基于CORDIC改进算法的反正切函数在FPGA中的实现

摘要

针对基于FPGA的分布式导航系统中涉及大量的三角函数运算，而传统的查找表或差值法计算，在精度、运算速度方面不能兼得，且占用资源多，文中提出了基于CORDIC算法的反正切函数计算的改进方法与流水线结构的实现方法，使用VHDL硬件描述语言进行编程实现，在Quartus II 9.0中对算法进行功能仿真，最后通过Altera公司的FPGA Cyclone II系列芯片进行了具体验证。验证结果表明，针对累加器中因截尾而产生的误差所作的算法改进，显著地提高了算法精度，而且运算速度快。%In the light of a large number of trigonometric function calculations in the distributed navigation systems based on FPGA,while with the traditional looking-up-table or differential methods,the calculation accuracy and speed can not be got at the same time,taking up more resources,present the improved measures and pipeline structure of arc-tangent function based on CORDIC algorithm,use VHDL to program,and by using the Quartus II 9. 0 the function simulation can be got,finally on the Altera FPGA chip the algorithm is tested. The results show that,truncation error generated by the accumulator are reduced significantly,and the algorithm accuracy is improved,the computing speed is very fast.