Data block selection transmission method for radio frequency passive TDOA positioning system

Abstract

The invention discloses a data block selection transmission method for a radio frequency passive TDOA positioning system. The method comprises the steps: observation stations extract timing data blocks from an IQ data stream output by a radio frequency receiver and caches the timing data blocks into a queue; the observation stations evaluate the quality of the timing data blocks based on the carrier-to-noise ratio and the zero-crossing point number quality index, and report the timestamp and the quality index of each timing data block to a central station; the central station receives the observation station report, caches the observation station report into a queue, selects candidate data blocks from the report queue according to timestamps and quality parameters, and notifies the observation station to upload specified time data blocks; the observation stations receive a central station command, search data blocks at specified time from the cache timing data block queue and uploads the data blocks to the central station; and the central station receives the timing data blocks uploaded by the observation station and caches the timing data blocks to a timing data block queue to serve as input data of a TDOA estimation algorithm. The method is used for solving the problem of burst and bandwidth time-varying signal data block optimization and solving the problem of contradictionbetween network bandwidth and sampling rate.

Description

technical field [0001] The invention belongs to the field of wireless communication, and relates to a data block selection transmission method of a radio frequency passive TDOA positioning system. Background technique [0002] The radio frequency passive TDOA positioning system consists of a central station and 3 or more measuring stations, and the distance between the measuring stations is between several kilometers to hundreds of kilometers. The central station includes a data processing computer and application software, issues TDOA positioning tasks to the stations, receives signal IQ data blocks collected by multiple stations, estimates the TDOA between the stations, and calculates it according to the satellite positioning coordinates of the stations and the TDOA between the stations. Signal emission location. The measuring station is composed of radio frequency receiver, satellite positioning / timing module and computer. According to the task command of the central s...

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Problems solved by technology

[0007] 1) The measuring station transmits all collected IQ data to the central station: for example, the collection time stamp is 10ms, and the measuring station starts from every second, and encapsulates the signal sampling of each 10ms period in the whole second into a data block, and sequentially Passed to the central station; the advantage is that no sampling is discarded; the disadvantage is that the network bandwidth and central station computer performance requirements are high, and the sampling rate is limited by the transmission bandwidth, so it can only be used for ground fixed measuring stations, and the engineering cost is high; for vehicle-mounted Compared with the airborne measuring station, due to the limitation of communication link bandwidth and reliability, this solution is difficult to realize in engineering

[0008] 2) The measuring station periodically collects an IQ data segment and transmits it to the central station: for example, the collection time stamp is 500ms, and the measuring station starts from the whole second, collects a number of signal sampling points every 500ms and encapsulates them into data blocks, transmits them to the central station, and discards them Other sampling points; the advantage is that by adjusting the acquisition time scale and number of sampling points, it can adapt to various network transmission environments and sampling rates; the disadvantage is that when the measured signal is a short-term burst signal, such as walkie-talkie, transponder, radar and other signals, the station cannot guarantee that the extracted data segment contains a valid signal segment; when the instantaneous bandwidth of the measured signal has a time-varying nature, it cannot guarantee that the data block contains a signal segment with a wider instantaneous bandwidth

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