current usage of Ultrasonic sensors

Hi all,
I have a customer that wants an vehicle ultrasonic interior sensor that has low standby current. The ultrasonic sensor I am currently using uses 10mA constantly when the system is armed.
Does anyone know of an ultrasonic sensor system that uses less current or even a system that goes into low power mode after a certain period of the vehicle being locked?

"10 ma would take about a year to run the battery down."

Hi Bobk,
This may be so but they have a fleet of cars. A number of new subsystems are to be installed. The total standby current of the new systems is around 16mA (if using my 10mA ultrasonics) the total current draw on the vehicle battery will therefore be about 32mA. This exceeds the customer requirements.

10mA already sounds pretty low for an active sensor; it has to fill the interior with ultrasonic waves, so it'll take some power to be effective. If it were to go into some kind of low power mode after a certain period, it would mean the sensitivity would have to be decreased, which is probably not what you'd want.

Probably would have to stick with a standard passive sensor setup if all you have left is 4mA to play with; or maybe they'd accept the higher draw if it were switchable, when they plan to leave the fleet parked in the garage for months at a time.