def search(x,prn):
fs = 8192000.0
n = 8192 # 1 ms coherent integration
incr = float(b1i.code_length)/n
c = b1i.code(prn,0,0,incr,n) # obtain samples of the B1I code
c = fft.fft(np.concatenate((c,np.zeros(n))))
m_metric,m_code,m_doppler = 0,0,0
for doppler in np.arange(-5000,5000,200): # doppler bins
q = np.zeros(2*n)
w = nco.nco(-doppler/fs,0,2*n)
for block in range(80): # 20 incoherent sums
b = x[(block*n):((block+2)*n)]
b = b*w
r = fft.ifft(c*np.conj(fft.fft(b)))
q = q + np.absolute(r)
idx = np.argmax(q)
if q[idx]>m_metric:
m_metric = q[idx]
m_code = b1i.code_length*(float(idx)/n)
m_doppler = doppler
m_code = m_code%b1i.code_length
return m_metric,m_code,m_doppler
def search(x, prn):
fs = 8192000.0
n = 8192 # 1 ms coherent integration
incr = float(b1i.code_length) / n
c = b1i.code(prn, 0, 0, incr, n) # obtain samples of the B1I code
c = fft.fft(np.concatenate((c, np.zeros(n))))
m_metric, m_code, m_doppler = 0, 0, 0
for doppler in np.arange(-7000, 7000, 200): # doppler bins
q = np.zeros(2 * n)
w = nco.nco(-doppler / fs, 0, 2 * n)
for block in range(80): # 20 incoherent sums
b = x[(block * n):((block + 2) * n)]
b = b * w
r = fft.ifft(c * np.conj(fft.fft(b)))
q = q + np.absolute(r)
idx = np.argmax(q)
if q[idx] > m_metric:
m_metric = q[idx]
m_code = b1i.code_length * (float(idx) / n)
m_doppler = doppler
m_code = m_code % b1i.code_length
return m_metric, m_code, m_doppler