Week of October 31 - November 4
The field work to support initial results in GSVS11 finished this week. Much of the processed data was almost immediately available by end of the week. NGS intends to make the complete data sets of this survey available online by early 2012.
Leveling: Leveling was completed on November 1. Crews packed up and headed home on November 2. An initial set of differential Helmert orthometric heights, based on the new leveling but the old NAVD 88 gravity file was computed and turned in by November 4. The leveling processing team will use the newly collected gravity data for even more updated values of differential Helmert orthometric heights next week.
GPS: All GPS receiver files on the 218 official marks were processed through the OPUS-S gateway program to OPUS-Projects, and turned in. A network adjustment is planned for next week.
RTN: The RTN survey was finished, but for 4 final points near Rockport, over the weekend of November 5 and 6.
Gravity/Gradients: The relative gravity survey concluded on November 2. NGS personnel traveled to NGA St. Louis to gain assistance in the processing of the relative gravity network. Final values were turned in on November 6.
Imagery: A complete set of geo-rectified imagery files was turned in on November 3rd, in GeoTIFF, ECW and KML formats. A few interesting tidbits should be mentioned. First, in case there was any doubt about the multi-week 100+ degree temperatures and severe draught that took place during the GSVS11 survey, one might compare this original Google Earth image with the image taken during GSVS11.
Also, a close inspection of Longhorn Stadium shows that NGS captured a clever message in our imagery. See if you can spot it. It was spelled out using the "flippable seats" in the stadium. Despite NGS inquiries, the author remains anonymous.
LIDAR: GeoTIFFs of ellipsoid height DEMs were turned in on November 3rd. Work was begun on creating a parallel product of ASCII DEMs. Full coverage of the LIDAR DEMs can be seen here.
Week of October 24-28
Leveling: Leveling was nearly completed this week. Some additional misclosures now put the final day of leveling at November 1. Final deliverable of differential orthometric heights is still expected to be done November 11.
GPS: Processing of the static GPS in OPUS-Projects continued this week. Final deliverable of differential ellipsoid heights is expected to be done November 11.
RTN: The RTN survey continued this week, with delivery of coordinates on all camera points to be done by November 4.
DoVs: When the delivery of RTN coordinates occurs, processing of the DoV data can be concluded. Delivery of DoVs is expected on November 11.
Gravity/Gradients: The relative gravity survey continued this week. Full delivery of the final set of gravity values on all points is expected on November 4.
Week of October 17-21
Leveling: Leveling continued with 2 crews in the Sinton area. Current estimates put the last day of leveling, at the Rockport tide gage around October 31. This slight delay is due to a failure to close some sections that had been run one-way in previous weeks in the Corpus Christi area. Final deliverable of differential orthometric heights is expected to be done November 11.
GPS: Processing of the static GPS in OPUS-Projects was done this week. Final deliverable of differential ellipsoid heights is expected to be done November 11.
RTN: The RTN survey continued this week, with delivery of coordinates on all camera points to be done by November 4.
DoVs: When the delivery of RTN coordinates occurs, processing of the DoV data can be concluded. Delivery of DoVs is expected on November 11.
Gravity/Gradients: The relative gravity survey continued this week. Full delivery of the final set of gravity values on all points is expected on November 4.
Week of October 10-14
Leveling: Leveling continued with 2 crews working south of Skidmore. Current estimates put the last day of leveling, at the Rockport tide gage around October 29.
GPS: Significant office work was performed on the data, including the correction of RINEX header information, file naming, etc.
RTN: The full RTN survey began in earnest at the Rockport tide gage. Some technical difficulties downloading the data were experienced, but they were rectified and progress made to Sinton. The survey is expected to take until late October.
Gravity/Gradients: Relative gravity survey instructions were sent, and two operators, using two relative meters each, began the process of doing a relative gravity survey from Austin to Rockport.
Week of October 3-7:
Leveling: A 2nd leveling crew arrived, and work continued with the goal of finishing by end of October.
