# US 11,444,812 B2 · Resilient reception of navigation signals, using known self-coherence features of those signals > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,444,812 B2 - Document ID: US11444812B2 - Status: Granted - Kind: B2 - Application number: 17/170,477 - Filed: 2021-02-08 - Published: 2021-06-03 - Granted: 2022-09-13 - Earliest claimed: 2015-07-24 - Applicants: Brian G. Agee - Inventors: Brian G. Agee - Web page: https://patentgrep.com/patent/US11444812B2 ## CPC - H04L 25/08: Modifications for reducing interference; Modifications for reducing effects due to line faults {; Receiver end arrangements for detecting or overcoming line faults} - H04B 7/0617: {for beam forming} - H04L 27/264: {Pulse-shaped multi-carrier, i.e. not using rectangular window} - H04L 27/26414: {Filtering per subband or per resource block, e.g. universal filtered multicarrier [UFMC] or generalized frequency division multiplexing [GFDM]} - H04L 27/26538: {Filtering per subband or per resource block, e.g. universal filtered multicarrier [UFMC] or generalized frequency division multiplexing [GFDM]} - H04W 28/14: using intermediate storage - H04W 52/52: using AGC [Automatic Gain Control] circuits or amplifiers - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04B: TRANSMISSION - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract An apparatus and digital signal processing means are disclosed to reliably and rapidly receive and detect navigation signals, e.g., Global Navigation Satellite System (GNSS) signals, such as Global Position System (GPS) L1 legacy, L1C, and L5 signals, using combinations of spatially diverse antenna arrays, polarization-diverse antenna arrays, frequency-channelized analysis filters, and perfect-reconstruction synthesis filters, by exploiting features of those signals that are self-coherent over known framing intervals. Among other advantages, the means can reliably and rapidly identify navigation signals based on those features, improve their quality ahead of, or during, signal despreading operations, and detect and excise inadvertent or targeted electronic attack (EA) measures, e.g., navigation signal spoofers, and narrowband or wideband jamming and co-channel interference. In one aspect, the interference excision is performed in an appliqué that can be implemented without coordination with a navigation receiver. ## Claims ### Claim 1 A method, comprising: receiving a plurality of navigation signals from multiple antenna feeds of an antenna array; exploiting a known periodicity that is common to multiple ones of the plurality of navigation signals to compute a set of linear combining weights, the linear combining weights being configured to enable separation of the multiple ones of the plurality of navigation signals; and linearly combining the plurality of navigation signals to separate the multiple ones of the plurality of navigation signals. ### Claim 2 (depends on 1) The method of claim 1, wherein linearly combining is configured to perform dynamic interference cancellation and excision of at least one signal not of interest. ### Claim 3 (depends on 1) The method of claim 1, wherein exploiting comprises calculating the at least one set of linear combining weights based on temporal coherence peaks occurring at intervals corresponding to the known periodicity. ### Claim 4 (depends on 1) The method of claim 1, wherein the multiple antenna feeds comprises spatially diverse antenna feeds and/or polarization-diverse antenna feeds. ### Claim 5 (depends on 1) The method of claim 1, wherein receiving employs an analysis filter bank that frequency-channelizes received signals to produce the plurality of navigation signals. ### Claim 6 (depends on 1) The method of claim 1, wherein the plurality of navigation signals are Global Navigation Satellite System signals. ### Claim 7 (depends on 6) The method of claim 6, wherein the plurality of navigation signals are Global Positioning System signals. ### Claim 8 An apparatus comprising at least one processor, memory in electronic communication with the processor, and instructions stored in the memory, the instructions executable by the at least one processor for: receiving a plurality of navigation signals from multiple antenna feeds of an antenna array; exploiting a known periodicity that is common to multiple ones of the plurality of navigation signals to compute a set of linear combining weights, the linear combining weights being configured to enable separation of the multiple ones of the plurality of navigation signals; and linearly combining the plurality of navigation signals to separate the multiple ones of the plurality of navigation signals. ### Claim 9 (depends on 8) The apparatus of claim 8, wherein linearly combining is configured to perform dynamic interference cancellation and excision of at least one signal not of interest. ### Claim 10 (depends on 8) The apparatus of claim 8, wherein exploiting comprises calculating the at least one set of linear combining weights based on temporal coherence peaks occurring at intervals corresponding to the known periodicity. ### Claim 11 (depends on 8) The apparatus of claim 8, wherein the multiple antenna feeds comprises spatially diverse antenna feeds and/or polarization-diverse antenna feeds. ### Claim 12 (depends on 8) The apparatus of claim 8, wherein receiving employs an analysis filter bank that frequency-channelizes received signals to produce the plurality of navigation signals. ### Claim 13 (depends on 8) The apparatus of claim 8, wherein the plurality of navigation signals are Global Navigation Satellite System signals. ### Claim 14 (depends on 13) The apparatus of claim 13, wherein the plurality of navigation signals are Global Positioning System signals. ### Claim 15 A non-transitory computer-readable memory, and instructions stored thereon and executable by at least one processor for: receiving a plurality of navigation signals from multiple antenna feeds of an antenna array; exploiting a known periodicity that is common to multiple ones of the plurality of navigation signals to compute a set of linear combining weights, the linear combining weights being configured to enable separation of the multiple ones of the plurality of navigation signals; and linearly combining the plurality of navigation signals to separate the multiple ones the plurality of navigation signals. ### Claim 16 (depends on 15) The non-transitory computer-readable memory of claim 15, wherein linearly combining is configured to perform dynamic interference cancellation and excision of at least one signal not of interest. ### Claim 17 (depends on 15) The non-transitory computer-readable memory of claim 15, wherein exploiting comprises calculating the at least one set of linear combining weights based on temporal coherence peaks occurring at intervals corresponding to the known periodicity. ### Claim 18 (depends on 15) The non-transitory computer-readable memory of claim 15, wherein the multiple antenna feeds comprises spatially diverse antenna feeds and/or polarization-diverse antenna feeds. ### Claim 19 (depends on 15) The non-transitory computer-readable memory of claim 15, wherein receiving employs an analysis filter bank that frequency-channelizes received signals to produce the plurality of navigation signals. ### Claim 20 (depends on 15) The non-transitory computer-readable memory of claim 15, wherein the plurality of navigation signals are Global Navigation Satellite System signals.