Dennis Odijk

Fugro World Wide | FUGRO

Knowledge of inter-system biases (ISBs) is essential to combine observations of multiple global and regional navigation satellite systems (GNSS/RNSS) in an optimal way. Earlier studies based on GPS, Galileo, BDS and QZSS have demonstrated that the performance of multi-GNSS real-time kinematic positioning is improved when the differential ISBs (DISB...

The focus of this chapter is on the models for positioning. Since the global navigation satellite system (GNSS) observation equations are nonlinear in the position coordinates, the chapter is started with a section on the linearization of the observation equations for pseudorange (code) and carrier-phase. After that, absolute (point) positioning mo...

This chapter describes the concepts of differential global navigation satellite system (DGNSS ) positioning focusing on practical details given that the fundamental concepts have been covered in prior chapters. The chapter starts with a review of the general concepts of DGNSS, including a quantitative discussion on the biases in DGNSS measurements....

The development of an Australian PPP-RTK processing platform is an important component of a multi-GNSS (global navigation satellite system) enabled national positioning infrastructure. The PPP-RTK concept extends the precise point positioning (PPP) concept by providing single-receiver users with information enabling integer ambiguity resolution, th...

The concept of integer ambiguity resolution-enabled Precise Point Positioning (PPP-RTK) relies on appropriate network information for the parameters that are common between the single-receiver user that applies and the network that provides this information. Most of the current methods for PPP-RTK are based on forming the ionosphere-free combinatio...

In this contribution we will focus on instantaneous (single-epoch) single-baseline Real-Time Kinematic (RTK) combining four CDMA satellite systems. We will combine the Chinese BeiDou, the European Galileo, the American GPS and the Japanese QZSS system. To further strengthen the underlying model and maximize the redundancy, attention will be given t...

Global Navigation Satellite System (GNSS) data from reference station networks deployed globally can facilitate positioning, navigation and timing applications. To enable precise positioning for dual-frequency users, several representative methods relying on GNSS reference networks have been developed, such as Network Real Time Kinematic (NRTK), Pr...

As in the Asian-Pacific region BDS is operational next to GPS, satellite clocks (needed for Precise Point Positioning; PPP) and satellite phase hardware biases (needed for integer ambiguity resolution enabled PPP-RTK) have been estimated from a zero baseline in Perth, Australia, and applied to dual-frequency GPS+BDS data of a single GNSS receiver a...

The BeiDou Navigation Satellite System (BDS) has become fully operational in the Asia-Pacific region and it is of importance to evaluate what BDS brings when combined with the Global Positioning System (GPS). In this contribution we will look at the short, medium and long single-baseline real-time kinematic (RTK) positioning performance. Short base...

Integer ambiguity resolution enabled Precise (cm-level) Point Positioning (PPP) is feasible if corrections from a GPS network of CORS stations are applied to the single-receiver phase and code data of a user. The concept of PPP-RTK requires a proper definition and quality of the PPP-user network corrections, which are satellite clocks, satellite ph...

The Chinese BeiDou-2/COMPASS Navigation Satellite System has attained regional operational status and is expected to reach the same level of popularity as GPS once it has reached its full constellation. This contribution considers combined BeiDou+GPS relative code positioning and single- and multiple-frequency real-time kinematic (RTK) positioning....

This contribution covers precise (cm-level) relative Global Navigation Satellite System (GNSS) positioning for which the baseline length can reach up to a few hundred km. Carrier-phase ambiguity resolution is required to obtain this high positioning accuracy within manageable observation time spans. However, for such long baselines, the differentia...

As the Chinese BeiDou Navigation Satellite System (BDS) has become operational in the Asia-Pacific region, it is of importance to better understand as well as demonstrate the capabilities that a combination of BeiDou with GPS brings to positioning. In this contribution, a formal and empirical analysis is given of the single-epoch RTK positioning ca...

