5.3 Operating Space of Radar Location and Radio Navigation Systems
107
Therefore, for I and II zones, which are primary for HNS, formula (5.66) becomes
a form:
σ r =
cσ τ
2 sin
1
2
sin
2
2
sin
1 + 2
2
sin
2 1
2
+ sin
2 2
2
.
(5.67)
At defining of operating zone boundaries of HNS it is necessary to plot an equal
accuracy curve according to (5.65), (5.66) or (5.67), in any point of which σ r = σ r tr .
For this, in cases of expression (5.66) or (5.67) result in more convenient form during
calculations:
σ r = K cσ τ
where K—tabular coefficient. Coefficient value is calculated by formulas, in case of
(5.67) the coefficient is calculated according to formula:
K =
sin
2 1
2
+ sin
2 2
2
2 sin
1
2
sin
2
2
sin
1 + 2
2
.
HNS equal accuracy curve is plotted on the base of the following relation:
K g =
σ r dr
(cσ τ )
.
For different values of K HNS, equal accuracy curves are depicted in Fig. 5.18.
As we can see from the above figure and given above formulas, the maximum
accuracy of object position finding is achieved on bases of the system. At given
σ r 1 and σ r 2 , an object position-finding accuracy worsens with offset from station
due to rise of calculation errors of position lines and angle α M reducing. Due to
low accuracy, HNS cannot be used for object position finding in directions, being
continuation of stations bases, for which bases angles are equal: 1 = 0
◦ or 360
◦ ,
either 2 = 0
◦ or 360
◦ , and in areas, where position lines are travel in a parallel way,
i.e., at α M = 0
◦ or 180
◦ .
To obtain an operating zone of HNS from an area (square), limited by a curve
equals to an accuracy, the segments are excluded in which signals receiving is not
provided by one or several stations of the system; i.e., such areas are excluded that
fall outside operational range of ground-based stations.
5.3.1 Radar Surveillance and Its Characteristics
The most modern radars have a directional pattern width comprised of units of
degrees. Since there is a requirement to radars to provide targets surveillance in
107
Therefore, for I and II zones, which are primary for HNS, formula (5.66) becomes
a form:
σ r =
cσ τ
2 sin
1
2
sin
2
2
sin
1 + 2
2
sin
2 1
2
+ sin
2 2
2
.
(5.67)
At defining of operating zone boundaries of HNS it is necessary to plot an equal
accuracy curve according to (5.65), (5.66) or (5.67), in any point of which σ r = σ r tr .
For this, in cases of expression (5.66) or (5.67) result in more convenient form during
calculations:
σ r = K cσ τ
where K—tabular coefficient. Coefficient value is calculated by formulas, in case of
(5.67) the coefficient is calculated according to formula:
K =
sin
2 1
2
+ sin
2 2
2
2 sin
1
2
sin
2
2
sin
1 + 2
2
.
HNS equal accuracy curve is plotted on the base of the following relation:
K g =
σ r dr
(cσ τ )
.
For different values of K HNS, equal accuracy curves are depicted in Fig. 5.18.
As we can see from the above figure and given above formulas, the maximum
accuracy of object position finding is achieved on bases of the system. At given
σ r 1 and σ r 2 , an object position-finding accuracy worsens with offset from station
due to rise of calculation errors of position lines and angle α M reducing. Due to
low accuracy, HNS cannot be used for object position finding in directions, being
continuation of stations bases, for which bases angles are equal: 1 = 0
◦ or 360
◦ ,
either 2 = 0
◦ or 360
◦ , and in areas, where position lines are travel in a parallel way,
i.e., at α M = 0
◦ or 180
◦ .
To obtain an operating zone of HNS from an area (square), limited by a curve
equals to an accuracy, the segments are excluded in which signals receiving is not
provided by one or several stations of the system; i.e., such areas are excluded that
fall outside operational range of ground-based stations.
5.3.1 Radar Surveillance and Its Characteristics
The most modern radars have a directional pattern width comprised of units of
degrees. Since there is a requirement to radars to provide targets surveillance in