G2 Microsystems has developed the G2C501, a system-on-chip (SoC) that leverages the IEEE 802.11 (Wi-Fi) and the underlying Internet for both asset location and communication. The G2 Microsystems solution can be tailored to meet the demands of many applications because:
- Established Wi-Fi infrastructure for low total cost of ownership (TCO)
By leveraging existing 802.11 infrastructure for location calculations, G2’s technology eliminates the need for companies to build a proprietary network infrastructure to track assets. Eliminating the expense of readers/interrogators and their associated installation cost lowers the cost of an RTLS solution and allows a company to migrate from a small-scale solution to a company-wide implementation without high equipment costs. Back-office integration is also minimized with G2’s solution.
- Multiple location modes
G2 Microsystems integrates multiple location technologies that leverage existing 802.11, EPC, and ISO standards, enabling customers to use the one that best meets their needs in terms of location accuracy and cost. Our active RFID SoCs provide location based on Received Signal Strength Indicators (RSSI - values provided by 802.11 access points), Time Delay of Arrival (TDOA), and Location by Proximity methodologies.
- Ultra-low power management extending battery life
G2 Microsystems is the first company to develop an integrated circuit architecture that meets the demanding power requirements of active asset tracking tags. By doing so, we have lowered the power consumption of active asset tracking tags by an order of magnitude, significantly increasing the tag’s battery life. For example, a tag based on the G2C501 will last 1-5 years with two AA batteries. Current tags with the same configuration are only lasting a few months.
- Programmable sensor inputs allowing environmental awareness
In addition to location, G2-based tags can monitor and record environmental parameters such as temperature, pressure, shock, motion, and security. These parameters can be monitored continuously and stored on-chip until a WiFi connection is available.
- Always On Architecture
The G2C501 has an ultra low-power sleep mode where the sensor interface and real-time clock remain active. Both of these mechanisms can serve as wake-up events for the chip causing it to transition to its full active state.
LOCATION MODES
The G2C501 supports multiple location technologies, allowing G2-based tags to be located in a broad range of environments. To achieve the lowest total cost of ownership for an asset tracking system, G2-based tags can leverage existing 802.11 access points for location determination and communication. If greater accuracy or outdoor tracking is required, customers can utilize the IS0 24730-2 protocol that is also supported by the G2C501. G2-based tags also include an EPC interface that can be used to locate the tag as it moves through a normal supply chain.
802.11 MODE
The figure below shows the system configuration needed to locate, track and monitor assets using an 802.11 network.
System Operation using 802.11b Mode
The tag transmits ID and telemetry reports to 802.11 Wi-Fi access points. The access points measure the returned signal strength indication (RSSI) of the Wi-Fi signal and forward this data to a location engine which calculates the tag position. The position data as well as the status of the goods being tracked is then available to the tracking application.
In addition to determining the location of tagged assets, the tracking application can use the Wi-Fi network to send configuration data to the tag. This feature is useful both for doing the initial configuration of the tag as well as for updating tag parameters which control such things as the frequency and type of reports sent.
ISO 24730-2 MODE
The G2C501 has been designed to support the ISO 24730-2 (this standard is in the final process of being ratified). This standard is a superset of the ANSI 371.1 TOA protocol which was designed for asset tracking and has been shipping in products for a number of years. When using this protocol, the tag transmits 0dBm “blinks” with a 60MHz bandwidth using a DSSS modulated 2.4GHz ISM band carrier. Tags can be programmed using a magnetic data link, with a 2.4GHz OOK/FSK modulation scheme for command acknowledgement. The tag also sends specific DSSS-modulated signals when receiving signals from a magnetic choke-point transmitter.
System Operation in ISO 24730-2 Mode
EPC MODE
G2-based tags supports the full EPC Gen 1 Class 0 standard with extensions. The figure below shows the system configuration needed to read tag data and update tag contents using EPC technology. The EPC reader could be a hand-held device or a choke point.
System Operation using EPC Mode
SUPPORT FOR TELEMETRY
The G2C501 includes a general flexible interface, allowing G2-based tags to sense and monitor the environmental conditions surrounding a tagged item, ensuring it is properly handled. The sensor interface makes measurements of the tag environment according to the frequency specified by the tag program and can wake the tag when predetermined conditions are met.
