The Probe Aircraft Platform

The PROBE-1 hyperspectral remote sensing airborne system is an instrument which can deliver valuable information to clients in many industries, including mining, defense, agriculture, oil and gas, and environmental. The cost of data from the PROBE-1 and its fixed wing platform is substantially below that of existing satellite technology, creating a competitive advantage for ESSI’s customers in the race to learn the earth’s secrets.

Earth Search Sciences, Inc.’s hyperspectral remote sensing technology is helping revolutionize exploration from mining to oil and gas to agriculture. The potential is enormous. Earth Search technology is similar to DNA. The images are analyzed through special color processing to determine exactly what is on the ground. The PROBE-1 can locate mineral deposits and target geologic features with much greater accuracy and detail than other technologies.

The accuracy of the information provided though this breakthrough technology makes it difficult for anything—whether it’s pollution, precious metals or specific plant species—to hide from the PROBE-1.

Figure 1

The PROBE-1 Built by Integrated Spectronics for Earth Search Sciences, Inc.

Mounted on a stabilized platform, the PROBE-1 collects GPS data to reference the image data to GPS coordinates. The instrument utilizes four spectrometers and four lineal focal plan arrays to cover the 0.4 to 2.45 nanometer wavelength region.

The PROBE-1 can be flown over a range of altitudes to provide pixel sizes ranging from 1 to 10 meters and swath widths from <1 km to 6 km. At 2500 meters, the PROBE-1 has a swath width of 3 kilometers with a ground instantaneous field of view (GIFOV) of 5 meters (known as 5-meter resolution). From 5000 meters, the swath width is 6 kilometers with a GIFOV of 10 meters. Given the PROBE-1’s transportability between platforms, the lower pixel sizes are achieved by transferring the instrument to a slower flying platform such as a helicopter.

Many common minerals can be identified with the above performance. Ferrous (Fe2+) and ferric (Fe3+) bearing minerals have spectral features in the visible and near infrared region. Clay minerals can be identified with the spectral features in the shortwave infrared region. Carbonate minerals such as calcite and dolomite have features in the shortwave infrared region as well. Other minerals, including some sulfates, can be identified on the basis of signatures caused by water in their molecular structure.

Figure 2

Cuprite, Nevada – Natural Scene

Figure 2 shows a PROBE-1 image from a flight path over Cuprite, Nevada. This is produced in colors chosen to represent a natural looking scene, much like a natural photograph.

Software manipulation and a change in selection of the data and processing over the same area reveal a different look in Figure 3. Now, no longer a natural looking scene, the image reveals where the opalized rock and altered clays, kaolinite and alunite are actually located. The PROBE-1’s spectral resolution is sufficiently high that minerals with closely related spectral signatures like those above can be distinguished from one another. This process can go on and on over the same area as one looks for different materials.

Figure 3

Figure 4

Figure 4 shows where further analysis identifies buddingtonite, a much more important pathfinder mineral in geological exploration. It can be identified through the bright red color assigned to its spectral signature (Note: different colors can be assigned to the spectra for the sake of clarity, i.e., the same alunite is blue in one image and magenta in another)

In this same manner, different species of plants and trees can also be mapped.

The Probe-1 is a “whiskbroom style” instrument that collects data in a cross-track direction by mechanical scanning and in an along-track direction by movement of the airborne platform. The instrument acts as an imaging spectrometer in the reflected solar region of the electromagnetic spectrum (0.4 to 2.5 nm). In the VNIR and SWIR, the at-sensor radiance is dispersed by four spectrographs onto four detector arrays. Spectral coverage is nearly continuous in these regions with small gaps in the middle of the 1.4 and 1.9 nm atmospheric water bands.

In order to avoid geometric distortions in the recorded imagery, the Probe-1 is mounted on a 3 axis, gyro-stabilized mount. Geolocation of nadir pixels is assisted by the recording of aircraft GPS positional data and tagging each scan line with a time that is referenced to the UTC time interrupts from the GPS receiver.

Spectral Specifications (VNIR through SWIR )

Radiometric Calibration

Spectral Calibration

Spatial Specifications