Nonlinear Observers for GNSS- and Camera-Aided Inertial Navigation of a Fixed-Wing UAV

Abstract

Abstract-In this paper, exponentially stable non-linear observers for estimation of position, velocity, specific force, attitude and gyro bias of a fixed-wing unmanned aerial vehicle (UAV) are proposed. The sensor suite consists of an Inertial Measurement Unit (IMU), a global navigation satellite system (GNSS) receiver, a camera, an altimeter, and, possibly, auxiliary roll and pitch measurements. A first observer is designed making use of all the named sensors and is proven to be globally exponentially stable (GES). Subsequently, the auxiliary roll and pitch measurements are removed and replaced by an additional feedback loop from the estimated attitude, and the new observer is analysed and proven to be uniformly locally exponentially stable (ULES). An optical flow algorithm is used to calculate the UAV velocity based on the camera images, which is used as a measurement of the body-fixed velocity in the attitude observer. The performance of the observers is tested offline on simulated and experimental data.

Flying Chameleons: A New Concept for Minimum-Deployment, Multiple-Target Tracking Drones

“…High seas search and rescue missions are a good example [ 28 , 29 , 30 ], where people and/or small boats adrift at sea after shipwrecks or other disasters need to be tracked as closely and continuously as possible, in order to assess the prioritization strategy for rescue teams. Another example is surveillance missions involving suspicious vessels [ 31 ]. It is common that, for instance, smugglers or illegal migration mafias coordinate the simultaneous departure of several vessels, including even decoy vessels, making it harder to detect or track all of them.…”

A Global Interconnected Observer for Attitude and Gyro Bias Estimation with Vector Measurements

“…The first two assumptions are standard assumptions in attitude estimation; see, e.g., [ 12 , 13 , 17 , 20 ]. Assumption 1 is necessary to guarantee uniform observability.…”

“…After that, they came up with an alternative semi-global attitude observer in the unit quaternion space [ 13 ] by employing the theory of cascaded linear and nonlinear system observers, which appeared in [ 14 , 15 ]. For obtaining globally stable observers, some studies adopt the topological constraint lifting methods before estimating the attitude rotation matrix, such as Batista et al [ 16 , 17 ], Grip et al [ 9 , 18 ], Bryne et al [ 19 ], and Fusini et al [ 20 ]; in addition, the nonlinear observers in [ 18 , 19 , 20 ] are all based on extensions or various applications of the observer in [ 9 ]. Among these observers, except the observer in [ 16 ] attained global asymptotical stability; others achieved global exponential stability.…”

A Robust INS/SRS/CNS Integrated Navigation System with the Chi-Square Test-Based Robust Kalman Filter

“…However, the gyro drift and accelerometer bias lead to unbounded error growth in the INS [ 5 ]. In order to overcome this shortcoming, the inertial navigation system/global navigation satellite system(INS/GNSS) integrated navigation system has been investigated [ 6 , 7 , 8 ]. However, the GNSS relies on signals from artificial satellites, and therefore lacks autonomy and is susceptible to artificial interference [ 9 ].…”