Antenna Tracking Techniques for Long Range Air-to-Ground Communication Systems Using a Monopulse Method

Jaesin Kim,Jaemoon Lee,Inkyu Lee

doi:10.1109/access.2020.3022932

Jaesin Kim, Jaemoon Lee + Show 1 more

Open Access

https://doi.org/10.1109/access.2020.3022932

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Abstract

In this paper, we consider long range air-to-ground (AG) communication systems which support airborne platforms including unmanned aerial vehicles (UAVs) for real-time applications. In this system, we design tracking techniques for directional ground antennas which enable reliable AG communication regardless of dynamic maneuvers of the UAV. We apply a simple monopulse method and a fixed gain filtering algorithm to develop a single channel monopulse tracking system with an angular estimation filtering, which exploits a downlink signal without requiring a dedicated channel. Through the AG communication prototype and realistic flight tests, we evaluate the tracking accuracy performance at the distance of hundreds of kilometers and demonstrate the auto-tracking capability of the angular estimation filter. The flight test results show that the tracking accuracy of our proposed system is sufficient for long range transmission with a narrow beam antenna. Also, in the absence of the downlink signal, it is observed that the ground prototype can resume the monopulse tracking procedure, and successfully maintains the tracking accuracy.

Highlights

In recent years, there have been increasing interests in utilizing airborne platforms for various real-time applications such as military reconnaissance, disaster monitoring, border patrol, and airborne communication networks [1], [2]
We develop a single channel monopulse tracking system with additional estimation filtering for the wideband and long range AG communication systems
Motivated by the channel reducing methods reported in [20] and [22], we focus on a simplified single channel approach that requires only one intermediate frequency (IF) chain for the monopulse method

Summary

INTRODUCTION

There have been increasing interests in utilizing airborne platforms for various real-time applications such as military reconnaissance, disaster monitoring, border patrol, and airborne communication networks [1], [2]. Some works studied the AG communication system in the context of directional tracking antennas [15]–[19] They are still limited in UAV systems with short coverage and low altitude. J. Kim et al.: Antenna Tracking Techniques for Long Range AG Communication Systems Using a Monopulse Method. We develop a single channel monopulse tracking system with additional estimation filtering for the wideband and long range AG communication systems. By subtracting the out-of-phase signal and adjusting two parameters, we demonstrate that the proposed single channel monopulse technique with reduced complexity obtains the performance almost identical to the conventional three channel system. The work [22] analyzed angle estimation methods for orthogonal frequency division multiplexing based single channel monopulse tracking in the UAV AG communications.

SIMPLIFIED SINGLE CHANNEL MONOPULSE TRACKING SYSTEM

FLIGHT TEST RESULTS

EXPERIMENTAL SETUP

CONCLUSION