How to get phase information from CIR for PDOA application

For our bachelor thesis, we are developing an AOA estimation system for Leica Geosystems/Hexagon using two DW1000 as anchors and one as a transmitter, to which the angle shall be estimated. The tests with a TDOA based approach did not hold up to our angle accuracy specifications. Because of that we want to try out a PDOA and later a TDOA/PDOA hybrid approach. We based this on the decawave paper “Angle of Arrival Estimation Using Decawave DW1000 Integrated Circuits”. To calculate the AOA we therefore need the first path phase/angles of the two receivers, as well as the phase/angles of both their SFD’s. The further calculation is then described in the paper. Now we have some questions about getting this information out of the CIR:

  • How should decimal indexes be interpreted for the fp_index?
  • How do we get the CIR index of the SFD, to get that phase information?