GPS/INS

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

Modular high-precision navigation system

Abstract: A modular device, system and associated method, used to enhance the quality and output speed of any generic GPS engine is provided. The modular device comprises an inertial subsystem based on a solid state gyroscope having a plurality of accelerometers and a plurality of angular rate sensors designed to measure linear acceleration and rotation rates around a plurality of axes. The modular inertial device may be placed in the data stream between a standard GPS receiver and a guidance device to enhance the accuracy and increase the frequency of positional solutions. Thus, the modular inertial device accepts standard GPS NMEA input messages from the source GPS receiver, corrects and enhances the GPS data using computed internal roll and pitch information, and produces an improved, more accurate, NMEA format GPS output at preferably 2 times the positional solution rate using GPS alone. The positional solution frequency using the present invention may increase to as much as 5 times that obtained using GPS alone. Moreover, the modular inertial device may assist when the GPS signal is lost for various reasons. If used without GPS, the modular inertial device may be used to define, and adjust, a vehicle's orientation on a relative basis. The modular inertial device and architecturally partitioned system incorporated into an existing GPS system may be applied to navigation generally, including high-precision land-based vehicle positioning, aerial photography, crop dusting, and sonar depth mapping to name a few applications.

An All-Parameter System-Level Calibration for Stellar-Inertial Navigation System on Ground

Abstract: The calibration, in particular about the installation errors of a star sensor, is a vital problem when improving the accuracy of stellar-inertial navigation system (INS). This paper proposed an all-parameter calibration method for a ground-based stellar-INS with 12-position rotations, using a Kalman filter that can simultaneously estimate bias, scale factor, misalignments of inertial measurement unit (IMU), and installation errors of star sensor. The difference between the star vector measured by the star sensor and the gold reference generated by the star simulator is used as an observation. On the basis of observability to all parameters, the accuracy is greatly enhanced through an iterative method. Better than previous separate calibration of INS and star sensor, the proposed method offers an advantage in that installation error is slightly influenced by IMU drift and device precision. The experimental results demonstrate that all estimated parameters have good stability and repeatability, with the maximum attitude error of integrated navigation less than ${6^{\prime \prime }}$ after compensation, compared with $2{0^{\prime \prime }}$ using the traditional method. It is shown that the proposed calibration method can efficiently improve the navigation performance of stellar-INS, which has been extensively used in shipborne systems, military aircraft, and missile systems.

Determination of the uav position by automatic processing of thermal images

Abstract: . If images acquired from Unmanned Aerial Vehicles (UAVs) need to be accurately geo-referenced, the method of choice is classical aerotriangulation, since on-board sensors are usually not accurate enough for direct geo-referencing. For several different applications it has recently been proposed to mount thermal cameras on UAVs. Compared to optical images, thermal ones pose a number of challenges, in particular low resolution and weak local contrast. In this work we investigate the automatic orientation of thermal image blocks acquired from a UAV, using artificial ground control points. To that end we adapt the photogrammetric processing pipeline to thermal imagery. The pipeline achieves accuracies of about ±1 cm in planimetry and ±3 cm in height for the object points, respectively ±10 cm or better for the camera positions, compared to ±100 cm or worse for direct geo-referencing using on-board single-frequency GPS.