Australia is a beneficiary of the current regional BeiDou configuration, as enough satellites are available for Positioning, Navigation and Timing (PNT). The present contribution is Part II out of two parts that consider first combined BeiDou+GPS results in Australia. In Part I we analysed the code-only single-receiver and relative point positionin...

China's BeiDou-2/COMPASS is expected to deliver global Positioning, Navigation and Timing (PNT) services by 2020. Australia is already a beneficiary of the regional BeiDou configuration, as enough satellites are available to perform PNT. The present contribution is Part I out of two parts that consider first combined BeiDou+GPS positioning results...

We will focus on single-frequency single-baseline real-time kinematic (RTK) combining four Code Division Multiple Access (CDMA) satellite systems. We will combine observations from the Chinese BeiDou Navigation Satellite System (BDS), European Galileo, American Global Positioning System (GPS) and the Japanese Quasi-Zenith Satellite System (QZSS). T...

In this contribution we will focus on long single-baseline real-time kinematic (RTK) positioning when combining the American GPS, Chinese BDS, European Galileo and Japanese QZSS. The main objective is to demonstrate the potential benefits for RTK when combining the next generation GNSSs, as compared to using the systems separately. With long baseli...

The Global Positioning System (GPS) and Galileo will transmit signals on similar frequencies, that is, the L1–E1 and L5–E5a frequencies. This will be beneficial for mixed GPS and Galileo applications in which the integer carrier phase ambiguities need to be resolved, in order to estimate the positioning unknowns with centimeter accuracy or better....

Results are presented of real time kinematic (RTK) positioning based on carrier phase and code (pseudorange) observations of the four Galileo In-Orbit Validation (IOV) satellites, as they were in orbit and transmitting navigation data at the time of writing this article (2013). These Galileo data were collected by multi-GNSS receivers operated by C...

High-precision (centimeter-level) real-time kinematic precise point positioning (PPP-RTK) becomes feasible when using precise corrections, as received from a regional Continuously Operating Reference Station network. These network corrections comprise (biased) sat-ellite clocks, (biased) satellite phase biases, and ionospheric delays, where the lat...

The coming decade will bring a proliferation of Global Navigation Satellite Systems (GNSSs) that are likely to enable a much wider range of demanding applications compared to the current GPS-only situation. One such important area of application is single-frequency real-time kinematic (RTK) positioning. Presently, however, such systems lack real-ti...

In this contribution, a method of isolating ionospheric delays, Satellite Phase Biases (SPBs) from a regional GPS network is presented to enable Precise Point Positioning (PPP) with rapid integer ambiguity-fixing. Experimental results based upon a reference station network whose inter-station distances range from 100 200 km demonstrate that the int...

First results are presented for precise (mm/cm-level) short-baseline RTK positioning based on single-frequency GPS data combined with data of GIOVE-A/B, the two experimental Galileo satellites, collected in Australia. The paper first focuses on the model of GPS+Galileo observation equations and addresses the issues that arise when combining data of...

The goal of Network RTK is to provide users with precise ionospheric corrections in order to conduct fast GPS ambiguity resolution and to get cm-level positioning results over medium-distance baselines. In this paper it is shown that a Network RTK user should apply the ratio test with fixed failure rate, having a threshold value that depends on the...

In this contribution, a novel un-differenced (UD) (PPP-RTK) concept, i.e. a synthesis of Precise Point Positioning and Network-based Real-Time Kinematic concept, is introduced. In the first step of our PPP-RTK approach, the UD GNSS observations from a regional reference network are processed based upon re-parameterised observation equations, correc...

Crucial to the performance of GPS Network RTK positioning is that a user receives and applies correction information from a CORS Network. These corrections are necessary for the user to account for the atmospheric (ionospheric and tropospheric) delays and possibly orbit errors between his approximate location and the locations of the CORS Network s...

As an improvement over 'conventional' PPP, Real-Time Kinematic Precise Point Positioning (PPP-RTK) is a promising technique for high-precision (cm-level) carrier-phase based remote sensing platform positioning. The key to obtain these very precise positions is that the user should be able to resolve the ambiguities in the phase data to their intege...

