JPH011982A - Direction measuring device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an azimuth measuring device, and relates to a direction measuring device.
ctical Air Navigation System
stem) system, it relates to an azimuth measuring device that measures the benevolence of an aircraft with respect to a ground station.

[Conventional technology]

Generally, direction measurement in a TACAN device is performed as follows. The TACAN ground equipment transmits an average of 2700 ppS (Pulse Pa) per second through a directional antenna that rotates at a rate of 15 times per second.
A random pulse signal for distance measurement (1r per 5 seconds) or a constant station identification pulse signal of 2700 pps is sent out once every 37.5 seconds. Along with this, when the directivity of this antenna points to a certain reference direction,
As an azimuth reference pulse signal that can be distinguished from the random pulse signal, a main reference pulse is used as a reference azimuth signal, and a sub reference pulse signal is transmitted eight times per rotation of the antenna.

When this is received by the onboard TACAN device located in a fixed direction with respect to the TACAN ground device, the received pulse signal changes to a fundamental frequency of 15 as the directivity of the antenna of the ground device rotates.
Hz and is received as a pulse modulated in amplitude by an envelope of 135) 1 z.

If the phase (θ1) of the fundamental wave (15 Hz) component of the envelope of the received amplitude modulated pulse is measured with reference to the time point when the azimuth main reference pulse signal is signaled, this will allow the aircraft's azimuth angle to be determined as the main reference. It is determined as the rACAN azimuth angle from the azimuth in the range of 0 to 360 degrees. To my colleague, the phase of the 135Hz component of the deformed pulse envelope (θl)
If measured with reference to the time of reception of the M azimuth sub-reference pulse signal, the range of electrical angles from 0 to 360 degrees is T A C N
The fine azimuth angle is determined in the range of 0 degrees to 40 degrees. '11'
To determine the ACAN azimuth (θ), 'f' A
The CAN coarse azimuth (θl) is used to divide the bearing into 40 degree sectors, and the TACAN fine azimuth is used to determine the exact bearing within the 40 degree sector. This relationship is expressed by a formula S: 40 degree sector determination a(
i (round down to the nearest whole number) θ=8x4Q (degrees) 109' ・・・・・・・・・
... (2) The fiTACAN azimuth can be found using (2).

[Problem that the invention seeks to solve]

In the conventional radio navigation device such as the TACAN system described above, the phase relationship between the 15 Hz amplitude modulation signal and the 135 Hz amplitude modulation signal is shifted due to the disturbance of the spatial radio waves and the randomness of the received pulse amplitude modulation. Sometimes.

In such a case, TAC is
When measuring the AN direction, near the boundary of the 40 degree sector, etc.
There is a drawback that an erroneous measurement (40 degree error) of the azimuth angle (θ) occurs due to the apparent error in the S determination. For example, if the azimuth angle is 79 degrees (near the 40 degree sector boundary), and assuming that the coarse azimuth angle (θl) is found as 82 degrees and the fine azimuth angle (θ) is found as 39 degrees, then the +
1) Substituting this value into equations (2) yields the azimuth angle (θ)
is determined as 119 degrees, which has the disadvantage that it is determined as a value including the above-mentioned 40 degree error, which is 40 degrees off from the actual (true) azimuth angle of 79 degrees.

The purpose of the present invention is to eliminate the above-mentioned drawbacks and to solve the problems caused by disturbance of spatial radio waves and randomness of pulse amplitude modulation.
It is an object of the present invention to provide an azimuth measuring device in which a stable azimuth output can be obtained without causing a 40-degree deviation up to a phase shift between 35 Hz amplitude modulated signals of ±19.9 degrees, which is approximately 1/2 of the sector occupation angle.

[Means for solving problems]

The device of the present invention is mounted on a mobile object such as an aircraft, and transmits a coarse azimuth signal in a 360-degree range transmitted from a fixed station on the ground, its reference azimuth signal, and each sector obtained by equally dividing the reference 360 degrees into N115. The direction measuring device d measures the direction of the mobile object relative to the fixed station while receiving a fine direction signal to be set, comprising direction signal extraction means for extracting the coarse direction signal and the fine direction signal independently of each other; While receiving the coarse azimuth signal and the treetop azimuth No. 1M extracted by the signal extracting means, the phase shift between these two azimuth signals is corrected within a range of 1/2 or less of the occupation angle of the sector, and the signal is directed to the fixed station. and azimuth calculation means for calculating the azimuth.

〔Example〕

Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention.

