Multispectral Ambient Light Sensors
The DAQ-A is an aerodynamic PPK data logger containing GNSS (GPS) and IMU position sensors, with a user-accessible memory card for saving the data log. The DAQ-A-SD adds an integrated, downwelling SPECTRORADIOMETER which records the changing ambient light spectrum (340 - 1010 nm) to assist with calibrating Survey3 camera images. There is a USB port for power input, an RGB LED status button and two Survey3 camera connection ports (power + signals).
Maintains Contrast
In Varying Light Conditions
(Scroll Down for More Samples)
Terrestrial Remote Sensing
Specifications:
| Spectroradiometer Calibration | Wavelength Alignment (Channel to Channel) |
| Calibrated Image Pixel Units | Percent Reflectance |
| Wavelength Range | 340 - 1010 nm |
| Wavelength Measurement Width | 5 nm |
| Number of Measurements Recorded | 134 |
| Wavelength Resolution | 20 nm - 50 nm |
| Wavelength Accuracy | 3 nm |
| Repeatability (peak) | 1 nm |
| Measurement Power Range | 20 - 150,000 Lux (PPFD: 0 -2,000 μmol) |
| Total Measurement Speed | ~ 900ms |
| Signal to Noise Ratio | 250 : 1 |
| Dynamic Range | > 1000 : 1 |
| Linearity | 99% |
| Integration Time | Auto, or Custom (0.25 ms - 100 ms) |
| Logging Rate | 1 Hz |
| Diffuser | Glass Cosine Corrector |
| Field of View | <180 degrees |
| GNSS Receiver (Advanced V2) | ublox MAX-M10S, |
| Satellites Supported | GPS, BEIDOU, GALILEO, QZSS, SBAS |
| Antenna | Ceramic Patch (25 x 25 x 4 mm ) |
| Sensitivity | -165 dBm |
| Channels | 210 PRN |
| Logging Rate | 4 Hz |
| GNSS Positional Accuracy | 1.5m |
| Top GNSS Status LEDs | Power (green), GPS lock (blue) |
| IMU Positional Sensor | BNO085, 9-axis DoF |
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Memory Storage
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Micro SD Card (16GB INCLUDED)
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Memory Format Supported
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exFAT, FAT32, NTFS
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Memory Capacity Supported
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Up to 512GB
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Logging Duration
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16GB = ~135 days, 128GB = ~3 years, 512GB = ~12 years
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Camera PWM Trigger Interval
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1+, Customizable (in seconds, any duration)
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Camera Exposure Pulse Detection
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3V3 Relay (High)
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Power Input - Max Current
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5.0V - 0.26A
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Runtime (1x Survey3 Camera Battery)
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45 minutes
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Runtime (2x Survey3 Camera Battery)
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120 minutes
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Dimensions
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78.6 x 36.0 x 25.7 mm (L x W x H)
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Weight
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DAQ-A (57g), DAQ-A-SD (60g)
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Our light sensor (spectroradiometer) maintains our reflectance calibration when the ambient light changes.
Below you can see a 3.5 hour time lapse animation with an image captured each minute during partly cloudy weather. The scene is composed of healthy grass with some dead leaves. The images have been processed with a color gradient to show a range from healthy plants (green) to unhealthy/dead plants (red) using the NDVI formula. The 4 sections show the original images, the NDVI when not calibrated, the NDVI when calibrated only with our reference targets and the NDVI when calibrated with both our target and light sensor.
Below: Survey3W OCN, 3.5 hour time-lapse (1 photo/min, 206 frames), Locked Exposure, Cloudy Weather, NDVI LUT 0.2-0.8 [Resolution Reduced for Web Viewing]
Notice how the original images change in brightness constantly as the clouds move in front of the sun. Our light sensor tracks the changes in the ambient light and keeps the index (NDVI) contrast measurements consistent.
Below: Survey3W RGN, 3.5 hour time-lapse (1 photo/min, 206 frames), Locked Exposure, Cloudy Weather, NDVI LUT 0.2-1.0 [Resolution Reduced for Web Viewing]
Survey3W RGN (Left to Right) Original JPG, Calibrated RAW, NDVI LUT 0.2-1.0
Below: Survey3W RGN, Alfalfa Field 400ft, Cloudy vs Sunny Weather, NDVI LUT 0.2-1.0
