Joshua Tristancho

Next generation of sensors for femto-satellites based on commercial-of-the-shelf

Femto-satellites are satellites with a mass lower than 100 grams. These new categories of satellites are, by concept, low cost devices if they are based on Commercial-of-the-Shelf (COTS) components. Some examples of applications are related to low-cost missions with short time of development. In addition, if they use Low Earth Orbits like 250 kilometers, they use the orbit for few weeks and then the orbit is free to be reused. This new point of view will allow us to design and to use new kind of strategies more dedicated to a particular mission and at the same time adaptive to unpredictable needs like to provide dynamic support for earthquakes. In this paper we present a study of the current sensors like QUICKBIRD, WORLDVIEW and 20 more, very often used in these kind of emergencies, in the direction to, in one hand, to identify which kind of sensors are required for such missions. In the other hand we study the COTS market of sensors that can be installed on-board of a femto-satellite in terms of higher performances, low cost and low consumption. Each sensor selected was validated for space conditions assuming small areas of scanning, short periods of exposure to the outer space environment, high acceleration and high vibrations.

A synthetic aperture antenna for femto-satellites based on commercial-of-the-shelf

Femto-satellites are very small satellites weighing less than 100 grams and by concept they are low cost. These kinds of satellites are very often based on the so called Commercial-Of-The-Shelf components. They are suitable for applications with low budget and with short time of development. The satellite remains in a Low Earth Orbit (LEO) of 250 kilometers for few weeks, and afterwards the orbit can be reused. A new strategy is considered that consists in dedicating the whole satellite to a particular mission, the satellite can be reprogrammed in orbit to provide dynamic support for Disaster Management in natural disasters such as earthquakes. A big issue for such tiny satellites is the communications. They should achieve a link budget of hundreds of kilometers with hundreds of thousands bits per second with a power budget of few watts. The directivity of the antenna and the accuracy to point ground stations should be increased. Also the antenna works as the satellite structure. In this paper a synthetic aperture antenna for femto-satellites based on Commercial-Of-The-Shelf is presented. This implementation meets all the previous requirements as a proof of concept. Different configurations of ceramic antennas array were used. Some transceivers and High Gain Amplifiers were tested. A semi-anechoic chamber results are also presented describing the antenna radiation pattern. In order to change the phase of each ceramic antenna, passive components were used like micro-strips.

Optical wireless interface for the ARINC 429 avionics bus: Design and implementation

A complete optical wireless interface for the ARINC 429 avionics bus has been presented as part of this paper. After evaluating the previous results, we conclude that the described system complies with all electrical and timing restrictions imposed by the ARINC 429 specification, ensuring the compatibility with such avionics bus.

Experimental approach to an optical wireless interface for an avionics data bus

There are physical spaces and infrastructure environments in which conventional radio-frequency (RF) wireless systems can result in hazardous conditions due to the intrinsic risk of producing high levels of electromagnetic interference (EMI), which can affect sensitive electronic equipment placed in proximity of such high energy RF sources. Two good examples of infrastructures where the levels of EMI are severely restricted are hospitals and aircrafts. In the former stated examples, the failure of any critical system due to electromagnetic interference can lead to severe injury or loss of human life. Aviation industry can result largely benefited by the incorporation of wireless avionics capabilities, mainly due to the dramatic weight reduction associated to the removal of electrical wires. This significant weight reduction will inherently help to reduce operational costs. Nevertheless, classical RF technology cannot be used in this scenario because of the reasons previously exposed. This paper describes the implementation of a wireless optical interface for an avionics data network, which provides wireless capability without generating any electromagnetic interference to other systems already present in the aircraft. The presented interface acts completely transparent to an existent avionics bus topology and implies no modification whatsoever to any equipment already compatible with the bus.

