Design of Airborne Strapdown Inertial Navigation System Based on DSP Structure

Abstract

An airborne strapdown inertial navigation system based on DSP is introduced. The TMS320F28335 and TMS320C6416 DSP chips of TI Company are used as the core components of the system, and the CPLD technique combined with the dual DSP structure of strapdown control and solution are used to realize logic circuit of the system. From the analysis of the hardware, software and overall design, the scheme can match the characteristics of the strapdown inertial navigation system, such as fast speed, high accuracy and good stability. Introduction Inertial navigation system (INS) is an autonomous navigation system which developed at the beginning of the 20th century [1]. It depends on neither the external navigation station and information nor the spreading radio. INS has strong concealment and anti-jamming ability, which can provide real-time navigation parameters. The application of INS is divided into two types: mechanical platform inertial navigation system and strapdown inertial navigation system. Strapdown inertial navigation system does not need entity platform. The gyro and accelerometer are connected on the carrier directly. By the replace of inertial platform to computer, the INS is also referred to as mathematical platform. The main functions of mathematical platform are coordinate transform matrix and the attitude angle calculation [2]. The strapdown inertial navigation system has advantages such as simple structure, small size, light quality, low cost, fast initial alignment etc, and it has been widely used as the airborne navigation equipment [3]. Presently most strapdown inertial navigation systems adopt general computer core and architecture. However the general microprocessor of von Neumann structure has disadvantages such as slow data processing, large volume, high power consumption, complex circuit and low reliability, which is unable to meet the requirements of strapdown inertial navigation system on the miniaturization, high precision and real-time requirements [4]. The real-time information processing system based on digital signal processor (DSP) has the features as high-speed, stable, full digital. It has modified Harvard architecture, advanced multi bus and multi pipeline mechanism, dedicated hardware multiplier and efficient instruction set, and it is easy to be embedded in every kind of signal filtering and information integration algorithms with well real-time characteristic [5]. With the performance increase of DSP, the research and development of the DSP based airborne strapdown inertial navigation system has attracted many attentions [6]. The overall structure of the system The strapdown inertial navigation system is composed of micro inertial measurement group, data acquisition and preprocessing unit, navigation solution unit and communication unit. The system structure is shown in Figure 1. The hardware circuit design and software design are introduced in this section. 4th International Conference on Computer, Mechatronics, Control and Electronic Engineering (ICCMCEE 2015) © 2015. The authors Published by Atlantis Press 97