Research On Mechanism Of Optoelectronic Cooperative Target For Aerial Pose Measurement

The methods that can be taken to measure the relative pose of two aircrafts include INS technology,GPS technology,microwave radar technology,laser radar technology and optoelectronic pose measurement technology and so on.And optoelectronic pose measurement system has important applications in close measurement phase for its high measuring accuracy and measuring speed.The optoelectronic pose measurement system generally consists of cameras,signal processing subsystem and target,and target includes cooperative target and non-cooperative target.Cooperative target has become the main type of optoelectronic pose measurement system as it has higher extraction accuracy and lower extraction difficulty than non-cooperative target.Obtaining high SNR images of the target is the precondition of pose solving,but for aerial pose measurement system,there are two factors that affect the image quality must be taken into consideration.First is stray light interferences mainly caused by sunlight,second is atmospheric attenuation under complicated weather conditions.Currently there are enough researches on anti-interference methods for the space pose measurement system,the generally method is first analyzing the sunlight effects by blackbody radiation law and Planck formula,and then selecting infrared light-emitting devices and filter to suppress stray lights.But for aerial pose measurement system which works inside the atmosphere,firstly due to the effects of the atmosphere,the distribution of sunlight intensity becomes different from the result of Planck formula,it does not drop strictly when the wavelength increases.Secondly sky background becomes the imaging background,but the distribution of sky background luminance is very complex,it has a strong relationship with the sun's position,the line-of-sight direction and the cleanliness of the atmosphere.The target-background contrast may differ greatly under different conditions.Furthermore,the atmospheric attenuation brings down the atmospheric transmittance,and the atmospheric transmittance has a great relationship with wavelength,transmission distance and atmospheric conditions.It is very important to analyze these factors for aerial pose measurement system.This paper analyzed the factors that influence the atmospheric transmittance and distribution of sky background luminance,and calculated the atmospheric transmittance and distribution of sky background luminance under a variety of atmospheric conditions by MODTRAN.On this basis,selecting high power infrared LEDs working at 740 nm as the light-emitting devices of the optoelectronic cooperative target,and combing the narrow-band filter and anti-interference algorithm,the optoelectronic cooperative target got a good anti-interference ability and environmental adaptability.