoding, timing and burst structure. The Examiner does not interpret claim 1 as intrinsically having these features as they are not mentioned and other satellite systems also use Doppler signals.
Applicant's arguments see ‘Prior Art Relies on Explicit Pseudorange-Rate Measurements’ filed 5/05/2026 have been fully considered but they are not persuasive. The Examiner respectfully disagrees. Similar to above, claim 1 does not mention or exclude phase-locked loops or pseudorange-rate measurements, and it does not mention eliminating the intermediate transformation. The fundamentally different measurement model is not expressed in the claim.
Applicant's arguments see ‘Prior Art Requires Per-Satellite Tracking and Association’ filed 5/05/2026 have been fully considered but they are not persuasive. The Examiner respectfully disagrees. Similar to above, claim 1 does not mention or exclude continuous tracking loops or pre-association signals to a satellite, and it does not mention timestamps without assigning them to specific satellites. These features are not expressed in the claim.
Applicant's arguments see ‘Prior Art Uses Sequential EKF-Based Estimation’ filed 5/05/2026 have been fully considered but they are not persuasive. The Examiner respectfully disagrees. Similar to above, claim 1 does not mention or exclude known correspondence measurements, and it does not mention global batch optimization nor simultaneous measurement association and position estimation.
Applicant's arguments see ‘The Combination of Features is Neither Disclosed nor Suggested’ filed 5/05/2026 have been fully considered but they are not persuasive. The Examiner respectfully disagrees. Similar to above, claim 1 does not explicitly claim any of the limitations from a-c.
Applicant's arguments see ‘Technical Advantages and Non-Obviousness’ filed 5/05/2026 have been fully considered but they are not persuasive. The Examiner respectfully disagrees. Similar to above, claim 1 does not explicitly claim any of the limitations from a-d, and that it would be improper to assume that the claim in its current state, possesses all of these features.
Applicant's arguments see ‘Response to Prior Art – Distinction Over Doppler Positioning Methods Based Upon Iridium Communications Type Signals’ for sections 1.) and 2.) filed 5/05/2026 have been fully considered but they are not persuasive. The Examiner respectfully disagrees. Similar to above, claim 1 does not explicitly claim or exclude signal structure awareness.
Applicant's arguments see ‘Prior Art Relies on Structured Measurement Extraction and Conventional Estimation’ filed 5/05/2026 have been fully considered but they are not persuasive. The Examiner respectfully disagrees. Claim 1 does not contain any of the details that are stated as being different from the prior art i.e., continuously observing doppler shifts using FFT/Frequency Masked Trigger processing etc.
Applicant's arguments see ‘The Claimed Combination is Neither Disclosed nor Suggested’ filed 5/05/2026 have been fully considered but they are not persuasive. The Examiner respectfully disagrees. Claim 1 does not claim the limitations a-d. As mentioned above ‘signal-agnostic’ does not appear to have support in the specification and the other limitations are not mentioned in the claim.
Applicant's arguments see ‘5. Technical Advantages and Non-Obviousness’ filed 5/05/2026 have been fully considered but they are not persuasive. The Examiner respectfully disagrees. Similar to above, claim 1 does not explicitly claim any of the advantages, and that it would be improper to assume that the claim in its current state, possesses all of these features, as Doppler measurements are not exclusive to this method.
The Examiner cannot agree with the conclusion that the claim is currently patentable. However, the amended claim does include discrete time transmissions from the satellite. Because of this amendment the rejection of claims 1 and 7 are withdrawn but there is another rejection in view of Zhodzishsky (US 6313789 B1)
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 1 and 7 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention. Claim 1 discloses a “signal agnostic” feature that is not mentioned in the specification. There does not appear to be any mention of using, for example, only a Doppler signal or omitting modulation and demodulation. Additionally, in claim 1 there is mention of “intermittent” in time transmissions of a satellite but ‘intermittent’ is not mentioned in the disclosure. The Examiner saw the discussion of the satellite having a pulsed signal, which the Examiner perceived as support for the ‘discrete in time’, but the Examiner does not see, for example, any mention of random or sporadic signals. Claim 1 shall be read as ‘A method for determining positioning, navigation and timing solutions for a ground-based device comprising the steps of: receiving a RF signal at the ground-based device corresponding to a plurality of discrete in time RF transmissions…”
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.
