Study of Continuous Discrete Convolution Algorithm on Digital Signal Processor

Abstract

Continuous discrete convolution is an important tool in modern robot navigation systems due to its ability to process signals efficiently. Modern robot navigation systems use various filtering and data integration techniques such as the Kalman filter or the Simultaneous Localisation and Mapping (SLAM) algorithm. However, continuous discrete convolution complements these approaches. A continuous discrete convolution algorithm based on Fast Fourier Transform (FFT) has been developed, which allows processing large amounts of data in real time, which is critical for robot navigation. Since the signals from the avalanche photodiode are continuously converted using an ADC and written to a buffer, they are time series. Continuous discrete convolution, which takes into account the time sequence of the data, is well suited for an analysing such data and extracting useful information from it. A continuous discrete convolution algorithm on the TMS320F28377D processor, implemented on the basis of the FFT of laser range finder time series and fan beacon laser systems, has been investigated. The peculiarity of the discrete convolution implementation is its real-time operation for searching beacon laser signals with a given frequency. The program implements simultaneous conversion of the analogue signal of the optical receiver using the built-in ADC, recording of the digital signal into one of two buffers and parallel calculations in the other buffer of the fast convolution on the processor and coprocessor TMS320F28377D in assembly language. Two direct memory access DMA modules, the CLA accelerator module of the TMS320F28377D processor are used to increase the processing speed. The correlation function calculated as a result of convolution of the initial signal with a reference signal of rectangular form with a given frequency is obtained. The maximum of the calculated correlation function shows the time delay between the beginning of beacon pulse transmission and the time of reception at the photodiode. This delay time shows the azimuth to the beacon.