System and method for in-place, automated detection of radome condition

#Weather radar systems used aboard commercial and private aircraft are dependant on transmissivity of the radome in front of the weather radar antenna to permit transmission and reception of weather radar signals. However, long exposure to impact by rain, hail, dust, and other objects can cause the protective outer surface of the radome to degrade or possibly delaminate. Specifically, the region at the front of the radome degrades faster then other portions of the outer surface of the radome due to driving rain. When the outer surface of the radome becomes degraded, water may then begin to penetrate the radome. The water is retained by the radome material and can degrade the transmissivity of the radome and, in turn, the sensitivity of the radar. In operation, it is not apparent to the radar operator that water penetration has occurred or that possible degradation of radar performance may have occurred.

#As currently known in the art, radomes are routinely removed on the ground for inspection, replacement, or reinstallation. For example, testing of radomes using currently known methods entails removing the radome from the aircraft, placing the radome on a test set, and measuring transmissivity of the radome by measuring the loss from one antenna placed inside the radome and a second test antenna just opposite and outside the radome. Such maintenance work removes the aircraft from service, costing time and money that may be unnecessarily spent. Further, improper repairs made to a radome after substantial damage, such as that from a bird strike, can result in distortion of antenna beams and poor transmissivity. Such problems may not be detected until the next scheduled maintenance.

#In addition, conditions that cause poor radome performance in operation, such as wetting of the outer surface due to rain, may not exist on the ground where the radome is tested. In such a case, the radome may be erroneously approved for return to service.

#The preferred and alternative embodiments of the present invention are described in detail below with reference to the following drawings.

#FIG. 1 is a side view of the invention installed on a host radar system;

#FIG. 2A is a side view of the invention installed on a host radar antenna;

#The present invention provides a system and method for automated in-place detection of radome condition. The invention measures variable reflectivity of a radome directly in front of a typical weather radar antenna by using a radar that operates at a frequency that involves multiple half-wave lengths of the radar antenna.

#Referring to FIG. 1, a system 10 for performing automated in-place detection of condition of a radome 12 includes an antenna 14 and radar circuitry 16. The antenna 14 and the radar circuitry 16 are mounted on a host antenna 18, such as an antenna for a weather radar system. As is known, the host antenna 18 is mounted on an antenna gimbal 20 that is in turn mounted to an aircraft bulkhead 22. As is known, the antenna gimbal 20 causes the host antenna 18 to scan throughout azimuth and elevation angles. Thus, when the host antenna 18 is scanned throughout azimuth and elevation angles by the antenna gimbal 20, the antenna 14 of the system 10 in turn scans the radome 12.

#The system 10 is suitably a frequency modulation/continuous wave (FM/CW) radar system. Range resolution of the system 10 is suitably commensurate with a minimum range from the antenna 14 to the radome 12. Typical distances between the antenna 14 and the radome 12 are generally three feet or less. Further, the antenna 14 is preferably sized to be small enough such that the antenna 14 operates in its far field at the distance from the antenna 14 to the radome 12. To achieve both the far field criteria and the range resolution criteria, the system 10 is preferably realized as an FM/CW radar operating in the millimeter wave frequency range of about 30 GHz.