LIVAR® Field Test

Intevac conducted field trials of its Laser Illuminated Viewing and Ranging (LIVAR®) target identification system during October of 2001 at San Francisco Bay in Northern California. A LIVAR system utilizing Intevac's Model 120 LIVAR camera was used for the demonstration. A photograph of this system is shown in Figure 1.

Figure 1: Intevac LIVAR System

Field Test Conditions

During the field test, the LIVAR system was located in the city of Tiburon, at water's edge and approximately 15 feet above sea level. Figures 2 , 3 and 4 show a map and daytime photographs of the field test location and the "target" for the field test, a 42 foot sailboat. The LIVAR imagery shown was collected after dark. Since LIVAR does not require any visible light, nighttime imagery is essentially identical to what can be achieved during daytime. A portable Forward Looking Infrared (FLIR) system with wide field of view was used to determine the bearing to the target prior to aiming the LIVAR system.

Figure 2: San Francisco Bay LIVAR Data Collection Test Site

Figure 3: San Francisco Bay LIVAR Data Collection Test Site

Figure 4: Daytime Photo of Sailboat Used for San Francisco Bay LIVAR Data Collection

Figures 5 & 6 were taken at a range of 600 meters. In Figure 5, the registration number of the boat, printed with 3-inch high letters, is clearly readable. You can also see a person standing on the deck of the boat with a handgun in his waistband. Figure 6 shows the same person with an assault rifle.

Figure 5: LIVAR Image of Boat Registration Number with Handgun at 600 Meters

Figure 6: LIVAR Image of Man with Assault Gun On Deck of Boat at 600 Meters

Figures 7 & 8 were taken at a range of 1 kilometer and show a scuba diver going into and out of the water.

Figure 7: LIVAR Image of Scuba Diver Entering Water From Back of Boat at 1 Kilometer

Figure 8: LIVAR Image of Scuba Diver Exiting Water With Assault Gun at 1 Kilometer

Figures 9 & 10 were taken at a range of 1 kilometer and show various personnel on the boat. It was easy to determine how many people are on the boat, in addition to the activities they were performing. The name of the sailboat is also legible.

Figure 9: LIVAR Image of Three Men on the Stern of the "Tantara" at 1 Kilometer

Figure 10: LIVAR Image of Man Wearing Gas Mask and Carrying an Assault Gun on the Bow of the Boat at 1 Kilometer

Figures 11 - 14 illustrate the impact of frame averaging to reduce the effects of atmospheric turbulence and improve the quality of the LIVAR image. Figures 11 & 12 show how the boat registration number is legible at a range of 1 kilometer after averaging several frames of video. Figures 13 & 14 show the same effect at a longer range of 2 kilometers.

Figure 11: LIVAR Image of Boat Registration Number (Single Frame) at 1 Kilometer

Figure 12: LIVAR Image of Boat Registration Number (8-frame Average) at 1 Kilometer

Figure 13: LIVAR Image of Two Men on the Stern of the "Tantara" (Single Frame) at 2 Kilometers

Figure 14: LIVAR Image of Two Men on the Stern of the "Tantara" (8 Frame Average) at 2 Kilometers

Technical Details

The laser power used for this data collection was varied from 10mJ to 60mJ per pulse from a KTP OPO shifted Nd:YAG laser at 1.57µm wavelength, and all of the images were taken with a 200mm aperture (2000mm focal length, f/10), Schmidt-Cassegrain lens. It should be noted that water is extremely absorptive at the 1.57µm illumination wavelength and results in very high target-to-background contrast.

System parameters are given in Table 1.