Radar and Measurement Technology

Ground & Foliage Penetration

SPC has conducted radar penetration measurements from both airborne and ground-based platforms.

Air-to-Ground Penetration
Helicopter with deployed radar system
Helicopter with deployed radar system

SPC has a growing program in performing ground and foliage penetration, primarily from airborne platforms. Currently, the platform being used is a UH-1 Huey helicopter, configured with a palletized MkV radar.

The initial configuration for this system used horizontal (H) and vertical (V) polarized log dipole antennas and step-chirped the transmit signal over the frequency range from 150 - 450 MHz. Some steps in the chirp were suppressed to make the radar conform to FCC frequency clearance requirements. Data were collected for SAR imaging in both HH and VV mode.

In this configuration, data at 1 m resolution were acquired over 10 square miles of terrain in Oklahoma. Data from this initial configuration were processed using both tomographic and range migration algorithms.

After completion of this first project, a number of adjustments were made to the system configuration. The most important of these changes was replacing the log periodic antennas with an array of crossed dipoles to improve the system gain and allow efficient collection of crossed-polarization data. Also, the mounting structure was re-designed to be carried beneath the skids and jettisoned in case of an emergency.

Ground-to-Ground Penetration
Truck and trailor with deployed radar system

SPC has deployed its MkV in a truck-based configuration for SAR measurements. This provides an inexpensive mobile testbed for measurements ranging from 150 MHz to 18 GHz and 33.5 GHz to 36.3 GHz.

The platform features include:

  • Ample workspace
  • A/C and heat
  • Overhead lighting
  • Lift-gate
  • Portable generator
  • Side access door
  • Reinforced roof for El/Az antenna mount
  • Fixed-azimuth antenna mount on lift-gate provides +/- 90 degree elevation adjustment
  • GPS positioning

Applications include:

  • Simulated airborne SAR without the cost of flight time
  • Ground-to-ground SAR obscuration and penetration studies
  • Nadir-looking ground-penetrating SAR