GPS/INS

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

A low-cost GPS/inertial attitude heading reference system (AHRS) for general aviation applications

Abstract: An inexpensive Attitude Heading Reference System (AHRS) for general aviation applications is developed by fusing low cost ($20-$1000) automotive grade inertial sensors with GPS. The inertial sensor suit consists of three orthogonally mounted solid state rate gyros. GPS is used for attitude determination in a triple antenna ultra short baseline configuration. A complementary filter is used to combine the information from the inertial sensors with the attitude information derived from GPS. The inertial sensors provide attitude information at a sufficiently high bandwidth to drive an inexpensive glass-cockpit type display for pilot-in-the-loop control. The low bandwidth GPS attitude is used to calibrate the rate gyro biases on-line. Data collected during laboratory testing is used to construct error models for the inertial sensors. Analysis based on these models shows that the system can coast through momentary GPS outages lasting 2 minutes with attitude errors less than 6 degrees. Actual performance observed during ground and flight tests with GPS off was found to be substantially better than that predicted by manufacturer supplied specification sheets. Based on this, it is concluded that off-line calibration combined with GPS based in-flight calibration can dramatically improve the performance of inexpensive automotive grade inertial sensors. Data collected from flight tests indicate that some of the automotive grade inertial sensors (180 deg/hr) can perform near the low end of tactical grade (10 deg/hr) sensors for short periods of time after being calibrated on-line by GPS.

Analysis of Range and Position Comparison Methods as a Means to Provide GPS Integrity in the User Receiver

Abstract: Integrity is the ability of a system to let its users know whether the system is operating out of its specified performance limits This paper analyzes two receiver-based methods for assuring the integrity of Global Positioning System (GPS) signals-in-space These methods are called the range comparison method and the position comparison method Equations relating unknown satellite range errors to the quantity measured in each method are analyzed The equations reveal important characteristics of the methods, including their mathematical equivalence The performance of the two methods is derived in terms of satellite range errors Numerical results are then obtained for the performance of the methods, alone and in combination with monitoring of the receiver clock bias estimate

Fast precise GPS positioning in the presence of ionospheric delays

Abstract: In many geodetic (surveying) applications positions of points in the terrain need to be determined with high precision (cm-accuracy or even better). The Global Positioning System (GPS) is very suitable for this purpose. High positioning accuracy is in principle feasible when a relative measurement setup is used and in the processing procedure certain systematic errors in the GPS observations are properly taken into account. The largest of these errors is due to the propagation of the GPS signals through the ionosphere, the part of the atmosphere from about 80 km altitude. When the distance between the GPS receivers in the relative measurement setup is sufficiently short (e.g. a few km) it is known that these errors almost cancel, such that the positioning can be conducted using only a short time span of measurements, which is very favorable from an economical point of view. For longer distances the necessary time span increases enormously since unknown parameters for among others the ionospheric errors need to be estimated in the processing. In this thesis a procedure is outlined for the processing of relative GPS observations over medium distances (max. 50 km), while at the same time it should allow a user a short time span of measurements. An important requirement to this procedure is the availability of a permanent network of GPS reference stations. From the observations this permanent network collects, it is possible to generate information about the ionospheric delays, which a user can consequently apply to correct his own GPS observations. Much attention in the thesis is paid to the mathematical modelling aspects of this procedure.

An integrated INS/GPS approach to the georeferencing of remotely sensed data

Abstract: A general model for the georeferencing of remotely sensed data by an onboard positioning and orientation system is presented as a problem of rigid body motion. The determination of the six independent parameters of motion by discrete measurements from inertial and satellite systems is directly related to the problem of exterior orientation. The contribution of each measuring system to the determination of the three translational and three rotational parameters is treated in detail, with emphasis on the contribution of inertial navigation systems (INS) and single- and multi-antenna receivers of the Global Positioning System (GPS). The advantages of an integrated INS/GPS approach are briefly discussed

Optimal nonlinear filtering in GPS/INS integration

Abstract: The application of optimal nonlinear/non-Gaussian filtering to the problem of INS/GPS integration in critical situations is described. This approach is made possible by a new technique called particle filtering, and exhibits superior performance when compared with classical suboptimal techniques such as extended Kalman filtering. Particle filtering theory is introduced and GPS/INS integration simulation results are discussed.