SAS Above Water Optical System
The Surface Acquisition Systems (SAS) are designed for above-water measurements of ocean color using Sea-Bird Scientific's multispectral or hyperspectral digital optical sensors. The system consists of two radiance sensors and one irradiance sensor. The main advantage of the SAS system is its small size and extremely fast sampling rate. Special adapters can also be mounted to the SAS radiometer to narrow the field of view to a half angle of 1.5º to 0.75º. The HyperOCR SAS radiance sensors are designed with a narrow field of view compared to the in-water version and provide 136 channels of Li and Lt data.
The SAS can be mounted on a variety of vessels to provide continuous monitoring of ocean colour along the ship's track, on towers or other platforms to provide time series observations, or the system can be used for airborne remote sensing of ocean colour. See the SAS Solar Tracker product page for more information.
Applications:
-
Estimate concentrations of dissolved organic matter, suspended sediments, and chlorophyll
-
Bio-optical algorithm development and modelling
-
Satellite calibration and validation
-
Environmental monitoring
-
Data products include water leaving irradiance, remote sensing reflectance, and energy fluxes
Features:
-
Precision measurements of Li, Lt & Es
-
Adjustable viewing angles from Nadir to Zenith
-
Multiple radiometer options - multi, hyperspectral or combinations
-
Full ancillary suite - tilts, sea-surface temperature, GPS
-
Data logging and processing software included
| Irradiance in-air | Radiance in-air | |
| Field of View |
Cosine ±3% 0-60º 10% 60º- 85º (350-800 nm)
|
3º (FOV extension aperture) |
| Typical Saturation | 9 µW cm-2 nm-1 | 0.5 µW cm-2 nm-1 |
| SNR | 1.6 x 104 | 1.6 x 104 |
| Size |
39.9 (cm) Height 6.0 (cm) Diameter 1.0 (kg) Weight |
36.2 (cm) Height 6.0 (cm) Diameter 1.0 (kg) Weight |
| Operating Temperature | -10 to +50º | -10 to +50º |
SAS system deployed on the equatorial pacific |
SAS system for ocean color satellite calibration validation |
Water leaving radiance measurements in the Arctic |
Radiometers - Measuring Ocean Color |
Radiometers |
| Title | Type | Publication Date | PDF File |
|---|---|---|---|
| HyperSAS Datasheet | Product Datasheet | Friday, June 23, 2017 |
 datasheet-HyperSAS.pdf |
| SAS Manual | Product Manual | Thursday, June 22, 2017 |
Manual-SAS-SAT-DN-545.pdf |
| ProSoft User Manual | Software Manual | Wednesday, June 14, 2017 |
ProSoftUserManual7.7SAT-DN-00228.pdf |
| SatCon Manual | Software Manual | Wednesday, March 9, 2011 |
SatCon-Manual.pdf |
ProSoft 7.7.19 provides a number of key improvements including support for ancillary SAS sensors, support for BETA_IRED and BETA_GREEN sensors to calculate backscattering, corrected backscattering coefficient units, robust handling of corrupt timer data, HyperSAS IR camera integration, interruptable processing, and more. For a detailed list of recent fixes and features, please refer to the release notes.
ProSoft7.7.19-b2_Setup.exe for Windows 7/8/10SatCon is a software utility for converting raw binary data, as logged by SatView, into readable ASCII text suitable for import by third party applications such as spreadsheets or databases. Data can be extracted in calibrated physical units or raw binary counts. SatCon can be operated interactively through a user friendly graphical interface, or in batch mode as a background process.
For minimum system requirements, installation instructions, and new features, please refer to the release notes in the SatCon User Manual.
SatCon-1.5.5-b2-x86.exe for Windows 7/8/10What are SIP files?
Files that are delivered with Sea-Bird Scientific and third party equipment to describe the sensors data output and calibration coefficients come in two types. Calibration files or *.cal files and telemetry definition format files or *.tdf files. In some cases, systems are created that network many sensors together and their combined data is provided in one serial output. The simplest example is a HOCR sensor that generates both light and dark frames. A more complex example is a HPROII profiling system that may contain as many as 5 sensors and 7 individual calibration and tdf files. These files must be used to both collect and process the data. This can become quite confusing to keep track of all these files so Sea-Bird Scientific developed SIP files. All CAL and TDF files required for a system are zipped using winzip and the extension changed from *.ZIP to *.SIP. The file name includes the system description (usually the network master serial number) and the creation date. This SIP file can then be used in place of individual files to collect and process data.
What are the main differences between the multispectral and hyperspectral radiometers?
Sea-Bird Scientific multispectral 500 series radiometers measure light at each fixed wavelength with an interference filter/detector assembly. The analog output of each detector is amplified and digitized. The amplification stage and noise filtering is fine tuned for each wavelength to produce an optimal saturation limit and frame rate. This maximizes the signal to noise ratio while ensuring that each channel does not saturate during normal operations. The frame rate of each radiometer is fixed anywhere between 1 and 24 Hz depending on the customers specific requirements. 4 and 7 channel radiometers can be purchased in several configurations with different field of views. They have a small diameter to reduce self-shading and generate a digital output for stand-alone operations or they can operate as part of a larger 485 network of sensors (SATNet). 500 series sensors are also very low power devices making them excellent sensors for power limited platforms such as buoys, AUV’s and profiler floats.
Sea-Bird Scientific Hyperspectral HOCR radiometers use a Zeiss spectrograph optimally configured and characterized to measure light between 350 and 800 nm (approximately 136 individual channels). With the HOCR series, a variable integration time is used for all channels in the array and upper and lower thresholds are set so that no channel saturates within that array. Thermal dark current changes that occur within the spectrograph are corrected across the full spectrum with the use of a mechanical dark shutter that closes periodically in the radiometer. A separate frame of data is generated for this dark reading. Frame rates are dependent on the integration time of the device so are considered variable. When light levels are high, the integration time and frame rate are also high, so that you are collecting many frames per second. As the light level decreases, the integration time must increase and therefore the frame rate becomes longer. Integration times range from 4 ms to 2 seconds. HOCR sensors also have a small diameter to reduce self-shading and the same telemetry options are offered. Sea-Bird Scientific also offers a low power, non-SATNet version of the HOCR sensor for remote platforms that are power limited.
