Deep-space radio system could boost satellite communication

Satellites orbiting other planets could communicate with Earth up to 20 times faster using a new deep-space radio system from BAE Systems.

The technology, developed in anticipation of a European Space Agency (ESA) tender, could help cut the costs of monitoring multiple deep-space craft and allow authorities to track them more accurately.

This could allow vehicles to make more precise calculations about the gravity and mass of planets and moons and even help to verify Einstein’s general theory of relativity.

Nick James, BAE’s lead engineer on the project, told The Engineer that being able to receive data more quickly would enable several distant spacecraft to be monitored at the same time.

‘If there are multiple spacecraft around Mars — for example, a couple of US ones and a European one — to save money in the future it’s likely the agencies will share support,’ he said.

Using equipment that can demodulate data from all three spacecraft at once will cut costs because only one agency will need to monitor the signals at any time, added James.

The prototype technology improves on BAE’s intermediate frequency modem system (IFMS), developed in the late 1990s and since used to receive very weak radio signals from spacecraft at ESA ground stations.

It works by converting the analogue radio signal into a digital one, processing it with a high-speed digital filter and then using software to remove background noise.

The new system increases the speed or sampling rate of both the analogue-to-digital converter (ADC) and the digital filter, which determines the maximum bandwidth of data the technology can process.

‘It is this latter sampling rate that is the really important one,’ said James. ‘This has gone from 35MHz to 700MHz. So we can say that the new receiver is 20 times faster [or more powerful] than the old one.’

BAE expects the ESA to put out a call for a new communications system this year, in advance of the IFMS’s end of life in 2015.

As well as the faster sampling rate, the ESA is likely to be looking for a reduction in lifetime costs of about 50 per cent and operation over a much wider range of radio frequencies.

James said the BAE equipment could receive signals with a frequency of up to 1.8GHz, covering much of the radio spectrum from long-wave to mobile-phone signals.

This is possible because of the faster sampling rate of the ADC, which BAE has increased from 280MHz to 2.1GHz — a factor of eight.

Like the original IFMS, the new technology will also be reconfigurable as new software is developed, prolonging the life of the equipment and allowing it to speak with different spacecraft on demand.

James would not reveal how much the project was worth to BAE or how much had been invested in the prototype device, but he did say that the long-term cost of the IFMS was around £12m over 10 years.