Ionospheric scintillation is the physical phenomena affecting radio waves coming from the space through the ionosphere. Such disturbance is caused by ionospheric electron‐density irregularities and is a major threat in Global Navigation Satellite Systems (GNSS). From a signal‐processing perspective, scintillation is one of the most challenging propagation scenarios, particularly affecting high‐precision

Distance measuring equipment (DME) has been a cornerstone of aviation navigation for the last 70 years. While GNSS is taking an increasingly important role in civil aviation, DME can still play an important role in a robust aviation infrastructure in the foreseeable future. Advanced concepts have been developed to improve DME performance and capabilities. One concept is a DME‐based pseudolite that

The former Galileo Commercial Service (CS) will provide a High Accuracy Service (HAS) and a Commercial Authentication Service (CAS). The first will disseminate free Precise Point Positioning (PPP) corrections through the E6‐B signal whereas the second will provide authentication capabilities through the E6‐C pilot component that will be encrypted. For this reason, improved processing strategies for

In the BeiDou Navigation Satellite System (BDS) B1 band, a single‐sideband complex binary offset carrier (SCBOC) modulation is employed to combine the legacy and the modernized B1 signals into an asymmetric‐wideband composite signal for the backward compatibility. However, SCBOC modulation has only been regarded as a means to achieve the co‐existance between B1I and B1C signals, whose high‐precision

As the dependence of Global Navigation Systems (GNSS) increases, so does a growing demand for GNSS accuracy in urban environments. This research aims to improve navigation in these environments by integrating non‐line‐of‐sight signals, building models, and measured signal to noise ratios in ways not typically used in GNSS positioning. We propose a technique of combining elements of shadow matching

This research investigates the mutual interference between a GNSS signal refracted through the atmosphere and the same signal reflected from the surface below. For low‐altitude occultations, the reflected signal can be present as multipath when tracking the direct signal. This poses a problem when making remote sensing measurements using GNSS‐RO or GNSS‐R techniques. Here, this issue is addressed in

No abstract is available for this article.

This work enables GPS‐denied flight on fixed‐wing UAS by accounting for fixed‐wing‐specific sensing requirements and using a methodology called relative navigation as an overarching framework. The development of an odometry‐like, front‐end, EKF‐based estimator that utilizes only a monocular camera and an inertial measurement unit (IMU) is presented. The filter uses the measurement model of the multi‐state‐constraint

To analyze the unmodeled systematic errors in BDS, a filter‐assisted Partly Ensemble Empirical Mode Decomposition (PEEMD) method is combined with Hilbert spectrum analysis to extract the feature information from BDS preprocessed orbit determination residuals (PODR). The results show that the feature extraction method can effectively extract a period of about 1 day for GEO/IGSO satellites and a period

Binary offset carrier (BOC) modulations are widely used in the modernized satellite navigation systems. But we find an interesting phenomenon that the signal composed of different BOC modulations suffers larger phase bias than the case that all the components have the same modulation due to the nonideal group delay of the channel. This issue is more obvious in navigation satellites for the use of a

The GPS C/A‐code is the most widely utilized GNSS signal today. The C/A‐code design includes (1) a short (length‐1023) spreading code that repeats every 1 ms and (2) a low (50 bps) data rate. These two characteristics can lead to undesired interactions between received C/A‐code signals within user equipment. In this paper, a simple model is derived for predicting the impact of C/A‐code self‐interference

The US Naval Research Laboratory (NRL) has developed clock ensembles for a number of vital GNSS projects and services throughout the US and international community. Some efforts include algorithms for local realization of Coordinated Universal Time; participation in the upgrade of the Global Positioning System (GPS) system time; the initial implementation of a coherent geophysical reference time known

This paper proposes a new dual‐frequency signal deformation fault monitor, which can effectively reduce the time delay at the Ground‐Based Augmentation System (GBAS) airborne user from the airborne filter initialization to the time when it incorporates ground corrections and user measurements for navigation, assuring the system integrity at the same time. The new monitor is applied together with the

A twofold architecture based on GNSS multipath environment prediction and detection is presented in a context of loosely coupled and tightly coupled IMU/GNSS integration for navigation in urban areas. A signal quality monitoring group of techniques is applied for a platform self‐contained effort to detect and exclude multipath‐contaminated GNSS signals. Additionally, the sensor integration Kalman filter

The GPS Antenna Characterization Experiment (GPS ACE) has made extensive observations of GPS L1 signals received at geosynchronous (GEO) altitude, with the objective of developing comprehensive models of the signal levels and signal performance in the GPS transmit antenna side lobes. The GPS ACE architecture has been in place collecting observations with extreme sensitivity for several years, enabling

No abstract is available for this article.

Our objective in this paper is to assess all errors in NavIC's pseudorange so that they can be mitigated or accounted for appropriately in the dynamics model to achieve high‐accuracy navigation. Multipath errors in the L5 and S1 pseudoranges are different; hence, oscillatory multipath is removed using sidereal repeatability for these frequencies separately for accurate iono delay estimation. Iono delay

In recent years, due to the development of precise point positioning (PPP), the inconsistency of map and satellite positioning results due to crustal deformation has come to the surface. In order to solve this problem, a parameter for correcting the crustal deformation is necessary, and if it is provided as a service, the validity period and the accuracy guarantee are also necessary. In this research

This paper presents in detail an outer‐coding proposal for long GNSS messages disseminated by multiple satellites. The proposal minimizes the message reception time, or Time To Retrieve Data (TTRD), over a page erasure channel in most types of environments and visibility conditions. A message M consisting of k pages is encoded into a set C consisting of n pages, such that when any subset C ′ of C of

This study develops a three‐step Monte Carlo method to evaluate the worst possible integrity risk of ionospheric spatial gradients for GAST D GBAS. Impact simulation parameters are classified into two groups, “worst‐case” and “average,” based on the underlying integrity requirements. Unlike “average” parameters, “worst‐case” parameters are those for which a clear basis for averaging could not be established

In this work, a new time‐sequential positioning and fault detection method is developed for dual‐frequency, multi‐constellation Advanced Receiver Autonomous Integrity Monitoring (ARAIM). Unlike conventional “snapshot” ARAIM, sequential ARAIM exploits changes in satellite geometry at the cost of slightly higher computation and memory loads. From the perspective of users on Earth, the motion of any given