RTK-GPS is a real time positioning system of the accuracy of one cm order with carrier phase measurement. Many applications are now under examination in Japan. The most indispensable for the positioning procedure are carrier phase data from reference stations. There is at present a mobile radio communication system operating in Japan, called DMCA (Digital Multi-channel Access) system. It can be...

This research aims at enhancing the accuracy of land vehicular navigation systems by integrating GPS and Micro-Electro-Mechanical-System (MEMS) based inertial measurement units (IMU). This comprises improving the MEMS-based inertial output signals as well as investigating the limitations of a conventional Kalman Filtering (KF) solution for MEMS-IMU/GPS integration. These limitations are due to ...

Generally, accuracy of GPS(Global Positioning System) is higher than that of cellular network. But in tall building urban area or indoor, relatively weak GPS signal makes the positioning unstable and inaccurate. TDOA(Time Difference of Arrival) is one of the most widely used positioning methods in cellular mobile communication systems, but its accuracy is not high enough to meet the growing dem...

Results from Global Positioning System (GPS) spoofing tests against Phasor Measurement Units (PMUs) are presented, demonstrating that PMUs are vulnerable to spoofing attacks. A GPS spoofer can manipulate PMU time stamps by injecting a counterfeit ensemble of GPS signals into the antenna of the PMU’s time reference receiver. A spoofer-induced timing error of only a few tens of microseconds cause...

Nonlinear Kalman filtering methods are the most popular algorithms for integration of a MEMS-based inertial measurement unit (MEMS-IMU) with a global positioning system (GPS). Despite their accuracy, these nonlinear algorithms present a challenge in terms of the computational efficiency for portable wearable devices. We introduce a cascaded Kalman filter for GPS/MEMS-IMU integration for the pur...

This research aims at enhancing the accuracy of navigation systems by integrating GPS and Micro-ElectroMechanical-System (MEMS) based inertial measurement units (IMU). Because of the conditions required by the large number of restrictions on empirical data, a conventional Extended Kalman Filtering (EKF) is limited to apply in navigation systems by integrating MEMS-IMU/GPS. In response to non-li...

A new method of sensing the vibrational motions of a exible structure by measuring the di erence in GPS (global positioning system) carrier phase at separate antennas on the structure is presented. Differential carrier phase measurements have been recently used to determine the attitude of rigid bodies such as aircraft and spacecraft, and for aircraft landing with ground based GPS pseudolites. ...

Repeatable satellite orbits can be used for multipath mitigation in GPS-based deformation monitoring and other high-precision GPS applications that involve continuous observation with static antennas. Multipath signals at a static station repeat when the GPS constellation repeats given the same site environment. Repeat-time multipath filtering techniques need noise reduction methods to remove t...

Nowadays, GPS (global positioning system) receivers are aided by INS (inertial navigation systems) to achieve more precision and stability in land-vehicular navigation. KF (Kalman filter) is a conventional method which is used for the navigation system to estimate the navigational parameters, when INS measurements are fused with GPS data. However, new generation of INS, which relies on MEMS (mi...