Global Navigation Satellite Systems (GNSS)-based attitude determination is a valuable technique for the estimation of platform orientation. Precise attitude determination using multiple GNSS receivers/antennas mounted on a remote sensing platform relies on successful resolution of the carrier phase integer ambiguities. The LAMBDA method has proven...

In the next five to ten years, the evolution of Global Navigation Satellite Systems (GNSSs) will have a revolutionary impact on the positioning performance. More GNSSs will become available with improved signal characteristics. At the same time, enhancement of receiver technology and algorithms is ongoing. In light of these developments, it is inve...

During the last decade the technique of CORS-based Network RTK has been proven capable of providing cm-level positioning accuracy for rovers receiving GNSS correction data from the CORS network. The technique relies on successful integer carrier-phase ambiguity resolution at both network and user level: at the level of the CORS network, ambiguity r...

GNSS-based attitude determination is a viable technique with a large spectrum of applications. Attitude determination requires an accurate relative positioning solution, that can be provided by the very precise GNSS carrier phase observables. The phase observables are, however, biased by unknown integer ambiguities, that must be resolved in order t...

Carrier-phase ambiguity resolution between CORS Network RTK reference stations is hampered because of the presence of differential ionospheric delays. As a consequence, after a (power) failure or when a new satellite rises above the cut-off elevation, the float ambiguity solution needs to converge before the integer ambiguities can be reliably esti...

Real-time corrections at the decimeter level over an entire continent? The challenge lies in minimizing the ranging error from signals propagating through the Earth's atmosphere. European researchers describe how it can be done using a Wide Area Real-Time Kinematic concept that exploits the full geometry of the observations, a central processing fa...

In the present contribution we study how the availability of next-generation multi-constellation Global Navigation Satellite Systems (GNSS), such as GPS and Galileo, will improve Wide Area Real-Time Kinematic (WARTK) ambiguity resolution for users receiving corrections as disseminated by the WARTK service provider. For this purpose, multi-frequency...

Cycle slips are a common error source in Global Navigation Satellite System (GNSS) carrier phase measurements. In this paper, the cycle slip problem is approached using Receiver Autonomous Integrity Monitoring (RAIM) methodology. Carrier phase measurements are used here in a single-receiver time-differential positioning method where integer ambigui...

Because of the increased call for positioning in urban areas, the performance of GNSS is analyzed under conditions with a decreased satellite visibility caused by buildings blocking the lines of sight. With GPS and Galileo almanacs and two city models visibility fi ngerprints of time-location combinations are computed. Outdoor availability and accu...

L1 phase measurements collected by a miniaturized and low cost GPS logging device are the basis for a navigation approach aiming to precisely measure (flight) trajectories independently from any auxiliary systems. Forming single differences between two measurements taken by one moving receiver at two different times allows achieving relative precis...

Successful carrier phase ambiguity resolution is the key to high-precision positioning with Global Navigation Satellite Systems (GNSS). The ambiguity dilution of precision (ADOP) is a well-known scalar measure which can be used to infer the strength of the GNSS model for carrier phase ambiguity resolution. In this contribution we present analytical...

Recently, GPS has turned into a system that is quite maturing as it continues to provide the positioning information to a wide range of civil users. This phenomenon has affected the growth of location-based applications as well as the development of the receiver technology. These receivers are based on miniaturized, low-cost modules which offers a...

Schiphol Airport in the Netherlands is one of the main airports of Europe. To improve the airport's procedures reliable and accurate positioning information is required. This paper investigates whether GPS (or in general) GNSS can provide such positioning information. Schiphol Airport is a challenging environment for satellite-based positioning, be...

Integer ambiguity resolution is a prerequisite to high-precision real-time GNSS-based attitude determination. The ADOP is a well-known scalar measure to infer whether ambiguity resolution can be expected successful or not. To compute ADOP it is sufficient to have knowledge about the measurement setup and the measurements noise characteristics; henc...

