Ultra low power receiver system

[hayatepilot]

Hello EEVblog Forum!

I have a problem with a receiver for a remote controlled crane hook wich we have given to commission to an external engineering firm. 
Since I'm a mechanical engineer with electronics as a side hobby I need some expert advice.

Use case of the receiver: the electronics need to control a small servo motor which triggers the release mechanism for the crane hook.
Most of the time it would be in standby and only need to wake up if a release command is received.
The main problem at the moment is that the first prototype needs way too much current. Over 5mA on average because the module needs to stay in receive mode pretty long (several 100 ms) to be able to receive the data. 
At least that is what the guy who developed the prototype says.
The target average current consumpion was 100uA. Is this even possible?

I know with wake-on-radio functionality (WOR) the RX would only need wo be active for a coulple of ms to check for a signal.
What components (rf module, microcontroller, etc) are ideal for such a system?
Has somebody done something similar already?
How is the WOR best set up?

I appreciate any advice you can give me.   

Greetings

[AG6QR]

How much latency is acceptable?

You can reduce the average current almost without limit by making the receiver sleep for a longer period of time between waking and checking for a signal.  The downside of long sleep periods is that the transmitter must transmit for a longer period of time to be certain the receiver will wake up, and there can be a long lag between transmitting a command and having the receiver wake up and receive it.

[hayatepilot]

The lower latency the better. 
But 2sec is the maximum.

At the moment there is a AMB2520 wireless module used in the prototype. The microprocessor is a EFM8 Sleepy Bee.
But at the moment the WOR function of the module is not used because the module can't wake up the micro. At least that is what the guy who developed it tells me. Apparently because the RF module only has SPI connection.
I need to know if he is right or if its BS. 

Greetings

[Marco]

Google for AMB2520, read handbook, look up WoR, don't immediately find anything relevant, look at pins (you are looking for a way to wake up the micro, so a pin going high or low is the logical way to do it) see there is a !DATA_INDICATE pin which goes low a settable amount of time before it starts outputting data ... so yes it's BS.