Research Article
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%) |
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