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 .
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.
Claim(s) 1-23 is/are rejected under 35 U.S.C. 103 as being unpatentable over Sagiraju et al., US2015/0054686 A1, and further in view of MacDonald et al., US2019/0146092 A1.
Regarding claim 1, Sagiraju teaches A method for determining an electron density in a portion of an ionosphere (Abstract; methods provided for compensating for ionospheric delay in multi constellation Global Navigation Satellite Systems (GNSSs).) comprising: receiving, at a satellite in orbit, a signal transmitted from a ground-based transmitter through a portion of the ionosphere between the satellite and the ground transmitter (par. 0006; Delay from ionospheric interference can be almost completely corrected for by using multiple frequency observations, e.g., by transmitting and receiving signals at two different Global Positioning System (GPS) frequencies L1 and L2, from a single satellite.); receiving, at the satellite, a reflection of the signal from a portion of the ionosphere above the satellite (par. 0074; the receiver 100 receives a first signal at a first frequency f.sub.1 from a first satellite in a first GNSS constellation, e.g., satellite 110-1, and in step 403, receives a second signal at a second frequency f.sub.2 from a second satellite in a second GNSS constellation, e.g., satellite 120-1.).
Sagiraju fails to teach the following recited limitation. However, MacDonald teaches determining, based on the signal received at the satellite transmitted from the ground-based transmitter through the portion of the ionosphere between the satellite and the ground-based transmitter and the reflection of the signal received from the portion of the ionosphere above the satellite, an electron density of the portion of the ionosphere above the satellite (par. 0081; the ionosphere 208 three-dimensional electron density structure may be determined in a similar way as discussed above with respect to the air density, and may have an additional advantage in that certain satellite 226 constellations may orbit within the ionosphere 208 itself.). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine Sagiraju’s teachings and MacDonald’s teachings in order to have improved atmospheric and ionosphere three-dimensional density fields are used to constrain errors in GNSS navigation devices, allowing more accurate estimate of location (MacDonald, par. 0001).
Regarding claim 2, Sagiraju and MacDonald teach all the limitations in claim 1. Sagiraju further teaches wherein the electron density of the portion of the ionosphere above the satellite is determined by: computing a virtual height between the satellite and an altitude at which the signal reflected by the ionosphere (par. 0075); and inverting the virtual height to determine the electron density at the altitude (par. 0075).
Regarding claim 3, Sagiraju and MacDonald teach all the limitations in claim 2. Sagiraju further teaches wherein the virtual height is computed by multiplying one half of an amount of time between receiving the signal and receiving the reflection of the signal by the speed of light (par. 0021).
Regarding claim 4, Sagiraju and MacDonald teach all the limitations in claim 1. Sagiraju further teaches comprising: determining, based on a delay of the signal received through the portion of the ionosphere between the satellite and the ground transmitter, a total electron content (TEC) of the portion of the ionosphere between the satellite and the ground transmitter (par. 0040).
Regarding claim 5, Sagiraju and MacDonald teach all the limitations in claim 4. Sagiraju further teaches wherein determining at least one of the TEC and the electron density comprises using ray tracing to quantify an impact of at least one of non-specular reflection and earth’s magnetic field on the signal and the reflection of the signal (par. 0021).
Regarding claim 6, Sagiraju and MacDonald teach all the limitations in claim 4. Sagiraju further teaches wherein determining at least one of the TEC and the electron density comprises determining an impact of a doppler shift on the signal and the reflection of the signal (par. 0021).
Regarding claim 7, Sagiraju and MacDonald teach all the limitations in claim 1. Sagiraju further teaches wherein the signal comprises a plurality of frequencies between 3 and 30 MHz transmitted over a period of time (par. 0028).
Regarding claim 8, Sagiraju and MacDonald teach all the limitations in claim 7. Sagiraju further teaches comprising: for each frequency of the plurality of frequencies, determining a virtual height between the satellite and an altitude at which the respective frequency was reflected by the ionosphere; and inverting the virtual height to determine the electron density at the altitude at which the respective frequency was reflected (par. 0028).
Regarding claim 9, Sagiraju and MacDonald teach all the limitations in claim 8. Sagiraju further teaches comprising: determining an electron density profile (EDP) based on the electron density determined for each frequency (par. 0028).
Regarding claim 10, Sagiraju and MacDonald teach all the limitations in claim 1. Sagiraju further teaches wherein the portion of the ionosphere between the satellite and the ground-based transmitter comprises at least one of a portion of the E layer of the ionosphere and a portion of the F layer of the ionosphere (par. 0072).
Regarding claim 11, Sagiraju and MacDonald teach all the limitations in claim 1. Sagiraju further teaches wherein the portion of the ionosphere above the satellite comprises a portion of the F layer of the ionosphere (par. 0072).
Regarding claim 12, Sagiraju and MacDonald teach all the limitations in claim 1. Sagiraju further teaches wherein the satellite is positioned in very low earth orbit (VLEO) (par. 0072).
Regarding claim 13, Sagiraju and MacDonald teach all the limitations in claim 1. Sagiraju further teaches wherein the satellite is positioned below a height of a peak electron density of the F2 layer of the ionosphere (par. 0072).
