Millimeter Wave Navigation for UAV GPS Denial
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Solution Overview
Problem
Unmanned aerial vehicles (UAVs) face challenges in maintaining accurate position estimates when GPS signals are lost, leading to increased errors over time and forcing them into emergency modes, especially when operating beyond visual line of sight.
Innovation Solution
The implementation of millimeter wave assisted navigation systems using frequency-modulated continuous wave (FMCW) radar signals, which generate and transmit radio waves, determine individual beam velocities, and combine them to provide a body velocity vector, enabling real-time position and velocity information even without GPS signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS signal is used for navigation, then position accuracy is maintained, but navigation fails when GPS signal is lost or blocked
Solution Approach 1:
The patent introduces radar systems as an intermediary navigation method that operates independently of GPS satellites. The radar provides position and velocity estimates through active sensing of the environment, serving as a mediator when GPS signals are unavailable, thereby maintaining navigation reliability under GPS denial conditions
Solution Approach 2:
The system transitions between different navigation parameters and methods based on GPS availability. When GPS is available, it uses satellite-based position estimates; when GPS is denied, it switches to radar-based active sensing parameters, changing the operational mode to maintain continuous navigation capability
2Reliability
If IMU is used for position estimation during GPS loss, then brief navigation continuity is maintained, but positioning error increases over time
Solution Approach 1:
The radar system provides continuous feedback on position and velocity estimates that can be used to correct accumulating IMU errors. By actively measuring the environment and comparing expected versus actual sensor data, the system generates corrective feedback to maintain measurement precision over extended periods without GPS
Solution Approach 2:
The patent merges multiple navigation systems (GPS, IMU, and radar) into an integrated navigation solution. The radar complements the IMU by providing external reference measurements, combining the strengths of inertial navigation (continuity) with active sensing (error correction) to maintain both reliability and precision
3Object-affected harmful factors
If UAV enters emergency mode during GPS loss, then vehicle safety is protected, but autonomous operation capability is lost
Solution Approach 1:
The system prepares alternative navigation methods (radar-based active sensing) in advance to cushion against GPS failure. By having a pre-configured backup navigation capability that maintains autonomous operation, the system avoids forced emergency landings while still protecting vehicle safety through controlled continuation of the mission
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
This solution allows UAVs to maintain accurate navigation and avoid emergency modes, enabling continued autonomous operation and remote control during GPS signal loss, improving positional and directional accuracy and expanding operational capabilities.
Implementation Method 1
determining, by a radar signal processor, individual beam velocities of the vehicle in each of the beam directions
Implementation Method 2
transmitting, by a plurality of radar transmitters each having a beam direction, the FMCW signal as radio waves; receiving, by a corresponding plurality of receivers, reflected radio signals
Data Source
AI summary
Disclosed are methods and systems for providing millimeter wave assisted vehicle navigation. A method may include generating a frequency-modulated continuous wave (FMCW) signal, transmitting the FMCW signal as radio waves by a plurality of radar transmitters each having a beam direction, receiving reflected radio signals by a corresponding plurality of receivers, and determining individual beam velocities of the vehicle in each of the beam directions. The method may further include combining the individual beam velocities; generating a body velocity vector based on the combined individual beam velocities; combining input from the radar signal processor and a previous known vehicle position; and based on the combined input, providing real-time position and velocity information for the vehicle.