The block diagram shown in FIG. 1 shows a pulse demodulator 1. Sample hold/filter 2. Reference direction pulse detector 3. A-
D converter 41 Equal interval time counter 5° 5in-Cos generator 6. Coarse direction (θl) calculator 7. It is configured with a fine direction (09') calculator 8 and a direction calculator 9, and among these components, the direction calculation field 9 is the direction calculation means, and the others calculate the coarse direction signal and the fine direction signal independently of each other. A direction signal extracting means is formed.

The signal received by the antenna from the TACAN ground station is amplified by the onboard receiver, converted into a band F wave, and then supplied to the pulse demodulator 1, where it is demodulated and converted into a pulse at the baseband. converted. This pulse is supplied to a sample hold/filter 2 and a reference azimuth pulse signal detector 3. The sample hold/filter 2 holds the peak level of each supplied base pad/do pulse, smooths it to remove unnecessary harmonic components contained therein, and then supplies it to the A/D converter 4. The A/D converter 4 converts the peak level of the pulse into a digital quantity using the regularly spaced sample signal received from the equally spaced time counter 5.

The reference azimuth pulse signal detector 3 detects the reference azimuth pulse signal included in the input base punt pulse, and
A reference direction pulse signal is generated at every 14z detection time,
This is supplied to the equal interval time counter 5. The equal interval time counter 5 counts a clock of a constant period and outputs a sample signal of a constant interval.
In addition, the equidistant time counter 5 is reset to 01 and restarted each time it receives the reference azimuth pulse signal. S in -
The Cos generator J6 generates 5 inches (2r/li) and Co5 (2π/li) of the sample signal tiO value at the constant interval in the same cycle in synchronization with the reference azimuth pulse signal. However, f is the frequency of the reference direction signal. This digital fisin (2π/li) and Cos (
:)r/li) is supplied to a coarse orientation (al) calculator 8. Further, from the A-D converter 4, the pulse amplitude +19
A digital signal a1 of Wi is supplied to a coarse azimuth (θK) calculator 7. The azimuth calculator 7 has digital quantities al and 5i
Multiply by n(2π/li) to obtain digital 1a18in
(2π/li) is obtained and cumulatively added. Similarly,
The digital quantity cO5 (2π/li) is multiplied by ai, and the digital quantity Co51 (2π/li) is cumulatively added.

These cumulative additions include ai8in (2π/li) and alCos (2π
/li), these digital i are set as X and Y, and at the end of each fixed time interval, the rough azimuth calculation (θ凰) is performed based on the following formula, and the rough azimuth angle (al) is divided into 2. ,
The signal is supplied to the true direction calculation circuit 9.

When IXI≦IYI, θ1:jan-” li) and Co5 (18π/li). These digital quantities 5in (18π/li) and Cos (18π high) are supplied to the precision azimuth calculator 8 along with al from the A-D converter 4. The fine azimuth (θ*') IK-small device 8 performs the same calculation process as the coarse azimuth (al) calculator (θ1), and calculates the fine azimuth (09') at the end of each fixed time interval. ) and is supplied to the true direction calculation circuit 9.

The angles θ1 . θ1 corresponds to the deviation angle from the reference azimuth signal.

Next, a method for calculating the Takan azimuth (θ) will be described. As shown in FIG. 2, the azimuth calculator 9 includes a 40 degree sector (8) detector 101 multiplier 11. Subtractors 12, 13,
15, adder 14.18, determiner 16, and selector 1
Consists of 7.

The 40 degree sector (8) detector 10 determines a sector value S (integer) according to the value of the rough azimuth angle θl. S is θ supervisor = 0
It is a value obtained by dividing ~360 degrees into 40 degree sectors, and is 0, 1, etc. depending on the value of θ1. ..., 8.

The multiplier 11 multiplies the value of S by 40 degrees to obtain the boundary angle θa of the 40 degree sector, which is supplied to the subtractors 512 and 15, the adder 14, and the selector 17. The subtractor 12 calculates the deviation angle θb between the rough azimuth angle θl and the boundary angle θa of the 40 degree sector.
is calculated and supplied to the subtracter 13.

The subtracter 13 calculates the deviation angle θC between the θb and the fine azimuth angle θ,′.
is determined and supplied to the determiner 16. The determiner 16 determines the θC
is less than 1α1, greater than or equal to −α, or greater than or equal to +α, and judgment signals 19.20. Alternatively, 21 supplies the selector 17. The selector 17 is
The output data of the multiplier 11, the output data of the subtracter 15, or the output data of the adder 14 corresponding to the determination signal are selected, and one of the three data is supplied to the adder 18. The adder 14 adds 40 degrees to the output data (SX40 degrees) value of the multiplier 11 and outputs the result. A subtracter 15 subtracts 40 degrees from the output data (SXJQ degree) value of the multiplier 11, outputs the value, and supplies the resulting value to the selector 17, respectively.

