A smarter helicopter is semi autonomous so can maintain stable flight on its own. It is aided by a computer and sensors that determine when it is level and what direction it is going, as well as operating servos, which control the flight by mechanically moving appropriate parts. Commands are sent by radio, symbols meaning go up, down, left right, fast, slow etc. The inbuilt computer works out what to do, considering the current flight and the new command.
The type with a joystick might be semi-smart, as there is usually still some inbuilt stabilization to make it easier to fly. The commands are sent by radio too. This system is more like radio controlled model planes and cars. The operator uses the flight controls more or less like a pilot. These commands directly or indirectly control the individual servos that control flight. Generally these operate by receiving a pulse of a certain width representing the required position for the servo arm, that is repeated periodically.
The pulses for a number of servos are sent sequentially then repeated, with the width of individual pulses changing according to the operator's inputs. The transmitter unit (remote) assembles the pulses for the various controls like switches and throttle and joystick into a series of pulses in a fixed order (time sequence) This stream of pulses repeats regularly and is used to modulate the radio transmitter.
The receiver first demodulates the radio signal to obtain a replica of the stream of pulses as was provided at the transmitter. It further disassembles the series of pulses into signals for each control, so that the first pulse in the sequence is for servo one, the second is for servo 2 etc. Look up RC servo and radio control for more info. There are a few different types of radio used, but the servos all use the same scheme.
The radio control (RC) servo is a position servo. It uses a feedback control system internally to drive a motor that positions the actuator arm at an angle proportional to the pulse width, and holds that position. The mechanical output is an arm or cross arm that rotates through an angle like 90 degrees. Typically, with 1ms pulses the arm is at one end, with 1.5ms pulses the arm rotates to the middle position, and with 2ms pulses the arm is at the other end. These different control functions are known as channels, so there are proportional channels and simpler on/off channels. Other servos control motor speeds for rotors etc. in a similar way.
http://en.wikipedia.org/wiki/Servo_%28ra...
Some model helicopter types use a similar flight mechanism to full size helicopters. Others are very simple types using two rotors rotating in opposite directions, which eliminates much of the mechanical complexity. These are not like full size helicopters.
The site link (below) has some good information. When you turn it on, it will start transmitting the base signal (according to the link, it seems like there are multiple channel frequencies to control the many different actuators on the helicopter). The signal is changed, based on the position of the control stick. It's probably by frequency shift; I didn't find a definite on this.
On the helicopter, the receiver interprets the signal and the change in signal to move actuators which move other parts controlling blade pitch and speed for example.
Here's another interesting link. It is a PDF.
http://dasl.mem.drexel.edu/tutorials/fil...
Please understand that you question is very funny. There are so many very complicated things involved, who knows what you are asking? How much aerodynamics do you understand? How much electronics do you understand? Physics and math? Sometimes people who ask such questions just want a superficial statement of the obvious like you get on TV documentaries. So the best answer will come from someone who knows just a bit more than you do. If you spend 4+ years of college in math, science or engineering, you will understand most of it.
The remote sends signals to NASA, and then NASA flashes a signal from one of their satellites to the helicopter, and the helicopter has to decipher those signals, which may or may not cause it to move.
How does it work? You control it with the remote and it flys where you make it go.
helicopter