Claims 1-3, 5-13 are rejected under 35 U.S.C. 103 as being unpatentable over Khalife Joe J et al: "Receiver Design for Doppler Positioning with Leo Satellites", ICASSP 2019 - 2019 IEEE International Conference On Acoustics, Speech and Signal Processing (ICASSP), IEEE, 12 May 2019 (2019-05-12), pages 5506-5510, XP033565135, DOI: 10.1109/ICASSP.2019.8682554 in view of Zhodzishsky (US 6313789 B1).
Regarding claim 1, Khalife discloses
A method for determining positioning, navigation and timing solutions for a ground-based device (Page 5506, Introduction, paragraph 3, lines 3-7, "1) design specialized receivers that can extract navigation observables from these signals, 2) develop navigation frameworks that can account for the unknown nature of the LEO satellite SOP states (namely clock bias, drift, and/or position and velocity), and 3) characterize their error budgets" where the receiver is on the ground) comprising the steps of: receiving a RF signal at the ground-based device corresponding to a plurality of RF transmissions from a satellite (Page 5506, Introduction, paragraph 3, lines 3-4, "1) design specialized receivers that can extract navigation observables from these signals”; Page 5506 Abstract, “A receiver architecture to acquire and track LEO satellite signals and extract Doppler measurements to LEO satellites is discussed” where a LEO satellite will cycle through breaking transmission and transmitting multiple times as it orbits, so it will transmit within an interval of time); said RF signal exhibiting a Doppler effect (Page 5506, Introduction, paragraph 3, lines 7-12, "This paper tackles the first two challenges…by discussing a receiver architecture to extract Doppler measurements from such signals and proposing a framework for positioning with the LEO satellite Doppler measurements"); determining whether the RF signal is from a satellite of interest (Page 5506, Introduction, paragraph 4, lines 1-3, "Extracting Doppler measurements from QPSK signals transmitted by LEO satellites can be achieved through carrier synchronization” where the carrier synchronization confirms that the ground device is communicating with the correct satellite), a satellite of interest having known data enabling an estimation of a current position of the satellite (Page 5506, Introduction, paragraph 2, lines 15-16, "Using TLEs and orbit determination algorithms (e.g., SGP 4), the positions and velocities of these satellites can be known"); utilizing a received RF signal of the satellite of interest to collect observed Doppler measurements of the received RF signal and time of receipt of the RF signal (Page 5506, Introduction, paragraph 4, lines 1-3, "Extracting Doppler measurements from QPSK signals transmitted by LEO satellites can be achieved through carrier synchronization”; and Page 5506, Introduction, paragraph 4, lines 12-15, "An extended Kalman filter (EKF) is employed to simultaneously estimate the receiver's position and the difference between the receiver's and each of the LEO satellites' clock drifts" where comparing clock drift involves the time a signal is received); estimating the position of the satellite of interest as a function of the known data for the satellite of interest (Page 5507, 2.3 Pseudorange Rate Measurement Model, paragraph 1, lines 1-6, "The receiver produces pseudorange rate measurements to the l-th satellite, which can be related to the Doppler frequency at time-step k using [equation 1] where f_D is the measured Doppler frequency to the l-th satellite, f_c,t is the carrier frequency at which the l-th satellite is transmitting" where the pseudorange rate involves knowing the satellites position); and determining the position, navigation and timing solution for the ground based device as a function of the observed Doppler measurements, to enable an estimation of the current location of the receiver (Page 5506, Introduction, paragraph 3, lines 3-4, "1) design specialized receivers that can extract navigation observables from these signals” and Page 5506-5507, Model Description, paragraph 1, lines 2-7, "The receiver listens to multiple LEO satellite downlink channels, where direct QPSK signals are transmitted. The receiver makes Doppler frequency measurements to each of the available LEO satellites and uses these measurements along with altimeter measurements to estimate its position using and EKF").
Khalife does not disclose discrete in time RF transmissions; predicting Doppler measurements for the satellite of interest as a function of the known data.
