Page 438 - Fundamentals of Radar Signal Processing

PRFs correspond to N = 4, N1 = 5, N = 7 range cells. A single target is
2
0
detected in the first range bin on the first PRF, the fourth range bin on PRF
#2, and the second range bin on PRF #3; i.e., n = 1, n =4, n = 2.
a 1
a 0
a 2
Assume the radar sensitivity is such that it could possibly detect targets out
to the 15th range bin. Use the coincidence algorithm to determine the true
range bin number for this target.

27. Repeat the previous problem using the Chinese Remainder Theorem
approach.

28. Again consider range ambiguity resolution using three PRFs. Suppose the
three PRFs correspond to N = 3, N = 4, and N = 5 range cells. Two
1
0
2
targets are detected in each PRF: in range bins 1 and 2 of the first PRF,
bins 1 and 4 of the second PRF, and bins 2 and 4 of the third PRF. Assume
the radar sensitivity is such that it could possibly detect targets out to the
25th range bin. How many targets will be reported by the coincidence
algorithm, and in which range bins?

29. Now assume that in the previous problem, one false alarm occurs on the
third PRF in range bin #3. How many targets will be reported by the
coincidence algorithm, and in which range bins?

30. Now suppose that in Prob. 28, the target in range bin #4 on the third PRF is
not detected (a missed detection). How many targets will be reported by

the coincidence algorithm, and in which range bins?

31. Finally, suppose only the second and third PRFs in problem 28 are used.
How many targets will be reported by the coincidence algorithm, and in
which range bins?

32. Suppose a radar has a pulse length of t = 10 μs and a PRF of 10 kHz.
Assume that the clutter observed by the radar has a two-sided spectral
width of 1 kHz (i.e., the clutter spectrum occupies the range from –500 to
+500 Hz). Sketch the blind zone map for these operating conditions. For
the vertical axis, use time in seconds from 0 to 400 μs; for the horizontal

axis, use Doppler frequency in hertz from –10,000 to +10,000 Hz.
33. A weather radar has a PRF of 2 kHz. Using a series of 50 samples of data
from a particular range bin and look direction, the following values of the

autocorrelation function are computed: s [0] = 50, s [1] = 30 exp(jp/3).
y
y
Use the pulse-pair processing (PPP) time domain method to compute the
estimated mean frequency of the echo in hertz.

34. Continuing with the same weather radar, the mean Doppler shift is now
removed from the data to obtain a new sequence y´[m] with autocorrelation
lags s [0] = 50, s [1] = 30. Use the PPP time domain method to compute
y′
y′
the estimated spectral width of the echo in hertz. Use the version of the
spectral width estimator that contains the ln(·) function. Remember that