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Space Flight Technology, German Space Operations Center (GSOC)
Deutsches Zentrum für Luft- und Raumfahrt (DLR) e.V.
User’s Manual for the GPS
Orion-S/-HD Receiver
O. Montenbruck, M. Markgraf
Doc. No. : GTN-MAN-0110
Version : 1.0
Date : June 22, 2003
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Document Title: ii User’s Manual for the GPS Orion-S/-HD Receiver Document Change Record Issue Date Pages Description of Change 1.0 June 22, 2003 all First release Disclaimer Information in this manual has been compiled with adequate care and represents the best knowledge of the authors. Any errors remaining after its release will be fixed upon notifica- tion. In no way shall DLR or the authors be held liable for direct or indirect damage result- ing fr
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Document Title: iii User’s Manual for the GPS Orion-S/-HD Receiver Table of Contents Document Change Record...................................................................................................... ii Table of Contents.................................................................................................................... iii Scope and Applicability .......................................................................................................... 1 Acronyms
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Document Title: iv User’s Manual for the GPS Orion-S/-HD Receiver 4.3.4.3 LO – Load Orbit...............................................................................................................................30 4.3.4.4 TO – Transmit Orbit........................................................................................................................30 4.3.4.5 LE – Load Epoch.......................................................................................................
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Document Title: 1 User’s Manual for the GPS Orion-S/-HD Receiver Scope and Applicability This manual provides a user’s guide for the DLR’s GPS Orion receivers for space and high dynamics applications. It describes the hard and software interfaces required for operating the receiver in standalone and embedded applications. Information in this document supple- ments and supercedes related sections of the GPS Orion Product Brief [1] and the GP2000 Series Demonstrator Board User’s Guide [2]
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Document Title: 2 User’s Manual for the GPS Orion-S/-HD Receiver Acronyms and Abbreviations A Ampere AGC Automatic Gain Control ASCII American Standard Code for Information Interchange C/N Carrier-to-Noise Ratio 0 COM Communication dB Decibel DC Direct current DLR Deutsches Zentrum für Luft- und Raumfahrt EPROM Erasable Programmable Read Only Memory FLL Frequency-Locked Loop GPS Global Positioning System GSOC German Space Operations Center I/F Intermediate Frequency IIP Instan
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Document Title: 3 User’s Manual for the GPS Orion-S/-HD Receiver 1. Introduction 1.1 GPS Orion Receiver The GPS Orion receiver represents a prototype design of a terrestrial GPS receiver for 12 channel single frequency tracking built around the Mitel (now Zarlink) GP2000 chipset ([3], [4]). The receiver main board comprises a GP2015 frontend and DW9255 saw filter, a GP2021 correlator as well as an ARM60B 32-bit microprocessor. It can be supplemented by an optional interface board featur
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Document Title: 4 User’s Manual for the GPS Orion-S/-HD Receiver • Small form factor (50 x 95 mm) and weight (50 g) • Sufficient radiation tolerance LEO usage • Battery buffered non-volatile memory and real-time clock • Two serial ports • Discrete input pin • 5V supply for active antenna (16-28dB) • OrionMonitor control software for Windows PCs A hardware description of the Orion-S/HD receiver is provided in Chap. 2 of this manual. Chap.3 addresses the receiver operation and the comma
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Document Title: 5 User’s Manual for the GPS Orion-S/-HD Receiver 2. Receiver Hardware 2.1 Main Board A block diagram of the GPS Orion receiver main board is shown in Fig. 2.1 ([4]). The receiver is designed to work with an active antenna and +5 V power supply for the preamplifier is pro- vided on the central antenna feed. Fig 2.1 Block diagram of the GPS Orion receiver main board (from [4]) After passing an R/F ceramic filter, the L1 signal (1575.42 MHz) is down-converted and digi- ti
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Document Title: 6 User’s Manual for the GPS Orion-S/-HD Receiver RAM memory. The EPROM is arranged into two 16 bit wide chips (256 kB total), while RAM is partitioned into four 8 bit wide memory chips with a total size 512 kB. The RAM memory contents can be maintained by a dedicated backup power supply line with a current of ap- proximately 0.1 mA. The main board offers an SMA (or MCX) connector for the GPS antenna. It is connected to the interface board via a 9-pin header that provides
