Chapter 4
Measuring Principles and Techniques
of Objects Movement Parameters
and Coordinates
4.1 Range Measurement Techniques
Range and angular coordinates measurements of objects are based on radio waves
rectilinear propagation in homogeneous medium, and uniformity of radio waves
propagation velocity equals to light speed c = 3 × 10
8 m/s.
Pulse range measurement method. The pulse method is used nowadays in the
most radar stations by measuring a distance to a target D according to elementary formula D =
ct D
2
, i.e., according to dwell time t D of reflected or reradiated
(retransmitted) pulse relatively to transmitted (sounding) pulse.
The functional scheme of pulse range measurement method and voltage oscillogram (surge) on its different points are performed in Fig. 4.1.
The radar synchronizer generates pulses providing simultaneous initiation of a
transmitter composed of a modulator and high-frequency generator (oscillator) and
dwell time meter. Oscillations form is determined by the radar modulator (2). These
are pulses of τ duration, following each other with T period. High-frequency generator “fills in” pulses of modulator with a carrier frequency (3). Pulsed high-frequency
oscillations are formed by a transmitting antenna into indirect (sky) beam. When a
target gets into this beam, it scatters an incident on it radio waves in all directions
including in direction to the radar. Picked up by receiving antenna, a weak reflected
signal (4) is amplified and detected (5) by radar receiver. In the most pulse radars, the
detection is carried out regardless of phase of high-frequency fill-in. In other words,
high-frequency fill-in is used only as a carrier frequency, and contained in it information on a target is often not used. We should also mention that up-to-date pulse
radars are usually represent a single-antenna radars, meaning that transmitting and
receiving antennas are joined, and antenna switching from transmitting mode into
receiving one and vice versa is provided by fast-response device called polyplexer
or antenna switch. The pulse, after being reflected from a target (target pulse), goes
from receiver output to meter forcing at this moment to conduct dwell time reckoning
t D of reflected pulse relatively to sounding pulse. Dwell time meter t D for reading
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021
D. A. Akmaykin et al., Theoretical Foundations of Radar Location
and Radio Navigation, Springer Aerospace Technology,
https://doi.org/10.1007/978-981-33-6514-8_4
55
Measuring Principles and Techniques
of Objects Movement Parameters
and Coordinates
4.1 Range Measurement Techniques
Range and angular coordinates measurements of objects are based on radio waves
rectilinear propagation in homogeneous medium, and uniformity of radio waves
propagation velocity equals to light speed c = 3 × 10
8 m/s.
Pulse range measurement method. The pulse method is used nowadays in the
most radar stations by measuring a distance to a target D according to elementary formula D =
ct D
2
, i.e., according to dwell time t D of reflected or reradiated
(retransmitted) pulse relatively to transmitted (sounding) pulse.
The functional scheme of pulse range measurement method and voltage oscillogram (surge) on its different points are performed in Fig. 4.1.
The radar synchronizer generates pulses providing simultaneous initiation of a
transmitter composed of a modulator and high-frequency generator (oscillator) and
dwell time meter. Oscillations form is determined by the radar modulator (2). These
are pulses of τ duration, following each other with T period. High-frequency generator “fills in” pulses of modulator with a carrier frequency (3). Pulsed high-frequency
oscillations are formed by a transmitting antenna into indirect (sky) beam. When a
target gets into this beam, it scatters an incident on it radio waves in all directions
including in direction to the radar. Picked up by receiving antenna, a weak reflected
signal (4) is amplified and detected (5) by radar receiver. In the most pulse radars, the
detection is carried out regardless of phase of high-frequency fill-in. In other words,
high-frequency fill-in is used only as a carrier frequency, and contained in it information on a target is often not used. We should also mention that up-to-date pulse
radars are usually represent a single-antenna radars, meaning that transmitting and
receiving antennas are joined, and antenna switching from transmitting mode into
receiving one and vice versa is provided by fast-response device called polyplexer
or antenna switch. The pulse, after being reflected from a target (target pulse), goes
from receiver output to meter forcing at this moment to conduct dwell time reckoning
t D of reflected pulse relatively to sounding pulse. Dwell time meter t D for reading
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021
D. A. Akmaykin et al., Theoretical Foundations of Radar Location
and Radio Navigation, Springer Aerospace Technology,
https://doi.org/10.1007/978-981-33-6514-8_4
55