Abstract: On the basis of the phase-differential locating equation obtained by the correspondence relationship between radial distance and phase, applying the trigonometric equation obtained by cosine law, the set of linear equation solving the target position can be obtained only by simple mathematical manipulation. Now, the location parameter of target can be solved and the accurate DF formula can be derived for the phase interference array with double baseline in one-di- mensional space. The verification for accurate solution and analysis for measuring error can be worked out by using the equivalence between path length difference and phase difference. But also, the analysis process is not related to the integer of wavelength and phase-differential measurement of discriminator. The study in this paper provides a theoretical basis for the correction of the measurement accuracy to the existing approximate solution obtained by the assumption of parallel incident wave.
After making the differential transformation for direction finding based on phase interferometry, the formula of angular velocity can be obtained by measuring frequency difference. Further, the measurement for frequency differ- ence can be transformed into phase difference measurement as soon as the function relationship between frequency shift and phase shift is introduced. The analog calculation validates that derived formula only based on phase difference measurement is correctness. The error analysis shows that the new method which has the performance of real-time measurement can achieve the measurement accuracy less than 1 mrad/s after synchronously calculating the measurement error of phase difference and airborne platform flight speed.
While the virtual short baseline is constructed by using the ratio subtraction in contrary terminal for adjacent two baselines, the differential of wavelength integer is not to zero in some arrival angle direction and but there is a jump. At the same time, there is also jump problem while using the DF result of virtual short baseline without phase ambiguity solves the phase ambiguity valuation of long baseline. The analysis in this paper shows that the emendation can be realized by distinguishing for the sinusoidal valuation of arrival angle. Also, the modifying factor is namely the proportional factor of differential between two baselines. Finally, applying the accurate DF formula explains in theory that higher accuracy of DF can be obtained by using two baselines arrays after revising without considering the phase error.