The invention relates to a position detection method of a large-calibre
millimetre wave / sub-
millimetre wave telescope control system, comprising the following steps that: (1), an upper computer sends an instruction to a DSP (
Digital Signal Processor) module; (2), coarse and fine channels of a double-channel multi-polar
rotary transformer output a
signal through a
digital converter, and, after being subjected to level conversion, the signals are transmitted to the DSP module; (3), the DSP module calculates an absolute mechanical position
signal of an arc motor, so that the
closed loop of the arc motor is realized; (4), the DSP module converts the
signal into an electrical angle, so that the current
closed loop of the arc motor in
vector control is realized; (5), the interior of the DSP module converts the signal obtained in the step (2) into A, B and Z signals in the form of coder through a
software; (6), the A, B and Z signals are output through an IO interface of a DSP and sent to the DSP module through a serial interface after a CPLD (
Complex Programmable Logic Device) module counts and judges the direction; and (7), the DSP module calculates the rotation speed and the steering direction of a motor according to a count value obtained in the step (6), so that the speed
closed loop of the motor is realized. The position detection method disclosed by the invention can realize low-speed
angular velocity of 1'' / s and high-speed
angular velocity of 12 DEG per s, without the low-speed creeping phenomenon.