Antenna Control Unit Research Articles

An enhanced cross‐layer solution for IFC applications using HTS systems at Q/V‐band

The Q/V band communication systems open new avenues for next generation of high-throughput satellite (HTS) systems. More specifically, they are attractive due to their high bandwidth for user and gateway links. Having a wide bandwidth at Q/V band makes it permissible to offload the links between the satellite and its earth station hubs (gateway) from the Ka band to the Q/V band. This enables additional bandwidth available for HTS feeder links and user links of specific market verticals, which in turn results in reduction of cost per bit for in-flight connectivity applications to provide WiFi capability on the aircraft. This study provides a deep overview of network architecture at the ground gateway infrastructure with respect to the network management system (NMS) to optimize network traffic utilization. We have looked at a gateway constellation platform which optimizes the actual cost-efficient solution for deploying routing user traffic among the networks. In addition, the study discusses the elements involved in the NMS which interfaces with the gateway platform. The overall NMS platform design and capabilities are discussed as they provision the network service parameters throughout the entire operation. The proposed solution integrates the physical antenna, antenna control unit and the power supply into one bundle on the aircraft. This will result in approximately 10% throughput increase compared to conventional methods that do not deploy N+P gateway architecture. The proposed method has enhanced spectrum efficiency along with the NMS unit that has been discussed in detail. Finally, a wideband and multibeam antenna is introduced as an essential part of the solution followed up by simulation results.

Analysis of the communication links between the AlSat‐1b satellite and the ground station: The impact of the Auto Tracking system on antenna pointing accuracy

SummaryThe communication links between a satellite and the Earth station (ES) are exposed to many impairments such as noise, rain, and atmospheric attenuations. They are also prone to loss such as those resulting from antenna pointing and polarization. The Algerian Earth Observation satellite AlSat‐1b is designed to accomplish its mission in S‐band (Telecommands and Telemetry) and X‐band (images) frequencies in low Earth orbit (LEO). The ground segment (GS) of this satellite, situated in Oran, Algeria, is based on the X/Y antenna mounting system with 7.3‐m dish diameter. This large reflector can cause antenna pointing errors. The Antenna Control Unit (ACU) implemented in this station can be configured with or without an AutoTrack system. In this work, operational tests and analysis of the different communication links between AlSat‐1b and the ground station are presented. The obtained results clearly show that the quality of the S‐band links can reliably and efficiently satisfy the requirements without the use of the AutoTrack. On the contrary, the use of AutoTrack is necessary in order to obtain an improved level of link quality in the X band.

Time and Frequency Synchronization on the Virac Radio Telescope RT-32

Abstract One of the main research directions of Ventspils International Radio Astronomy Centre (VIRAC) is radio astronomy and astrophysics. The instrumental base for the centre comprised two fully steerable parabolic antennas, RT-16 and RT-32 (i.e. with the mirror diameter of 16 m and 32 m). After long reconstruction, radio telescope RT-32 is currently equipped with the receiving and data acquisition systems that allow observing in a wide frequency range from 327 MHz to 9 GHz. New Antenna Control Unit (ACU) allows stable, fast and precise pointing of antenna. Time and frequency distribution service provide 5, 10 and 100 MHz reference frequency, 1PPS signals and precise time stamps by NTP protocol and in the IRIG-B format by coaxial cable. For the radio astronomical observations, main requirement of spatially Very Long Base Line Interferometric (VLBI) observations for the observatory is precise synchronization of the received and sampled data and linking to the exact time stamps. During October 2015, radio telescope RT-32 performance was tested in several successful VLBI experiments. The obtained results confirm the efficiency of the chosen methods of synchronization and the ability to reproduce them on similar antennas.

The Design of RFID Conveyor Belt Gate Systems Using an Antenna Control Unit

This paper proposes an efficient management system utilizing a Radio Frequency Identification (RFID) antenna control unit which is moving along with the path of boxes of materials on the conveyor belt by manipulating a motor. The proposed antenna control unit, which is driven by a motor and is located on top of the gate, has an array structure of two antennas with parallel connection. The array structure helps improve the directivity of antenna beam pattern and the readable RFID distance due to its configuration. In the experiments, as the control unit follows moving materials, the reading time has been improved by almost three-fold compared to an RFID system employing conventional fixed antennas. The proposed system also has a recognition rate of over 99% without additional antennas for detecting the sides of a box of materials. The recognition rate meets the conditions recommended by the Electronic Product Code glbal network (EPC)global for commercializing the system, with three antennas at a 20 dBm power of reader and a conveyor belt speed of 3.17 m/s. This will enable a host of new RFID conveyor belt gate systems with increased performance.

