Use of OPUS-DB to supplement coverage shows great promise as a means of readily collecting information without the need for following the Bluebook, but doing so where it can provide the most improvement to future geoid height models for datum transformations. National Geodetic Survey. The intent is to capture the mid-wavelengths of the gravity field over all of the U. GRAV-D bridges the gap between long wavelengths determined by satellite gravity missions and shorter wavelengths determined from surface observations as well as forward-modelling of surface density and elevation models.
The GRAV-D surveys were collected in km spaced profiles covering km patches, which are adequate in scale to compare to Earth Gravity Models through about degree Initial comparisons with EGM revealed no detectable slope across these patches, supporting the idea that no significant long wavelength differences exist between the aerogravity and the GRACE satellite data on which EGM is based.
With the release of the GOCE data, higher resolution EGM's based entirely upon satellite gravity models make this comparison a more direct assessment of the long to intermediate quality of the aerogravity. This will enable generation of an EGM with 20 km resolution approximately degree In turn, this model will be combined with the existing terrestrial data to build a higher resolution model towards defining a cm-level accurate gravimetric geoid model to be used as a new vertical datum for the United States.
For NAVD 88, Helmert orthometric heights were defined in a block adjustment of over , geopotential differences at bench marks. This provides the ease of calculating your position with GPS but yields more practical orthometric heights. Because of the requirement for both heights on a bench mark, the pool of control points is much smaller only about 18, and not very equitably distributed with potential dm-level interpolation errors.
This nascent database is rapidly being accepted by the broader surveying community and can even be used to target significantly deficient areas. These points fell into three categories: 1 80 that were common to both databases and were used in making GEOID09, 2 57 that were common to both but not used in making GEOID09, and 3 with new geometric observations for points not previously observed with GPS i.
Smaller values imply a better fit and less noise. Overall, OPUS-DB demonstrated very good agreement with more rigorously determined NGSIDB data, provided expanded coverage into regions with poor coverage, and demonstrated a significant potential for use in future geoid modeling. A recommended method to accomplish that is to reference the project to the well-known and respected reference system, the National Spatial Reference System NSRS.
It will also update the audience about NGS' goals for improving the definition and delivery of horizontal and vertical datums. This session will inform the audience about new methods developed by NGS to facilitate easy access to data for approximately 1. OPUS utilities, which can be used to establish, or check, coordinates and elevations for projects referenced to the NSRS, enabling users to complete their work more efficiently.
Also to be covered will be information about resources that are available to anyone needing assistance with locating, using, or producing geodetic information about their projects. Attendees will learn about NGS' Geodetic Advisors, who are located around the United States with the purpose of educating and assisting people in utilizing NGS products and services in their projects or applications. Nearly every effort that involves planning, protecting, or monitoring our Nation's coasts and Great Lakes relies on knowing or establishing geographic positions and elevations of objects or locations-of-interest in the project area.
This session will discuss the relationship of geodetic and tidal vertical datums, and the necessity of understanding how to describe the relationship. The input data can be elevations or bathymetric soundings, and batch files can be submitted. A brief tutorial will illustrate how to use the software, the accuracy associated with the conversions, and some of the common errors that users make.
This session will provide information about the efforts underway to produce a new International Great Lakes Datum IGLD , with a goal for release in Being discussed are the reasons why a new IGLD is desirable, the data collection and analysis effort to update the datum, and examples of the impact of the new datum on the Great Lakes region.
Global Navigation Satellite System GNSS data processing requires many different numerical models to describe the physical processes affecting the positions of the satellites and points on the ground as well as the propagation of the GNSS signals from the satellites to the user.
Some of these models are commonly known: satellite orbits, tropo and antenna corrections are examples from this group. Others are probably less well known: phase wrapping, atmospheric gradients and solid Earth tides are examples from this group. In this presentation, many of these models will be described with a focus on broader conceptual understandings rather than detailed technical descriptions.
Real examples from data processing will be included whenever possible thereby adding the magnitudes of these physical processes to your understanding. The ultimate goal is to give you a better awareness of what your GNSS processing software should be doing to give you the accuracy necessary for your needs. Although its mission has adapted to changing times and technology, this two hundred year history is alive in the NGS today.
