Abstract: A method and apparatus to determine angles .theta..sub.1 and .theta..sub.2 between paths of two sets of reflected radar waves and a radar boresight utilizes the electrical angles .beta..sub.1 or .beta..sub.2 and two successive radar target observations. One set of radar waves may travel a path from a target and the second set may travel a multipath from the same target. Alternatively, the two sets of radar waves may follow direct paths from two targets. For coherent radar hardware, signals from two halves of an array are processed through a linear coherent receiver, analog-to-digital converter and processing unit with associated memory. The memory contains a database and program which calculates the electrical angles .beta..sub.1 and .beta..sub.2 and angles .theta..sub.1, and .theta..sub.2. For non-coherent radar hardware, mixers, a phase detector and two magnitude detectors are substituted for the linear coherent receiver.

Abstract: A radar system for determining not only the azimuth and range of a target but also the target height over a predetermined range of elevation angles has separate receiving and signal processing channels coupled to a dual beam antenna for processing signals returned from a single target. The output of each signal processor is coupled to a height processor which divides the sum of the received signals into the difference of the two signals. The resulting ratio is used to access a look-up table to identify the elevation angle associated with the ratio from which the height of the target is calculated. The look-up table includes correction values to compensate for the antenna pattern nonlinearity.

Abstract: Where reflection coefficient k of the surface of the sea is in a relatively wide range and as the ratio of the antenna height to the wavelength is larger, a radar system can eliminate ambiguities in measuring a target height of a low elevation angle on the sea surface. An antenna receives two beams, one beam having slightly different elevation angle from the other. An antenna direction adjusting mechanism adjusts, on the basis of tan.sup.-1 (ha/R), a direction in which receiving sensitivity of one of the beams is equal to receiving sensitivity of the other beam, so that this direction aims at mid point between the target and the image of the target. The phase difference between the two beams is obtained with respect to two different frequencies. Two series of data of the target height are obtained each on the basis of the respective phase difference.