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GPS/INS

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


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Journal ArticleDOI
TL;DR: The focus of this study is to quantitatively analyze the degradations in position accuracy in the presence of various limitations or constraints, which can be brought on by mission hardware limitations, for example, on micro- or nanosatellites.
Abstract: The combination of GPS measurements and high-fidelity dynamic models via a Kalman filter/smoother, known as the reduced dynamic technique, allows 3D positioning of Low Earth Orbiters to the sub-decimeter level. Such accuracies can only be achieved if the GPS data are nearly continuous, post-processed and a dual-frequency receiver is utilized. The focus of this study is to quantitatively analyze the degradations in position accuracy in the presence of various limitations or constraints, which can be brought on by mission hardware limitations, for example, on micro- or nanosatellites. The constraints explored in this study are as follows: the use of single-frequency data only; real-time processing; limited dynamic modeling due to computing capabilities; and non-continuous GPS receiver operation due to power limits. The experiments are conducted with 6-h data arcs for 7 separate days using data from the CHAllenging Mini-Satellite Payload. A 3D root mean square (rms) error of 15 cm is observed in the best-case solution, in which dual-frequency data are post-processed with all available data. Various levels of accuracy degradations are observed as constraints are placed on this best-case solution. The 3D rms error of the post-processed, single-frequency solution is 68 cm and 1.3 m for the real-time, dual-frequency solution. In very challenging environments, for example, with the receiver on for only 10 min of a 90-min orbit, the 3D rms increases to 350 m.

15 citations

Journal ArticleDOI
TL;DR: Decentralized integration of global positioning system (GPS), synthetic aperture radar (SAR), and terrain referenced navigation (TRN) system into an inertial navigation system (INS) is analysed in comparison to the centralized integration method in this paper.
Abstract: Decentralized integration of global positioning system (GPS), synthetic aperture radar (SAR), and terrain referenced navigation (TRN) system into an inertial navigation system (INS) is analysed in comparison to the centralized integration method in this paper. Many publications have shown different decentralized integration methods. The main advantage of the decentralized filter architecture is flexibility and modularity. Especially the federated no-reset filter has received considerable attention in literature because of improved fault detection and isolation (FDI) capability, which is an important feature in multi-sensor navigation systems. Fault detection capability of the federated no-reset filter is well-established. However, this filter type combines sensor data in a suboptimal way and a loss of accuracy compared to the centralized Kalman filter is generally observed. Other publications mentioned this loss of accuracy, but did not give the amount of accuracy loss for SAR/TRN/GPS/INS systems. In this paper additionally a slight modification of the federated filter is presented. Typically a GPS/INS filter tends to be overoptimistic due to long-term timecorrelated atmospheric errors of the GPS pseudo-range measurements. A rather simple modification of the federated filter is given to take into account this overoptimistic behaviour. A covariance correction yields a more reasonable covariance of the GPS/INS local filter and an improved overall position estimation of the federated filter.

15 citations

Journal ArticleDOI
TL;DR: The aim of the presented work is to obtain accurate direct georeferencing of camera images collected with small unmanned aerial systems by exploiting a graph optimization framework, which is designed for the least square optimization of general error functions.
Abstract: . In this paper, we present a graph based approach for performing the system calibration of a sensor suite containing a fixed mounted camera and an inertial navigation system. The aim of the presented work is to obtain accurate direct georeferencing of camera images collected with small unmanned aerial systems. Prerequisite for using the pose measurements from the inertial navigation system as exterior orientation for the camera is the knowledge of the static offsets between these devices. Furthermore, the intrinsic parameters of the camera obtained in a laboratory tend to deviate slightly from the values during flights. This induces an in-flight calibration of the intrinsic camera parameters in addition to the mounting offsets between the two devices. The optimization of these values can be done by introducing them as parameters into a bundle adjustment process. We show how to solve this by exploiting a graph optimization framework, which is designed for the least square optimization of general error functions.

15 citations

Patent
31 Dec 2008
TL;DR: In this paper, a method and apparatus for detecting bad signals at a GPS enabled device is described, which includes one or more inertial sensors to provide acceleration measurements for the GPS-enabled device, and a GPS receiver to receive positioning data for the device.
Abstract: A method and apparatus for detecting bad signals at a global positioning system (GPS) enabled device are described. In one embodiment, the GPS enabled device includes one or more inertial sensors to provide acceleration measurements for the GPS enabled device, and a GPS receiver to receive positioning data for the GPS enabled device. The GPS enabled device may also include a comparison logic to predict a position of the GPS enabled device from the acceleration measurements, and determine whether the received positioning data is within a confidence interval of the prediction.

15 citations

Proceedings ArticleDOI
20 Apr 1998
TL;DR: The Joint Direct Attack Munition provides a low-cost accuracy enhancement to existing MK-83, MK-84, and BLU-109 weapons through the use of commercial standards and high-volume production techniques.
Abstract: The Joint Direct Attack Munition (JDAM) provides a low-cost accuracy enhancement to existing MK-83, MK-84, and BLU-109 weapons. Low-cost has been achieved through the use of commercial standards and high-volume production techniques. Accuracy improvements are achieved with a GPS-aided Inertial Navigation System (INS), an adaptive optimal guidance algorithm, an autopilot featuring a robust servo structure, and a tail actuator subsystem. Flight testing has demonstrated an impact uncertainty considerably less than the 13 meter Circular Error Probable (CEP) requirement in CPS-aided missions. This paper focuses on the JDAM navigator and Kalman filter algorithms that support both GPS-aided and unaided missions. The GPS-aided navigator consists of a tightly-coupled GPS/INS integration that supports both conventional and relative GPS operation. During GPS-aided operation, the JDAM Kalman filter is configured to estimate the basic kinematics states, calibrate critical inertial sensors, estimate GPS receiver clock errors, and estimate line-of-sight biases between the weapon and each NAVSTAR satellite tracked during the mission. JDAM also includes an unaided navigation mode that is used if GPS is denied. Unaided navigation relies on a transfer alignment algorithm to align the weapon's navigator to the carrier aircraft's navigator and to calibrate critical inertial sensors before release. Transfer alignment enhancements include senescence error estimation and an adaptive Kalman filter tuning algorithm that modifies filter process noise based on the weapon's vibration environment.

15 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202317
202247
20219
202013
201925
201840