Using an overview of the NGS as an organizing framework, some NGS activities of particular interest to the surveying communities will be highlighted. Among the activities highlighted in this presentation are: improved coordinates for the CORS and a large subset of the passive mark networks NAD 83 and NA ; the related work to define a new hybrid geoid model providing improved consistency with these new coordinates and velocities GEOID12 ; the Gravity for the Redefinition of the American Vertical Datum GRAV-D mission to create a snapshot of gravity across the United States in unparalleled detail; the Online Positioning User Service OPUS providing virtually hands-off, high-accuracy GNSS data processing; and the creation of guidelines to help real-time network providers more rigorously tie their networks to the global and national datums.
Several notable enhancements have been implemented or are pending for OPUS. OPUS-Projects includes project visualization and management tools, enhanced processing options, and one click publishing for an entire project. OPUS is testing a new static processing strategy.
The purpose of this project is to replace the current official vertical datum, NAVD 88 the North American Vertical Datum of with a geopotential reference system based on a new survey of the gravity field and a gravimetric geoid. These will be surveys designed to independently measure the geoid to provide a check against both the data and theory used to create the final gravimetric geoid which will be used in the geopotential reference system.
The survey took place over a kilometer line running more or less north-south from Austin to Corpus Christi, Texas. This region was chosen for many factors including the availability of GRAV-D airborne gravity over the area, its relatively low elevation meter orthometric height max , its geoid slope about cm over km , lack of significant topographic relief, lack of large forestation, availability of good roads, clarity of weather and lack of large water crossings.
This talk will outline the initial results of the survey, specifically the comparison of various geoid slopes over this region: gravimetric geoid models with and without airborne gravity , minimally constrained GPS and leveling and from astro-geodetic deflections of the vertical. These load corrections have been applied to the most current station time series from the International GNSS Service IGS for a global set of stations, each having more than weekly observations. The stacking of the weekly IGS frame solutions has taken utmost care to minimize aliasing of local load signals into the frame parameters to ensure the most reliable time series of individual station motions.
For the first time, dN and dE horizontal components have been considered together with the height dU variations. By examining the distributions of annual amplitudes versus WRMS scatters for all stations and all three local components, we find an empirical error floor of about 0.
Only the very best performing GPS stations approach these floors. Most stations have larger scatters due to other non-load errors. These global error floors have been verified by studying differences for a subset of station pairs located within 25 km of each other. Of these, 19 pairs share a common antenna, which permits an estimate of the fundamental electronic noise in the GPS estimates: 0.
The remaining close pairs that do not share an antenna include this noise component as well as errors due to multipath, equipment differences, data modeling, etc, but not due to loading or direct orbit effects since those are removed by the differencing.
A similar comparison for periodic signals implies that about a third of the GPS draconitic harmonics probably arise from sources local to the stations whereas the remaining two-thirds comes from orbital effects. Ray et al.
King and Watson [] have studied the propagation of local multipath errors into draconitic position variations, but orbit-related processes have been less well examined. Finer structures within the sub-seasonal bands fall close to the expected alias frequencies of subdaily EOP tide lines but do not coincide precisely. While once-per-rev empirical orbit parameters should strongly absorb any subdaily EOP tide errors due to near-resonance of their respective periods, the observed differences require explanation.
This has been done by simulating known EOP tidal errors and checking their impact on a long series of daily GPS orbits. Indeed, simulated tidal aliases are found to be very similar to the observed orbital features in the sub-seasonal bands.
Moreover and unexpectedly, some low draconitic harmonics were also stimulated, potentially a source for the widespread errors in most IGS products. How do we achieve confidence with our Real Time RT work? What pitfalls should we avoid? Are there guidelines to follow to help us with our procedures? How accurate are the Real Time Networks? Should I be using Glonass? Those are just some of the common questions surveyors, engineers and other geospatial professionals ask when they go to the field to obtain RT GNSS positional coordinates.
Because so much of RT GNSS positioning is transparent to the user and is entirely dependent on the field technician to bring back good data, it is incumbent on that technician to follow correct procedures and certain criteria to ensure a successful campaign.
Each is composed of 24 hr of observed orbits, with an initial latency of 3 hr, together with propagated orbits for the next 24 hr. We have studied how the orbit prediction performance varies as a function of the arc length of the fitted observed orbits and the parameterization strategy used to estimate empirical solar radiation pressure SRP effects.
To focus on the dynamical aspects of the problem, nearly ideal conditions have been adopted by using IGS Rapid orbits as observations and known Earth orientation parameters EOPs. Performance was gauged by comparison with Rapid orbits as truth by examining WRMS and median orbit differences over the first 6 hr and the full 24 hr prediction intervals, as well as the stability of the Helmert alignment parameters. Note that the actual IGS Ultra-rapid accuracy is limited mostly by rotational instabilities, especially about the Z axis due to errors in near real-time and predicted UT1 values.
