Using Perspective-n-Point Algorithms for a Local Positioning System Based on LEDs and a QADA Receiver

Abstract

The research interest on location-based services has increased during the last years ever since 3D centimetre accuracy inside intelligent environments could be confronted with. This work proposes an indoor local positioning system based on LED lighting, transmitted from a set of beacons to a receiver. The receiver is based on a quadrant photodiode angular diversity aperture (QADA) plus an aperture placed over it. This configuration can be modelled as a perspective camera, where the image position of the transmitters can be used to recover the receiver’s 3D pose. This process is known as the perspective-n-point (PnP) problem, which is well known in computer vision and photogrammetry. This work investigates the use of different state-of-the-art PnP algorithms to localize the receiver in a large space of 2 × 2 m2 based on four co-planar transmitters and with a distance from transmitters to receiver up to 3.4 m. Encoding techniques are used to permit the simultaneous emission of all the transmitted signals and their processing in the receiver. In addition, correlation techniques (match filtering) are used to determine the image points projected from each emitter on the QADA. This work uses Monte Carlo simulations to characterize the absolute errors for a grid of test points under noisy measurements, as well as the robustness of the system when varying the 3D location of one transmitter. The IPPE algorithm obtained the best performance in this configuration. The proposal has also been experimentally evaluated in a real setup. The estimation of the receiver’s position at three particular points for roll angles of the receiver of γ={0°, 120°, 210° and 300°} using the IPPE algorithm achieves average absolute errors and standard deviations of 4.33 cm, 3.51 cm and 28.90 cm; and 1.84 cm, 1.17 cm and 19.80 cm in the coordinates x, y and z, respectively. These positioning results are in line with those obtained in previous work using triangulation techniques but with the addition that the complete pose of the receiver (x, y, z, α, β, γ) is obtained in this proposal.

Visible Light Positioning as a Next-Generation Indoor Positioning Technology: A Tutorial

“…It is clear that angular information can be obtained in many different ways, depending on the transmitter and receiver configuration. Various receiver topologies have been proposed: orthogonal receivers [393], tilted receivers [394], [395], circular receivers [396], aperture-based square [397] and circular [398] quadrant receivers, etc. An alternative approach to AoA estimation relies on the usage of a liquid crystal display in front of the photodiode, acting as an adaptable angular filter, only being transparent for specific angles of incidence at the photodiode [399].…”

Advances in Indoor Positioning and Indoor Navigation

“…Light is also used by Aparicio Esteve et al [ 13 ]. They propose an indoor local positioning system based on LED lighting, transmitted from a set of beacons to a receiver.…”

Pose Estimation for Visible Light Systems Using a Quadrature Angular Diversity Aperture Receiver

“…The paper [ 13 ] that focuses more on the communication aspects considers the effect of a tilt angle, which restricts the orientation to two degrees of freedom. Recently, the work [ 14 ] studied the joint 3D position and 3D orientation estimation, namely pose estimation, based on a classic non-iterative perspective-n-point (PnP) algorithm, a well known algorithm for camera sensors in computer vision. In their work, to employ the PnP, first the light spot center is obtained based on the RSS.…”