Transcript
GPS - FC GPS - DISCIPLINED FREQUENCY SYSTEM
Installation and User´s Guide
Version 1.0
000702AA
97-02-03
Efratom Elektronik GmbH Fichtenstraße 25 D-85649 Hofolding / Germany
Phone +49 - 8104 - 6624 -08 Fax +49 - 8104 - 6624 -28
Contents
Contents .............................................................................................................. Page 1.
Introduction GPS -FC ....................................................................................... 4 1.2 GPS Frequency Controller ......................................................................... 4 1.3 Squelch Function........................................................................................ 5 1.4 Interface / Starter Kit .................................................................................. 5
2.
Delivery Package .............................................................................................. 6 2.1 GPS-FC / Standard Unit ............................................................................. 6 2.2 Starter Kit / advanced Documentation ........................................................ 7
3.
Getting Started .................................................................................................. 8 3.1 Mounting the GPS-FC ................................................................................ 8 3.2 GPS-FC / Crossover Network .................................................................. 10 3.3 GPS-FC Starter Kit................................................................................... 12 3.4 Interface-Cable / Cable Length .................................................................13 3.5 Connecting the GPS-FC ...........................................................................14
4.
Operation .........................................................................................................16 4.1 Start-up .................................................................................................... 16 4.2 Start-up Failure......................................................................................... 16
5.
Technical Details ............................................................................................. 17
6.
Trouble Shooting ............................................................................................. 18
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Efratom Technical Support .....................................................................................20
GPS-FC - Installation and User´s Guide Version 1.0 / 97-02-03
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Safety Precautions / CE
GENERAL SAFETY PRECAUTIONS The following general safety precautions must be observed during all phases of the operation of this instrument. Failure to comply with these precautions violates safety standards of design, manufacture, and intended use of the instrument. Efratom assumes no liability for the customer’s failure to comply with these requirements. DO NOT OPERATE IN AN EXPLOSIVE ATMOSPHERE Do not operate the instrument in the presence of flammable gases or fumes.
KEEP AWAY FROM LIVE CIRCUITS Operating personnel should not remove instrument covers. Component replacement and internal adjustments should be made by qualified personnel. Do not replace with power cables connected. To avoid injuries, always disconnect power from the unit.
DO NOT SUBSTITUTE PARTS OR MODIFY INSTRUMENT Because of the danger of introducing additional hazards, do not install substitute parts, or perform any unauthorized modification to the instrument. Return the instrument to Efratom for service and repair to ensure that safety features are maintained.
The GPS-FC agrees with the EWG regulations 89/336/EWG: EN 50082-1 / EN 50082-2 EN 50081-1 / EN 50081-2
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Immunity: Emission:
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1. Introduction
1. Introduction GPS - FC 1.1 Global Positioning System The Global Positioning System (GPS) is one of the most accurate navigation system consisting of a network of 25 satellites. Each satellite is carrying accurate controlled atomic clocks for transmitting timing signals world wide. Any observer who can receive signals from four of these satellites can determine his accurate position on earth. In addition, the GPS technology enables many other timing and frequency applications.
figure 1.1: 25 satellites are rotating in 6 different orbits around the earth. The path radius of these satellites are about 26560 km (16504 miles).
1.2 GPS Frequency Controller
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The EFRATOM GPS-FC (GPS Frequency Controller) is a very compact GPS disciplined low cost frequency system. This smart system makes use of the accurate GPS timing signals and generates high performance frequencies. Antenna, GPS-receiver and oscillator are integrated in the same unit, which is suitable for mast mounting. The transmission of the frequency signal and the power supply are realized by only one coax cable. DC power is feeded into the cable and a precise frequency is received from the same cable. This concept allows a very easy installation and long distances from the receiver unit to the application. The GPS-FC is delivered in a very robust and waterproof aluminium die casting case and will perform under extreme conditions.
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1. Introduction
1.3 Squelch Function After locating the current position, the GPS-FC operates with a frequency accuracy of 1 x 10-11 (24 h average) even if only one satellite is received. In case of failure or loss of the GPS signal or any other system faults, the frequency output will be disabled (squelch). This facility prevents the output frequency from unserviceable signals. In this way the system guarantees the specified frequency during operation.
1.4 Interface / Starter Kit EFRATOM offers a special starter kit for frequency decoupling and power input optionally. This kit can be used as an interface for operation or system tests.
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The starter kit includes a test board, 10 m interface cable and the GPS User Guide´s with detail developers and GPS information (starter kit order number ETN84090000).
