Imaging and Localisation Package for a Martian Balloon Based

Aerobot

Dave Barnes, Andy Shaw, Phil Summers

Roger Ward, Mark Woods, Malcolm Evans

Gerhard Paar, Mark Sims

ESA Contract No. 17400/03/NL/CH

Contents

• ILP overview

• Balloon gondola hardware

• Balloon localisation

• Balloon simulator

• The way forward

Balloon Imaging Mission

Imaging and Localisation Package

• The package will allow optimal acquisition of images to reconstruct accurate models of the surface of the explored planet, and accurate localisation of the balloon with respect to the Martian surface. The ILP by means of aerobot mounted cameras and computer vision techniques will: a) acquire and store images of the surface at various resolutions, b) construct and update a 3D model (DEM) of the surface, (cont..)

Imaging and Localisation Package

• c) constantly estimate the position (latitude, longitude and altitude) of the aerobot as well as its motion with respect to the surface, and d) decide on the base of the communications budget, of the morphology of the surface and of the information content of the images, which images at which resolution/compression need to be transmitted to Earth.

Image Acquisition Problem

Satellite Transmission Problem

SOW ILP Overview

Contents

• ILP overview

• Balloon gondola hardware

• Balloon localisation

• Balloon simulator

• The way forward

Hardware Overview

• Balloon envelope

• Propulsion system

• Altimeter

• Camera

• On-board processor

• Mock terrain

Balloon Lift

• A 1830 mm ( 6 ft) diameter balloon will produce a total lift of 3 kg

• PVDC envelope mass =1 kg– Gondola mass = 2 kg

•  Mylar envelope mass = 0.3 kg– Gondola mass = 2.7 kg

AVI - Early Propulsion System

HardwareOverview

Firewire interface (IEEE1394), supplies power (12V), allows 400Mbps, raw data. 30fps @ 640x480

RS232 serial interface, 2Hz, accuracy of 1.5mm

Allows communication to a base PC at 11Mbps and allows simulation of the comms window.

Supplies power to the whole system 14.8V 5850mAh

Small PC running a P4M 2.4Ghz, 512Mb RAM, 20Gb HDD, requires +5V @ 4.2A, +12V @ 4.85A Total 35W

Complete Gondola Structure

ILP Gondola Camera Calibration

Gondola Captured ESTEC PTB Image Mosaic

Contents

• ILP overview

• Balloon gondola hardware

• Balloon localisation

• Balloon simulator

• The way forward

Localisation Approach

To maintain localisation accuracyover large aerobot flight distances,our ILP approach augments a relativelocalisation method with an additionalglobal localisation approach.

Relative Localisation

Global Localisation

FEATURE AND GRADIENTMATCHING METHODS USED

Local Aerobot ILPGenerated DEM

Global Orbiter DEM Showing Localised Balloon

E.G. MGSMOLA DATAWITHEXTRACTEDFEATURES

Contents

• ILP overview

• Balloon gondola hardware

• Balloon localisation

• Balloon simulator

• The way forward

Balloon Simulator Overview

ILP MartianBalloon

Simulator

Terrain Data:MOLA, MOC,

THEMIS

MartianMeteorology:ESA MCDB

& CFD

BalloonAerodynamics

Model

GondolaInstrumentation

Modele.g. Camera

Balloon Simulator Screen Shot

Beagle 2 landing ellipse and crater ‘H’

Image courtesy THEMIS ASU Team and MSSS

Shape from shading – crater ‘H’

Balloon Simulator Overview

ILP MartianBalloon

Simulator

Terrain Data:MOLA, MOC,

THEMIS

MartianMeteorology:ESA MCDB

& CFD

BalloonAerodynamics

Model

GondolaInstrumentation

Modele.g. Camera

3D Navier-Stokes Martian Wind

Contents

• ILP overview

• Balloon gondola hardware

• Balloon localisation

• Balloon simulator

• The way forward

Tethered Martian Balloon Study

• Martian Atmospheric Parameters?– Location, Temperature, Pressure, Wind Speeds

• Balloon Envelope Parameters?– Material, Density, Thickness, Permeability

• Balloon Tether Parameters?– Material, Density, Young’s Modulus, Balloon Altitude (500m)

• Rover (or Lander) Related Parameters?– Winch Mass (incl. electronics), Gas Storage

• Science Instrument Mass?– Instruments, Power, Communications, Electronics (1kg)

InnovativeBalloon Lift Methods

TetheredHybridBalloon/KiteExperiments