Regarding claim 14, Sagiraju and MacDonald teach all the limitations in claim 1. Sagiraju further teaches wherein the signal transmitted from the ground-based transmitter is transmitted from less than 5,000 km from the satellite (par. 0021).
Regarding claim 15, Sagiraju and MacDonald teach all the limitations in claim 1. Sagiraju further teaches comprising: predicting an effect on at least one of the signal transmitted from the ground-based transmitter and a signal other than the signal transmitted from the ground-based transmitter based on at least one of the TEC and the EDP (par. 0040).
Regarding claim 16, Sagiraju and MacDonald teach all the limitations in claim 15. Sagiraju further teaches comprising: adjusting a characteristic of at least one of the signal transmitted from the ground-based transmitter and the signal other than the signal transmitted from the ground-based transmitter based on the predicted effect, wherein the characteristic comprises at least one of a frequency, a wavelength, an amplitude, a polarization, a transmission power, and a bandwidth (par. 0022).
Regarding claim 17, Sagiraju and MacDonald teach all the limitations in claim 1. Sagiraju further teaches comprising: generating a model of at least a portion of the ionosphere based on the electron density (par. 0049).
Regarding claim 18, Sagiraju and MacDonald teach all the limitations in claim 1. Sagiraju further teaches comprising: transmitting the signal from the ground-based transmitter (par. 0006).
Regarding claim 19, Sagiraju teaches A non-transitory computer readable storage medium storing instructions for determining an electron density in a portion of an ionosphere wherein the instructions are executable by a system comprising one or more processors (par. 0068; The memory 302, e.g., a non-transitory computer-readable medium, stores program instructions, e.g., software, that control the processor 301 to calculate the ionospheric delay using the received first signal and the received second signal.) to cause the system to: receive, at a satellite in orbit, a signal transmitted from a ground-based transmitter through a portion of the ionosphere between the satellite and the ground transmitter (par. 0006; Delay from ionospheric interference can be almost completely corrected for by using multiple frequency observations, e.g., by transmitting and receiving signals at two different Global Positioning System (GPS) frequencies L1 and L2, from a single satellite.); receive, at the satellite, a reflection of the signal from a portion of the ionosphere above the satellite (par. 0074; the receiver 100 receives a first signal at a first frequency f.sub.1 from a first satellite in a first GNSS constellation, e.g., satellite 110-1, and in step 403, receives a second signal at a second frequency f.sub.2 from a second satellite in a second GNSS constellation, e.g., satellite 120-1.).
Sagiraju fails to teach the following recited limitation. However, MacDonald teaches determine, based on the signal received at the satellite transmitted from the ground-based transmitter through the portion of the ionosphere between the satellite and the ground-based transmitter and the reflection of the signal received from the portion of the ionosphere above the satellite, an electron density of the portion of the ionosphere above the satellite (par. 0081; the ionosphere 208 three-dimensional electron density structure may be determined in a similar way as discussed above with respect to the air density, and may have an additional advantage in that certain satellite 226 constellations may orbit within the ionosphere 208 itself.). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine Sagiraju’s teachings and MacDonald’s teachings in order to have improved atmospheric and ionosphere three-dimensional density fields are used to constrain errors in GNSS navigation devices, allowing more accurate estimate of location (MacDonald, par. 0001).
Regarding claim 20, Sagiraju teaches A system (Fig. 1) comprising: a satellite (par. 0052; satellites 120-1, 120-2, . . . , 120-N); at least one receiver positioned on the satellite (par. 0067; receiver 100); and one or more processors and a memory, the memory storing one or more computer programs that include computer instructions, which when executed by the one or more processors (par. 0067; a processor 301, a memory 302).
Sagiraju fails to teach the following recited limitation. However, MacDonald teaches determine, based on a signal received at the receiver positioned on the satellite, the signal transmitted from a ground-based transmitter through a portion of the ionosphere between the satellite and the ground-based transmitter, and a reflection of the signal received from a portion of the ionosphere above the satellite, an electron density of the portion of the ionosphere above the satellite (par. 0081; the ionosphere 208 three-dimensional electron density structure may be determined in a similar way as discussed above with respect to the air density, and may have an additional advantage in that certain satellite 226 constellations may orbit within the ionosphere 208 itself.). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine Sagiraju’s teachings and MacDonald’s teachings in order to have improved atmospheric and ionosphere three-dimensional density fields are used to constrain errors in GNSS navigation devices, allowing more accurate estimate of location (MacDonald, par. 0001).
Regarding claim 21, Sagiraju and MacDonald teach all the limitations in claim 20. Sagiraju further teaches wherein the one or more processors are located at a ground station (par. 0013).
Regarding claim 22, Sagiraju and MacDonald teach all the limitations in claim 20. Sagiraju further teaches wherein the one or more processors are positioned on the satellite (par. 0013).
Regarding claim 23, Sagiraju and MacDonald teach all the limitations in claim 20. Sagiraju further teaches wherein the ground-based transmitter comprises an ionosonde (par. 0040).
Conclusion
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/AYODEJI O AYOTUNDE/Primary Examiner, Art Unit 2649
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