I need an embedded software engineer

Electro-Technik (Systems) Ltd. are looking at the possibility of subcontracting the design and writing of embedded software to up-grade an existing project based on an Atmel AT-Mega2560 microcontroller. The unit to be programmed is an aircraft activity logger. The AT-Mega2560 based hardware already exists and approximately one hundred units are in operation. On board peripherals include GPS /GNSS / GLONASS receiver (u-blox) Cellular 2G and LTE modem (u-blox) Sound level monitoring Altitude (atmospheric pressure) monitoring Vibration monitoring (3 axis accelerometers) PSU with Li-Po battery charging Non volatile memory (1Mb) and RTC The function of the module is to record the time at which aircraft events occur and at the end of the flight to send a record of these times via the cellular phone network using the MQTT protocol. Recordable aircraft events include switch on, start of taxying, take off (or hovering), landing, end of taxying and shutdown. In addition, aircraft location latitude, longitude and altitude may also need to be recorded and reported. The existing hardware is based on the Atmel AT-Mega 2560, but future versions may utilise the STM32 microcontroller. The existing C code would be made available, and it would be preferred if the new code were also written in C or C++. The project is based in Teesside in the North East of England, and it would be essential for the developer to be based relatively locally. Please provide details of experience, hourly rates and fixed contract price