Due to the excessive cost of 360° "multiple-transmitter and multiple-receiving " near field measurement in practical engineering applications, a truncated angular near field measurement method with a given accuracy requirement is proposed in this paper by analyzing the influence of the near-field scattering characteristics and the near-to-far field transformation on the RCS to greatly reduce the angular range of near-field antennas. In addition, it is often necessary to focus on components with strong scattering echoes while analyzing and diagnosing the local RCS. Therefore, an engineering-oriented near-field measurement method is proposed in this paper to achieve local RCS diagnoses of the targets. It includes two scanning modes, an arc array and a linear array, to achieve the goal of quickly performing local RCS analyses and diagnoses of coupled scattering targets through near-field testing. Regardless of the cost of the test site, the operability of the test system, and the efficiency of the work, this method provides a new technique for RCS measurement of stealth targets and has important research significance in weapon engineering test phases.

Because of the distortion of scatter pattern when measuring multiple-scattering targets in the condition of not satisfying the far-field condition, existing measurements are not favorable. We present a novel algorithm to research near-field to far-field transformation (NFFFT) for multiple-scattering targets. This paper introduces the method of NFFFT using “multiple emission multiple reception” and then chooses a dihedral angle, which has multiple-scattering structure to simulate. The results show a good agreement with the far-field radar cross section (RCS) pattern. Taking into account the feasibility of design, the cost of system, and other limitations in practical application, the bistatic measurement system with a full 360° is obviously hard to achieve. In the bandwidth-limited scattering field, we give the rule of angular truncation based on the transfer function for reducing receiving region. To make the conclusion more reliable, simulations should be set in different parameters, concluding testing frequencies, target size and measuring distance, to observe their effects on the receiving region. We get the mean error of different receiving region by comparing the results of NFFFT and far-field RCS. As a result, a principle for choosing a proper receiving region, say angular truncation, is summarized for multiple-scattering targets, with mean errors 0.5 dB below the full 360° results near the center of far-field pattern.

In the real world, the sparsity of signal is always unknown, making it challenging to determine the appropriate iteration stopping criteria and measurement