Application of the Field System-FS9 and a PC to the antenna control unit interface in radio astronomy in Peru

AbstractWe are in the process to transform a 32m antenna in Peru, used for telecommunications, into a Radio Telescope to perform Radio Astronomy in Peru. The 32m antenna of Peru constructed by NEC was used for telecommunications with communications satellites at 6 GHz for transmission, and 4 GHz for reception.In collaboration of National Institute of Information and Communications Technology (NICT) Japan, and National Observatory of Japan we developed an Antenna Control System for the 32m antenna in Peru. It is based on the Field System FS9, software released by NASA for VLBI station, and an interface to link PC within FS9 software (PC-FS9) and Antenna Control Unit (ACU) of the 32 meters antenna.The PC-FS9 controls the antenna, commands are translated by interface into control signals compatibles with the ACU using: an I/O digital card with two 20bits ports to read azimuth and elevation angles, one 16bits port for reading status of ACU, one 24bits port to send pulses to start or stop operations of antenna, two channels are analogue outputs to drive the azimuth and elevation motors of the antenna, a LCD display to show the status of interface and error messages, and one serial port for communications with PC-FS9.The first experiment of the control system was made with 11m parabolic antenna of Kashima Space Research Center-NICT, where we tested the right working of the routines implemented for de FS9 software, and simulations was made with looped data between output and input of the interface, both test were done successfully.With this scientific instrument we will be able to contribute with researching of astrophysics. We expect to into a near future to work at 6.7GHz to study Methanol masers, and higher frequencies with some improvements of the surface of the dish.

Electronically Tunable Antenna Pair and Novel RF Front-End Architecture for Software-Defined Radios

This paper proposes a novel RF front-end architecture for software-defined radios (SDRs) based on an electronically tunable antenna pair controlled by an antenna control unit (ACU) consisting of field effect transistor (FET) switches and a field programmable gate array (FPGA). The fundamental gain-bandwidth limitations of electrically small antennas prevent a small antenna from having high efficiency and wide bandwidth simultaneously. In the age of miniaturization, especially in the wireless communication industries, a promising solution to this limitation is to introduce reconfigurable antennas that can be tuned electronically to different frequency bands with both high efficiency and narrow instantaneous bandwidth. This reconfigurable antenna technology not only simplifies current RF front-end architectures, but can be reprogrammed on demand to transmit and receive RF signals in any desired frequency band. This novel RF front-end architecture implemented by a reconfigurable antenna pair can help realize SDRs.

NORAD TLE TYPE ORBIT DETERMINATION OF LEO SATELLITES USING GPS NAVIGATION SOLUTIONS

NORAD Two Line Elements (TLE) are widely used for the increasing number of small satellite mission operations and analysis. However, due to the irregular periodicity of generation of the NORAD TLE, a new TLE that is independent of NORAD is required. A TLE type Orbit Determination (TLEOD) has been developed for the generation of a new TLE. Thus, the TLEOD system can provide an Antenna Control Unit (ACU) with the orbit determination result in the type of a TLE, which provides a simple interface for the commercialized ACU system. For the TLEOD system, NORAD SGP4 was used to make a new orbit determination system. In addition, a least squares method was implemented for the TLEOD system with the GPS navigation solutions of the KOMPSAT-1. Considering both the Orbit Propagation (OP) difference and the tendency of value, the preferable span of the day in the observation data was selected to be 3 days. Through the OD with 3 days observation data, the OP difference was derived and compared with that of Mission Analysis and Planning (MAPS) for the KOMPSAT-1. It has the extent from 2 km after sit days to 4 km after seven days. This is qualified enough for the efficiency of an ACU in image reception and processing center of the KOMPSAT-2.

Computer based Earth Station Tracking Chain Simulator to aid the Development and Evaluation of Antenna Control Systems

In this paper a computer based tracking chain simulator for aiding the development and testing of antenna control systems of satellite earth stations is presented. User-friendly software with graphic-display facilitates system simplicity. Simulation reduces the integration and optimization time of the tracking chain, since most of the parameters can be set in the laboratory itself. The hardware block schematic and the software flow chart are discussed. The simulator has been successfully used to test and optimize an antenna control unit developed for the International Satellite Monitoring Earth Station (ISMES), Jalna, India.