What is the static method of GPS Surveying
Static Surveys
The Static surveys offer the 2nd highest precision of static surveys by occupying a single location for the occupation times ranging from two to 48 hours. When processed through OPUS, static surveys have the maximum accuracy of ~ one –two cm, depending on the quality and length of the data collection. This is most comparable to the accuracies achievable by PPK systems with long baselines, but in the general PPK surveys are recommended if the local base station with short baseline is possible. Static surveys are conducted and processed in same way as the rapid static survey, but typically use higher-precision mounts and the more equipment, such as large batteries, solar panels, and the equipment enclosures to support the GNSS receivers during the length of survey. The amount of the equipment needed increases with increased occupation times. See Section 2.3 for advice on batteries and the length of surveys with some known hardware configurations.
Continuous Surveys (Semi-permanent to the Permanent Stations)
Semi-permanent to the permanent surveys involve extended deployment of the station beyond forty eight hours and the potentially for many years. The advantage of the permanent survey is continuous data collection, which enables high-precision (mm-scale) positioning and potential for the monitoring an area beyond what is the practical for the single field deployment. These installations require significant knowledge in the geodesy and processing techniques, which are not included in this guide. However, field techniques for the site selection, logistics, installation, and the execution are similar and can be applied for the whole range of the applications. In the general, the additional hardware requirements of permanent installations include precision mounting devices, extended battery banks, and the solar panels or other auxiliary power charging units.
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The Static surveys offer the 2nd highest precision of static surveys by occupying a single location for the occupation times ranging from two to 48 hours. When processed through OPUS, static surveys have the maximum accuracy of ~ one –two cm, depending on the quality and length of the data collection. This is most comparable to the accuracies achievable by PPK systems with long baselines, but in the general PPK surveys are recommended if the local base station with short baseline is possible. Static surveys are conducted and processed in same way as the rapid static survey, but typically use higher-precision mounts and the more equipment, such as large batteries, solar panels, and the equipment enclosures to support the GNSS receivers during the length of survey. The amount of the equipment needed increases with increased occupation times. See Section 2.3 for advice on batteries and the length of surveys with some known hardware configurations.
Continuous Surveys (Semi-permanent to the Permanent Stations)
Semi-permanent to the permanent surveys involve extended deployment of the station beyond forty eight hours and the potentially for many years. The advantage of the permanent survey is continuous data collection, which enables high-precision (mm-scale) positioning and potential for the monitoring an area beyond what is the practical for the single field deployment. These installations require significant knowledge in the geodesy and processing techniques, which are not included in this guide. However, field techniques for the site selection, logistics, installation, and the execution are similar and can be applied for the whole range of the applications. In the general, the additional hardware requirements of permanent installations include precision mounting devices, extended battery banks, and the solar panels or other auxiliary power charging units.
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Thumb Rules for Civil Engineers And Quantity Surveyors
Equipment
Various types and combinations of the antennas, receivers, and controllers are available in the modern market and are constantly evolving. Generally, it is easiest to the work with antennas and receivers from same manufacturer, unless other compatibility is the specifically mentioned, although the data is the completely interchangeable once retrieved and processed. The Earth Scope supported projects receive Topcon, Trimble, or Septentrional branded units. Because processing software and the workflow is manufacturer dependent, instructions provided here are manufacturer independent. The general workflow should apply to the most manufactures, but see manufacturer literature or the GAGE Knowledge Base for the specific instructions.
Antennas
Antennas are the physical equipment that receive the carrier frequency & the positioning code from the satellites & the transmits it to the receiver for the processing (Figure two). Antennas may consist of just an antenna or include `1 or more signal-modifying or blocking apparatus, which are aimed at the reducing or enhancing multi-path signals and the atmospheric distortion. Some modern antennas, such as the Septentrional APS-three (Figure two, left), have the combined antenna and receiver unit in 1 package, sometimes referred to as the smart antenna.
Receivers
Receivers are the central processing units of GNSS system
(Figure three). They connect the various other hardware including
antennas, radios, and the power. They receive signals from the antenna
and compare the satellite and the receiver time codes to calculate distance
between them. This time differential is fed into the complex code for
determining position based on at least four satellite signals. Positional
data may be stored in the various formats, most of which are proprietary
for each manufacturer. The receiver is responsible for the sending the
position data to the controller computer for user viewing and for
taking user input and executing commands.
