Nonlinear state estimation for inertial navigation systems with intermittent measurements

Nonlinear Observers for Stereo-Vision-Aided Inertial Navigation

“…Typically, the attitude can be estimated using body-frame measurements of at least two non-collinear inertial frame vectors [6]. These bodyframe vector measurements can be easily constructed from full landmark position measurements, see for instance [23].…”

“…. These geometric estimation errors are motivated from [1], [15], [23], and are different from the standard errors used in classical EKF-based filters [2], [3]. The innovation term σ R in (7) can be rewritten as…”

“…This assumption implies that the time difference between two consecutive vision-based measurements are lower and Motivated by the work in [23] and making use of the framework of hybrid dynamical systems presented in [35], [36], we propose the following hybrid nonlinear observer modified from (6) aṡ 7, and the vector σ y is given in (11) for stereo-bearing measurements and in (13) for monocular-bearing measurements. Let K :…”

“…Hence, the same conditions as in Lemma 2 and 3 can be derived for the existence of the positive constants µ ∈ R and δ ∈ N >0 such that W h o (t j , t j+δ ) > µI 15 for all j ∈ N >0 . In view of (3), (7) and (23), one obtains the following hybrid closed-loop system H:…”

“…where the AGAS proof for the equilibrium (I 3 , 0 15×1 ) of H can be easily conducted by combing the proof of Theorem 1 and [23,Theorem 9], and is therefore omitted here. The proposed hybrid nonlinear observer for vision-aided INSs with intermittent vision-based measurements has been summarized in Algorithm 1.…”