Impact Of Elements On GNSS Anti-jamming Array Performance And Research On High-precision Antenna Radome Technology

After decades of rapid development,the Global Navigation Satellite System(GNSS)has become an important space infrastructure for providing position,velocity and timing(PVT)information.The GNSS antenna or antenna array is the first device of the receiver,and its performance indicators play a crucial role in the performance of the entire receiver.And the high-precision GNSS antennas employed in the monitoring stations widely require the protection of radome,which has a non-negligible influence on the performance of high-precision antenna.The adaptive antenna array controls the pattern by the adaptive weights,steering nulls in the direction of interference or forming a beam in the direction of the satellite signal.The element pattern characteristics have a complicated impact on the anti-jamming performance of the array.Based on the application of GNSS anti-jamming antenna array and high precision antenna,this paper deeply studies two key topics: the impact of element pattern characteristics on the antenna array performance and the influence of radome on the high-precision antenna performance.The main research contents and innovative results include:(1)The traditional methods of analyzing antenna array performance generally assume that the elements are ideal omnidirectional antenna,and ignore the influence of element pattern characteristics.In order to solve this problem,based on the pattern characteristics of microstrip patch antenna,the influence of ideal element characteristics on array gain and availability are demonstrated in this paper.The simulation experiments illustrate that the PI algorithm essentially forces the elements to be in an unequal position leading to the domination of the radiation characteristic of the reference element to the adaptive array gain,while the influence of non-reference element pattern characteristics on the array gain can be ignored.Moreover,the shortage of the availability is analyzed based on the experimental results,pointing out that it is necessary to compare the availability in the case of the same number of interferences and array elements.(2)The non-ideal factors in the actual antenna array seriously affect the pattern characteristics of the elements,and then affect the array gain and availability.In order to solve this problem,this paper analyzes the influence of two common non-ideal factors including the mutual coupling and the floor-edge effect.It is found that the non-ideal pattern has the characteristics of gain attenuation,directivity deflection and back radiation energy enhancement.A simulation platform of the antenna array anti-jamming is established,and the effects of two non-ideal factors on the availability are verified.It is concluded that the edge effect of the floor will cause the decrease of array availability.However,the conventional conclusion that the mutual coupling deteriorates the performance of the antenna array is not accurate.The effects of mutual coupling on array availability need to be judged in combination with the specific incident scenarios and array geometries.The practical antenna array analysis method based on the characteristics of non-ideal array elements is given,and the feasibility of array miniaturization is analyzed.(3)In the fixed ground station application,the introduction of radome directly will affect the performance of internal high-precision antenna.To solve this problem,the mathematical model of electromagnetic wave reflection and refraction through the radome is established,and the gain loss and axial ratio of the transmitted wave are analyzed.The radome parameters affecting the performance of high-preicsion antenna are derived.The general analysis methods for designing the radome indicators are given.The radomes of different materials,geometries and height parameters are compared and analyzed to obtain a hemispherical-cylindrical radome with fiber reinforced plastic material and a height of 345 mm which will minimize the performance degradation of high-precision antennas.The prototype of antenna-radome system was designed and manufactured.According to the measured data,the axial ratio of antenna is kept within6 d B within any elevation angle,which is less than 2 d B in all working frequency bands with the elevation angle in the range of 0°-60°.The antenna-radome system is guaranteed to have a good circular polarization performance in the L-band or S-band.