Gravity/Gradients: Instructions were developed this week to perform a relative gravity survey that is anchored at Austin and Rockport A-10 stations.Week of September 26-30:
Leveling: Leveling was reduced down to 1 crew, as crews 2 and 3 went home for the end of the fiscal year. Beginning next week a 2nd crew will be in place and are intended to work with the crew that is still in place, trying to finish this leveling job before the end of October.
GPS: GPS re-observations were completed this week on various points that had bad or missing data.
RTN: New equipment necessary to perform the RTN was tested. Starting next week, the RTN survey should be started up again and run about two weeks into October.
Gravity/Gradients: Both the FG-5 and A-10 were returned to Micro-G/Lacoste for repair. A gravity crew of two remained in Texas with 5 working relative gravimeters. Gradient work was put on hold. Because gravity is required for processing the leveling data, the plan to use the A 10 on all 218 marks was put on hold until at least January and a new plan to perform a relative gravity survey, tied to the existing A-10 absolute gravity marks in Austin and Corpus Christi, was developed. It is expected to be complete before the end of October.
DoVs: Processing of the DoVs is on hold, being dependent upon completion of the GPS processing on both the 218 official marks as well as the eccentric camera marks. The eccentric marks are mostly done (having been surveyed and processed with OPUS-RS), but the re-obs of the official marks has delayed the final processing of the 218 official marks.
Week of September 19-23:
Leveling: Leveling continued with 3 crews. The crew members for the October leg of leveling have been identified, and there will be two full 4-person crews running that month in an attempt to finish.
GPS: GPS re-observations on bad/missing points took place this week up and down the entire line.
Gravity/Gradients: FG-5 measurements took place at Austin and Corpus Christ this week, just in time for the FG-5 to break down. With similar luck, the A-10 also broke down this week. Absolute gravity operations were suspended pending repairs. Meanwhile, a new plan to replace the absolute A-10 values with relative gravity measurements, anchored at Austin and Corpus Christi, was designed. This will be the only viable way to have gravity at all marks before the end of October.
DoVs: Our Swiss guests packed up the camera and themselves and got everything back to Switzerland. It was a successful venture, and now begins the long processing. Final values will not be available until all GPS data is processed, which will not occur until the re-observation campaign is complete.
Week of September 12-16:
Leveling: Leveling continued south of Kenedy, toward Karnes City. While a 3rd leveling crew was preparing to travel to Texas to accelerate leveling work, it was finally obvious that leveling will not be complete by the end of September. Plans to have the 3rd crew move down will remain in place, but they will return at the end of September, with 2 crews remaining in place to finish leveling work, likely by the end of October.
GPS: Some bad news arrived from the GPS crew chiefs. Significant portions of the static GPS survey data appear to be lost, or to have degraded solutions (bad RINEX, severe multi-path, etc). To correct this situation, a re-observation schedule, utilizing 5 GPS units over two weeks has been set up and will begin early next week.
RTN: OPUS-RS occupations continued and were completed this week. (And there was much rejoicing!) On another positive note, it seems that our own RTK equipment might be modified so as to access the TXDOT RTN and the actual RTN portion of the survey could be re-instituted. Solutions for this were being worked on through the week and into the weekend.
Gravity/Gradients: The gradient team worked in Austin until around September 15th, but then had to leave for other NGS work. Thankfully A-10 work began again with the return of both instrument and operator. Unfortunately they seemed to have brought torrential rains with them and this required some creative, but successful, use of waterproof tents over the A-10 during observations.
DoVs: An additional night of observations, as a densification survey around Aransas Pass was performed, at the request of the NRC.s TRB. The camera crew then began moving north, performing re-observations around every 20th point, just as an accuracy check of previous observations.
Week of September 5-9:
Monday the 5th was labor day, and all crews took a well deserved day off.
Leveling: Leveling continued south of the Kenedy area. Thankfully the heatwave has abated, but that only means the 100+ degree temperatures have dropped into the 90.s.
