Arithmetic processing method and system in a wide velocity range flight velocity vector measurement system using a square truncated pyramid-shape five-hole pitot probe

摘要

An arithmetic processing method and system in a wide velocity range flight velocity vector measurement system using a square truncated pyramid-shape five-hole Pitot probe. Approximation equations that determine attack angle alpha and sideslip angle beta in the form of third-order equations concerning attack angle pressure coefficient Calpha and sideslip angle pressure coefficient Cbeta, which are known numbers, are expressed in the form of a polynomial equation concerning Mach number M, where the coefficients are obtained from a lookup table. Coefficient calculations in the polynomial equation, and attack angle a and sideslip angle beta, calculations may be performed as simple calculations by specifying and applying known numbers into the approximation equation without solving third-order equations, with calibration coefficients that form the basis of coefficient calculation with the polynomial equation first being stored in memory in advance as a table for each wide velocity range on the basis of wind tunnel testing. A Mach number may be calculated instantly from a lookup table by specifying Mach pressure coefficient CM and angle to airflow pressure coefficient Cgamma. Wide velocity range flight velocity vector measurement with a high update rate which is capable of real time response in flight control as demanded by aircraft is obtained.