определение высотной отметки gps приемником

Почитайте, что сказано в инструкции на один из Ваших приборов

 

Владимир, это разница высот точек, полученная РАЗНЫМИ приёмниками.

Оффтоп

Держите свои эмоции при себе

 

Не было никаких "танцев". Просто измерения были приведены к одному знаменателю (интервал 30 сек)

 

Мне это было неинтересно, но думаю, что цифры увеличились (якобы точность уменьшилась).

 

вы хотите сказать что стоите на каждой точке по 4-5 часов. ??? при том что существует проект, калиброван к местной системе координат. увязано 5 пунктов ггс

 

Это почему Вы сделали такие выводы?

 

В.Шуфотинский Модератор сказал:

Очень приблизительно можно посоветовать, чтобы надёжно получить на 7.5км реальную точность в пределах 20мм, надо стоять 4-5часов. Всё остальное: случайности, которые, кстати, могут быть и при многочасовых сессиях. Тут действует во всей красе Закон нормального распределения.

 

Интересно, я для себя что ли выложил кусок инструкции, несколькими сообщениями выше?

 

не могу понять почему многим не нравиться глонас и некоторые его даже отключают при измерениях или потом при обработке с чем связано такое недоверие ????

 

napal,
Они просто не умеют его готовить (с)

 

у меня вопрос стоял еще почему разница в обработке с учетом глонасса. и без?

 

Ну если никто не ответил, то отвечать придется мне.
Разница в количестве спутников
А если серьезно, вот результаты моей обработки расхождения получились в пределах 1 см. Что вполне нормально.
Большая разница в высотах между результатами GB и GR-3 заключается в неправильном измерении высоты антенны, т.к. при изменении метода измерения с вертикально на наклонный, сходимость улучшена.

Нарисуйте как вы измеряли высоту в GR-3.

 

napal, а ещё некоторые зарубежные пользователи очень хотят иметь большую кнопку "Выключить ГЛОНАСС на***н" прямо в диалоге Съемка:))))
видимо, это все влияние стереотипов многолетней давности:)

 

Так, для общего развития: NOAA Technical Memorandum NOS NGS-58

GUIDELINES FOR ESTABLISHING GPS-DERIVED ELLIPSOID HEIGHTS (STANDARDS: 2 CM AND 5 CM) VERSION 4.3 (раскрыть) GUIDELINES FOR ESTABLISHING GPS-DERIVED ELLIPSOID HEIGHTS (STANDARDS: 2 CM AND 5 CM) VERSION 4.3 (свернуть)

Observations:
The following requirements are for both 2-centimeter and 5-centimeter standards, unless otherwise stated.
1. Dual-frequency, full-wavelength GPS receivers are required for base lines greater than 10 km and are the preferred type of GPS receiver for all observations, regardless of base-line distance. Geodetic-quality antennas with ground planes are required. Whenever possible, antennas used during a project should be identical; otherwise corrections must be made for antenna phase patterns. Different makes and models of antennas have different antenna phase patterns. If antenna phase patterns are not accounted for, mixing different antennas in a project can cause vertical discrepancies of as much as 10 cm. Some manufacturers are including software packages which correct for the use of different antennas. (It should be noted that choke ring antennas help reduce the effect of multipath and are highly recommended.)
The manufacturer, model, and complete serial numbers of all receivers and antennas must be included on each station Session Observation Log.
2. The survey shall be referenced to at least three existing National Spatial Reference System A- or B-order three-dimensional control stations near the project area. The survey will also consist of at least three primary base stations that are referenced to the three control stations and interspersed throughout the project. The survey will also include secondary base stations and local network stations to meet the spacing requirements in item 5., below. Primary and secondary base stations can be newly established stations in this project.
A sample project with observing scheme is depicted in figure 1 located at the end of the section. A summary of the guidelines is provided in table 1 located at the end of the vector processing section. See Appendix A for more information about control, base, and local network stations.
3. For control stations and primary base stations, receivers shall collect data continuously and simultaneously for at least three, 5-hour sessions on 3 different days during the project.
4. Observation periods for stations other than control stations and primary base stations are as follows:

1. For the 2-Centimeter Standard: Each base line (adjacent station pair) must be occupied
   for a minimum of 30 minutes per session.
2. For the 5-Centimeter Standard: Observations between primary and secondary base
   stations must be for a minimum of 30 minutes per session. While there is no minimum observation time for local network stations, each base line (adjacent station pair) must be occupied long enough in each session to ensure that all integers are fixed and the RMS for the base line solution does not exceed 1.5 cm.

5. The observing scheme is based on the GPS survey of marks spaced as indicated below for 2- and 5-centimeter standards. Stations in the scheme are noted as either control, primary base station, secondary base station, or local network stations. (The observing scheme chosen for a sample project is depicted in figure 1, page 7.)
For the 2-Centimeter Standard: Spacing between local network stations cannot exceed 10 km; the average spacing must be less than or equal to 7 km. Spacing between primary base stations cannot exceed 40 km and spacing between primary and secondary base stations cannot exceed 15 km. For the 5-Centimeter Standard: Spacing between local network stations cannot exceed 20 km; the average spacing must be less than or equal to 10 km. Spacing between primary base stations cannot exceed 50 km and spacing between primary and secondary base stations cannot exceed 20 km. (Note that secondary base stations may not be required in projects of small areal extent. See Item 2. above.)
6. The observing scheme for all primary base stations requires that each primary base station must be connected to at least its nearest primary base station neighbor and nearest control station according to the observing procedures stated in item 3., above. Primary base stations must be traceable back to two control stations along independent paths.
In addition to this requirement for primary base stations, the observing scheme for all base stations (primary and secondary) requires that each base station be connected with at least its two nearest primary or secondary base station neighbors according to observing procedures stated in item 4., above. For secondary base stations, one of these connections must be to its nearest primary base station neighbor. Secondary base stations must be traceable back to two primary base stations along independent paths.
Local network stations must be traceable back to two base stations along independent paths.
The observing scheme for all stations requires that all adjacent stations (base lines) be observed at least twice on 2 different days and at two different times of the day according to observing procedures shown in item 4. on the previous page. The purpose is to ensure different atmospheric conditions (different days) and significantly different satellite geometry (different times) for the two base line measurements.
Observations on the second day should be completed between 27 and 33 hours after the completion of the first day's observations if the first day's observations were begun prior to 12:00 noon. Or, the observations should be completed between 15 and 21 hours after the completion of the first day's observations if the first day's observations were begun after 12:00 noon. This is necessary since the satellite constellation geometry repeats itself every 12 hours.


