The general exposure stems from the fact that the SACK option receiver can be made to do an arbitrary amount of work based on the reception of a single packet.
常见的安全漏洞源于这样一个事实：SACK 选项的接收方在收到一个包后可能会被要求做大量工作。
2
High dynamic environment may cause a large Doppler shift, thus the general GPS receiver is difficult to work reliably without outside assistance.
高动态环境会造成较大的多普勒频移，这使得一般的GPS接收机在没有外界辅助的情况下难以可靠工作。
3
Receivergeneral by the receiving circuit, amplifier, demodulator circuits, instruction decoder circuit, drive circuit and the implementation of the circuit composed of several parts.