The Research And Design Of The Carrier Attitude Anglede Coding Algorithm Based On FPGA

The attitude of carrier in space is important information about the people to ascertain what status of the carrier in space. It’s a convenient way to ascertain the carrier’s movement posture and direction. The decoding algorithm is one of the core technology that the inertial navigation system using to do a precision navigation. Traditional algorithm is inseparable form the large amount of matrix operations, when implement on hardware, the algorithm is very complex with a large amount of calculation. In this paper, based on the research of the space vehicle attitude algorithm, propose using Coordinate Rotation (CORDIC) algorithm to solve the attitude angle, simplify the algorithm. At the same time, use the FPGA technology effectively to speed up the array of floating point arithmetic, it designed and implemented a high speed and high precision system to calculate the attitude angle on FPGA.At first, in the paper, we detailed study three traditional decoding algorithms of the attitude angle (Direction cosine method and Euler method and Quaternion method). And analysis the advantages and disadvantages of each algorithm, compared with CORDIC algorithm, propose using CORDIC algorithm to solve attitude angle.Secondly, mainly analysis the single precision floating point number stored format in the computer. Propose the rules of the addition, subtraction, multiplication and division algorithm, those based on single precision floating point numbers operation and the transformation rules about the integer to single precision floating point number. Focus on analysis the precision and data bits wide in the process of the calculation, according control the floating point number index to control the data accuracy, designed a high speed, high precision of attitude angle calculating system.Thirdly, carry on the optimization to the traditional CORDIC algorithm, adopts single precision floating point numbers operation directly, remove ROM look-up table procedure to reduce the consumption about the resource. Through the appropriate trade-off in terms of iteration times and increase the number of revolution, making the direct solution of the optimization CORDIC algorithm can cover the whole attitude angle apace, namely the whole circumference of360.Finally, the optimized CORDIC algorithm is applied to solve attitude Angle and implementation on FPGA hardware platform. Use Verilog HDL language to design the whole system, then successfully simulation and adaptation the program, get a good results on the speed, accuracy and footprint.