The Application Of DSP To The North-Seeking Instrument System

In the life and practice of people, the information of geographical orientation is essential. So it is instructive to do research on the orientational and directional instrument. People have always been making great efforts to explorethe technology of orientation and direction for long time. The occurrence andapplication of the inertia and computer control make it possible to devise anddevelop the independently and precisely orientational instrument.Platform system, as independent and highly precise navigation equipment, has been widely used in all kinds of ships and submarines. However, because its north-seeking principle is the compass principle based on movable mount, the time of seeking north is too long . This paper introduces an analytic method of quick north seeker ,whose principle is to use gyro to sense the component value of the angle-rate of the rotation of the earth.. In term of the principle the northern azimuth angle (between the referenced shaft of carrier and actual north angle) can be measured. By means of this method, ships can only spend 3-5 minutes in seeking for the north at the state of berthing. The north-seeking system equipped in chariots is the orientational instrument based on this elementary principle.This system applies two-shaft and two-position north-seeking scheme, conbines highly stable and accurately directional machine, and builds the corresponding theory of error analysis and method of error modification , which makes the precision of the north seeker improved well. Besides this ,the system utilizes computer to control north-seeking process, and implements lots of compensatory schemes, so the precision of north seeker is increased more .DSP , as an special digital signal processor, has high operation speed and precision, and the TMS320C31 DSP used in the paper has the capacity of float point operation. All of the characteristics make the operation of complicated mathematics in north-seeking system more easy. Using C31 DSP as core, this paper designed and debugged the hardware and software which consists of data sampling, signal outputting and communication. The result is good.