Study of Digital Discrete Fast High Order Bandpass Filter on TMS320F28377D Processor for Mobile Robot Navigation

A digital discrete high-order fast bandpass filter on the TMS320F28377D processor for mobile robot navigation is developed and investigated. The application of the developed band-pass filter in beacon laser navigation systems is proposed in order to increase the speed of mobile robot coordinate computation when solving the fast convolution problem. A fast convolution algorithm based on a digital continuous band-pass Butterworth filter, which is optimal in terms of minimum computation time, is presented. The developed 22-order Butterworth filter is implemented on a digital signal processor TMS320F28377D using a double buffer with parallel recording and processing of data from ADC. The peculiarity of the bandpass filter implementation is its real-time operation for searching signals of navigation beacon lasers in a given frequency band. Two DMA direct memory access modules, CLA accelerator module of the TMS320F28377D processor are used to increase the speed of data processing. The correlation function calculated as a result of convolution of the original signal with the reference signal of a given frequency and filtered by a low-pass filter using the moving average method was obtained. The maximum of the calculated correlation function shows the time delay between the beginning of the beacon pulse transmission and the reception time at the photodiode. This delay time shows the azimuth to the beacon. Laser beacon system (LSM) for robot navigation has the following advantages compared to radio equipment: lower range measurement error, small size of optical systems compared to the size of radar antennas, and high angle resolution due to the narrow beam of sounding radiation. High noise immunity of LSM, including to deliberate interference, allows solving navigation tasks in conditions of suppression of global navigation systems (such as GPS and GLONASS), when the means of autonomous navigation cannot fully provide data to the robot control system. The convolution execution time on the TMS320F28377D processor is 1.8 ms.