Signals of opportunity navigation methods for complex lower airspace flight

Zheng, Lei; Xue, Rui

doi:10.1109/iccis.2011.6070340

Cited by 4 publications

(12 citation statements)

References 7 publications

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“…An alternative approach is to triangulate the aircraft position using existing signals originally intended for other purposes, such as those of television and cellular networks [15,16,17]. Receivers for these signals, known as Signals of Opportunity (SoOP), have a sufficiently low SWaP to be mounted on most autonomous aircraft, although the quality and quantity of the available signals varies enormously depending on the location where the flight takes place.…”

Section: Objectives and Noveltymentioning

confidence: 99%

“…Expression (17) is the observation equation with the highest influence on the estimation results as well as the least precise. It is based on the fact that the specific force measured by the accelerometers is equal to the non gravitational (aerodynamic and propulsive) accelerations, but modified as described below to minimize the negative influence of the errors present in the p n vector.…”

Section: Attitude Filtermentioning

confidence: 99%

“…The omission of the turbulence acceleration is of particular importance, as it is usually significantly bigger than the errors introduced by the accelerometer E ACC and hence one of the reasons why ÊACC can not be estimated in the attitude filter without GNSS observations. This results in (21), which only represents a middle step in the obtainment of (17) and is shown for added clarity:…”

Section: Attitude Filtermentioning

confidence: 99%

“…If GNSS signals are available, it is not necessary to eliminate the speed derivatives with time from the specific force observation equation. However, in GNSS-Denied conditions, the estimation of vN or vB in the position filter is not accurate enough, and hence its usage in (17) would introduce artificial biases resulting in a deterioration of the attitude estimation.…”

Section: Attitude Filtermentioning

confidence: 99%

“…The EKF filter itself is extremely simple and in fact can not separate between f B IB and E ACC , which are hence employed together in (17). The interesting part lies in those variables that are estimated after each filter step.…”

Section: Position Filtermentioning

confidence: 99%

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Minimization of GNSS-Denied Inertial Navigation Errors for Fixed Wing Autonomous Unmanned Air Vehicles

Gallo,

Barrientos

2021

Preprint

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This article proposes an inertial navigation algorithm intended to lower the negative consequences of the absence of GNSS (Global Navigation Satellite System) signals on the navigation of autonomous fixed wing low SWaP (Size, Weight, and Power) UAVs (Unmanned Air Vehicles). In addition to accelerometers and gyroscopes, the filter takes advantage of sensors usually present onboard these platforms, such as magnetometers, Pitot tube, and air vanes, and aims to minimize the attitude error and reduce the position drift (both horizontal and vertical) with the dual objective of improving the aircraft GNSS-Denied inertial navigation capabilities as well as facilitating the fusion of the inertial filter with visual odometry algorithms. Stochastic high fidelity Monte Carlo simulations of two representative scenarios involving the loss of GNSS signals are employed to evaluate the results, compare the proposed filter with more traditional implementations, and analyze the sensitivity of the results to the quality of the onboard sensors. The author releases the C ++ implementation of both the navigation filter and the high fidelity simulation as open-source software [1].

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Section: Objectives and Noveltymentioning

confidence: 99%

Section: Attitude Filtermentioning

confidence: 99%

Section: Attitude Filtermentioning

confidence: 99%

Section: Attitude Filtermentioning

confidence: 99%

Section: Position Filtermentioning

confidence: 99%

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Minimization of GNSS-Denied Inertial Navigation Errors for Fixed Wing Autonomous Unmanned Air Vehicles

Gallo,

Barrientos

2021

Preprint

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High-order pseudorange rate measurement model for multi-constellation LEO/INS integration: Case of Iridium-NEXT, Orbcomm, and Globalstar

Farhangian

Landry

2022

Proceedings of the Institution of Mechanical Engineers, Part G:

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An inertial navigation method augmented by Signals of Opportunity (SOPs) of three low earth orbit (LEO) constellations is presented. The downlink signal characteristics of the Iridium-NEXT, Orbcomm, and Globalstar LEO constellations are discussed. Furthermore, a tightly coupled integration model of the inertial navigation system and high-order LEO-SOP Doppler measurement model is designed. We presented a second-order measurement model of the LEO-SOP/INS integration using a second-order extended Kalman filter in which all the unknown states of the receiver and LEO satellites are estimated. The state parameters of the second-order EKF model are the position and velocity of both the receiver and the satellites, as well as the receiver’s orientation, the clock bias, and clock drift of the LEO satellites, and the constant bias of the Inertial Measurement Unit. An experiment is performed using a ground aerial vehicle equipped with a Multi-Constellation Software-Defined Receiver (MC-SDR). The Doppler measurements are provided by observing the downlinks from multiple satellites of the Iridium-NEXT and Orbcomm constellations. As well, the predicted measurement of a Globalstar satellite is used in the designed model. The results show the positioning accuracy of less than 10 m being achieved during a dynamic ground experiment, representing an 82% precision gain as compared against the regular single constellation EKF method.

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Opportunistic In-Flight INS Alignment Using LEO Satellites and a Rotatory IMU Platform

2021

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With the emergence of numerous low Earth orbit (LEO) satellite constellations such as Iridium-Next, Globalstar, Orbcomm, Starlink, and OneWeb, the idea of considering their downlink signals as a source of pseudorange and pseudorange rate measurements has become incredibly attractive to the community. LEO satellites could be a reliable alternative for environments or situations in which the global navigation satellite system (GNSS) is blocked or inaccessible. In this article, we present a novel in-flight alignment method for a strapdown inertial navigation system (SINS) using Doppler shift measurements obtained from single or multi-constellation LEO satellites and a rotation technique applied on the inertial measurement unit (IMU). Firstly, a regular Doppler positioning algorithm based on the extended Kalman filter (EKF) calculates states of the receiver. This system is considered as a slave block. In parallel, a master INS estimates the position, velocity, and attitude of the system. Secondly, the linearized state space model of the INS errors is formulated. The alignment model accounts for obtaining the errors of the INS by a Kalman filter. The measurements of this system are the difference in the outputs from the master and slave systems. Thirdly, as the observability rank of the system is not sufficient for estimating all the parameters, a discrete dual-axis IMU rotation sequence was simulated. By increasing the observability rank of the system, all the states were estimated. Two experiments were performed with different overhead satellites and numbers of constellations: one for a ground vehicle and another for a small flight vehicle. Finally, the results showed a significant improvement compared to stand-alone INS and the regular Doppler positioning method. The error of the ground test reached around 26 m. This error for the flight test was demonstrated in different time intervals from the starting point of the trajectory. The proposed method showed a 180% accuracy improvement compared to the Doppler positioning method for up to 4.5 min after blocking the GNSS.

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Signals of opportunity navigation methods for complex lower airspace flight

Cited by 4 publications

References 7 publications

Minimization of GNSS-Denied Inertial Navigation Errors for Fixed Wing Autonomous Unmanned Air Vehicles

Minimization of GNSS-Denied Inertial Navigation Errors for Fixed Wing Autonomous Unmanned Air Vehicles

High-order pseudorange rate measurement model for multi-constellation LEO/INS integration: Case of Iridium-NEXT, Orbcomm, and Globalstar

Opportunistic In-Flight INS Alignment Using LEO Satellites and a Rotatory IMU Platform

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