针对同轴偏场三反射镜系统,提出了一种宽视场波前误差检测方法.通过3个视场的波前误差检测,得到相应视场像差的Zernike多项式系数,利用该Zernike多项式系数减去设计误差后,随视场的变化为二次曲线,通过抛物线插值即可得到任一视场的Zernike多项式系数.仿真研究了Zernike多项式系数随视场的变化以及拟合精度等问题.仿真结果表明:对于原始设计误差,其Zernike系数随视场的变化需要用3次或4次曲线拟合;对于由主镜面形误差、次镜位置误差、次镜面形误差和三镜面形误差等引起的各视场波前误差,其Zernike系数随视场的变化可用直线或2次曲线拟合.通过事先存贮设计误差,仅需3个波前传感器即可实现全视场波前误差估计.Zernike系数估计误差在10-5量级.

A method to estimate the wavefront errors of a wide-field line-scan space camera with a coaxial three-mirror anastigmatic optical system is proposed.Zernike polynomial coefficients of 3 fields are obtained through 3 wavefront sensors,after subtracting the design aberrations,the Zernike polynomial coefficients varies with field along a parabolic curve,then Zernike polynomial coefficients of any field can be estimated by interpolating.That the Zernike polynomial coefficient varies with field and the accuracy of the fitting is studied by simulations.Simulations show that the Zernike coefficients of the design error vary with field along a cubic curve or quartic curve.The Zernike coefficients of the wavefront error caused by surface error of the primary mirror,position error of the second mirror,surface error of the second mirror,and surface error of the third mirror vary with field along a line or parabolic curve.So by storing the design errors,only 3 wavefront sensors are needed to estimate the wavefront error of any field.Estimation error of the Zernike coefficients is in the order of 10-5.