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2. Delivery Package
2. Delivery Package 2.1 GPS-FC / Standard Unit
GPS-FC / Standard Unit Power Supply
Part Number GPS - FC
+ 12 ... 36 V DC
+/- 36 ... 75 V DC
5 MHz
50 Ω
84000100
84000110
10 MHz
50 Ω
84000000
84000010
13 MHz
50 Ω
84000300
84000310
2048 kHz
G.703/10
75 Ω
84000400
84000410
2048 kbit/s
G.703/6
75 Ω
84000500
84000510
GPS-FC with one standard frequency output, mounting brackets for mast mounting and GPS-FC User´s Guide.
GPS-FC Assy: ◆ aluminium die casting case ◆ GPS antenna ◆ TNC connector female Mounting Assy for mast mounting: ◆ 4 x M8 fly-nuts ◆ 4 x M8 plain washer ◆ 2 x M8 mounting brackets
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◆ 2 x mounting flange (pre-assembled at the GPS-FC) Documentation: ◆ GPS-FC Installation and User´s Guide / short guide
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2. Delivery Package
2.2 Starter Kit / advanced Documentation GPS-FC / Starter Kit / Documenation Starter Kit
84090000
test board 10 m interface cable GPS User´s Guide
GPS User´s Guide
84090001
detailed user information
Starter Kit: ◆ test board for power supply and frequency decoupling ◆ 10 m interface cable ◆ GPS User´s Guide / detailed developer´s and GPS information (not available until now) GPS User´s Guide: ◆ GPS User´s Guide / detailed developer´s and GPS information
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(not available until now)
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3. Getting Started
3. Getting Started 3.1 Mounting the GPS-FC Location of the GPS-FC: ◆ The GPS antenna must be installed in a favourable area to receive the radio signals from the satellites. ◆ Select an outdoor location with a relatively unobstructed view - ”round view”- to the horizon. A good position could be the roof of your building or a detached mounting mast. (figure 3.1) ◆ Consider the length of the interface-cable. ◆ Protect the GPS-FC against lightning in case of thunder storms if necessary.
Pos. 1 Pos. 1 Pos. 2
Pos. 4
Pos. 3
figure 3.1: Influence of the antenna position refer to the GPS reception (2D schematic drawing)
Pos. 4
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The orbits of the GPS satellites are positioned more southern as northern to Europe. At northern areas of buildings or other restrictions could be shadow cones with no GPS reception. ◆ Position 1 (top of a building or antenna mast) guarantees a very good reception of GPS signals. Usually there are no restrictions to the horizon and up to 6 - 8 satellites could be received continuously. ◆ Position 2 is good enough to receive all necessary satellites for system operation. There are only partial interferences in reception of particular satellites. Up to 4 - 6 satellites could be received continuously. ◆ Position 3 is not recommended for continuous system operation. If the constellation of the GPS satellites is unfavourable according to the position of the antenna, the GPS reception breaks down and the system disables the output frequency. ◆ Position 4 (northern side of buildings, position with considerable restrictions to the horizon) is not suitable for system operation. In worse case no satellite could be received. The system disables the output frequency.
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3. Getting Started
Mount the GPS-FC: ◆ The mounting assy is designed for mast mounting. The diameter of the antennamast should be between 40 and 55 mm (figure 3.3). ◆ The mounting device is pre-assembled at the GPS-FC. ◆ All other parts of the mounting assy are included in the delivery package: - 4 x M8 fly-nuts - 4 x M8 plain washer - 2 x M8 mounting brackets ◆ Mount the GPS-FC at the upper end of the antenna-mast, the GPS antenna should rise above the mast. (figure 3.2)
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figure 3.2:
mast mounting
figure 3.3: GPS-FC mounting assy
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3. Getting Started
3.2 GPS-FC / Crossover Network The GPS-FC standard unit is delivered without interface cable, power supply and interface for frequency decoupling. This Manual describes, how to design a customer solution. A suggestion for the crossover network are shown at the following pages. The input voltage and the output level in dependence of the interface cable and the cable length are shown in section 3.3.
Note:
A short circuit fuse is designed at the GPS-FC board. Efratom recommends to design an additional fuse (1 A semi time-lag) close to the interface for easy changing in case of damage.
