A review of spatial targeting methods of payment for ecosystem services

Payments for Ecosystem Services(PES)have been studied extensively over the past decade as an important policy tool for coordinating ecological protection and regional socioeconomic development.One of the greatest challenges of PES implementation is to understand where to pay,i.e.,spatial targeting,which can directly impact PES effectiveness and efficiency.In this study,we conducted a systematic review of spatial targeting methods based on literature analysis using Citespace.Firstly,peer-reviewed articles related to spatial targeting of PES were selected from the Web of Science database based on keywords.Cases applying PES spatial targeting methods were then chosen and analyzed after all articles were read.In total,70%of the chosen cases focused on improving the compensation efficiency of biodiversity or another single environmental objective,whereas the remaining cases focused on coordinating trade-offs between equity and efficiency or multiple environmental objectives.The main PES spatial targeting approaches included cost-benefit analysis,multi-objective optimization,data envelope analysis and other methods aimed at specific issues.Of these,cost-benefit analysis has been most widely applied at different scales,including county,regional and watershed scales.Significant differences among the different PES spatial targeting methods were found,including in PES spatial targeting dimensions,efficiency optimization approaches and method application conditions.The practice of PES spatial targeting requires the selection of appropriate methods based on contextual biophysical and socioeconomic conditions as well as relevant environmental issues.The combined application of PES spatial targeting methods,compensation willingness of stakeholders and dynamic implementation of PES spatial targeting should be considered in future research.

Processing Methods for Conical Scan Hopped-Frequency Signal

The new radar system of combination of the hopped-frequency with the conical scan is presented. According to the principle and expression of the conical scan hopped-frequency signal, the angle processing method in which angle information is obtained by taking discrete Fourier transform （DFT） for the conical envelop of each scattering centre by means of high range resolution profile （HRRP） is presented, and the corresponding formula is derived. The influence of non-ideal factors, such as amplitude fluctuation noise and system noise, leakage of time and frequency domain, unstable rotation of antenna, and missile rotation, on angle-measurement precision and the possible solving methods are also focused on. The simulation results show that the combination of the hopped-frequency and conical scan system could get satisfactory angle information, which could ensure good quality when used in practical tracking radar.