GPS: Office work continued, with most of the GPS files being organized, renamed and put into OPUS-Projects for eventual processing as a single adjustment. Unfortunately as this work continued, it began to appear that some files had been lost during the six weeks in the field. Searches for these files continued.
RTN: The OPUS-RS replacement survey for the RTN-on-PK nails continued with an efficient collection of almost 20 points per night. Work was primary done around Corpus Christi, and then the crew went to Austin to begin moving down the line (skipping the already-RTN.d portion in the construction zone). While this doesn.t solve the overall loss of the RTN portion of the survey, it does make it likely that the primary mission of the RTN portion (GPS positions on all Camera marks by end of September) will occur.
Gravity/Gradients: The A-10 was still absent on other assignment, and the FG-5 idle still (with no available personnel to run it). Regular collection of gradients continued along the line in the Austin area.
DoVs: The camera crew reached Rockport and completed observations on the final (218th) point of the survey on the night of Saturday, September 10th. And there was much rejoicing.
Week of August 29- September 2:
Leveling: Additional leveling personnel arrived this week. Although originally set up as a 3rd leveling crew, they were instead enveloped into the first two crews due to attrition for various reasons (medical, personal, etc).
GPS: The static GPS observations were completed last week, and this week was dedicated to office work, including the finding and naming of files, and processing of GPS data. Also, although the LIDAR portion of the survey has long since been over, only this week did the TXDOT return their CORS stations from the 1 second data rate to 5 seconds.
RTN: The RTN portion of the project was given a significant set-back this week, as the equipment loaned to our RTN crew was requested back. This came without warning, and so the entire RTN portion of the survey was put on hold. To replace one part of the RTN survey (the need for good GPS positions on the DIADEM camera marks), a short-session (20 minute) GPS static survey, using one GPS unit and OPUS-RS, was put in place. While this serves as a stop-gap measure, it fails to fulfill the original survey instructions of the entire RTN survey.
Gravity/Gradients: The A-10 was absent, and the FG-5 idle still. Final tests of the gravimeters and platform structure (or .G-Pod. as it has come to be affectionately called) were complete, and collection of gradient data finally commenced on Friday the 2nd at the Austin end of the line.
DoVs: The ATV broke down early this week, necessitating one night of manually moving the camera over each mark. It was fixed and regular observations were underway the next night. Observations continued at about 10 points per night, and by Saturday the 3rd, only 50 points remained of the 218 total to observe in the entire survey. The wildfires near Austin caused smoke cover to interfere with observations one of the nights.
On a separate note, a special request from the National Research Council.s Transportation Research Board came in to NGS, regarding this survey. Discussions between the TRB and NGS resulted in an agreement by NGS to add a DoV densification survey (one extra night of observations) during GSVS11, around the Aransas Pass area, in order to facilitate some research being done by the TRB.
Week of August 22-26:
Leveling: Two crews continued leveling, and reached just south of Belmont by the end of the week. Plans for adding a 3rd crew next week, and a 4th by early September were put in place, in order to minimize the amount of work necessary to carry over into the next fiscal year.
GPS: The efficient collection efforts of the GPS crew continued to work so well that the final observations were performed on Saturday, August 27th on the last point of the survey (PID AN1877; Designation 877 4770 TIDAL 8). Data wrangling and processing were ramped up.
RTN: The RTN component of the survey began on August 23rd, with the surveying of 18 Camera marks (PK nails) in the construction zone south of Austin. These points were chosen out of fear that they would be destroyed during construction. Sure enough, 2 of the points were already destroyed when the RTN crew arrived. Plans to re-set and re-observe these with both the DIADEM and GPS were made for the end of the survey.
Gravity/Gradients: The A-10 continued to be absent (in Yellowstone for other pre-scheduled work), and the FG-5 was idle, due to some unanticipated personnel shuffling. The gradient crew worked on testing the L/R relative gravimeters and also on the multi-level platform structure that will be used for vertical gradients.
DoVs: Camera work continued, averaging about 10 points per night. New crew members began rotating in this week as well. By the end of the week, 50% (109 marks) of the 218 official marks had been observed.
