Helicopter optical atmospheric data system

Abstract

The invention discloses a helicopter optical atmospheric data system, and aims to provide an atmospheric data system which is strong in anti-interference performance, high in precision and reliabilityand high in comprehensive detection resolving capability. The method is realized through the following technical scheme: based on a laser Doppler wind-finding radar detection principle, a sensor assembly emits laser to a sensed assembly. The sensor assembly emits laser to the atmosphere through multiple lenses. A scattering laser signal carrying optical axis airspeed information after interactionwith the atmosphere is received at the same time, the scattering laser signal is sent back to the sensor assembly to be processed, the sensor assembly calculates the optical axis airspeed and furtherobtains airspeed information of the helicopter, and the airspeed information comprises three-dimensional airspeed, an attack angle and a sideslip angle; meanwhile, the static pressure sensor measuresto obtain an atmospheric static pressure signal, and the static temperature sensor measures to obtain an atmospheric static temperature signal; and the sensor assembly performs data fusion on the obtained airspeed information, atmospheric static pressure information and atmospheric static temperature information, and directly calculates and outputs a complete helicopter three-axis atmospheric data signal.

Description

technical field [0001] The invention relates to an optical air data system for a helicopter. Background technique [0002] The entire development process of the air data system to the present has experienced the centralized air data system (CADS), the distributed air data system (DADS), the embedded air data system (FADS), the optical air data system (OADS) and the virtual air data system. The system (VADS) has five stages. The key symbols of the centralized air data system are the pitot and angle of attack / sideslip angle sensors placed outside the aircraft, the core of which is the central air data computer (referred to as the central air machine), and its basic airborne sensors The air around the fuselage is in direct contact with the atmospheric data system to provide information such as the temperature, air pressure, and direction of free flow (that is, the angle of attack and sideslip angle) of the external airflow. After the relevant data information is calculated, co...

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Problems solved by technology

When the pitot tube centralized air data system installed on the wing of the nose measures atmospheric information, the external atmospheric pressure sensed by the external pitot tube cannot be directly imported into the central atmospheric machine for calculation, and a long pressure transmission conduit is required. The structural characteristics lead to two obvious measurement defects: first, the longer pressure transmission device occupies a certain amount of space resources, and an additional deicing and heating device needs to be installed to prevent the space velocity tube from freezing and causing failure in severe cold weather; Second, there is a serious aerodynamic delay phenomenon during high-maneuvering flight, and the hysteresis of atmospheric information is relatively serious; in addition, all atmospheric parameters are transmitted to the central atmospheric engine for calculation, which puts very high demands on the performance and reliability of the atmospheric engine. requirements

Traditional air data systems have defects such as low measurement accuracy at low speeds, high requirements for installation locations, high calibration and maintenance costs, and poor performance in large maneuvers. These shortcomings have gradually failed to meet the application requirements of current or next-generation aircraft.

Similar to the air data system of fixed-wing aircraft, the pitot tube is used to sense the total pressure and static pressure of the helicopter during flight, and combined with the angle of attack sensor, sideslip angle sensor and static temperature sensor to realize the total pressure, static pressure, angle of attack, Direct measurement of sideslip angle and static temperature, and then use the fixed calculation and correction methods in the air data computer to complete the settlement and correction of air data. This air data system has the following problems: 1) Pitot, angle of attack sensor And the sideslip angle sensor needs to be installed in the position where the disturbance of the fuselage is small and the airflow is stable, and there is a shortcoming of large error between the measured atmospheric parameters and the real value; 2) Pitot, angle of attack sensor and sideslip angle sensor have Processing error and installation error, there are deviations between pressure and angle measurement values ​​and ideal values; 3) The characteristics of avoiding radar wave stealth, infrared stealth, laser stealth and image stealth are poor, and it is difficult to achieve stealth performance mainly relying on its shape; 4) The output speed parameters only have transverse true speed, no longitudinal true speed and vertical true speed

The working principle of the traditional air data system determines that it cannot provide weather warning when the helicopter is flying at ultra-low altitude in sea, mountainous and hilly areas, and hovering, which brings safety hazards to the helicopter

Moreover, the uncertainty of atmospheric temperature will bring random errors and systematic deviations to the detection of atmospheric pressure, so the traditional three-axis air data system cannot guarantee the measurement accuracy of atmospheric parameters at low speeds.

These problems are caused by the conflict between the flight principle of the helicopter and the measurement principle of the atmospheric machine, and any improvement to the existing air data system is difficult to solve fundamentally

And with the rapid development of new models, traditional air data systems are gradually unable to meet the new requirements of future aircraft for speed, altitude, overload, agility, and long endurance.

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