Zhodzishsky discloses
Discrete in time RF transmissions (Column 4 lines 34-37, "A strobed version of the satellite's PR-code signal may comprise a sequence of short strobe-pulses, each pulse corresponding to a boundary (also called end) between two chips of the input PR-code signal"); predicting Doppler measurements for the satellite of interest as a function of the known data (Column 33 lines 45-48, "A less precise method may use the form (r.sub.K r.sub.C)*K.sub.S, which essentially relies upon the prediction of the Doppler shift provided by the navigator unit" which is one of two methods mentioned in that paragraph that both improve the phased locked loop).
Khalife discloses radar transmissions and Doppler shifts but it does not disclose discrete time transmissions or predicting Doppler shifts.
Khalife using time discrete transmissions instead of continuously transmitting can reduce power consumption while the satellite maintains the ability to communicate. As such it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify Khalife with Zhodzishsky to improve the energy efficiency of the satellite.
Khalife’s invention depends on the movement/orbits of the satellites. Knowledge of future movements (which involve future Doppler shifts), would improve the invention as it would not have to spend as much time and resources searching for the relevant satellites. Therefore, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify Khalife with Zhodzishsky to improve Khalife’s ability to find the satellites it is tracking through predictions. Additionally, future knowledge of a satellites’ movement would mitigate potential collisions which would assist in the continued operation of the invention.
Regarding claim 2, the combination of Khalife and Zhodzishsky discloses
The method of claim 1. Khalife further discloses wherein a relative velocity of the satellite of interest is estimated from the known data for the satellite of interest (Page 5506, Introduction, paragraph 3, lines 3-7, “1) design specialized receivers that can extract navigation observables from these signals, 2) develop navigation frameworks that can account for the unknown nature of the LEO satellite SOP states (namely clock bias, drift, and/or position and velocity), and 3) characterize their error budgets”; Page 5506, Introduction, paragraph 2, lines 15-16, "Using TLEs and orbit determination algorithms (e.g., SGP 4), the positions and velocities of these satellites can be known").
Regarding claim 3, the combination of Khalife and Zhodzishsky discloses
The method of claim 2. Khalife further discloses wherein the known data for the satellite of interest includes two line element data (Page 5506, Introduction, paragraph 2, lines 15-16, "Using TLEs and orbit determination algorithms (e.g., SGP 4), the positions and velocities of these satellites can be known").
Regarding claim 5, the combination of Khalife and Zhodzishsky discloses
The method of claim 1. Khalife further discloses further comprising the step of providing a clock, the clock outputting a current time, and the method further comprising selecting data to estimate which satellites of interest may be in view to the receiver at the current time (Page 5506, Introduction, paragraph 4, lines 1-7, “Extracting Doppler measurements from QPSK signals transmitted by LEO satellites can be achieved through carrier synchronization…However, since these signals are being used opportunistically, one cannot assume that the receiver and satellites' clocks are synchronized. Therefore, the receiver's and satellite transmitters' clock drifts must be accounted for” where accounting for the clock drift requires a current/up-to-date clock and carrier signal synchronization, and its success, determines which satellites are in view of the receiver).
Regarding claim 6, the combination of Khalife and Zhodzishsky discloses
The method of claim 3. Khalife further discloses further comprising the step of periodically updating the known data (Page 5506, Introduction, paragraph 2, lines 11-14, “Moreover, the Keplerian elements parameterizing the orbits of these LEO satellites are made publicly available by the North American Aerospace Defense Command (NORAD) and are updated daily in the two-line element (TLE) files”).