The adder 18 adds the fine azimuth angle 09' and selected data of one of the three data supplied from the selector 17 to obtain the vertical azimuth θ. In this embodiment, α is set to 20 degrees.

Now, here, the rough azimuth angle θ! is 82 degrees, and the fine azimuth angle θ9' is 39.8 degrees.
I'll try to find it.

That is, since S=2, the above θb is θb2θl−
8X40 (degrees) = 82-80 (degrees) = 2 (degrees) Also, the above θ. is θ0 = θb-θ, t = 2-39.8 (degrees) = -37.8 (degrees) The output data P of the selector 17 is P = sx4o-40 (degrees) = 40 (degrees) Therefore, Takan azimuth θ is determined as θ2θ, '+P = 39.8+40 (degrees) = 79.3 (degrees).

Also, the fine azimuth angle θ1 is 79.8 degrees, and the fine azimuth angle 09' is 0.
．． Assuming 2 degrees, θb = θl 5x40 (degrees) = 79.8-40 (crime = 39.g (degrees) θ0 = θb-θ, 1 = 39.3-0.2 (degrees) = 39.6 (degrees) At this time, the output data P of the selector 17 is P = SX40 + 40 (degrees) = 80 (degrees) Therefore, the Takan azimuth θ is θ = 09'0P = 0.2 + 80 (degrees) = 80. 2 (degrees).

Next, the coarse azimuth angle θ1 is 79.8 degrees, and the fine azimuth angle 09' is 39 degrees.
．． In the case of 8 degrees, θb = θ Summer - 8X40 (degrees) Near 9, 8 - 40 (degrees) = 39.8 (degrees) θ0 = θb - θ, l = 39.8 - 39.8 (degrees) = 0 (degrees), the output data P of the selector 17 at this time is P=
40 (degrees) Therefore, the Takan direction θ is obtained as θ=θ, '+P = 39.8+40 (degrees) = 79.8 (degrees).

The embodiments described above are particularly suitable for modern digital signal processing systems, and are suitable for microprocessors, ROMs, and RAMs.
By using AM or the like, the hardware is also simplified and can be easily realized.

Also, although this example is an example implemented in a TACAN device,
It is clear that it can easily be implemented in other devices with comparable performance to the TACAN device.

〔Effect of the invention〕

As explained above, the present invention extracts the coarse azimuth signal and the fine azimuth signal independently from each other in the frequency domain, and also eliminates the phase shift between the two signals within a range of a maximum of 1/2 of the sector occupancy angle. By providing a means for correcting, 15
The effect is that a stable azimuth output can be obtained even when the phase relationship between the Hz amplitude modulation and 135Hz amplitude modulation signals is received with a maximum sector occupancy angle of 172 degrees or less, or up to ±19.9 degrees in the case of TACAN equipment. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is a block diagram of an embodiment of the present invention.
FIG. 3 is a plot diagram showing in detail the direction calculation axis Z in the figure. 1.°...° Pulse return'FAD, 2...Sample hold 7 filter, 3...Reference direction pulse detector, 4. Group A-D converter, 5. ...Evenly spaced time counter, 6...Sin * Cos
Generator, 7... Coarse direction ('t) n Usufruct, 8.
...Precise direction (01') calculator, 9 ...Direction calculation contribution 1.10 ...40 degree sector (S) detector, 11 ...Multiply Vessel, 12, 13, 15...
...Subtractor, 14.18・Old...Adder, 16...
... Judgment circuit, selector for 17.... Agent Patent Attorney Susumu Uchihara

Claims (1)

[Claims] A coarse azimuth signal with a range of 360 degrees transmitted from a fixed station on the ground mounted on a mobile object such as an aircraft, its reference azimuth signal, and the reference azimuth signal are common, and 360 degrees is equal to N pieces. In an azimuth measuring device that measures the azimuth of the mobile object relative to the fixed station while receiving a fine azimuth signal set for each divided sector, azimuth signal extraction extracts the coarse azimuth signal and the fine azimuth signal independently of each other. means, and receiving the coarse azimuth signal and fine azimuth signal extracted by the azimuth signal extraction means, and correcting the phase shift between these two azimuth signals within a range of 1/2 or less of the occupation angle of the sector. An azimuth measuring device comprising azimuth calculation means for calculating an azimuth with respect to the fixed station.