These measurements can be reported directly back to the application as part of a report or they can be stored in either the on-chip non-volatile memory or in the external flash memory if an access point or reader is unavailable. The utilization of local storage allows the full history of the environmental conditions to be logged and communicated back to the application at a later time.
If goods are placed in an environment that will damage them, the tag could use the communication network to send an alarm. With the G2C501, environmental conditions can be reported back through the 802.11 access points, ISO 24730-2 readers, or EPC readers.
The G2C501 supports the following sensors:
MOTION
When programmed to detect motion, the G2-based tag will generate a wake up whenever the tag is moved. In addition to monitoring the movement of an asset, motion detection can be used to save on power consumption by powering down the chip during periods of inactivity. This function is able to distinguish between vibration and movement. A tag performing this function requires a ball-in-tube motion sensor or a MEMS accelerometer.
TEMPERATURE
The ability to sense the temperature of tagged assets is critical for some applications like cold storage, allowing action to be taken when the temperature goes out of range, before spoilage occurs. The sensor interface, when used with an external sensor, can measure the ambient temperature surrounding the tag to an accuracy of 1°C over the range -40°C to +55°C, or to a 0.1C accuracy over the range 0°C to +30°C. Depending on the tag application, the G2C501 could generate a visible alarm or send a message over WiFi when the temperature goes out of range.
SECURITY
Ensuring the security of assets has become a more prominent user requirement, both for purposes of homeland security and as a means of reducing counterfeiting. The G2C501 monitors a closed loop to detect whenever a security seal state changes. Whenever this condition is detected, the G2C501 can be programmed to trigger an alarm, log the occurrence, or send a message.
SHOCK
Detection of shock is useful in such applications as shipping, where a time stamp could be recorded when a tagged asset is dropped and possibly damaged.The G2 chip, when combined with a suitable accelerometer can digitize the tag’s acceleration whenever it exceeds a preset threshold, allowing the impact and orientation of the event to be assessed at a later time.
HUMIDITY
Monitoring humidity is a key requirement for proper food storage. Different foods require different conditions. A G2-based tag can record the humidity of its environment and store this data for later retrieval. It can also generate and alarm or send a message when preset limits are exceeded.
PRESSURE
Monitoring pressure is valuable for process monitoring, and is appealing in applications such as tire sensing. Automatic tire sensing improves safety and enables preventative maintenance; it is likely to become a mandated requirement as part of the TPMS regulation proposals.
RADIATION
Radiation monitoring is getting increased interest due to homeland security concerns. Like the other sensed parameters, the G2-based tag can send an alarm when an external radiation sensor measures a value exceeding a preset threshold.
DESIGNED FOR ULTRA LOW BATTERY CONSUMPTION
There are several systems on the market today that use 802.11b networks for tracking people and assets. These systems have a low total-cost of ownership, are simple to install, flexible and have many applications. However, many of these systems suffer from a short battery life.
The G2C501 has been designed from inception to maximize battery life and achieves ultra low-power consumption with a combination of proprietary technologies. The power conservation architecture operates in two modes: an active mode and a sleep mode. In active mode, the G2C501 manages all functions of the tag so that power is supplied to a particular function only for the time needed. This is particularly important as the frequency of reporting increases. In sleep mode, a large portion of the chip is powered down however the tag continues to monitor outside conditions. Depending on the battery selected for the tag, the reporting frequency, and the application requirements, battery life can be as high as seven years.
Below is a graph showing the battery life requirements and reporting frequency for a number of applications. Although 802.11-based asset tracking solutions have been well received, the battery life of the active tags has been a limiting factor. With G2-based tags, the battery life will be extended significantly, making it an attractive solution across a number of new markets.
LOW TOTAL COST OF OWNERSHIP (TCO)
The total cost of ownership (TCO) of wireless 802.11-based systems is lower than solutions based on proprietary technology because the 802.11-based system leverages existing infrastructure and fixed maintenance costs. Today, a number of real-time location solutions are based on proprietary protocols running at various frequencies (most are operating at either 433 MHz or 915 MHz). The tags are built with off-the-shelf components and require a proprietary reader or interrogator to communicate with the tag.
ALWAYS ON ARCHITECTURE
The G2C501 has an ultra low-power sleep mode where the sensor interface and real-time clock remain active. Both of these mechanisms can serve as wake-up events for the chip causing it to transition to its full active state.
