The DAQ-A-SD is an aerodynamic PPK data logger containing GNSS (GPS) and IMU position sensors, with a user-accessible micro SD card for saving the data log. An integrated, downwelling SPECTROMETER 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.

Main Features:

• The DAQ-A-SD continuously saves the sensor data from the GNSS, IMU and SPECTROMETER, as well as the PWM (camera trigger) and EXP (camera exposure) events.

• A large spectrum coverage (340 - 1010 nm) means you only need one DAQ-A-SD to support calibrating every model of Survey3 we offer (RGN, OCN, NGB, RE, NIR). A single log file can correct any number of Survey3 cameras.

• The removable micro SD memory card stores data log files and the user-editable DAQ configuration file. Log file is used in MAPIR software to improve the image geolocation information (PPK), as well as adjust the calibration over time.

• Camera trigger signals are sent with each DAQ-A-SD button press, or at set time intervals. The user can easily adjust the triggering rate interval by editing the configuration text file on the memory card.

• Support for 2 separate Survey3 camera exposure logging. This allows for more accurate image geolocation metadata updates during post processing (PPK).

• Daylight readable RGB LED button shows system status. LED brightness is adjustable and disableable. Button triggers cameras and turns logging on/off.

• DAQ-A-SD can be conveniently powered by 1 or 2 Survey3 cameras, or using the side USB port.

• Automatically syncs connected Survey3 camera system clock time (RTC). Make sure cameras are set to time zone GMT-0.

• Easy firmware updates using firmware file on the SD card.

Mounting Options:

Designed into the bottom of the DAQ-A-SD are rails that mate with our various DAQ-A-SD mounting plates. Simply pull the tab on the plate down and slide the DAQ-A-SD into the mount. We offer mounts that contain multiple through-holes, a 1/4-20 threaded tripod hole, and drone specific models (DJI Mavic 3, etc). You can also use double-sided tape (not included) to attach to any surface.

Power Options:

You can power the DAQ-A-SD using the side USB port OR the rear Survey3 camera connection ports. If using short 10" cables you can use a single Survey3 camera to power the DAQ-A-SD. If you use longer cables you will need 2 Survey3 cameras, or USB power. Never apply power to BOTH the USB and camera ports. Runtimes below are for continuous RAW image capture (every 3s). 

Survey3 Camera Connection Ports:

Example Spectrometer Scan:

Sunlight

Specifications:

Included:

1 x DAQ-A-SD data logger

1 x 16GB micro SD card (+ SD adapter)

1 x Micro USB power cable

MAPIR's new light sensor (spectrometer) 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. Shadows, such as clouds in front of the sun, and from objects such as the tall wooden stake in the top right of the scene do not affect the contrast measurements. As the sun sets the shadow from the stake sweeps across the scene, but the NDVI of the grass (green = healthy) does not change when using both our target and light sensor for calibration.

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

Using the MAPIR light sensor on an aerial vehicle allows you to capture images no matter the weather. Shadows from clouds or tall objects are greatly reduced, allowing consistent data capture in most lighting conditions. The above NDVI images show rows of alfalfa agricultural crops from 400ft, and consist of many individual images that have been stitched together to make a map. Even though there was cloud cover, with the sun going behind the clouds during the mapping mission, the resulting NDVI contrast map is similar to the next day when the sky was clear.