Positional information transmitter, communication terminal, and positioning system

Abstract

The invention provides a positional information transmitter, communication terminal, and positioning system. A positioning system for acquiring current positions outside and inside buildings, wherein the problems of the null points and / or signal interferences of a positional information transmitter located inside a building can be solved, thereby preventing the positioning errors from becoming large, while preventing the positioning time from increasing. A positional information transmitter (2) comprises a plurality of mutually spaced antennas (28) and a radio transmitting unit for repetitively transmitting, via the antennas, a positional information signal that is a radio signal having a compatibility with a satellite positioning signal transmitted from an artificial satellite and including a positional data indicating a particular position. The radio transmitting unit transmits the positional information signals, which include the same positional data, via the respective antennas (28) in parallel by use of mutually different channels or alternatively in a time division manner by use of any given channel.

Description

technical field [0001] The present invention relates to a position information transmitter, a communication terminal, and a positioning system, and particularly relates to a technique for obtaining the current position of a communication terminal indoors, etc., where radio waves from artificial satellites cannot be captured. Background technique [0002] As a system for measuring positioning using wireless signals (hereinafter referred to as "satellite positioning signals") transmitted from artificial satellites such as GPS (Global Positioning System) satellites, if a communication terminal such as a GPS receiver enters a room or In areas such as underground streets that cannot receive satellite positioning signals, the positioning accuracy will decrease, or the positioning cannot be measured. [0003] As a solution to this, for example, Patent Document 1 discloses a technology in which a frequency (for example, a center frequency of 1.57542 GHz) and a frequency used in GPS ...

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Problems solved by technology

In addition, in reality, the invalid point is reflected by various objects, and its position or width changes, and the signal strength may increase under the influence of reflected waves.

[0014] In this way, there is a problem in the prior art that under the influence of an invalid point, although there is a nearer position information transmitter, a signal from a far position information transmitter is received, and a positioning error becomes large

[0015] In addition, in the case where location information transmitters are installed at high density (for example, 5m intervals) in order to improve positioning accuracy, there is a problem that the nearest location information transmitter and other location information transmissions using the same PRN number occur. Interference of signals between machines, unable to receive position information signals from the nearest position information transmitter

If the number of PRN numbers is large enough, different PRN numbers can be assigned to each location information transmitter, but according to Non-Patent Document 1, the number of PRN numbers that can be used indoors is limited to about 10 in terms of specifications, so in reality This method is difficult to implement in

[0016] Furthermore, there is a problem that the position information signal cannot be captured near invalid points or at places where signal interference occurs, or even if it can be captured, the position information cannot be acquired due to a high bit error rate, and the positioning time increases.

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