The Di erential Global Positioning System-based precision approach and landing architectures proposed by the Federal Aviation Administration (FAA) include the Wide Area Augmentation System (WAAS) and the Local Area Augmentation System (LAAS) for performing landings in Category (CAT) I and CAT III minima, respectively. The Required Navigation Performance (RNP) for GPS-based satellite navigation ...

One of the most widespread applications of the Global Positioning System (GPS) is vehicular navigation. Improving the navigation accuracy continues to be a focus of research, commonly answered by the use of additional sensors. A sensor commonly fused with GPS is the inertial measurement unit (IMU). Due to the fact that the requirements of commercial systems are low cost, small size, and power c...

Accuracy and robustness are vital to present and future air navigation, both in the military and civil spheres. The strengths of INS and GPS are well known; integrated INS/GPS systems combine their advantages. However, the knowledge required to jam GPS is becoming public, and it can be carried out with basic hardware. When GPS data are unavailable, and a low grade INS is used, navigation accura...

NAVSYS Corporation has modified its software GPS receiver (SGR) and built an engineering development unit of the High-gain Advanced GPS Receiver (HAGR) optimized for GPS tracking in an orbital environment. Enhancements to the SGR include the ability to track both direct GPS signals, as well as weaker GPS sidelobes. This requires digital beam steering and beam nulling to increase gain towards th...

In both military and civilian applications, the inertial navigation system (INS) and the global positioning system (GPS) are two complementary technologies that can be integrated to provide reliable positioning and navigation information for land vehicles. The accuracy enhancement of INS sensors and the integration of INS with GPS are the subjects of widespread research. Wavelet de-noising of I...

In this paper, we propose a cost-effective localization solution for land vehicles, which can simultaneously adapt to the uncertain noise of inertial sensors and bridge Global Positioning System (GPS) outages. First, three Unscented Kalman filters (UKFs) with different noise covariances are introduced into the framework of Interacting Multiple Model (IMM) algorithm to form the proposed IMM-base...

NAVSYS High Gain Advanced GPS Receiver (HAGR) uses a digital beam-steering antenna array to provide additional gain in the direction of the GPS satellite signals. This increases the received signal/noise ratio on the satellites tracked and also improves the accuracy of the pseudo-range and carrier-phase observations. The directivity of the digital beams created from the antenna array also reduc...

Ionospheric scintillation degrades GPS positioning accuracy in a number of ways. Along each scintillating satellite-receiver link, errors are introduced in the measurements of pseudorange and carrier phase. When the scintillation on a given link is sufficiently intense, the link becomes intermittently unavailable for use in the position solution. The loss of each link leads to an increased dilu...

This document is disseminated under the sponsorship of the Department of Transportation, Federal Aviation Administration, in the interest of information exchange. The United States Government assumes no liability for its contents or use thereof. The U.S. Federal Aviation Administration is deploying Automatic Dependent Surveillance-Broadcast (ADS-B) to provide next-generation surveillance derive...

Signal in space (SIS) errors are a major error source for the Global Positioning System (GPS). They are defined as any errors related to satellite transmission, mainly satellite position and clock errors. A better understanding and characterization of the signal in space errors are essential for GPS integrity, because the SIS errors are a metric to determine satellite outages or failures. The s...