Comparison of User Coordinate Estimation Accuracy for ToF and ToF/AoA Local Navigation Systems Integrated with an Inertial Measurement Unit

Today, in addition to local navigation systems and global navigation satellite systems, there are other navigation sensors and systems (inertial, odometric, etc.) that solve the same or similar tasks of navigation support. One of the methods to improve the positioning accuracy of local navigation systems is its integration with other both radiotechnical and non-radio-technical sensors. This paper is devoted to the development of algorithms for complexing the inertial measurement unit with ToF and ToF/AoA local navigation systems. The synthesized algorithm is based on quasi-optimal filtering in the Gaussian approximation of the posterior probability density function. The study was conducted using simulation modeling. For each ToF/AoA and ToF architecture, the same trajectory was specified. In the case of the ToF architecture, the motion was modeled inside the LNS working area, while in the ToF/AoA architecture, the user was always in the upper half-plane. As a result of modeling for the ToF/AoA architecture, the RMS of the coordinate estimates in the horizontal plane was 3.56 cm and 1.58 cm, for the $T 0 F$ architecture $\mathbf{- 1 . 4 2} \mathrm{cm}$ and 0.79 cm. The RMS of the velocity vector components for the ToF/AoA architecture was $1.01 \mathrm{~cm} / \mathrm{s}$ and $0.38 \mathrm{~cm} / \mathrm{s}$, for the $T 0 F$ architecture $0.49 \mathrm{~cm} / \mathrm{s}$ and 0.25 $\mathrm{cm} / \mathrm{s}$, respectively.