Laser-Induced Plasma Channel Air Data Measurement
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Solution Overview
Problem
Current air data measurement systems, such as pitot tubes and LIDAR, face challenges like icing, bird strikes, and inefficiency at hypersonic speeds, and require large, heavy, and expensive lasers for high-altitude operations.
Innovation Solution
A system using a laser-induced plasma channel (LIPC) is created by emitting laser light into the air to induce a plasma that emits radiation, allowing for airspeed and density measurements with smaller, lighter, and less expensive lasers, and a sensor system to detect properties of the plasma for computing air data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If LIDAR systems are used to measure air data at high altitude, then air data measurement capability is improved, but system size, weight, and cost increase significantly
Solution Approach 1:
The patent changes the fundamental measurement parameter from detecting reflected laser light (LIDAR) to detecting plasma emission and absorption characteristics. By tuning the laser wavelength to match specific molecular absorption lines and exploiting plasma emission at these wavelengths, the system achieves sensitive air data measurement with much lower laser power requirements, thereby reducing system weight
Solution Approach 2:
The patent replaces the mechanical/optical LIDAR detection system with a plasma-based detection system. Instead of measuring reflected light from neutral air molecules, the system creates plasma and measures its emission and absorption properties, which are far more sensitive and require less laser power, thus reducing system weight and complexity
2Device complexity
If pitot tubes are used for air data measurement, then system simplicity is improved, but reliability deteriorates due to icing, insects, and bird strikes
Solution Approach 1:
The patent replaces the mechanical pitot tube system with an optical/plasma-based measurement system. By creating plasma in the air stream and measuring its emission and absorption characteristics, the system obtains air data without any physical protruding elements, eliminating susceptibility to icing, insect accumulation, and bird strikes while maintaining measurement accuracy
3Measurement precision
If conventional lasers are used for high-altitude LIDAR, then detection capability is improved, but laser size, weight, and cost increase
Solution Approach 1:
The patent changes the detection mechanism from measuring reflected light intensity to measuring plasma emission and absorption at specific wavelengths. This parameter change allows the use of lower-power, smaller, lighter lasers because the plasma emission provides a strong signal that does not require high laser power to generate, thereby reducing laser weight while maintaining detection capability
Solution Approach 2:
The patent introduces plasma as an intermediary between the laser and the detection system. The plasma absorbs laser energy and re-emits at characteristic wavelengths, providing a amplified signal that can be detected with smaller, lighter lasers. This intermediary mechanism allows sensitive detection with reduced laser power requirements, thus reducing laser weight
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 approach provides reliable air data measurement at hypersonic speeds with reduced equipment size, weight, and cost, and is less susceptible to environmental damage, enabling 3D orientation calculations and operation in icing conditions.
Implementation Method 1
emitting, by a laser disposed on the aircraft, laser light into air outside the aircraft, the laser tuned to induce a laser-induced plasma channel (LIPC) in the air
Implementation Method 2
a laser-induced plasma channel (LIPC) in the air. The method also includes sensing, by a sensor system disposed on the aircraft, at least one property of the LIPC
Data Source
AI summary
A method of measuring air data of an aircraft is provided. The method includes emitting, by a laser disposed on the aircraft, laser light into air outside the aircraft, the laser tuned to induce a laser-induced plasma channel (LIPC) in the air. The method also includes sensing, by a sensor system disposed on the aircraft, at least one property of the LIPC. The method further includes computing, by a computing device disposed on the aircraft, the air data of the aircraft based on the at least one property of the LIPC.