Location
Cocoa Beach, FL
Start Date
5-4-1965 8:00 AM
Description
The Eastern Test Range (ETR) has recently experienced increasing demands for signature data. Satisfying these demands requires the use of specialized equipment, techniques, and personnel of varied backgrounds. Since this capability has recently been expanded here at the ETR, it is the intent of this paper to present a broad survey of the techniques and equipment being used. Because of the complexity of the subject matter and security requirements it was necessary to avoid greater detail. Much of the information presented here was extracted from unclassified sources and the figures and data that describe the hypothetical test are based on several different tests. These data have been completely modified so that they do not reflect the characteristics of any specific vehicle or test.
Signature Analysis (SA) is a technique which uses various sensing devices (radar, optoradiometric) in attempts to identify unknown objects in space and during re-entry. Identification is based upon characteristic signal returns for a specific sensing device. For example, using radar one can determine, to a certain degree, the size and shape of an unknown object by analyzing AGC records or video returns.
Figure 1 shows characteristic returns from a sphere and a tumbling cylinder. The reason the amplitude of the sphere is relatively constant (neglecting range) is that regardless of the position of the sphere relative to the radar beam, the cross-sectional area of the reflecting surface is always constant. However, this is not the case for any geometric shape other than a sphere. In these cases the amplitude of the returned signal is a function of the aspect angle and the physical size and shape of the object being tracked. The pattern presented in Figure 1 represents a tumbling cylinder moving directly toward the tracking source. The four major peaks represent a 360° rotation of the cylinder, with each of the peaks indicating maximum signal return from broadside and end-on views of the cylinder to the radar beam. The lobe widths and relative amplitudes are functions of a number of variables among which are body shape and radar frequency.
Signature Studies for a Re-Entry System
Cocoa Beach, FL
The Eastern Test Range (ETR) has recently experienced increasing demands for signature data. Satisfying these demands requires the use of specialized equipment, techniques, and personnel of varied backgrounds. Since this capability has recently been expanded here at the ETR, it is the intent of this paper to present a broad survey of the techniques and equipment being used. Because of the complexity of the subject matter and security requirements it was necessary to avoid greater detail. Much of the information presented here was extracted from unclassified sources and the figures and data that describe the hypothetical test are based on several different tests. These data have been completely modified so that they do not reflect the characteristics of any specific vehicle or test.
Signature Analysis (SA) is a technique which uses various sensing devices (radar, optoradiometric) in attempts to identify unknown objects in space and during re-entry. Identification is based upon characteristic signal returns for a specific sensing device. For example, using radar one can determine, to a certain degree, the size and shape of an unknown object by analyzing AGC records or video returns.
Figure 1 shows characteristic returns from a sphere and a tumbling cylinder. The reason the amplitude of the sphere is relatively constant (neglecting range) is that regardless of the position of the sphere relative to the radar beam, the cross-sectional area of the reflecting surface is always constant. However, this is not the case for any geometric shape other than a sphere. In these cases the amplitude of the returned signal is a function of the aspect angle and the physical size and shape of the object being tracked. The pattern presented in Figure 1 represents a tumbling cylinder moving directly toward the tracking source. The four major peaks represent a 360° rotation of the cylinder, with each of the peaks indicating maximum signal return from broadside and end-on views of the cylinder to the radar beam. The lobe widths and relative amplitudes are functions of a number of variables among which are body shape and radar frequency.