We found that observed arc lengths of 40 to 44 hr produce the most stable and accurate predictions during Adjusting all 9 SRPs offsets plus once-per-rev sines and cosines in each D,Y,B component for each satellite shows smaller mean subdaily, scale, and origin translation differences.
On the other hand, when the 4 once-per-rev SRPs in the D and Y directions are held fixed, then smaller, more stable rotational differences are obtained. Actual Ultra-rapid performance will be degraded due to larger errors in the available near real-time observed orbits and EOP predictions.
Geodetic GNSS applications routinely demand millimeter precision and extremely high levels of accuracy. To achieve these accuracies, measurement and instrument biases at the centimeter to millimeter level must be understood.
One of these biases is the antenna phase center, the apparent point of signal reception for a GNSS antenna. It has been well established that phase center patterns differ between antenna models and manufacturers; additional research suggests that the addition of a radome or the choice of antenna mount can significantly alter those a priori phase center patterns.
For the more demanding GNSS positioning applications and especially in cases of mixed-antenna networks, it is all the more important to know antenna phase center variations as a function of both elevation and azimuth in the antenna reference frame and incorporate these models into analysis software.
The NGS facility was built to serve traditional NGS constituents such as the surveying and geodesy communities, however calibration services are open and available to all GNSS users as the calibration schedule permits. We describe the NGS calibration facility, and discuss the observation models and strategy currently used to generate NGS absolute calibrations. We demonstrate that NGS absolute phase center variation PCV patterns are consistent with published values determined by other absolute antenna calibration facilities, and compare absolute calibrations to the traditional NGS relative calibrations.
Although originally designed to enable accurate positioning and time transfer, the Global Positioning System GPS has also proved useful for remote sensing applications. These two signals interfere, and the composite signal recorded by the GPS receiver can be post-processed to yield the distance between the antenna and the reflecting surface, that is, distance to the snow surface. We present the results of a new snow depth product for the state of Minnesota over the winter of Although single-station examples of GPS snow depth measurements can be found in the literature, this is one of the first studies to compute GPS snow depth over a large regional-scale network.
We chose Minnesota because the state Department of Transportation runs a network of continuously operating reference stations CORS with many desired characteristics: freely available data, good GPS station distribution with good proximity to COOP weather stations, GPS stations located adjacent to farm fields with few sky obstructions, and receiver models known to have sufficient data quality for GPS-IR.
First, because we leverage existing CORS, no new equipment installations are required and data are freely available via the Internet. We present snow depth results for over 30 GPS stations distributed across the state. The changes in these datums will have a significant impact on the users of geodetic data nation wide.
This presentation will describe the existing components of NSRS and the rational for the need to adopt new reference frames. Quantifying Load Model Errors by Comparison to a Global GPS Time Series Solution Various space geodetic studies over the past two decades have shown that temporal variations in the distribution of ocean, atmospheric, and continental water masses cause detectable vertical displacements of the Earth's surface. Unlike most past research that focused on a single load component for only vertical motions, we have included the horizontal, as well as vertical, components and considered atmosphere, non-tidal ocean, surface water load models.
Our geodetic solution is the most current reprocessed station time series from the International GNSS Service IGS for a global set of stations, each having more than weekly observations. The long-term stacking of the weekly frame solutions has taken utmost care to minimize aliasing of local load signals into the frame parameters to ensure reliable time series of individual station motions. Our reference load model consists of components from NCEP atmosphere corrected for high-resolution topographic variations , ECCO non-tidal ocean, and LDAS surface water cubic detrended over to to remove inter-annual artifacts , then combined, linearly detrended, and averaged to the middle of each GPS week as a posteriori corrections.
Alternative load models, for individual components or the total, can be tested against the same set of GPS time series to determine their relative accuracy. The method is sensitive to load model error differences at the level of about 0. We will report relative accuracy differences for a range of load model pairs. It relies solely on ambiguous phase data, and uses a mathematical truth to arrive at absolute TEC values. However the mathematical solution to arrive at UNambiguous TEC from ambiguous phase data remains valid and may prove useful in the future.
This presentation shows the original work that led to VDatum and the pilot projects it supported. Consistency of Crustal Loading Signals Derived from Models and GPS: A Re-examination Various space geodetic studies over the past two decades have detected vertical displacements of the Earth's surface caused by temporal variations in the distribution of ocean, atmospheric, and continental water masses.
