golang client distance from rssi and mhz

rssi.go

package rssi

import (
  "math"
)

const (
	// from wiki original formula: https://en.wikipedia.org/wiki/Free-space_path_loss
	fsplConstant = 27.55
)

// GetDistance function to get estimated distance from MHz and RSSI
func GetDistance(mhz, rssi float64) float64 {
	if mhz == 0 {
		mhz = 2412
	}
	return math.Pow(10, 1-20.0/fsplConstant*math.Log10(mhz)-rssi/fsplConstant)
}