Cellular Signal Navigation for UAVs in GNSS Denied Environments
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Solution Overview
Problem
Current UAV navigation systems are inadequate for resilient, accurate, and tamper-proof navigation, especially in environments where GNSS signals are unreliable or unavailable, due to unknown states of cellular base transceiver stations and difficulties in resolving ambiguities for submeter-level accuracy.
Innovation Solution
The development of systems and methods using cellular communication signals for navigation, employing a differential and non-differential framework that includes carrier phase measurements, a weighted nonlinear least squares estimator, and an extended Kalman filter to determine precise position estimates and control navigation, even in the absence of GNSS signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional approaches use multiple-frequency measurements or GNSS satellite geometry to achieve submeter-level navigation, then navigation accuracy is improved, but the system becomes vulnerable to jamming and spoofing, and may not be usable in certain environments
Solution Approach 1:
The patent applies multi-functionality by using cellular communication signals for both navigation and positioning purposes simultaneously. The system processes cellular signals to extract both location information and timing data, enabling the same signal infrastructure to serve multiple functions and reducing dependency on dedicated navigation satellites that are vulnerable to jamming.
Solution Approach 2:
The patent introduces ground-based cellular base stations as intermediary reference points between the UAV and the navigation system. These base stations serve as mediators that provide known position references and timing signals, enabling the UAV to determine its position relative to these stable ground-based references rather than relying directly on vulnerable satellite signals.
2Adaptability or versatility
If the system uses cellular base transceiver stations for navigation, then coverage and availability are improved, but the unknown states of BTS positions and clock errors worsen measurement precision
Solution Approach 1:
The patent implements feedback by continuously estimating and updating the states of cellular base transceiver stations using multiple measurement techniques. The system uses carrier phase measurements and pseudorange data to iteratively refine estimates of BTS positions and clock errors, feeding this information back into the navigation solution to improve accuracy over time rather than relying on static or pre-known BTS states.
Solution Approach 2:
The patent segments the navigation problem into separate estimation components for BTS position and clock error states. By dividing the overall state estimation into distinct segments that can be processed independently through different measurement types (carrier phase for position, pseudorange for timing), the system can address each uncertainty separately and combine the results for improved overall precision.
3Measurement precision
If conventional approaches rely on dedicated ground-based GPS integrity beacons to guarantee navigation performance, then measurement precision is improved, but device complexity and system cost increase
Solution Approach 1:
The patent applies multi-functionality by enabling existing cellular base stations to serve dual purposes: their primary communication function and their secondary function as navigation reference points. This eliminates the need for dedicated GPS integrity beacons or specialized ground infrastructure, as the same cellular towers provide both communication services and navigation positioning data.
Solution Approach 2:
The patent implements self-service by allowing the cellular network infrastructure to provide its own navigation capabilities without requiring separate dedicated systems. The cellular base stations automatically provide positioning and timing information as part of their normal operation, and the UAV navigation system utilizes these self-provided signals without needing external dedicated beacon infrastructure.
Data Source
AI summary
Processes and device configurations are provided for navigation using communications signal observables and using differential and non-differential frameworks. Communication signals, such as cellular communication signals may be used to obtain position estimates of a device such as a rover or unmanned aerial vehicle. Frameworks are provided for determination of position estimates with and without the use of a base station device. Processes can include use of position estimates to aid navigation.