the simulations and the observations. We focus on the most sensitive of the upcoming radio telescopes and carry out a detailed calculation of the prospects for making a detection using either the first phase of the SKA (SKA1-mid) or the future upgrade to SKA2.\
We begin this paper by describing the simulation and the framework we use to obtain a realistic filament signal in Section \[sec:sims\]. The strategy that will be adopted for observations is laid out in Section \[sec:obsstrat\]. Then estimates for observations with SKA1-mid and SKA2 will be made in Section \[sec:snr\]. Finally, some additional observational effects will be discussed in Section \[sec:interfero\]. Throughout the paper we adopt the @art:planck14 cosmological parameters, which are consistent with the latest  @art:planck18para parameters within the errors.

The HI 21cm signal from simulations {#sec:sims}
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In this section we provide a description of the simulation that is used to determine a realistic filament signal and the method that was adopted to extract filaments from the box. We then discuss the major sources of uncertainty for such an estimate.

The EAGLE simulation box {#sec:simbox}
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The Evolution and Assembly of GaLaxies and their Environments (EAGLE) suite of simulations includes heating due to shocks 