Get 4 position bound a position

Get 4 position bound a position
/**
     * @author phuc.duong
     * @todo G
     */
   public function getFourPosition($long, $lat, $distance) {
        $earthRadius = 6371;
        //latitude in radians
        $lat = ($lat * pi()) / 180;

        //longitude in radians
        $lon = ($long * pi()) / 180;

        //angular distance covered on earth's surface
        $d = floatval($distance) / $earthRadius;
        $arrTemp = array();
        $bearing = array(0, 90, 180, 270);
        foreach ($bearing as $key => $value) {
            $bearing = $value * pi() / 180; //rad
            $arrTemp[$key]['Lat'] = asin(sin($lat) * cos($d) + cos($lat) * sin($d) * cos($bearing));
            $arrTemp[$key]['Long'] = (($lon + atan2(sin($bearing) * sin($d) * cos($lat), cos($d) - sin($lat) * sin($arrTemp[$key]['Lat']))) * 180) / pi();
            $arrTemp[$key]['Lat'] = ($arrTemp[$key]['Lat'] * 180) / pi();
        }
        return $arrTemp;
    }