The principle of direct sequence spread spectrum ranging is introduced and the echo model of near field ranging is discussed.

论述了直接序列扩频测距的原理，研究了近距离测距的回波模型。

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High frequency ground wave radar for near ocean inspection and ocean remote sensor is a method that use ocean echo wave Dopier spectrum to deduce the parameters of ocean situation.

高频地波雷达近海监测和海态遥感技术是一种利用海洋回波多普勒谱反演海态参数的方法。

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Strong echo produces outflow near the surface.

强回波区的降水会在近地面产生出流。

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"I don't really want to get involved in any big discussion about the situation, " he told the Sunderland Echo from the club's training camp near Antwerp in Belgium.

BBC: Reid desperate to spend

First presented on 11 March, 2002, and shown annually on 11 September ever since, the tribute consists of 88 7, 000-watt xenon light bulbs placed on a roof near the WTC site in two 48-foot squares that echo the shape and orientation of the twin towers.

BBC: 11 September history tour of New York

The street names of Spring Gardens (near Trafalgar Square) and Millbank (where the Abbey's mill once stood) echo Westminster's watery past.

BBC: The hidden history of Westminster