Frequently Asked Questions
What is the accuracy of the GBSD Compass™ System?
The GBSD Compass™ System meets or exceeds FCC requirements.
What can be the maximum distance between cellular towers?
Recommended distance is six miles, but this can vary up or down depending on terrain, vegetation, and other obstacles.
Does the "String of Pearls" pose an issue to the Compass™ Location System?
This is irrelevant when considering our GSM Single-Site Location System. Depending on tower placement, an additional offset unit may be required for Analog and TDMA.
How do the antenna array components communicate with one another?
There are two methods of communication. The first, for antennas located on cell towers, is an IP address to each unit, creating the Compass network. For antennas located off of cell towers, we utilize a Maxstream wireless serial modem to establish connectivity between a central broadcast point and the unit.
Are the antenna array components part of the SS7 network?
The antenna arrays are not part of the SS7 network. They either belong to their own TCP/IP network or are controlled wirelessly.
Can the controller portion of the Compass™ Location System be purchased or may it be part of a hosted solution?
Yes, the controller may be purchased, and we offer licensing agreements for hosted solutions.
How fast can GBSD manufacture the antenna array components?
From date of order, there is a six to eight week window depending on the number of units ordered. Delivery is scheduled following this time period.
How is the Compass™ Location System calibrated?
The system is calibrated using the downlink of the neighboring cell site. Because of line-of-sight to the neighboring cell, the antenna array has a known accurate direction and is able to calibrate itself based on RF signals emitted from the site.
Must the antenna array component be located on top of the cellular tower?
No. Since the array is not part of the SS7 network, it has the flexibility to be located virtually anywhere (with power).
How is the antenna array component powered? Must coaxial cable be run up the tower?
The array is powered by a 120 VAC, with a 1U battery backup in the base station hut. We do not require any other lines to be run up the tower other than power.
What size unit is located in the base of the tower?
A 1U space is required for a battery backup.
Are the antenna array components LMUs, do they require LMUs to function, or is an LMU part of the design?
No.
What is the maximum distance between serial wireless modems?
Tested at 8 miles at 9600 baud successfully.
Do you require a TCP/IP address at each tower? Must the address be public or private?
Yes, as long as the array is located on one of your base stations. The address needs to be accessible via VPN.
Do you locate GSM phones using a Single Site Location (SSL) solution?
Yes, we support direction and distance from a single site, your base station, for GSM. To acquire distance, we use a demodulation schema to enhance the Timing Advance function received from the network.
What type of equipment does the SMLC / PDE controller require?
The controller uses an off-the-shelf data server with dual T1 cards and dual NICs, and the OS is centOS 4.1 (using the Linux 2.6 kernel).
If we use multiple switches, can your system handle them all? Must we purchase multiple controllers?
Yes, we handle multiple switches (up to 500,000 simultaneous connections). You do not need multiple controllers.
Do you offer Phase I?
Not at this time, but we do offer Phase I for testing only. This allows us to set up a testing environment away from a live PSAP.
Can you handle both 800 and 1900 TDMA/GSM?
Yes, with the same unit and components. The only components that change are the actual RF receiving components (filters, antennas, etc.), due to the different wavelengths involved.
Can the antenna array components be moved to another tower in the event a tower is sold to another company?
Yes. You own the array and it can be moved and recalibrated with minimal changes in the controller and the antenna array component.
What is the Lb interface and do you support it?
The Lb interface is the link between the SMLC and the base station controller. We support the U-TDOA, TA, and TOA messages.
What is the Ls interface and do you support it?
The Ls interface is the link between the MSC and the SMLC. We support PLR, PLResponse, MSPOSCOM, MSPOSResponse, and all COIN messages.
What interfaces have you tested?
E2, E3, E5, E5+, E11, E12, Lg, Ls, Lb
Does your equipment require three sites for triangulation and therefore location?
No. We require a minimum of two sites for Analog and TDMA, and one site for GSM.
