The challenge

Satellites need to be regularly calibrated

Earth observation satellites need to be regularly calibrated to ensure the accuracy of their observations. This is done using a process called vicarious calibration, which involves ground crews walking in grids or transects and taking measurements with hand held devices called spectrometers.

This happens at the same time the satellite is travelling overhead, and the two sets of data are compared to ensure the accuracy of the satellite.

This often needs to be done at remote locations such as Lake Lefroy, a salt lake in Western Australia, due to its bright and uniform surface. Unfortunately it's a long way from any urban centres, making it a time consuming and difficult proposition to conduct regular calibrations.

Our response

Automating the calibration process

We developed an autonomous vehicle, the Outback Rover, to help scientists automate and remotely manage this process.

While it's currently in prototype stage, the ultimate goal is to have the rover operate alone, with scientists from all over the world able to retrieve data from it and control it remotely in real-time.

As well as ensuring the accuracy of the current suite of space travelling cameras and sensors, the information collected by the rover could also be used for the next-generation of satellites that will use high-resolution hyperspectral images.

These satellites will be able to collect more detailed data, including information about dry and woody plant materials and specific mineralogical data that cannot be measured with current operational satellites.

The results

Making the process simple

By automating and being able to remotely manage the satellite calibration process, scientists across the world will be able to spend more time focusing on the important data collected by the satellites, such as where to explore for mineral deposits and the current state of a particular patch of soil.

[Music plays. CSIRO logo and text appears: Satellites Keeping an eye on mining and agriculture]

[Image of a computer generated rocket taking off appears on screen and then changes to different satellites orbiting Earth]

Narrator: Thousands of kilometres above the Earth's surface hundreds of satellites are providing information to decision makers, informing how we manage mineral exploration, farming practices and environmental protection.

[Image changes to a computer generated Earth with the names and locations of the satellites marked out on it]

In fact, there are at least 60 current Earth observation programs in federal and state governments, estimated to be worth approximately 950 million dollars.

[Image changes to show researchers standing together looking skyward. One is operating a spectrometer]

CSIRO researchers recently teamed up with fellow scientists from Japan, China, Israel and France to head into the outback to make sure the information coming from those satellites is accurate. It's a process called vicarious calibration.

[Image changes to Dr Cindy Ong, Research Group Leader CSIRO]

Dr Ong: In Australia we are a huge consumer of observation data for all sorts of things, from mineral exploration to environment and so knowing that the data is well calibrated then ensures that the downstream product is a good product.

[Image changes to show the outback and a researcher operating a spectrometer]

Narrator: And how is this information calibrated? Using a spectrometer like this one, the team can take on ground measurements of surface reflection at the same time as a satellite does an overpass to take the same measurement. The two sets of data are then compared.

Another challenge for researchers who rely on satellite data is finding a suitable location to take such measurements.

[Camera is panning over Lake Lefroy]

Dr Ong: So we use targets such as this, which is Lake Lefroy a big salt lake, which is actually considered a uniform target. Uniform in terms of flat spectrally as well as uniform composition, so it's a big expanse of salt lake and it's a bright, reflectance target.

Narrator: But the problem with this Western Australian target is that it's a long way from any major urban centre. Cue Rover.

[Rover, a small robotic machine, appears from the left hand side of the screen]

CSIRO scientists have developed a prototype to see if they can automate the process of vicarious calibration.

[Image changes to Dr Alberto Elfes, Research Group Leader CSIRO who is standing behind Rover] Dr Elfes: So this vehicle could, potentially, be operating here alone and then the scientists that are interested in the data could be in their home countries in real time looking at the data that is being collected and then suggesting, for example, changes.

[Image changes to a zoomed in shot of Rover on the move]

You know, 'I need the robot to go back there'. Or 'there was this signature here, which was interesting; we need to do a more detailed analysis here'.

[The camera pans over the different parts of Rover]

Narrator: As well as ensuring the accuracy of the current suite of spaceborne sensors, the information collected on this mission will also be used for future satellites.

[Satellite images of farmland with an analysis chart appear on a computer monitor]

The next generation will be using hyper-spectral images, essentially, collecting higher spectral resolution imagery, collecting important information such as dry woody plant materials and specific mineralogical information that is not available with the current satellites.

[Image changes to Dr Ian Lau, Project Leader CSIRO

Dr Lau High spectral imagery is often used by the mining industry for exploring for mineral deposits. We have the ability to look for minerals from airborne imagery on spaceborne imagery and that gives indications of whereabouts we can explore for finding targets.

[Image changes to researchers around a map and then to a shot of an open pit mine]

A lot of money is spent in exploration on drilling and it's very expensive to put holes in the ground, so if we can improve the targeting of those drill holes by looking for mineral deposits, using remote sensing techniques where we can cover a large area, that can really be a benefit to the mining industry.

[Image changes to Professor Eyal Ben Dor, Tel Aviv University]

Prof Eyal Ben Dor: You will be able to actually monitor soil pollution, soil activity and also help farmers to fertilise the soil according to the exact amount of fertilisers, not to put more and waste money and not to put less and then reduce the productivity of the soil.

[Image has changed back to Rover on the move and then to a computer generated satellite orbiting the Earth]

Narrator: Australia doesn't have any of its own satellites, but relies on international collaborations, like this, for Earth observation data. Our collaboration with international satellite providers and the Australian government agencies like GeoScience Australia helps to ensure more accurate data, leading to efficient, productive and profitable mining and agricultural industries.

[Credits: Special Thanks To: Prof Eyal Ben Dor – University of Tel Aviv, Israel. Dr Hirokazu Yamamoto – National Institute of Advanced Industrial Science and Technology, Japan. Dr Guo Hailiang – Chinese Academy of Sciences – China. Dr Véronique Carrere – Université de Nantes, France. Filmed and Edited: Adam Harper. Music: Dan-O at]

[Music plays and CSIRO logo appears with the text: Big ideas start here]

Outback rover

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