US 10,520,598 B2 · Frame aware automatic gain control

Abstract

A method and apparatus for automatic gain control in a frame-aware pulsed ranging system is disclosed. A frame covers a period of time, and locationing pulses are emitted once per frame. The pulses are detected by a mobile unit with a microphone, which is able to trilaterate its physical position. To counteract false positives from reverberations of pulses emitted in prior frames, a noise threshold function declines over the course of the frame. As such, small amplitude locationing pulses received late in a frame are still detected because the small amplitude pulse exceeds the decayed noise threshold function. In this way, the noise threshold function is a filter that may detect high amplitude pulses early in a frame as well as small amplitude pulses late in a frame without detecting reverberation pulses early in a frame as false positives.

Claims20

Dependent claims

A method of locationing, the method comprising:

emitting, in a first frame period, a locationing pulse from a transmitter, the locationing pulse having a frequency;
receiving, at a detector, signals in a frequency band, the frequency band including the frequency of the locationing pulse;
determining a noise threshold function for the first frame period, the noise threshold function being a function of time during the first frame period and being based at least in part on a signal in the frequency band detected by the detector in a prior frame period, the prior frame period occurring before the first frame period;
and
detecting, in the first frame period, the locationing pulse at the detector if the locationing pulse satisfies a noise threshold condition, the noise threshold condition being based on the noise threshold function.

2 more elements

Dependencies are inferred from the claim text.

Frame aware automatic gain control

Life of this patent

Frame aware automatic gain control

Life of this patent

Abstract

Claims20