Coherent simulation method for radar echo Doppler frequency based on real-time frequency measurement

A technology of Doppler frequency and radar echo, which is applied in the coherent simulation of radar echo and Doppler frequency coherent simulation of radar echo based on real-time frequency measurement, can solve the problem of limited frequency discrimination range of phase-locked loop and phase-locked Loop phase-locked tracking is difficult, and it is difficult to accurately generate the simulator regeneration frequency reference, etc., to achieve the effect of improving flexibility and wide adaptability

Active Publication Date: 2017-10-20
BEIJING INSTITUTE OF TECHNOLOGYGY
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method eliminates pseudo-Doppler, but the frequency discrimination range of the phase-locked loop is limited. For the large-bandwidth signal generated by the radar, the phase-locked loop phase-locked tracking is difficult, and it is difficult to accurately generate a simulator regeneration frequency reference that is coherent with the radar reference frequency. As a result, it is difficult to use the phase-locked regeneration method to realize the Doppler frequency coherent simulation of the radar echo

Method used

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  • Coherent simulation method for radar echo Doppler frequency based on real-time frequency measurement
  • Coherent simulation method for radar echo Doppler frequency based on real-time frequency measurement
  • Coherent simulation method for radar echo Doppler frequency based on real-time frequency measurement

Examples

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example 1

[0030] This example is based on the radar echo Doppler frequency coherent simulation method based on real-time frequency measurement. In this example, the radar transmit signal is a chirp signal. The specific process is as follows:

[0031] Step 1: The simulator receives the signal model

[0032] The simulator receives the pulse-modulated chirp signal transmitted by the radar, expressed as follows:

[0033]

[0034] Among them, f 0 is the radar transmitting carrier frequency, T p is the pulse width, T r is the pulse repetition period, A is the amplitude of the chirp signal, and K is the modulation coefficient of the chirp B is the chirp bandwidth, is the initial phase of the radar transmitting carrier, Rect(t) is a rectangular pulse function, defined as follows:

[0035]

[0036] Step 2: Doppler frequency coherent simulation

[0037] The simulator uses a frequency of f Lo_sim The local oscillator down-converts the received signal, then performs low-pass filterin...

example 2

[0091] This example is based on the radar echo Doppler frequency coherent simulation method based on real-time frequency measurement. In this example, the radar transmit signal is a linear frequency modulation signal, and the nominal frequency of the working clock of the radar and the simulator is 300MHz, namely f' clk_radar =f' clk_sim = 300MHz, The quasi-stability of the radar clock is 10ppm, that is, the actual frequency of the radar working clock f clk_radar =300×(1+10 -5 ) MHz; the quasi-stability of the simulator clock is -10ppm, that is, the actual frequency of the simulator working clock f clk_sim =300×(1-10 -5 )MHz, considering the radar working clock count N 1 = 750000 clock cycles, resulting in period The specific process of this method is:

[0092] Step 1: Simulator receives signal model description

[0093] The chirp transmit signal received by the simulator is expressed as follows:

[0094]

[0095] In the formula, T P =0.5×(1-10 -5 )ms is the widt...

example 2

[0135] Doppler frequency simulation accuracy analysis for example 2

[0136] The simulator uses DDS technology to generate the local quadrature Doppler signal cos(2πf' d n s ) and sin(2πf' d n s ), where the Doppler frequency control word is:

[0137]

[0138] Among them, M 1 =40 is the word length of the phase accumulator in the simulator DDS.

[0139] Then the actual Doppler frequency value of the radar echo generated by simulator simulation is:

[0140]

[0141] After the simulated echo is received, detected and measured by the radar without distortion, the Doppler frequency radar tracking frequency word is obtained as:

[0142]

[0143] Among them, M 2 =40 is the word length of the radar tracking loop DDS phase accumulator.

[0144] Solving the radar tracking frequency word into a Doppler frequency measurement yields:

[0145]

[0146] From this, it can be obtained that the Doppler frequency f after radar calculation dr with the desired Doppler freque...

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Abstract

The invention provides a coherent simulation method for a radar echo Doppler frequency based on real-time frequency measurement. The specific process comprises the steps that step one, a simulator performs envelop extraction on transmitting signal pulses of a radar, and the simulator performs clock counting N3 by using a local clock in N2 radar transmitting pulse periods; step two, a corrected Doppler frequency simulation variable f'd is calculated, wherein f'd=fd*(N1N2/N3)*(1/[alpha]), fd represents the Doppler frequency corresponding to a simulated target, alpha represents a nominal frequency ratio of working clocks of the radar and the simulator, and N1N2/N3 is a frequency correction coefficient; and step three, coherent simulation for the radar echo Doppler frequency is realized by using the Doppler frequency simulation variable f'd. Coherent simulation for the radar echo Doppler frequency can be realized quickly according to the method.

Description

technical field [0001] The invention relates to a radar echo coherent simulation method, in particular to a radar echo Doppler frequency coherent simulation method based on frequency real-time measurement, and belongs to the technical field of radar echo simulation. Background technique [0002] Radar echo simulation is the product of the combination of system simulation technology and radar technology. The object of radar echo simulation is the radar target and environment. The simulation result is to reproduce the radar echo signal containing radar target and target environment information. The Doppler frequency of the radar echo directly reflects the relative velocity information between the radar and the target. However, when the radar echo simulator (hereinafter referred to as the simulator) and the radar system reference clock have different sources, the local clock of the simulator is used to directly simulate There is inevitably a frequency deviation between the gene...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01S7/40
CPCG01S7/4052
Inventor 崔嵬沈清侯建刚刘芳政向锦志吴嗣亮
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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