  This paper investigates the estimation problem of the pose (orientation and
position) and linear velocity of a rigid body, as well as the landmark
positions, using an inertial measurement unit (IMU) and a monocular camera.
First, we propose a globally exponentially stable (GES) linear time-varying
(LTV) observer for the estimation of body-frame landmark positions and
velocity, using IMU and monocular bearing measurements. Thereafter, using the
gyro measurements, some landmarks known in the inertial frame and the estimates
from the LTV observer, we propose a nonlinear pose observer on $\SO(3)\times
\mathbb{R}^3$. The overall estimation system is shown to be almost globally
asymptotically stable (AGAS) using the notion of almost global input-to-state
stability (ISS). Interestingly, we show that with the knowledge (in the
inertial frame) of a small number of landmarks, we can recover (under some
conditions) the unknown positions (in the inertial frame) of a large number of
landmarks. Numerical simulation results are presented to illustrate the
performance of the proposed estimation scheme.
