Next Generation Earth Stations Pointing the Way Presented by Andrew Smith President Kratos Integral Systems International Ltd. United Kingdom
Pointing the Way Two main subject areas: 1. Antenna Design & Manufacture 2. Earth Station System Architecture 1
Pointing the Way 1. Antenna Design & Manufacture 2
Earth Station Heritage Kratos ISI UK has supplied earth stations to the global industry since 1982. Our heritage can be traced back to the start of commercial satcoms in the 1960 s. 3
Earth Station Heritage We used to design and make our own antennas in UK until 1990. 13m LMA 15.5m HWS THA 15.5m LMA 11m FMA 6.4m FMA 4
Third-Party Manufacture Today, we have antennas made to our specifications in third-party factories in China. This offers huge benefits: Antennas can be made using traditional design concepts which have had to be abandoned by most vendors on grounds of cost. Very accurate structures are made, because the accuracy comes from machining in the factory. This is further enhanced by factory trial assembly. Reflectors are made from stretch-formed skins. Ball-screw jacks for smooth, precision, high-speed axis movement once again become affordable. We paint over the galvanised steel finish as standard. Any many other features besides. 5
Reflector Panel Manufacture Stretch-formed panel skins Rivetted construction Rivetted and bonded for higher frequency application 6
Linear Actuators Machine Screw vs. Ball Screw Machine Screw Ball Screw 7
Platform Deck We use fabricated deck panels. not expanded metal sheet. 8
Tubular Reflector Support Structure 9
Tubular Reflector Support Structure 10
Antenna Parts Shipped as Major Subassemblies 11
Fast On-Site Assembly 12
Fast On-Site Assembly 13
Fast On-Site Assembly 14
What we deliver are antennas that are thermally stable 15
What we deliver are antennas that can more easily be maintained 16
What we deliver are antennas that can readily be customised for unusual installation environments 17
What we deliver are antennas that go together easily on site (as a result of factory trial assembly) 18
What we deliver are antennas that change the economic balance between antenna size and HPA power 19
What we deliver are antennas that fully support their design lifetime 20
What we deliver are antennas that do what the specification says 21
Additional benefits For challenging environments, we can use carbonfibre panels For Q/V band operations, this would certainly be considered 22
Additional benefits We can fully characterise the antennas in an outdoor test range with 300m and 18km path lengths. 23
Additional benefits For feed RF testing and for near-field testing of small antennas we have access to anechoic chambers. This one is characterised from 30MHz to 100GHz. 24
Additional benefits The facilities offered by using these factories allow us to offer the kind of antenna engineering approach that was only affordable in the era before Telco deregulation. 25
Additional benefits The facilities offered by using these factories allow us to offer the kind of antenna engineering approach that was only affordable in the era before Telco deregulation. but today we can do this for the price of a standard production antenna. 26
Pointing the Way 2. Earth Station System Architecture 27
Design Considerations A larger antenna allows the power amplifier to be smaller for the same EIRP. 28
Antenna/HPA Trade-Offs for 90dBW EIRP Prime Power Cost over 15 years for a redundant HPA pair Antenna Size (m) HPA RF Power (W) Prime Power Cost (kusd) * 7.3 2000 300 9.0 1250 235 13.0 650 95 (* Assumes USD 0.15 per KWh) 29
Design Considerations A larger antenna allows the power amplifier to be smaller for the same EIRP. We can go a few steps further: Use a low-power broadband tube amplifier or a solid state power amplifier if the levels allow Put the power amplifiers in the antenna (with a larger antenna this becomes easier) Add a BUC If the link budget doesn t quite make it for the Contingency case, add a CP/LP switch. With our solutions this is relatively inexpensive. You can get nearly 3dB additional gain from this. Hub-mount is current practice for Ka-band because there isn t really an alternative. But it can be done for C-, X-, Kuand DBS-Bands too. Now we have the entire earth station in the antenna, with an L-Band interface. 30
Earth Station in an Antenna 31
Earth Station in an Antenna 32
Earth Station in an Antenna 33
Earth Station in an Antenna 34
Architecture Considerations Many users would prefer to have their TT&C modems in a central location for several reasons (maintenance logistics, security, etc.). It s been possible to do this for some time, using RF over Fibre systems either at IF or L-Band. But the fibre cost can be prohibitive especially for conventional commercial applications. The Kratos SpectralNet product is a game-changer. RF over IP Can use corporate WAN or the public Internet Lossless error-free reconstruction of the RF signal at the distant end Available for IF and L-Band systems So now you can have the Earth Terminal in an Antenna at the Earth Station site, and the TT&C modems at your company Operations Centre. 35
RF over IP System Architecture 36
RF over IP System Architecture 37
Use a bigger antenna with a smaller amplifier The bigger antenna offers you a better downlink margin You pay for the bigger antenna only once On the other hand you pay forever for the power consumed by powerful amplifiers The link budget can economically be enhanced by CP/LP switching The narrower beam enhances your orbit determination accuracy potential The architecture of such a solution fits hand-in-glove with an RF over IP terrestrial back-haul to the TT&C modems The amount of equipment at the Earth Station site is minimized. Whether that is 100 metres away or 100 miles away it provides operational benefits and simplifies maintenance. Get your EIRP using metal and not Watts Conclusions 38
United Kingdom Kratos Integral Systems International Ltd. 17 Princes Park, Fourth Avenue Team Valley, Gateshead Tyne & Wear, NE11 0LQ United Kingdom Phone: +44 191 497 7760 Fax: +44 191 497 7769 France Kratos Integral Systems Europe S.A.S. 57 Rue Marco Polo 31 670 Labège Cedex France Phone: +33 5 61 00 22 10 Fax: +33 5 61 00 22 12 USA Kratos Integral Systems International, Inc. 5200 Philadelphia Way Lanham, Maryland 20706 Phone: +1 443.539.5330 Fax: +1 410.312.2705 Website: www.kratos ISI.com Corporate Headquarters 4820 Eastgate Mall San Diego, California 92121 Phone: +1 858.332.3700 Website: www.kratosdefense.com 39