Most past research has focused on a single component of the mass load and till now only vertical motions have been examined. Successively stronger correlations have been seen as improvements have been made in the load models as well as in measurements by the Gravity Recovery and Climate Experiment GRACE of surface mass changes and by the Global Positioning System GPS of station height variations.
We have re-examined this problem but included the horizontal, as well as vertical, components and used the most current station time series from the International GNSS Service IGS for a global set of stations, each having more than weekly observations.
The long-term stacking of the weekly frame solutions has taken utmost care to minimize aliasing of local load signals into the frame parameters to ensure the most reliable time series of individual station motions. Fitted annual amplitudes are correspondingly reduced for similar fractions of stations. The weighted mean dU annual amplitude drops from 3.
An absence of dU improvement is nearly only limited to island and coastal sites with small load effects, but degradations for dN and dE are more widespread. Some stations are clearly exceptional due to data problems. The quality and global coverage of current GPS time series has reached a point that they can be used as an independent reference to precisely evaluate the relative performance of competing load models. To achieve the best airborne gravity data accuracy possible, the GPS position solutions must provide not just accurate and precise positions, but accurate and precise velocities and accelerations to be used in calculating gravity corrections.
To our knowledge, no head-to-head comparisons have been done of available kinematic processing techniques with a focus on producing good airborne gravity results. Close comparisons to EGM08 accuracy , the best available global gravity model Pavlis, et al. The flights are described in the data section. The response of the community was outstanding, with some groups submitting multiple solutions: Participating groups: 10; Solutions for each flight: 16; Total solutions for 4 gravity lines : GPS processing types span the range of differential and PPP solutions, with different methods developed by each group.
This presentation provides an overview of why geodesy and datums are important to GIS. Various tools and products are covered so the user is aware of how they can use and access the NSRS and its data. It is a simultaneous least-squares adjustment of nearly 80, passive control stations using a nationwide network of over , GNSS vectors that represent over survey projects spanning from the mid s to August The resulting realization gives positions at an epoch date of January 1, , and it is formally designated as NAD 83 epoch To improve access to the NSRS, NGS developed a new datasheet format that will provide some of the new information associated with NA, such as detailed accuracy information.
NA improves how NGS meets its wide range of customer needs in providing the basis for accurate and reliable georeferencing throughout the US and its territories.
Completion of NA — together with related products and services — represents a significant step toward a more integrated NGS, in terms of both better positions and improved access to the NSRS.
But, how good do you feel about the data you are producing with your real time gear? Are the data collector position quality values displaying precision or are they displaying accuracy and at what confidence level? What position deltas would you expect if you get another shot at a different time or with different weather?
What are the factors that might be affecting your data, anyway? Would it be better to use a new real time network RTN to get your data? Is there any way to have real confidence with a RT established position?
This workshop will discuss how you can have real confidence with real time work and go over the important criteria for the surveyor to achieve successful field campaigns based on the guidelines. Recent and near-future changes in the geodetic datums and other developments being done by NGS are presented by the California Geodetic Advisor. Looking to the far future 10 years , you will learn about the developments that have been initiated to: - totally revamp the horizontal and vertical datums that define the NSRS, - obtain airborne gravity measurements to develop a geoid model accurate to 1 cm, - collect and analyze data for a Gravity Slope Validation Survey.
Topics covered included an overview of selected NOAA geospatial data and services supporting mapping and charting, comprehensive ocean and coastal planning, new approaches for visualizing and using NOAA data, including the latest mobile applications, and the development of a new NOAA Geospatial Platform for access to the breadth of NOAA's geospatial data, services, and applications.
The latter explains that it was because Hinata didn't ask, and he knew he'd see Hinata again after he had noticed 'Karasuno High School' written on Hinata's shirt. When Kageyama asks Hinata about Kenma, Hinata replies that he is Nekoma's setter, which piques Kageyama's interest [6]. Before the match begins, Kenma tells Kuroo that his pre-match speeches are embarrassing, but then trails off as the rest of his teammates take Kuroo's side. The referee whistles to signify the start of the match.
Before he takes his position to serve, Kenma informs Hinata that Nekoma is strong because of the entire team, not just because of him. Kageyama and Hinata perform their signature quick strike right off the bat, which leaves everyone traumatized, including Kenma.
He approaches Hinata and tells him he's shocked, and that their move was amazing. As Karasuno keeps their fast attacks, Nekoma asks for a time-out, where Kenma suggests that all they need to do to stop Hinata is by narrowing his range of movement; they merely keep repeating the same fast move, and all Hinata does is striking where there are no blockers.