figure 3.4: Crossover Network GPS Antenna
GPS Frequency Controller
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Interface Cabel RG 58 / 50 Ω RG 59 / 75 Ω
DC Power Input 12 - 36 V DC or 36 - 75 V DC
Frequency Output Mounting Mast
GPS-FC - Installation and User´s Guide Version 1.0 / 97-02-03
Interface frequency decoupling
page 10
GPS-FC / Crossover Network / Interface
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figure 3.5: Crossover Network
3. Getting Started
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3. Getting Started
3.3 GPS-FC Starter Kit EFRATOM offers a special starter kit for frequency decoupling and power input optionally. This kit can be used as an interface for operation or system tests. The starter kit includes a test board, 10 m interface cable and the GPS User Guide with detail developer´s and GPS information. (starter kit order number ETN84090000). figure 3.6: Starter Kit LED Frequency
GPS-FC Input / TNC
Frequency Output / BNC
DC Power Supply
no in- or outputs
Front Panel
Rear Panel
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◆ LED Frequency: As soon as the output frequency is cleared the LED is ON In case of system faults, no GPS or system warm up the LED is OFF. The system disables the output frequency. ◆ GPS-FC Input: TNC-Connector to GPS-FC ◆ Frequency Output: BNC-Connector / frequency output ◆ DC Power Supply: Connector (dc + and dc -) for power supply (12 - 36 V or 36 - 72 V)
Note:
The dc-connector is internally connected to the metal case and to the shieldings of the BNC.
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3. Getting Started
3.4 Interface-Cable / Cable Length The input voltage of the power supply and the output level of the frequency output are depending on the interface-cable length. ◆ use RG58/U (50 Ω) for the frequencies 5, 10, 13 and 16 MHz ◆ use RG59/U (75 Ω) for the telecom outputs 2048 kHz and 2048 kbit/s Supply voltage: The supply voltage depends on the cable type and the cable length. Only lower supply voltages of each voltage range restrict the length of the interface cable - see table below: Interface Cable Length in dependence of the Supply Voltage Voltage Range
12 - 36 V
Us Cable Length
36 - 75 V
12 V
15 V
18 V
36 V
37 V
38 V
100 m
200 m
300 m
100 m
200 m
300 m
Output Level: The output level of the signal depends on the cable type, the cable length and the output frequency. The table below shows the approximate values of the attenuation in dB.
Attenuation of the Interface Cable Frequency
2048 kHz
5 MHz
10 MHz
13 MHz
16,384 MHz
RG58/U
< 1,5 dB
2 dB
2,5 dB
2,7 dB
3 dB
RG59/U
< 1,5 dB
1,5 dB
2 dB
2,3 dB
2,5 dB
RG58/U
< 3 dB
4 dB
5 dB
5,5 dB
6 dB
RG59/U
< 3 dB
3 dB
4 dB
4,5 dB
5 dB
RG58/U
< 6 dB
8 dB
10 dB
11 dB
12 dB
RG59/U
< 6 dB
6 dB
8 dB
9 dB
10 dB
50 m
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100 m
200 m Cable:
RG58/U / 50 Ω
/
RG59/U / 75 Ω
Example: level GPS-FC = 1 V
attenuation = 3 dB
output level = 0,7 V
level GPS-FC = 1 V
attenuation = 6 dB
output level = 0,5 V
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3. Getting Started
3.5 Connecting the GPS-FC ◆ prepare the interface cable (cable end to the GPS-FC: TNC-Connector female) ◆ connect the GPS-FC with the interface cable (type of cable -> 3.3) ◆ lock the connection cable <-> GPS-FC with the locking ring ◆ route the interface cable to the interface: - choose the direct way to the interface (prefer shorter cable length) - route the cable without sharp bends or kinks - route the cable under considering the cable specifications ◆ cut the cable at the interface: - leave some slack to allow easy connection - mount the user defined connector at the cable end ◆ turn off the dc power of the interface and connect the cable with the interface
user defined
Interface TNC-Connector female TNC-Connector Frequency Output Interface Cable
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Power Supply
figure 3.7: GPS-FC Connection
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3. Getting Started
Connecting GPS-FC <-> Starter Kit ◆ prepare the interface cable (cable end to the GPS-FC: TNC-Connector female) ◆ connect the GPS-FC with the 10 m interface cable / TNC-Connector ◆ lock the connection cable <-> GPS-FC with the locking ring ◆ route the interface cable to the interface: - route the cable without sharp bends or kinks ◆ turn off the dc power of the interface and connect the cable with the starter kit / TNC-Connector ◆ turn on the dc power (12-36 V) for warm up
TNC-Connector female TNC-Connector
Starter Kit Antenna Input / TNC Frequency Output / BNC
Interface Cable
Power Supply
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figure 3.8: GPS-FC <-> Starter Kit Connection
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4. Operation
4. Operation After mounting the GPS-FC, preparing the interface and routing the interface cable the system can be set into operation. The system operates automatically in case of DC power is connected. ◆ feed the interface with the supply voltage. The supply voltage depends on the voltage range of the GPS-FC (12 - 36 V or 36 - 75 V)
4.1 Start-up Cold Start - First Warm Up As soon as the system is supplied with dc power the GPS-FC is warming up. The GPS receiver starts scanning the horizon to find one of the GPS satellites. The first satellite transmits the almanac data (position informations) of the other satellites and assists in finding them. After receiving the signals of four satellites the receiver determines the position of the antenna. This procedure requires about 30 minutes (worse case up to 1 hour). The system is provided with the GPS time information and regulates a crystal oscillator (VCXO) with the help of special developed algorithms. As soon as the VCXO is locked to GPS, the frequency output will be cleared. The system is ready for operation. Warm Start - Warm up The GPS-FC preserves the last available position and satellite data in memory. After power up the GPS receiver has all necessary informations to find the satellites in a few minutes. The VCXO will be locked to GPS and the frequency output will be cleared. A warm start requires about 5 - 10 minutes (worse case up to 20 minutes).
