Electrification turned over a new leaf in aviation by introducing new types of aerial vehicles along with new means of transportation. Addressing a plethora of use cases, drones are gaining attention in the industry and increasingly appear in the sky. Emerging concepts of flying taxi enable passengers to be transported over several tens of kilometers. Therefore, unmanned traffic management systems are under development to cope with the complexity of future airspace, thereby resulting in unprecedented communication needs. Moreover, the long-term increase in the number of commercial airplanes pushes the limits of voice-oriented communications, and future options such as single-pilot operations demand robust connectivity. In this survey, we provide a comprehensive review and vision for enabling the connectivity applications of aerial vehicles utilizing current and future communication technologies. We begin by categorizing the connectivity use cases per aerial vehicle and analyzing their connectivity requirements. By reviewing more than 500 related studies, we aim for a comprehensive approach to cover wireless communication technologies, and provide an overview of recent findings from the literature toward the possibilities and challenges of employing the wireless communication standards. After analyzing the proposed network architectures, we list the open-source testbed platforms to facilitate future investigations by researchers. This study helped us observe that while numerous works focused on cellular technologies to enable connectivity for aerial platforms, a single wireless technology is not sufficient to meet the stringent connectivity demands of the aerial use cases, especially for the piloting operations. We identified the need of further investigations on multi-technology heterogeneous network architectures to enable robust and real-time connectivity in the sky. Future works should consider suitable technology combinations to develop unified aerial networks that can meet the diverse quality of service demands of the aerial use cases.

A Survey of Wireless Networks for Future Aerial Communications (FACOM)

CubeSats have been widely used for space research due to lower cost and faster development The electric power system (EPS) is one of the key subsystems of CubeSat which powers all the other subsystems One of the important steps in the EPS design is the selection of EPS architecture which should be done considering overall efficiency, battery size, reliability, and simplicity of control In the literature, a general comparison between different architectures is performed without considering the mission parameters, power generation profile, and load profile based on the operational modes Thus, the best possible EPS architecture may not be selected in the design phase Therefore, the main objective of this article is to develop a systematic methodology to compare various peak power tracking EPS architectures of CubeSat in terms of orbital efficiency for all possible modes of operation, component count, reliability, and battery size to meet the required number of cycles of charge/discharge for the given mission duration The proposed methodology has been demonstrated using the real data and scenarios of MYSAT-1, which is a 1U CubeSat developed and launched by Khalifa University The results demonstrate that EPS architecture with series-connected maximum power tracking converters for solar panels and unregulated dc-bus has the highest efficiency for all operating modes, lower component count, higher reliability, and minimum battery capacity or longer lifetime for the same battery specifications

Comparison of Peak Power Tracking Based Electric Power System Architectures for CubeSats

We are in the midst of a revolution in satellite technology, with the rapid development and advancement of small satellites (or SmallSats, i.e., satellites <180 kg). Here, we review the opportunities and challenges that such technology might afford in the field of conservation and ecology. SmallSat constellations may yield higher resolutions than those that are currently available to scientists and practitioners, increasing opportunities to improve environmental-monitoring and animal-tracking capabilities. They may cut access costs to end users, by reducing operational costs and bringing increased competition to the existing market. Their greater flexibility and affordability may moreover enable the development of bespoke constellations for specific conservation and ecological applications, and provide greater interoperability with ground-based sensors, such as tracking devices and camera traps. In addition, SmallSats may serve as cost-effective research and development platforms for new components and products. Combined, these benefits could significantly improve our ability to monitor threats to the environment as they unfold, while enhancing our understanding of animal ecology and ecosystem dynamics. However, significant hardware and software developments are required before such technology is able to produce, process and handle reliable and cost-effective data, and the initial research and development costs still represent a major challenge. Further, we argue that much remains to be done to ensure these new data products become accessible, equitable and sustainable.

SmallSats: a new technological frontier in ecology and conservation?

CubeSats have been popular for space research due to lower cost, faster development, and easier deployment. The electrical power system (EPS) is one of the significant subsystems for the CubeSat since it handles power generation, energy storage, and power distribution to all other subsystems. Therefore, the design of EPS becomes crucial for successful CubeSat mission, wherein the first step is the selection of EPS architecture. The main objective of this article is to present an extensive review of all the conventional and emerging EPS architectures of CubeSats. A total of 17 categories of CubeSat EPS architectures have been identified, classified, and the operational aspects of these architectures are presented in addition to a qualitative comparison. This article is expected to provide a useful reference guide for all the researchers and developers working in the area of CubeSats EPS. Also, some of the potential research topics are provided to further exploration and innovation for the CubeSat EPS. 

A Comprehensive Review on CubeSat Electrical Power System Architectures

This paper discusses the development and characterization of wideband substrate-integrated-waveguide (SIW) bandpass filter (BPF) incorporated with two reversely arranged complimentary-split-ring-resonators (CSRRs). The proposed filter is intended to have bandwidth response more than 8 GHz suitable for applications in wireless communication systems. The incorporation of CSRRs on the SIW surface allows the extension of passband area at the higher frequency region yielding the wideband response of filter. A 1.6 mm thick FR4 epoxy dielectric substrate with the dimension of $40\ \text{mm}\times 45\ \text{mm}$ is applied for filter implementation. The characterization result shows that the proposed filter has the fractional bandwidth of around 135% at the center frequency of 6.74 GHz. This result was achieved through measurement setup to demonstrate a good agreement between the simulation and experimentation.