Regarding claim 7 Khalife discloses,
A ground based device having a system for determining a positioning navigation and timing solution (Page 5506, Introduction, paragraph 3, lines 3-7, "1) design specialized receivers that can extract navigation observables from these signals, 2) develop navigation frameworks that can account for the unknown nature of the LEO satellite SOP states (namely clock bias, drift, and/or position and velocity), and 3) characterize their error budgets" where the receiver is on the ground), the system comprising; a satellite observation engine receiving RF signals from a satellite of interest (Page 5506, Introduction, paragraph 3, lines 3-4, "1) design specialized receivers that can extract navigation observables from these signals” where the receiver performs the same function as the satellite observation engine) and isolating and identifying one or more transmissions of interest therefrom as observations (Page 5506, Introduction, paragraph 4, lines 1-3, "Extracting Doppler measurements from QPSK signals transmitted by LEO satellites can be achieved through carrier synchronization” where focusing on the carrier frequency ignores noise form other non-relevant satellites and the carrier synchronization confirms that the ground device is communicating with the correct satellite); a closed loop service that stores known satellite information regarding the satellite of interest (Page 5508 3.2. Navigation Receiver Architecture, “The navigation receiver employs independent phase-locked loops (PLLs) to track the LEO satellite signal on each of the L channels. The Doppler shifts produced by the PLLs are then passed to the navigation filter” where a phased lock loop is a closed loop); and a LEO PNT service receiving the observations from the satellite observation engine, Doppler measurements and time of receipt (Page 5506, Introduction, paragraph 3, lines 3-7, “1) design specialized receivers that can extract navigation observables from these signals, 2) develop navigation frameworks that can account for the unknown nature of the LEO satellite SOP states (namely clock bias, drift, and/or position and velocity), and 3) characterize their error budgets”; Page 5506, Introduction, paragraph 3, lines 7-12, “This paper tackles the first two challenges…by discussing a receiver architecture to extract Doppler measurements from such signals and proposing a framework for positioning with the LEO satellite Doppler measurements) determining a position fix for the receiver (Page 5506-5507, 2.1. Problem Formulation, “The receiver makes Doppler frequency measurements to each of the available LEO satellites and uses these measurements along with alitmeter measurements to estimate its position” which is tantamount to a position fix for a receiver)
Khalife does not disclose discrete in time RF transmissions; a Doppler prediction engine that utilizes the satellite information stored in the closed loop service for each observed satellite and constructs a set of predicted Doppler measurements for satellites from which signals are received.
Zhodzishsky discloses
Discrete in time RF transmissions (Column 4 lines 34-37, "A strobed version of the satellite's PR-code signal may comprise a sequence of short strobe-pulses, each pulse corresponding to a boundary (also called end) between two chips of the input PR-code signal"); a Doppler prediction engine that utilizes the satellite information stored in the closed loop service for each observed satellite and constructs a set of predicted Doppler measurements for satellites from which signals are received (Column 31 lines 5-12, "In this embodiment, a PLL discriminator output E.sub.PK is generated at the slower rate as the phase-error signal for the channel's PLL loop, while a faster changing version E.sub.OK of the PLL discriminator output is generated as the PLL's phase output signal for the common loop. This saves on processor load since all of the channel PLLs (and DLLs also) are not updated at the same rate as the common loop (version E.sub.OK)" where a phase lock loop is a closed loop and it saves the Doppler data, and here it is using the saved data to help with tracking; Column 33 lines 45-48, "A less precise method may use the form (r.sub.K r.sub.C)*K.sub.S, which essentially relies upon the prediction of the Doppler shift provided by the navigator unit" where it is predicting Doppler shift which requires Doppler data).
Khalife discloses radar transmissions and Doppler shifts but it does not disclose discrete time transmissions or predicting Doppler shifts.
Khalife using time discrete transmissions instead of continuously transmitting can reduce power consumption while the satellite maintains the ability to communicate. As such it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify Khalife with Zhodzishsky to improve the energy efficiency of the satellite.
Khalife’s invention depends on the movement/orbits of the satellites. Knowledge of future movements (which involve future Doppler shifts), would improve the invention as it would not have to spend as much time and resources searching for the relevant satellites. Additionally, as PLL save Doppler shift data and the navigation unit predicts Doppler shifts it would be obvious to use the saved Doppler data for the predictions, especially since that data is already used to determine differences. Therefore, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify Khalife with Zhodzishsky to improve Khalife’s ability to find the satellites it is tracking through predictions. Additionally, future knowledge of a satellites’ movement would mitigate potential collisions which would assist in the continued operation of the invention.
Regarding claim 8, the combination of Khalife and Zhodzishsky discloses
The ground based device of claim 7. Khalife further discloses, further comprising a closed loop service storing the known satellite information about the satellite of interest (Page 5508 3.2. Navigation Receiver Architecture, “The navigation receiver employs independent phase-locked loops (PLLs) to track the LEO satellite signal on each of the L channels. The Doppler shifts produced by the PLLs are then passed to the navigation filter”; Page 5506, Introduction, paragraph 2, lines 11-14, “Moreover, the Keplerian elements parameterizing the orbits of these LEO satellites are made publicly available by the North American Aerospace Defense Command (NORAD) and are updated daily in the two-line element (TLE) files” where a phased lock loop is a closed loop and it can identify the satellite as with the TLE).
