3 ms·
I didn't see an explanation of what strapdown meant in this context, so I dug one up: "Traditional, stable-platform navigation systems commonly involve separat
by jcims 2y ago
I didn't see an explanation of what strapdown meant in this context, so I dug one up:
"Traditional, stable-platform navigation systems commonly involve separate accelerators and fibers or laser-based gyroscopes, with all the components mechanically and rigidly mounted on a stable platform that is isolated from the moving vehicle. This leads to the drawbacks of large size, poor reliability, and high cost. In contrast, in strapdown navigation systems, the inertial sensors are fastened directly to the vehicle’s body, which means the sensors rotate together with the vehicle. "
https://www.mdpi.com/2504-446X/8/11/652 https://www.mdpi.com/2504-446X/8/11/652
- plasticchris 2y agoOr in short, the sensors are strapped down to the platform being measured - like your phone’s sensors for example.
- boscillator 2y agoYes! It's in contrast to gimbaled systems. Putting the measuring instrument on a gimbal simplifies the math and often improves accuracy, but at the expense that you need this large moving object that needs more power.
- imglorp 2y agoGyros on gimbals have other drawbacks, such as drifting and gimbal lock.
- anothertroll456 2y agoJust gimbal lock. Drifting happens to all of them. But also the gimbal mechanisms, gimbal low response time, etc.
- UltraSane 2y agoThe ultimate example of this is the incredibly accurate and expensive and complicated floating Advanced Inertial Reference Sphere used on the Peacekeeper ICBM. https://en.wikipedia.org/wiki/Advanced_Inertial_Reference_Sphere https://en.wikipedia.org/wiki/Advanced_Inertial_Reference_Sp...
- sandworm101 2y agoExcept that a gimbaled system, if enclosed in a single box/pod, can also be described as a strapdown system. The term speaks more to separate modularity than how the system functions internally.
- kragen 2y agoI wonder if you could dangle the star tracker below the drone on a long string, decoupling its attitude from the attitude of the drone. A kevlar or spectra string capable of supporting 100 grams would be 20μm in diameter; 3 meters of it would weigh a milligram, which is significantly less than gimbals. A small weight a couple of meters below the star tracker on a carbon-fiber-composite rod would seem to be able to stabilize its attitude further except in yaw.