摘要:

The time extents of pulse compression (spread-spectrum) signals are often so long that the signals may overlap, for example the case of radar targets that are close together. The effect of this overlapping is considered in a general versatile computer simulation for the cases of steady strong and weak signals in a Weibull clutter environment. The signal reported in the paper is a 39-bit combined Barker word which when compressed in a 150-bit transversal filter of the minimum square error type will give −40 dB temporal sidelobes. The results demonstrate quantitatively that, in the case of identical radial velocities, signal overlap is strongly detrimental to signal detection. Typically, if there are two signals (one strong and the other weaker) in a clutter environment then, if the uncompressed weak signal/clutter ratio is −3 dB and if the strong-signal/ weak-signal ratio is 9 dB, both signals may be detected until there is an overlap of about 50%. At greater overlap the compressed weak signal cannot be identified in the clutter.

DOI:10.1049/ip-f-1.1983.0087

出版商:IEE    

年代:1983

数据来源: IET

摘要:

The advantages of using digital convolution to implement a particular pulse compression radar filter are outlined. Using the bandwidth of the given filter, a simple calculation of the required computation rate indicates that considerable parallel computation would be necessary using existing integrated circuits. Some methods of computing the DFT are given and the FFT algorithm is chosen since its regular structure and in-place computation facilitate parallel computation. A description of the parallelism in the radix-2 pipeline FFT is presented, and it is shown that to obtain the required processing rate further parallel processing is necessary. By computingnbutterflies in parallel at each stage of the FFT a family of parallel pipeline FFT processors are developed. Using the new architectures allows an increase in the processing speed while retaining the simple structure of the pipeline FFT. It is shown that for each value ofNandnthere are four canonic forms of equivalent computational complexity, but with different structures. The four forms arise from the two types of DIT FFT algorithm and the two methods of selecting the order in which the butterflies are computed. The connection between the FFT algorithm and the binarym-cube array is given, and is used to show by an example how the architectures presented fit between the normal pipeline FFT and the array processor in the amount of parallel computation involved. The radix-4 pipeline FFT is described and it is shown that this structure can also be paralleled in a similar way to the radix-2 pipeline FFT. The amount of hardware required to implement digital convolution using these architectures is discussed and examples are given. The balance between logic speed and integration density and the problems of interconnecting the computational elements are also discussed.

DOI:10.1049/ip-f-1.1983.0088

出版商:IEE    

年代:1983

数据来源: IET

摘要:

The moving-target detector digital radar processor is based on a bank of FIR Doppler filters for clutter rejection and pulse integration. The system requirements call for unconventional filter design methods. In the design trade-off, the choice of the number of bits to represent the weights plays an important role, since filtering performance can be significantly affected with less than 8-bit weights.

DOI:10.1049/ip-f-1.1983.0089

出版商:IEE    

年代:1983

数据来源: IET