Простой модуль локационных измерений доплеровского сдвига частоты и угла прихода на основе двухканальной поляризационной тандемной амплитудно-фазовой модуляции. Часть 2
Authors: Морозов О.Г. , Морозов Г.А. , Ильин Г.И. , Денисенко П.Е. , Андреев В.Д. , Иванов А.А. , Сахабутдинов А.Ж. 
Published: February 2025

В статье приводятся результаты модельных и экспериментальных исследований радиофотонного модуля измерения доплеровского сдвига частоты и угла прихода эхосигналов в системах автономного вождения, который был представлен в первой части статьи [Вестник Поволжского государственного технологического университета. Сер.: Радиотехнические и инфокоммуникационные системы. 2022. № 3 (55). С. 58–71]. Обработка информации, полученной в радиофотонной части модуля, производится в программно-аппаратном анализаторе спектра путём сравнения частоты и фазы огибающих биений двух каналов, разделённых по поляризации, за малый период времени. Дополнительная информация о знаке доплеровского сдвига частоты и его значении при угле прихода 90° выделяется в анализаторе путём оценки полученных значений с учётом параметров опорного гетеродинного сигнала с заданной частотой и фазой. Показано, что целевые характеристики модуля, определённые в первой части статьи и заключающиеся в измерении доплеровского сдвига частоты в диапазоне ±100 кГц и диапазоне локационных частот 5–40 ГГц с погрешностью в ±10 Гц и измерении угла прихода в диапазоне от 0 до ±π/2 с погрешностью менее ±1,7 мрад, модельно и экспериментально достигнуты.

Introduction.Microwave measurements have found extensive application, particularly in radar systems, including those used in traffic control and automotive technologies. Typically, these measurements rely on electronic technologies. However, certain applications necessitate signals spanning a wide frequency range, from kHz to GHz, and implementing electronic approaches can be challenging due to various constraints. In contrast, photonic methods have gained significant attention in recent years due to their advantages, such as compact size, lightweight design, low insertion loss, immunity to electromagnetic interference, and the capability to process microwave signals over a wide band. In this document, we have presented and analyzed several radiophotonic methods for measuring various parameters of microwave signals, including instantaneous frequency, Doppler frequency shift (DFS), and angle of arrival (AOA). Among these parameters, DFS and AOA are particularly relevant as they can be used to track the speed and position of unmanned vehicles. All of the methods for measuring DFS and AOA that we have discussed are based on the Il’in-Morozov method and the tandem amplitude-phase modulation method, which are implemented using a serial cascade of amplitude and phase electro-optical single-port Mach-Zehnder modulators (TAPM) with carrier suppression. The aim of this article is to present and analyze the results of modeling and experimental studies into the radiophotonic module for measuring DFS and AOA of reflected signals in autonomous driving systems, which was presented in the first part of the article. Methodology and technique of the experiment. The tasks addressed in this article are related to the following requirements. In the developed system, transmitted, reflected, and heterodyne radio signals are inputted into two TAPMs, each of which defines one measurement channel with complete carrier suppression. As a result, the DFS (including the value and sign) and the AOA (orthogonal direction) can be obtained from the signal analysis of the two channels by analyzing the parameters of the envelope of their beat-notes. Processing of the received information in the radiophotonic part of the module is carried out using the software-hardware spectrum analyzer (SHSA), which we have specially developed for measuring these cases. The SHSA compares the frequency and phase of the beat envelopes of two channels separated by polarization over a short period of time. The operation of the SHSA is based on the principles of "frequency-amplitude" transformation measurement for DFS and the determination of the phase difference of the beat-note envelopes of two-frequency radiation from its information structure to obtain the value of the AOA, which is widely used in radiophotonic systems for various purposes. Findings.The expected characteristics of the module was defined in the first part of the article and include the DFS in the range of ±100 kHz and the range of location frequencies 5-40 GHz with an error of ±10 Hz. Additionally, it is expected to measure the UE in the range of 0 to π/2 with an error of less than ±1.7 mrad.