Frequency Augmented Clock Synchronization for Space-based interferometry

Recently, an increase in distributed space systems and a rise in number of nodes in such systems is observed in numerous space applications, for example space-based interferometry. Such applications pose stringent demands on time synchronization which can be challenging to achieve for satellite networks that lack an absolute time reference...

Autonomous Mission Planning for OLFAR: A Satellite Swarm in Lunar Orbit for Radio Astronomy

Orbiting Low Frequency Array for Radio Astronomy (OLFAR) is a radio astronomy mission that has been studied since 2010 by several Dutch universities and research institutes. The mission aims at producing sky maps by collecting cosmic signals at ultra-low wavelengths regimes, below the 30 MHz frequency band. A satellite swarm comprising more than...

High Data-Rate Inter-Satellite Link (ISL) For Space-Based Interferometry

The inter-satellite link (ISL) in swarm and constellation missions is a key enabler in the autonomy of the mission. OLFAR (Orbiting Low Frequency Array for Radio astronomy) is one such mission where 10 to 50+ nanosatellites are placed in the Lunar orbit and perform astronomical observations from the far-side of the moon. Each of the...

Low-frequency observations using high-altitude balloon experiments (LOBE)

The frequency range below 30 MHz remains one of the last unexplored frequency ranges in radio astronomy However, Earth-based observations at these wavelengths are severely impeded, due to man-made radio frequency interference (RFI) and atmospheric opacity. To overcome this impediment, various space-based radio astronomy studies have been...

Efficient Calibration of Radio Interferometers Using Block LDU Decomposition

Having an accurate calibration method is crucial for any scientific research done by a radio telescope. The next generation radio telescopes such as the Square Kilometre Array (SKA) will have a large number of receivers which will produce exabytes of data per day. In this paper we propose new direction-dependent and independent calibration...

Radioastronomical image reconstruction with regularized least squares

Image formation using the data from an array of sensors is a familiar problem in many fields such as radio astronomy, biomedical and geodetic imaging. The problem can be formulated as a least squares (LS) estimation problem and becomes ill-posed at high resolutions, i.e. large number of image pixels. In this paper we propose two regularization...