Regarding claim 9, the combination of Khalife and Zhodzishsky discloses
The ground based device of claim 7. Khalife further discloses where in the known information is two line element information (Page 5506, Introduction, paragraph 2, lines 11-14, “Moreover, the Keplerian elements parameterizing the orbits of these LEO satellites are made publicly available by the North American Aerospace Defense Command (NORAD) and are updated daily in the two-line element (TLE) files”).
Regarding claim 10, the combination of Khalife and Zhodzishsky discloses
The ground based device of claim 8. Khalife further discloses wherein the closed loop service receives updated information from a remote source and updates the known satellite information as a function thereof (Page 5506, Introduction, paragraph 2, lines 11-14, “Moreover, the Keplerian elements parameterizing the orbits of these LEO satellites are made publicly available by the North American Aerospace Defense Command (NORAD) and are updated daily in the two-line element (TLE) files”).
Regarding claim 11, the combination of Khalife and Zhodzishsky discloses
The ground based device of claim 7. Khalife further discloses further comprising a satellite selection function tuning the system to the specific frequencies for one or more satellites of interest (Page 5506, Introduction, paragraph 4, lines 1-3, "Extracting Doppler measurements from QPSK signals transmitted by LEO satellites can be achieved through carrier synchronization” where the carrier synchronization confirms that the ground device is communicating with the correct satellite).
Regarding claim 12, the combination of Khalife and Zhodzishsky discloses
The ground based device of claim 7. Khalife discloses further comprising satellite information from an outside source (Page 5506, Introduction, paragraph 2, lines 11-14, “Moreover, the Keplerian elements parameterizing the orbits of these LEO satellites are made publicly available by the North American Aerospace Defense Command (NORAD) and are updated daily in the two-line element (TLE) files”) and determines a position of the satellite of interest (Page 5506, Introduction, paragraph 2, lines 15-16, “Using TLEs and orbit determination algorithms (e.g., SGP 4), the positions and velocities of these satellites can be known”). Khalife does not disclose a LEO satellite prediction engine receiving observations from the satellite observation engine.
Zhodzishsky discloses
A LEO satellite prediction engine receiving observations from the satellite observation engine (Column 33 lines 45-48, "A less precise method may use the form (r.sub.K r.sub.C)*K.sub.S, which essentially relies upon the prediction of the Doppler shift provided by the navigator unit"; Column 31 lines 5-12, "In this embodiment, a PLL discriminator output E.sub.PK is generated at the slower rate as the phase-error signal for the channel's PLL loop, while a faster changing version E.sub.OK of the PLL discriminator output is generated as the PLL's phase output signal for the common loop. This saves on processor load since all of the channel PLLs (and DLLs also) are not updated at the same rate as the common loop (version E.sub.OK)" where the PLL store the Doppler data which is from observations).
Khalife’s invention depends on the movement/orbits of the satellites. Knowledge of future movements (which involve future Doppler shifts), would improve the invention as it would not have to spend as much time and resources searching for the relevant satellites. Therefore, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify Khalife with Zhodzishsky to improve Khalife’s ability to find the satellites it is tracking through predictions. Additionally, future knowledge of a satellites’ movement would mitigate potential collisions which would assist in the continued operation of the invention.
Regarding claim 13, the combination of Khalife and Zhodzishsky discloses
The ground based device of claim 12. Khalife discloses a closed loop service storing the known satellite information about the satellite of interest (Page 5508 3.2. Navigation Receiver Architecture, “The navigation receiver employs independent phase-locked loops (PLLs) to track the LEO satellite signal on each of the L channels. The Doppler shifts produced by the PLLs are then passed to the navigation filter”; Page 5506, Introduction, paragraph 2, lines 11-14, “Moreover, the Keplerian elements parameterizing the orbits of these LEO satellites are made publicly available by the North American Aerospace Defense Command (NORAD) and are updated daily in the two-line element (TLE) files” where a phased lock loop is a closed loop and it can identify the satellite as with the TLE). Khalife does not disclose wherein the Doppler prediction engine receives the known information from the closed loop service, and constructs a set of predicted Doppler measurements for all satellites for which signals are received.
