| 1a. Spacecraft orbit |
600 x 600 km at 38 deg inclination |
N/A |
| 1b. Station location |
Berkeley, California (37.9 deg North, 122.2 deg West) |
N/A |
| 1c. Compatibility |
It is required that the ground station be compatible with the HESSI spacecraft, built
by Spectrum Astro.
It is required that the ground station perform the required telemetry decoding and command encoding.
It is required that the ground station be compatible with back-up ground stations.
Compatibility requirements refer to the specifications stated in this document and in pertaining CCSDS and NASA
Spacecraft Tracking and Data Network (STDN) documents. |
Explain how the proposed ground station meets the requirement. |
| 2. Antenna |
An antenna system with a parabolic reflector and a three-axis drive system is required. |
Provide design drawing. |
| 2a. Antenna reflector |
A 10 m diameter (or larger) parabolic dish with solid surface (no wire mesh) is required. |
Provide design drawing. |
| 2b. Antenna pedestal |
It is required that the height of the bottom edge of the antenna reflector in the
zero elevation position be not less than 3 feet above the base of the pedestal in order to clear obstructions at
the site. |
Provide design drawing. |
| 2c. Antenna drive |
A three axis drive (Azimuth/Elevation/Tilt, Cross Elevation/Elevation/Azimuth or
X/Y/Rotate) is required in order to support zenith passes. Tracking is not required on the third axis. It is required,
however, that the third axis can be positioned under computer control as part of a pre-pass setup. |
Provide design drawing. |
| 2d. Drive speed |
It is required that the drive speed in azimuth and elevation angles be at least 10
deg/sec and the acceleration be at least 20 deg/sec2. * |
Document performance. |
| 3. Radome |
A radome is not required. However, if a radome is included in the proposal, the radome
loss must not be larger than 0.5 dB. |
Provide design drawing and RF data sheets. |
| 4. Operation |
It is required that the antenna be operated under all normal weather conditions including
heavy rain. |
Provide specifications. |
| 4a. Temperature |
It is required that the antenna be operated with ambient temperatures between 0 C
and +50 C. |
Provide specifications. |
| 4b. Wind speed |
It is required that the antenna be operated with wind speeds up to 40 mph with the
pointing accuracy specified below. The antenna is required to survive wind speeds up to 120 mph in the stow position. |
Provide specifications. |
| 4c. Safing operation |
It is required that the ground station will perform a safing operation (automated
stow operation) in such a way that the antenna be moved into the stow position when the wind speed exceeds the
limit that is safe for operation. |
Explain proposed solution. |
| 4d. Pointing accuracy |
It is required that the total pointing error of the antenna be 0.05 deg or less (3
sigma rms) in tracking mode using track files (see below).
It is required that the orthogonality of the axes of rotation be 0.01 deg or less.
It is required that a detailed error budget be supplied with the proposal, stating what the contributions resulting
from back-lash in the gears, bearing wobble, gravity droop and thermal deformations are. |
Provide measured performance data. |
| 4e. Tracking |
It is required that the antenna can perform autotracking with a scan along track
and a spiral or raster scan. It is required that the antenna can lock onto the spacecraft while data are transmitted
at a rate of 2 Msymbols/sec at a range of 2400 km. It is required that the antenna can point at the spacecraft
in autotracking mode with an accuracy of 0.1 deg (3 sigma rms).
It is required that in autotracking mode the instantaneous azimuth and elevation angles, and the lock status can
be read out in real-time and are also recorded in a file.
It is required that the antenna can perform program tracking functions via track files. The finest time steps in
the track files be 0.1 seconds or shorter. It is required that the antenna control unit can also be operated in
real-time tracking mode (slave mode), in which azimuth and elevation angles can be sent to the antenna controller
at least 10 times per second. The time delay between receiving of the look angles and acquiring of the commanded
position in real-time mode must not be longer than 0.1 seconds, assuming small differential motions.
It is required that the autotracking functions and the interaction between autotracking, program tracking and scan
comprise user configurable items (e.g. autotrack threshold; resume program tracking if spacecraft is lost in autotracking
mode; resume raster scan or scan along track if spacecraft is lost in program tracking mode). |
Explain proposed solution and show measured performance. |
| 5. Communications |
It is required that all links between the equipment racks installed inside the Mission
and Science Operations Center (MSOC) and the equipment installed at the antenna site are fiber-optic links (RS-232
pedestal control link, video links, microwave fiber-optic link for transmit and receive). The length of each fiber-optic
cable is less than 1200 ft. |
Explain proposed solution and provide itemized equipment list. |
| 6. RF Frontend |
It is required that the antenna be equipped with receivers, transmitter and feed
systems. |
N/A |
| 6a. Frequency range |
S-Band
Downlink band 2200-2290 MHz
Uplink band 2025-2110 MHz
Wider band coverage is acceptable. *
Full-duplex operation of the ground station for telemetry reception and command uplink is required. |
N/A |
| 6b. RF feed |
Required polarizations are RHCP and LHCP (simultaneous for downlink, switchable for
uplink).
