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Table 1 Complexity evaluation of different FFT-based acquisition schemes

From: Reduced-complexity FFT-based method for Doppler estimation in GNSS receivers

Algorithm Number of FFTs Number of tested Average number Number of real
   Doppler values of IFFTs multiplications
    High CNR Low CNR High CNR Low CNR
Conventional FFT-based 2 41 20.5 41 32N+390C N 32N+780C N
EGS (1 ms) 2 41 1 25 36N+57C N 36N+441C N
EGS + BA (5 ms) 10 201 1 25 180N+217C N 180N+601C N
EGS + BA (10 ms) 20 401 1 25 360N+417C N 360N+801C N
EGS + BA (20 ms) 40 801 1 25 720N+817C N 720N+1,201C N
EGS + NCI (10 ms) 20 41 1 25 322N+57C N 322N+441C N
  1. N is the FFT length, and C is the number of searched PRN codes. In low CNR case, the PRN is absent or the detection probability is small.
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