Nonlinear Intermodulation Distance Determination for Aircraft
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Solution Overview
Problem
Traditional methods for determining an aircraft's altitude, such as sonar and radar, are often inaccurate due to turbulence and noise, and can be costly or complex, especially for small aircraft flying over varying terrains like water.
Innovation Solution
A nonlinear intermodulation distance determination system that transmits pairs of sonic pulses at different frequencies and detects intermodulation products to determine altitude, using a binary approach that is less affected by noise and turbulence, and can iteratively refine distance measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional sonar or radar methods are used to determine aircraft altitude, then altitude measurement can be achieved, but accuracy deteriorates due to turbulence and noise interference
Solution Approach 1:
The patent uses intermodulation products as an intermediary signal that is inherently less susceptible to turbulence and noise. By transmitting two different frequencies and detecting their intermodulation product (a third frequency created by nonlinear interaction), the system creates a derived signal that preserves altitude information while being more robust against environmental interference than the original frequencies.
Solution Approach 2:
The system changes the frequency parameter by transmitting multiple frequencies and detecting their intermodulation product. This parameter transformation allows the system to measure altitude at a derived frequency that is less affected by turbulence and noise, effectively converting a noisy measurement problem into a cleaner measurement at a different frequency.
2Measurement precision
If traditional radar systems are used for altitude determination, then measurement capability is provided, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex radar systems with a simpler acoustic-based intermodulation detection system. Instead of using sophisticated electromagnetic radiation and reception equipment, the invention uses transmitted sonic pulses and detects their intermodulation products, achieving altitude measurement with a less complex and more cost-effective system architecture.
Solution Approach 2:
The system creates a simplified copy of the altitude measurement function using intermodulation detection rather than direct radar or sonar measurement. By transmitting reference frequencies and detecting their nonlinear interaction products, the system replicates altitude determination capability through a different, simpler mechanism that avoids the complexity of traditional systems.
3Object-affected harmful factors
If binary detection approach is used, then noise resistance improves, but measurement detail may be reduced
Solution Approach 1:
The patent employs feedback by iteratively adjusting the transmitted frequencies and analyzing the detected intermodulation products. The system uses the binary detection results as feedback to refine frequency selections and improve measurement detail, allowing it to maintain noise resistance while progressively achieving more precise altitude measurements through iterative refinement.
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 system provides a more accurate and cost-effective method for determining an aircraft's altitude above various surfaces by exploiting acoustic reflection, with improved accuracy and reduced noise interference compared to traditional sonar systems, and is particularly suitable for small aircraft.
Implementation Method 1
A nonlinear intermodulation distance determination system that transmits pairs of sonic pulses at different frequencies and detects intermodulation products to determine altitude, using a binary approach that is less affected by noise and turbulence
Implementation Method 2
The system comprises a processor coupled to the receiver and configured to detect whether an intermodulation product of the first pulse and the second pulse is present in an audio signal received by the receiver
Data Source
AI summary
A distance determination system is disclosed. In various embodiments, the system includes a transmitter configured to transmit a first pulse at a first frequency and a second pulse at a second frequency; a receiver configured to receive audio signals; and a processor coupled to the receiver and configured to detect whether an intermodulation product of the first pulse and the second pulse is present and above a threshold amplitude in an audio signal received by the receiver; and determine, based at least in part on whether the intermodulation product of the first pulse and the second pulse is detected to be present and above a threshold amplitude, whether a distance to a surface is greater than a distance corresponding to the first pulse and the second pulse.