One of the most significant issues in hydrography today is the use of the ellipsoid as a vertical reference for surveying measurements. High-accuracy GPS is used to vertically position hydrographic data collection platforms, relating bathymetric observations directly to the ellipsoid. Models are used to translate those observations to another datum. The use of high-accuracy vertical GPS and translation models to replace traditional tidal correctors is relatively new to the hydrographic community and, as such, requires some discussion. Even though individual components of the process are well understood in their particular field, it is their amalgamation and application to hydrography that requires explanation, clarification and evaluation.Many hydrographic organizations around the world are using Global Navigation Satellite Systems (GNSS) derived heights in their data collection and processing stream. The International Federation of Surveyors (FIG) has recognized the importance of these new developments and has established a new working group under Commission 4, tasked to developing best practices for Ellipsoidally Referenced Surveys (ERS). Over twenty groups from academia, industry and government who are engaged in some form of ERS have provided the working group with a summary of their practices and experiences. This paper outlines the issues related to ERS and summarizes the solutions being employed.

In 2008 NAVOCEANO conducted trials to test the effectiveness of using GPS buoys for water level datum transfers. The GPS vertical positioning evaluation showed that the real-time precise point positioning solutions were not corrected for earth tide, leading to a 10 cm bias relative to three post-processing methods. Ignoring buoy tilt led to errors of up to 10 cm; however, when using 6-minute averaging, the maximum error reduced to ~2 cm. Water level transfer from a tide station 1.3 km away resulted in a datum 12 cm lower than the VDatum model estimate.

Introduction: Physician sexual boundary violations are a public health problem. Few resources exist to address physicians who behave inappropriately with patients. In response, the Center for Professional Health at Vanderbilt University developed a three-day continuing medical education (CME) course about proper professional sexual boundaries in 2000. The mission of this CME course is to offer an educational intervention for those physicians whose professional sexual misconduct has required such education as Part of a larger accountability sanction. Previous studies suggest that when such education is offered through non-traditional medical education, it is effective in promoting behavioral change. This paper describes the three-day intensive educational experience offered by a CME course with a Particular focus on lessons learned from more than 7 years of experience working with these physicians.Methods: Over 381 physicians from 40 states and Canada have attended. Data about course participants was collected by self-report and aggregated into three categories: demographics, results of assessment tools administered, and quality of the experience. Assessment tools used include the Family Adaptability and Cohesion Evaluation Scale II (FACES II), the Trauma Symptom Inventory (TSI (TM)) and the Sexual Addiction Screening Test (SAST).Results: Most physicians were referred to the course from physician health programs and boards of medical examiners. The majority of physician participants were male and in group or solo practice. A full range of medical specialties was represented with most physicians being internists, psychiatrists, obstetricians and surgeons. Results of assessment tools administered indicate that physicians referred for sexual boundary violations often come from dysfunctional families and demonstrate symptoms indicative of trauma related problems and possible sexual addiction. Physician attendees report being highly satisfied with the new knowledge attained in this course.Discussion: Curriculum aimed at addressing sexual boundary violations should address family of origin issues, trauma coping skills and sexual acting out. Satisfaction data continues to support a small group, experiential, and confidential format as an effective means for intervention.Conclusion: A CME course offers a model for future training experiences for faculty, residents, medical students and community physicians to teach skills that may help prevent and remediate professional boundary crossings.

The two remaining obstacles to long-range, high-accuracy (LRHA) GPS positioning are the errors associated with the ionosphere and the troposphere. Several models and methods have been developed to address both of these obstacles. This paper describes a method for combining L1/L2 differences with ionosphere estimates to create an improved ionosphere corrector. Traditionally, the effects of the ionosphere on LRHA positioning have been mitigated through L1/L2 ionospherefree combinations. This method almost completely removes the effect of the ionosphere; however, the resulting combined observations have an increased noise level and the integer nature of the initial carrier ambiguity is lost. The result being that the L1 and L2 integer ambiguities can not be estimated, making ambiguity fixed solutions impossible. Several ionosphere models exist that are used to estimate ionosphere errors, and can be applied to both L1 and L2 observations. In this situation the integer nature of the ambiguity is preserved, making fixed ambiguity solutions theoretically possible. However, tests have shown that the existing models tend to smooth out the high frequency localized ionosphere effects, leaving residual errors that are too high for reliable ambiguity fixing. Combining L1/L2 differences with the model error estimates provides a method for introducing the local high frequency effects into the models to reduce uncertainty. Previous test have shown that a post-processed version of the combined method gives results very comparable to the ionosphere-free solution [Dodd and Bisnath, 2006]. The tests conducted in conjunction with this paper show that a real-time version of the combined method produces results almost as good as the ionosphere-free solution, which makes it, theoretically, good enough for ambiguity resolution. The tests also show that the combined solution, regardless of the model used to produce the initial ionosphere error estimates, produces better results than those determined from any of the models alone.

