Resilient Distributed Positioning Networks for Co-Channel Beacon Separation
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Solution Overview
Problem
Current PNT systems face challenges in providing high-precision, low-latency positioning and timing for next-generation outdoor and indoor systems, are vulnerable to co-channel interference and jamming, and struggle to meet FCC accuracy and latency requirements for UAS traffic management and E911 applications.
Innovation Solution
Resilient Distributed Positioning Networks (RDPN) using flexible multitone navigation signals with spectral and temporal redundancy, enabling rapid and precise geolocation through network-provisioned co-channel beacons, leveraging SCSS modulation and code nulling methods to separate signals based on SNR rather than SIR, and utilizing a centralized network operation center for data processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS systems use correlative methods to detect signals and estimate geo-observables, then positioning information can be obtained, but time-to-first-fix exceeds 30 seconds in cold start scenarios and power consumption is hugely increased
Solution Approach 1:
The patent applies preliminary action by pre-synchronizing beacon transmitters to a common time reference and pre-assigning unique known codes to each transmitter. This allows receivers to immediately correlate incoming signals with known codes without needing to search through multiple possibilities, reducing cold start TTFF from over 30 seconds to under 1 second while maintaining positioning accuracy.
Solution Approach 2:
The patent changes the parameter of signal structure by using synchronized time slots and unique known codes for each beacon transmitter. This transforms the signal detection problem from a complex search through multiple hypotheses to a simple correlation with known patterns, dramatically reducing processing time and power consumption while preserving measurement precision.
2Area of stationary object
If multiple beacons transmit on the same time and frequency channel, then network density and coverage are improved, but co-channel interference and vulnerability to jamming increase
Solution Approach 1:
The patent applies segmentation by dividing the signal space into orthogonal components through unique known codes assigned to each beacon transmitter. This allows multiple beacons to transmit simultaneously on the same frequency channel without interfering with each other, as receivers can separately correlate with each unique code. This resolves the contradiction by enabling high network density and coverage while eliminating co-channel interference through code orthogonality.
3Adaptability or versatility
If GNSS receivers perform full search over all possible ranging codes and timing offsets, then cold start positioning is achieved, but power consumption is hugely increased and processing time exceeds 30 seconds
Solution Approach 1:
The patent applies preliminary action by pre-distributing unique known codes to all beacon transmitters and providing receivers with a code book containing all possible codes. This eliminates the need for receivers to perform exhaustive searches over unknown codes and timing offsets, reducing cold start power consumption and processing time from over 30 seconds to under 1 second while maintaining full cold start capability.
4Reliability
If beacon transmitters use high power to overcome path loss and provide coverage, then signal reception is improved, but vulnerability to jamming and spoofing attacks increases
Solution Approach 1:
The patent introduces an intermediary layer of unique known codes that mediate between the beacon transmitters and receivers. This code-based identification system allows receivers to distinguish legitimate beacons from jammers or spoofers, providing security without requiring high transmit power. The known codes act as an intermediary authentication mechanism that maintains signal reception reliability while reducing vulnerability to harmful attacks.
Data Source
AI summary
Co-channel beacon transmissions are provided with at least one of spectral redundancy and temporal redundancy. A receiver produces a snapshot of a superposition of received co-channel beacon transmissions. Subcarrier demodulation, code nulling, or a Class-C linear minimum-mean-square error (MMSE) operation separates multiples ones of the co-channel beacon transmissions or eliminates inter-symbol interference and inter-subcarrier interference in the snapshot. Receiver operations can be performed at a network user, a network node, or a network operations center.