Add to ORKGSeveral low frequency radio astronomy arrays are currently under development. For example the LOFAR array (with 13,000 dipole elements) will operate in the frequency range of 20MHz-240Mhz. At these frequencies the effect of the ionosphere cannot be ignored. Due to the fact that the size of the array is larger than the size of the irregularities in the ionosphere the calibration problem is direction dependent and time varying. The most general form of this problem does not have a unique solution given a single sample covariance estimate. In this paper we explore several constraints derived from the physics of the problem which make the problem solvable. 1
The Low Frequency Array (LOFAR) is a novel radio telescope, operating at very low radio frequencies....
LOFAR, the Low-Frequency Array, is a powerful new radio telescope operating between 10 and 240 MHz. ...
Abstract — One of the challenges in the design of the LOFAR radio telescope is the calibration of th...
Context. New generation low-frequency telescopes are exploring a new parameter space in terms of dep...
Context. There are a number of hardware upgrades for the Low-Frequency Array (LOFAR) currently under...
The LOw-Frequency ARray (LOFAR) is used to make precise measurements of radio emission from extensiv...
The LOw-Frequency ARray (LOFAR) telescope measures radio emission from air showers. In order to inte...
To obtain high quality images with the Lofar low frequency radio telescope, accurate ionospheric cha...
We investigate systematic effects in direction-dependent gain calibration in the context of the Low-...
In recent years, science drivers have emerged for radio astronomy in the frequency range between 0.3...
Extensive air showers create short nanosecond-scale pulses in the radio frequencies. These pulses ha...
The Low Frequency Array (LOFAR) is a novel radio telescope, operating at very low radio frequencies....
LOFAR, the Low-Frequency Array, is a powerful new radio telescope operating between 10 and 240 MHz. ...
Abstract — One of the challenges in the design of the LOFAR radio telescope is the calibration of th...
Context. New generation low-frequency telescopes are exploring a new parameter space in terms of dep...
Context. There are a number of hardware upgrades for the Low-Frequency Array (LOFAR) currently under...
The LOw-Frequency ARray (LOFAR) is used to make precise measurements of radio emission from extensiv...
The LOw-Frequency ARray (LOFAR) telescope measures radio emission from air showers. In order to inte...
To obtain high quality images with the Lofar low frequency radio telescope, accurate ionospheric cha...
We investigate systematic effects in direction-dependent gain calibration in the context of the Low-...
In recent years, science drivers have emerged for radio astronomy in the frequency range between 0.3...
Extensive air showers create short nanosecond-scale pulses in the radio frequencies. These pulses ha...
The Low Frequency Array (LOFAR) is a novel radio telescope, operating at very low radio frequencies....
LOFAR, the Low-Frequency Array, is a powerful new radio telescope operating between 10 and 240 MHz. ...
Abstract — One of the challenges in the design of the LOFAR radio telescope is the calibration of th...