Forward Modeling the DSA-2000 Radio Camera

Currently under development, the DSA-2000 will be a 2000-antenna radio interferometer operating in the 0.7-2 GHz band, with a design highly optimized for surveys. A physics-informed end-to-end forward model of the instrument from true sky through to visibility data is the fundamental basis for the hardware and software requirements for the DSA-2000. Our forward model consists of a realistic sky model, a coherent simulation of the ionosphere, per-antenna receiver patterns, antenna pointing offsets, electronic gains, and radio frequency interference. The wide field of view (~10 sq deg) and the large number of antennas of the array pose significant computational challenges to the forward model. To efficiently model the direction-dependent effects, we adopt a novel hybrid of A-projection and discrete Fourier transform algorithms to respectively capture the faint and bright source populations. We will show simulated observations and discuss implications for the design of both the antenna and the radio camera digital backend for the telescope.