For large area surveillance, a number of UAVs are preferred. In such situation, navigation becomes a prime factor, which reduces the chance of collision. UAVs primarily depend on GPS, which has an order of inaccuracy. Conventional correction methods like differential GPS needs extra hardware and cannot improve stochastic errors like multipath error and receiver error. In this paper we demonstra...

The accuracy of a standard market receiver GPS (Global Positioning System) is near 10-15 meters the 95% of the times. To reach a sub-metric level of accuracy some techniques must be used [1]. This article describes some of these procedures to improve the positioning accuracy by using a low-cost GPS in a differential relative positioning way. The proposed techniques are some variations of Kalman...

With the growing demand for accurate and reliable worldwide differential GPS positioning, there has been a significant move towards the use of real-time GPS augmentation systems with wide area differential positioning capabilities. The US Wide Area Augmentation System (WAAS) and the European Geostationary Navigation Overlay system (EGNOS) are good examples of such a move. While these augmentati...

A deformation invariant representation of surfaces, the GPS embedding, is introduced using the eigenvalues and eigenfunctions of the Laplace-Beltrami differential operator. Notably, since the definition of the GPS embedding completely avoids the use of geodesic distances, and is based on objects of global character, the obtained representation is robust to local topology changes. The GPS embedd...

An entirely new sensor approach for attitude determination using Global Positioning System (GPS) signals is proposed. The concept involves the use of multiple GPS antenna elements arrayed on a single sensor head to provide maximum GPS space vehicle availability. A number of sensor element configurations are discussed. In addition to the navigation function, the array is used to find which GPS s...

As part of a project for the Defense Advanced Research Projects Agency, Sandia National Laboratones’ Intelligent Systems & Robotics Center is developing and testing the feasibility of using a cooperative team of robotic sentry vehicles to guard a perimeter, perform a surround task, and travel extended distances. This paper describes our most recent activities. In particular, this paper highligh...

This report describes the key elements and results of Stanford University’s contribution to the development of the Wide Area Augmentation System (WAAS) and its underlying technologies. The Wide Area Augmentation System (WAAS) became the first operational space based augmentation system (SBAS) in July 2003. WAAS augments the Global Positioning System (GPS) with the following three services: inte...

Kinematic differential GPS positioning is used to achieve accurate, real-time positions and velocities of a moving platform on land, in the air and at sea. In a dynamic environment, however, the deviations or biases from the assumed system and observation models are often significant. This results in a degradation of the accuracy and reliability of the estimated positions and velocities. Theref...

The modernization of the GPS and the advent of the European Galileo will enhance the capability of quickly and correctly resolving the integer cycle carrier phase ambiguities in precise differential positioning. In this paper the performances of hybrid modernized GPS and Galileo positioning are analyzed for different scenarios by using the LAMBDA method in Japan. The scenarios include modernize...

A scrutiny of the existing time differencing carrier phase (TDCP) velocity estimation algorithms has revealed several shortcomings which could be further improved. One of those is that the velocity estimation at epoch t would require the receiver positions at epoch t+Δt or more are available. Another one is the usage of satellite velocities in the calculations which would increase the receiver ...