Week of August 15-19:
Leveling: While the heat showed no signs of abating, the leveling crews are continuing to work early morning hours until mid day, in order to keep out of the worst of it. On Wednesday, both crews moved to San Antonio, in order to reduce drive time while working on the middle of the line. Estimates of the completion date, based on work done so far, show a likelihood that this part of the project will go over the September 30th deadline.
GPS: The GPS crew was making enough speed down the line that they moved to Corpus Christi on Sunday the 14th. Work was concentrated around Kenedy and points south.
Gravity/Gradients: The FG-5 was moved to Bowie High School (where a superconducting gravimetry experiment is being run by the UT Austin) for observations on mark "AUSTIN A C " overnight of the 15th and 16th. A check on the machine on the 16th showed that a mis-setting required another day of observations. It was moved on the 17th. Gradient work began in Austin this week as well.
DoVs: The DIADEM camera and NGS's visiting scientists arrived safely in Austin on Friday the 12th. Modifications were made to the camera's trailer over the weekend, and some tests were performed to confirm that the camera could be operated over the hard packed earth of Texas as well as on asphalt. They were successful, and operational observations began on Monday night, averaging about 10 points per night. Also, a wind screen was built to minimize the impact of the excessive winds on the camera. When a point was not easily accessible by the trailer, an eccentric point was establishedThese points will be connected later to the official points through an RTN survey, As of Thursday, 32 points had been observed.
LIDAR/Imagery: LIDAR and imagery flights were concluded on Monday the 15th. Processing of the data will now commence, with a high resolution DEM as the initial goal.
Week of August 8-12:
Mark Setting/Recon: Reconnaissance and Mark Setting was complete as of August 5.
Leveling: The heat wave continued unabated, but the leveling crews persevered. On Thursday the Trimble level experienced some malfunction, so replacement equipment was shipped from Corbin while the faulty level was sent for repair.
GPS: On Monday, fourteen of the 20 GPS receivers were established over 7 "good" and 7 "bad" bench marks to support an experiment that will use this data and that from the Austin LIDAR flights. Work on the regular 20-reciever setups down the official line resumed on Wednesday.
Gravity/Gradients: The FG-5 began its observations at the Pickle Research Campus, one of the four building-interior marks for this survey. The A-10 continued working down the line until Wednesday, when both the A-10 and its operator left the survey to fulfill a pre-existing commitment elsewhere. The A-10 work will resume in mid-September.
DoVs: Reconnaissance of the official marks, for their suitability of use by the ATV/Trailer system that will haul the DIADEM camera, began. Also, two scientists from Switzerland, Beat Bürki and Sébastien Guillaume, who will operate the DIADEM are scheduled to arrive the night of August 11th. The DIADEM camera itself was confirmed as having arrived in Houston, and expected to clear customs to arrive in Austin between August 11 and August 15.
LIDAR/Imagery: Low level cloud cover kept us from flying over the weekend, but LIDAR flights finally began in Austin on Monday. By Friday, all by the final area around Rockport had been flown. And although it's not as impressive as "the horseshoe" at Ohio State, we did manage to catch Longhorn Stadium from the air using LIDAR.
Week of August 1-5:
Mark Setting/Recon: All mark setting was finished this week, including the entire line of official points, and the repair of some existing points. The KML file of the "official" points (which will have, at a minimum, leveling, GPS, absolute gravity and vertical gravity gradients) is here. Many of these marks are also accessible for the DIADEM camera, but a survey procedure is in place if offset marks for the camera need to be used.
Leveling: The weather has been atrocious, with the crews suffering 100+ degree days regularly. The aBFFB procedure was abandoned as of Monday afternoon, in favor of standard BF. This decision was made primarily on the excessive heat and the time lost from the extra data collection. NGS will re-visit aBFFB in the near future, on a shorter line in nicer weather was agreed to.
