How are random walk and noise density IMU values obtained (ADIS16448)

[nousername1234500]

Hello,

In the file gazebo_imu_plugin.h, I am wondering how the below values were obtained from the ADIS16448 spec sheet.

static constexpr double kDefaultAdisGyroscopeNoiseDensity = 2.0 * 35.0 / 3600.0 / 180.0 * GZ_PI;
static constexpr double kDefaultAdisGyroscopeRandomWalk = 2.0 * 4.0 / 3600.0 / 180.0 * GZ_PI;
static constexpr double kDefaultAdisGyroscopeBiasCorrelationTime = 1.0e+3;
static constexpr double kDefaultAdisGyroscopeTurnOnBiasSigma = 0.5 / 180.0 * GZ_PI;
static constexpr double kDefaultAdisAccelerometerNoiseDensity = 2.0 * 2.0e-3;
static constexpr double kDefaultAdisAccelerometerRandomWalk = 2.0 * 3.0e-3;
static constexpr double kDefaultAdisAccelerometerBiasCorrelationTime = 300.0;
static constexpr double kDefaultAdisAccelerometerTurnOnBiasSigma = 20.0e-3 * 9.8;

From the spec sheet (https://www.analog.com/media/en/technical-documentation/data-sheets/adis16448.pdf), the below values are stated:
Angular Random Walk: 0.66 deg/sqrt(hr)
Gyro Noise Density: 0.0135 deg/sec/sqrt(Hz)
Velocity Random Walk: 0.11 m/sec/sqrt(hr)
Accel Noise Density: 0.23 mg/sqrt(Hz)

I understand that the units are different, but am not sure how the conversion is done between the two. Any help would be appreciated. Thanks!