Method for improving distance measurement precision of responder

Abstract

The invention provides a method for improving distance measurement precision of a responder and aims to provide a simple and reliable method for improving downlink frame synchronization trailing edge pulse precision. According to the method, in a noncoherent mode, after an uplink signal is received by the responder, the uplink frame synchronization information is extracted after de-spreading, demodulation frame synchronization processing, an uplink frame synchronization signal is sampled by utilizing the downlink frame synchronization trailing edge pulse, the sampling value after re-framing is sent to a ground station through a downlink, and distance measurement is carried out by the ground station through calculating time delay between sending frame synchronization and receiving frame synchronization. The method for improving distance measurement precision of the responder is advantaged in that the compensation function is realized through programming in an FPGA chip of a responder hardware platform, a system clock of the responder is used as a modulation clock of the downlink, a 32-bit frequency control word accumulator DDS is utilized to generate a code sending clock, and the code sending clock is utilized to generate the downlink frame synchronization trailing edge pulse.

Description

technical field [0001] The invention relates to a realization method for improving the ranging accuracy of a transponder in a non-coherent mode. Background technique [0002] In the non-coherent mode of the current mainstream measurement and control system, the outer ballistic measurement system needs to obtain high-precision ranging data without a high-precision ranging transponder that works together. Realize high-precision ranging and positioning. In the ranging system, the errors introduced by the transponder mainly include the zero-value offset error of the transponder itself, the zero-value measurement error introduced by the measurement, and the zero-value variation error caused by the environmental state change. Transponder zero-value offset error and zero-value measurement error will be directly introduced into the system accuracy, but both can reduce the amount of errors introduced by these two factors by improving the transponder performance and measurement accur...

AI Technical Summary

Problems solved by technology

The implementation process is implemented inside the FPGA, the fractional part will be discarded, and the continuous accumulation of DDS will cause residual errors, resulting in errors in the generated code sending clock, which will eventually lead to inaccurate downlink frame synchronization trailing edge pulses

[0007] At present, there are mainly three methods to reduce the residual error: first, set the system clock to an integer multiple of the code sending clock. This method makes the clock design of the transponder very limited and basically impossible to realize; second, to increase the system clock, Taking this method will lead to problems such as reduced design reliability and increased power consumption; the third increase in frequency control word accumulator DDS digits, taking this method will lead to problems such as increased design resources, and the latter two methods will only produce the same The extension of the distance jump time does not fundamentally solve the problem

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