Examples: First-day observations Second-day observations
Begun during: Completed anytime between:
8:00 a.m. to 8:30 a.m. 11:30 a.m. and 5:30 p.m.
10:30 a.m. to 11:00 a.m. 2:00 p.m. and 8:00 p.m.
1:00 p.m. to 1:30 p.m. 4:30 a.m. and 10:00 a.m.
3:30 p.m. to 4:00 p.m. 7:00 a.m. and 12:30 p.m.
(Note that the second day of observations does not need to follow immediately after the first day. Satellite geometry moves ahead, or precesses, 4 minutes per day. If the second observations are not performed within 1 week of the first, this daily 4-minute change must be accounted for when meeting the different satellite geometry requirement.)

7. Selection of primary and secondary base stations in order of most-to-least- preferred are: 1. High Precision Geodetic Network (HPGN)/HARN (either Federal Base Network (FBN) or Cooperative Base Network (CBN) stations which have level ties to bench marks of A- or B-stability quality during this project; 2. bench marks of A- or B-stability quality or HPGN/HARN stations which were previously tied to bench marks of A- or B-stability quality; 3. User Densification Network (UDN)stations which have level ties made during this project; or 4. bench marks of C stability quality. In areas of known or suspected subsidence or uplift, special guidelines may need to be followed.
8. Data should be collected during periods when the Vertical Dilution of Precision (VDOP) is less than 6 for at least 90 percent of each 30-minute, or longer, observing period. For shorter observing periods, as in some projects where the 5-centimeter standard is the goal, a VDOP greater than 6 should be avoided entirely. Travel between stations could be scheduled during large VDOP periods.
9. For sessions greater than 30 minutes, collect data at 15-second epoch intervals, starting at an even minute. For sessions less than 30 minutes, collect data at 5-second intervals.
10. Track satellites down to at least a 10-degree elevation angle. (Note that tracking below 15 degrees may be helpful during processing when collecting data for less than 30 minutes.)
11. If possible, coordinate observations with local, existing CORS which are collecting phase data with dual-frequency receivers.
12. Meteorological data must be collected at the control stations and primary and secondary base stations. Weather data consist of wet- and dry-bulb temperatures (or dry-bulb temperature and relative humidity) and atmospheric pressure. For sessions greater than 2 hours, record weather data at the beginning, middle, and end of each session. For sessions that are less than 2 hours in length, but more than 30 minutes, record weather data at the beginning and end of each session. For sessions that are less than 30 minutes in length, collect data at the mid-point of the session. Meteorological data shall also be collected immediately after an obvious weather front passes during a session and also immediately before it passes, if possible. Atmospheric pressure measurements must be made at approximately the same height as the GPS antenna phase center. Record on the observing log the time and where the weather data were gathered, and any abnormal weather conditions.
(Note that even though all of these data may not used in the vector processing, they may be helpful during the analysis of the results and in future reprocessing with more robust software.)
Before taking weather observations, the meteorological instruments should be allowed ample time (approximately 10 minutes) to stabilize to ambient conditions. Observations of wet- and dry-bulb temperatures must be observed and recorded to at least the nearest 1 degree Celsius. Barometric readings must be observed and recorded to at least the nearest 1 millibar. Meteorological data should be collected at or near the antenna phase center. All equipment must be checked for proper calibration.
13. Antenna set-up is critical to the success of the project. Plumbing bubbles on the antenna pole of the fixed-height tripod must be shaded when plumbing is performed. Plumbing bubbles must be shaded for at least 3 minutes before checking and/or re-plumbing. The perpendicularity of the poles must be checked at the beginning of the project and any other time there is suspicion of a problem.
For the 2-Centimeter Standard: Fixed-height tripods are required for all receivers.
For the 5-Centimeter Standard: Fixed-height tripods are preferred for all receivers. When a fixed-height tripod is not used, the height of the antenna must be carefully measured to prevent station set-up blunders. Tribrachs used for these set-ups must be checked and adjusted when necessary. Totally independent measurements of the antenna height above mark in both metric units and English units must be made before and after each session. Someone other than the observer must check the measurement computations by carefully comparing measurements and then entering his/her initials on the log.
14. A rubbing of the mark must be made at each occupation of a station. When not feasible to make the required rubbing, a plan sketch of the mark must be substituted, accurately recording all markings.

Оффтоп

 

из практики: съемка в РТК, нет фиксации при съемке, все работает, кол-во спутников достаточное.
выключаем Глонасс - тут же пошла фиксация измерений и можно нормально работать.
мешался он...

 

вот так меряли gr3