Gamma value for different terrains
G = surfacegamma(TerrainType)
G = surfacegamma(TerrainType,FREQ)
surfacegamma displays several terrain types and their corresponding values. These values are for an operating frequency of 10 GHz.
String that describes type of terrain. Valid values are:
Operating frequency of radar system in hertz. This value can be a scalar or vector.
Determine the value for a wooded area, and then simulate the clutter return from the area. Assume the radar system uses a single cosine pattern antenna element and an operating frequency of 300 MHz.
fc = 300e6; g = surfacegamma('woods',fc); hclutter = phased.ConstantGammaClutter('Gamma',g,... 'Sensor',phased.CosineAntennaElement,... 'OperatingFrequency',fc); x = step(hclutter); r = (0:numel(x)-1) / (2*hclutter.SampleRate) * ... hclutter.PropagationSpeed; plot(r,abs(x)); xlabel('Range (m)'); ylabel('Clutter Magnitude (V)'); title('Clutter Return vs. Range');
A frequently used model for clutter simulation is the constant gamma model. This model uses a parameter, , to describe clutter characteristics of different types of terrain. Values of are derived from measurements.
The values for the terrain types 'sea state 3', 'sea state 5', 'woods', 'metropolitan', and 'rugged mountain' are from .
The values for the terrain types 'farmland', 'wooded hill', and 'flatland' are from .
Measurements provide values of for a system operating at 10 GHz. The value for a system operating at frequency f is:
where is the value at frequency f0 = 10 GHz.
 Barton, David. "Land Clutter Models for Radar Design and Analysis," Proceedings of the IEEE. Vol. 73, Number 2, February, 1985, pp. 198–204.
 Long, Maurice W. Radar Reflectivity of Land and Sea, 3rd Ed. Boston: Artech House, 2001.
 Nathanson, Fred E., J. Patrick Reilly, and Marvin N. Cohen. Radar Design Principles, 2nd Ed. Mendham, NJ: SciTech Publishing, 1999.