4.2 Start-up Failure
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In case of correct installation, valid power supply and operative interface the output frequency will be cleared automatically after warm up. The output frequency won’t be cleared if any component is defect or wrong connected. Please check all steps in section 3. (getting started) and section 4. (operation) or get some information in section 6. (trouble shooting). trouble shooting -> section 6.
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5. Technical Details
5. Technical Details Environmetal Specification:
Performance Specification:
Operating Temp.:
-30° C ... + 75°C
Storage Temp.:
-40° C ... + 85°C
GPS Unit 6-channel C/A-Code-Receiver, tracks up to 8 satellites continuously. Input Freq.: 1575.42 MHz (L1) Antenna: special GPS Antenna
Technical Specification: Power Supply:
+ 12 ... 36 V DC or +/- 36 ... 75 V DC
Frequency Output: 1 x 5 MHz sine 1 Vrms / 1 x 10 MHz sine 1 Vrms / 1 x 13 MHz sine 1 Vrms /
50 Ω 50 Ω 50 Ω
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Telecom Output: 1 x 2048 kHz G.703/10 75 Ω 1 x 2048 kBit/s G.703/6 75 Ω The 1 Vrms output level is related to the TNC connector at the GPS-FC case.
Oscillator:
Type: VCXO
Freq. Accuracy:
1 x 10-11 (24 h average)
Warm start:
< 20 min (typical)
Cold start:
< 1 h (after installation)
Physical Characteristics: Size:
height x width: 180 x 160 mm depth: 90 mm
Weight:
1800 g
Case
The GPS-FC case is a very robust and waterproof aluminium die casting case.
Connector
TNC / female
Cable
RG58/U RG59/U
50 Ω 75 Ω
figure 5.1: Size GPS-FC
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6. Trouble Shooting
6. Trouble Shooting In case of correct installation, valid power supply and operative interface the output frequency will be cleared automatically after warm up. The output frequency won’t be cleared if any component is defect or wrong connected.
No Frequency after first start up the first start up requires up to 1 hour
no frequency after one hour: 1. switch off and try start up again
wrong or no supply voltage
2. check GPS-FC voltage range at the device label (12 - 35 V or 36 - 75 V) -> section 3.2, 3.3 3. check power supply 4. check current of the device - power consumption should be between 2 W and 5 W!
no GPS signals available
5. check position of GPS-FC antenna -> section 3.1
faulty connection GPS-FC <-> interface
6. check cable connections GPS-FC <-> interface cable interface cable <-> interface
defect or wrong interface cable
7. check interface cable -> section 3.4, 3.5
defect or wrong interface
8. check interface -> section 3.2 9. try the Efratom starter-kit interface if possible -> section 3.3
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10. contact Efratom Elektronik GmbH
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6. Trouble Shooting
No Frequency after warm start a warm start requires up to 20 minutes
no frequency after 20 minutes: 1. switch off and try start up again
no GPS signals available
2. check position of GPS-FC antenna -> section 3.1
faulty connection GPS-FC <-> interface
3. check cable connection GPS-FC <-> interface cable interface cable <-> interface
defect interface cable
4. check interface cable -> section 3.5
defect interface
5. check interface -> section 3.2 6. try the Efratom starter-kit interface if possible -> section 3.3
defect supply voltage
7. check power supply 8. check current of the device - power consumption should be between 2 W and 5 W! 9. contact Efratom Elektronik GmbH
No Frequency during operation 1. check position of GPS-FC antenna -> section 3.1
faulty connection GPS-FC <-> interface
2. check cable connection GPS-FC <-> interface cable interface cable <-> interface
defect interface cable
3. check interface cable -> section 3.5
defect interface
4. check interface -> section 3.2 5. try the Efratom starter-kit interface if possible -> section 3.3
defect supply voltage
6. check power supply 7. check current of the device - power consumption should be between 2 W and 5 W!
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no GPS signals available
8. contact Efratom Elektronik GmbH
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Technical Support
Efratom Technical Support Efratom Elektronik GmbH Fichtenstrasse 25 D-85649 Hofolding / Germany +49 - 8104 - 6624 - 0 +49 - 8104 - 6624 - 28
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Phone: Fax:
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