Wideband Substrate-Integrated-Waveguide BPF Incorporated with Camplimentary-Split-Ring-Resonators

This paper presents the U-shaped defected ground structure (DGS) which is incorporated into the groundplane of array antenna to reduce the coupling between antenna elements. The array antenna is constructed of two layers of flame resistant (FR) 4 epoxy dielectric substrate with the thickness of each layer of 1.6mm. The U-shaped DGS is placed at the bottom side of second layer between two elements of array antenna located on the top side of first layer. A proximity feeding technique of microstrip line applied to feed each antenna element is positioned on the top side of second layer. By reducing the coupling which is generated due to the input power at both feeding ports, the radiation characteristics of array antenna can be improved. To demonstrate the feasibility of U-shaped DGS in coupling reduction, an array antenna without DGS is also investigated. The characterization results have verified that the U-shaped DGS is applicable to reduced the coupling at the resonant frequency of 2.38GHz up to 2dB and 0.88dB for simulation and measurement, respectively.

Coupling reduction between two elements of array antenna using U-shaped defected ground structure

Automatic Dependent Surveillance-Broadcast (ADS-B) is a surveillance technology applied to aircrafts for air traffic control with GPS and satellite based. ADS-B worked by receive messages from the aircraft which sends information periodically. At this moment, not all areas are covered by ADS-B. To obtain ADS-B data from the aircraft required a device consisting of a computer, a radio receiver and an antenna to obtain some real time flight information. This project is about designing a prototype for the nanosatellite that acts as a receiver of ADS- B messages that transmitted by the aircraft with a working frequency of 1090MHz and using RTL-SDR RTL2832U as the receiver and Raspberry Pi 3 Model B as On Board Data Handling (OBDH). In this paper, the prototype of ADS- B payload has been successfully designed and implemented. ADS-B payload have a success rate of 91.3% and an accuracy rate of 98.45% in the area of Telkom University. For measurements in the Ciburial area, Bandung, it have a success rate of 90.62% and an accuracy rate of 99.25%. The farthest distance obtained by the payload is 85.30 Km. The payload successfully storing data with. txt file extension format on 0.868 seconds/message.

Nanosatellite ADS-B Receiver Prototype for Commercial Aircraft Detection

Synthetic Aperture Radar (SAR) is one of radar techniques which is usually applied to improve the resolution of azimuth detection using smaller antenna size. One of its applications is for space-based remote sensing using satellite since it can get larger observation area than other SAR platforms. However, the payload of space-based SAR using satellite should satisfy some requirements in mass, power, and dimension. This paper discusses the development of SAR transmitter for nanosatellite-based remote sensing application. It is developed based on frequency modulated continuous wave (FMCW) waveform as a chirp generator which is implemented using a direct digital synthesizer (DDS) technique. Here, the use of DDS technique is to simplify the development of SAR transmitter circuit. The DDS component used in the development is an integrated circuit of AD9850 from Analog Device controlled by an ARM-based μcontroller. The chirp bandwidth FMCW waveform is 10MHz with 1 μs duration which has the range resolution of 15m.

Development of SAR transmitter for nanosatellite-based remote sensing application

A computational approach for resonant frequency calculation of coaxial cavity resonator using a cylindrical coordinate system-based finite difference time domain (FDTD) method is presented. Due to the geometry shape of analyzed structure, i.e. coaxial cavity resonator, the use of FDTD method with cylindrical coordinate system is chosen instead of Cartesian coordinate system. A coaxial cavity resonator made of perfect conductor with outer diameter of 100mm, inner diameter of 40mm and length of 150mm is modeled and discretized based on FDTD notation and then numerically computed to determine its resonant frequencies in the frequency range of 1–5GHz. Moreover, a simulation using finite element method (FEM) commercialized software is also conducted to determine resonant frequencies of the resonator for comparison. From the results, it shows that the proposed FDTD approach demonstrates the capability to determine resonant frequencies of coaxial cavity resonator with an acceptable accuracy compared to the FEM commercialized software in the maximum discrepancy around than 3%.

Computational approach for resonant frequency calculation of coaxial cavity resonator using cylindrical coordinate system-based FDTD method

In this paper, a design of 1:8 power divider is proposed for S-band array antenna feeding network. The proposed power divider which is designed based on Cohn topology is implemented on an RO4003C dielectric substrate which has the relative permittivity and the thickness of 3.55 and 1.524mm, respectively. Seven pairs of 1:2 power divider are used to construct the design of 1:8 power divider. Some parameters such as insertion, isolation and voltage standing wave ratio (VSWR) are used to analyze the performance of power divider in the frequency range of 2–4GHz. The result shows that the 1: 2 power divider has the values of insertion loss, isolation and VSWR of greater than 3.08dB, greater than 24dB, and less than 1.1, respectively. Meanwhile, the 1:8 power divider has the insertion value of greater than 9.26dB, isolation value of greater than 23dB, and VSWR value of less than 1.5. The characterization result has shown an adequate performance for S-band array antenna feeding network of radar system.

Edwar

Papers

Coupling reduction between two elements of array antenna using U-shaped defected ground structure

Nanosatellite ADS-B Receiver Prototype for Commercial Aircraft Detection

Development of SAR transmitter for nanosatellite-based remote sensing application

Computational approach for resonant frequency calculation of coaxial cavity resonator using cylindrical coordinate system-based FDTD method

Cohn topology-based 1:8 power divider for S-band array antenna feeding network