Development of a Single-Channel Direction Finding Algorithm
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- Điều hướng trang này:
- Classical DF Algorithms
| X=a 5(t) (2.6)
This approach can be scaled up to construct a received signal that is the combination of multiple signals. By creating a matrix S which represents the finite number of incident signals, D, as its rows: 50(t) (2.7) 5d-1(t) and a second MxD matrix A: A [ a (ộ0, 50) ■■■ a (ộ D-1. 5 D-1)] (2.8) where a (ộd. 5d) is the array manifold vector for the d-th received signal, we can then express the received signal as: X = AS + N (2.9) where X is essentially the linear combination of D signals given by equation 6 and N is a noise vector representing AWGN in the received signal path that is assumed to be independent for each antenna and receiver path. This multiple signal model will be revisited in Chapter 7 during the discussion of the PLL algorithm's performance in the presence of multipath. Classical DF Algorithms Watson-Watt Algorithm The Watson-Watt algorithm [6] is an old amplitude-based analog DF algorithm that can use either two orthogonally oriented loop or Adcock pair antennas. In an Adcock pair, the vector difference of the voltage outputs from the two antennas is taken to provide a single output from the pair. This difference operation effectively merges the circular gain patterns of the two discrete antennas into a figure-8 pattern with maximum gain along the baseline of the pair and a null along the perpendicular to the baseline midpoint. The perpendicular arrangement of two such pairs is shown in Figure 2.2 with the first pair antennas labeled AN and AS (for North and South antennas) and the second pair labeled AE and AW. This same gain pattern can be achieved with the use of two crossed loop antennas as the typical gain pattern for a loop antenna is a figure-8 with the gain pattern of the north-south pair shown as the solid gray line and the gain pattern of the east-west pair shown by the dashed black line. In order to produce the DOA estimate, the voltage output from both antenna pairs (in the case of two Adcock pairs) is compared. The two outputs can be expressed as: 1.1Project Equipment Description 3 1.1.1Software Introduction 3 1.1.2Hardware Introduction 3 1.2Thesis Description 3 Chapter 2 4 2.1Direction Finding Fundamentals 5 2.1.1Basic Assumptions 5 2.1.2The Received Signal Model 6 2.2Classical DF Algorithms 10 2.2.1Watson-Watt Algorithm 10 tải về 2.23 Mb. Chia sẻ với bạn bè của bạn:
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