Ilmsens HAL API  1.1.1
A cross-platform C-library for interfacing m:explore UWB-sensors
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Measurement Data Format

This section briefly explains the format and buffer layout for measured data returned by the HAL API.

More detailed information can be found in the HAL API Programming Guide.

Data format of raw measured data

The data retrieved from the sensors is returned as 32 bit integers (int) to avoid any loss of precision while keeping the amount of data as small as possible. Besides the actual signal samples, additional status information is contained in the output buffer. How to convert raw integers into physical units is explained in detail in the HAL API Programming Guide.

Calculating the output-buffer size

This section describes how to calculate the minimum size of the output buffer for retrieving measured data for a given sensor configuration.

  • In case of sensors with different configurations included in the measurement run

    \begin{eqnarray*} BufferSize_{min} &=& \sum_{i} ChannelSize(i) \times NumberOfRx(i) \\ &=& \sum_{i} 2^{MLBS-order(i)} \times NumberOfOversampling(i) \times NumberOfRx(i) \end{eqnarray*}

  • In case of common configuration for all sensors included in the measurement run

    \begin{eqnarray*} BufferSize_{min} &=& NumberOfSensors \times ChannelSize \times NumberOfRx \\ &=& NumberOfSensors \times 2^{MLBS-order} \times NumberOfOversampling \times NumberOfRx \end{eqnarray*}

Layout example of output buffer

The following layout assumes a measurement with two indentically configures 9th order m:explore sensors.

data_format.png
Buffer layout of example setup with two measuring 9th order m:explore sensors