GPS: The static GPS campaign has been cranking along at a fast rate, running 20 receivers simultaneously and leapfrogging 10 of them forward daily. Current best estimate is to complete the survey before the 2nd week of September, fully 3 weeks early. The crews broke out of standard setup mode to support a special experimental setup for use during the LIDAR survey while the LIDAR is being flown around Austin. Seven "good" and seven "bad" benchmarks were identified, and GPS was collected at 1 second rate on these 14 marks during the LIDAR survey. These data will be part of an NGS study on the use of GPS and bench marks and LIDAR in creating digital elevation models in NAVD 88 orthometric heights.
Gravity/Gradients: A-10 work continued south of Austin on the official line. The FG-5 and relative meters were being driven to TMGO, but the truck broke down just outside of Austin.. Repairs are underway, and FG-5 work is expected to begin next week.
DoVs: The DIADEM camera was shipped on Tuesday the 2nd and is expected to arrive on Thursday the 8th. The ATV/trailer system for the camera was loaded into the truck and the whole rig began its journey from Corbin to Austin on August 6th..
LIDAR/Imagery: The plane arrived in Austin on Friday the 5th. LIDAR was planned to begin over the weekend of August 6/7. Imagery may have to be cut back due to the perpetuation of daytime clouds. Identification of 10 good and 10 bad bench marks was not entirely successful, but 7 good and 7 bad were found and suitable for GPS. The TXDOT was given notification of the flights and are expected, due to previous agreement, to ramp up their CORS data rates to 1 second during this time. The two NGS temporary CORS in Luling and Nixon were also ramped up to 1 second.
Week of July 25-29:
Mark Setting/Recon: Crew reduced to 2 (with one on vacation), but work continued toward the Rockport finish line; may have to return to one spot on the line to install an additional mark at an overly-long gap and also to repair the A-10 collars on a few existing marks. A final list of the various types of points (primary or "official" points, NAVD 88 tie-ins, special building-exterior gravity points, etc) is almost complete and disseminated in KML, so all crews know exactly what points they are surveying, at least for the first 80% of the line.
Leveling: Leveling continued in the area of Lockhart. The aBFFB procedure has been used since last week and is causing significant slow downs. The data is being analyzed to determine if aBFFB is removing systematic error build up. A decision on this is expected by middle of next week.
GPS: The static GPS campaign began in earnest in Austin. At last count, NGS will be leapfrogging 20 receivers at a time. Two temporary CORS locations were identified and set up and are running in Luling and Nixon. We had a little excitement as the Texas Highway Patrol brought bomb-sniffing dogs to investigate our (unattended) equipment near the State House. Lesson learned.
Gravity/Gradients: A-10 work began in Austin on the official line. The FG-5 and relative meters are still being worked on at TMGO.
DoVs: Travel plans for our visiting scientists were finalized. The DIADEM camera is being shipped early next week for an arrival a few days later.
LIDAR/Imagery: Still currently scheduled for about 4 days of flying sometime between August 1 and August 15. There is a small chance this will be impacted by an overly energetic hurricane season (causing the plane to be committed elsewhere), but for now all is a "go" still for the flights. Still working to identify the 20 bench marks (10 good, 10 bad) which will be occupied with GPS during these days.
Week of July 18-22:
Mark Setting/Recon: Nearly all official marks are set, with just a handful remaining in the Corpus Christi area, plus the four building-interior absolute gravity marks need to be set (3 in Austin, 1 in Rockport)
Leveling: Both crews arrived this week in Austin and while one is doing a 3 mark tie to existing NAVD 88 marks near Austin, while the other began by supporting the GPS crews at the test grid.
GPS: Crews arrived this week in Austin and began collecting up and testing equipment in a grid (an "antennae farm"). Bad weather disrupted the tests on Tuesday, but work progressed afterward. Full scale GPS production begins in earnest next week.
Gravity/Gradients: Equipment is being prepared for shipment to Texas.
DoVs: Crews were identified and will begin arriving with equipment between August 5 and 12 with work beginning on August 15.
LIDAR/Imagery: Currently scheduled for about 4 days of flying sometime between August 1 and August 15.
