Synchronous ranging system and synchronous ranging method

Abstract

The invention discloses a synchronous ranging system and a synchronous ranging method. The system comprises a main control computer, a digital signal processor (DSP), a digital to analog converter (D / A card), a detection signal emitting and receiving device and an analog to digital converter (A / D card). In all ranging periods in the whole ranging process of the ranging system and the method, the D / A card and the A / D card are in a continuous working state, adopt the same clock signal for ranging timing and have conversion frequencies satisfying an integer multiple relationship. The invention has the advantages that (1) the non-real-time property of an operating system of a host is more tolerable; (2) the influence of inconsistent frequency drift of single crystal oscillators is eliminated,and buffer data on the cards are unnecessarily managed in each measuring period so that the influence of the non-ideal equipment characteristics on the ranging accuracy is less.

Description

technical field [0001] The invention relates to the field of distance measurement for a target by using target echo signals, in particular to a distance measurement system and method for synchronizing by using target echo signals. Background technique [0002] In order to give an estimate of the target distance, the active sonar system needs to accurately calculate the time difference between the time when the active signal is transmitted and the time when the echo signal arrives. The traditional implementation method is: the digital / analog converter DA and the analog / digital converter AD are controlled by the host (such as a PC). In a detection period, when the active detection signal is ready to be launched, the DA card is turned on to make it work. Turn off the DA card after the active detection signal is transmitted; then start the AD card to start collecting data, and then turn off the AD card after the detection cycle is completed; in each detection cycle, the DA and A...

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Problems solved by technology

[0003] In this way of working, there are several factors that may cause man-made ranging errors: first, the Windows commonly used on PCs is not a real-time operating system, so the time measurement based on this system must be inaccurate; secondly, Due to the need to repeatedly enable and disable the DA and AD cards between different detection cycles, and manage the data queue in the buffer device on the card, this may lead to unstable work of the board hardware and introduce artificial ranging In addition, the input clocks of DA and AD cards in the sonar system are often independent of each other, and the frequency drift of independent clock sources is different. For signals with time-frequency coupling characteristics like chirp signals, it is will cause ranging error

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