It is required that the RF feed be hermetically sealed from the environment (moisture). A circular waveguide feed
horn is desired.
It is required that the axial ratio for circular polarization be 1.2 dB or less. *
It is required that the isolation between transmit and receive path be 90 dB or larger. * |
Explain proposed solution. |
| 6c. Side lobe levels |
Side lobe levels are required to be 26 dB or less between 3 and 20 deg and 46 dB
or less between 20 and 180 deg from center of main lobe in azimuth and elevation. |
Provide measured performance. |
| 6d. Downlink channel |
| Receiver G/T: |
23 dB/K at 10 deg elevation (without atmospheric loss, and if a radome is proposed,
without radome loss) * |
| Polarization: |
RHCP and LHCP (simultaneously) |
| Data rate: |
4000 kbps (8000 ksymbols/s) and
1000 kbps (2000 ksymbols/s) |
| Data format: |
NRZ-M |
| Bit error rate: |
10-5 or less |
| Downlink modulation: |
BPSK |
| Implementation loss: |
2 dB or less |
| Compatibility: |
CCSDS |
| Coding: |
Reed-Solomon (255,223), (Interleave depth = 5) outer code plus Convolutional (Rate
= 1/2, Constraint length = 7) inner code with Viterbi (maximum-likelyhood) decoding |
|
|
|
Explain proposed solution and provide itemized equipment list. |
| 6e. Uplink channel |
| Transmit power: |
59 dBW EIRP or larger (adjustable) (without radome loss, if radome is proposed)
Upgrade option to 62 dBW EIRP is desired. * |
| Polarization: |
RHCP and LHCP (switchable) |
| Data rate: |
2 kbps |
| Data format: |
NRZ-L, NRZ-M and NRZ-S |
| Uplink modulation: |
BPSK/PM with 16 kHz sub-carrier |
| Modulation index: |
0.5 - 1.3 rad (adjustable) |
| Compatibility: |
CCSDS |
| Coding: |
None |
|
|
It is required that the transmitter can be keyed up without modulation, and that the modulation (data transmission)
can be started with a selectable time delay.
Since the spacecraft receiver has no sweep capability, it is required that the uplink frequency can be swept at
a rate of 35 kHz/s or less and programmed in steps of 100 Hz up to 10 times per second in order to provide the
correct Doppler compensation. |
Explain proposed solution and provide itemized equipment list. |
| 7. Data handling |
It is required that the ground station functions autonomously for both telemetry
reception and command uplink.
It is required that the ground station can store 8 GBytes of data locally.
It is required that the ground station can transfer telemetry data in real-time, in buffered and in playback mode
via TCP/IP connections.
It is required that the commands sent to the spacecraft and telemetry data frames received from the spacecraft
are time-tagged with an absolute accuracy of 1 millisecond or better with respect to UTC.
A data quality monitor, i.e. statistical analysis for telemetry data streams is required, in order to allow management
of retransmissions on the downlink channel.
Data are to be transferred to the MSOC according to user defined priorities by Virtual Channel (VC) or packet IDs.
The ground station will be able to forward designated VCs in real-time and other VCs as part of the post-pass operations.
A flexible routing scheme, i.e. definition of multiple Internet Protocol (IP) addresses is required for selecting
data flows from the ground station to the primary and back-up workstations at the MSOC.
It is required that the ground station can be configured by the user to assume the role of a server or a client
in order to handle data transfers.
It is required that the encapsulation of transfer frames is configurable.
A handshake capability, i.e. acknowledge receipt of data, is required for downlink and uplink.
It is required that the ground station can support both real-time and stored command uploads to the spacecraft. |
Explain proposed solution and provide itemized equipment list. |
| 8. Timing subsystem |
A GPS receiver with IRIG-B timecode and 5 or 10 MHz reference frequency output is
required. |
Explain proposed solution and provide itemized equipment list. |
| 9. Simulation |
It is desired that the ground station has a self-test capability (full RF loop-back
and bit error rate test) to insure proper functionality as part of the pre-pass configuration. |
Explain proposed solution and provide itemized equipment list. |
| 10. Redundancy |
It is required that the station has redundant equipment (telemetry receivers, bit
synchronizers, telecommand generators, sub-carrier generators, data processing computers). |
Explain proposed solution and provide itemized equipment list. |
| 11. Power supplies |
Uninterruptible power supplies are required for essential subsystems (computers,
telemetry receivers, diversity combiner, bit synchronizers, timing subsystem, computers and workstations). |
Explain proposed solution and provide itemized equipment list. |
| 12. Software |
It is required that the ground station can be accessed through a high-speed communications
link for telemetry reception from the spacecraft, command forwarding to the spacecraft, and for transfer of antenna
track files and control and monitoring of the ground station itself. All housekeeping and status information of
the ground station has to be available via TCP/IP connections.