Power & Batteries
Receivers, antennas, & controllers use both internal and external batteries for the power. Average running time for batteries depends on the manufacturer design but typically last four – ten hours for internal setups, with external setups limited only by ability to the transport larger batteries to the site (Table one ). Battery technology will depend on the environmental conditions. Gel cell and LiPo batteries have the advantage of the being environmentally stable and the spill-proof. Battery estimates need to be made based on the power draw of the equipment. A simple formula for the estimating battery consumption is Total Amperage (Volt*Watts) * Total Operational Time and (hours) = Battery Capacity (Amp/Hrs) Capacity should be overestimated to the account for logistical oversight or complications, keeping in mind the battery capacity is reduced over time with use. Power can also be supplemented by many means including solar and wind, or other power sources as demanded by the site. For more info on alternative power, see the Earth-Scope Resources.
Receivers, antennas, & controllers use both internal and external batteries for the power. Average running time for batteries depends on the manufacturer design but typically last four – ten hours for internal setups, with external setups limited only by ability to the transport larger batteries to the site (Table one ). Battery technology will depend on the environmental conditions. Gel cell and LiPo batteries have the advantage of the being environmentally stable and the spill-proof. Battery estimates need to be made based on the power draw of the equipment. A simple formula for the estimating battery consumption is Total Amperage (Volt*Watts) * Total Operational Time and (hours) = Battery Capacity (Amp/Hrs) Capacity should be overestimated to the account for logistical oversight or complications, keeping in mind the battery capacity is reduced over time with use. Power can also be supplemented by many means including solar and wind, or other power sources as demanded by the site. For more info on alternative power, see the Earth-Scope Resources.
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Data Management, Storage, & Initial Settings
Data management is the small but critical step in the survey design. It is ineffective to have the well-designed survey only to find out you have run out of the storage space, lost the data, or collected improper occupation lengths for precision needed. Each unit has the unique set of the capabilities and limitations (Table 2). Consider the following:
• File length –
do u want the receiver to bin the data into the files of a fixed time window.
• Sample rate –
how often do u want the receiver to collect data The base station (fast static & kinematic surveys) must collect data at least as often as rover(s). A kinematic rover will typically collect one sample/second for the total occupation at each site of five – fifteen seconds.
• Elevation cutoff angle –
data coming from low-elevation satellites is often noisy because of atmosphere; below what elevation do u want the receiver to discard, rather than store data? Note that this data can also be discarded during processing. A typical value is five –10°
• Storage Capacity –
There must be enough free memory in receiver for the desired survey. Whereas memory is an the issue with older receivers, the later generation receivers have large amounts of the data storage. File size is dependent on the manufacturer file formatting. Note the Topcon collects half as much data at the thirty -second sample rate (versus fifteen -second on Trimble), but produces the larger file. Upgraded storage space is the relatively cheap and easy to acquire
Data management is the small but critical step in the survey design. It is ineffective to have the well-designed survey only to find out you have run out of the storage space, lost the data, or collected improper occupation lengths for precision needed. Each unit has the unique set of the capabilities and limitations (Table 2). Consider the following:
• File length –
do u want the receiver to bin the data into the files of a fixed time window.
• Sample rate –
how often do u want the receiver to collect data The base station (fast static & kinematic surveys) must collect data at least as often as rover(s). A kinematic rover will typically collect one sample/second for the total occupation at each site of five – fifteen seconds.
• Elevation cutoff angle –
data coming from low-elevation satellites is often noisy because of atmosphere; below what elevation do u want the receiver to discard, rather than store data? Note that this data can also be discarded during processing. A typical value is five –10°
• Storage Capacity –
There must be enough free memory in receiver for the desired survey. Whereas memory is an the issue with older receivers, the later generation receivers have large amounts of the data storage. File size is dependent on the manufacturer file formatting. Note the Topcon collects half as much data at the thirty -second sample rate (versus fifteen -second on Trimble), but produces the larger file. Upgraded storage space is the relatively cheap and easy to acquire
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