Doppler Null Scanning for Assured PNT Without Spatial Data Exchange
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Solution Overview
Problem
Existing PNT systems are vulnerable to errors and disruptions from intentional and non-intentional threats, such as satellite damage, interference, and spoofing, necessitating high availability and integrity solutions like Assured-PNT (A-PNT).
Innovation Solution
A system utilizing Doppler null scanning (DNS) for passive spatial awareness, enabling a receiver node to determine bearing and relative position with a transmitter node by applying Doppler corrections based on a common reference frame, without explicit data exchange, thereby providing PNT solutions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional PNT systems use GPS/GNSS satellites for positioning and timing, then global coverage and accuracy are improved, but vulnerability to intentional interference, spoofing, and satellite damage increases
Solution Approach 1:
The patent introduces Doppler null scanning as an intermediary mechanism between transmitter and receiver nodes. By scanning through Doppler frequency shifts and identifying the null point (where Doppler compensation is perfect), the system derives spatial awareness information without relying on vulnerable satellite PNT signals. This intermediary approach provides a alternative path for obtaining positioning and timing information that is resilient to GPS/GNSS interference and spoofing.
Solution Approach 2:
The system enables nodes to determine their own position, velocity, and timing information through self-contained Doppler null scanning measurements. Each receiver node independently scans Doppler frequencies and calculates its spatial state relative to transmitter nodes without requiring external PNT infrastructure. This self-service capability eliminates dependence on vulnerable satellite systems and provides assured PNT in contested environments.
2Measurement precision
If nodes exchange explicit spatial data to achieve spatial awareness, then positioning accuracy is improved, but communication overhead and system complexity increase
Solution Approach 1:
The patent replaces the mechanical/communication-based system of explicit spatial data exchange with a physics-based Doppler frequency measurement system. Instead of nodes communicating their positions through data packets, the system uses Doppler frequency shifts inherent in the radio frequency signals themselves to derive spatial information. This substitution eliminates the need for separate spatial awareness communication channels and reduces overall system complexity.
Solution Approach 2:
Nodes automatically derive spatial awareness information from the Doppler characteristics of received signals without requiring explicit data exchange with other nodes. The receiver independently processes the Doppler frequency content and calculates bearing, range rate, and position information, eliminating the need for complex inter-node communication protocols for spatial coordination.
3Adaptability or versatility
If Doppler corrections are applied without time synchronization, then operational flexibility is improved, but measurement precision deteriorates
Solution Approach 1:
The patent implements time synchronization as a preliminary action before performing Doppler null scanning and spatial awareness calculations. By establishing a common time reference between transmitter and receiver nodes in advance, the system ensures that Doppler frequency measurements are referenced to a consistent time base. This preliminary synchronization enables accurate Doppler corrections while maintaining the flexibility of the DNS approach for deriving spatial information.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
DNS enables efficient discovery and synchronization of network nodes, eliminating the need for active spatial awareness via data communication, enhancing network topology learning and improving mobile ad hoc networking by providing reliable PNT information.
Implementation Method 1
The receiver node is time synchronized with a transmitter node to apply Doppler corrections to the receiver node's own motions relative to a common reference frame
Implementation Method 2
use Doppler null scanning (DNS) to determine DNS derived information, the DNS derived information including a bearing and the receiver node's relative position relative to the transmitter node
Data Source
AI summary
A system may include a receiver node. The receiver node may include a communications interface and a controller. The receiver node is time synchronized with a transmitter node to apply Doppler corrections to the receiver node's own motions relative to a common reference frame. The receiver node may be configured to: The receiver node may be configured to: based at least on the receiver node being time synchronized with the transmitter node to apply Doppler corrections and the common reference frame, use Doppler null scanning (DNS) to determine DNS derived information, the DNS derived information including a bearing and the receiver node's relative position relative to the transmitter node; and output a position, navigation, and timing (PNT) solution based at least on the DNS derived information.