The position system which uses an inductosyn as a transducer can measure the angle and the length very accurately. Combining it with the computer constitutes the digital servo system with high precision. This instrument has been broadly used in astronomical navigation

missile controlling

satellite tracking

radar

disk storage

and almost all kinds of precision machine tools. If the position system works in static mode

the position error of the transducer will affect the positioning precision. However

once the inductosyn has been made

its position error is fixed

hence we can test its characteristic. In this paper

the inductosyn’s positional error is analysed

and from which the mathematical model describing the positional error is formed. The computer can automatically correct the positional error through its error characteristic

so that the system’s precision of the static positioning will be improved. This is performed by software. "The program for correcting the positional error" written in ALGOL-60 is presented. Because the method is applicable

in principle

to the multipolar rotary transformer

it will be able to make higher precision position system by use of lower precision transducer.When the position system works in dynamic mode （e. g. to measure the antenna’s azimuth）

as soon as the system has received the return from an object

the computer must immediately read the antenna’s azimuth for computing the coordinate of the object at the moment. Because of the delay in the course of tracking

a dynamic error is introduced to the system

and it affects the’ dynamic positioning precision of the radar. In this paper

a mathematical model describing the dynamic error is given. Based on this model

a method for testing the dynamic error is developed

which is easy to adopt from the engineering point of view. Also developed here is a new technique to improve the dynamic positioning precision by using a computer to correct the dynamic error. In conclusion

this paper gives the source program for correcting the dynamic error written in ALGOL-60

and the results of running the program on a NOVA machine.