EXPANSION OF THE GRH ARRAY

Presently work is in progress to increase the size of the GRH array to about 3 km in the East-West and North-South directions making use of existing advanced techniques in signal transmission and processing. This will be Phase-I of the GRH expansion. Both the sensitivity and angular resolution of the GRH is expected to be better by a factor of two with the completion of this expansion. In Phase-II, it is proposed to increase array size to 5 km in the aforementioned directions. This will yield an angular resolution of about 1' at 150 MHz, the highest possible observing frequency with the GRH.

GRH expansion - Phase I:

                                              Array configuration of expanded GRH array Phase - I

The characteristics of the upgraded GRH – Phase I will be:[numbers for the existing array are shown within the brackets]

  • Total number of LPDs: 384 [192, 16 groups of 8 LPDs in the East- West & 16 groups of 4 LPDs in the South]
  • Frequency range: 40 – 150 MHz [40 - 150 MHz]
  • Observing time: 4 – 9 UT
  • Angular resolution: 3’ x 4’ at 150 MHz [6’ x 8’ at 150 MHz]
  • Temporal resolution: 256 ms [256 ms]
  • I.F. bandwidth: 1 MHz [1 MHz]
  • Number of spectral channels: 1 [1]
  • Effective collecting area: 192 λ² [96 λ²]
  • Point source sensitivity: 50 Jy [100 Jy] (1σ, total power mode, 256 ms integration time)
  • Number of baselines: 2016 [496] (496 E-W + 496 N-S + 1024 E-W x N-S)
  • Short / long baseline: 10.5 / 2490 m [10.5 / 1210 m] (Back end receiver: 1-bit, 2-level correlator with 4096 channels [1024])

Expansion Work Photos