Dual-Direction Laser Speed Detection for Altitude Variations
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Solution Overview
Problem
Existing speed detection methods for vehicles, such as pitot tubes and LIDAR sensors, face challenges like environmental susceptibility and reduced performance due to varying particle densities at different altitudes, which affect the accuracy and reliability of speed measurement.
Innovation Solution
A method and system that emits laser beams in different directions from a vehicle, generating sets of backscatter light with frequency shifts, which are interfered to produce beat frequencies, allowing for accurate speed determination using these frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pitot tube is used to detect speed, then speed detection is achieved, but the sensor is susceptible to environmental conditions such as bird strikes and ice formation
Solution Approach 1:
The patent replaces the mechanical pitot tube sensor with an optical LIDAR-based speed detection system. Instead of using a physical tube that protrudes into the airflow and is vulnerable to environmental damage, the invention uses laser beams to measure the Doppler shift of backscatter light from atmospheric particles, thereby eliminating the mechanical sensor and its susceptibility to bird strikes, ice formation, and other environmental harmful factors.
2Ease of operation
If a LIDAR sensor is used to detect airspeed, then non-contact measurement is achieved, but performance is reduced due to varying particle densities at different altitudes
Solution Approach 1:
The patent segments the atmospheric backscatter signal into multiple frequency components by emitting laser beams in multiple directions and detecting the Doppler shift of backscatter light from particles at different locations. By analyzing the frequency spectrum of the combined backscatter signals, the system can accurately determine airspeed even when particle density varies with altitude, as each directional beam samples different atmospheric regions.
Solution Approach 2:
The patent transitions from single-direction to multi-directional laser beam emission, adding spatial dimensionality to the measurement. By emitting laser beams in multiple directions and combining the backscatter signals, the system creates a more robust measurement that is less sensitive to vertical particle density variations, effectively using spatial diversity to overcome the limitation of single-point sampling at varying altitudes.
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 enhances speed detection accuracy and reliability by increasing frequency shifts and overcoming the limitations of particle density variations at different altitudes, providing improved performance across various flight elevations.
Implementation Method 1
a light detection and ranging (LIDAR) sensor. With a LIDAR sensor, a laser beam is transmitted into the air and backscatter generated in response to the laser beam is detected
Implementation Method 2
The airspeed of the aircraft can be determined by comparing the frequency of the laser beam to the frequency in the backscatter. This shift in frequency can be used to calculate the speed of the aircraft
Implementation Method 3
A first backscatter light and a second backscatter light are detected. The first backscatter light having a positive frequency shift is generated in response to emitting the first laser beam and a second backscatter light having a negative frequency shift is generated in response to emitting the second laser beam. The first backscatter light is interfered with the second backscatter light.
Data Source
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AI summary
A method, apparatus, and system detect a speed of a vehicle. Laser beams are emitted into an atmosphere from the vehicle. The laser beams are emitted in different directions from the vehicle. Sets of backscatter light are generated in response to transmitting the laser beams into the atmosphere from the vehicle. The sets of backscatter light have frequency shifts relative to the frequency of the laser beams. A set of beat frequencies from interfering the sets of backscatter light with each other is measure. The speed of the vehicle is determined using the set of beat frequencies.