Gemini Frequently Asked Questions

1) Can Gemini measure Bit Error Rate (BER)?
Gemini will log whatever data the radio terminal produces however most TETRA radios do not make this parameter available. In addition, the BER figure that you may see on the radio display when in engineering mode is derived from a set of just 22 'Training Sequence' bits used to optimise the internal filters and because it is based on such a small number of bits the BER figure is not generally regarded as statistically valid and suitable for measuring network performance. In comparison, voice quality measurements effectively measure the quality of the full data throughput and is generally regarded as a much better measure of channel performance.

2) Does Gemini log the time-slot?
As before, most TETRA radios do not make this parameter available via the PEI port therefore Gemini is unable to log it.

3) How often is RSSI logged and how is it calculated?
RSSI is calculated internally by the TETRA radio terminal typically every 1 sec. Gemini requests the RSSI from the radio terminal so that each call event is logged with the most recent RSSI value.

4) What TETRA terminals is Gemini compatible with?
Gemini is compatible with the following TERA radio terminals:
Cleartone CM9000
Sepura SRP2000
Motorola MTM700
Any other TETRA terminal with a standard PEI port should be compatible with Gemini

5) Can Gemini be used for indoor surveys?
Yes it can. An ideal configuration is to use a PC tablet together with the Sepura SRP2000 radio to make a very portable system. Gemini can be run without GPS if preferred for indoor working - in this case rooms can be surveyed individually and the results summarised for each room on graphs or tables.

6) Can Gemini results be viewed in MapInfo?
Gemini supports export of data in a number of text formats which may be imported to MapInfo.

7) Are any other software packages needed to view or analyse Gemini data?
No. Gemini contains as standard sophisticated analysis and mapping/graphing functionality.

8) Can the raw Gemini data be accessed for further analysis?
Yes. The raw Gemini data is held in an MS Access 2000 database with an open defined format.

9) What other technologies does Gemini support e.g. 1327, GSM
Gemini has been developed specifically to meet TETRA market requirements however it is essentially technology independent therefore could be used for other technologies.

10) Is it possible to use vector mapping instead of bitmaps?
No. Gemini currently only supports bitmap maps.

11) Does Gemini log SMS or IP?
No. However the internal hooks for supporting these are in place and will be implemented in a future version.

12) How many radio terminals can Gemini connect to?
Gemini can support a maximum of 4 radio terminals simultaneously. They may be the same or different types, each separately configurable and will run independently of each other.

13) Can we network the Gemini PCs together to have a central database?
Yes. Gemini is scalable and the database structure easily accomodates a number of survey vehicles each collecting data and passing it back to a central main database for analysis.

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