Method for estimating time delay of ground broadcast signals of digital television

Abstract

The invention discloses a method for estimating time delay of ground broadcast signals of a digital television, which belongs to the field of digital television broadcasting and wireless navigation positioning. The method comprises the following steps of: by using a transmitting time marker extracted from transmission code steams which are output from a digital television receiver through demodulation coding, reforming the transmission code streams into television signal frames which have same standard and same time sequence with transmitted signals, and then performing coding and modulation the same as those of a sending terminal in turn frame by frame; reforming a transmitted signal sample of a transmitting station which is nearest to a mobile receiving terminal; and performing cross-correlation operation on the sample and a stored received signal sample so as to accurately estimating the time delay for the broadcast signals transmitted by all single-frequency network transmitting station to reach a mobile terminal through different transmission paths. The method has high time delay estimation accuracy, is simple to implement, and has a low cost and a wide application range.

Description

technical field [0001] The invention relates to a method for estimating time delay of a digital TV terrestrial broadcast signal, belonging to the fields of digital TV broadcasting and radio navigation and positioning. Background technique [0002] 1. The main disadvantages of existing positioning systems [0003] Positioning technology has been widely used in various fields of the national economy, resulting in huge economic and social benefits. At present, the research hotspots at home and abroad are mostly limited to satellite positioning technology. For example: the Global Positioning System (GPS) of the United States, the Galileo system (Galileo) of Europe, the GLONASS system of Russia and the Beidou positioning system of my country. [0004] Take the most widely used GPS as an example. In order to improve the detection performance and secrecy ability of weak satellite signals, GPS adopts the spread spectrum technology of pseudo-random code, spreads the satellite navi...

AI Technical Summary

Problems solved by technology

[0006] 1) The positioning probability in the urban area is 60%, and it is almost impossible to complete the positioning indoors;

[0007] 2) Due to multipath effects, satellite orbit errors, ionospheric delay effects, etc., the positioning accuracy is affected;

[0008] 3) The real-time performance of positioning is poor, and it takes 30s or more to switch to the normal working mode during cold start

[0010] 1) The transmission power of the mobile phone signal is low, and the reception is greatly affected by noise interference and the location of the base station;

[0011] 2) There is an interception effect on the network;

[0012] 3) Users cannot directly obtain their own location information, but can only be completed through the central platform and multiple base stations, and the confidentiality of user locations is affected

[0022] 3. New problems brought by SFN

[0026] Although the SFN broadcast of digital TV or digital sound has greatly improved the coverage performance and reception effect, it has brought confusion in principle to the passive positioning based on the digital TV terrestrial broadcast signal: because the MS digital receiver tuned to a certain channel The received signals may come from several (for example, 3) BS transmitting antennas with completely different geographic locations, while the receiving antennas of current car radios and car TVs are omnidirectional, so if the MS uses this non-directional selection To receive SFN digital TV signals with no frequency difference, based on the existing principles and technologies, especially when the MS does not know its current exact location, it cannot correctly distinguish the same-frequency TOAs from different BSs.

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