Alouette 1 Sweep-Frequency Sounder

The Alouette 1 Sweep-Frequency Sounder measured the ionospheric electron density in the altitude range 300 to 1000 km. The ionosonde was a radio transmitter that recorded the time delay between a transmitted and returned radio-frequency pulse. A continuum of frequencies between 0.5 and 12 MHz was sampled once every 18 s. Several virtual-range (delay-time) traces resulting from ground reflections, plasma resonances, birefringence of the ionosphere, nonvertical propagation, etc., were normally observed.

Alouette 1 扫频声纳在海拔300至1000公里的范围内测量了电离层电子密度。电离层探测器是一种无线电发射器，它记录了发射和返回的无线电频率脉冲之间的时间延迟。在0.5至12 MHz的连续频率范围内，每18秒采样一次。通常观察到由地面反射、等离子体共振、电离层的双折射、非垂直传播等因素产生的多个虚拟距离（延迟时间）轨迹。