An Electromagnetic Interference Reduction Check List for Unmanned Aircraft System

Unmanned Aircraft Systems may allow to y an uninhabited airplane or satellite with an autonomous control and monitored by the supervisor on ground. Safety y must be guarantee as the rest of airworthiness airplanes or space compliance satellites. The Unmanned Aircraft Systems were designed to operate in dangerous situations, like military missions bud nowadays, civil commercial applications come to be feasible due to the evolution in distributed embedded avionics systems. Dull and tedious surveillance applications are desired for this Unmanned Aerial Vehicles. A pico-satellite is a less than a kilogram mass satellite used mainly on educational projects for Low Earth Orbit (LEO) missions. Due to short time of live, down-link communications are implemented in a very high level of integration and non-gravity conditions in order to deliberate the scienti c information before drop down to the atmosphere. Both, Unmanned Aerial Vehicles and pico-satellites present same electromagnetic compatibility problems. This high level of integration, some times brings an electromagnetic interference situation between embedded systems especially because the near eld of emissions are present in the Unmanned Aircraft System reduced con ned avionics bay. Emission, Susceptibility, and Path are playing in this environment. That was our experience with an UAV Megastar model. The near earth antenna re ection produced a multi-path coupling. The radio transmitter antenna makes unserviceable the entire ight control surfaces, situation that makes an unsafe y. Also, during the pico-satellite design we must take in consideration the near eld for a good electromagnetic compatibility requirements. This paper is an electromagnetic compatibility study for Unmanned Aircraft System. We will show a case of real electromagnetic interference in our particular UAV Megastar, and how was solved. We will present some good EMC practices in order to translate the distributed embedded avionics platform to our new UAV Shadow MK1. Also we present our pico-satellite design and many examples of solutions of electromagnetic interferences. Finally we will consider an electromagnetic interference reduction check list applied on Unmanned Aircraft System where avionics bay con guration may change depending on the requirements of the mission.

A telemetry modeling for intelligent UAV monitoring

An Unmanned Aerial Vehicle, UAV for short, is able to fly autonomously during all phases of flight, but has to be monitored from an operator station. In this article a better avionic system is proposed to optimize this process reducing the channel usage without quality degradation. The information related to the aircraft position is called telemetry. This early avionic system is tested in the longitudinal mode of a high wing model unmanned aircraft system in an open source flight simulator.

Synthetic vision for Remotely Piloted Aircraft in non-segregated airspace

Synthetic Vision Systems (SVS) provide a computer-generated depiction of the environment according to aircraft flight path and attitude. In the case of Remotely-Piloted Aircraft (RPA), SVS improve dramatically operator situation awareness under reduced visibility conditions due to environment related issues and/or video data link degradation. Even though at their definition NextGen/SESAR frameworks were not thought to integrate RPA operations into non-segregated airspace, concepts such as flow corridors and technologies such as Traffic Information Service — Broadcast will ease their incorporation. This paper proposes and assesses new concepts applied to SVS in order to increase RPA operator situation awareness taking advantage of new data sources that may be available in the future NextGen/SESAR frameworks. Based on raw telemetry data and accessible terrain databases, a SVS is built. The integration of trajectory data and air traffic information is designed and implemented in order to determine its benefits.

Service Oriented Fast Prototyping Environment for UAS Missions

This paper introduces a simulation architecture to evaluate the implementation of a va- riety of civil UAS missions with little recon guration time and overhead. This architecture, called Icarus Simulation Integrated Scenario (ISIS), is capable of simulating the behavior of the UAS from the mission point of view, but also is able to include additional aerial/ground vehicles. Additionally, the mutual interaction between vehicles and the interaction with their surrounding environment is modeled. The objective of ISIS is to minimize both the development e ort and risk, as well as to provide a feasible migration of the software from the testbed platform to the real ight platform. The UAS simulator is designed as a distributed simulation architecture in which vehicles and environment are modeled through specialized pieces of software. A service-oriented communication middleware provides the underlying infrastructure to easily implement the inter-vehicle coordination and even the coordination with third party applications providing additional simulated vehicles or simulated environment. A UAS-based forest re monitor- ing application is selected to describe the ISIS capabilities to coordinate the simulation of a multi-vehicle cooperative environment developing a complex mission.

A probe of concepts for femto-satellites based on COTS

• It is possible to build a low cost, low weight and good enough performance Femto-Satellite • This Femto-Satellite built by the Wikisat team is based on Commercial-Of-The-Shelf and fulfills the N-Prize requirements • A list of subsystems and the preferred components were described

NextGen of sensors for femto-satellites based on COTS

• Femto-Satellites will be useful only if they have good sensors • A summary of latest satellites for Earth observation in Disaster Management was presented • A number of requirements for the next generation of sensors were discussed like: — Really small size — Low power — SMD surface mounted — Lens included if possible • A list of next generation sensors was presented able to be installed in a real femto-satellite