The impetus for this project grew out of our involvement in tertiary teaching in science and engineering courses. Our own experiences as teachers in undergraduate and graduate science papers, and preservice science and technology education papers, had led us to debate the learning experiences of our students. We intuitively felt that there was something lacking in those experiences in terms of learning to be a scientist or an engineer, and wondered about the sense of identity that these students developed through their involvement in these papers. Research (Eames & Bell, 2005) had indicated that the learning environment in science and engineering in a university setting was quite different to that experienced in a science and engineering workplace. So, what sort of identity were these students developing? Our own anecdotal evidence pointed to a view of something disconnected from the world of science and engineering as practised in the working community.

The U.S. Coast Guard in cooperation with other federal agencies, including the Department of Transportation and the Federal Railroads Administration has begun the modernization of its highly successful Nationwide Differential Global Positioning System (NDGPS) beacon network. Aside from simply replacing aging equipment, the modernization program calls for investigations into improving the quality of the service in terms of integrity, availability, precision and accuracy.One aspect being studied is improved handling of atmospheric refraction of the incoming GPS signals. The National Geodetic Survey (NGS), Space Environment Center (SEC) and Forecast Systems Laboratory (FSL) at the National Oceanic and Atmospheric Administration (NOAA), Federal Aviation Administration (FAA) and the Jet Propulsion Laboratory (JPL) have developed ionospheric and tropospheric delay products for test areas within the continental U.S.The Hydrographic Science Research Center in the Department of Marine Science at the University of Southern Mississippi in cooperation with the Coast Guard is analyzing these data products in support of the following overall goals: to characterize the quality of the NOAA atmospheric correctors; to estimate the effects on positioning by applying the correctors to GPS data processing; and to provide options for ingesting these correctors in the NDGPS modernization program.This paper presents the results of a study conducted to evaluate several different ionosphere error mitigation models and methods. It describes how satellite coverage, as a function of ionosphere corrector availability, plays a significant role in position accuracy.

In December of 2004, the University of Southern Mississippi (USM) deployed an ocean observing data buoy in the northern Gulf of Mexico. To facilitate the measurement of long-period vertical movement, such as tides, dual-frequency GPS receivers were installed on the buoy and at three shore stations. The shore stations were located at ranges of 20 km, 56 km and 100 km. The 20 km baseline was established to determine the true buoy position; the other two baselines were established to facilitate investigations into the mitigation of atmospheric effects (both from the ionosphere and the neutral atmosphere) on long-baseline, high-accuracy vertical positioning with ambiguity resolution.On August 29 of 2005, Hurricane Katrina came ashore along the northern Gulf of Mexico. The USM buoy survived the storm and continued to collect data until it was recovered, approximately 13 km from its original mooring. Of the three base stations, two collected data until they lost power due to storm effects, and the third (56 km baseline) was completely destroyed and all storm data was lost. The dry conditions (low tropospheric wet delay) of the week prior to the storm provided optimum GPS positioning conditions, which was in stark contrast to the high atmosphere moisture content (high tropospheric wet delay) leading up to and during the storm.Previous studies by the authors have focused on evaluating the individual utility of new tropospheric models (e. g., NOAA) or new ionospheric models (e. g., NOAA MAGIC and NOAA USTEC) to improve float ambiguity, static baseline positioning. In the current study, improved tropospheric and ionospheric models are used in combination to improve baseline processing. Kinematic buoy data are processed from the week of August 23 through 30, 2005, and long-baseline integer ambiguity resolution (AR) is attempted. An important question to answer is " Can decimeter-level AR positioning be achieved with the aid of improved atmospheric modeling? To further place these results into the context of contemporary positioning accuracy, processing solution comparisons are made between in-house software ingesting the external atmospheric models and COTS processing software, for short and long baselines, under static and dynamic conditions.

Distance education is big business in some fields such as business and computer education but it has proved very difficult to provide satisfactory distance education in the mathematical sciences. This paper describes an attempt to carry out tutoring in the subject area of mechanics in small groups and at a distance, i.e. the tutors and the students communicate via an Internet based e-meeting system rather being present in the same physical room. This is used at a KTH (Sweden) mechanics distance course based on a learning content management system supported with tutoring from AUT (New Zealand) and the reverse tutoring of students at a regular mechanics course at AUT tutored from KTH.

