FFT Splitting for Improved FPGA-Based Acquisition of GNSS Signals

Table 3

Comparison of the resources for the different algorithms using the Altera FFT for the L5, E5a, E5b, and E1 signals, considering time multiplexing.

Implementation	Logic usage	Memory usage	Multipliers usage
	(ALM)	(M20K)	(DSP blocks)
3-FFT solution (Figure 5(a))
Total	8760	1824	38
5-FFT solution (Figure 6)
Total	8274	792	38
Difference with 3-FFT solution	−486; (−5.5%)	−1032; (−56.6%)	0
Proposed 9-FFT solution (Figure 7)
Total	8805	484	46
Difference with 3-FFT solution	+45; (+0.5%)	−1340; (−73.5%)	+8; (+21.1%)
Difference with 5-FFT solution	+531; (+6.4%)	−308; (−38.9%)	+8; (+21.1%)
Proposed 15-FFT solution
Total	8645	286	52
Difference with 3-FFT solution	−115; (−1.3%)	−1538; (−84.3%)	+14; (+36.8%)
Difference with 5-FFT solution	+371; (+4.5%)	−506; (−63.9%)	+14; (+36.8%)