It is required that the ground station can process track files similar to those used to control the antenna pointing
for setting the frequencies of the telemetry receivers and for the command transmitter, and for switching the sense
of polarization of the command uplink feed. |
Explain proposed solution. |
| 13. Ephemeris products |
For generation of all mission critical ephemeris products (orbit event files, pass
schedules, track files, real-time world map display, orbit determination, etc.), the SatTrack software suite has
already been selected. This software will run on dedicated computers in the MSOC. An additional orbit analysis
and scheduling software package is therefore not required as part of the ground station. The SatTrack package is
provided and maintained by BTS. |
N/A |
|
|
|
| 14. Telemetry and command |
The telemetry and command processing system of the ground station is required to
be compatible with the MSOC Integrated
Test Operating System (ITOS). The ground station will deliver decoded
CCSDS telemetry transfer frames or packets to ITOS for decommutation and will receive CCSDS command transfer frames
from ITOS for encoding and transmission to the spacecraft. Command uploads will be generated with the Command Management
System (CMS). Both ITOS and CMS will be provided by NASA/GSFC. |
N/A |
| 15. Messaging |
It is required that a warning message is sent to the MSOC, in case an anomaly in
the operation of the ground station occurs. |
Explain proposed solution. |
| 16. Environment monitor |
If no radome is proposed, a weather station is required to measure wind speed and
direction, atmospheric pressure, ambient temperature and relative humidity.
Security and surveillance cameras that can provide images several times per second are required.
Weather data and camera images have to be available via Ethernet. |
Explain proposed solution and provide detailed equipment list. |
| 17. Facility |
The antenna site will be provided and prepared by the University. |
N/A |
| 17a. Electrical power |
Detailed specifications on the electrical power requirements of the ground station
have to be made available to the University as part of the proposal. |
Provide detailed specifications. |
| 17b. Grounding scheme |
It is required that the antenna allows proper grounding for lightning protection.
The underground segment of the grounding network will be provided by the University. |
Provide detailed specifications. |
| 17c. Foundation |
Detailed specifications on the foundation for the antenna (wind load, size of concrete
block, bolt pattern, etc.) have to be made available to the University as part of the proposal. |
Provide detailed specifications. |
| 17d. Site preparation |
The antenna site preparation will be carried out by the University. The site preparation
includes building the concrete foundation for the antenna, and installation of fencing, lighting, grounding, pavement
of the immediate area around the antenna pedestal, electrical power (220/110 V service), and communications lines.
Ducts for fiber-optic and/or coaxial cables will be provided by the University. The fiber-optic and/or coaxial
cables will be provided by the vendor of the ground station. |
Explain proposed solution and provide detailed equipment list. |
| 17e. Installation |
It is required that the ground station will be installed and checked out at Berkeley,
California no later than July 31, 1999.
It is required that all electronics components except for the low-noise pre-amplifiers, the high power transmit
amplifier, and the antenna controller are located inside the MSOC in the SSL building. The mentioned equipment
be installed inside the antenna pedestal or attached to the antenna mount in a weather-proof and temperature stabilized
enclosure.
One television camera be installed on a mast at the antenna site. This mast is provided by the University. If a
radome is proposed, a second camera will be installed inside the radome.
In case no radome is proposed and a weather station is required, this weather station be installed on the roof
of the MSOC.
The antenna for the GPS receiver will be installed on the roof of the MSOC. |
Explain proposed solution and provide detailed equipment list. |
| 18. Life time |
The useful life time for the antenna sub-system is required to be at least 5 years.
This includes the RF feed system, motors, gears, bearings, cables, the surface coating (paint), and the radome
(if included in the proposal). |
Certify performance. |
| 19. Documentation |
It is required that the University will receive a detailed Interface Control Document
(ICD) for the entire ground station no later than one month after the contract is awarded. |
Provide detailed ICD. |
| 20. Support |
It is required that the vendor of the ground station will support the HESSI team
in activities related to application for an NTIA license, preparation of the antenna site, operation of the ground
station, program reviews and studies, and during spacecraft integration and testing and launch and early orbit
operations.
The HESSI program requires back-up support for telemetry downlink and spacecraft commanding, in case the Berkeley
ground station becomes temporarily unavailable. It is desirable that the vendor of the ground station also operates
a network of ground stations, so that back-up support can be provided through this network.
If the vendor of the Berkeley ground station is not able to provide this back-up support, the proposal has to state
what the differences, if any, are between the proposed Berkeley ground station and existing NASA ground stations
that are suitable for back-up support.
It is desirable that the vendor of the ground station will make an existing ground station available prior to the
installation of the ground station at the University, so that interface and end-to-end tests via TCP/IP connections
can be carried out periodically. |
Explain proposed solution and describe nature of proposed support. |
| 21. Quotation |
It is required that the quotation for the ground station is based on a fixed price.
It is required that the quotation is broken down by line items.
Costs for support of the HESSI team and for back-up and maintenance support shall be itemized.
It is required that differences in price (if any) between the original quotation (if applicable) and the new proposal
are stated. |
Provide itemized costs. |
|
|
|
