ROS Subscriber does not return correct value from the topic

Hi,

I've been using the Robotics Toolbox for a while now and I've never seen something like this before. It looks like a Matlab bug, but I don't know if I am doing something wrong.

In summary, I have a simulation running in gazebo that publishes to the topic: '/mavros/state' I created a simple subscriber as follows:

rosinit;
stateSub = rossubscriber('mavros/state');
msg = receive(stateSub)

The msg I received was the following:

    MessageType: 'mavros_msgs/State'
         Header: [1x1 Header]
      Connected: 1
          Armed: 0
         Guided: 0
           Mode: 'AUTO.RTL'

However, at the same time I was running the following command in a linux terminal:

rostopic echo /mavros/state

The echoed value in this terminal for the topic '/mavros/state' was the following:

header: 
seq: 1230
stamp: 
  secs: 1487749325
  nsecs: 495354524
frame_id: ''
connected: True
armed: True
guided: True
mode: AUTO.RTL

Note that there is a disparity between the value that I got in Matlab and the one I got in the terminal: Matlab says that the Armed and Guided properties are 0 (false), while the terminal says their values are 1 (true).

I know for a fact that the values expected from Armed and Guided are 1 (true), which means that the receive function is returning the wrong value for these properties.

Is this a Matlab bug? Any idea why this would be happening?

Observation: the message type for 'mavros/state' is of the type 'mavros_msgs/State', with the following definitions (obtained from running rosmsg info mavros_msgs/State in a matlab terminal):

std_msgs/Header Header
logical Connected
logical Armed
logical Guided
char Mode

Answer 1

[Marcelino Almeida]

I just updated my Matlab to R2016b (I had R2016a before) and the problem remains.

Running echo in matlab:

rostopic echo /mavros/state
Connected :  1
Armed     :  0
Guided    :  0
Mode      :  AUTO.LOITER
Header       
  Seq     :  3483
  FrameId :  
  Stamp      
    Sec  :  1487832172
    Nsec :  513096941

Running in a Linux terminal:

header: 
seq: 3483
stamp: 
  secs: 1487832172
  nsecs: 513096941
frame_id: ''
connected: True
armed: True
guided: True
mode: AUTO.LOITER

Again, all values are precisely equal in both, except for "Guided" and "Armed". I can't make much sense of this except accept that this is a Matlab bug.