Why do large vehicles like trucks and buses often have significant and unstable discrepancies between their inferred orientation and their actual orientation?

[HULoaf]

Why do large vehicles like trucks and buses often have significant and unstable discrepancies between their inferred orientation and their actual orientation? Could you please share possible reasons and solutions? Thank you!
为什么像卡车，巴士之类的大车推理出来的目标朝向与实际偏差很大且不稳定，能否告知我可能的原因及解决方案，感谢