Detection and measurement of hypersonic target radial velocity in pulse Doppler radar

В работе предложен алгоритм обнаружения и однозначного измерения радиальной скорости воздушных объектов (ВО), летящих с абсолютной скоростью, превышающей скорость звука в несколько раз (гиперзвуковых целей). Область применения алгоритма – импульсно-доплеровские РЛС с линейно-частотно модулированным (ЛЧМ) зондирующим сигналом (ЗС). Приведено описание, обоснование использования и результаты моделирования обработки пачки принятых радиоимпульсов разработанным алгоритмом на модели современной импульсно-доплеровской РЛС. An algorithm for the detection and unambiguous measurement of the radial velocity of supersonic air objects is proposed. The scope of the algorithm is pulse-Doppler radars with a linear frequency modulation (LFM). The description, justification of the use and the results of modeling the processing of a packet of received radio pulses by the developed algorithm on a model of a modern pulse-Doppler radar are presented.

Parametric profiler using a linearly frequency modulated signal.

At the Kotelnikov Institute of Radio Engineering and Electronics of RAS an experimental prototype of a parametric echo sounder-profiler with linear frequency modulation (LFM) of the sounding signal has been developed, manufactured and tested. Two chirp signals are emitted at frequencies of 144 kHz and 148 kHz. The difference reception frequencies have a frequency range of 1 kHz to 8 kHz. A wide band of differential frequencies is achieved by emitting two chirp signals. Laboratory and marine tests of the experimental model of the echo sounder-profiler have been carried out.

RSHL: a Ranging and Speed Measurement Method by Jointing Hyperbolic Frequency Modulation and Linear Frequency Modulation

In the waveform design, the distance measurement and resolution are a pair of irreconcilable contradictions. Linear Frequency Modulation (LFM) can alleviate this contradiction. LFM is widely used in radar and sonar, however, its Doppler tolerance is not ideal. Hyperbolic Frequency Modulation (HFM) signal has a particularly strong tolerance towards Doppler frequency shift. However, when the unidirectionally modulated HFM signal is in distance measurement, the Doppler delay of the matched filtering output cannot be eliminated, and there is a ranging error. After the echo signal of the combined HFM+LFM signal is matched filtering, the Doppler-induced delay is the same but opposite in direction, and the delay is closely related to the frequency, bandwidth, and pulse width of the transmitted signal. By using the combined signals, the ranging error in the ranging of single modulated HFM signal or LFM signal can be eliminated. In this paper, a Ranging and Speed measurement method by jointing Hyperbolic frequency modulation and Linear frequency modulation (RSHL) is proposed, which employs the same frequency band of positive and negative frequency modulation signals for speed measurement and ranging. In RSHL method, the signal parameters of the combined LFM+HFM signal can be set independently and no longer depend on each other. Therefore, the pulse width and frequency band in the combined LFM+HFM signal can be controlled independently, which can optimize the transmission signal form, reduce the operation cost, improve the measurement accuracy, and make full use of frequency band resources or pulse width resources.

LRS: A Positive and Negative Linear Frequency Modulation Method for Ranging and Speed Measurement

Linear Frequency Modulation (LFM) is widely used in radar and sonar scenarios. However, the Doppler tolerance of LFM signal is not ideal. When the unidirectionally modulated LFM signal is in distance measurement, the Doppler delay of the matched filter output cannot be eliminated, and thus there is a ranging error. After the positive and negative Frequency Modulation (FM) echo signals, which is based on the same frequency band, are matched and filtered, the delay caused by Doppler is the same and the direction is opposite. By using the inverse time delay difference of the positive and negative FM, speed can be measured, and the ranging error in the ranging of unidirectionally modulated LFM signal can also be eliminated. In this paper, based on the analysis of the influence of target moving speed on LFM signal ranging, a positive and negative Linear frequency modulation method for Ranging and Speed measurement (LRS) is proposed. Extensive simulation results show that the proposed LRS method can better estimate the distance and speed of moving targets, and it has reference value for engineering application.