Abstract: A radio receiver, configured to use an impulse UWB, includes: a reception antenna which receives the impulse UWB, a reception unit which amplifies the received impulse UWB and detects an envelope of the impulse UWB, maximum-peak and minimum-peak detection units which detect a maximum value and minimum value of the envelope, respectively, a comparator which acquires signal data from the envelope with an initial threshold value, a baseband unit which measures an error rate of the signal data, an MPU which calculates a correction value based on the error rate, and an arithmetic unit which calculates a corrected threshold value based on the maximum, minimum and correction values. The arithmetic unit transmits the corrected threshold value to the comparator. The comparator acquires the signal data from the envelope based on the corrected threshold value transmitted from the arithmetic unit.

Abstract: A radio receiver, configured to use an impulse UWB, includes: a reception antenna which receives the impulse UWB, a reception unit which amplifies the received impulse UWB and detects an envelope of the impulse UWB, maximum-peak and minimum-peak detection units which detect a maximum value and minimum value of the envelope, respectively, a comparator which acquires signal data from the envelope with an initial threshold value, a baseband unit which measures an error rate of the signal data, an MPU which calculates a correction value based on the error rate, and an arithmetic unit which calculates a corrected threshold value based on the maximum, minimum and correction values. The arithmetic unit transmits the corrected threshold value to the comparator. The comparator acquires the signal data from the envelope based on the corrected threshold value transmitted from the arithmetic unit.

Abstract: A planar antenna includes a patch conductor formed on a front surface of a dielectric substrate 20 so to be obliquely arranged in relation to an orthogonal axis of the dielectric substrate, the patch conductor having an elliptic shape; a microstrip line 40 for feeding power to a bottom part of the patch conductor; and a ground conductor plate 50 formed on a back surface of the dielectric substrate at a position thereof that is not overlapped with the patch conductor. By forming the patch conductor to be inclined only by ?, circular polarization characteristics in which axial ratio is 3 dB or less are given and the wideband such that the frequency bandwidth in which VSWR characteristics are 2 or less is 2 through 5 GHz and the wideband in UWB High band can be attained. The antenna characteristics in which any radiation directivity on the zenith direction does not depend on the frequency are obtained.

Abstract: It is an object of the present invention to provide a system with which 3-dimensional position can be accurately measured. Plural UWB transmitter-receivers (1), periodically transmitting PN codes of M system and preliminarily disposed on known positions are provided, a server (3) to synchronize the plural UWB transmitter-receivers (1) is provided, an RF tag (T), attached to a moving object (20) as to receive signals (I0) synchronously and periodically transmitted from the UWB transmitter-receivers (1) and reflect the signals (I0) adding inherent tag recognition signal, is provided, and the UWB transmitter-receiver (1) is composed as to obtain the distance to the moving object (20) attached with the RF tag (T) by synchronous summation and correlative calculation of the PN codes of M system reflected by the RF tag (T).