L1 phase measurements collected by an autonomous, minia- turized and low cost GPS logging device are the basis for the navigation approach discussed in the present paper. Form- ing single differences between two measurements taken by one moving receiver at two different times allows to achieve relative precision in the low decimeter range over time...

The present paper deals with precise kinematic GPS positioning applications for which requirements to the receiver such as low-cost, light weight, low power consumption and high measurement rate are becoming increasingly more important (e.g. flight maneuver reconstructions). It is investigated whether cheap and miniaturized L1 GPS receivers such as...

High precision applications of Global Navigation Satellite Systems (i.e., GPS, GLONASS and GALILEO) are based on resolution of the carrier phase ambiguities. Only if these ambiguities can be reliably resolved, secure position and/or attitude information can be guaranteed. Hence it is very important that the GNSS data are cleaned for possible model...

High-precision Global Navigation Satellite System (GNSS) positioning results are obtained with carrier phase measurements, once the integer cycle ambiguities have been successfully resolved. During the last decade much experience has been gained on fast and precise positioning with GPS as a dual-frequency system. The modernization of the GPS and th...

Sensitivity of Adop to Changes in the Single-Baseline GNSS Model The ADOP (Ambiguity Dilution Of Precision) is a measure for the precision of the carrier phase ambiguities involved in precise relative GNSS positioning. By computing the ADOP one may get knowledge in whether ambiguity resolution can be expected successful or not, already in a stage b...

This contribution presents practical results with a High-Sensitivity GPS (HSGPS) receiver in Delft, the Netherlands. One outdoor experiment was carried out on a favourable location and acts as a reference. Next, two indoor experiments were carried out, each over a 24 hour period, in a residential and in an office location. Outdoor the 95% position...

Although leveling is a very precise technique for geodetic deformation monitoring, it is quite expensive and time-consuming. InSAR is s relatively new technique in this field and has some important advantages compared to leveling: the high spatial resolution of the data and the relatively low costs of the technique. In this article both techniques...

In this contribution, optimal ionosphere-free combinations for a modernized triple-frequency global positioning system (GPS) are derived. It is shown that these ionosphere-free combinations are directly related to the model based on carrier phase observations only, in which the ionospheric delays are estimated. For this model and thus for the ionos...

 Carrier-phase ambiguity resolution is usually based on the assumption that the underlying model of observation equations is of full rank. In this contribution the model of observation equations is assumed to be of less than full rank. The well-known three-step procedure of integer least squares is generalized and it is shown how the solution can b...

Leveling surveys have traditionally been used for the geodetic monitoring of land subsidence. Although optical leveling allows for the detection of very small deformations, it is rather expensive and time-consuming. Because of the high temporal and spatial resolution versus relatively low costs, the interferometric use of Synthetic Aperture Radar (...

In GPS data processing it is not uncom-mon to eliminate the presence of ionospheric delays by taking certain linear combinations of the carrier phase data. This approach is in fact equivalent with a processing of the original, not combined, L 1 and L 2 phase observations in which the ionospheric delays are modelled as unknown parameters. When using...

In many geodetic (surveying) applications positions of points in the terrain need to be determined with high precision (cm-accuracy or even better). The Global Positioning System (GPS) is very suitable for this purpose. High positioning accuracy is in principle feasible when a relative measurement setup is used and in the processing procedure certa...

Due to the maximum of the solar cycle, ionospheric activity increased considerably last year. At frequent times warning were sent out announcing geomagnetic storms disturbing the ionospheric electron content. In this article the influence of such geomagnetic storms on fast and precise GPS positioning (for surveying applications at midlatitude regio...

Fast and high precision relative GPS positioning over distances up to 100 km is mainly limited by errors in the GPS signals due to propagation through the Earth's ionosphere. With permanent GPS arrays, which are present in many countries nowadays, it becomes possible to correct a user's GPS measurements to a certain extent for these ionospheric del...

