The workspace measurement and positioning system is a distributed measurement system based on the rotary laser scanning technology. The laser signals are always disturbed in the processes of generation from the transmitter, transmittance through the physical space and reception by the receiver, and simultaneously the measurement errors are introduced. The time signal error analysis method and the corresponding filtering technology are introduced, and the error components occurred in the measuring process are analyzed based on the laser signal timing principle. Meanwhile, the time series signals are preprocessed as well the time and frequency domain characteristics are analyzed based on the time series statistical theory. The common-mode errors are found existing in the time series data, and the principal component analysis method is adopted to eliminate them. The experimental results show that the noise amplitudes of different time series are reduced by 10% after principal component analysis filtering.