GPS/INS

About: GPS/INS is a research topic. Over the lifetime, 3554 publications have been published within this topic receiving 62784 citations.

Observability Analysis of a MEMS INS/GPS Integration System with Gyroscope G-Sensitivity Errors

Abstract: Gyroscopes based on micro-electromechanical system (MEMS) technology suffer in high-dynamic applications due to obvious g-sensitivity errors. These errors can induce large biases in the gyroscope, which can directly affect the accuracy of attitude estimation in the integration of the inertial navigation system (INS) and the Global Positioning System (GPS). The observability determines the existence of solutions for compensating them. In this paper, we investigate the observability of the INS/GPS system with consideration of the g-sensitivity errors. In terms of two types of g-sensitivity coefficients matrix, we add them as estimated states to the Kalman filter and analyze the observability of three or nine elements of the coefficient matrix respectively. A global observable condition of the system is presented and validated. Experimental results indicate that all the estimated states, which include position, velocity, attitude, gyro and accelerometer bias, and g-sensitivity coefficients, could be made observable by maneuvering based on the conditions. Compared with the integration system without compensation for the g-sensitivity errors, the attitude accuracy is raised obviously.

Integration of GPS and Strapdown Inertial Subsystems into a Single Unit

Abstract: Most GPS receivers are designed for stand-alone operation. Single-channel, slow-sequencing receivers are recognized to be lowest cost, but lack dynamic capability, while multiplexed and multichannel designs allow operation during acceleration, but add cost, weight and power. It is also well recognized that a marriage of GPS data with strapdown inertial data enhances the quality of both, and many people are looking at integration of available GPS receivers with various available inertial systems. However, direct design at the outset of a tightly integrated GPS and strapdown INS allows optimization of both for performance and cost. Using this approach, a properly designed slow-sequencing, single-channel receiver, married to a low-cost strapdown inertial unit, provides satellite tracking during 10-g acceleration, very high jamming suppression, improved strapdown inertial outputs, and improved GPS navigation accuracy. Packaging this “GPS/I” in a single unit reduces software and hardware redundancies, and results in a very low-cost design.

Adaptive Filter Design for UAV Navigation with GPS/INS/Optic Flow Integration

Abstract: An integrated system of GPS and low cost Inertial Navigation System (INS) is often used to provide position, velocity and attitude (PVA) information for navigating Unmanned Aerial Vehicles (UAV). One drawback is that such systems can not provide the ground height information during landing and terrain following tasks which is essential for safety in near ground operations. Optic flow rate measurements can be used as additional observations in the data fusion process to augment the PVA estimation. Whilst this integration scheme is effective, further research has revealed that stochastic modelling uncertainty has a significant impact on its overall performance, especially when the stochastic characteristics of optic flow measurements are hard to define. To improve the filtering performance and to cope with the stochastic modelling uncertainties, in this research a covariance matching based adaptation algorithm has been implemented with the extended Kalman filter in a loosely coupled scenario. The proposed new integration scheme is evaluated with the field data collected from a UAV platform. Test results have showed clear performance improvements.

Mapping Dilution of Precision (MDOP) and map-matched GPS

Abstract: A novel method of map matching using the Global Positioning System (GPS) has been developed which uses digital mapping and height data to augment point position computation. This method reduces the error in position, which is a sum from several sources, including signal delay due to the ionosphere and atmosphere and until recently from ‘selective availability’ (S/A). S/A was imposed by the US military to degrade purposefully the accuracy of GPS, but was switched off on 2 May 2000, and is to be replaced with ‘regional denial capabilities in lieu of global degradation’ (Interagency GPS Executive Board, 2000). Taylor et al. (2001) describe the Road Reduction Filter (RRF) in detail. RRF is a method of detecting the correct road on which a vehicle is travelling. In the work described here, the position error vector is estimated in a formal least squares procedure, as the vehicle is moving. This estimate is a map-matched correction, that provides an autonomous alternative to DGPS for in-car navigation and fleet...

Method for improving GPS integrity and detecting multipath interference using inertial navigation sensors and a network of mobile receivers

Abstract: A method for checking the integrity of GPS measurements for a moving vehicle includes determining a first inter-vehicle distance between a first vehicle and a second vehicle based on GPS measurements obtained at both vehicles, independently determining a second inter-vehicle distance based on relative motion of the first vehicle and the second vehicle obtained using INS sensors at both vehicles, and comparing the the first and second inter-vehicle distances. The integrity of the GPS measurements are checked if the first and second inter-vehicle distances are nearly equivalent. Methods for error detection and for mapping GPS multipath levels at each point in a vicinity for an entire range of satellite constellations are also described.