In this article, initial results are presented of a method to improve fast carrier phase ambiguity resolution over longer baselines (with lengths up to about 200 km). The ionospheric delays in the global positioning system (GPS) data of these long baselines mainly hamper successful integer ambiguity resolution, a prerequisite to obtain precise posi...

Integer carrier phase ambiguity resolution is the key to precise GPS positioning. For baselines over 10 km the errors due to the ionosphere limit the ability to resolve the integer ambiguities within short observation time spans. Of course, one can estimate the ionospheric delays, but the additional unknowns in the model limit the use of very short...

BIOGRAPHY Dennis Odijk is a Ph.D. student at the Department of Mathematical Geodesy and Positioning of the Delft University of Technology, where he is engaged in the development of GPS data processing strategies for medium-scaled networks, with an emphasis on ambiguity fixing and modelling of the ionospheric delays. ABSTRACT The success of precise...

Both GPS and the European second generation satellite navigation system GLASS-2 or “Galileo”, are intended to transmit signals on three navigation frequencies in order to enhance ambiguity resolution performance for real-time high-precision position determination. In. this paper the performance of GPS and GLASS-2 three frequency ambiguity resolutio...

GPS ambiguity resolution is the process of resolving the unknown cycle ambiguities of double-difference (DD) carrier-phase data as integers. It is the key to fast and high-precision relative GPS positioning. Critical in the application of ambiguity resolution is its reliability. Unsuccessful ambiguity resolution, when passed unnoticed, will too oft...

BIOGRAPHY Dr. Peter Teunissen is Professor of Mathematical Geodesy and Positioning. Dennis Odijk and Peter Joosten both graduated at the Faculty of Geodesy of the Delft University of Technology. They are currently engaged in the development of GPS data processing strategies for medium scaled networks with an emphasis on ambiguity resolution. ABSTRA...

This contribution presents and discusses practical results of network-based instantaneous ambiguity resolution. It is shown that high-dimensional integer solutions can be computed efficiently with current ambiguity resolution methods. For that purpose the least-squares ambiguity decorrelation method has been integrated in the network analysis. We a...

In this contribution we introduce and analyze a measure for the GPS ambiguity dilution of precision (ADOP). In contrast to the traditional way in which DOP-measures are introduced, our ADOP is defined such that it is invariant for the class of admissible ambiguity transformations, while at the same time it captures both the precision and correlatio...

Schiphol Airport, located near Amsterdam, The Netherlands, is one of the main airports in Europe. To improve many of the dai ly processes taking place at this airport, positioning and/or navigatio n information is becoming more important. For example, both travellers and ai rline companies are interested in navigation of the traveller to his ga te....

BIOGRAPHY Sandra Verhagen obtained her PhD from and is now an assistant professor at the Delft Institute of Earth Observation and Space Systems of Delft University of Technology. Her research interests are ambiguity resolution and quality control for real-time kinematic GNSS applications. Dennis Odijk holds a PhD in Geodetic Engineering of Delft Un...

Linear combinations of the carrier phase data which are independent of the ionospheric delays are referred to as ionosphere-free linear phase combinations. In the dual frequency case there exists only one such combination which at the same time ensures the integer estimability of the ambiguities. In the triple-frequency case there is a whole class...

The Horizontal Position Error (HPE) must be no greater than the confidence bound, known as the Horizontal Protection Level (HPL), beyond the specified probability (integrity risk). The definition of protection levels is one of the keys to integrity in Satellite Based Augmentation Systems (SBAS) as the Wide Area Augmentation System (WAAS) and the Eu...

Integer carrier phase ambiguity resolution is often a prerequisite for high precision GPS positioning. It applies to a great variety of GPS models, including those which are used in hydrographic applications and marine positioning. Since the quality of kinematic GPS positioning depends critically on whether the correct integer ambiguities are used...