Doppler Cellular Navigation Using Ground-Based RF Emitter Shifts
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Solution Overview
Problem
Current navigation systems, such as GNSS and INS, face limitations including multipath signals, satellite interference, jamming, spoofing, and drift errors, which can compromise their accuracy and reliability, especially in urban environments and over time.
Innovation Solution
A doppler based cellular navigation system that uses RF signals from ground-based emitters to determine vehicle location by monitoring doppler shifts and utilizing a database of emitter locations, allowing for standalone operation or supplementation of other navigation systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS is used for navigation, then high precision position and time information is provided, but the system is vulnerable to multipath signals, satellite interference, jamming, spoofing, and intentional degradation
Solution Approach 1:
The patent introduces ground-based RF emitters (cell towers) as intermediary reference points between the vehicle and the ultimate navigation goal. Instead of relying solely on vulnerable satellite signals, the system uses terrestrial RF signals that are less susceptible to jamming and spoofing, providing a reliable backup reference frame for position determination
Solution Approach 2:
The system transitions from using satellite-based electromagnetic signals to ground-based RF signals with different propagation characteristics. By monitoring Doppler shift parameters of terrestrial signals, the system achieves reliable position information that is not dependent on satellite signal integrity
2Productivity
If INS is used for navigation, then relative measurements are provided, but drift errors accumulate over time
Solution Approach 1:
The patent implements a feedback mechanism where the Doppler-based cellular navigation system periodically corrects the drift errors in INS. By comparing INS-derived position with position determined from ground-based RF emitter Doppler shifts, the system resets accumulated errors and maintains long-term accuracy
Solution Approach 2:
The system creates a composite navigation solution by combining INS (inertial navigation system) with Doppler-based cellular navigation. This hybrid approach leverages the strengths of both systems: INS provides continuous relative measurements while the cellular system provides periodic absolute position references to correct drift
3Reliability
If backup navigation system is implemented, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent makes the vehicle's existing RF receiver serve multiple functions: it receives both satellite navigation signals and ground-based cellular RF signals. This multi-functionality allows the system to operate in multiple modes (GNSS-only, cellular-only, or hybrid) without requiring completely separate hardware systems, thereby reducing overall complexity while maintaining reliability
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
The system provides effective and efficient location determination that is not inhibited by the disabling of other navigation systems, is not limited by user numbers, requires minimal infrastructure, and operates in all weather conditions, effectively addressing the limitations of existing systems.
Implementation Method 1
The controller is configured to monitor a doppler shift in received RF signals from ground-based RF emitters
Data Source
AI summary
A vehicle having a doppler based cellular navigation system is provided. The vehicle includes a radio frequency (RF) antenna, an RF receiver in communication with the RF antenna, a memory and a controller. The memory includes a ground-based RF emitter database with ground-based RF emitter location information. The controller is in communication with the RF receiver and the memory. The controller is configured to monitor a doppler shift in received RF signals from ground-based RF emitters. The controller is further configured to determine location information when the controller detects a doppler shift in a received RF signal of zero. The controller is further configured to implement the determined location information in navigating a vehicle.