  The transit timing variation technique (TTV) has been widely used to detect
and characterize multiple planetary systems. Due to the observational biases
imposed mainly by the photometric conditions and instrumentation and the high
signal-to-noise required to produce primary transit observations, ground-based
data acquired using small telescopes limit the technique to the follow-up of
hot Jupiters. However, space-based missions such as Kepler and CoRoT have
already revealed that hot Jupiters are mainly found in single systems. Thus, it
is natural to question ourselves if we are properly using the observing time at
hand carrying out such follow-ups, or if the use of medium-to-low quality
transit light curves, combined with current standard techniques of data
analysis, could be playing a main role against exoplanetary search via TTVs.
The purpose of this work is to investigate to what extent ground-based
observations treated with current modelling techniques are reliable to detect
and characterize additional planets in already known planetary systems. To meet
this goal, we simulated typical primary transit observations of a hot Jupiter
mimicing an existing system, Qatar-1. To resemble ground-based observations we
attempt to reproduce, by means of physically and empirically motivated
relationships, the effects caused by the Earth's atmosphere and the
instrumental setup on the synthetic light curves. Therefore, the synthetic data
present different photometric quality and transit coverage. In addition, we
introduced a perturbation in the mid-transit times of the hot Jupiter, caused
by an Earth-sized planet in a 3:2 mean motion resonance. Analyzing the
synthetic light curves produced after certain epochs, we attempt to recover the
synthetically added TTV signal by means of usual primary transit fitting
techniques, and show how these can recover (or not) the TTV signal.
