A preliminary environmental assessment for the SPS points out that a variety of existing electromagnetic systems would be likely to experience SPS interference. Military communications equipment may be particularly sensitive to SPS interference. A study to characterize the SPS potential microwave interference has been completed and shows that there would be a significant potential interference with national defense requirements as represented by large military operational, test, and evaluation facilities. The performance of radar instruments used at airstrips and on test ranges to acquire and track targets could fall by 10 to 65 percent. The reception and reliability of command and control communications could be reduced by 5 to 30 percent, and tactical systems performance could be reduced greatly. If an SPS program is initiated, modifications or redesign of such equipment would be necessary to avoid degradation. It seems safe to assume that the SPS potential for interference with electromagnetic systems could be further enhanced with purposeful design to provide a potent ECM device. By way of comparison, a powerful airborne jammer with a directive antenna may be capable of providing an effective radiated power on the order of 50 kW within the SPS frequency range. Such a system may be expected to be effective to ranges on the order of 50 nautical miles or more. The power density at a 50-nautical-mile range from the jammer would be on the order of 4.6 x 10 11 . 2 watts/cm . This is much less than would be provided by the SPS microwave beam even if directed to locations other than the rectenna site. In addition, a single jammer can simultaneously engage a limited number of hostile systems. Using the SPS, it may be possible to disrupt hostile electronic systems over very large areas. C.4.2 EW Threats to the SPS The phase control system for the basic SPS is the most likely candidate for electronic warfare attack. If the phase control system is degraded sufficiently, the transmitter antenna subarrays will no longer be phased together and the SPS microwave power beam will be defocused. The phase control loop is composed of uplink pilot beam signals transmitted to receivers at each subarray of the SPS power beam transmitter. The SPS power beam constitutes a downlink which is sensed by a ground safety control system with command link capability to the satellite to automatically cease operations if need be.
RkJQdWJsaXNoZXIy MTU5NjU0Mg==