Other than computer vision, the most accurate positioning method is "ultra wideband" (UWB). It's possible to get close to cm accuracy, but it can be expensive. There is also a calibration problem: if the readers get bumped or moved, then you may have to recalibrate the system. UWB uses time distance of arrival instead of RF triangulation, so it's extremely accurate, and you can get to 100 Hz.

You can check out a few examples: http://pluslocation.com http://www.timedomain.com/ or google for: ultra wideband real time location

If you have specific questions I'd be happy to help - contact info is in my profile.

Why do you want to avoid computer vision ?

If the space is unobstructed and the objects are visually distinctive it should be fairly easy to do this with a pair of cameras with known position and orientation.

100 Hz is pretty fast but that's mostly a question of how much processing power you're able to throw at the problem.

I've done some work with 3D object tracking. If you'd like to discuss this further my contact info is in my profile.

Have you looked into wi-fi triangulation?

Here is one example:

https://www.navizon.com/product-navizon-indoor-triangulation...

If you went ultrasonic, this part can provide "0 to 765cm (0 to 25.1ft) with 1cm resolution" at 10 Hz

https://www.sparkfun.com/products/9495

If you have line of sight and can use fixed beacons whose position is known apriori, ultrasound is a good bet. However, if you need to track multiple objects within a defined space, things get tricky with ultrasound. Also, if 100hz is a strict requirement, ultrasound is not a great option due to issues such as signal attenuation in the environment.