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Document Title: 7 User’s Manual for the GPS Orion-S/-HD Receiver 2.2 Interface Board The interface board provides auxiliary devices that are required for standalone operation of the Orion receivers. It comprises • a switching regulator allowing operation from unregulated power supplies, • a rechargeable battery to maintain the non-volatile memory and real-time clock during power down times and • two RS232 serial line drivers for communication with standard peripheral devices. Key par
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Document Title: 8 User’s Manual for the GPS Orion-S/-HD Receiver 3. Operations Guide 3.1 Basic Receiver Handling 3.1.1 Hardware Setup For operating the GPS Orion receiver in a ground based test environment, the following hardware items are typically required: • Orion main board • Orion interface board with power cable • Power supply or battery (typically +12 V, 250 mA) • Active GPS antenna (ca. 26 dB gain) with cable and SMA (or MCX) connector (male) • PC with Windows operating syst
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Document Title: 9 User’s Manual for the GPS Orion-S/-HD Receiver For proper communication, these values must match the settings of the PC communication port. While the Orion receiver is most conveniently used via a dedicated monitoring and control program (e.g. OrionMonitor), elementary operations may likewise be carried out via a stan- dard terminal program. As an example, the HyperTerminal program provided with the Win- dows operating systems can be used to monitor receiver output messag
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Document Title: 10 User’s Manual for the GPS Orion-S/-HD Receiver • If the above steps have taken more than two minutes, the receiver may have started to scan through the permitted range of frequency bins. Reset or reboot the receiver to start the signal search in the central frequency bin. • Select the desired aiding mode (using the AM command). • Set other operations parameters (e.g. output rates, elevation mask, etc.) as desired. The receiver should now be indicating proper tracking a
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Document Title: 11 User’s Manual for the GPS Orion-S/-HD Receiver 3.1.6 Pulse-per-Second Signal Supporting receiver versions provide a one-pulse-per-second signal (CMOS TTL level) at pin 10 of the interface connector. The PPS signal is available in case of valid navigation. It has a one millisecond duration and its starting edge is aligned to the occurrence of an integer GPS second with an accuracy of better than 1 μs. The typical error amounts t ca. 0.2 μs and is determined by the limit
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Document Title: 12 User’s Manual for the GPS Orion-S/-HD Receiver 3.2 Special Applications 3.2.1 Aiding for Ballistic Trajectories To allow a rapid acquisition and an optimal channel allocation in case of high vehicle dynam- ics the Orion-HD receiver can be aided by a priori trajectory information. For sounding rock- ets or other ballistic missions the nominal flight path is represented by a piecewise, low order polynomial approximation stored within the receiver (Fig. 3.1, [12]). Using th
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Document Title: 13 User’s Manual for the GPS Orion-S/-HD Receiver nals and ensures near-continuous tracking throughout the boost and free-flight phase of the ballistic trajectory. The command interface of the Orion-HD receiver supports a total of six different instructions to support the handling of ballistic trajectory information: • The LT (Load Trajectory) command initiates the upload of a set of trajectory polyno- mials. • Each trajectory polynomial is then loaded in the form a singl
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Document Title: 14 User’s Manual for the GPS Orion-S/-HD Receiver play of the IIP allows the range safety officer to discern whether the rocket would eventually land outside the permissible range area and thus necessitate an abort of the boosted flight or even a destruction of the malfunctioning vehicle. For an optimal support of sounding rockets, the Orion-HD receiver is able to predict the in- stantaneous impact point (IIP) from its navigations solution. The instantaneous position and v
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Document Title: 15 User’s Manual for the GPS Orion-S/-HD Receiver 3.2.4 Aiding for LEO Satellites The Orion-S receiver provides a dedicated aiding mode to support the GPS signal acquisition onboard a low Earth orbiting (LEO) satellite. Similar to the HD receiver, it uses a coarse ap- proximations of the nominal trajectory to forecast the visible GPS satellites and the expected line-of-sight Doppler shift. This information is the used to allocate and initialize new tracking channels. In ac
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Document Title: 16 User’s Manual for the GPS Orion-S/-HD Receiver Aided operation of the Orion-S receiver is supported by a variety of dedicated commands: • For configuring the orbital elements of the user satellite, the LO (Load Orbit) com- mand is used. The first and second line of the elements set are each embedded into a separate LO command and consecutively transmitted to the receiver. • Using the TO (Transmit Orbit) command the currently loaded mean orbital elements can always be d
