A5067176836- GNSS positioning and interference
- Inertial Sensor and Navigation
- Ionosphere and magnetosphere dynamics
- Soil Moisture and Remote Sensing
- Geophysics and Gravity Measurements
- Spacecraft Design and Technology
- Precipitation Measurement and Analysis
- Advanced Frequency and Time Standards
- Wireless Communication Networks Research
- Synthetic Aperture Radar (SAR) Applications and Techniques
- Satellite Communication Systems
- Spacecraft Dynamics and Control
- Spacecraft and Cryogenic Technologies
- Target Tracking and Data Fusion in Sensor Networks
- Radio Astronomy Observations and Technology
- Space Satellite Systems and Control
- Animal Genetics and Reproduction
- Radar Systems and Signal Processing
- Astro and Planetary Science
- CRISPR and Genetic Engineering
- Underwater Vehicles and Communication Systems
- Space Technology and Applications
- Planetary Science and Exploration
- Space Exploration and Technology
- Embedded Systems Design Techniques
University of Nottingham
2020-2024
École Polytechnique Fédérale de Lausanne
2016-2017
Surrey Satellite Technology (United Kingdom)
2012-2013
University of Surrey
2007-2008
HydroGNSS (Hydrology using Global Navigation Satellite System reflections) has been selected as the second European Space Agency (ESA) Scout earth observation mission to demonstrate capability of small satellites deliver science. This article summarizes case for developed during its system consolidation study. is a high-value dual satellite mission, which will prove new concepts and offer timely climate observations that supplement complement existing are high in ESAs scientific priorities....
Global Navigation Satellite Systems (GNSS) are not only used in terrestrial applications, but also Low-Earth orbit satellites and higher altitude missions. NASA's Magnetospheric Multiscale (MMS) mission has demonstrated the capabilities of existing GNSS systems to provide positioning, navigation, timing (PNT) services Cis-lunar space. The resurgence plans by national space agencies for Lunar exploration presents a need accurate, precise, reliable navigation ensure safety success future...
A dual estimate receiver of binary offset carrier (BOC) signals for GNSS applications is described. unique derived solely from the code modulation. more accurate but ambiguous subcarrier Any time difference between two rounded to nearest subchip in order correct latter estimate. Implementation by a triple digital loop. The full potential accuracy BOC then reliably and unambiguously realised.
The integration of global navigation satellite system (GNSS) precise point positioning (PPP) and inertial (INS) is widely used in for its robustness resilience, especially case GNSS signal blockage. With modernization, a variety PPP models have been developed studied, which has also led to various PPP/INS methods. In this study, we investigated the performance real-time GPS/Galileo zero-difference ionosphere-free (IF) with application uncombined bias products. This correction was independent...
As part of the EV-2 Cyclone Global Navigation Satellite System (CYGNSS) mission team, Surrey will be providing Delay Doppler Mapping Instrument (DDMI) for eight Observatories designed and built by University Michigan Southwest Research Institute (SwRI). Following success GPS Reflectometry Experiment on UK-DMC 1 satellite launched in 2003, has developed SGR-ReSI as a move towards operational reflectometry other applications. The Space Receiver Remote Sensing (SGR-ReSI) is COTS-electronics...
Global Navigation Satellite Systems (GNSSs) were originally introduced to provide positioning and timing services for terrestrial Earth users. However, space users increasingly rely on GNSS spacecraft navigation other science applications at several different altitudes from the surface, in Low Orbit (LEO), Medium (MEO), Geostationary (GEO), feasibility studies have proved that signals can even be tracked Moon altitude. Despite this, remains a challenging operational environment, particularly...
The modernization of Global Navigation Satellite System (GNSS) including the transmission signals on multiple frequencies has greatly promoted development popular PPP (Precise Point Positioning) technique. A key issue multi-frequency is handling observable-specific signal biases in order to allow for carrier-phase ambiguity resolution (AR). As a result, modeling at user side case varies depending definition applied phase bias products. In this study, we investigate positioning performance...
In recent years, global navigation satellite system (GNSS)-based in high earth orbits (HEOs) has become a field of research interest since it can increase the spacecraft’s autonomy, thereby reducing operating costs. However, GNSS availability and GNSS-based performance for spacecraft orbiting above constellation are strongly constrained by signals’ power levels at receiver position sensitivity. The simulated level signal receiver’s may considerably or decrease when assuming different...
NAVIGATION is a quarterly journal published by the Institute of Navigation. The publishes original, peer-reviewed articles on all aspects positioning, navigation, and timing. also selected technical notes survey articles, as well papers exceptional quality drawn from Institute's conference proceedings.
Increased global dependence on Global Navigation Satellite Systems (GNSSs) has resulted in a high demand for greater precision and reliable measurements from GNSS receivers. The multipath problem is the single largest source of errors modernised GNSSs. Double differencing techniques, such as Code Minus Carrier (CMC) have been shown to accurately detect measure multipath, allowing corrections be made via Ground Base Augmentation (GBAS), example. However, these techniques require at least two...
The modernisation of GPS and the introduction Galileo will introduce use Binary Offset Carrier (BOC) modulation. BOC be implemented as either a sine or cosine sub-carrier modulation, which affects spectral properties signal receiver search, acquisition tracking processes. This paper addresses effect various forms modulation on search process. Theory is developed to draw comparisons between techniques verified with computer simulation models.
This paper discusses the new GNSS receiver architecture being designed by SSTL, and its preparation for use in space. The first application is SGR-ReSI experiment that will be flying on TechDemoSat-1 mission 2013. allow collection of GPS Reflected signals validating ocean models, also an early prototype service to notify users about wind waves. SGR-Axio advanced based upon intended replace SGR-10 low Earth orbit satellites. It has many capabilities such as multi-antenna, dual frequencies...
GNSS receivers process signals with very low received power levels (<−160 dBW) and, therefore are susceptible to interference. Interference mitigation algorithms have become common in receiver designs both professional and mass-market applications combat unintentional intentional (jamming) excision filters using fast Fourier transforms (FFTs) been proposed the past as a powerful method of interference mitigation. However, hardware implementations this algorithm mostly limited their use...
Global Navigation Satellite System (GNSS) based navigation is already adopted in Low Earth Orbit (LEO), where the presence of strong GNSS signals and good relative geometry between receiver transmitters enable precise orbit determination. However, when orbiting above constellation's altitude, designing an on-board, real-time, autonomous device poses stringent requirements. Indeed, such a challenging operational environment, signal availability as well ranging error can be significantly...
Recent studies have shown that weak Global Navigation Satellites System (GNSS) signals could potentially be used to navigate from the Earth Moon. This would increase autonomy, robustness and flexibility of navigation architectures for future lunar missions. However, utilization GNSS at very high altitudes close Moon can significantly limited by low power levels seen receiver's antenna. result in a strongly reduced visibility satellites, which worsen already poor relative geometry receiver...
As the impacts of climate change continue to increase, more and populations face risks from natural hazards such as droughts, fires flooding, monitoring which all rely on accurate timely soil moisture data. Many these areas increasing risk are located in global south, where funding for management resilient infrastructure is often low. Therefore, an open source approach especially effective - allowing action governments NGOs with tight budgets. To maximise impact this work, a fully algorithm...
With the rising incidence of Global Navigation Satellite Systems (GNSS) interference due to current geopolitical climate, Radio Frequency Interference (RFI) is among major challenges that GNSS receivers face, as it can cause significant errors in reception signals, affecting accuracy and reliability GNSS-based navigation positioning systems. Characterization mapping RFI are challenging for space applications free losses lead weak GNSS-received signals. This makes detection localization from...