辐射定标是通过定标器、热带雨林等已知雷达散射截面积的定标设备，获取定标参数，进而计算整幅图中每个单元的散射截面积。未经定标的SAR系统不仅系统稳定性差，测量重复率差，而且其图像无法精确地反映出来实际地物的散射特性。这将直接影响到定量遥感工作的顺利完成。故对SAR系统进行定标势在必行。 文章就SAR辐射定标技术问题展开研究，首先研究了基于均匀分布目标的天线方向图测试技术。主要在IDL环境下，采用平差方法剔除定标场地中非均匀地物，从而提高SAR图像目标的识别能力，并应用最小二乘方法拟合天线方向图。同时，采用Envi软件进行天线方向图测量。将两种方法结果与实测值进行比较，得出基于IDL均匀分布目标的测量方法更接近于实测值的结论。 其次详细研究常用四类角反射器微波反射特性，并从制作工艺误差切入，详细的分析了不同加工误差对二面角角反射器及三角锥形角反射器影响。模拟结果表明：相比较其他影响因素，夹角及不平整度对角反射器雷达散射截面积影响程度较大。 最后，详细的分析定标常数计算中的两种方法（积分法与峰值法）的优缺点并通过实验数据评价其定标精度。 对上述的技术及相关结论，文章采用Terra-SAR数据及X波段机载SAR数据，进行实验验证与分析，得出以下几点结论：（1）在定标常数计算过程中，积分法较峰值法更为稳定。（2）在定标设备方面，三角形角反射器相比正方形角反射器、扇形角反射器定标结果更稳定。（3）机载SAR定标虽然受到飞行平台稳定性的影响，但在单次的实验中依然取得了较高稳定度的结果。

The known radar cross section (corner reflector, tropical rainforests) of calibration equipment are used to get the calibration parameters and calculate the whole image of the scattering cross-sectional area of each cell, this called radiometric calibration. The SAR system without calibration not only owns unstable system but also has a poor measurement repetition rate. And its image also can’t be accurately reflected the actual feature of scattering properties. These weaknesses will directly affect the successful completion of the quantitative remote sensing work. So the calibration of SAR system calibration is imperative. The article studies the SAR radiometric calibration techniques. Firstly, the based on the uniformly distributed target antenna pattern measurement technology was researched. The method which is worked in IDL uses the adjustment idea to remove non-uniform surface features so that we can quickly find the objects in SAR images. Then, the paper applied the method of least squares fitting antenna pattern. The paper also measures the antenna pattern by Envi software. Compared with true values, the IDL method is more close to the true values than the Envi method. Secondly, the commonly four types of corner reflector’s microwave reflection characteristics were studied. Then to the different manufacturing error, the article analyzes the influence of dihedral angle corner reflector and the triangle angle corner reflector. The simulation results show that: the angle and the not flatness make a bigger influence than the other factors. Finally, the article analyzes the advantages and disadvantages of two kinds of calibration constant calculation methods and evaluates calibration accuracy of the integral method and the peak method using experimental data. For the above-mentioned technology and the related conclusion, the article uses the Terra-SAR data and X-band airborne SAR data to do experiment and get the following conclusions: 1.The calibration results were also influenced by different methods. The integration method was more stable than the peak method. 2.The experiments illustrate that the calibration results were effected by different corner reflectors. Compared with square trihedral corner reflector, fan corner reflector, the triangular trihedral corner reflector was more stable. 3.The results show that although airborne SAR calibration was influenced by flight stability of the platform, it could achieve high calibration accuracy.