— Frequently Asked Questions —
- 1.Guangzhou Geosurv InformationTechnology Co., Ltd
Guangzhou Geosurv Information Technology Co., Ltd is a professional company specialized in high accuracy surveying, measuring and monitoring solutions, especially focuses on providing practical, cost effective and innovative monitoring solutions for geotechnical engineering.
- 2.Payment Method
Due to frequent network fraud recently, please do not believe the change of the receiving account notified by our company. Our company has only two receiving accounts, which will not be changed in a short time, they are
A：GUANGDONG FOREIGN TRADE IMPORT & EXPORT CO.,LTD.
B：GUANGZHOU GEOSURV INFORMATION TECHNOLOGY CO.,LTD
If we really need to change the payment method, we will inform you through the official website, email, What's App, Wechat and other channels.
Please stay alert and contact us if you find anything suspicious.
- 3.How many channels are required in a GNSS receiver?
The number of channels required in a GNSS (Global Navigation Satellite System) receiver depends on the specific application and the GNSS system used.
For GPS (Global Positioning System) receivers, a minimum of 4 channels are needed to determine the user's position in 3D (latitude, longitude, and altitude). Additional channels provide increased accuracy and faster time-to-first-fix.
For multi-constellation GNSS receivers, more channels are required to receive signals from multiple satellite constellations such as GPS, GLONASS (Russian Navigation Satellite System), Galileo (European GNSS system), BeiDou (Chinese GNSS system), and QZSS (Japanese GNSS system). The exact number of channels needed can vary depending on the system's design, the number of visible satellites, and the receiver's position.
In general, GNSS receivers with more channels provide better accuracy, faster time-to-first-fix, and improved coverage in challenging environments.
- 4.What are the field procedures in Static GNSS surveys?
The field procedures in static GNSS surveys typically include the following steps:
1.Site preparation: Choose a clear and open sky view and ensure that the GNSS receiver has a clear line of sight to the satellites.
2. Receiver setup: Turn on the GNSS receiver and configure it for static surveying mode.
3. Initialization: Let the GNSS receiver collect enough data to calculate an initial position.
4. Occupation: Collect GNSS observations at the survey point for a sufficient amount of time, usually 30 minutes to several hours.
5. Post-processing: Transfer the collected GNSS data to a computer for post-processing to compute the final position of the survey point with higher accuracy.
6.Quality control: Verify the quality of the GNSS data and check for any issues, such as multipath errors or satellite outages.
7. Repeat the process for additional survey points to create a network of accurately surveyed points.
It is important to follow best practices for GNSS surveys, such as proper instrument setup and accurate data collection, to ensure the highest level of accuracy and reliability in the survey results.
- 5.What are sources of errors in satellite surveys?
There are various sources of errors in satellite surveys,including:
1. Orbit and attitude errors: The satellite's orbit and orientation can cause inaccuracies in the data collected.
2. Instrumental errors: The sensors and instruments on the satellite can have errors in calibration or measurement.
3. Data processing errors: Errors can occur during the processing of the raw data collected by the satellite into a usable format.
4. Atmospheric effects: The Earth's atmosphere can cause scattering and absorption of the signals from the satellite, leading to errors in the data.
5. Geometric distortions: The curvature of the Earth and the satellite's viewing geometry can cause geometric distortions in the data.
6. Ephemeris errors: Inaccuracies in the satellite's position information can cause errors in the data collected.
7. Data transmission errors: Errors can occur during the transmission of the data from the satellite to the ground, affecting the accuracy of the data.
8. Terrain-related errors: The presence of terrain features such as mountains or valleys can cause shadowing or occlusion of the satellite signals, leading to errors in the data.
- 6.Instrumental Errors in a Satellite Surveys?
Instrumental errors in satellite surveys refer to inaccuracies in the data collected by the sensors and instruments on the satellite. These errors can be caused by several factors, including:
- Calibration errors: Incorrect calibrations of the sensors can lead to errors in the data collected
- Sensor drift: Over time, the sensors can drift and lose accuracy, leading to errors in the data.
- Non-linearity: The sensors may not have linear responses to changes in the signal, leading to inaccuracies in the data.
- Electronic noise: The electronic components of the sensors can generate noise that affects the accuracy of the data.
- Data quantization: The process of converting continuous signals into digital form can cause errors due to quantization
- Dynamic range: The sensors may not have the sufficient dynamic range to accurately measure signals with a wide range of intensities.
- Bandwidth limitations: The sensors may have limited bandwidth, affecting their ability to Load failed accurately measure high-frequency signals.
- Interference: Interference from other signals or sources can affect the accuracy of the data collected by the sensors.
- Spectral response: The sensors may have different responses to different frequencies of light or radiation, leading to inaccuracies in the data.
- Aging: Over time, the sensors and instruments can deteriorate, affecting their accuracy and leading to errors in the data It is important to continuously monitor and calibrate the sensors and instruments to minimize instrumental errors in satellite surveys.
- 7.Mistakes in Satellite Surveys
Mistakes in satellite surveys can occur due to several factors, including human error, technical errors, and errors in data processing and analysis. Some common mistakes include:
1.Incorrect satellite configuration: The satellite may not be set up correctly, leading to errors in the data collected.
2. Data collection errors: Errors can occur during the data collection process, such as missing or corrupted data.
3. Incomplete data coverage: The satellite may not collect data for a complete area, leading to incomplete or inaccurate results.
4. Data processing errors: Errors can occur during the processing and analysis of the data, such as incorrect algorithms or incorrect data inputs.
5. Inadequate data quality control: Proper quality control processes may not be in place to identify and correct errors in the data.
6. Inaccurate ground control points: The ground control points used for referencing the data may not be accurate, leading to errors in the results.
7. Inadequate training: Personnel may not be properly trained in the use of the satellite and its data, leading to errors in the results.
To minimize mistakes in satellite surveys, it is important to have proper planning, training, and quality control processes in place. Regular monitoring and maintenance of the satellite and its instruments are also important to ensure accurate data collection.