We describe a co-operative project between Auckland University of Technology (AUT) in New Zealand and the Royal Institute of Technology Stockholm (KTH) to provide long range tutoring via the Internet in the subject of Mechanics. Many students enrolled in distance courses which are predominantly technical in nature, have learning difficulties which can be overcome with more personalized tuition.

The U.S. Coast Guard has begun the modernization of its Nationwide Differential GPS (NDGPS) beacon network. One potential component of modernization is to provide the information necessary for long baseline, centimetrelevel, differential carrier phase processing. In order to achieve these results, improved handling of atmospheric refraction of the incoming GPS signals must be achieved. The utility of the NOAA tropospheric delays in position determination was accomplished by supplying the NOAA zenith delay estimates to an in-house ionospheric-free relative GPS processor. Results indicate that the most significant improvement is observed in upcomponent bias reduction of a few centimeters to more than four decimeters.

In this paper we use the term Post-Processing Kinematic (PPK) to refer to the process of deriving 3D ambiguity-resolved carrier phase differential GPS positioning results without the use of a real-time data link. PPK is crucial for vertical positioning in hydrographic surveying. Positioning system performance often involves a tradeoff between positioning uncertainty and effective coverage (range). PPK is at the uncertainty end of this tradeoff, with restricted coverage due in significant part to problems in modeling differential tropospheric delay, particularly the wet component. Tropospheric delay is of concern for marine vertical positioning for three reasons: (1) Tropospheric uncertainties map primarily into vertical position uncertainties. (2) Tropospheric conditions are less densely sampled at sea than over land. (3) Tropospheric uncertainties contaminate the cycle ambiguity resolution process, making extended-range marine PPK positioning difficult to achieve. This paper describes initial results from a three-pronged campaign to overcome this limitation: (1) Collection of a marine PPK database, under varying tropospheric conditions with seasonal variations in different climates. Initially data are being collected from the Princess of Acadia ferry repeating the same route 4 times daily across the Bay of Fundy (the Lagrangian approach), and from a stationary moored buoy in the Gulf of Mexico (the Eulerian approach). (2) Development of better tropospheric models, based on analysis of precipitable water vapour associated with the PPK database, determined from (a) GPS measurements, (b) local weather measurements, and (c) regional weather models. The tool we use to assess the success of a PPK tropospheric model is the comparison between short baseline (less than 10 km) PPK solutions (for which PPK is reliable and uncontaminated by differential tropospheric uncertainties), and simultaneous position solutions from longer PPK baselines over which the tropospheric models are being assessed. (3) Implementation of these models into better algorithms for four independent software packages, each capable of PPK processing, developed by Ben Remondi and Kendall Ferguson of XYZs of GPS Inc.; by Don Kim at UNB; by Sunil Bisnath at UNB and USM; and by Dave Dodd at UNB and USM.

Abstract In this paper we use the term Post-Processing Kinematic (PPK) to refer to the process of deriving 3D ambiguity-resolved carrier phase differential GPS positioning results without the use of a real-time data link. PPK is crucial for vertical positioning in hydrographic surveying. Positioning system performance,often involves a tradeoff between,positioning uncertainty and effective coverage (range). PPK is at the uncertaintyend of this tradeoff, with restricted coverage due in significant part to problems in modeling differential tropospheric delay, particularly the wet component. Tropospheric delay is of concern for marine vertical positioning for three reasons: (1) Tropospheric uncertainties map,primarily into vertical position uncertainties. (2) Tropospheric conditions are less densely sampled,at sea than over land. (3) Tropospheric uncertainties contaminate the cycle ambiguity resolution process, making extended-rangemarine,PPK positioning difficult to achieve. This paper describes initial results from a three-pronged,campaign,to overcome this limitation: (1) Collection of a marine PPK database, under varying tropospheric conditions with seasonal

Traditionally, engineering design has been considered to be the core of engineering education. This has been reiterated more recently with the joining of design curriculum to the initial formation of graduate capabilities by making explicit what has often been implicit in design papers all along - teamwork, problem solving, time constraints, interpretation of client and engineering constraints, aesthetics of design etc. More recently, alternative engineering curriculum have been developed responding to both interdisciplinary developments in engineering and redefinition of engineering roles away from traditional discipline specialisation. The core requirement of design remains both from the perspective of validation of 'new' or 'hybrid' engineering degrees and the ability to bring 'real-world' scenarios inside the classroom. This paper outlines how this challenge to remain 'true' to engineering's traditional focus of design education particularly for mechanical engineers, while working with an over-full 'hybrid' curriculum, is being resolved in the Bachelor of Engineering programme at Auckland University of Technology. Feedback and advice are sought in order to help deliver significant student learning experience.