So he tells Inuoka to chase him around; even if they can't clear the first round of the game, he will get used to his movement. After repeatedly chasing Hinata, Inuoka manages to touch the ball multiple times, which concerns Kageyama. In this same attack, Hinata attempts to block a fast attack by Nekoma, but surprisingly, Kenma dumps the ball and scores a point for Nekoma. After that, he keeps analyzing the rest of the Karasuno players, and notices that Tsukishima is an intelligent player, unlike Hinata; he observes and thinks carefully before making a move.
Then he fools Tsukishima at the next serve by glancing at his right before tossing to the opposite direction, which proves his theory that Tsukishima is observing him as well. At the benches, Nekomata comments about Kenma's character not being good with people, hence he's constantly concerned about what they think.
Therefore, it makes him good at observing people and coming up with interesting theories about their opponents. Meanwhile, Takeda notes that Kenma doesn't stand out at all compared to Kageyama, but he is capable of incredible things. Ukai replies that it's because of Nekoma's stable receives that Kenma can show his real skills. As the game progresses, Inuoka gets used to Hinata's spikes and manages to block him. However, Hinata starts spiking with his eyes open, and after multiple failures, he clearly sees a pathway through the blockers and aims for it, surprising Kenma and everyone else.
Kenma's phone vibrates, alerting him to a message; Hinata is asking him to do his best at Tokyo prelims. He texts back asking Hinata if he's coming over to Tokyo, and the latter challenges him, saying he's gonna win this time.
The day after that, Hinata shows Tanaka and Nishinoya another text message from Kenma that they already made it through the first round of prelims. When Karasuno team arrives at Tokyo, Kenma sounds confounded at Hinata's absence, but Taketora explains that Kageyama and he are only late for having supplementary exams.
After being yelled at by Coach Nekomata, he explains that his arms are going to break, considering Bokuto's strength. Back at Nekoma's camp, Kenma is sitting and is playing on his video game when Hinata asks him about their middle blocker. Kenma introduces him as the first year Lev Haiba , a half-Russian and half-Japanese blood who was absent at their previous match because he only started volleyball at high school.
He says that it was difficult when they were first paired; their timing was off no matter how hard Kenma tried, but gradually, he started to get used to him. He adds that Lev is so special that he couldn't read him easily, but he is still a powerful asset and an honest but not a bad guy, even though he's too honest at times.
He suddenly stops playing and remarks that Lev's passing basics and serves are worse than Hinata's, which angers Hinata for being a reference for bad playing.
Their conversation makes the rest of the Nekoma players overwhelmed that Kenma is talking to someone without being shy. Next morning, during Nekoma's training match, Lev asks Kenma for an unplanned side hit.
Kenma tosses him the ball, and they manage to score a point. Then Kenma tells Lev that he can't keep asking for a side hit out of nowhere since he can't always keep up. This conversation surprises Hinata and Kageyama, because they had managed to score even though it wasn't planned. Sometime before the qualifiers begin, Kenma confesses to Hinata that he wishes to play a high-stake game against his team that would instantly over once either of their parties lose.
Before the game begins, Yamamoto tries to get Kenma more fired up and vocal but Kenma instead tricks Yamamoto into thinking that Lev 's older sister, Alisa , was watching Yamamoto. The ace believes Kenma and becomes distracted, leaving him to miss a receive and get scolded by the coach.
Halfway into the first set, Kenma notices how Bokuto is excelling in the game with his straight shots. He devises a plan for the Nekoma blockers to cut off the cross shots in order to get Bokuto into the habit of hitting straight shots. Eventually, Kenma is put in charge of getting Lev on track; something Kenma was not fond of but quickly chastises the middle blocker for continuing to make mistakes on things he had been repeatedly told not to do.
However, it does not last long as Akaashi is able to bring Bokuto out of his slump and back into the game to eventually win the match. In Nekoma's match against Nohebi Academy , Kenma is able to pick up that the Nohebi players are baiting Yamamoto and Lev into self-destructing by teasing the two with things they don't want to hear or constantly mess up at certain things.
In addition to these problems, Kuguri poses a threat due to his unreadable form when spiking. As Kenma watches Yaku getting subbed out because of his injury, Nekoma looks to be concerned about how their match is going. At this, Kenma brings them back to high spirits when he says he believes they will be fine. Kenma proves to be a problem to Nohebi when he successfully lands a setter dump and then a surprise back attack with Lev and Kuroo.
Eventually, Nekoma wins the match and makes its way to the Nationals. To find your State Services in your State you can go to www.
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