Acoustic Warfare - Coherent Sampling of 8x8 Microphone Array

SAAB developed ”Acoustic Warfare” as a medium for experimenting with and demonstrating theconcept of Active Electronically Scanned Array (AESA) in a simpler and more easily accessibleway. It consists of an 8x8 microphone array and an Field-Programmable Gate Array (FPGA) usedto sample the microphones, as well as a computer used for analyzing the data. The purpose ofthis project was to investigate the possibility of replacing the hardware currently used for samplingthe audio with the Raspberry Pi 5 (RasPi5). The solution should make it cheaper, without havingto change or adjust any other components. This was done by implementing custom programsutilizing PIO assembly, which would allow the PIO state machines (SM) to generate the twodifferent clock signals on its General Purpose Input Output (GPIO), at 25.0 MHz, duty cycle 1/2 and 48.8 kHz, duty cycle 2/512 respectively. These were meant to control the sampling, and theresults of the initial tests showed that these signals were performing it correctly. Reading thedata proved to be possible, but the data processing as a whole remained incomplete due to timeconstraints. This meant that no testing of the whole system could be performed. However, theresults of this thesis suggest that with further development, the Raspberry Pi 5 should have thecapability to replace the FPGA in ”Acoustic Warfare”.