Zhodzishsky discloses
A closed loop service storing the known satellite information about the satellite of interest , and wherein the Doppler prediction engine receives the known information from the closed loop service, and constructs a set of predicted Doppler measurements for all satellites for which signals are received (Column 31 lines 5-12, "In this embodiment, a PLL discriminator output E.sub.PK is generated at the slower rate as the phase-error signal for the channel's PLL loop, while a faster changing version E.sub.OK of the PLL discriminator output is generated as the PLL's phase output signal for the common loop. This saves on processor load since all of the channel PLLs (and DLLs also) are not updated at the same rate as the common loop (version E.sub.OK)" where a phase lock loop is a closed loop and it saves the Dopper data, and here it is using the saved data to help with tracking; Column 33 lines 45-48, "A less precise method may use the form (r.sub.K r.sub.C)*K.sub.S, which essentially relies upon the prediction of the Doppler shift provided by the navigator unit" where it is predicting Doppler shift which requires Doppler data).
Khalife and Weng are considered analogous arts as they both concern navigation via a ground receiver communicating with a satellite. Khalife’s invention depends on the movement/orbits of the satellites. Knowledge of future movements (which involve future Doppler shifts), would improve the invention as it would not have to spend as much time and resources searching for the relevant satellites. As Weng notes, Col 2, lines 15-19, "the remote receiver acquires the satellite signals using the AA data [that has the predictions] within the range of the window so as to avoid from searching the satellite in the widest range (i.e. all the Doppler shifts and all the code phases)." Therefore, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify Khalife with Weng to improve Khalife’s ability to find the satellites it is tracking through predictions. Additionally, future knowledge of a satellites’ movement would mitigate potential collisions which would assist in the continued operation of the invention.
Khalife’s invention depends on the movement/orbits of the satellites. Knowledge of future movements (which involve future Doppler shifts), would improve the invention as it would not have to spend as much time and resources searching for the relevant satellites. Additionally, as PLL save Doppler shift data and the navigation unit predicts Doppler shifts it would be obvious to use the saved Doppler data for the predictions, especially since that data is already used to determine differences. Therefore, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify Khalife with Zhodzishsky to improve Khalife’s ability to find the satellites it is tracking through predictions. Additionally, future knowledge of a satellites’ movement would mitigate potential collisions which would assist in the continued operation of the invention.
Claims 4 is rejected under 35 U.S.C. 103 as being unpatentable over Khalife Joe J et al: "Receiver Design for Doppler Positioning with Leo Satellites", ICASSP 2019 - 2019 IEEE International Conference On Acoustics, Speech and Signal Processing (ICASSP), IEEE, 12 May 2019 (2019-05-12), pages 5506-5510, XP033565135, DOI: 10.1109/ICASSP.2019.8682554 in view of Zhodzishsky (US 6313789 B1) further in view of Weng (US 8120530 B2).
Regarding claim 4, the combination of Khalife and Zhodzishsky discloses
The method of claim 1. The combination of Khalife and Zhodzishsky does not disclose predicting future Doppler measurements as a function of current location of the ground based device and the known information.
Weng discloses
Developing a predicted set of Doppler measurements as a function of current location of the ground based device and the known information (Figure Col 1, line 30-34, “The orbit determination technology and satellite trajectory prediction can be implemented by using a plenty of ranging observations from reference ground network stations, which can be simply referred to as ground observations”).
Khalife and Weng are considered analogous arts as they both concern navigation via a ground receiver communicating with a satellite. Khalife’s invention depends on the movement/orbits of the satellites. Knowledge of future movements (which involve future Doppler shifts), would improve the invention as it would not have to spend as much time and resources searching for the relevant satellites. As Weng notes, Col 2, lines 15-19, "the remote receiver acquires the satellite signals using the AA data [that has the predictions] within the range of the window so as to avoid from searching the satellite in the widest range (i.e. all the Doppler shifts and all the code phases)." Additionally, as the invention is used for navigation, the position of the ground device will also be required. Therefore, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify Khalife with Weng to improve Khalife’s ability to find the satellites it is using for navigation purposes. Additionally, future knowledge of a satellites’ movement would mitigate potential collisions which would assist in the continued operation of the invention.
Conclusion
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/PETER DAVON DOZE/Examiner, Art Unit 3648
/OLUMIDE AJIBADE AKONAI/Primary Examiner, Art Unit 3648
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