Projects

The Fourier Space team has developed precision, highly parallel radio astronomy instrumentation for facilities spanning the Parkes radio telescope to the Square Kilometre Array.

Fourier Space’s ability to digitally capture multiple high bandwidth data streams that it can filter and tune to any frequency/bandwidth combination delivers novel solutions for the Sat Comm sector. In our first commercial deployment we delivered a receiver capable of processing several GHz of bandwidth to deliver.

Our team designed and commissioned the 64-dish MeerKAT telescope Pulsar Timing Processor that was commissioned in 2019 and used by the MeerTime Large Survey Project to observe radio pulsars. The instrument can coherently dedisperse 875 MHz of dual-polarisation bandwidth and produce both full Stokes folded profiles, search mode data and baseband captures. Observations of PSR J2241-5236 set new records on the jitter limit (4 ns/hr) and observations of the double pulsar were able to demonstrate light bending around the companion. In the first four years of operation over 30,000 observations of pulsars were recorded.

Inputs: 4 independently controlled, dual polarisation, tied array beams produced by the MeerKAT beamformer. Each beam is encoded in 8-bit SPEAD UDP format split into 1024 or 4096 critically sampled channels. The tied-array beams are configurable at different bandwidths for each receiver: UHF (544 – 1088 MHz), L-Band (856 – 1712 MHz) or S-Band (1969-2845 MHz). The maximum required data acquisition rate for each tied-array beam is 28 Gb/s, or 112 Gb/s across all 4 beams,

Hardware: 4 servers, 1 per tied-array beam, each equipped with 40Gb NIC, RTX 2080Ti GPUs, 4×2 TB NVME RAID, 6x8TB SATA RAID

Processing: Each beam is independently controllable, supporting 3 observing modes

• Pulsar Timing: coherent de-dispersion and folding using DSPSR forming PSRFITS folded archives
• Filterbank: formation of PSRFITS search mode filterbank files with operational coherent dedispersion
• Baseband: record the raw voltages from the beam-former for a maximum of 20 minutes.

The first multibeam polyphase filterbank pulsar search solution deployed at Parkes led to the discovery of the cosmological population of Fast Radio Bursts (FRBs) by the High Time Resolution Survey teams and also real-time FRB discoveries that revealed their polarimetry. Fourier Space’s data capture engine fills ring buffers that can be searched in real time and trigger either voltage capture or detected filterbanks for offline analysis. These have led to the discovery of 100s of radio pulsars.

Faced with almost 4 GHz of bandwidth the CSIRO used Fourier Space’s data capture and pulsar processor to upgrade their pulsar observing system in 2020. Our solution coherently dedisperses the entire band for pulsar timing and polarimetry. The system also doubles as a pulsar search and Fast Radio Burst instrument, and using our flexible libraries produces high resolution spectra for spectroscopy. 

Inputs: 26 dual polarisation, 128 MHz coarse channels at 16-bits per sample, package into VDIF format. The channels span 704 – 4032 MHz.

Hardware: 9 servers, each equipped with 2 CPUs, dual 40Gb NICs, 4 GTX Titan X GPUs, 128 GB DDR3 memory and 3 SSDs configured in a RAID volume.

Processing: Each coarse channel can be processed with multiple observing modes:

• Pulsar Timing: coherent de-dispersion and folding using DSPSR forming PSRFITS folded archives
• Pulsar Search: formation of PSRFITS search mode filterbank files with operational coherent dedispersion
• Continuum: channelisation to 262144 fine channels, integrated into SDHDF files.
• VLBI: form output VDIF voltage channels at 2, 4 or 8 bit sampling at a range of bandwidths.
• Baseband: record quantised raw voltages to disk in PSRDada file format.

In one of Fourier Space’s most demanding projects, our team has developed the data capture and pulsar/FRB search instrument that can capture a range of data products from the CSIRO Beam Former spanning 72 dual-polarisation beams from the CSIRO’s phased array feed (PAF).

Inputs:

The initial deployment of this CryoPAF will provide 307 MHz of bandwidth, which will be progressively increased to 921 MHz in staged releases. The beam-former will generate several tied-array beam data streams, using the CODIF data format, that will be processed by the signal processor:

• Voltage Inputs: 8 dual-polarisation beams, channelised into ~14.8 kHz voltage channels, oversampled at 32/27 and quantised at 16-bits. The maximum data rate that will be acquired will be 280 Gb/s.
• High Time Resolution: 72 detected, full-polaristaion (4) beams, with 3456 channels (267 kHz resolution) and ~57 microsecond sampling. This data stream will be used pulsar surveys and fast radio burst science, producing a maximum data rate of 140 Gb/s.
• High Frequency Resolution: 72 detected, full-polaristaion (4) beams, with 3359232 channels (274 Hz resolution) and ~1 second sampling. This data stream will be used continuum, galactic and extra-galactic science, producing a maximum data rate of 3.6 Gb/s.

Hardware: 6 servers, each equipped with 2 100Gb Mellanox NICs and 4 A10 GPUs that are connected via 100Gb switching infrastructure.

Processing: The Signal Processor is configured to produce different science data products for the different inputs, namely:

• Voltage Beams: rechannelise the fine frequency channels using Polyphase Filterbank Inversion to wider voltage channels:
  • VLBI: form quantised (2, 4 or 8 bit) VDIF data streams.
  • Pulsar Timing: perform coherent de-dispersion and folding using DSPSR forming PSRFITS folded archives
  • Spectrometer: form ultra-high resolution spectra in SDHDF data products.
• High Time Resolution: process the input data streams to form data streams with configurable bit depths, temporal and spectral resolutions:
  • Pulsar Survey: Pulsar formation of PSRFITS search mode filterbank streams
  • Fast Radio Burst: execute real-time fast radio burst searches
• High Frequency Resolution: process the input data streams to form data streams with configurable temporal and spectral resolutions
  • Continuum: form SDHDF data products across the entire bandwidth with frequency resolution of 533 kHz.
  • Galactic: form windowed SDHDF data products with frequency resolution of 274 kHz.
  • Extra-Galactic: form windowed SDHDF data products with frequency resolution of 14.8 kHz.

Our team designed the Square Kilometre Array pulsar processor, 16 of which will be deployed at both the Australian and South African sites. We are currently part of the SKA SAFE teams that will produce this inspiring instrument in the late 2020s. These instruments will be capable of coherently de-dispersing over 1 GHz of bandwidth in real time for timing and searching applications.

Inputs: 16 independent, dual-polarisation tied-array beams channelised into over-sampled, fine frequency channels

• Low Telescope: 300 MHz of bandwidth, with 4/3 oversampling, channelised into 82944 fine channels, with 207.36 microsecond sampling. The total data rate for all 16 beams is 409.6 Gb/s
• Mid Telescope: 2500 MHz of bandwidth, with 8/7 oversampling, channelised into 46503 fine channels, with 53.76 micrsecond sampling. The total data rate for all 16 beams is 1462.9 Gb/s

Hardware: 16 servers, each equipped with 2 100Gb Mellanox NICs and Nvidia GPUs that are connected via 100Gb switching infrastructure.

Processing: Each coarse channel can be processed with multiple observing modes:

• Pulsar Timing: coherent de-dispersion and folding using DSPSR forming PSRFITS folded archives
• Pulsar Search: formation of PSRFITS search mode filterbank files with operational coherent dedispersion
• Baseband: record quantised raw voltages to disk in PSRDada file format.
• VLBI: form output VDIF voltage channels at 2, 4 or 8 bit sampling at a range of bandwidths.